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Macroscopic thermodynamics of flowing polymeric liquids (1999)

Dressler, Marco ; Edwards, Brian J. ; Öttinger, Hans Christian

Springer

Rheologica acta 38 (1999), S. 117-136

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ISSN: 1435-1528

Keywords: Key words Non-isothermal flows ; Polymeric liquids ; Thermodynamics ; Non-Newtonian fluids

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Physics

Notes: Abstract The thermodynamics and mechanics of non-isothermal polymeric fluids are examined within the auspices of a new methodology wherein the laws of physics and principles of mechanics which are applicable to these thermodynamic systems are imbedded in a definite mathematical structure of a general, abstract equation. Such a concept allows new insight to be obtained concerning some aspects of non-isothermal flows of polymeric fluids, and permits a consistent expression and interpretation of other thermodynamic theories for these systems which have been developed over the past forty years. A major portion of this article is devoted to demonstrating the above statements, and in so doing some common misconceptions occurring in a significant fraction of the literature regarding this subject are exposed. The definite mathematical structure of the new methodology permits the thermodynamically consistent generalization of isothermal, incompressible models of polymeric fluids to non-isothermal, compressible conditions. Doing thus reproduces, corrects, and extends non-isothermal models which have been developed over the years, and also allows for simpler (but equivalent) representations of these models in terms of alternate variables with a clearer connection to the microstructure of the material than the stress tensor and heat flux vector fields. Furthermore, a generalization of the GENERIC structure is proposed that accommodates interactions between phenomena of differing parities, which impose antisymmetry upon the corresponding elements of the dissipative operator matrix.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s003970050162

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Cobalt, chromium, and nickel concentrations in body fluids of patients with porous-coated knee or hip prostheses (1989)

Sunderman, F. William ; Hopfer, Sidney M. ; Swift, Thomas ; [et al.]

Hoboken, NJ [u.a.] : Wiley-Blackwell

Journal of Orthopaedic Research 7 (1989), S. 307-315

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ISSN: 0736-0266

Keywords: Cobalt ; Chromium ; Nickel ; Total knee arthroplasty ; Total hip arthroplasty ; Prostheses, porous-coated ; Life and Medical Sciences

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine

Notes: Co, Cr, and Ni concentrations were determined by electrothermal atomic absorption spectrophotometry in serum and urine specimens collected from a group of 28 patients at intervals of from 1 day to 2.5 years after total knee or hip arthroplasty with porous-coated prostheses fabricated of Co-Cr alloy (ASTM F-75-82). Two control groups were also tested: (a) 42 healthy adults and (b) 16 orthopaedic patients after total knee or hip arthroplasty with porous-coated prostheses fabricated predominantly of Ti-Al-V alloy (ASTM F-136-84). All prostheses contained polyethylene components to avoid metal-to-metal contact. Mean Co concentrations in serum and urine were slightly increased in patients with Co-Cr knee implants at 6-120 weeks after surgery, compared with (a) preoperative values, (b) corresponding values in patients with Co-Cr hip implants, and (c) corresponding values in control patients with Ti-Al-V knee and hip prostheses. Substantially increased Co levels were observed in serum and urine of two patients at 7 weeks and 22 months postarthroplasty, associated with loosening of the prostheses; one of the patients also had elevated Cr levels in serum and urine. Although ASTM F-75-82 and F-136-84 alloys contain very little Ni (〈1.0 and 〈0.2% Ni, respectively, by wt), mean Ni concentrations in serum and urine were greatly increased at 1-2 days after implantation of Ti-Al-V and Co-Cr prostheses, diminishing by 2 weeks. The postoperative hypernickelemia and nickeluresis may reflect contamination of the operative field with Ni-containing particles from the drills, cutting jigs, and drilling jigs, or it may represent a previously unrecognized pathophysiological response to surgery.

Additional Material: 2 Ill.