scholarly journals The O-factor: using the H-factor concept to predict the outcome of organosolv pretreatment

2021 ◽  
Author(s):  
Prajin Joseph ◽  
Mihaela Tanase Opedal ◽  
Størker T. Moe
Keyword(s):  
Activation Energy ◽  
Linear Relationship ◽  
Total Solid ◽  
Kraft Pulping ◽  
Organosolv Pretreatment ◽  
Good Linear ◽  
Individual Biomass ◽  
Linear Fit ◽  
The Individual ◽  
P Factor

AbstractThe H-factor, a parameter used extensively to analyze and predict the outcome of kraft pulping, is applied to organosolv pretreatment. The total solid yield after organosolv pretreatment fits well with the H-factor. The concept has been extended to apply to the individual biomass polymers using unique values for the activation energy for the depolymerization of the individual biomass polymers, giving the O-factor concept analogous to the P factor used for analyzing prehydrolysis kinetics. The results showed a linear relationship between ln(L0/L) and O-factor at an activation energy of 96 kJ/mol. The best linear fit for mannan and xylan degradation was obtained at O-factor activation energies of 104 kJ/mol and 142 kJ/mol, respectively, and the formation of furfural and 5-HMF gave a good linear fit using an O-factor activation energy of 150 kJ/mol. The O-factor is thus a useful concept for analyzing organosolv pretreatment when the temperature during pretreatment is not constant.

SPATIAL DISPERSION AND SEQUENTIAL SAMPLING OF THE POTATO APHID, MACROSIPHUM EUPHORBIAE (HOMOPTERA: APHIDIDAE), ON PROCESSING-TOMATOES IN OHIO

1984 ◽  
Vol 116 (8) ◽  
pp. 1069-1075 ◽  
Author(s):  
Gregory P. Walker ◽  
Laurence V. Madden ◽  
Donald E. Simonet
Keyword(s):  
Linear Relationship ◽  
Spatial Dispersion ◽  
Sequential Sampling ◽  
Macrosiphum Euphorbiae ◽  
Potato Aphid ◽  
Good Linear ◽  
Mean Crowding ◽  
Linear Fit ◽  
Potato Aphids ◽  
Processing Tomatoes

AbstractSpatial dispersion of potato aphids was studied in fields of processing-tomatoes for 2 years to develop a sequential sampling scheme for the aphid. Potato aphids were found on upper, middle, and lower leaf strata in the percentages 60, 31, and 8. Dispersion was clumped, apterates more so than alates. Among-plant variance was generally greater than within-plant variance. There was a good linear relationship between mean crowding and the population mean and an excellent linear fit between log variance and log mean on all leaf strata for green and pink forms of the aphid and for alates and apterates. The log variance – log mean relationship was used as a basis for sequential sampling.

Determination of Chitosan Oligosaccharide Content by Acetylacetone Spectrophotometry Method

2012 ◽  
Vol 503-504 ◽  
pp. 543-547 ◽  
Author(s):  
Ze Ping Xu ◽  
Chuan Lun Yang ◽  
Xin Qing Zhang ◽  
Xiu Zhi Wang ◽  
Bao Sheng Huang
Keyword(s):  
Hydrochloric Acid ◽  
Linear Relationship ◽  
Regression Equation ◽  
Common Method ◽  
Chitosan Oligosaccharide ◽  
Average Recovery ◽  
Good Linear ◽  
Good Linear Relationship

Objective: To establish a common method to detect the content of chitosan oligosaccharide. Methods: Chitosan oligosaccharide was hydrolyzed completely by concentrated hydrochloric acid, and the solution was regulated into neutral with NaOH. Then, determined the absorbance in 525nm, and substituted into the regression equation to determine the results. Results: The results showed there was a good linear relationship when the concentration of chitosan oligosaccharide ranged from 0.02 mg/mL to 0.12 mg/mL, r2 = 0.999. The average recovery of chitosan oligosaccharide samples was 99.25%. Conclusion: The method is sensitive, accurate and simple. It is applied to determine of the content of chitosan oligosaccharide.

Enhancing the Thermoelectric Properties in Carbon Fiber/Cement Composites by Using Steel Slag

2013 ◽  
Vol 539 ◽  
pp. 103-107 ◽  
Author(s):  
Jun Qing Zuo ◽  
Wu Yao ◽  
Jun Jie Qin
Keyword(s):  
Carbon Fiber ◽  
Linear Relationship ◽  
Thermoelectric Power ◽  
Thermoelectric Properties ◽  
Steel Slag ◽  
Experimental Results ◽  
Cement Composites ◽  
Temperature Differential ◽  
High Concentration ◽  
Good Linear

Thermoelectric properties of steel slag-carbon fiber/cement composites were studied in this paper. The effect of steel slag content on thermoelectric properties was focused on especially. The experimental results show that the addition of steel slag leads to an increase in the positive thermoelectric power of the cabon fiber/cement composites. The highest absolute thermoelectric power of carbon fiber/cement composites was rendered as positive as 14.4µV/°C by using steel slag, which had a high concentration of holes. Beside, a good linear relationship was observed between thermoelectric power and temperature differential on the specimen.

Carbon Nanoparticle Spectrophotometric Determination of Glucose

2013 ◽  
Vol 726-731 ◽  
pp. 1453-1456
Author(s):  
Ai Hui Liang ◽  
Jing Peng ◽  
Yuan Li ◽  
Ling Ling Ye ◽  
Gui Qing Wen
Keyword(s):  
Linear Relationship ◽  
Spectrophotometric Determination ◽  
Glucose Concentration ◽  
Carbon Nanoparticles ◽  
Absorption Peak ◽  
Carbon Nanoparticle ◽  
Good Linear ◽  
Good Linear Relationship ◽  
Glucose Injection

In the presence of NaOH, glucose hydrolyze and polymerize to generate yellow carbon nanoparticles that had an absorption peak at 336 nm. Under the selected conditions, result showed the concentration of glucose have a good linear relationship between absorbance value and glucose concentration in the range of 0.0005-0.060 mol/L. This method has been used for the assay of glucose injection sample, with simplicity, rapidity, and accuracy.

scholarly journals Advanced Isoconversional Kinetic Analysis for the Elucidation of Complex Reaction Mechanisms: A New Method for the Identification of Rate-Limiting Steps

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1683 ◽  
Author(s):  
Nicolas Sbirrazzuoli
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Single Step ◽  
Thermoanalytical Techniques ◽  
Diffusion Controlled ◽  
Physical Transformation ◽  
Exponential Factors ◽  
Isoconversional Kinetic Analysis ◽  
The Individual ◽  
Rate Limiting

Two complex cure mechanisms were simulated. Isoconversional kinetic analysis was applied to the resulting data. The study highlighted correlations between the reaction rate, activation energy dependency, rate constants for the chemically controlled part of the reaction and the diffusion-controlled part, activation energy and pre-exponential factors of the individual steps and change in rate-limiting steps. It was shown how some parameters computed using Friedman’s method can help to identify change in the rate-limiting steps of the overall polymerization mechanism as measured by thermoanalytical techniques. It was concluded that the assumption of the validity of a single-step equation when restricted to a given α value holds for complex reactions. The method is not limited to chemical reactions, but can be applied to any complex chemical or physical transformation.

Research on the Physical Characteristics in Maize Deep-Bed Drying Process

2011 ◽  
Vol 314-316 ◽  
pp. 1478-1482
Author(s):  
Ye Zhang ◽  
Chang You Li ◽  
Zhi Wei Mai ◽  
Feng Ying Xu ◽  
Li Xu
Keyword(s):  
Linear Relationship ◽  
Pressure Loss ◽  
Static Pressure ◽  
Physical Characteristics ◽  
Test Stand ◽  
Thermal Engineering ◽  
Drying Process ◽  
Good Linear ◽  
Good Linear Relationship ◽  
The Relationship

In order to investigate the static pressure loss of the maize deep-bed drying related to the ratio of air flux to grain mass, the experiments based on the theory of thermal engineering and deep-bed drying were engaged in. These experiments conducted on the ventilation test stand indicate the relationship between static pressure loss, depth of the bed, ventilative dimensions and the ratio of air flux to grain mass. The investigation results that during the drying, the static pressure loss increases related to the increased ratio of air flux to grain mass with the constant bed depth. The good linear relationship between the static pressure loss and ventilative dimensions was indicated. With the control of the constant ventilative dimensions, the static pressure loss increases related to the decreased ratio of air flux to grain mass and it will dramatically increased when the ratio of air flux to grain mass is small enough. To reduce the static pressure loss, enlarging the ventilative dimensions, reducing the thickness of the drying layer and reducing the speed of the wind will be the proper methods.

Neural Respiratory Drive during CO2 Rebreathing Assessed by a Combined Esophageal Electrode Catheter

2011 ◽  
Vol 140 ◽  
pp. 191-194
Author(s):  
Kang Xin Tan ◽  
Dong Xiao Lu ◽  
Yuan Ming Luo
Keyword(s):  
Electrical Activity ◽  
Linear Relationship ◽  
Healthy Subjects ◽  
Respiratory Drive ◽  
Transdiaphragmatic Pressure ◽  
Good Linear ◽  
Diagnosis And Management ◽  
Breathing Difficulty ◽  
End Tidal ◽  
Spontaneously Breathing

Assessment of neural respiratory drive is useful for diagnosis and management of breathing difficulty. The diaphragm is the most important muscle of respiration, therefore its electrical activity during spontaneously breathing could be used to reflect neural respiratory drive. In this study a catheter which was composed of 10 electrodes and two balloons was developed and was used to assess neural respiratory drive during CO2rebreathing in six healthy subjects. There was a good linear relationship between diaphragm EMG and end-tidal CO2(r = 0.98±0.01) during CO2rebreathing. Transdiaphragmatic pressure was also well correlated with end-tidal CO2during CO2rebreathing. We concluded that the combined catheter developed in this study can be used to assess neural respiratory drive.

Study on Preparation of Dissolving Grade Pulp and its Kinetics of Prehydrolysis

2011 ◽  
Vol 233-235 ◽  
pp. 1479-1484
Author(s):  
Ke Xin Hu ◽  
Guang Ming Zeng ◽  
Hai Chao Zhang
Keyword(s):  
Quality Standards ◽  
Kraft Pulping ◽  
Cooking Time ◽  
Bleaching Process ◽  
First Order ◽  
Pseudo First Order ◽  
P Factor ◽  
Prehydrolysis Kraft ◽  
Kinetics Of ◽  
Pulp Production

The possibilities of dissolving grade pulp production from reed were investigated in this paper. Two – stage prehydrolysis – kraft pulping and CEHA bleaching process of reed for preparation of dissolving grade pulp were studied in laboratory. The optimum cooking and bleaching conditions were found out. The mechanism and its kinetics of reed in prehydrolysis process were also discussed. The results showed that under the laboratory conditions the rate for removal of materials at about 175°C follow approximately a pseudo first order law with two distinct phrases: the bulk removal and the residual removal of the materials. The prehydrolysis-factor (P-factor) was established. The advantage of using P-factor is predict compensating adjustments in cooking time and/or temperature to give the same degree of pulping and to produce pulp with predetermined characteristics. It is found that three distinct delignification rate stages about 75% of pentosans and about 50% of lignin were removed. A CEHA four stage bleaching is used for dissolving grade pulp. Total chlorine charge in bleaching is 6% (to oven-dry pulp). The results show that all of the indices fitted the quality standards of dissolving grade pulp.

Some aspects of cis–trans-isomerization mechanisms

1968 ◽  
Vol 46 (6) ◽  
pp. 973-978 ◽  
Author(s):  
M. C. Lin ◽  
K. J. Laidler
Keyword(s):  
Activation Energy ◽  
Linear Relationship ◽  
Bond Energy ◽  
Reaction Mechanisms ◽  
Compensation Effect ◽  
Trans Isomerization ◽  
Entropy Of Activation ◽  
Partial Compensation

It is shown that there is a linear relationship between the activation energy for a thermal cis–trans isomerization and the heat of hydrogenation of the C=C bond. There is also a linear relationship between the entropy of activation and the heat of activation, there being a partial compensation effect. It is pointed out that the activation energy for these processes is very close to the π-bond energy of the C=C bond. The significance of these relationships is discussed in terms of the reaction mechanisms.

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