Relative humidity, temperature, and the equilibrium moisture content of conidia of Beauveria bassiana (Balsamo) Vuillemin: a quantitative approach

2002 ◽  
Vol 38 (1) ◽  
pp. 33-41 ◽  
Author(s):  
T.D. Hong ◽  
R.H. Ellis ◽  
J. Gunn ◽  
D. Moore
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Beauveria Bassiana ◽  
Quantitative Approach

Comparative Analysis of Sorption Isotherms for Wood Pellets and Solid Wood

2019 ◽  
Vol 35 (4) ◽  
pp. 475-479 ◽  
Author(s):  
Jun Sian Lee ◽  
Shahab Sokhansanj ◽  
C. Jim Lim ◽  
Anthony Lau ◽  
Tony Bi
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Solid Wood ◽  
Wood Chips ◽  
Published Data ◽  
Wood Pellets ◽  
Wood Pellet ◽  
Equilibrium Relative Humidity

Abstract.The published data on equilibrium moisture content vs. equilibrium relative humidity (EMC-ERH) for wood pellet do not cover the range of temperature and relative humidity to which a pellet is exposed to during its storage and handling. A few published EMC-ERH relations covering a wider range of temperatures and relative humidity are available for solid wood (lumber) and wood chips. The question is whether the data for solid wood is applicable to wood pellets. For this research, we examined the sorption isotherms of wood pellets and solid wood. The analysis shows that EMC for solid wood is higher than the EMC for wood pellet for a relative humidity larger than 30%. The slope of EMC-ERH isotherm for solid wood in the range of 30%-70% is slightly steeper than the slope of isotherm for wood pellet, indicating the pellet’s EMC is less sensitive to ERH when compared to EMC-ERH for solid wood. Keywords: EMC, ERH, Densified biomass, Equilibrium moisture content, Equilibrium relative humidity, Solid wood, Wood pellets.

Sorption Isotherms and Isosteric Heat of Peanut Pods, Kernels and Hulls

2007 ◽  
Vol 13 (3) ◽  
pp. 231-238 ◽  
Author(s):  
P.C. Corrêa ◽  
A.L.D. Goneli ◽  
C. Jaren ◽  
D.M. Ribeiro ◽  
O. Resende
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Moisture Content ◽  
Mathematical Models ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Statistical Parameters ◽  
Peanut Hulls ◽  
Pass Through

This study was carried out to evaluate the sorption isotherms of peanut pods, kernels and hulls for several temperature and humidity conditions and to fit different mathematical models to the experimental data, selecting the one best fitting the phenomenon. The dynamic method was applied to obtain the hygroscopic equilibrium moisture content. The environmental conditions were provided by means of an atmospheric conditioning unit, in which removable perforated trays were placed to allow air to pass through peanut mass, each one containing 50 g of the product. The mathematical models frequently used for the representation of hygroscopicity of agricultural products were fit to the experimental data. Based on those results, it was concluded that peanut pods, kernels and hulls presented differentiated hygroscopicity. The equilibrium moisture content for peanut pods, kernels and hulls increased with an increase in the relative humidity at any particular temperature and decreased with increase in temperature at constant relative humidity. At a constant water activity, peanut hulls samples had higher equilibrium moisture content than the pods and kernels samples. Based on statistical parameters, the modified Henderson and Chung-Pfost models were found to adequately describe the sorption characteristics of peanut pods, kernels and hulls. Isosteric heat of desorption were evaluated by applying the Clausius—Clapeyron equation to experimental isotherms and decreased with increasing moisture content. The peanut hulls had higher isosteric heat of sorption than that peanut pods and kernels.

scholarly journals Moisture content changes of beech and ash elements during two years in room conditions

2021 ◽  
pp. 97-110
Author(s):  
Goran Milic
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Air Conditioning ◽  
Cold Winter ◽  
The Past ◽  
Average Relative Humidity ◽  
The Subject ◽  
Sawn Timber

The subject of this paper is the analysis of moisture content (MC) changes of beech and ash wood during two years in room conditions (heating during winter; no air conditioning during summer). The registered MC changes are primarily the result of changes in relative humidity of the air (measured by capacitive probes). The average relative humidity of the air in the interior is lower today than in the past, as also shown in this experiment (the average relative humidity of air during two years was 44%). The lowest wood MC was reached on very cold winter days when the heating was on even during the night - between 5% and 6%, and the highest one at the beginning of June: 10.4-10.9%. As expected, the wood did not reach equilibrium moisture content - during winter, MC is by about 1% higher, and in summer it is lower by up to 2.5% than the equilibrium. The recommendation that the sawn timber from which the interior products will be made should be dried at 7-8% MC was confirmed.

The Horizontal Flame-Propagation Rate of Undyed Cotton Fabrics

1976 ◽  
Vol 46 (4) ◽  
pp. 238-246 ◽  
Author(s):  
Leon Segal ◽  
G. L. Drake
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Flame Propagation ◽  
Propagation Rate ◽  
Cotton Fabrics ◽  
Horizontal Position ◽  
Test Procedures ◽  
Oven Drying ◽  
Usual Test

Differentiation of the flammabilities of nonflame-retardant, all-cotton fabrics cannot be accomplished by the usual test procedures, as these merely provide the means for determining when a fabric exceeds a certain set standard. The desired differentiation, however, can be obtained by measurement of the flame-propagation rate using the Ahiba Flammability Tester with the sample in the horizontal position. Eight nonflame-retardant, undyed cotton fabrics of different constructions were studied. The weights of the fabrics fell into four groups: 3.1, 3.6–3.8, 4.1–4.4, and 7.5 oz/yd2. Specimens were cut from the warp and filling directions of the fabrics; one set of specimens was oven-dried prior to testing, while another set was conditioned to equilibrium moisture content at 65% relative humidity and 70°F. Burning was different in the warp and filling directions. Differences in flame-propagation rates were found that were not weight dependent. In general, flame-propagation rate was not constant over the length of the specimen; in the warp direction the rates increased with distance from point of ignition, while in the filling direction constant and decreasing rates were also found. Flame-propagation rate was not effected to the extent expected by changing from oven drying to conditioning to equilibrium moisture content; only four of the eight fabrics showed significant changes. Burning in the filling directions of two fabrics was markedly changed; smaller differences were found in the warp direction only of a third fabric and in both the warp and filling directions of a fourth fabric.

Effects of Post-Harvest Conditions on Sorption Isotherms of Soybeans

2021 ◽  
Vol 64 (3) ◽  
pp. 1027-1037
Author(s):  
Lina M Diaz-Contreras ◽  
Rani Puthukulangara Ramachandran ◽  
Stefan Cenkowski ◽  
Jitendra Paliwal
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Freezing And Thawing ◽  
Post Harvest ◽  
Drying And Wetting Cycles ◽  
Equilibrium Relative Humidity ◽  
Freezing And Thawing Cycles ◽  
Storage Temperatures

Abstract. This study focuses on the modeling of sorption characteristics of three varieties of soybeans (Akras R2, Lono R2, and Podaga R2). Three pretreatments related to post-harvest conditions were tested on the soybean varieties: (1) freshly harvested soybeans, (2) soybeans subjected to three drying and wetting cycles, and (3) soybeans subjected to three freezing and thawing cycles. The adsorption and desorption experiments were conducted at 5°C, 10°C, 15°C, 20°C, 25°C, and 30°C using a dynamic equilibrium relative humidity (ERH) apparatus. Equilibrium moisture content (EMC) and the corresponding ERH were measured. The parameters calculated for the modified Halsey equation are applicable for storage temperatures above 10°C in the relative humidity (RH) ranges of 10% to 80% for desorption and 30% to 80% for adsorption. No significant differences were found in sorption isotherms among the soybean varieties. However, the soybean varieties responded differently to the different pretreatments (i.e., drying/wetting and freezing/thawing cycles). The adsorption isotherms of Akras and Lono soybeans showed significant differences at 10°C to 30°C when subjected to drying and wetting cycles, while Akras and Podaga soybeans showed significant differences in the same temperature range when subjected to freezing and thawing cycles. The effect of drying and wetting cycles on the desorption isotherms was found only for Akras soybeans at 10°C and 15°C below 63% and 71% RH, respectively, and for Lono soybeans at 25°C and 30°C above 69% RH for both temperatures. In general, the effect of both pretreatments on the sorption isotherms of soybeans was a reduction in EMC of up to 20%, when compared to fresh samples at selected storage temperatures. The findings of this study serve as a primary tool for developing a lookup table for safe storage guidelines for soybeans. Keywords: Equilibrium moisture content, Equilibrium relative humidity, Halsey equation, Oswin equation, Soybeans.

scholarly journals EFEITO DA VAPORIZAÇÃO NA UMIDADE DE EQUILÍBRIO E SUA IMPLICAÇÃO NAS PROPRIEDADES MECÂNICAS DA MADEIRA DE Eucalyptus dunnii MAID

FLORESTA ◽  
2001 ◽  
Vol 31 (12) ◽  
Author(s):  
Elias Taylor Durgante Severo ◽  
Ivan Tomaselli ◽  
Ghislaine Miranda Bondueli ◽  
Marcos Antônio De Rezende
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Eucalyptus Dunnii ◽  
Remarkable Reduction ◽  
Different Levels ◽  
Do So

O objetivo deste estudo foi avaliar o efeito da vaporização sobre a umidade de equilíbrio e sua implicação nas propriedades mecânicas da madeira de Eucalyptus dunnii. Para isso de um lote de toras desta espécie separou-se cerca de 1/3 para controle, enquanto o restante foi submetido à vaporização nas condições de temperatura e umidade relativa de 100ºC e 100%, respectivamente. Após retirar-se uma prancha central destas toras, as mesmas foram transformadas em vigotas de 8 cm x 8 cm. Entre as vigotas provenientes das toras vaporizadas cerca da metade foi novamente vaporizada nas mesmas condições previamente descritas por um período de 3 horas após uma hora de aquecimento inicial. Desta forma obteve-se três níveis de comparação (controle, vaporizado em toras e madeira pré-vaporizada). Posteriormente estas vigotas foram transformadas em corpos-de-prova segundo a norma COPANT e condicionados em câmara climatizada a 21ºC e 65% de temperatura e umidade relativa, respectivamente. Os resultados mostraram uma redução significativa no teor de umidade de equilíbrio entre os níveis de vaporização empregados e madeira controle, evidenciando a necessidade da correção das propriedades mecânicas da madeira desta espécie para um mesmo teor de umidade antes de sua utilização. Vaporization effect on the equilibrium moisture content and its implication on the mechanical properties in Eucalyptus dunnii wood Abstract The aim of this study was to evaluate the vaporization effects on the equilibrium moisture content and its implication on the mechanical properties of Eucalyptus dunnii. To do so, about two thirds of the logs were vaporized at 100oC and 100% (temperature and relative humidity respectively) for 20 hours, while the remaining logs were kept as control. From each log, a central plank with 8 cm of thickness is taken, from which small beams of 8 cm x 8 cm was taken. Half of the small beams from the vaporized logs were once again submitted to vaporization under the same previously described conditions for a period of 3 hours, thus obtaining three different levels of comparison (control, vaporized on logs and presteaming wood). Subsequently the beams were transformed in samples by the COPANT norm and conditioned in climatized kiln (21ºC/65% relative humidity) until the higorscopic equilibrium. The results showed a remarkable reduction on the equilibrium moisture content with the vaporization conditions used, showing the necessity of the mechanical properties correction to the same moisture content.

scholarly journals Physicochemical Properties of Briquettes from Different Feed Stock

2015 ◽  
Vol 10 (1) ◽  
pp. 263-269 ◽  
Author(s):  
D Vyas ◽  
F Sayyad ◽  
M Khardiwar ◽  
Shailendra Kumar
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Chemical Properties ◽  
High Humidity ◽  
Feed Stock ◽  
Physico Chemical ◽  
Combustion Properties ◽  
Different Types ◽  
The Difference

This study was undertaken to evaluate the Physico-chemical properties of eight different types of biomass feed stock and their briquettes were studied among that some properties which are influence their storage and combustion properties like Equilibrium moisture content (EMC %) and Relative humidity (%). Equilibrium moisture content are found out by static equilibrium technique using aqueous glycerol solutions of different concentrations in the relative humidity (RH) range of 40 to 90 % and at ambient temperature between 25 to 37 ºC. The Equilibrium moisture content of briquettes was lower than their feedstock by about 1 – 2.5 % in all the cases ranges from 40 to 70 % RH. At higher RH above 70%, the difference was between 2 - 4%. There was no change in the shape of the briquettes at all levels of RH. This was due to higher density of briquettes. This study showed during period of high humidity, the storage of briquettes will not create any problem and will be safer as compared to their feedstock.

Modeling of the Equilibrium Moisture Content (EMC) of Tarragon (Artemisia Dracunculus L.)

2005 ◽  
Vol 1 (5) ◽  
Author(s):  
Akbar Arabhosseini ◽  
Willem Huisman ◽  
Anton van Boxtel ◽  
Joachim Müller
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Relative Deviation ◽  
Artemisia Dracunculus ◽  
Significant Difference ◽  
Moisture Sorption Isotherms ◽  
The Relationship

The equilibrium moisture content of tarragon, Artemisia dracunculus L. (stem and leaf separately) was determined by using the saturated salt solutions method at three temperatures (25, 50 and 70°C) within a range of 5 to 90% relative humidity. Both adsorption and desorption methods were used for stem and leaf of two varieties: Russian and French tarragon. Experimental curves of moisture sorption isotherms were fitted by modified Henderson, modified Halsey, modified Oswin, modified Chung-Pfost and GAB equations and evaluated by residual sum squares, standard error of estimate and mean relative deviation. The modified Halsey and GAB equations were found to be the most suitable for describing the relationship among equilibrium moisture content, relative humidity and temperature. There was no significant difference between the equilibrium moisture content of the Russian and French tarragon.

The storage of artificially dried grass

1941 ◽  
Vol 31 (2) ◽  
pp. 194-211 ◽  
Author(s):  
Norman C. Wright
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Low Power ◽  
Equilibrium Moisture Content ◽  
Early Stage ◽  
Smooth Curve ◽  
Storage Conditions ◽  
Mould Growth ◽  
Safe Storage ◽  
Winter Conditions

1. Experiments have been carried out to determine the relation between the moisture content of artificially dried grass and the relative humidity of the surrounding atmosphere. This relation is given by a smooth curve. At relative humidities which are typical of outdoor winter conditions in the British Isles (80–90%) the equilibrium moisture content lies between 18 and 30%.2. The rate of moulding is directly related to the relative humidity and therefore to the moisture content of the dried grass. For reasonably safe storage a relative humidity of 67 % should not be exceeded. This corresponds to a moisture content of roughly 13 %. Even this low value does not confer absolute immunity from mould growth.3. The importance of extending storage trials over long periods is stressed. In one instance storage for 300 days was required before mould growth occurred. Neglect of this fact may account for the widely held view that a relative humidity of 70–75 % provides safe storage conditions.4. Attempts to detect mould growth at an early stage by plating methods proved unsuccessful. It is shown that the two earliest and most reliable indications of mould growth are (i) the appearance of visible mycelium when the product is examined under a low-power objective, and (ii) the detection of a musty smell.

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