Use of empirical and diffusion models in the description of the process of water absorption by rice

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Joan Carlos Alves Pereira ◽  
Wilton Pereira da Silva ◽  
Renato Costa da Silva ◽  
Cleide Maria Diniz P.S. e Silva ◽  
Josivanda Palmeira Gomes
Keyword(s):  
Water Absorption ◽  
Water Immersion ◽  
Gravimetric Method ◽  
Empirical Models ◽  
Diffusion Models ◽  
Content Type ◽  
Rice Grains ◽  
Diffusion Phenomena ◽  
Kinetics Of ◽  
Over Time

PurposeTo describe water absorption by the rice grains over time, diffusion and empirical models were used. Also, an optimization software was developed in this study to determine parameters and their uncertainties for the diffusion models (LS Optimizer, for partial differential equations). Parameters (and their uncertainties) for empirical models were determined by LAB Fit Curve Fitting Software.Design/methodology/approachHeat and mass diffusion phenomena are found in various processes of technological interest, including pasteurization, drying and water immersion of agricultural products, among others. The objective of this work was to study the process of water absorption by rice grains with and without husk, using diffusion and empirical models to describe the absorption kinetics. Rice grains were immersed (approximately 10 g for each experiment) in drinking water maintained at constant temperatures of 28, 40 and 50 C. In the experiments, the water contents absorbed by rice grains over time were obtained by the gravimetric method.FindingsAmong empirical models, Peleg was the most satisfactory to describe the kinetics of water absorption by rice without husk, while the Silva et alii model had the best statistical indicators for rice with husk. It was also verified that a diffusion model with boundary condition of the first kind showed the best (or equivalent) results in the description of all processes of kinetics of water absorption by rice grains, with and without husk. For grains without husk, the effective mass diffusivities were (1.186 ± 0.045) × 10−9, (1.312 ± 0.024) × 10−9 and (2.133 ± 0.028) × 10−9 m2 min−1, for the immersion temperatures of 28, 40 and 50C, respectively. For grains with husk, diffusivities were (0.675 ± 0.011) × 10−9 and (1.269 ± 0.017) × 10−9 m2 min−1, for temperatures of 28 and 50 C, respectively.Originality/valueThis work developed a solver for the diffusion equation in cylindrical geometry and presented the LS Optimizer software developed to determine differential equation parameters through experimental data sets.

The effect of clam shell powder on kinetics of water absorption of jute epoxy composite

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hemalata Jena ◽  
Abinash Panigrahi
Keyword(s):  
Water Absorption ◽  
Environmental Conditions ◽  
Epoxy Composite ◽  
Jute Fibre ◽  
Content Type ◽  
Clam Shell ◽  
New Class ◽  
Kinetics Of ◽  
Shell Powder ◽  
Marine Waste

Purpose Here, attempts have been made to explore the possible use of Marine waste as filler materials into the bio-fibre composites. Clam shell is a type of marine waste which belongs to the class of Bivalvia. It is mainly made of aragonite crystalline polymorphs. This paper aims to develop a new class of natural fibre composite in which jute fibre as reinforcement, epoxy as matrix and clam shell, as particulate microsphere filler. The study investigates the effects of different amounts of clam shell powder on the kinetics of water absorption of jute fibre-reinforced epoxy composite. Two different environmental conditions at room temperature, i.e. distilled water and seawater, are collected for this purpose. Moisture absorption reduces when clam shell is added to the jute-epoxy composite. The curve of water absorption of jute-epoxy composites with filler loading at both environmental conditions follows as Fickian behaviour. Design/methodology/approach Hand lay-up technique to fabricate the composite – Experimental observation Findings The incorporation of Clam shell filler in jute epoxy composite modified the water absorption property of the composite. Hence the present marine waste is an potential filler in jute fibre reinforced polymer composite. Originality/value The paper demonstrates a new class hybrid composite material which uses a marine waste as important phase in the bio-fibre-reinforced composite. It is a new work submitted for original research paper.

Effect of Cross-Linking Degree on Hydrogels using Surfactant Detergent as Template

2011 ◽  
Vol 284-286 ◽  
pp. 1827-1830 ◽  
Author(s):  
Kun Chen ◽  
Qing Song Zhang ◽  
Li Chen
Keyword(s):  
Pore Structure ◽  
Water Absorption ◽  
Nonionic Surfactant ◽  
Temperature Sensitivity ◽  
Gravimetric Method ◽  
Cross Linking ◽  
Swelling Kinetics ◽  
Cross Linker ◽  
Kinetics Of

To avoid the formation of layer-pore structure and flocculation caused by the excessive introduction of nonionic surfactant detergent polyoxyethylene 20 cetyl ether (Brij58) into polyN-isopropylacrylamide/inorganic nanoclay hectorite hydrogels network (PLH hydrogels), inorganic nanoclay hectorite content, severed as physical cross-linker, was increased from 1wt% to 3wt%. The morphology, temperature- responsibility, capacity of water absorption and swelling kinetics of resulting PHL hydrogels were investigated by SEM, DSC and Gravimetric method, respectively. It was found that PLH hydrogels would keep well honeycomb-like pore with increasing hectorite content. Furthermore, PLH hydrogels exhibited good temperature sensitivity regardless of physical cross-linker content.

scholarly journals Particle size effect in the mechanically assisted synthesis of ß-cyclodextrin mesitylene sulfonate

2020 ◽  
Author(s):  
Stéphane Menuel ◽  
Sébastien Saitzek ◽  
Eric Monflier ◽  
Frédéric HAPIOT
Keyword(s):  
Solid State ◽  
Reaction Pathway ◽  
Particle Size Effect ◽  
Data Series ◽  
Modified Cyclodextrins ◽  
Diffusion Phenomena ◽  
The Impact ◽  
Kinetics Of ◽  
Over Time

Mechanically assisted synthesis of organic compounds has recently focused considerable attention as it may be unique in features to selectively orient the reaction pathway. In the continuation of our work on the synthesis of modified cyclodextrins (CDs) via mechanochemical activation, we sought to discriminate the contribution of supramolecular effects and grinding during the course of a reaction in the solid state. As such, we recently investigated the influence of the particles size of β-CD in the synthesis of β-CD mesitylene sulfonate (β-CDMts) in the solid state using a vibrating ball-mill. We were particularly interested in the role of the particles size on the kinetics of the reaction. In this study, we show that grinding β-CD reduces the particles size over time down to a limit of 167 nm. The granulometric composition remains rather invariant for grinding times over 1 h. Each type of β-CD particles reacted with mesitylene sulfonic chloride (MtsCl) to produce β-CDMts. Contrary to what could be intuitively anticipated, smaller particles did not lead to the highest conversions. The impact of grinding over the conversions was limited. Interestingly, the proportion of β-CDMts mono-substituted on the primary face significantly increased over time when the reaction was carried out in the presence of KOH as a base. The data series were confronted with kinetics models to get clues on the way the reactions proceeded. The diversity of possible models suggests that multiple mechanochemical processes can account for the syntheses of β-CDMts in the solid state. Throughout this study, we found that the reactivity depends more upon diffusion phenomena in the crystalline parts of the material than upon the increase in the surface area of the CD particles resulting from grinding.

scholarly journals Differentiation of Vegetative Cells into Spores: a Kinetic Model Applied toBacillus subtilis

2019 ◽  
Vol 85 (10) ◽  
Author(s):  
Emilie Gauvry ◽  
Anne-Gabrielle Mathot ◽  
Olivier Couvert ◽  
Ivan Leguérinel ◽  
Matthieu Jules ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Vegetative Cell ◽  
Goodness Of Fit ◽  
Fluorescent Protein ◽  
Raw Materials ◽  
Spore Formation ◽  
Vegetative Cells ◽  
Content Type ◽  
Kinetics Of ◽  
Over Time

ABSTRACTSpore-forming bacteria are natural contaminants of food raw materials, and sporulation can occur in many environments from farm to fork. In order to characterize and to predict spore formation over time, we developed a model that describes both the kinetics of growth and the differentiation of vegetative cells into spores. The model is based on a classical growth model and enables description of the kinetics of sporulation with the addition of three parameters specific to sporulation. Two parameters are related to the probability of each vegetative cell to commit to sporulation and to form a spore, and the last one is related to the time needed to form a spore once the cell is committed to sporulation. The goodness of fit of this growth-sporulation model was assessed using growth-sporulation kinetics at various temperatures in laboratory medium or in whey forBacillus subtilis,Bacillus cereus, andBacillus licheniformis. The model accurately describes the kinetics in these different conditions, with a mean error lower than 0.78 log10CFU/ml for the growth and 1.08 log10CFU/ml for the sporulation. The biological meaning of the parameters was validated with a derivative strain ofBacillus subtilis168 which produces green fluorescent protein at the initiation of sporulation. This model provides physiological information on the spore formation and on the temporal abilities of vegetative cells to differentiate into spores and reveals the heterogeneity of spore formation during and after growth.IMPORTANCEThe growth-sporulation model describes the progressive transition from vegetative cells to spores with sporulation parameters describing the sporulation potential of each vegetative cell. Consequently, the model constitutes an interesting tool to assess the sporulation potential of a bacterial population over time with accurate parameters such as the time needed to obtain one resistant spore and the probability of sporulation. Further, this model can be used to assess these data under various environmental conditions in order to better identify the conditions favorable for sporulation regarding the time to obtain the first spore and/or the concentrations of spores which could be reached during a food process.

scholarly journals Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

2020 ◽  
Vol 16 ◽  
pp. 2598-2606
Author(s):  
Stéphane Menuel ◽  
Sébastien Saitzek ◽  
Eric Monflier ◽  
Frédéric Hapiot
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Reaction Pathway ◽  
Particle Size Effect ◽  
Data Series ◽  
Diffusion Phenomena ◽  
The Impact ◽  
Kinetics Of ◽  
Over Time

The mechanically assisted synthesis of organic compounds has recently focused considerable attention as it may be unique in features to selectively direct the reaction pathway. In the continuation of our work on the synthesis of modified cyclodextrins (CDs) via mechanochemical activation, we sought to discriminate the contribution of supramolecular effects and grinding during the course of a reaction in the solid state. As such, we recently investigated the influence of the particle size of β-CD in the synthesis of β-CD mesitylene sulfonate (β-CDMts) in the solid state using a vibrating ball-mill. We were particularly interested in the role of the particle size on the kinetics of the reaction. In this study, we show that grinding β-CD reduces the particles size over time down to a limit of 167 nm. The granulometric composition remains rather invariant for grinding times over 1 h. Each type of β-CD particles reacted with mesitylenesulfonyl chloride (MtsCl) to produce β-CDMts. Contrary to what could be intuitively anticipated, smaller particles did not lead to the highest conversions. The impact of grinding on the conversion was limited. Interestingly, the proportion of β-CDMts mono-substituted on the primary face significantly increased over time when the reaction was carried out in the presence of KOH as a base. The data series were confronted with kinetics models to get insight in the way the reactions proceeded. The diversity of possible models suggests that multiple mechanochemical processes can account for the formation of β-CDMts in the solid state. Throughout the study, we found that the reactivity depended more upon diffusion phenomena in the crystalline parts of the material than on the increase in the surface area of the CD particles resulting from grinding.

scholarly journals Physical properties and water absorption kinetics of three varieties of Mucuna beans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ajibola B. Oyedeji ◽  
Olajide P. Sobukola ◽  
Ezekiel Green ◽  
Oluwafemi A. Adebo
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Rate Constant ◽  
Geometric Mean ◽  
Seed Mass ◽  
Activation Energies ◽  
Mucuna Pruriens ◽  
Absorption Kinetics ◽  
Kinetics Of ◽  
Soaking Temperature

AbstractThe physical properties and water absorption kinetics of three varieties of Mucuna beans (Mucuna pruriens, Mucuna rajada and Mucuna veracruz) were determined in this study. Physical properties including length, width, thickness, geometric mean diameter, sphericity, porosity, bulk density, area, volume and one thousand seed mass were calculated while hydration kinetics was studied by soaking Mucuna beans in water at 30 °C, 40 °C and 50 °C and measuring water uptake at 9 h interval. Peleg’s equation was used to model the hydration characteristics and Arrhenius equation was used to describe the effect of temperature on Peleg’s rate constant k1 and to obtain the activation energies for soaking. Significant variations were observed in almost all the physical properties of the different varieties, however, there were no significant differences (p < 0.05) in their thicknesses and bulk densities. The effectiveness of fit of Peleg’s model (R2) increased with increase in soaking temperature. Peleg’s rate constant k1 decreased with increase in soaking temperature while k2 increased with temperature increase. Activation energies of Mucuna pruriens, Mucuna rajada and Mucuna veracruz were 1613.24 kJ/mol, 747.95 kJ/mol and 2743.64 kJ/mol, respectively. This study provides useful information about the properties of three varieties of Mucuna beans that could be of importance to processors and engineers for process design and optimization.

scholarly journals Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Uptake ◽  
Significant Influence ◽  
Water Immersion ◽  
Water Diffusion ◽  
Polybutylene Terephthalate ◽  
Chemical Changes ◽  
Water Ingress ◽  
Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

scholarly journals Kinetics of Anti-SARS-CoV-2 Antibody Responses 3 Months Post Complete Vaccination with BNT162b2; A Prospective Study in 283 Health Workers

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1942
Author(s):  
Evangelos Terpos ◽  
Ioannis P. Trougakos ◽  
Vangelis Karalis ◽  
Ioannis Ntanasis-Stathopoulos ◽  
Sentiljana Gumeni ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Health Workers ◽  
Antibody Responses ◽  
Healthy Individuals ◽  
Younger Age ◽  
Constant Rate ◽  
Rate Of Decline ◽  
A Prospective Study ◽  
Kinetics Of ◽  
Over Time

The aim of this study was to investigate the kinetics of neutralizing antibodies (NAbs) and anti-SARS-CoV-2 anti-S-RBD IgGs up to three months after the second vaccination dose with the BNT162b2 mRNA vaccine. NAbs and anti-S-RBD levels were measured on days 1 (before the first vaccine shot), 8, 22 (before the second shot), 36, 50, and three months after the second vaccination (D111) (NCT04743388). 283 health workers were included in this study. NAbs showed a rapid increase from D8 to D36 at a constant rate of about 3% per day and reached a median (SD) of 97.2% (4.7) at D36. From D36 to D50, a slight decrease in NAbs values was detected and it became more prominent between D50 and D111 when the rate of decline was determined at −0.11 per day. The median (SD) NAbs value at D111 was 92.7% (11.8). A similar pattern was also observed for anti-S-RBD antibodies. Anti-S-RBDs showed a steeper increase during D22–D36 and a lower decline rate during D36–D111. Prior COVID-19 infection and younger age were associated with superior antibody responses over time. In conclusion, we found a persistent but declining anti-SARS-CoV-2 humoral immunity at 3 months following full vaccination with BNT162b2 in healthy individuals.

scholarly journals kinetics of anti-SARS-CoV-2 antibodies over time. Results of 10 month follow up in over 300 seropositive Health Care Workers

2021 ◽  
Author(s):  
Jose Felipe Varona ◽  
Rodrigo Madurga ◽  
Francisco Peñalver ◽  
Elena Abarca ◽  
Cristina Almirall ◽  
...  
Keyword(s):  
Health Care ◽  
Health Care Workers ◽  
Care Workers ◽  
Kinetics Of ◽  
Over Time

scholarly journals Rough diamonds in emerging markets: legacy, competitiveness, and sustained high performance

2019 ◽  
Vol 26 (3) ◽  
pp. 363-386
Author(s):  
Seung Ho Park ◽  
Gerardo R. Ungson
Keyword(s):  
Human Capital ◽  
Emerging Markets ◽  
High Performance ◽  
Core Competencies ◽  
Market Potential ◽  
Government Support ◽  
Screening Tests ◽  
Institutional Voids ◽  
Content Type ◽  
Over Time

Purpose The purpose of this paper is to uncover the underlying drivers of sustained high performing companies based on a field study of 127 companies in Brazilian, Russian, Indian and Chinese (BRIC) and Association of Southeast Asian Nations (ASEAN) emerging markets. Understanding these companies provides a complementary way of appraising the growth, development and transformation of emerging markets. The authors synthesize the findings in an overarching framework that covers six strategies for building and sustaining legacy that leads to the succession of intergenerational wealth over time: overcoming institutional voids, inclusive markets, deepening localization, nurturing government support, building core competencies and harnessing human capital. The authors relate these strategies to different levels of development using Prahalad and Hart’s BOP framework. Design/methodology/approach This study examines the underlying drivers of sustained high-performance companies based on field studies from an initial set of 105,260 BRIC companies and close to 500 companies in ASEAN. The methods employed four screening tests to arrive at a selection of the highest-performing firms: 70 firms in the BRIC nations and 58 firms from ASEAN. Following the selection, the authors constructed cases using primary interviews and secondary data, with the assistance of Ernst & Young and with academic colleagues in Manila. These studies were originally conducted in two separate time periods and reported accordingly. This paper synthesizes the findings of these two studies to arrive at an extended integrative framework. Findings From the cases, the authors examine six strategies for building and sustaining legacy that lead to high performance over time: overcoming institutional voids, creating inclusive markets, deepening localization, nurturing government support, building core competencies and harnessing human capital. To address the evolving state of institutional voids in these countries, the authors employ similar methods to hypothesize the placement of these strategies in the context of the world economic pyramid, initially formulated as the “bottom of the pyramid” framework. Originality/value This paper synthesizes and extends the authors’ previous works by proposing the concept of legacy to describe the emergence and succession of local exemplary firms in emerging markets. This study aims to complement extant measures of nation-growth based primarily on GDP. The paper also extends the literature on institutional voids in shifting the focus from the mix of voids to their evolving state. Altogether, the paper provides a complementary narrative on assessing the market potential of emerging markets by adopting several categories of performance.

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