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Experimental tests on slip factor in friction joints: Comparison between european and American standards
Friction joints are used in steel structures submitted to cyclic loading such as, for example, in steel and composite bridges, in overhead cranes, and in equipment subjected to fatigue. Slip-critical steel joints with preloaded bolts are characterized by high rigidity and good performance against fatigue and vibrational phenomena. The most important parameter for the calculation of the bolt number in a friction connection is the slip factor, depending on the treatment of the plane surfaces inside the joint package. The paper focuses on the slip factor values reported in European and North American Specifications, and in literature references. The differences in experimental methods of slip test and evaluation of them for the mentioned standards are discussed. The results from laboratory tests regarding the assessment of the slip factor related to only sandblasted and sandblasted and coated surfaces are reported. Experimental data are compared with other results from the literature review to find the most influent parameters that control the slip factor in friction joint and differences between the slip tests procedure
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Batrachoseps attenuatus
Number of Pages: 6Integrative BiologyGeological Science
Design and analysis of bent functions using -subspaces
In this article, we provide the first systematic analysis of bent functions
on in the Maiorana-McFarland class
regarding the origin and cardinality of their -subspaces, i.e.,
vector subspaces on which the second-order derivatives of vanish. By
imposing restrictions on permutations of , we specify
the conditions, such that Maiorana-McFarland bent functions admit a unique -subspace of dimension . On the
other hand, we show that permutations with linear structures give rise to
Maiorana-McFarland bent functions that do not have this property. In this way,
we contribute to the classification of Maiorana-McFarland bent functions, since
the number of -subspaces is invariant under equivalence.
Additionally, we give several generic methods of specifying permutations
so that admits a unique -subspace. Most
notably, using the knowledge about -subspaces, we show that using
the bent 4-concatenation of four suitably chosen Maiorana-McFarland bent
functions, one can in a generic manner generate bent functions on
outside the completed Maiorana-McFarland class
for any even . Remarkably, with our construction
methods it is possible to obtain inequivalent bent functions on
not stemming from two primary classes, the partial spread
class and . In this way, we contribute to a better
understanding of the origin of bent functions in eight variables, since only a
small fraction, of which size is about , stems from and
, whereas the total number of bent functions on
is approximately
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