scholarly journals Adsorption Potential Theory for Description of n-Butane Adsorption on Activated Carbon

2017 ◽  
Vol 71 (2) ◽  
pp. 1
Author(s):  
Mieczysław Bałys ◽  
Jakub Szczurowski ◽  
Leszek A. Czepirski ◽  
Marek Kochel
Keyword(s):  
Potential Theory ◽  
Active Carbon ◽  
Characteristic Curve ◽  
Thermodynamic Characteristics ◽  
Relative Pressure ◽  
Thermal Equation ◽  
Gaseous Mixtures ◽  
Equilibrium Behavior ◽  
Wide Range ◽  
Adsorption Potential Theory

Potential theory of adsorption was used for description of adsorption isotherms of n-butane on microporous active carbon. It was shown that characteristic curve of adsorption can be treated as specific form of thermal equation of adsorption giving the possibility to calculate and predict both equilibrium and thermodynamic characteristics of adsorption in wide range of temperature and relative pressure. The results can be used for the design of adsorption systems and for predicting adsorption equilibrium behavior of binary and/or multicomponent gaseous mixtures on active carbon under wide range of conditions, without time consuming and expensive experimental determination.

scholarly journals Application of adsorption potential theory in prediction of CO2 and CH4 adsorption on carbon molecular sieves

2018 ◽  
Vol 36 (9-10) ◽  
pp. 1669-1686
Author(s):  
Xue Song ◽  
Li’ao Wang ◽  
Yifu Li ◽  
Yunmin Zeng ◽  
Xinyuan Zhan ◽  
...  
Keyword(s):  
Potential Theory ◽  
Molecular Sieves ◽  
Gas Adsorption ◽  
Characteristic Curve ◽  
Empirical Method ◽  
Adsorption Potential ◽  
Adsorption Characteristic ◽  
Carbon Molecular Sieves ◽  
Adsorbed Phase ◽  
Adsorption Potential Theory

The adsorption of CO2 and CH4 on carbon molecular sieves was studied based on the adsorption potential theory, which is widely used in gas adsorption on microporous adsorbents. The methods to obtain the adsorption density in the adsorbed phase, including Ozawa’s method and the empirical method, and the methods to calculate the virtual saturation vapor pressure, including Dubinin’s method and Amankwah’s method, were discussed. A functional exponential form proposed in this study could describe the adsorption characteristic curve better than the cubic polynomial and logarithmic function used in the previous literature. A new model, which expresses the correlation of adsorbed amount, temperature, and pressure, was proposed and verified experimentally. The model provides a reliable way to predict the adsorption isotherms of CO2 and CH4 on carbon molecular sieves at different temperatures according to the data measured at a certain temperature and to select a proper kind of carbon molecular sieve in CO2/CH4 separation.

scholarly journals Adsorption of Benzene and Ethanol on Activated Carbon, MCM-41 and Zeolite Y

1998 ◽  
Vol 16 (6) ◽  
pp. 439-452 ◽  
Author(s):  
C. Nguyen ◽  
D.D. Do
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Active Carbon ◽  
Capillary Condensation ◽  
Zeolite Y ◽  
Nitrogen Adsorption ◽  
Relative Pressure ◽  
Wide Range ◽  
Mcm 41

The adsorption of benzene and ethanol at 0, 15 and 30°C on to a number of adsorbents were studied to investigate their performance in the removal of VOCs. The isotherms were measured over a wide range of relative pressure in order to study the contribution of the micropore adsorption and the capillary condensation in mesopores. A model describing the adsorption of subcritical vapours was tested against the isotherm data. It was found that results obtained from the isotherm fitting of benzene and ethanol experimental data were consistent with each other and also with the results of nitrogen adsorption at 77 K. Among the adsorbents studied, Ajax active carbon was found to be the most practical adsorbent for the removal of VOCs.

scholarly journals Detecting cybersecurity attacks across different network features and learners

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Joffrey L. Leevy ◽  
John Hancock ◽  
Richard Zuech ◽  
Taghi M. Khoshgoftaar
Keyword(s):  
Feature Selection ◽  
Intrusion Detection ◽  
Operating Characteristic ◽  
Characteristic Curve ◽  
Machine Learning Algorithms ◽  
Feature Selection Technique ◽  
Impact Performance ◽  
Detection Model ◽  
Wide Range ◽  
Research Questions

AbstractMachine learning algorithms efficiently trained on intrusion detection datasets can detect network traffic capable of jeopardizing an information system. In this study, we use the CSE-CIC-IDS2018 dataset to investigate ensemble feature selection on the performance of seven classifiers. CSE-CIC-IDS2018 is big data (about 16,000,000 instances), publicly available, modern, and covers a wide range of realistic attack types. Our contribution is centered around answers to three research questions. The first question is, “Does feature selection impact performance of classifiers in terms of Area Under the Receiver Operating Characteristic Curve (AUC) and F1-score?” The second question is, “Does including the Destination_Port categorical feature significantly impact performance of LightGBM and Catboost in terms of AUC and F1-score?” The third question is, “Does the choice of classifier: Decision Tree (DT), Random Forest (RF), Naive Bayes (NB), Logistic Regression (LR), Catboost, LightGBM, or XGBoost, significantly impact performance in terms of AUC and F1-score?” These research questions are all answered in the affirmative and provide valuable, practical information for the development of an efficient intrusion detection model. To the best of our knowledge, we are the first to use an ensemble feature selection technique with the CSE-CIC-IDS2018 dataset.

Sorption of phenols on hexadecyltrimethylammonium- modified bentonite: Application of Polanyi−Manes potential theory

2020 ◽  
pp. 0958305X2097728
Author(s):  
Jiyeon Choi ◽  
Dong-Ik Slong ◽  
Won Sik Shin
Keyword(s):  
Molar Volume ◽  
Potential Theory ◽  
Characteristic Curve ◽  
Chemical Compositions ◽  
Pore Filling ◽  
Sorption Data ◽  
Similar Chemical ◽  
Competitive Model ◽  
Sorption Potential ◽  
Sorption Systems

This study investigated the sorption of phenol and 4-chlorophenol (4-CP) on natural bentonite modified with hexadecyltrimethylammonium (HDTMA) cation. The Freundlich, Langmuir, Dubinin−Radushkevich (DR), Sips, and Polanyi−Dubinin−Manes (PDM) models fitted the sorption data well (R2 > 0.92). The Freundlich coefficient and the maximum sorbed amount of the Langmuir and PDM models of 4-CP were higher than phenol because of higher hydrophobicity (log Kow = 2.39 for 4-CP and 1.46 for phenol). The PDM model that includes solubility and molar volume was highly useful in predicting the sorption of phenols having widely different hydrophobicity and solubility. The characteristic curves, the plot of sorbed volume ( qv) versus the sorption potential per molar volume ( ε/ Vm) of 4-CP and phenol were distinctly different although they have similar chemical compositions. The selectivity of 4-CP (3.72) was higher than that of phenol (0.27) in binary sorption systems. The sorbed volume ( qv) in the binary sorption was remarkably reduced and the characteristic curve had wider distribution owing to competition in pore-filling. The sorption behaviors were elucidated by partitioning and pore-filling mechanisms. Among the tested binary sorption models, the modified Langmuir competitive model was the best in the prediction of the binary sorption (R2 > 0.98).

Measurement of Soil Suction and Soil-Water Characteristics of Bentonite-Sand Mixtures

2010 ◽  
Author(s):  
Pan Hu ◽  
Qing Yang ◽  
Maotian Luan
Keyword(s):  
Soil Water ◽  
Vapor Phase ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Phase Method ◽  
Soil Suction ◽  
Compacted Bentonite ◽  
Water Characteristics ◽  
Wide Range ◽  
High Level

The soil-water characteristic curve (SWCC) is a widely used experimental means for assessing fundamental properties of unsaturated soils for a wide range of soil suction values. The study of SWCC is helpful because some properties of unsaturated soils can be predicted from it. Nowadays, much attention has been paid to the behaviours of highly compacted bentonite-sand mixtures used in engineering barriers for high level radioactive nuclear waste disposal. It is very important to study the various performances of bentonite-sand mixtures in order to insure the safety of high-level radioactive waste (HLW) repository. After an introduction to vapor phase method and osmotic technique, a laboratory study has been carried out on compacted bentonite-sand mixtures. The SWCC of bentonite-sand mixtures has been obtained and analyzed. The results show that the vapor phase method and osmotic technique is suitable to the unsaturated soils with high and low suction.

scholarly journals Cocrystals of Ethenzamide With 2-Nitrobenzoic Acid - Conformational Analysis, MD Simulations And DFT Investigations

2021 ◽  
Author(s):  
Y. Sheena Mary ◽  
Y. Shyma Mary ◽  
Razieh Razavi
Keyword(s):  
Hydrogen Bond ◽  
Conformational Analysis ◽  
Crystal Engineering ◽  
Energy Charge ◽  
Thermodynamic Characteristics ◽  
Md Simulations ◽  
Pharmaceutical Chemistry ◽  
Nitrobenzoic Acid ◽  
Wide Range ◽  
Stability Energy

Abstract In crystal engineering and pharmaceutical chemistry, cocrystals have a wide range of applications. Ethenzamide (EA) is found to form cocrystal with 2-nitrobenzoic acid (NBA). Geometry properties like stability energy, charge distribution, bond length, electronic properties and thermodynamic characteristics have been analyzed. The C-H…O hydrogen bond involves C-H of EA and oxygen of NBA. Configuration with the angle, N3-C4-C5-C6 gives the lowest energy conformation. Partition coefficient value suggests that EA-NBA has pharmaceutics behavior. RMSD values show the simulation’s relative stability and the complexes, remained stable throughout.

scholarly journals The Russian Aphasia Test: The first comprehensive, quantitative, standardized, and computerized aphasia language battery in Russian

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258946
Author(s):  
Maria V. Ivanova ◽  
Yulia S. Akinina ◽  
Olga A. Soloukhina ◽  
Ekaterina V. Iskra ◽  
Olga V. Buivolova ◽  
...  
Keyword(s):  
Psychometric Properties ◽  
Characteristic Curve ◽  
High Sensitivity ◽  
Clinical Work ◽  
Assessment Tools ◽  
Assessment Instrument ◽  
Auditory Comprehension ◽  
Specific Level ◽  
Cutoff Values ◽  
Wide Range

The lack of standardized language assessment tools in Russian impedes clinical work, evidence-based practice, and research in Russian-speaking clinical populations. To address this gap in assessment of neurogenic language disorders, we developed and standardized a new comprehensive assessment instrument–the Russian Aphasia Test (RAT). The principal novelty of the RAT is that each subtest corresponds to a specific level of linguistic processing (phonological, lexical-semantic, syntactic, and discourse) in different domains: auditory comprehension, repetition, and oral production. In designing the test, we took into consideration various (psycho)linguistic factors known to influence language performance, as well as specific properties of Russian. The current paper describes the development of the RAT and reports its psychometric properties. A tablet-based version of the RAT was administered to 85 patients with different types and severity of aphasia and to 106 age-matched neurologically healthy controls. We established cutoff values for each subtest indicating deficit in a given task and cutoff values for aphasia based on the Receiver Operating Characteristic curve analysis of the composite score. The RAT showed very high sensitivity (> .93) and specificity (> .96), substantiating its validity for determining presence of aphasia. The test’s high construct validity was evidenced by strong correlations between subtests measuring similar linguistic processes. The concurrent validity of the test was also strong as demonstrated by a high correlation with an existing aphasia battery. Overall high internal, inter-rater, and test-retest reliability were obtained. The RAT is the first comprehensive aphasia language battery in Russian with properly established psychometric properties. It is sensitive to a wide range of language deficits in aphasia and can reliably characterize individual profiles of language impairments. Notably, the RAT is the first comprehensive aphasia test in any language to be fully automatized for administration on a tablet, maximizing further standardization of presentation and scoring procedures.

scholarly journals Equation of state for rhodium at high pressures

2021 ◽  
Vol 2057 (1) ◽  
pp. 012118
Author(s):  
K V Khishchenko
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Equation Of State ◽  
Internal Energy ◽  
Specific Volume ◽  
High Pressures ◽  
Thermodynamic Characteristics ◽  
Wide Range ◽  
Hydrodynamic Processes

Abstract An equation of state has been developed for rhodium in a wide range of changes in the specific volume and internal energy. The results of calculations of the thermodynamic characteristics of this metal are presented in comparison with the available experimental data at high pressures. This equation of state can be used in the numerical simulation of hydrodynamic processes under intense impulse influences on matter.

Thermal equation of state for real gas in a wide range of state parameters, including the critical region

2008 ◽  
Vol 15 (3) ◽  
pp. 359-368 ◽  
Author(s):  
A. B. Kaplun ◽  
B. I. Kidyarov ◽  
A. B. Meshalkin ◽  
A. V. Shishkin
Keyword(s):  
Equation Of State ◽  
Critical Region ◽  
Thermal Equation ◽  
Real Gas ◽  
Thermal Equation Of State ◽  
Wide Range
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