Molecular Structure and Properties of Polybutadiene Rubbers

1964 ◽  
Vol 37 (2) ◽  
pp. 408-433 ◽  
Author(s):  
H. Blümel
Keyword(s):  
Molecular Structure ◽  
Natural Rubber ◽  
Structural Characteristics ◽  
Molecular Structures ◽  
Structure And Properties ◽  
Technological Properties ◽  
Starting Point ◽  
Mixing Behavior ◽  
Basic Characteristics ◽  
The One

Abstract A discussion of the development, present day applications, and the advantages of polybutadienes are presented. The variations of an over-all concept in products obtained through different preparations and having various molecular structures as well as differing service and technological properties were made the starting point for the present investigations. Section 2 provides a review of the basic characteristics of the most important processes for preparing polybutadiene and the associated structural or compositional characteristics. Fourteen typical polybutadienes encompassing the entire range of polybutadienes are compared to cold rubber and natural rubber with respect to their most importance analytical and polymer values corresponding to their arrangement into preparation groups. The correlations between the technological properties of the raw rubbers, of the compounds, including the mixing behavior, and the vulcanizates on the one hand and the molecular structure composition of the rubbers upon which they are based, on the other, are discussed using detailed synopses in Sections 3 and 4. In doing this, it was important to see the principal features of the different polybutadienes compared to one another, effects of the structural characteristics and of additives on the properties of the raw rubbers, compounds, and vulcanizates, as well as the differences encountered as compared to polymers which are considered most important for use in blends (cold SBR and natural rubber). Finally, in Section 5, in summary form, the effects were treated of the individually appearing structural and compositional factors in the initial polymers on the service and technological properties of the raw rubbers, compounds, and vulcanizates.

scholarly journals Computational Nanochemistry Study of the Molecular Structure and Properties of Chlorophyll a

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Mónica Alvarado-González ◽  
Norma Flores-Holguín ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Molecular Structure ◽  
Chlorophyll A ◽  
Active Sites ◽  
Chemical Reactivity ◽  
Molecular Structures ◽  
Structure And Properties ◽  
Reactivity Descriptors ◽  
Koopmans Theorem ◽  
Td Dft ◽  
Chemical Reactivity Descriptors

The M06 family of density functionals has been assessed for the calculation of the molecular structure and properties of the chlorophyll a molecule. Besides the determination of the molecular structures, the UV-Vis spectra have been computed using TD-DFT in the presence of a solvent, and the results were compared with the experimental data available. The chemical reactivity descriptors have been calculated through conceptual DFT. The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices. A comparison between the descriptors calculated through vertical energy values and those arising from the Koopmans' theorem approximation have been performed in order to check for the validity of the last procedure.

scholarly journals Development of Meat Products with Healthier Lipid Content: Vibrational Spectroscopy

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 341
Author(s):  
Claudia Ruiz-Capillas ◽  
Ana M. Herrero
Keyword(s):  
Vibrational Spectroscopy ◽  
Lipid Content ◽  
Structural Characteristics ◽  
Structured Lipids ◽  
Meat Products ◽  
Future Research ◽  
Bulking Agents ◽  
Negative Consequences ◽  
Technological Properties ◽  
The One

This review focuses on the importance of developing meat products with healthier lipid content and strategies such as the use of structured lipids to develop these enriched products. The review also conducts a critical analysis of the use of vibrational spectroscopy as a tool to further these developments. Meat and meat products are extensively recognized and consumed in the world. They are an important nutritional contribution in our diet. However, their consumption has also been associated with some negative consequences for health due to some of its components. There are new trends in the design of healthy meat products focusing mainly on improving their composition. From among the different strategies, improving lipid content is the one that has received the most attention. A novel development is the formation of lipid materials based on structured lipids such emulsion gels (EGs) or oil-bulking agents (OBAs) that offer attractive applications in the reformulation of health-enhanced meat products. A deeper interpretation is required of the complicated relationship between the structure of their components and their properties in order to obtain structured lipids and healthier meat products with improved lipid content and acceptable characteristics. To this end, vibrational spectroscopy techniques (Raman and infrared spectroscopy) have been demonstrated to be suitable in the elucidation of the structural characteristics of lipid materials based on structured lipids (EGs or OBAs) and the corresponding reformulated health-enhanced meat products into which these fat replacers have been incorporated. Future research on these structures and how they correlate to certain technological properties could help in selecting the best lipid material to achieve specific technological properties in healthier meat products with improved lipid content.

scholarly journals Triphenylstannyltris(trimethylphosphan)cobalt - Molekülstruktur und Eigenschaften / Triphenylstannyltris(trimethylphosphane)cobalt -Molecular Structure and Properties

1983 ◽  
Vol 38 (3) ◽  
pp. 303-310 ◽  
Author(s):  
Hans-Friedrich Klein ◽  
Klaus Ellrich ◽  
Dietmar Neugebauer ◽  
Olli Orama ◽  
Karl Krüger
Keyword(s):  
Molecular Structure ◽  
Single Crystals ◽  
Molecular Structures ◽  
Structure And Properties ◽  
Crystal And Molecular Structures ◽  
Tetrahedral Molecules ◽  
Small Ligands

AbstractPotassium cobaltates K+CoLsL' -(L = Me3P, L' = N2, olefin) react with SnCl(C6H5)3 or GeBr(CeH5)3 to give tetracoordinate complexes containing Co-Sn and Co-Ge bonds. Crystal and molecular structures of two single crystals were determined. They show tetrahedral molecules Co[Sn(C6H5)3][P(CH3)3]3 in different packing order. Both tetra-coordinate compounds take up small ligands thereby completing their 18-electron valence shells in compounds Co[E(C6H5)3]L3L' (L = (CH3)3P; E = Ge, L' = CO; E = Sn, L' = CO, C2H4). A sparingly soluble paramagnetic adduct Co[Sn(C6H5)3]L4 is believed to contain a tin-bonded phosphane.

Entrepreneurship Management at the Local Government Level: The Experience of the Cities for Entrepreneurs Program

2018 ◽  
Vol 9 (5) ◽  
pp. 388-407
Author(s):  
Patricio Gigli ◽  
◽  
Donatela Orsi ◽  
Marisel Martín Aramburú ◽  
◽  
...  
Keyword(s):  
Human Capital ◽  
Local Government ◽  
Local Governments ◽  
Structural Characteristics ◽  
National Level ◽  
Development Issue ◽  
Starting Point ◽  
Local Government Level ◽  
Micro Level ◽  
Government Level

This paper aims at describing the experience of the Cities for Entrepreneurs Program (Ciudades para Emprender or CPE) of the National Directorate of Community and Human Capital (which belongs to the SEPYME), National Ministry of Production. This paper starts from the premise that entrepreneurship takes place at the most micro level of the offer and, therefore, is a concept associated with the characteristics of the environment closest to that offer: the local territory. However, there is little history in the country of public policies relating the issue of entrepreneurship with the local management. That is why we take as a starting point the conceptualization of the chosen framework: local governments and the development issue, seen from the perspective of entrepreneurships. Moreover, an overview is given on the structural characteristics of municipalities in Argentina. In addition, some international experiences and attempts to promote entrepreneurship at a national level are analyzed. Finally, the Cities for Entrepreneurs Program (CPE) is outlined, based on a summary of the diagnoses of the Entrepreneurial Ecosystems of the selected cities and the tools used and their execution status at the time of publication of this paper.

scholarly journals Practices of sustainability and the enactment of their natures/cultures: Ecosystem services, rights of nature, and geoengineering

2021 ◽  
pp. 053901842199894
Author(s):  
Frank Adloff ◽  
Iris Hilbrich
Keyword(s):  
Ecosystem Services ◽  
Latin American ◽  
Social Systems ◽  
The Earth ◽  
Starting Point ◽  
Knowledge Cultures ◽  
Rights Of Nature ◽  
Value Of Nature ◽  
The One ◽  
And Control

Possible trajectories of sustainability are based on different concepts of nature. The article starts out from three trajectories of sustainability (modernization, transformation and control) and reconstructs one characteristic practice for each path with its specific conceptions of nature. The notion that nature provides human societies with relevant ecosystem services is typical of the path of modernization. Nature is reified and monetarized here, with regard to its utility for human societies. Practices of transformation, in contrast, emphasize the intrinsic ethical value of nature. This becomes particularly apparent in discourses on the rights of nature, whose starting point can be found in Latin American indigenous discourses, among others. Control practices such as geoengineering are based on earth-systemic conceptions of nature, in which no distinction is made between natural and social systems. The aim is to control the earth system as a whole in order for human societies to remain viable. Practices of sustainability thus show different ontological understandings of nature (dualistic or monistic) on the one hand and (implicit) ethics and sacralizations (anthropocentric or biocentric) on the other. The three reconstructed natures/cultures have different ontological and ethical affinities and conflict with each other. They are linked to very different knowledge cultures and life-worlds, which answer very differently to the question of what is of value in a society and in nature and how these values ought to be protected.

scholarly journals Development, Validation and Application of a UHPLC-MS Method for the Quantification of Chios Mastic Gum Triterpenoids in Human Plasma

Planta Medica ◽  
2021 ◽  
Author(s):  
Vincent Brieudes ◽  
Eleni V. Mikropoulou ◽  
Errikos Kallergis ◽  
Andriana C. Kaliora ◽  
Efstathia Papada ◽  
...  
Keyword(s):  
Human Plasma ◽  
Biological Fluids ◽  
Structural Characteristics ◽  
Biological Properties ◽  
Lipid Lowering ◽  
High Yield ◽  
Limit Of Quantification ◽  
Isolation And Characterization ◽  
Starting Point ◽  
Chios Mastic Gum

AbstractChios mastic gum is the resinous secretion obtained from the barks of the shrub Pistacia lentiscus var. Chia, which is endemic to the Greek island of Chios. Since antiquity, Chios mastic gum has found several uses as a phytotherapeutic remedy, primarily for the treatment of gastrointestinal disorders while recently, Chios mastic gum was also recognized by EMA as an herbal medicinal product with specific indications. Chios mastic gumʼs biological properties are attributed to triterpenes which comprise the major chemical group (approx. 70%) and notably isomasticadienonic acid and masticadienonic acid. However, due to their structural characteristics, the isolation thereof in high yield and purity is challenging and since they are not commercially available, pharmacological studies aiming to assess their biological properties are limited. In the present work, masticʼs phytochemical investigation by UPLC-HRMS is followed by the isolation and characterization of isomasticadienonic acid and masticadienonic acid to be used as analytical standards for their accurate and reliable quantification in human plasma. A UHPLC-tQ-MS method that was developed and validated (in terms of specificity, linearity, limit of quantification, accuracy and precision), for the direct quantification of the targeted compounds in the low ng/mL range of concentration, was subsequently implemented on plasma samples of healthy volunteers thus demonstrating its fitness for purpose. The results presented herein might provide insight to the understanding of this traditional natural product consumed notably for its anti-inflammatory, antioxidant and lipid lowering properties. Moreover, this method might serve as a starting point for any study aiming to monitor bioactive triterpenes in biological fluids.

Ontology and Perception

2004 ◽  
Vol 5 (1) ◽  
pp. 43-58
Author(s):  
Jeffrey S. Galko ◽  
Keyword(s):  
Common Sense ◽  
The Other ◽  
Cognitive Capacity ◽  
Complex Environment ◽  
Starting Point ◽  
Ontological Question ◽  
The One ◽  
Bodies Of Water ◽  
The Relationship

The ontological question of what there is, from the perspective of common sense, is intricately bound to what can be perceived. The above observation, when combined with the fact that nouns within language can be divided between nouns that admit counting, such as ‘pen’ or ‘human’, and those that do not, such as ‘water’ or ‘gold’, provides the starting point for the following investigation into the foundations of our linguistic and conceptual phenomena. The purpose of this paper is to claim that such phenomena are facilitated by, on the one hand, an intricate cognitive capacity, and on the other by the complex environment within which we live. We are, in a sense, cognitively equipped to perceive discrete instances of matter such as bodies of water. This equipment is related to, but also differs from, that devoted to the perception of objects such as this computer. Behind this difference in cognitive equipment underlies a rich ontology, the beginnings of which lies in the distinction between matter and objects. The following paper is an attempt to make explicit the relationship between matter and objects and also provide a window to our cognition of such entities.

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