Effects of Controlled Relative Humidity Storage on Moisture Sorption and Amylopectin Retrogradation in Gelatinized Starch Lyophiles

2019 ◽  
Vol 84 (3) ◽  
pp. 507-523 ◽  
Author(s):  
Kathryn A. Johnson ◽  
Lisa J. Mauer
Keyword(s):  
Relative Humidity ◽  
Moisture Sorption ◽  
Amylopectin Retrogradation ◽  
Gelatinized Starch

Dynamic moisture sorption and dimensional stability of furfurylated wood with low lignin content

Holzforschung ◽  
2019 ◽  
Vol 74 (1) ◽  
pp. 68-76
Author(s):  
Tiantian Yang ◽  
Erni Ma ◽  
Jinzhen Cao
Keyword(s):  
Relative Humidity ◽  
Dimensional Stability ◽  
Furfuryl Alcohol ◽  
Lignin Content ◽  
Moisture Sorption ◽  
Dimensional Change ◽  
Poplar Wood ◽  
Sorption Coefficient ◽  
Dimensional Changes ◽  
Sinusoidal Shape

AbstractDegradation of lignin occurs naturally in wood due to the influence of microorganisms or photic radiation. To improve the properties of wood with low lignin content, furfuryl alcohol (FA) at the concentration of 25% was used to modify poplar wood (Populus euramericana Cv.) after partial delignification. Moisture sorption and dimensional stability of the samples were investigated under dynamic conditions where the relative humidity (RH) was changed sinusoidally between 45% and 75% at 25°C. Both the moisture content (MC) and the tangential dimensional change varied with a sinusoidal shape similar to the RH. Hygroscopicity and hygroexpansion increased after delignification, while furfurylation led to an inverse impact by reducing MC, dimensional changes, amplitudes of MC and dimensional changes, moisture sorption coefficient (MSC), and humidity expansion coefficient (HEC). After delignification and further furfurylation, the MC and the dimensional changes were reduced by about 20%, and the maximum drop in amplitudes of MC and dimensional changes was about 30%, while the MSC and the HEC decreased by over 15%. In addition, the furfurylated wood with low lignin content exhibited lower sorption hysteresis and swelling hysteresis.

scholarly journals Modeling Indoor Relative Humidity and Wood Moisture Content as a Proxy for Wooden Home Fire Risk

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5050 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Moisture Sorption ◽  
Fire Risk ◽  
Cold Weather ◽  
Indoor Climate ◽  
Ambient Conditions ◽  
Wood Panel ◽  
Fire Disaster ◽  
Strong Winds

Severe wooden home conflagrations have previously been linked to the combination of very dry indoor climate in inhabited buildings during winter time, resulting in rapid fire development and strong winds spreading the fire to neighboring structures. Knowledge about how ambient conditions increase the fire risk associated with dry indoor conditions is, however, lacking. In the present work, the moisture content of indoor wooden home wall panels was modeled based on ambient temperature and relative humidity recorded at meteorological stations as the climatic boundary conditions. The model comprises an air change rate based on ambient and indoor (22 °C) temperatures, indoor moisture sources and wood panel moisture sorption processes; it was tested on four selected homes in Norway during the winter of 2015/2016. The results were compared to values recorded by indoor relative humidity sensors in the homes, which ranged from naturally ventilated early 1900s homes to a modern home with balanced ventilation. The modeled indoor relative humidity levels during cold weather agreed well with recorded values to within 3% relative humidity (RH) root mean square deviation, and thus provided reliable information about expected wood panel moisture content. This information was used to assess historic single home fire risk represented by an estimated time to flashover during the studied period. Based on the modelling, it can be concluded that three days in Haugesund, Norway, in January 2016 were associated with very high conflagration risk due to dry indoor wooden materials and strong winds. In the future, the presented methodology may possibly be based on weather forecasts to predict increased conflagration risk a few days ahead. This could then enable proactive emergency responses for improved fire disaster risk management.

scholarly journals Drying and rehydration of oyster mushroom

2010 ◽  
Vol 53 (4) ◽  
pp. 945-952 ◽  
Author(s):  
Giannini Pasiznick Apati ◽  
Sandra Aparecida Furlan ◽  
João Borges Laurindo
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Pleurotus Ostreatus ◽  
Water Sorption ◽  
Room Temperature ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Fruiting Bodies ◽  
Different Temperatures ◽  
Water Sorption Isotherms

Dehydration and rehydration processes of Pleurotus ostreatus fruiting bodies were investigated in this work. Mushroom samples were dehydrated at 40, 50 and 60 ºC, using drying air with relative humidity of 75 %. The rehydration was investigated at different temperatures of immersion water (25, 55 and 85 ºC) and different immersion times (30, 75 and 120 minutes). The best rehydration occurred for the samples dried at 40 ºC. The rehydration could be done in water at room temperature, during 30 minutes. Water sorption isotherms of samples were determined at 30, 40 and 50 ºC. Both GAB and BET models satisfactorily represented the experimental data of moisture sorption of dried mushrooms.

scholarly journals Characterization of the Hygrothermal Properties of Wood Fibre Insulaton Board

2021 ◽  
Author(s):  
Kelly Leanne Fordice
Keyword(s):  
Relative Humidity ◽  
Moisture Sorption ◽  
Wood Fibre ◽  
Variable Nature ◽  
Manufactured Products ◽  
High Thermal Resistance ◽  
Moisture Storage ◽  
Increasing Temperature

High thermal resistance building envelopes comprising wood fibre insulation board (WFIB) contribute to a reduction in building energy consumption associated with unwanted heat losses and gains. The longterm performance and durability of the WFIB material may perform differently than expected due to the temperature and moisture dependent material characteristics, including moisture sorption, vapour permeance, and thermal conductivity. This research investigated the characterization of hygrothermal properties of WFIB at temperatures and relative humidities expected for a Canadian climate. The hygrothermal characteristics of WFIB were determined to have a range of values as a result of the variable nature of wood fibre materials with temperature and moisture, and the variability of WFIB materials amongst manufactured products. The variabilities of these hygrothermal properties are expected to impact the materials overall moisture storage at various in-situ temperature and relative humidity conditions, and the materials ability to transport moisture at various in-situ temperature and relative humidity conditions. Additionally, the thermal performance of WFIB is expected to vary with in-situ temperature and relative humidity conditions, with increased thermal losses/gains with increasing temperature and increasing relative humidities.

Moisture Sorption Isotherms of Lentil Extrudates

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Nikolay Penov ◽  
Todorka Petrova ◽  
Milena Ruskova ◽  
Nesho Toshkov ◽  
Nikolay Menkov
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Processing Conditions ◽  
Moisture Contents ◽  
Moisture Sorption Isotherms ◽  
The Relationship

Abstract The equilibrium moisture contents (EMC) were determined for lentil extrudates produced under different processing conditions at 25°C and eight relative humidity (RH) in the range of 0.113 – 0.902. It was established that for the ten extruded samples the EMC values at the same RH were not statistically equal. Four models – Chung-Pfost, Halsey, Oswin, and Henderson equations were applied for analyzing the experimental data. The Oswin model was most suitable for describing the relationship between the EMC and RH.

Dynamic moisture sorption and hygroexpansion of Populus euramericana Cv. under two cyclic hygrothermal conditions

Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1191-1199 ◽  
Author(s):  
Tiantian Yang ◽  
Erni Ma ◽  
Jianhui Zhang
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Environmental Conditions ◽  
Moisture Sorption ◽  
Longitudinal Direction ◽  
Measured Data ◽  
Populus Euramericana ◽  
Dimensional Changes ◽  
Unit Change ◽  
Condition B

Abstract Poplar (Populus euramericana Cv.) specimens, 20 mm in radial (r) and tangential (t) directions with thicknesses of 4 mm and 10 mm along the longitudinal direction, were subjected to cyclic environmental conditions, in the course of which the relative humidity (RH) changed sinusoidally between 75% and 45% at 20°C (condition A), or the temperature (T) was changed sinusoidally within 5–35°C at 60% RH (condition B). Moisture content (MC), as well as the t- and r-dimensional changes were measured as a response to the dynamic environmental conditions. The measured data also changed sinusoidally but they lagged behind the triggering original RH or T data. This effect was much higher under condition A than under condition B. The observed equivalent RH and T changes at different ΔMCs or Δts served for comparison of the responses to RH and T, and the former were less pronounced than the latter. MC and t-dimensional changes per unit change of RH were greater than those per unit change of T but still lower than static values. In summary, the effects of dynamic RH change are larger than those of T, especially concerning MC responses compared to dimensional changes.

scholarly journals Experimental Determination of Moisture Sorption Isotherm of Fecal Sludge

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 303 ◽  
Author(s):  
Catherine Bourgault ◽  
Paul Lessard ◽  
Claire Remington ◽  
Caetano C. Dorea
Keyword(s):  
Relative Humidity ◽  
Water Distribution ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Critical Data ◽  
Moisture Sorption Isotherm ◽  
Fecal Sludge ◽  
Moisture Sorption Isotherms ◽  
Gab Model

Dewatering and drying of fecal sludge (FS) is a key treatment objective in fecal sludge management as it reduces volume (thereby reducing emptying frequency and associated transportation costs), inactivates pathogens, and is beneficial and/or necessary to resource recovery activities such as composting and combustion as fuel. However, studies on dewatering performances of FS are limited. The physical water distribution of such matrices is not fully understood, limiting the progress in the development and optimization of FS dewatering technologies. The objective of this study is to present a gravimetric method intended to assess the dewatering characteristics and associated modelling of FS through moisture sorption isotherms. Samples were placed in airtight jars containing different saturated salt (NaOH, CaCl2, NaCl, KCl, K2SO4) solutions to reproduce a range of relative humidity values (6 to 97%). Results confirmed the achievement of characteristic sigma-shaped moisture sorption isotherms with increasing moisture adsorption at higher values of relative humidity. Furthermore, experimental data best fit the three-parameter Guggenheim–Anderson–de Boer (GAB) model. This method can be replicated to contribute critical data about the characterization of fecal sludge, a seriously under-researched matrix.

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