Zur Theorie der mechanischen Relaxation des Eises

Bass, R.

doi:10.1007/bf01342876

Cited by 28 publications

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“…Whalley & Davidson (1965) suggested from the A V data a higherorder transition at about -40 °C. This implied temperature-dependent state of partial proton order is a novel feature among the ice structures; its closest parallel is the stress-induced partial proton order proposed to account for the elastic relaxation of ice I (Bass, 1958). The variation of A V, AE, and AS along the I-III equilibrium curve is quite unlike the near constancy of these quantities along most of the other ice-ice-equilibrium curves.…”

Section: Thermodynamic Evidence Of Proton Ordermentioning

confidence: 71%

Structure of ice III

Kamb¹,

Prakash²

1968

Acta Crystallogr B Struct Crystallogr Cryst Chem

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Ice III, least dense of the high pressure forms of ice (0c= 1.160 g.cm-3 at -175°C, 1 atm), has a tetragonal structure (P41212, a= 6.73, c= 6.83/~,) involving a tetrahedrally linked H-bond framework with mean bond length 2.775 A.. The increase in density relative to ice I (0-94 g.cm-3) is accomplished by distortions from ideal tetrahedral coordination which allow two or three non-bonded neighbors to approach each water molecule to distances of about 3.6 A, much closer than the corresponding distance of 4.50/~ in ice I. The ice III framework has numerous five-ring connections, whereas only six-rings (and larger) are present in ice I; it is topologically analogous to the framework in silica-K, but corresponding structural parameters in the two analogs differ markedly. One O • • • O • • • O coordination angle in ice III has the extraordinarily large value 143 °. This should cause a marked destabilization of the water molecule orientation presented into this angle, and could lead to proton ordering at lower temperatures, for which there is some independent physical evidence. The X-ray data refine to R= 0.051 for a half-hydrogen (disordered) model, and to R = 0.057 for one of the four full-hydrogen (ordered) proton arrangements possible in P41212. Although the difference between these results is not statistically significant, the crystallographic evidence is weighted in favor of the half-hydrogen model. The protonordered arrangement admitted as an alternative by the X-ray data utilizes the most favorable watermolecule orientations available in the structure.

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Section: Thermodynamic Evidence Of Proton Ordermentioning

confidence: 71%

Structure of ice III

Kamb¹,

Prakash²

1968

Acta Crystallogr B Struct Crystallogr Cryst Chem

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“…Levi et al suggest that the concentration de pendence of the conductivity may be attributed to a difference in cationic and anionic distribution coefficients. (Their numerical values for these coefficients are higher by orders of magnitude than those mentioned Numbers (1)(2)(3)(4) relate these curves to data given in Table V earlier in this paper, because they are effective rather than interface co efficients. ) In their results, Levi et al see evidence that the conductivity of pure ice is one-half or one-third of that previously assumed (a view shared by Camp et al,20) and that the proton mobility is from one-fourth…”

Section: Letters Subscriptsmentioning

confidence: 90%

“…Mechanical relaxation in pure and doped ice was investigated experimentally (136) and theoretically (4). Re laxation occurs in the frequency range of the dielectric Debye dispersion, but the variation in the measured quantity (logarithmic decrement) is only about 1/100 of that for dielectric measurements, The relaxation time, τ, is given by identical, within experimental uncertainty, with the dielectric Debye re laxation time (Table III).…”

Section: Miscellaneous Investigationsmentioning

confidence: 98%

Some Effects of Trace Inorganics on the Ice/Water System

Gross

1968

Trace Inorganics in Water

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Trace inorganic impurities cause specific changes in the con ductivity, dielectric constant and dielectric relaxation, ther moelectric power, mechanical relaxation, and the microstruc ture of ice. Most of these effects are explained by changes in the populations of ion defects and valence defects. The freezing potential (Workman-Reynolds effect) occurs when trace amounts (10 -6 M to 10 -3 M) of many inorganic and some organic salts are present in a freezing solution. Selec tive ion incorporation induces a charge layer at the advanc ing phase boundary. Its effect on the overall distribution of impurities between the phases is probably small. The dis tribution coefficient increases with freezing rate. For a given ion species and freezing rate it is a function of all im purity species present in solution, their concentrations, and the shape and surface structure of the phase boundary. Typical values of distribution coefficients for ionic solutes in ice range from 10 -5 to 10 -3 . Traceinorganics are the cause of specific electrochemical phenomena at the phase boundary of growing ice; these are the freezing potential and the preferential incorporation into the solid phase of certain ions over others. The physical and chemical properties of the phases are more or less deeply affected by such interface processes. These processes raise fundamental questions concerning the mechanisms by which solute ions are incorporated into the ice structure and what their positions and effects are once they get there. This paper proposes to review these phenomena, the experimental evidence available, and the theories that have been formulated to account for them. A major difficulty in the critical evaluation of the data is their great sensitivity to the experimental conditions, which are difficult to define completely in most instances.

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“…The relaxation peak is generally considered in terms of the reorientation of water molecules during the application of cyclic stress (Bass, 1958;Gosar, 1974). This peak is described by the well known Debye relation.…”

Section: Journal Of Glac10looymentioning

confidence: 99%

Inelastic Behaviour of Ice Ih Single Crystals in the Low-Frequency Range Due to Dislocations

Vassoille¹,

Maï²,

Pérez³

1978

J. Glaciol.

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ABSTRACT. The inelas ti c beh avioW' of ice Ih single crystals has bee n in ves tiga ted by an inverted torsional pe ndulum in the low-freque ncy ra nge. T hree features a re distinguish ed : (i) a relaxation peak prev io usly observed by severa l a uthors in the higher-frequency range, (ii ) a n internal friction in creas ing with tempera ture in the high-te mperature range (230-273 K ), (iii ) within this high-temperatur e ra nge, inte rn a l fri ction becom es a mplitude dependent, and this dependence becomes greater the greater the te mperature. In this case, the intern al fri ctio n h as been interpreted in terms of movements of dislocatio ns. H ence, the experime nta l resul ts a re inte rpreted with a model of in ternal fri ction based on an empiri cal relation fo r the velocity of dislocations. Th is m odel of interna l fri ctio n is in fair agreement with ex perim e ntal data. I t is possibl e then to get a n es tim a te of dislocation de nsi ty. H ence it is sh own that intern al fri ction experiments ca n be useful in the stud y o f th e p lasti c behaviour o f ice single crys ta ls. R ESUME. R ole des dislocatiolls dalls le com/Jortement ineLastique basse Jrtfquence de La glace Ih . L e comportement inelast ique d e la glace Ih mon ocristalline a ete etudie it l'aide d' un pend ul e de torsion in ve rse fonctionn a nt da ns le dom a in e des basses frequences. 11 a ppa rait trois ca racteristiqu es:(i) un pi c de relaxation obser ve precedemme nt p ar d ivers a uteurs d a ns le domaine d es h a utes frequences, (ii ) un fro ttement inter ie ur croissant ra pidem e nt avec la temperatu re dans le domain e 230-273 K , (iii ) d a ns ce domain e d e te mperatures, le fro tte m e nt interieur depend de I'ampli tud e de deformation et ce tte dependance est d 'a utant plus forte q u e la te mpera ture es t plus elevee. Nous nous som mes plus pa rticuli erement interesses d a ns ce travail a u co mportement d e la glace monocristallin e dans le doma in e des h a utes tempera tures e n metta nt en evidence le role des d islocations. La compa ra ison d e nos resulta ts avec ceux obtenus par topogra phie d e rayo ns X nous p erm et d ' interprt: tcr l' cnsembl e d es donn ees a pportees pa r le frotte me nt inte rieur. 11 est a lors poss ibl e d' obte n ir une estimation de la d e nsite d e dislocatio n. II appara it ainsi que les m es ures de fro ttement in terieur peuvent e t re utiles pour I'etud e d e la d eform a tio n p lastique de la glace. Z USAMM ENFASSUNG. Anela stisches Verhalttll VOIl Eis-lh-Einkristalle n im Niedeifrequell z bereich auJgnmd VOIlVersetz llll.gen. D as a nel as tisch e V e rha lten von E is-Ih-Einkrista ll en wurde mit einem umge ke h rten Torsionspendel im N iederfreq uenzbereich untersucht. Drei Merkmale werden h e ra usgeslell t:(i) Ein Rclaxa Li onsdampfu ngsmaximum, d as b e reits frUh er von verschi edenen Ve rfassern im h6heren Frequenzbereich beobachte t wurde. (ii ) E in Anstieg der inne re n R eibun g mit de r T e mperatur im H ochte mpera turbereich (230-273 K ). (iii) Inn...

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Zur Theorie der mechanischen Relaxation des Eises

Cited by 28 publications

References 0 publications

Structure of ice III

Structure of ice III

Some Effects of Trace Inorganics on the Ice/Water System

Inelastic Behaviour of Ice Ih Single Crystals in the Low-Frequency Range Due to Dislocations

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