Group Contribution Revisited: The Enthalpy of Formation of Organic Compounds with “Chemical Accuracy” Part II

Group contribution (GC) methods to predict thermochemical properties are eminently important to process design. We present a group contribution parametrization for the heat of formation of organic molecules exhibiting chemical accuracy, maximum 1 kcal/mol (4.2 kJ/mol) difference between experiment and model values while minimizing the number of parameters avoiding overfitting and therewith avoiding reduced predictability. Compared to the contemporary literature, this was successfully achieved by employing available literature high-quality and consistent experimental data, optimizing parameters group by group, and introducing additional parameters when chemical understanding was obtained supporting these. A further important result is the observation that the applicability of the group contribution approach breaks down with increasing substitution levels, i.e., more heavily alkyl-substituted molecules, the reason being a serious influence of substitution on the conformation of the flexible part of the entire molecule within particular valence angles and torsional angles affected, which cannot be accounted for by additional GC parameters with fixed numerical values.

Failure analysis of flexible couplings by self-heating

Flexible couplings are applied in mechanical systems to reduce torsional vibrations. Failures in the flexible parts of the couplings are often incorrectly attributed to overloading of the couplings. The goal of the article is to prove by experimental analysis that self-heating occurs in flexible couplings. The self-heating of the flexible coupling and the consequent increase in the temperature of the flexible part is the cause of the failure. Experimental identification of self-heating was performed on three types of flexible couplings. Although these couplings are design different, they are used for a nominal torque of 150Nm.

Analysis of Structural and Semantic Characteristics of Agricultural Terms in the Translation Aspect

The article summarizes the theoretical experience of studying the structural and semantic characteristics of scientific and technical terms and agricultural terms in particular. It has substantiated the fact that the agrarian sphere is experiencing a rapid emergence of terms-innovations that are quickly passing all stages of structural-semantic assimilation. A significant percentage of terms are formed as a result of rethinking their previous meanings, which leads to the emergence of so-called semantic terms. Analysis of structural and semantic features of agricultural terms showed that their formation occurs through derivation, terminologization of common vocabulary and assimilation of borrowings. The paper also analyzes examples of the functioning of English-language multicomponent clusters and the peculiarities of their translation. The purpose of research is to clarify the structural and semantic features of agricultural terminology, to identify and describe the processes of formation of one- and multi-component agricultural terms, to determine the main word-forming types of agricultural terminology. Results of research. Agrarian terminology, which is a set of words and stable phrases corresponding to the concepts functioning in this area (objects, phenomena and actions), is a mobile and flexible part of common vocabulary, and therefore requires systematization. The main carriers of these concepts are nouns, a certain number of verbs and adjectives which most serve as definitions in multicomponent clusters and are not independent. Word-forming means are mainly Latin-Greek morphemes, word stems and phrases. Depending on the participation of language in term formation, the terms of the agricultural sector are divided into three types: simple terms or word-terms; complex terms; terms-phrases or multicomponent clusters Agrarian terminology uses such ways of word formation as lexical-semantic, lexical-syntactic, morphological, abbreviation, and morphological-syntactic. Many commonly used lexical items acquire meanings inherent in the agricultural sector, becoming terms with a narrower meaning. Modern scientific literature on agricultural topics contains terms that have two or more meanings in this area, the clarification of which is only disclosed by the context. In translation, such ambiguity causes blurring of meaning, vagueness, substitution of terms and ultimately distortion of the content as a whole. It is important to consider the lexical and grammatical environment of the term. Due to the context, the following translation issues can be addressed: a) the word is used in its common or special narrow meaning; b) the choice of one of several meanings of a polysemous term in a particular context. From agrarian vocabulary, terminological units move into colloquial language, sometimes becoming jargons or terminoids that function in limited areas of engineering and technology, forming a layer of stylized new scientific and technical terms. Professional slang is usually short, expressive and to some extent stylistically colored. The most successful of them are fixed in the terminology system over time and receive official recognition in a certain subject area, being fixed in dictionaries, and some pass to other areas and into the common language. Specifics of functioning the terminological combinations require appropriate methods of their translation, among which there are a few main ones: literal translation of lexical units is carried out with the help of calque; replacement of parts of speech; explanatory translation of terms; translation with word order changes, primarily in attributive group. Conclusions. Agro-biological terminology tends to be poly-variant in translation, polysemy and homonymy. In order to overcome the difficulties in translating professional texts, it is necessary to work more actively with special vocabulary, thoroughly study the issues of ambiguity, synonyms and antonyms, word formation and methods of translation. The above considerations open opportunities for the practical application of these methods of translation of agro-biological terminology, and for further creative search for the correct perception of professionally oriented texts.

Linguistic Study on the „Sandipa” Manuscript. Morphology (3.2.). Pronouns

The morphological peculiarities of the pronoun present in the text of the popular writing entitled Sandipa (ms. Rom. 824, dated in 1798 and kept at the State Library of the Russian Federation, Moscow) are analyzed. Being a flexible part of speech with several species (9), the pronoun is highlighted by a series of forms typical of both our first ancient texts and those developed in the second half of the eighteenth century, especially in recent decades. of the century, therefore contemporary with the handwritten version of the popular writing announced in the title.

Influence of Maxwell Stiffness in Damage Control and Analysis of Structures with Added Viscous Dampers

Viscous damping systems are often implemented in structures to reduce seismic damage. The stiffness of these elements is dominated by the most flexible part of the set including brace extender, auxiliary mounting elements and damping unit. Existing experimental data are used in this study to show that the actual stiffness of the set is about 25% to 50% of the value generally adopted in current engineering practice, which is based solely on the brace extender. A numerical study shows that this reduction has large implications for several variables related to damage control: residual drift ratio, storey acceleration and plastic strain energy dissipated by the frame members. Other variables, such as member forces and rotations, can experience large variations, particularly for non-linear dampers and high damping levels, especially in the top part of the building and more conspicuously for moderate earthquake intensities. In the absence of accurate data, Maxwell stiffness for analysis based on brace extender properties should be substantially reduced, with recommended factors between 0.25 and 0.50. Given the scarcity of experimental data, these results should be considered preliminary.

3D Multi-Material Printing of an Anthropomorphic, Personalized Replacement Hand for Use in Neuroprosthetics Using 3D Scanning and Computer-Aided Design: First Proof-of-Technical-Concept Study

Background: This paper presents a novel approach for a hand prosthesis consisting of a flexible, anthropomorphic, 3D-printed replacement hand combined with a commercially available motorized orthosis that allows gripping. Methods: A 3D light scanner was used to produce a personalized replacement hand. The wrist of the replacement hand was printed of rigid material; the rest of the hand was printed of flexible material. A standard arm liner was used to enable the user’s arm stump to be connected to the replacement hand. With computer-aided design, two different concepts were developed for the scanned hand model: In the first concept, the replacement hand was attached to the arm liner with a screw. The second concept involved attaching with a commercially available fastening system; furthermore, a skeleton was designed that was located within the flexible part of the replacement hand. Results: 3D-multi-material printing of the two different hands was unproblematic and inexpensive. The printed hands had approximately the weight of the real hand. When testing the replacement hands with the orthosis it was possible to prove a convincing everyday functionality. For example, it was possible to grip and lift a 1-L water bottle. In addition, a pen could be held, making writing possible. Conclusions: This first proof-of-concept study encourages further testing with users.

Advanced Education

Advanced education was the most flexible part of the scribal curriculum. It could be tailored to the particular specialty of the scribe: the palace, the temple, commerce, military, etc. The advanced curriculum was often taken from other spheres, such as temple hymns or rituals, and used for scribal study (much like the Gettysburg Address or the “Star-Spangled Banner” might be reused as part of a school curriculum). There is evidence of cuneiform literature including Gilgamesh, Adapa, and law codes like Hammurabi that have been excavated in the southern Levant dating to the second millennium BCE. This provides a tangible vector of transmission for these traditions into the early alphabetic scribal tradition.

Sampling Conformational Changes of Bound Ligands Using Nonequilibrium Candidate Monte Carlo

Flexible ligands often have multiple binding modes or bound conformations that differ by rotation of a portion of the molecule around internal rotatable bonds. Knowledge of these binding modes is important for understanding the interactions stabilizing the ligand in the binding pocket, and also for calculating accurate binding affinities. In this work, we use a hybrid molecular dynamics (MD)/non-equilibrium candidate Monte Carlo (NCMC) method to sample the different binding modes of several flexible ligands and also to estimate the population distribution of the modes. The NCMC move proposal is divided into three parts. The flexible part of the ligand is alchemically turned off by decreasing the electrostatics and steric interactions gradually, followed by rotating the rotatable bond by a random angle and then slowly turning the ligand back on to its fully interacting state. The alchemical steps prior to and after the move proposal help the surrounding protein and water atoms in the binding pocket relax around the proposed ligand conformation and increase move acceptance rates. The protein-ligand system is propagated using classical MD in between the NCMC proposals. Using this MD/NCMC method, we were able to correctly reproduce the different binding modes of inhibitors binding to two kinase targets -- c-Jun N-terminal kinase-1 and cyclin-dependent kinase 2 -- at a much lower computational cost compared to conventional MD and umbrella sampling. This method is available as a part of the BLUES software package.