Experimental Determination and Modeling of Desorption Isotherms of the Tomato "Lycopersicum esculentum"

2021 ◽  
pp. 24-31
Author(s):  
Roland Lankouande ◽  
G. Gilbert Nana ◽  
Souleymane Ouedraogo ◽  
Kalifa Palm ◽  
Frédéric Ouattara ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Experimental Studies ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Storage Conditions ◽  
Market Place ◽  
Desorption Isotherms ◽  
Final Water Content ◽  
The Stability

The aim of this work is to make a contribution to the drying of tomatoes. The purpose of this contribution is the experimental determination of the desorption isotherms of a variety of tomato (one of the most widespread on the Burkinabe market place) using the static gravimetric method at temperatures of 25°C, 40°C and 50°C. It is more specifically a question of validating a theoretical model based on these experimental studies. Sorption isotherms allow us to have information to establish the stability of food products and their storage conditions. These isotherms are curves which give valuable information on the hygroscopic balance of a product because they allow to know its range of stability after drying by determining the final water content.

scholarly journals Experimental Determination and Modeling of the Moisture-Sorption Isotherms and Isosteric Heat of Tobacco Leaves

2021 ◽  
Vol 20 (5) ◽  
pp. 269-277
Author(s):  
Foullanine Meriama ◽  
Bennaceur Said ◽  
Loumani Akil ◽  
Mediani Ahmed ◽  
Moungar Houcine ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Experimental Determination ◽  
Water Content ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Nicotiana Tabacum L ◽  
Desorption Isotherms ◽  
Adsorption Desorption

During a forced convection sun drying and storage operation, the equilibrium water content of a product to be dried is critical. These figures are frequently derived using isothermal sorption curves. The calculation of isotherms is a necessary step in determining the distribution and intensity of water connections in products. for that this paper concentrates on the experimental determination of the adsorption-desorption isotherms for various temperatures (40, 50, and 60℃) of the Nicotiana Tabacum L plants. From which we had established the relationship between the water activity and the water content in the product. However, the aforementioned determination was carried out by the static gravimetric method. Eight saturated salt solutions have been utilized in applications such as (KOH, KCl, MgCl2, MgNO3, K2CO3, BaCl2, K2SO4, and NaCl). Hygroscopic equilibrium was completed after 13 days for temperature 40℃, 11 days for 50℃, and 9 days for 60℃. The overall experimental sorption curves are summarized by six models (HENDERSON, modified HALSEY, OSWIN, GAB, modified BET, and PELEG). The sorption isotherms built using the Clausius–Clapeyron equation were used to determine the net isosteric temperatures of desorption and adsorption of Nicotiana Tabacum L. The results for the adsorption-desorption isotherms found are type III according to IUAPC. Following the smoothing of the experimental results by different used models, it was found that the models of GAB and Peleg allow having the lowest mean relative errors and correlation coefficient.

scholarly journals Modelling the Water Sorption Isotherms of Warionia Saharae and determination of sorption heats and drying kinetics

2018 ◽  
Author(s):  
Fedol Amel ◽  
A. Cheriti
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Storage Conditions ◽  
Drying Kinetics ◽  
Equilibrium Water Content ◽  
Clapeyron Equation

The hygroscopic equilibrium of Warionia saharae was studied, which allowed getting an idea of ​​the equilibrium water content relative to a given humidity. The results of this study made it possible to have the sorption curves. The results of this study made it possible to obtain the sorption curves necessary for know the storage conditions of the plant and the study of its drying kinetics. The static gravimetric method was used to determine sorption isotherms of Warionia saharae leaves at 30and 40 ◦C and in the range of water activity varying from 0.063 to 0.898.  The Gab, Peleg models was found to be the most suitable for describing the sorption curves. The isosteric heat calculated by applying the Clausius–Clapeyron equation .The desorption isosteric heat was higher than the isosteric heat of adsorption and both decreased continuously with increasing of the equilibrium moisture content. The experimental results obtained allowed us to determine the temporal evolution of the drying kinetics as a function of the moisture content. The curve of the evolution of the water content as a function of time shows the absence of the phases product temperature and constant drying rate Keywords: Sorption isotherm, isosteric heats, modelling, kinetics, Warionia saharae.  

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Moisture Sorption Isotherms and Isosteric Heats of Sorption of High-Pressure Treated Paulownia Wood under Different Storage Conditions

2019 ◽  
Vol 62 (1) ◽  
pp. 105-114
Author(s):  
Xiuping Jiang ◽  
Xiuping Jiang ◽  
Huanhuan Li ◽  
Hosahalli S. Ramaswamy ◽  
Songming Zhu ◽  
...  
Keyword(s):  
High Pressure ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Storage Conditions ◽  
Sorption Behavior ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Paulownia Wood

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.

Experimental Studies of Force Systems on Steered Agricultural Tyres

1966 ◽  
Vol 181 (1) ◽  
pp. 133-148 ◽  
Author(s):  
P. A. Taylor ◽  
R. Birtwistle
Keyword(s):  
Experimental Determination ◽  
Experimental Studies ◽  
Soil Surface ◽  
Slip Angle ◽  
Vertical Load ◽  
Force Systems

The paper reports the experimental determination of the force systems acting on free-rolling 7–50 times 16 agricultural tyres, measured with a six-component suspension of the test wheel. Multivariate experimentation techniques were used involving five variables: slip angle, camber, vertical load, tyre pattern and land or furrow operation. The results are presented as three force and three moment components; other methods of representation are discussed briefly. Although the side or cornering force depends on many factors, particularly the soil surface, and is therefore difficult to predict, it is suggested that the draught force (i.e. resistance in the direction of motion) can be expressed as a function of slip for all surfaces.

Effect of storage of plasma and serum on enzymatic determination of non-esterified fatty acids

2001 ◽  
Vol 38 (3) ◽  
pp. 252-255 ◽  
Author(s):  
Luis García Menéndez ◽  
Ana L Fernández ◽  
Alfredo Enguix ◽  
Constanza Ciriza ◽  
Juan Amador
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Storage Conditions ◽  
The Other ◽  
Specific Reference ◽  
Enzymatic Method ◽  
Esterified Fatty Acids ◽  
Enzymatic Determination ◽  
The Stability

Many contradictory results have been published on the stability of total non-esterified fatty acids in blood, plasma and serum under different storage conditions. The present study was undertaken to investigate the stability of non-esterified fatty acids, measured with an enzymatic method, in samples of EDTA-treated plasma and serum under different temperature conditions. We conclude that EDTA-treated plasma and serum can both be used for analysis. Specific reference values should be established depending on the type of sample chosen. Samples that cannot be analysed immediately can be stored at -20°C for at least 14 days without significant changes in the concentration of total non-esterified fatty acids. None of the other storage conditions and periods studied are suitable for the measurement of non-esterified fatty acid concentration.

The pressure dependence of the dehydration of gypsum to bassanite

1987 ◽  
Vol 51 (361) ◽  
pp. 453-457 ◽  
Author(s):  
J. D. C. McConnell ◽  
D. M. Astill ◽  
P. L. Hall
Keyword(s):  
Elevated Temperature ◽  
Experimental Determination ◽  
Volume Change ◽  
Pressure Dependence ◽  
Thermodynamic Data ◽  
Dehydration Reaction ◽  
Temperature And Pressure ◽  
The Stability ◽  
Very High

AbstractA new experimental determination of the stability relationships for the dehydration of gypsum to the hemihydrate mineral bassanite at elevated temperature and pressure is described. The experimental method used depends on the observation of very small changes in pressure on the onset of reaction due to the potential volume change in the reaction. The technique yields P-T data of very high precision for this dehydration reaction, and the method is likely to be of use for other reactions. The experimental P-T results have been compared with those calculated from existing thermodynamic data for this reaction.

scholarly journals Evaluation of Synthetic Cannabinoid Metabolites in Human Blood in the Absence of Parent Compounds: A Stability Assessment

2020 ◽  
Author(s):  
Alex J Krotulski ◽  
Sandra C Bishop-Freeman ◽  
Amanda L A Mohr ◽  
Barry K Logan
Keyword(s):  
Accurate Determination ◽  
Synthetic Cannabinoids ◽  
The United States ◽  
Storage Conditions ◽  
Synthetic Cannabinoid ◽  
Blood Samples ◽  
Flight Mass Spectrometry ◽  
Acid Metabolites ◽  
The Stability

Abstract Synthetic cannabinoids represent a chemically diverse class of novel psychoactive substances (NPS) responsible for large analytical and interpretative challenges for forensic toxicologists. Between 2016 and 2019, the three most prevalent synthetic cannabinoids in the United States were MMB-FUBINACA (FUB-AMB), 5F-MDMB-PINACA (5F-ADB) and 5F-MDMB-PICA, based on results from seized drug and toxicology testing. In 2018, accurate determination of synthetic cannabinoid positivity was brought into question as it was determined that the metabolites of these drug species were present in the absence of parent compounds in forensically relevant blood samples. During this study, the stability of MMB-FUBINACA, 5F-MDMB-PINACA and 5F-MDMB-PICA was evaluated, as well as the characterization of breakdown products. A liquid–liquid extraction method was assessed for recovery of basic parent compounds and acidic metabolites and deemed fit for use in this study. Analysis was performed by liquid chromatography–quadrupole time-of-flight mass spectrometry (LC–QTOF-MS) using a SCIEX TripleTOF® 5600+. All three synthetic cannabinoids were found to be unstable when stored in blood at either room temperature or refrigerated; all analytes were considerably more stable when stored in the freezer. All three synthetic cannabinoids degraded to their respective butanoic acid metabolites: MMB-FUBINACA 3-methylbutanoic acid, 5F-MDMB-PINACA 3,3-dimethylbutanoic acid and 5F-MDMB-PICA 3,3-dimethylbutanoic acid. All three of these metabolites were studied and determined to be stable in blood at all storage conditions. Considering these results, our laboratory continued testing for synthetic cannabinoid metabolites in blood samples and found 83 positives (21%) for only a synthetic cannabinoid metabolite. A case report is presented herein where 5F-MDMB-PINACA 3,3-dimethylbutanoic acid was identified in the absence of 5F-MDMB-PINACA. Forensic toxicologists should be aware of the results of this study as they directly impact analytical consideration for test development and implementation, as well as interpretation of findings.

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