Increase of the Coefficient of Static Friction Using Turn-milling with an Inclined Milling Spindle

AbstractThere is a strong need for surfaces with a high coefficient of static friction to meet the demands for increasing performance and lightweight construction strategies, especially regarding friction-locked connections. An auspicious turn-milling process used to generate protruding surface structures which lead to a high coefficient of static friction is investigated. The influence of the corner geometry on the surface structure is examined by machining end faces of specimens of the steel 42CrMo4+QT (1.7225). Experimental tests for the identification of the coefficient of static friction show a significant increase up to 275% (μ0.1° = 0.55) for turn-milled surfaces in comparison to unstructured specimens (μ0.1 ≈ 0.2)

Charge and momentum transfer in supercooled melts: Why should their relaxation times differ?

The steady state values of the viscosity and the intrinsic ionic-conductivity of quenched melts are computed, in terms of independently measurable quantities. The frequency dependence of the ac dielectric response is estimated. The discrepancy between the corresponding characteristic relaxation times is only apparent; it does not imply distinct mechanisms, but stems from the intrinsic barrier distribution for $\alpha$-relaxation in supercooled fluids and glasses. This type of intrinsic ``decoupling'' is argued not to exceed four orders in magnitude, for known glassformers. We explain the origin of the discrepancy between the stretching exponent $\beta$, as extracted from $\epsilon(\omega)$ and the dielectric modulus data. The actual width of the barrier distribution always grows with lowering the temperature. The contrary is an artifact of the large contribution of the dc-conductivity component to the modulus data. The methodology allows one to single out other contributions to the conductivity, as in ``superionic'' liquids or when charge carriers are delocalized, implying that in those systems, charge transfer does not require structural reconfiguration.Comment: submitted to J Chem Phy

Mesoscopic non-equilibrium thermodynamics approach to non-Debye dielectric relaxation

Mesoscopic non-equilibrium thermodynamics is used to formulate a model describing non-homogeneous and non-Debye dielectric relaxation. The model is presented in terms of a Fokker-Planck equation for the probability distribution of non-interacting polar molecules in contact with a heat bath and in the presence of an external time-dependent electric field. Memory effects are introduced in the Fokker-Planck description through integral relations containing memory kernels, which in turn are used to establish a connection with fractional Fokker-Planck descriptions. The model is developed in terms of the evolution equations for the first two moments of the distribution function. These equations are solved by following a perturbative method from which the expressions for the complex susceptibilities are obtained as a functions of the frequency and the wave number. Different memory kernels are considered and used to compare with experiments of dielectric relaxation in glassy systems. For the case of Cole-Cole relaxation, we infer the distribution of relaxation times and its relation with an effective distribution of dipolar moments that can be attributed to different segmental motions of the polymer chains in a melt.Comment: 33 pages, 6 figure

CDAT\u27s Memo in Support for Mtn SJ

The Coeur d\u27Alene tribe\u27s memorandu in support of Motion for Summary Judgmen

CDAT\u27s Memo in Support for Mtn SJ

The Coeur d\u27Alene tribe\u27s memorandu in support of Motion for Summary Judgmen

CDAT\u27s Reply Brief to State and other Objectors

Coeur d\u27Alene Tribe\u27s Reply to the State of Idaho\u27s and Objectors\u27 Response to Summary Judgment Motio

CDAT\u27s Reply Brief to State and other Objectors

Coeur d\u27Alene Tribe\u27s Reply to the State of Idaho\u27s and Objectors\u27 Response to Summary Judgment Motio

CDAT\u27s Response to Idaho, Hecla, and NIWRG

The Coeur d\u27Alene Tribe\u27s Response to the State of Idaho, Hecla, and the North Idaho Water Rights Group

CDAT\u27s Response to Idaho, Hecla, and NIWRG

The Coeur d\u27Alene Tribe\u27s Response to the State of Idaho, Hecla, and the North Idaho Water Rights Group

CDAT\u27s Response to Idaho, Hecla, and NIWRG

The Coeur d\u27Alene Tribe\u27s Response to the State of Idaho, Hecla, and the North Idaho Water Rights Group