scholarly journals High-Accuracy PVT Relationships for Compressed Fluids and Their Application to BET-like Modelling of CO2 and CH4 Adsorption

2007 ◽  
Vol 25 (8) ◽  
pp. 543-559 ◽  
Author(s):  
Janina Milewska-Duda ◽  
Jan Tadeusz Duda
Keyword(s):  
State Equation ◽  
High Accuracy ◽  
Theoretical Description ◽  
Theoretical Modelling ◽  
Hard Sphere Model ◽  
Cohesion Energy ◽  
Critical Temperatures ◽  
Compression Factor ◽  
Energy Relationships ◽  
Factor Data

This paper presents a set of high-accuracy formulae enabling the evaluation of the compression factor, activity and cohesion energy of fluids at near-critical and super-critical temperatures, with reduced molar volumes ranging from 0.4. Such data are necessary in BET-like theoretical modelling of adsorption process. The proposed fluid state equation (PVT relationship) combines a theoretical description of the fluid entropy (based on a hard-sphere model) with cohesion energy relationships obtained via high-accuracy approximations of universal compression factor data and vapour-liquid equilibria. The resultant relationships are incorporated into a BET-like description of adsorption in materials of irregular microporous structure (LBET model). The set of formulae gathered together in this paper allows the possible effective calculation of adsorption isotherms at near- and super-critical temperatures relative to the pore structures. A multi-variant fitting of the LBET model to the empirical data is proposed to detect active constraints for multilayer adsorption and, hence, to obtain information on the structure of the pores. Application of the formulae to the analysis of methane and carbon dioxide adsorption onto an active carbon is discussed.

scholarly journals An Inverse Problem Involving a Viscous Eikonal Equation with Applications in Electrophysiology

2021 ◽  
Author(s):  
Karl Kunisch ◽  
Philip Trautmann
Keyword(s):  
Inverse Problem ◽  
Least Squares ◽  
Eikonal Equation ◽  
State Equation ◽  
High Accuracy ◽  
Well Posedness ◽  
Numerical Examples ◽  
Marquardt Method ◽  
Math Biol ◽  
Levenberg Marquardt

AbstractIn this work we discuss the reconstruction of cardiac activation instants based on a viscous Eikonal equation from boundary observations. The problem is formulated as a least squares problem and solved by a projected version of the Levenberg–Marquardt method. Moreover, we analyze the well-posedness of the state equation and derive the gradient of the least squares functional with respect to the activation instants. In the numerical examples we also conduct an experiment in which the location of the activation sites and the activation instants are reconstructed jointly based on an adapted version of the shape gradient method from (J. Math. Biol. 79, 2033–2068, 2019). We are able to reconstruct the activation instants as well as the locations of the activations with high accuracy relative to the noise level.

Thermodynamic of the charged AdS black holes in Rastall gravity: P − V critical and Joule–Thomson expansion

2020 ◽  
Vol 35 (14) ◽  
pp. 2050113
Author(s):  
Sen Guo ◽  
Yan Han ◽  
Guo Ping Li
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Critical Temperature ◽  
Critical Exponents ◽  
State Equation ◽  
The State ◽  
Thermodynamic Quantities ◽  
Critical Temperatures ◽  
Ads Black Holes ◽  
And Inversion

In this paper, we study the thermodynamic of the charged AdS black holes in Rastall gravity. Firstly, the thermodynamic quantities of the charged AdS black holes in Rastall gravity are reviewed and the state equation of this black hole is obtained. Then, we investigate the [Formula: see text] critical and the Joule–Thomson expansion of the charged AdS black holes in Rastall gravity in which the critical temperature and the critical exponents are obtained. In addition, we get the inversion temperature and plot the isenthalpic and inversion curves in the [Formula: see text] plane, and also determine the cooling-heating regions of this black hole through the Joule–Thomson expansion. Finally, we investigate the ratio between the minimum inversion and critical temperatures, and find that the Rastall constant [Formula: see text] does not affect of this ratio.

scholarly journals Neutron scattering cross section of diamond nanoparticles

2019 ◽  
Vol 219 ◽  
pp. 10005
Author(s):  
Kenji Mishima ◽  
Toshiya Otomo ◽  
Kazutaka Ikeda ◽  
Hidetoshi Ohshita
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Coherent Scattering ◽  
Theoretical Description ◽  
Powder Sample ◽  
Scattering Cross Section ◽  
Hard Sphere Model ◽  
Particle Structure ◽  
Diamond Nanoparticles ◽  
Scattering Cross

Due to their large coherent scattering cross section, diamond nanoparticles (DNPs) are considered as a promising candidate material for a new neutron reflector. For investigation of scattering cross sections of packed samples, we have developed a technique for mechanical compression of DNP powder. Application of 220 MPa allowed us to increase the bulk density from 0.40 g/cm3 to 1.1 g/cm3. The differential cross sections of uncompressed and packed samples were measured using the high-intensity total diffractometer instrument NOVA at J-PARC, covering transfer wavenumbers (q) from 0.6 to 100 nm−1. The q dependence for the compressed sample agreed with the theoretical expectation derived from the Born approximation applied to homogeneous spheres with inclusion of a hard-sphere model to account for the inter-particle structure, whereas the results obtained from the powder sample disagreed. This implies that the theoretical description does not well represent the mesoscopic structure of the DNP powder sample.

Research on a Digital Close-Range Photogrammetric Bridge Deflection Measurement System

2013 ◽  
Vol 392 ◽  
pp. 734-737
Author(s):  
Wan Ting Wang ◽  
Han Bing Liu
Keyword(s):  
Program Development ◽  
Measurement System ◽  
Measurement Method ◽  
Field Tests ◽  
High Accuracy ◽  
Theoretical Description ◽  
System Configuration ◽  
Deflection Measurement ◽  
Analysis Process ◽  
Close Range

This paper introduces a new close-range photogrammetric bridge deflection non-contact measurement method that has high accuracy and efficiency, and can be conveniently used by engineers without help from professional surveyors. After a general theoretical description (analysis process and program development) of a photogrammetric bridge deflection measurement method, the system configuration is introduced and the application is verified through the laboratory and field tests.

scholarly journals MODELAGEM DO COMPORTAMENTO LÍQUIDO-VAPOR EM EQUILÍBRIO ISOBÁRICO PARA A MISTURA HEXAMETILDISILOXANO + ACETATO DE SEC-BUTILA

e-xacta ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 21
Author(s):  
Plínio Ribeiro Rodrigues ◽  
Jéssica Magalhães Neves Nunes
Keyword(s):  
Experimental Data ◽  
Binary System ◽  
Butyl Acetate ◽  
System Modeling ◽  
Equilibrium Composition ◽  
Thermodynamic System ◽  
State Equation ◽  
High Accuracy ◽  
Actual Behavior ◽  
Average Accuracy

O hexametildisiloxano (HMDSO) e o acetato de sec-butila (ACSB) são compostos orgânicos utilizados em diversas aplicações tecnológicas, dentre elas a síntese química de vários produtos de interesse farmacêutico. No presente trabalho, as composições da mistura dos compostos em equilíbrio foram determinadas por meio do método Bolha P, calculado pela equação de estado cúbica com parâmetros de Peng-Robinson para a pressão de 101,3 kPa. Os erros médios percentuais entre os dados calculados e os valores experimentais também foram determinados, o que permitiu mostrar a precisão do modelo estudado em simular o sistema termodinâmico. Dessa maneira, o modelo mostrou-se útil para o cálculo da composição do equilíbrio do sistema binário avaliado, refletindo o comportamento real da mistura com precisão média de 90,57%, sendo, portanto, adequado a aplicações tecnológicas que exijam exatidão relativamente elevada e servindo de base para estudos futuros de modelagem do sistema HMDSO + ACSB. AbstractHexamethyldisiloxane (HMDSO) and sec-butyl acetate (ACSB) are organic compounds used in various technological applications, such as the chemical synthesis of various products of pharmaceutical interest. In the present work, mixture compositions of the compounds in equilibrium were determined by the Bubble P method, calculated by the cubic state equation with Peng-Robinson parameters for the pressure of 101.3 kPa. Mean percentage errors between the calculated and the experimental data were also determined, which allowed to indicate the precision of the model studied for the thermodynamic system modeling. In this way, the model proved to be useful for calculating the equilibrium composition of the evaluated binary system, reflecting the actual behavior of the mixture with an average accuracy of 90.57%; and is therefore suitable for technological applications that require relatively high accuracy and serving as basis for HMDSO + ACSB system future modeling studies.

scholarly journals FABRICATING EXPERIMENTAL EQUIPMENT FOR TESTING GAS LAWS FOR TEACHING AND LEARNING "IDEAL GAS" - GRADE 12 PHYSICS, NATIONAL HIGH SCHOOL PROGRAM 2018

2021 ◽  
Vol 11 (1) ◽  
pp. 72-78
Author(s):  
Viet Hai Phung ◽  
Van Nguyen
Keyword(s):  
High School ◽  
Teaching And Learning ◽  
State Equation ◽  
High Accuracy ◽  
Ideal Gas ◽  
Experimental Equipment ◽  
School Program ◽  
Gas Laws ◽  
Ideal Gases ◽  
High School Program

In this study, we fabricated the experimental equipment for testing gas laws, using eco-friendly and easy-to-find materials. The equipment was able to test, with relatively high accuracy (error less than 1%), the gas laws and demonstrate the state equation of ideal gases. The findings reveal that the equipment and similar experiments can be adopted for teachers’ modeling activities as well as students’ experiments, or teachers can guide their students to fabricate their own equipment as a STEM experience while teaching the topic “Ideal Gas” – Grade 12 Physics, the national high school program 2018.

Recent Progress in Equilibrium Acidity Studies of Organocatalysts

Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 1940-1949 ◽  
Author(s):  
Zhen Li ◽  
Xin Li ◽  
Jin-Pei Cheng
Keyword(s):  
Hydrogen Bonding ◽  
High Accuracy ◽  
Heterocyclic Carbenes ◽  
Cinchona Alkaloids ◽  
Acid Catalysts ◽  
Hydrogen Bond Donor ◽  
Indicator Method ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Double Hydrogen

This account summarizes our recent work on the pK a scales of some frequently used organocatalysts, especially those of hydrogen-bond-donor catalysts and stronger Brønsted acid catalysts. Most of these pK a values were obtained by the Bordwell overlapping indicator method, which is known to provide high accuracy. Linear free-energy relationships associated with pK a values are discussed in relation to understanding of reaction mechanisms.1 Introduction2 Single Hydrogen-Bonding Donors2.1 Proline-Type Organocatalysts2.2 Cinchona Alkaloids Bearing a Hydrogen-Bonding Donor in the 6′-Position3 Double-Hydrogen-Bonding Donors3.1 Thioureas3.2 Squaramides3.3 BINOLs4 Stronger Brønsted Acids5 N-Heterocyclic Carbenes6 Summary and Outlook

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

A New 1,000 kV Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 260-261
Author(s):  
M. Nishigaki ◽  
S. Katagiri ◽  
H. Kimura ◽  
B. Tadano
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Basic Research ◽  
Chromatic Aberration ◽  
High Accuracy ◽  
Biological Specimen ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron

The high voltage electron microscope has many advantageous features in comparison with the ordinary electron microscope. They are a higher penetrating efficiency of the electron, low chromatic aberration, high accuracy of the selected area diffraction and so on. Thus, the high voltage electron microscope becomes an indispensable instrument for the metallurgical, polymer and biological specimen studies. The application of the instrument involves today not only basic research but routine survey in the various fields. Particularly for the latter purpose, the performance, maintenance and reliability of the microscope should be same as those of commercial ones. The authors completed a 500 kV electron microscope in 1964 and a 1,000 kV one in 1966 taking these points into consideration. The construction of our 1,000 kV electron microscope is described below.

Rapid Critical Point Drying of Tissues in a Parr Bomb

1972 ◽  
Vol 30 ◽  
pp. 400-401
Author(s):  
C.A. Baechler ◽  
W. C. Pitchford ◽  
J. M. Riddle ◽  
C.B. Boyd ◽  
H. Kanagawa ◽  
...  
Keyword(s):  
Critical Point ◽  
Critical Pressure ◽  
Soft Tissues ◽  
Biological Tissues ◽  
Critical Temperatures ◽  
Air Drying ◽  
The Past ◽  
Critical Point Drying ◽  
Great Stress ◽  
Infiltration Techniques

Preservation of the topographic ultrastructure of soft biological tissues for examination by scanning electron microscopy has been accomplished in the past by using lengthy epoxy infiltration techniques, or dehydration in ethanol or acetone followed by air drying. Since the former technique requires several days of preparation and the latter technique subjects the tissues to great stress during the phase change encountered during air-drying, an alternate rapid, economical, and reliable method of surface structure preservation was developed. Turnbill and Philpott had used a fluorocarbon for the critical point drying of soft tissues and indicated the advantages of working with fluids having both moderately low critical pressures as well as low critical temperatures. Freon-116 (duPont) which has a critical temperature of 19. 7 C and a critical pressure of 432 psi was used in this study.

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