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1
Content available On the prognosis of the growth of a heterostructure from a gas phase to analyze the possibility of decreasing mismatch-induced stresses
Pankratov Evgeny L.
Computer Methods in Materials Science
|
2021
|
Vol. 21, No. 2
105--122
EN
An approach to decreasing mismatch-induced stress in a heterostructure by radiation processing during growth from the gas phase is introduced in this paper. Within the framework of the approach with decreasing mismatch-induced stresses, one can find the acceleration of the recombination and diffusion of radiation defects generated during radiation processing. An analytical approach for analyzing mass and heat transfer is also introduced. The approach provides the opportunity to simultaneously take into account spatial and temporal variations of mass transfer parameters. At the same time, the approach allows the nonlinearity of the considered processes to be taken into account.
2
Content available A model for changing the technological process for the growth of epitaxial layers by means of the heating of the growth zone
Pankratov Evgeny L.
Computer Methods in Materials Science
|
2021
|
Vol. 21, No. 1
5--12
EN
The nonstationary transfer of heat during epitaxial layer growth in gas phase epitaxy reactors is analyzed within the work. Based on this analysis, several recommendations on the organization of the heating of the growth zone to increase the homogeneity of the epitaxial layers were formulated. An approach to analyze the transfer of heat during epitaxial layer growth from the gas phase is also introduced. The approach leads to the possibility of simultaneously accounting for heat transfer nonlinearity and changes of parameters of heat transfer in both space and time.
3
Content available remote Zastosowanie ziarnistych węgli aktywnych do usuwania chloru z gazów odlotowych
Żarczyński Andrzej, Śmiechowska Marlena, Rylski Adam, Zaborowski Marcin, Kaźmierczak Marek, Szynkowska Małgorzata I.
Przemysł Chemiczny
|
2020
|
T. 99, nr 8
1251--1253
PL
Zbadano 4 handlowe gatunki węgli aktywnych w zakresie skuteczności usuwania chloru ze spalin. Określono ich parametry fizykochemiczne, takie jak zawartość popiołu i wilgoci, liczba jodowa, powierzchnia właściwa, porowatość i wielkość porów. Badane węgle skutecznie pochłaniały chlor ze spalin i mogą być przydatne do zabezpieczania elektrochemicznych czujników gazów. Szczególnie obiecujące wyniki uzyskano w przypadku węgla z łupin orzecha kokosowego w usuwaniu chloru ze spalin suchych oraz węgla do chromatografii w oczyszczaniu spalin wilgotnych.
EN
Cl₂ was adsorbed from waste gases (140 mg/m3) on 4 com. activated C at 20°C for 16.3–49.4 h. Their phys.-chem. and structural properties were detd. The most efficient Cl₂ removal from dry flue gases was achieved on the activated C produced from coconut shells and from wet flue gases was achieved on activated C used in chromatog.
4
Content available Justification of the rheological model of process of plastic material injection by the rollers
Szwedziak Katarzyna, Stadnyk Igor, Golyachuk Sergey, Grzywacz Żaneta
Agricultural Engineering
|
2019
|
Vol. 23, No. 3
101--114
EN
It is justified thatproblems related to the changes in structural and mechanical properties of plastic material and influence of structural elements of equipment and modes of implementation of the for-mation process on them are considered detail, taking into account empirical data, theoretical dependencies and results of physical experiments. It was established that during the mechanical influence of rollers with grooves on a structured dispersion plastic material in the node of injection of the molding machine, internal shear, and shearing deformation have a preponderant value. Accordingly, the productivity of machines is determined mainly by the structural parameters of the working bodies geometry, kinematics, and contact area. It is shown that increasing the pressure in the plastic material causes a decrease in its volume, but the relationship between pressure and volume has a nonlinear character. It has been established that regardless the variety of flour from which the plastic material was prepared for bagels, its moisture content and the duration of fermentation reduced viscosity of the effective plastic material along with the increase of the shear stress. The paper describes the refined rheological model of the Bingham body deformation, which develops instantaneously, and the velocity of the common elastic deformation in the dough is a simultaneous function of stresses and temperatures, which are close to exponential ones.
PL
Jest uzasadnione, że problemy zmiany właściwości konstrukcyjnych i mechanicznych materiału plastycznego oraz wpływu na nie elementów konstrukcyjnych sprzętu i sposobów realizacji procesu formowania są rozpatrywane w kompleksowo, biorąc pod uwagę dane empiryczne, zależności teoretyczne i wyniki ek-sperymentów fizycznych. Ustalono, że podczas mechanicznego wpływu rolek z rowkami na ustrukturyzowany materiał dyspersyjny plastyczny w węźle wtrysku maszyny do formowania, ścinanie wewnętrzne i odkształcenie ścinające mają przewagę. W związku z tym wydajność maszyn zależy głównie od parametrów kon-strukcyjnych geometrii ciał roboczych, kinematyki i powierzchni styku. Pokazano, że zwiększenie ciśnienia w materiale plastycznym powoduje zmniejszenie jego objętości, ale związek między ciśnieniem i objętością ma charakter nieliniowy. Ustalono, że bez względu na różnorodność mąki, z której przygotowano materiał plastyczny na bułec-zki, jego wilgotność i czas trwania fermentacji zmniejsza lepkość efektywnego tworzywa sztucznego wraz ze wzrostem naprężeń ścinających W artykule opisano wyrafinowany model reologiczny deformacji ciała Binghama, która rozwija się natychmiast, a prędkość wspólnej deformacji sprężystej w cieście jest jednoczesną funkcją naprężeń i temperatur, które są bliskie wykładniczym.
5
Content available remote Percolation Transitions and Fluid State Boundaries
Woodcock L. W.
Computational Methods in Science and Technology
|
2017
|
Vol. 23, No. 3
281--294
EN
Percolation transitions define gas- and liquid-state limits of existence. For simple model fluids percolation phenomena vary fundamentally with dimensionality (d). In 3d the accessible volume (VA) and excluded volume (VE = V --VA) percolation transitions occur at different densities, whereas in 2d they coincide. The region of overlap for 3d fluids can be identified as the origin of a supercritical mesophase. This difference between 2d and 3d systems vitiates the hypothetical concept of “universality” in the description of critical phenomena. Thermodynamic states at which VA and VE, for a spherical molecule diameter , percolates the whole volume of an ideal gas, together with MD computations of percolation loci for the penetrable cohesive sphere (PCS) model of gas-liquid equilibria, show a connection between the intersection of percolation loci, and the 1st-order phase-separation transition. The results accord with previous findings for square-well and Lennard-Jones model critical and supercritical fluid equilibria. Percolation loci for real liquids, e.g. CO2 and argon, can be determined from literature thermodynamic equation-of-state data, and exhibit similar supercritical gas- and liquid-state bounds. For these real fluids the mesophase bounds extend to low density and pressures and appear to converge onto the Boyle temperature (TB) in the low-density limit.
6
Review of models for thermal treatment of waste in a rotary kiln
Wajda A., Jaworski T.
Archivum Combustionis
|
2017
|
Vol. 37 nr 2
119--126
EN
Rotary kiln is a device used on a large scale in the industry, including thermal waste treatment. Mathematical modeling of a rotary kiln consists most often of the development of several submodels occurring in the process phases, usually solid and gas, and linking them together. Most of the existing mathematical models describe the work of a rotary kiln co-incinerating waste, e.g. cement kilns, there is a lack of targeted, comprehensive models of the waste combustion process in structures only designed for this purpose, and therefore integrated with the vertical post-combustion chamber. The work presents a tabular list of models according to specific criteria that result of the method of dividing the process model into smaller elements. The conclusion from the analysis is the existence of many factors that require development in the form of a rotary kiln for the thermal treatment of waste.
7
Content available remote Wpływ składu fazy gazowej na właściwości katalizatora wanadowego stosowanego przy produkcji kwasu siarkowego
Grzesiak P., Grobela M., Motała R., Łukaszyk J.
Przemysł Chemiczny
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2011
|
T. 90, nr 12
2193-2197
8
The Nature of Hydrogen Bonding in Selected Hydrazide Derivatives Investigated via Static Models and Car-Parrinello Molecular Dynamics
Jezierska A., Novič M., Panek J. J.
Polish Journal of Chemistry
|
2009
|
Vol. 83, nr 5
799-819
EN
The geometric and spectrocopic properties of 2-hydroxy-thiobenzhydrazide and 2-hydroxy-benzhydrazide were investigated within the frame work of Density Functional Theory (DFT). Special attention was devoted to the description and analysis of intra- and intermolecular hydrogen bonds. The choice of the compounds was dictated by their structural similarity and the presence of two types of hydrogen bridges: O–H...S (in 2-hydroxy-thiobenzhydrazide, less common) and O–H...O (in 2-hydroxy-benzhydrazide). The latter could be classified as a low-barrier hydrogen bond (LBHB). First the DFT method was used to obtain the geometric parameters for the monomeric and dimeric forms of the compounds at various levels of theory. Then the binding energy was calculated for the dimeric forms to estimate the strength of the intermolecular hydrogen bonds. Atoms in Molecules (AIM) theory was applied to show quantitatively how the formation of the intermolecular hydrogen bonds affects the strength of the intramolecular hydrogen bonds. The electron density and its Laplacian were calculated for the bond critical points defining the H-bridges. Car-Parrinello molecular dynamics (CPMD) was then used to investigate the changes in the geometric parameters as a function of simulation time. This part of the computational study was performed in vacuo and in the solid state. The vibrational properties of the investigated hydrazides were obtained via Fourier transform of the autocorrelation functions of the dipole moment and atomic velocity. It was found that the formation of the intermolecular H-bonds does not significantly affect the strength of the intramolecular H-bonds. There fore inductive and steric effects out side the immediate vicinity of the intramolecular bridge have minor influence on its investigated properties. The application of CPMD gave a more detailed picture of the bridged protons’ dynamics. The computational results agree with available experimental data. The influence of the intermolecular hydrogen bonding net work and non-bonded crystal field interactions on the vibrational features of the investigated molecules is demonstrated and discussed.
9
Change of Prototropic Equilibria for Uracil when Going from Neutral Molecule to Charged Radicals. Quantum-Chemical Studies in the Gas Phase
Raczyńska E. D., Zientara K., Kolczyńska K., Stępniewski T. M.
Polish Journal of Chemistry
|
2009
|
Vol. 83, nr 5
821-834
EN
To understand various substitution, oxidation or degradation reactions for uracil, quantum-chem i calcalculations were performed for two classes of charged radicals (cations and anions) of uracil (U+ź and U-ź) and model compounds: phenol (P+ź and P-ź) and hydroxyazines (HP1-4+ź and HP1+-4-ź). In calculations, all possible eighteen prototropic tautomers-rotamers of U and all possible five prototropic tautomers-rotamers of P and HP1-4 were considered. Stabilities, internal effects and aromatic character, estimated for charged radicals, were compared with those observed previously for neutral molecules. The great est changes of the tautomeric preferences take place for radical anions. One-electron reduction stabilizes the keto and amide functions in studied compounds, whereas one-electron oxidation favors the enol function for ph nol and the amide function for uracil and hydroxyazines.
10
Modelowanie spalania fazy gazowej w komorach paleniskowych kotłów energetycznych
Modliński N.
Systems : journal of transdisciplinary systems science
|
2008
|
Vol. 13, spec. iss. 2/2
46--52
EN
The paper investigates influence of homogenous phase reaction mechanism on results of simulations of tangentially fired pulverised coal combustion chamber equipped with low-emission RI-JET2 burners. Global mechanisms of Hautmann[2], Jones and Lindstedt [3] were investigated. Mechanisms have been implemented into two turbulent gas phase combustion models: - Eddy Break-Up and Eddy Dissipation Concept. CO level in the chamber was examined. The results indicate large influence of combustion model choice on the CO level. In case of boiler with rapid ignition burners EDC model is probably more accurate than EBU - very popular in boilers with jest burners. Results of the global mechanisms investigation suggest a necessity to implement reduced mechanisms into combustion model.
11
1H and 13C Nuclear Magnetic Shielding in Gaseous and Liquid Propene
Kubiszewski M., Makulski W.
Polish Journal of Chemistry
|
2008
|
Vol. 82, nr 7
1457-1457
EN
Propylene, C3H6, was studied by high resolution NMR spectroscopy in liquid and gaseous state at 300 K. Extrapolation of gas-phase 1H and 13C chemical shifts to the ero-den sity limit permit ted the determinations of absolute nuclear magnetic shielding in the isolated propylene molecule. These new experimental results were used in a reliable verification of ab in itio calculations of proton and carbon nuclear magnetic shielding. The analogous pure liquid propylene spectra were also measured. The second virial coefficients and gas-to-liquid shifts were discussed in the context of intermolecular inter actions in gas and association in liquid phase.
12
Content available remote Opis fazy gazowej w pirolizie biomasy za pomocą równowagi termodynamicznej
Warowny W., Celińska A.
Gaz, Woda i Technika Sanitarna
|
2008
|
Nr 7-8
9-13
EN
The purpose of this paper was to evaluate thermodynamic equilibrium characteristics of gaseous phase after pyrolysis of birch and palm. Results of calculations provide clearer insight into several parameters on the gas produced by pyrolysis of studied biomasses.
13
Content available remote Zastosowanie równań stanu do opisu fazy gazowej i równowag fazowych
Warowny W., Sarnecki D.
Gaz, Woda i Technika Sanitarna
|
2007
|
Nr 10
9-13
EN
The role of equations of state in describing gas phase and liquid: steam phase equilibrium in perfect gas and in real gas. Conditions for applying a few selected equations of state. Examples of using equations of state in gas industry, with natural gas.
14
Content available remote Wielkości termodynamiczne do opisu zachowania się fazy gazowej
Warowny W.
Gaz, Woda i Technika Sanitarna
|
2007
|
Nr 11
5-11
EN
Various thermodynamic expressions are necessary (including: residual and departure thermodynamic functions, fuga-city, Joule-Thomson coefficient, isentropic exponent, velocity of sound, and so on) for description of the physical processes in the gas phase, under pressure. Predicting of the gas phase behavior is important in the gas industry, so the majority of volumetric calculations carried out are based on the compressibility factor and equations of state.
15
Nuclear Magnetic Shielding and Indirect Spin-Spin Coupling Constants in Cyclopropane. Gaseous and Liquid NMR Measurements
Makulski W., Wilczek M.
Polish Journal of Chemistry
|
2006
|
Vol. 80, nr 7
1055-1060
EN
Cyclopropane (CH2)3 was studied by advanced methods of NMR spectroscopy in liquid and gaseous states at 300 K. Extrapolation of gas-phase chemical shifts to the zero-density limit allowed the determinations of 1H and 13C absolute nuclear magnetic shieldings of an isolated cyclopropane molecule. The indirect spin-spin coupling constants were extracted from experimental spectra and compared with the calculated values reported in the literature.
16
Content available remote Faza gazowa w szkle. Cz. II.
Kuśnierz A.
Szkło i Ceramika
|
2004
|
R. 55, nr 6
26-27
PL
Badano rozpuszczalność gazów w szkłach. Próbki o różnym składzie chemicznym i różnej zawartości środków klarujących analizowano przy użyciu metody chromatografii gazowej. Przedstawiono rezultaty wstępnych pomiarów dla wybranych próbek szkieł topionych w temperaturze 1450 stopni C oraz czasie topienia 4 godzin. Różna ilość wyekstrahowanych składników gazowych w porównaniu ze szkłem bazowym wskazuje, że efektywność zastosowanych środków klarujących jest zróżnicowana. Najsilniejszy efekt klarujący uzyskuje się stosując mieszankę As2O3. Sb2O3, NaNO w proporcjach 1 : 1 : 1.
EN
The solubility of gases in glass was investigated. The samples of glasses of different chemical composition and with content of different fining agents were melted and examined by using gas chromatography method. The results of the initial measurements for selected samples of glasses melted at a temperature of 1450 degrees C for 4 hours. The varied amounts of gasseous components extracted, in relation to the reference glass, indicates that the fining effectivity of the refining agents had been applied was strongly differentiated. The strongest refining effect was obtained with a mixture of As2O3. Sb2O3, NaNO in a rate 1 : 1 : 1.
17
Content available remote Faza gazowa w szkle. Cz.I.
Kuśnierz A.
Szkło i Ceramika
|
2003
|
R. 54, nr 6
12-15
PL
W artykule przedstawiono w skrócie wybrane zagadnienia dotyczące wydzielania się gazów w procesie stapiania zestawu surowcowego, oddziaływanie wydzielonych gazów z masą szklaną i czynników wpływających na proces klarowania masy szklanej. Przebieg tych procesów ma istotny wpływ na zawartość gazów w gotowym wyrobie szklanym.
EN
This article presents, in a short cut, selected questions concerning emanating gases in the process of melting the batch, as well as the influence of the gases on melting glass and factors influencing the process of refining the melt glass. The course of these processes is significant for the content of gas in a ready product glass.
18
Content available remote Porównawcze studium nad efektem rozcieńczania fazy stałej i gazowej w procesie utleniającego sprzęgania metanu
Skutil K., Tórz A., Taniewski M.
Przemysł Chemiczny
|
2003
|
T. 82, nr 8-9
634-636
19
Współczynnik dyfuzji w fazie gazowej : porównanie wybranych korelacji
Thullie J., Bodzek M.
Inżynieria i Aparatura Chemiczna
|
2003
|
Nr 4
12-15
PL
W pracy przedstawiono porównanie różnych korelacji dla określania wartości binarnych współczynników dyfuzji w gazach. Stwierdzono, że zalecany powszechnie wzór Fullera nie zawsze przewiduje właściwe wartości. Przedstawione wyniki sugerują stosowanie korelacji Hirschfeldera bądź Slattery'ego.
EN
A comparison of different correlations for calculation binary diffusion coefficient in gases is shown. It has been stated that the widely used Fuller equations do not predict correct values. Therefore, based on the results presented, one suggests the use of the Hirschfelder or Slattery correlations.
20
Problemy dezodoryzacji metodą ozonowania w fazie gazowej
Tatoj P.
Inżynieria i Aparatura Chemiczna
|
2002
|
Nr 1
20-21
PL
Omówiono rezultaty badań dezodoryzacji metodą ozonowania w fazie gazowej wybranych odorantów: olejków lawendowego, goździkowego i różanego oraz trietyloaminy, alkoholu etylowego i izoamylowego, octanu etylu i toluenu. Wykazano, że wysoka skuteczność procesu wymaga dużych nadmiarów ozonu i długich czasów kontaktu oraz, że w produktach reakcji pojawiają się nowe związki chemiczne, których jednak nie identyfikowano. Uzyskane wyniki wskazują, że dezodoryzację metodą ozonowania w fazie gazowej można stosować tylko w specyficznych warunkach, po przeprowadzeniu dokładnych badań wstępnych określających parametry procesu i przy pełnej identyfikacji powstających produktów reakcji. Jednak nawet w takich przypadkach należy się liczyć z problemami natury technicznej i ekonomicznej. Z przesłanek tych wynika, że dez-odoryzacja metodą ozonowania w fazie gazowej nadaje się do aplikacji tylko w specyficznych warunkach, kiedy inne metody zawodzą.
EN
The experimental results dealing with deodorization using the ozonization method in gas phase for selected odorants such as: lavender, clove and rose oils, triethylamine, ethanol, isoamyl alcohol, ethyl acetate and toluene have been discussed. It has been proved that a high process efficiency required large ozone overdoses and long contact time and new substances appeased in reaction products. However, these substances have not been identified. The results indicate that the ozonization in gas phase can be used only in the specific conditions, after precise initial tests determining process parameters and reaction products. Even for these cases, some technical and economical issues can be encountered. In the light of circumstances presented, one can stated that deodorization using the ozonization method in gas phase is applicable only in specific conditions, when other methods are inappropriate.
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