Role of surface molecular environment and amorphous content in moisture sorption behavior of milled Terbutaline Sulphate

Abstract. Understanding of moisture sorption isotherms (MSI) is critical for predicting the stability of wood during handling, transport, and storage. The aim of this study was to evaluate the adsorption and desorption isotherm characteristics of high-pressure (HP) treated paulownia wood and to identify the best-fitting model to describe its sorption behavior. The equilibrium moisture contents (EMCs) of HP-treated paulownia wood were obtained using a static gravimetric method under different storage conditions: three temperatures (20°C, 30°C, and 40°C) and five water activity (aw) levels (0.32 to 0.95). Results showed that HP parameters did not significantly affect the MSI trend of treated groups. Eight modified models (modified Chung-Pfost, modified Henderson, modified Oswin, modified Halsey, Chen-Clayton, Guggenheim-Anderson-de Boer (GAB), simply modified GAB, and Peleg) were fitted to the experimental data. The Chen-Clayton model (temperature-dependent) produced randomized residuals and the best prediction performance for both adsorption and desorption among all models. Net isosteric heat of adsorption and desorption decreased from 7.55 to 4.84 kJ mol-1 and from 18.1 to 12.2 kJ mol-1, respectively, with an increase in EMC from 7.5% to 10%. The isosteric temperature (Tß) was 352 K for adsorption and 335 K for desorption, between which all the adsorption and desorption reactions proceeded at the same rate. All thermodynamic functions were adequately characterized by a power law model. Keywords: Equilibrium moisture content, High-pressure treatment, Modeling, Moisture sorption isotherm, Paulownia wood, Temperature, Thermodynamic analysis.

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Moisture Sorption Behavior and Thermodynamic Properties of Gulabjamun Mix

Journal of Food Processing and Preservation ◽

10.1111/jfpp.12199 ◽

2013 ◽

Vol 38 (6) ◽

pp. 2192-2200 ◽

Cited By ~ 9

Author(s):

Heartwin A. Pushpadass ◽

F. Magdaline Eljeeva Emerald ◽

Bharat Chaturvedi ◽

K. Jayaraj Rao

Keyword(s):

Thermodynamic Properties ◽

Moisture Sorption ◽

Sorption Behavior

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Moisture Sorption Behavior, and Effect of Moisture Content and Sorbitol on Thermo-Mechanical and Barrier Properties of Pectin Based Edible Films

International Journal of Food Engineering ◽

10.2202/1556-3758.1137 ◽

2007 ◽

Vol 3 (4) ◽

Cited By ~ 4

Author(s):

Neda Maftoonazad ◽

Hosahalli S. Ramaswamy ◽

Michele Marcotte

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Moisture Content ◽

Moisture Sorption ◽

Water Vapor Permeability ◽

Edible Films ◽

Vapor Permeability ◽

Sorption Behavior ◽

Intermediate Water ◽

Moisture Contents

The moisture sorption behavior of pectin films formulated with different sorbitol content was evaluated and films with different equilibrium moisture contents were obtained. Different models were used to describe the moisture sorption isotherms (MSI) of pectin films, sorbitol and pectin powder. Based on changes observed in MSI, sorbitol was found to strongly interact with pectin polymers. Incorporation of sorbitol in pectin films resulted in lower equilibrium moisture contents at low to intermediate water activities (aw), but much higher moisture contents at aw > 0.53. Estimates of monolayer moisture values (1.53 3.81 g H2O kg-1 solids) were obtained by the application of Guggenheim-Anderson-DeBoer (GAB) model. A differential mechanical analyzer (DMA) was used for mechanical properties of formulated films while a differential scanning calorimeter (DSC) was used for thermal properties and glass transition temperature (Tg). With both DMA and DSC tests, the strong plasticizing action of water and sorbitol was evident. Tg vs. moisture content data were successfully fitted to the Fox empirical model. Multi-frequency DMA measurements provided estimates for the apparent activation energy (Ea) of the second glass transition in the range of 131-184 kJ/mol; the values for Ea decreased with increasing sorbitol concentration. Water vapor permeability (WVP) and mechanical properties of the films were also analyzed under varying sorbitol and moisture contents. Increasing moisture or addition of sorbitol to pectin films increased the elongation at break, but decreased the tensile strength, modulus of elasticity and Tg, and increased WVP of the films.

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A Mathematical Model Forecasting HF Adsorption onto Cu-Coated Wafers as a Function of the Airborne Concentration and Moisture

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.255.323 ◽

2016 ◽

Vol 255 ◽

pp. 323-328

Author(s):

Fernando Herrán ◽

Hervé Fontaine ◽

Paola González-Aguirre ◽

Carlos Beitia ◽

Jim Ohlsen ◽

...

Keyword(s):

Mathematical Model ◽

Surface Concentration ◽

Threshold Concentration ◽

Sorption Behavior ◽

Yield Losses ◽

Airborne Concentration ◽

Adsorption Desorption

In order to better understand and model the whole sorption behavior of the HF when in contact with a Cu surface inside a FOUP and thus control the related yield losses, Cu-coated wafers have been exposed to varying HF (ppbv) and H2O (% RH) airborne concentrations. These experiments have yielded a HF-Cu sorption empirical-mathematical model that may be used as an industrial tool for queue-time or fluoride surface concentration predictions. Besides, the formation of CuF2 only in case of corrosion is evidenced by the XPS measurements whereas the key role of the H2O is further confirmed by the desorption experiments. The H2O retained by the surface is actually responsible for promoting the HF adsorption/desorption onto/from Cu and enables a HF threshold concentration that separates the two well differenced uptake regimes; adsorption and corrosion.

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Physicochemical, functional and antinutritional properties of starches from Caladium bicolor and Dioscorea dumentorum

European Journal of Chemistry ◽

10.5155/eurjchem.10.3.228-233.1833 ◽

2019 ◽

Vol 10 (3) ◽

pp. 228-233

Author(s):

Ifiok Nseobong Uwem ◽

Basil Nse Ita

Keyword(s):

Ir Spectra ◽

Functional Properties ◽

Exposure Time ◽

Wild Species ◽

Moisture Sorption ◽

Absorption Capacity ◽

Sorption Behavior ◽

Oil Absorption ◽

Crude Lipid ◽

Food Applications

Starch samples from the wild species of cocoyam (Caladium bicolor (Aiton) Vent.) and three leaf yam (Dioscorea dumentorum (Kunth) Pax.) found abundantly in the south and eastern regions of Nigeria, were characterized for their physicochemical, functional and antinutrient properties. C. bicolor had higher amylose (17.68%), carbohydrate (83.57%) and ash (2.85%) than D. dumentorum. Moisture, crude lipid, protein and fibre ranged between 7.56 to 10.29%, 0.12 to 0.15%, 0.11 to 0.13%, and 2.85 to 3.39%, respectively. The starches exhibited promising functional properties with D. dumentorum having higher dispersibility (64.85%), solubility (73.99%) and oil absorption capacity (2.15 g/g). Onset (To), midpoint (Tm), and conclusion (Tc) gelatinization temperatures ranged between 63 to 79 °C. Peak, breakdown and setback viscosity were higher in D. dumentorum than C. bicolor. Moisture sorption behavior indicated increased hygroscopy with exposure time. The starches had high antinutrient levels, with D. dumentorum having higher levels of HCN and oxalates. In addition, infrared (IR) spectra of both starches were similar. Taken together, these properties suggest the suitability of these starches for non-food applications due to their high antinutrient contents.

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