scholarly journals Assessment of the possibility of the methane to methanol transformation

2008 ◽  
Vol 10 (2) ◽  
pp. 20-26 ◽  
Author(s):  
Beata Michalkiewicz
Keyword(s):  
Sulfuric Acid ◽  
Synthesis Gas ◽  
Methanol Conversion ◽  
Ester Hydrolysis ◽  
Mass Balances ◽  
Preliminary Assessment ◽  
Practical Applications ◽  
Other Substances ◽  
Laboratory Investigations ◽  
The Way

Assessment of the possibility of the methane to methanol transformation The methane to methanol conversion via esterification is an interesting method which makes it possible to eliminate the otherwise necessary phase of obtaining synthesis gas. On the basis of laboratory investigations mass balances for this process were determined. Preliminary assessment of the way of conducting the process and possibilities of practical applications of this technology was also made. It was pointed out that regardless of any possible modifications of methane to methanol conversion via esterification redundant sulfuric acid will always be produced during ester hydrolysis. Production of methanol from methane using this method can only be done when it is combined with producing other substances, which needs using H2SO4.

scholarly journals Assessment of Linearization Approaches for Multibody Dynamics Formulations

2017 ◽  
Vol 12 (4) ◽  
Author(s):  
Francisco González ◽  
Pierangelo Masarati ◽  
Javier Cuadrado ◽  
Miguel A. Naya
Keyword(s):  
Mechanical System ◽  
Multibody Dynamics ◽  
Equations Of Motion ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Practical Applications ◽  
Linearization Methods ◽  
Highly Nonlinear ◽  
Wide Range ◽  
The Way

Formulating the dynamics equations of a mechanical system following a multibody dynamics approach often leads to a set of highly nonlinear differential-algebraic equations (DAEs). While this form of the equations of motion is suitable for a wide range of practical applications, in some cases it is necessary to have access to the linearized system dynamics. This is the case when stability and modal analyses are to be carried out; the definition of plant and system models for certain control algorithms and state estimators also requires a linear expression of the dynamics. A number of methods for the linearization of multibody dynamics can be found in the literature. They differ in both the approach that they follow to handle the equations of motion and the way in which they deliver their results, which in turn are determined by the selection of the generalized coordinates used to describe the mechanical system. This selection is closely related to the way in which the kinematic constraints of the system are treated. Three major approaches can be distinguished and used to categorize most of the linearization methods published so far. In this work, we demonstrate the properties of each approach in the linearization of systems in static equilibrium, illustrating them with the study of two representative examples.

Debating points of accounting to reflect escrow account transactions by the developer organization

2021 ◽  
Vol 22 (4) ◽  
pp. 438-458
Author(s):  
Margarita F. SAFONOVA ◽  
Yuliya V. MARCHENKO
Keyword(s):  
Analytical Methods ◽  
Balance Sheet ◽  
Theory And Practice ◽  
Housing Construction ◽  
Project Financing ◽  
Practical Applications ◽  
Construction Companies ◽  
Business Entities ◽  
The Way

Subject. This article discusses the issues of reflection of information on settlements with equity construction investors both on off-balance and balance sheet accounts of the developer. Objectives. The article aims to determine the extent of the transition to project financing of housing construction using escrow accounts, explore options for accounting for incoming funds of equity construction investors, and develop a methodology that helps avoid tampering with the balance sheet total of developers. Methods. For the study, we used induction, deduction, analysis, synthesis, and the calculation and graphic, monographic, and accounting and analytical methods. Results. In some cases, the findings have revealed significant discrepancies the way funds available to escrow accounts get accounted for. An analysis of the causes of these deviations confirms the need to develop an off-balance sheet accounting methodology. Conclusions and Relevance. The updated methodology is structured in such a way that the investors' funds are accounted by the developer in one account, another account is used for settlements with the equity construction investors, and the funds placed by the bank on the escrow accounts are reflected in the off-balance sheet of the developer, without misrepresenting the balance sheet total. The results can be used in the theory and practice of construction companies in the process of accounting and reporting by business entities of various forms of ownership, as well as for further scientific developments and practical applications.

A comparison of the mechanisms of hydrolysis of benzimidates, esters, and amides in sulfuric acid media

2005 ◽  
Vol 83 (9) ◽  
pp. 1391-1399 ◽  
Author(s):  
Robin A Cox
Keyword(s):  
Sulfuric Acid ◽  
Isotope Effects ◽  
Ester Hydrolysis ◽  
Water Molecules ◽  
Acid Media ◽  
Tetrahedral Intermediate ◽  
Amide Hydrolysis ◽  
Solvent Isotope ◽  
Reaction Media ◽  
Hydrolysis Of

The mechanisms given in textbooks for both ester and amide hydrolysis in acid media are in need of revision. To illustrate this, benzimidates were chosen as model compounds for oxygen protonated benzamides. In aqueous sulfuric acid media they hydrolyze either by a mechanism involving attack of two water molecules at the carbonyl carbon to give a neutral tetrahedral intermediate directly, as in ester hydrolysis, or by an SN2 attack of two water molecules at the alkyl group of the alkoxy oxygen to form the corresponding amide, or by both mechanisms, depending on the structure of the benzimidate. The major line of evidence leading to these conclusions is the behavior of the excess acidity plots resulting from the rate constants obtained for the hydrolyses as functions of acid concentration and temperature. The first of these mechanisms is in fact very similar to one found for the hydrolysis of benzamides, as inferred from: (1) similar excess acidity plot behaviour; and (2) the observed solvent isotope effects for amide hydrolysis, which are fully consistent with the involvement of two water molecules, but not with one or with three (or more). This mechanism starts out as essentially the same one as that found for ester hydrolysis under the same conditions. Differences arise because the neutral tetrahedral intermediate, formed directly as a result of the protonated substrate being attacked by two water molecules (not one), possesses an easily protonated nitrogen in the amide and benzimidate cases, explaining both the lack of 18O exchange observed for amide hydrolysis and the irreversibility of the reaction. Protonated tetrahedral intermediates are too unstable to exist in the reaction media; in fact, protonation of an sp3 hybridized oxygen to put a full positive charge on it is extremely difficult. (This means that individual protonated alcohol or ether species are unlikely to exist in these media either.) Thus, the reaction of the intermediate going to product or exchanged reactant is a general-acid-catalyzed process for esters. For amide hydrolysis, the situation is complicated by the fact that another, different, mechanism takes over in more strongly acidic media, according to the excess acidity plots. Some possibilities for this are given.Key words: esters, amides, benzimidates, hydrolysis, excess acidity, mechanism, acid media.

scholarly journals A super-cusp divertor configuration for tokamaks

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
D. D. Ryutov
Keyword(s):  
Control System ◽  
Poloidal Field ◽  
Practical Applications ◽  
Geometrical Features ◽  
Flux Expansion ◽  
The Way

This study demonstrates a remarkable flexibility of advanced divertor configurations created with the remote poloidal field coils. The emphasis here is on the configurations with three poloidal field nulls in the divertor area. We are seeking the structures where all three nulls lie on the same separatrix, thereby creating two zones of a very strong flux expansion, as envisaged in the concept of Takase’s cusp divertor. It turns out that the set of remote coils can indeed produce a cusp divertor, with additional advantages of: (i) a large stand-off distance between the divertor and the coils and (ii) a thorough control that these coils exert over the fine features of the configuration. In reference to these additional favourable properties acquired by the cusp divertor, the resulting configuration could be called ‘a super-cusp’. General geometrical features of the three-null configurations produced by remote coils are described. Issues on the way to practical applications include the need for a more sophisticated control system and possible constraints related to excessively high currents in the divertor coils.

Modeling Hydrocarbon Processing

2006 ◽  
Vol 3 (1) ◽  
Author(s):  
Teh C Ho
Keyword(s):  
Low Cost ◽  
Petroleum Industry ◽  
Operating Conditions ◽  
Process Models ◽  
Market Demand ◽  
Practical Applications ◽  
Hydrocarbon Processing ◽  
Minimum Capital ◽  
Microscopic Interactions ◽  
The Way

Driven by the global competition and market demand, the petroleum industry is under increasing pressure to produce clean, high-value products from low-cost feedstocks with minimum capital outlays. This has triggered an urgent need to develop robust process models capable of predicting the effects of feedstock composition, operating conditions, and catalyst properties on product quality. To develop such models, one generally splits the reaction mixture at the molecular level, examines microscopic interactions among individual reactions, and then works all the way up to the macroscopic level. Along the way one performs lumping to keep the size and complexity of the problem at bay. This is not only crucial for practical applications, but also important for fundamental understanding, since one does not want to lose sight of the forest for too many trees. This paper gives an overview of new and emerging theoretical tools for building kinetic models for hydrocarbon processing. While the emphasis is on reaction kinetics, the question of reducing hydrodynamic complexities is addressed as well.

scholarly journals Mechanisms of Thioacylal Hydrolysis in Sulfuric Acid Solutions

1975 ◽  
Vol 53 (18) ◽  
pp. 2772-2780 ◽  
Author(s):  
Robert Allan McClelland
Keyword(s):  
Sulfuric Acid ◽  
Nitro Compound ◽  
Ester Hydrolysis ◽  
Acid Solutions ◽  
Hydrolysis Mechanism ◽  
Acid Catalyzed ◽  
Sulfuric Acid Solutions ◽  
Electron Withdrawing Substituents

The acid-catalyzed hydrolysis (aqueous H2SO4) of thioacylalsCH3SCH2OAc and ArSCH2OAc is reported. The former is shown to react solely by an A-1 mechanism proceeding via an intermediate CH3SCH2+ cation. In the latter series hydrolysis in dilute acids involves both this A-1 mechanism and a normal AAc-2 ester hydrolysis mechanism occurring simultaneously; as the acidity is increased the proportion of A-1 reaction increases until it completely dominates. The A-1 reaction shows lesser importance with electron-withdrawing substituents. The 4-nitro compound in fact shows no A-1 mechanism until about 40% H2SO4. These hydrolyses are compared with those of the corresponding acylals, which show a similar mechanistic behavior. Relative A-1 reactivities for RXCH2OAc, RX = CH3O, CH3S, C6H5S, C6H5O are 81, 49, 1, 0.022, relative to C6H5SCH2OAc. Discussions pertaining to the effects of the oxygen and the sulfur in these systems are presented.

scholarly journals A Review of Teaching Qualitative Research: Strategies for Engaging Emerging Scholars

2019 ◽  
Author(s):  
Jason DeHart
Keyword(s):  
Qualitative Research ◽  
Research Projects ◽  
Research Strategies ◽  
Practical Applications ◽  
Qualitative Work ◽  
Salient Features ◽  
Depth And Complexity ◽  
The Way

This review highlights salient features of the book, Teaching Qualitative Research: Strategies for Engaging Emerging Scholars. The review notes the practical applications of the book, including the advice that the book’s authors offer about beginning research projects. Of particular note in the review is the way the authors balance a classroom introductory approach to qualitative work, while also giving attention to the depth and complexity of the methodologies that are used.

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