scholarly journals Novel Kinetic Models of Xylan Dissolution and Degradation during Ethanol Based Auto-Catalyzed Organosolv Pretreatment of Bamboo

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1149 ◽  
Author(s):  
Jing Liu ◽  
Zhenggang Gong ◽  
Guangxu Yang ◽  
Lihui Chen ◽  
Liulian Huang ◽  
...  

Due to the invalidity of traditional models, pretreatment conditions dependent parameter of susceptible dissolution degree of xylan (dX) was introduced into the kinetic models. After the introduction of dX, the dissolution of xylan, and the formation of xylo-oligosaccharides and xylose during ethanol based auto-catalyzed organosolv (EACO) pretreatments of bamboo were well predicted by the pseudo first-order kinetic models (R2 > 97%). The parameter of dX was verified to be a variable dependent of EACO pretreatment conditions (such as solvent content in pretreatment liquor and pretreatment temperature). Based on the established kinetic models of xylan dissolution, the dissolution of glucan and the formation of degradation products (furfural and acetic acid) could also be empirically modeled (R2 > 97%). In addition, the relationship between xylan and lignin removal can provide guidance for alleviating the depositions of lignin or pseudo-lignin. The parameter of dX derived novel kinetic models can not only be used to reveal the multi-step reaction mechanisms of xylan, but also control the final removal of main components in bamboo during EACO pretreatments, indicating scientific and practical significance for governing the biorefinery of woody biomass.

EMJ Radiology ◽  
2020 ◽  
Author(s):  
Filippo Pesapane

Radiomics is a science that investigates a large number of features from medical images using data-characterisation algorithms, with the aim to analyse disease characteristics that are indistinguishable to the naked eye. Radiogenomics attempts to establish and examine the relationship between tumour genomic characteristics and their radiologic appearance. Although there is certainly a lot to learn from these relationships, one could ask the question: what is the practical significance of radiogenomic discoveries? This increasing interest in such applications inevitably raises numerous legal and ethical questions. In an environment such as the technology field, which changes quickly and unpredictably, regulations need to be timely in order to be relevant.  In this paper, issues that must be solved to make the future applications of this innovative technology safe and useful are analysed.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1055
Author(s):  
Gulenay Guner ◽  
Dogacan Yilmaz ◽  
Ecevit Bilgili

This study examined the impact of stirrer speed and bead material loading on fenofibrate particle breakage during wet stirred media milling (WSMM) via three kinetic models and a microhydrodynamic model. Evolution of median particle size was tracked via laser diffraction during WSMM operating at 3000–4000 rpm with 35–50% (v/v) concentration of polystyrene or zirconia beads. Additional experiments were performed at the center points of the above conditions, as well as outside the range of these conditions, in order to test the predictive capability of the models. First-order, nth-order, and warped-time kinetic models were fitted to the data. Main effects plots helped to visualize the influence of the milling variables on the breakage kinetics and microhydrodynamic parameters. A subset selection algorithm was used along with a multiple linear regression model (MLRM) to delineate how the breakage rate constant k was affected by the microhydrodynamic parameters. As a comparison, a purely empirical correlation for k was also developed in terms of the process/bead parameters. The nth-order model was found to be the best model to describe the temporal evolution; nearly second-order kinetics (n ≅ 2) was observed. When the process was operated at a higher stirrer speed and/or higher loading with zirconia beads as opposed to polystyrene beads, the breakage occurred faster. A statistically significant (p-value ≤ 0.01) MLRM of three microhydrodynamic parameters explained the variation in the breakage rate constant best (R2 ≥ 0.99). Not only do the models and the nth-order kinetic–microhydrodynamic correlation enable deeper process understanding toward developing a WSMM process with reduced cycle time, but they also provide good predictive capability, while outperforming the purely empirical correlation.


Apeiron ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jan Maximilian Robitzsch

Abstract This paper examines the classification of desires that the Epicureans offer in their writings. It surveys the extant textual evidence for the classification and discusses the relationship between natural and necessary, natural and unnecessary, and unnatural and unnecessary desires. It argues that while the practical significance of the Epicurean classification is clear, which desires fall into which class is not. The paper suggests the reason for this may be that the Epicureans acknowledge some variability in their concept of human nature, arguing for a functional reading of the Epicurean classification of desires.


2012 ◽  
Vol 524-527 ◽  
pp. 2474-2481
Author(s):  
Zhi Gang Huang ◽  
Jiao Ling Xie ◽  
Wen Ping Wu

Carbon emissions permits has its own particularity,and with the development of carbon finance,carbon emissions permits possess the commodity attributes and financial attributes.So its price isn’t determined only by the relationship of commodity supply and demand,but also affected by a variety of factors.But because the transaction data is not available,so the pricing of the carbon emissions permits can not really consider from the angle of the influencing factors of price.Therefore, this paper is on the basis of previous studies using mathematical tools and introducing the option pricing mechanism to study th pricing of China's carbon emissions permits basing on carbon emissions,which is designed for providing reference on the pricing of China's carbon emissions,being of both theoretical and practical significance.


2011 ◽  
Vol 243-249 ◽  
pp. 4956-4959
Author(s):  
Jian Chao Hao ◽  
Hui Fen Liu ◽  
Dong Ling Wei ◽  
Li Jun Shi ◽  
Jun Li Li ◽  
...  

The relationship between formaldehyde emission and time was researched and a mathematical model was developed which describes the variation of formaldehyde with time in the airtight chamber. It was found that high quality composite floor was in line with 0-order kinetic equation and low quality composite floor was in line with 1-order kinetic equation. Besides, the effect of activated carbon adsorption on formaldehyde was studied and the result showed that activated carbon had poor adsorption on formaldehyde for weak van der waals force.


2014 ◽  
Vol 79 (3) ◽  
pp. 361-377 ◽  
Author(s):  
Huan-Yan Xu ◽  
Wei-Chao Liu ◽  
Shu-Yan Qi ◽  
Yan Li ◽  
Yuan Zhao ◽  
...  

Kinetics and optimization on the discoloration of an active commercial dye, Argazol Blue BFBR (ABB) by heterogeneous Fenton-like reaction catalyzed by natural schorl were investigated in this study. Kinetic investigations revealed that the first-order kinetic model was more favorable to describe the discoloration of ABB at different reaction conditions than the second-order and Behnajady-Modirshahla-Ghanbery models. The relationship between the reaction rate constant k and reaction temperature T followed the Arrhenius equation, with the apparent activation energy Ea of 51.31kJ?mol-1. The central composite design under the response surface methodology was employed for the experimental design and optimization of the ABB discoloration process. The significance of a second order polynomial model for predicting the optimal values of ABB discoloration was evaluated by the analysis of variance and 3D response surface plots for the interactions between two variables were constructed. Then, the optimum conditions were determined.


TECHNOLOGY ◽  
2015 ◽  
Vol 03 (02n03) ◽  
pp. 80-83
Author(s):  
Mark Polikovsky ◽  
Eshel Ben-Jacob ◽  
Alin Finkelshtein

Cellulose hydrolysis has many industrial applications such as biofuel production, food, paper and textile manufacture. Here, we present a novel approach to cellulose hydrolysis using a consortium of motile bacteria, Paenibacillus vortex, that can swarm on solid medium carrying a non-motile recombinant E. coli cargo strain expressing the β-glucosidase and cellulase genes that facilitate the hydrolysis of cellulose. These two species cooperate; the relationship is mutually beneficial: the E. coli is dispersed over long distances, while the P. vortex bacteria gain from the supply of cellulose degradation products. This enables the use of such consortia in this area of biotechnology.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Svetlana D. Gurieva ◽  
Oksana V. Zashchirinskaia

Purpose The purpose of this paper is to investigate the relationship of values with individual economic behaviour, identifies the correlation between personality values that are conditioned upon the culture, and evaluations of economic behaviour situations on the example of Russian culture. Design/methodology/approach This study involved 222 people of Russian nationality, young entrepreneurs employed in the commercial field, developing their own business. The following methods were used in the study: the methodology for measuring the values of an individual and cultural level; Melbourne Decision Making Questionnaire, a scenario methodology for economic behaviour, which is a short behavioural scenario (model of behaviour), taken from real life. The statistical processing of experimental data was carried out using the IBM SPSS Statistics Version 21 software package. Findings The values with correlated progressive and regressive economic forms of behaviour were identified for modern Russian society. The correlation of factors with progressive and regressive economic behaviour was also identified. Practical implications The practical significance of the study lies in the possibility of applying the results obtained not only in the system of economic education but also in programs to support the business activity of young entrepreneurs. Originality/value The value of this study is determined by the fact that it can be placed in a broader context of research into the relationship between the levels of human consciousness and his behaviour.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Chih Ming Ma ◽  
Yung Shuen Shen ◽  
Po Hsiang Lin

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.


Author(s):  
S.A. Seliverstov ◽  

The article discusses the issue of the formation of professionally important qualities (PIQ) in future military aviation navigators in the educational environment of a military university. The goal is to substantiate the activity approach as a practice-oriented basis for the formation of professional qualities in cadets-navigators. A review and analysis of scientific research, publications is carried out, allowing to discover the significance of the activity approach as a methodological direction of research. The methodological basis of the research is the provisions of the activity approach, which are used as the basis for the development and formation of the PIQ among cadets-navigators in the process of a practice-oriented educational process. The description of the results is associated with the characteristics of the content and organization of the professional activity of cadets-navigators in the process of implementation of industrial practice in the form of flight training. Using the activity approach, the main components of the activities of flight instructors, teachers and cadets-navigators are considered, from a unified methodological point of view, and thus the nature of their interaction is revealed. Emphasis have been determined that need to be paid attention to in the course of pedagogical activity on the formation of professional qualities among cadets-navigators. A definition is given and pedagogical technologies are proposed for the formation of professional experience and professional qualities in a future specialist in the context of a practice-oriented pedagogical process. The relationship between the experience gained by the trainee in the practice-oriented pedagogical process and the formation of professionally important personality traits of a specialist is considered. The main goals and objectives for the formation of the necessary professional qualities of cadetsnavigators during flight training have been determined. At the entrance of each stage of flight training, technologies are determined aimed at rational and purposeful impact on the student in order to develop competencies and personal qualities. Recommendations are offered to teachers and instructors to improve the efficiency of development and formation among cadets-navigators of the PIQ.


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