Confinement induced instability of thin elastic film

A confined incompressible elastic film does not deform uniformly when subjected to adhesive interfacial stresses but with undulations which have a characteristic wavelength scaling linearly with the thickness of the film. In the classical peel geometry, undulations appear along the contact line below a critical film thickness or below a critical curvature of the plate. Perturbation analysis of the stress equilibrium equations shows that for a critically confined film the total excess energy indeed attains a minima for a finite amplitude of the perturbations which grow with further increase in the confinement.Comment: 11 pages, 6 figure

Creep and creep rupture of laminated graphite/epoxy composites

An incremental numerical procedure based on lamination theory is developed to predict creep and creep rupture of general laminates. Existing unidirectional creep compliance and delayed failure data is used to develop analytical models for lamina response. The compliance model is based on a procedure proposed by Findley which incorporates the power law for creep into a nonlinear constitutive relationship. The matrix octahedral shear stress is assumed to control the stress interaction effect. A modified superposition principle is used to account for the varying stress level effect on the creep strain. The lamina failure model is based on a modification of the Tsai-Hill theory which includes the time dependent creep rupture strength. A linear cumulative damage law is used to monitor the remaining lifetime in each ply

Fundamentals of Flakeboard Manufacture: Viscoelastic Behavior of the Wood Component

Theories of the viscoelastic behavior of amorphous polymers are reviewed and are used to describe the density gradient formation in flakeboard. This technique utilizes measured temperature and gas pressure at discrete locations inside a flake mat during hot pressing to predict the glass transition temperature of wood as a function of press time. The difference between the flake temperature and the predicted glass transition temperature is a relative indicator of the amount of flake deformation and stress relaxation at a location in the mat. A knowledge of the stress history imposed in the mat is then used to relate flake deformation and stress relaxation to the formation of a density gradient. This analysis allows for a significant portion of the density gradient to develop after the hot press has closed. Experimental data for various density gradients support the theories presented here

A splice site variant in INPP5E causes diffuse cystic renal dysplasia and hepatic fibrosis in dogs

Ciliopathies presenting as inherited hepatorenal fibrocystic disorders are rare in humans and in dogs. We describe here a novel lethal ciliopathy in Norwich Terrier puppies that was diagnosed at necropsy and characterized as diffuse cystic renal disease and hepatic fibrosis. The histopathological findings were typical for cystic renal dysplasia in which the cysts were located in the straight portion of the proximal tubule, and thin descending and ascending limbs of Henle's loop. The pedigree of the affected puppies was suggestive of an autosomal recessive inheritance and therefore, whole exome sequencing and homozygosity mapping were used for identification of the causative variant. The analyses revealed a case-specific homozygous splice donor site variant in a cilia related gene, INPP5E: c.1572+5G>A. Association of the variant with the defect was validated in a large cohort of Norwich Terriers with 3 cases and 480 controls, the carrier frequency being 6%. We observed that the identified variant introduces a novel splice site in INPP5E causing a frameshift and formation of a premature stop codon. In conclusion, our results suggest that the INPP5E: c.1572+5G>A variant is causal for the ciliopathy in Norwich Terriers. Therefore, genetic testing can be carried out in the future for the eradication of the disease from the breed

4-(8-Eth­oxy-2,3-dihydro-1H-cyclo­penta­[c]quinolin-4-yl)butane-1-peroxol

In the title mol­ecule, C18H23NO3, the hydro­per­oxy­butyl substituent is nearly fully extended, with the four torsion angles in the range 170.23 (10)–178.71 (9)°. The O—O distance in the hydro­peroxide group is 1.4690 (13) Å. This group acts as an inter­molecular hydrogen-bond donor to a quinoline N atom. This results in dimeric units about the respective inversion centers, with graph-set notation R 2 2(18)

Mixed-Mode I + II fracture characterization of bonded joints using a novel Multi-Mode Apparatus

The present work presents the experimental test results to assess the toughness of an adhesive joint, using a previouslydefined crack equivalent data reduction scheme applied to a new multi-mode apparatus, inspired in a load jig previouslydeveloped by Fernlund and Spelt. The patented jig allows for easy alteration of the mode-mixity and permits coveringthe full range of mixed-mode I+II combinations. A data reduction scheme based on specimen compliance, beam theoryand crack equivalent concept is used to overcome several difficulties inherent to the test analysis. The method assumesthat the performed test can be viewed as a combination of the double cantilever beam and asymmetrically loaded endnotchedflexure tests, which provide modes I and II fracture characterization, respectively. A numerical analysisincluding a cohesive mixed-mode I+II damage model was performed considering different mixed-mode loadingconditions to validate the proposed data reduction scheme. Issues regarding self-similar crack growth and fractureprocess zone development are discussed. It was verified that the considered in-plane mix mode fracture criterion is wellcaptured using the proposed data reduction scheme