Effect of Temperature and Initial Moisture Content on the Heat of Wetting of Wood

Nature ◽  
1955 ◽  
Vol 176 (4471) ◽  
pp. 83-84 ◽  
Author(s):  
KATHLEEN E. KELSEY ◽  
L. N. CLARKE
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Effect Of Temperature ◽  
Heat Of Wetting

THE EFFECT OF TEMPERATURE DIFFERENTIAL ON THE MOISTURE CONTENT OF STORED WHEAT

1943 ◽  
Vol 21c (10) ◽  
pp. 297-306 ◽  
Author(s):  
J. Ansel Anderson ◽  
J. D. Babbitt ◽  
W. O. S. Meredith
Keyword(s):  
Moisture Content ◽  
Laboratory Experiment ◽  
Water Vapour ◽  
Initial Moisture Content ◽  
Effect Of Temperature ◽  
Western Canada ◽  
Temperature Differential ◽  
Slow Process ◽  
Equilibrium Conditions ◽  
Convective Movement

Local increases in the moisture content of dry wheat stored in country elevator annexes have occasionally been observed in Western Canada. A laboratory experiment suggests that the chief cause is a temperature differential established during the winter. The air in the warmer parts of the grain contains a greater quantity of water vapour than that in the colder, and moisture is transferred either by diffusion or by the convective movement of the air as a whole. A temperature difference of 35 °C, across 6 ft. of grain having an initial moisture content of 14.6%, caused the moisture content at the cold end (0 °C.) to rise to over 20% in 316 days. The experiment indicates that this movement of moisture is a slow process and that equilibrium conditions are never established for any practical length of time or mass of wheat.

scholarly journals Experimental Study of Drying Parameters of Ginger at Different Temperature and Moisture Content

2018 ◽  
Vol 3 (9) ◽  
pp. 34
Author(s):  
Olusegun Solomon Olaoye ◽  
A. J. Ogunleye
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Thermal Diffusivity ◽  
Moisture Content ◽  
Specific Heat ◽  
Initial Moisture Content ◽  
Moisture Diffusion ◽  
Effect Of Temperature ◽  
Clean Water ◽  
Heat Treated

Drying provides extended shelf life to agricultural crops in general and thus proper design of dryer will assist in drying them to acceptable level and quality. To design adequate dryer, necessary drying parameters of drying materials is necessary. This work involves experimental determination of effective drying parameters such as moisture content, moisture diffusion coefficient, density (true and bulk), specific heat, thermal conductivity and thermal diffusivity of ginger and to analyze these parameters in relation to each other. Fresh ginger rhizomes were washed to remove soil from the field, peeled and washed again in clean water and sliced into thin pieces. The sliced ginger was heat-treated by adding 200ml of clean water and steaming for 5–8 minutes in an aluminum pot, to a temperature of 85–90 oC, and a light brown colour. Microwave oven, calorimeter, desiccators, thermometers, triple beams balance, micrometer screw gauge were used to determine the drying parameters of ginger. Effect of temperature and moisture content on some thermal properties was determined. The results of the experiments shows that average initial moisture content for the ginger samples was 72.31%, the true and bulk densities of the sample increased linearly from 0.5809 to 0.6338g/cm3 and 0.7405 to 0.7972 g/cm3 respectively between the temperatures of 45 – 75 °C. The specific heat capacity of ginger varied from a minimum of 1.568kJkg-1K-1 to a maximum of 2.026kJ kg-1K-1, with temperature in the range of 45oC to 75oC and moisture content in the range of 24.43 to 46.19 % (d.b). The thermal conductivity of ginger samples varied from 0.316×10-3 to 9.763×10-4 Jm-1S-1 oC; as the moisture content and temperature increased. Thermal diffusivity of the ginger increased linearly from 3.149×10-8 to 4.438×10-8 m2s-1 for ginger with increase in moisture content and temperature. Conclusively, the experimental study analysis show that specific heat of ginger varies with temperature. Also, there is variation in length, breath and thickness of ginger when subjected to temperature. Therefore, it can be said that ginger do shrinks when it is subjected to heat.

Infiltration and structural changes as influenced by initial moisture content

Soil Research ◽  
1971 ◽  
Vol 9 (2) ◽  
pp. 107 ◽  
Author(s):  
N Collis-George ◽  
R Lal
Keyword(s):  
Moisture Content ◽  
Structural Changes ◽  
Initial Moisture Content ◽  
Infiltration Rate ◽  
Surface Layers ◽  
Infiltration Process ◽  
Moisture Condition ◽  
Heat Of Wetting ◽  
Cumulative Infiltration ◽  
Entrapped Air

The variation of infiltration behaviour, in columns of aggregates of a structurally stable and an unstable soil, caused by pre-equilibrating the aggregates with a range of relative humidities from 0 to 98%, was measured in terms of advance of the front, cumulative infiltration, slaking, and swelling. In this range, the effect of initial moisture condition on the stable soil (krasnozem) was slight compared with that on the unstable soil (black earth); the wetter the soil initially, the greater was the infiltration rate, and the smaller the slaking and swelling. The change in the behaviour of infiltration into systems of stable aggregates is reflected as (1) an increase in the importance of the sorptivity, and (2) a reduction in the importance of the hydraulic conductivity contribution to the steady-state infiltration process. (The aggregates of 1/2-1 mm are of such a size that the sorptivity contribution should not normally be detectable in stable soils.) It is suggested that in the unstable soil, the heat of wetting is associated with aggregate collapse. The degraded structure of the surface layers prevents fast entry of water into the lower layers. The collapse of structure dominates the infiltration process so that the analysis in terms of sorptivity carried out for stable aggregates cannot be made. The effect of entrapped air on slaking of aggregates of these soils is shown to be negligible compared with the effect of initial moisture content. The application of the results to flood irrigation of unstable soils under field conditions is briefly considered.

Examination of Tobacco Hygroscopicity / Über die Hygroskopizität des Tabaks

1965 ◽  
Vol 3 (1) ◽  
Author(s):  
L. Hübschen
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Initial Moisture Content

AbstractThe present paper shows the detectable factors on which a sorption isotherm depends. Even if it is well-known that a sorption isotherm is most essentially conditioned by influences of the respective tobacco variety, other factors, such as temperature, initial moisture content, or fibre dimension, play a part as well. In general, a sorption isotherm constitutes a ''summation'' of such factors and, in the end, a combination of desorption and adsorption if the tobacco is dried or moistened from the average commercial moisture content. The tobacco hysteresis is experimentally investigated and discussed

Pengeringan Biji Kakao dengan Pengering Surya Tipe Terowong Berpenggerak Sel Fotovoltaik di Manokwari

Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Wilson Palelingan Aman
Keyword(s):  
Moisture Content ◽  
Performance Test ◽  
Initial Moisture Content ◽  
Maximum Temperature ◽  
Photovoltaic Module ◽  
Cocoa Beans ◽  
Drying Time ◽  
Tunnel Dryer ◽  
Heat Collector ◽  
New Construction

<em>A research about cocoa beans drying used solar tunnel dryer with photovoltaic module driven have conducted in Manokwari. Solar tunnel dryer used in this research adapted from type Hohenheim with photovoltaic module and integrated air heat collector has been installed at the Department of Agricultural Technology, Papua State University Manokwari to dried cocoa beans. The objectives of this research were to design solar tunnel dryer and evaluate it�s performance in dryed cocoa beans. The result obtained was a new construction of solar tunnel dryer for cocoa beans with dimensions 6 m of length and 0,9 m of wide. The dryer completed with photovoltaic module to drive the blowers of hot drying air. �Performance test of the dryer showed that drying of 10 kg of cocoa beans with initial moisture content about 70% wet basis needed 13 hours of drying time to achieved final moisture content about 7,17% wet basis. The drying time achieved was faster compared than traditional solar drying that needed 20 hours of drying time. The maximum temperature achieved in drying chamber was 60 <sup>o</sup>C.</em>

scholarly journals Wood Chip Drying through the Using of a Mobile Rotary Dryer

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1590 ◽  
Author(s):  
Angelo Del Giudice ◽  
Andrea Acampora ◽  
Enrico Santangelo ◽  
Luigi Pari ◽  
Simone Bergonzoli ◽  
...  
Keyword(s):  
Moisture Content ◽  
Power Plants ◽  
Black Locust ◽  
Thermal Power ◽  
Initial Moisture Content ◽  
Wood Chip ◽  
Wood Chips ◽  
Cocurrent Flow ◽  
Drying Process ◽  
Rotary Dryer

Drying is a critical point for the exploitation of biomass for energy production. High moisture content negatively affects the efficiency of power generation in combustion and gasification systems. Different types of dryers are available however; it is known that rotary dryers have low cost of maintenance and consume 15% and 30% less in terms of specific energy. The study analyzed the drying process of woody residues using a new prototype of mobile rotary dryer cocurrent flow. Woodchip of poplar (Populus spp.), black locust (Robinia pseudoacacia L.), and grapevine (Vitis vinifera L.) pruning were dried in a rotary drier. The drying cycle lasted 8 h for poplar, 6 h for black locust, and 6 h for pruning of grapevine. The initial biomass had a moisture content of around 50% for the poplar and around 30% for grapevine and black locust. The study showed that some characteristics of the biomass (e.g., initial moisture content, particle size distribution, bulk density) influence the technical parameters (i.e., airflow temperature, rate, and speed) of the drying process and, hence, the energy demand. At the end of the drying process, 17% of water was removed for poplar wood chips and 31% for grapevine and black locust wood chips. To achieve this, result the three-biomass required 1.61 (poplar), 0.86 (grapevine), and 1.12 MJ kgdry solids−1 (black locust), with an efficiency of thermal drying (η) respectively of 37%, 12%, and 27%. In the future, the results obtained suggest an increase in the efficiency of the thermal insulation of the mobile dryer, and the application of the mobile dryer in a small farm, for the recovery of exhaust gases from thermal power plants.

scholarly journals Effects of microwave irradiation on the moisture content of various wood chip fractions obtained from different tree species

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Monika Aniszewska ◽  
Krzysztof Słowiński ◽  
Ewa Tulska ◽  
Witold Zychowicz
Keyword(s):  
Moisture Content ◽  
Microwave Irradiation ◽  
Microwave Power ◽  
Irradiation Time ◽  
Initial Moisture Content ◽  
Radiant Energy ◽  
Wood Chip ◽  
Wood Chips ◽  
Chip Size ◽  
Drying Rates

AbstractThe paper proposes the use of microwave irradiation to lower the initial moisture content of wood chips. The study involved willow and fir chips fractionated by means of a sieve separator and unfractionated ash chips. The wood chips were exposed to a constant microwave power of 800 W for 30 s, 60 s, 120 s and 180 s. The chips were weighed before and after irradiation to measure loss of moisture. It was found that the decline in moisture content increased with wood chip size for a given irradiation time and microwave power. The initial moisture content of wood chips was not found to significantly affect loss of moisture as the drying rates of wood chips with higher and lower moisture content exposed to microwaves were not statistically different. The results showed that irradiation intensity increased with the time of exposure to microwaves and unit radiant energy per unit of evaporated moisture decreased with increasing wood chip size in the 3.15–31.50 mm range.

scholarly journals Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Oven Drying ◽  
Sun Drying ◽  
Different Temperatures ◽  
Final Water Content ◽  
Drying Curves ◽  
Drying Conditions

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.

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