Dry vs. wet testing: quasi-static tensile experiment setup for polymer based biomaterials

Polymer materials can be manufactured with high reproducibility and do offer the potential for chemical modification. This enables matrix property modification and fine-tuning of several material characteristics, such as tissue-implant interaction, inflammatory potential or susceptibility to biofilm formation. Whereas manufacturing protocols are crucial for the resulting material properties, also the evaluation in terms of performance and safety has to be considered. Regarding this, both, temperature and composition of test medium may affect the physicochemical properties of implant materials. The present study addresses the influence of test medium compared to dry test conditions, each at two different temperatures, on the mechanical properties of elastomeric film and nonwoven materials.

Color contamination matrix property assessment for improvement of colored smoke PIV

A single-camera color PIV system that can acquire PIV data of three separated layers has been redesigned, purposing improvement of wind tunnel applicability. We target smoke image that has particle-per-pixel values higher than unity. The system constitutes of a high-power color-coding illuminator and a digital color high-speed video camera. RGB values in recorded image involves severe color contaminations due to five optical and digital sequences (Fig. 1). To quantify this, a snapshot calibration is proposed to describe the contamination matrix equation (Eq. (1)). Taking the inverse matrix (Eq. (2)) allows in-plane PIV in each color layer to be accurately implemented. We also derive mathematical limits to operate the colored smoke PIV, which is explained by the matrix property (Eq (3)). Feasibility of the proposed method has been demonstrated by application to a turbulent wake behind a Delta wing (Fig. 2) and also to a boundary layer flow along heated chocolate.

Algebraic multigrid for the finite pointset method

We investigate algebraic multigrid (AMG) methods for the linear systems arising from the discretization of Navier–Stokes equations via the finite pointset method. In the segregated approach, three pressure systems and one velocity system need to be solved. In the coupled approach, one of the pressure systems is coupled with the velocity system, leading to a coupled velocity-pressure saddle point system. The discretization of the differential operators used in FPM leads to non-symmetric matrices that do not have the M-matrix property. Even though the theoretical framework for many AMG methods requires these properties, our AMG methods can be successfully applied to these matrices and show a robust and scalable convergence when compared to a BiCGStab(2) solver.

Run length limited error control codes construction based on one control matrix property

In this manuscript a simple method is presented for constructing run length limited error control codes from linear binary block codes. The run length limited properties are obtained via addition of a carefully chosen fixed binary vector - a modifier to all codewords without introducing any additional redundancy. Modifier selection is based on a specific property, which can be found in some of the linear binary block codes control matrices. Similar known methods are based on properties of generator matrices. However some codes are specified via control matrices, for example low density parity check codes. The method proposed in this letter could be applied to some of them directly. This is illustrated in this manuscript using example in which a run length limited low density parity check code is obtained from Gallager code.

Szeged Matrix Property Indices as Descriptors to Characterize Fullerenes

Fullerenes are class of allotropes of carbon organized as closed cages or tubes of carbon atoms. The fullerenes with small number of atoms were not frequently investigated. This paper presents a detailed treatment of total strain energy as function of structural feature extracted from isomers of C40 fullerene using Szeged Matrix Property Indices (SMPI). The paper has a two-fold structure. First, the total strain energy of C40 fullerene isomers (40 structures) was linked with SMPI descriptors under two scenarios, one which incorporate just the SMPI descriptors and the other one which contains also five calculated properties (dipole moment, scf-binding-energy, scf-core-energy, scf-electronic-energy, and heat of formation). Second, the performing models identified on C40 fullerene family or the descriptors of these models were used to predict the total strain energy on C42 fullerene isomers. The obtained results show that the inclusion of properties in the pool of descriptors led to the reduction of accurate linear models. One property, namely scf-binding-energy proved a significant contribution to total strain energy of C40 fullerene isomers. However, the top-three most performing models contain just SMPI descriptors. A model with four descriptors proved most accurate model and show fair abilities in prediction of the same property on C42 fullerene isomers when the approach considered the descriptors identified on C40 as the predicting descriptors for C42 fullerene isomers.