The Role of Concepts of Structure in the Development of the Physical Chemistry of Polymers

Isis ◽  
1981 ◽  
Vol 72 (3) ◽  
pp. 446-456 ◽  
Author(s):  
L. M. Pritykin
Keyword(s):  
Physical Chemistry

The role of bile composition and physical chemistry in the pathogenesis of octreotide-associated gallbladder stones

1994 ◽  
Vol 107 (5) ◽  
pp. 1503-1513 ◽  
Author(s):  
S. Hyder Hussaini ◽  
Gerard M. Murphy ◽  
Colette Kennedy ◽  
G. Michael Besser ◽  
John A.H. Wass ◽  
...  
Keyword(s):  
Physical Chemistry ◽  
Bile Composition ◽  
Gallbladder Stones

Translating across macroscopic, submicroscopic, and symbolic levels: the role of instructor facilitation in an inquiry-oriented physical chemistry class

2015 ◽  
Vol 16 (4) ◽  
pp. 769-785 ◽  
Author(s):  
Nicole Becker ◽  
Courtney Stanford ◽  
Marcy Towns ◽  
Renee Cole
Keyword(s):  
Physical Chemistry ◽  
Mathematical Problem ◽  
Class Discussion ◽  
Graphical Representations ◽  
Guided Inquiry ◽  
Instructional Context ◽  
Curricular Materials ◽  
Toulmin’S Model

In physical chemistry classrooms, mathematical and graphical representations are critical tools for reasoning about chemical phenomena. However, there is abundant evidence that to be successful in understanding complex thermodynamics topics, students must go beyond rote mathematical problem solving in order to connect their understanding of mathematical and graphical representations to the macroscopic and submicroscopic phenomena they represent. Though traditional curricular materials such as textbooks may provide little support for coordinating information across macroscopic, submicroscopic, and symbolic levels, instructor facilitation of classroom discussions offers a promising route towards supporting students' reasoning. Here, we report a case study of classroom reasoning in a POGIL (process-oriented guided inquiry learning) instructional context that examines how the class coordinated macroscopic, submicroscopic, and symbolic ideas through classroom discourse. Using an analytical approach based on Toulmin's model of argumentation and the inquiry-oriented discursive moves framework, we discuss the prevalence of macroscopic, submicroscopic and symbolic-level ideas in classroom reasoning and we discuss how instructor facilitation strategies promoted reasoning with macroscopic, submicroscopic, and symbolic levels of representation. We describe one sequence of instructor facilitation moves that we believe promoted translation across levels in whole class discussion.

Physical Chemistry of Crosslinking

1976 ◽  
Vol 46 (5) ◽  
pp. 329-342 ◽  
Author(s):  
G. L. Madan ◽  
S. B. Patel ◽  
N. T. Baddi ◽  
P. C. Mehta
Keyword(s):  
Physical Chemistry ◽  
Crosslinking Agent ◽  
Crosslinking Reaction ◽  
Solution Properties ◽  
Urea Derivatives ◽  
Structure Solution ◽  
Catalyst Temperature ◽  
Enthalpy And Entropy ◽  
Kinetics Of

Crosslinked cotton fabrics suffer significant losses in strength and abrasion resistance. In order to understand why these losses occur and also to reduce them, the physical chemistry of the process of crosslinking and the role of adsorption in the crosslinking reaction were studied. An attempt is made to relate adsorption and reactivity of different cyclic urea derivatives (DMEU, DMPU, DHEU, and DMDHEU) to the molecular structure, solution properties, pH, nature and concentration of catalyst, temperature, and time of reaction. Solution properties of crosslinking compounds were determined from measurements of electrical conductivity and the depression of the freezing points of aqueous solutions of the crosslinking compounds. A study on chemisorption with different cyclic urea derivatives showed that the maximum chemisorption takes place at pH 2.5 with DMEU and DMPU, and at 0.8 and zero pH with DHEU and DMDHEU, respectively. The kinetics of chemisorption in these crosslinking compounds revealed that the amount of DMEU and DMPU chemisorbed increases initially with time and then decreases and finally reaches an equilibrium value. The chemisorption of DHEU and DMDHEU increase with time and finally reach an equilibrium value. The data show that the chemisorption of these crosslinking compounds are pseudo first-order reactions with respect to the concentration of the crosslinking agent. Equilibrium physical and chemisorption for all the four crosslinking compounds were studied and found to be of the Langmuir type. The thermodynamic parameters such as affinity, enthalpy, and entropy of chemisorption were calculated. The saturation value for different crosslinking compounds are found to be in the order DMEU > DMPU > DHEU > DMDHEU.

The Philosophical Importance of the Periodic Table

2018 ◽  
Author(s):  
Mark Weinstein
Keyword(s):  
Physical Chemistry ◽  
Periodic Table ◽  
Social Issues ◽  
Scientific Practice ◽  
Biomedical Sciences ◽  
Track Record ◽  
Standard Models ◽  
Number Of Publications ◽  
Philosophical Importance

The Centrality of the periodic table to chemistry is beyond dispute. What seems just as obvious to me is that the table should be seen to play an equally central role in the philosophical understanding of scientific inquiry. This may be a minority opinion; if we look at philosophical discussions of scientific issues broadly, such a view seems unsupported by philosophical practice. Philosophers have been exercised by the problematic aspects of science: revolutions rather than normal scientific practice; aspects of science that are conceptually problematic, for example, quantum mechanics; areas of science that include explanatory accounts that deviate from standard models, for example, evolutionary theory; or aspects of science that raise moral or social issues, such as the biomedical sciences. Chemistry, with a long track record of unsurprising growth, with myriad of applications taken for granted, and with a strongly supported and unifying theory may seem to be just too boring to exercise philosophers interested in resolving puzzles, developing surprising theories, and engendering novel insights. But as I will attempt to show, the most normal of normal sciences, physical chemistry with the periodic table at its core, offers a view of science relevant to central philosophical concerns. In what follows I will offer an overview of three philosophical areas for which the periodic table is salient, while indicating a logical image of a scientific structure of the sort that the table exemplifies. I look first at methodology, and in particular the role of counterevidence in evaluating generalizations. Second I look at how the table permits a reinterpretation of foundational epistemological notions of truth. Finally, I will look at ontology, how the table supports our commitment to the fundamental nature of reality. The basis of my analysis is a model of emerging truth (MET). This metamathematical model is available in a number of publications and I will include only its most basic elements in a technical appendix. In place of the formal construction I will offer the philosophical intuitions it encodes, intuitions that draw upon the structure of chemistry with the periodic table at its core.

Role of physical chemistry in stratigraphic problems

1937 ◽  
Vol 32 (5) ◽  
pp. 533-549 ◽  
Author(s):  
George Rogers Mansfield
Keyword(s):  
Physical Chemistry
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