Foot Morphometric Phenomena

Knowledge of the foot morphometry is important for proper foot structure and function. Foot structure as a vital part of human body is important for many reasons. The foot anthropometric and morphology phenomena are analyzed together with hidden biomechanical descriptors in order to fully characterize foot functionality. For Croatian student population the scatter data of the individual foot variables were interpolated by multivariate statistics. Foot morphometric descriptors are influenced by many factors, such as life style, climate, and things of great importance in human society. Dominant descriptors related to fit and comfort are determined by the use 3D foot shape and advanced foot biomechanics. Some practical recommendatios and conclusions for medical, sportswear and footwear practice are highlighted

Electrospinning: theoretical foundations and processing parameters

Elektropredenje je uspješni postupak pravljenja nanovlakana iz mlaza kapljevine u elektrostatičkome polju. Postavljene su teorijske osnove razumijevanja fizikalnoga mehanizma elektropredenja uz prognozu procesnih parametara. Tečenje i deformacija nabijenoga mlaza promatra se kroz izduženi 1D model. Za stacionarno je elektropredenje profil mlaza određen numerički. Analiza stabililnosti mlaza određena je aksijalno simetričnom perturbacijom. Dinamički model savijanja mlaza promatran je kroz numerički model za poli(etilen-oksid) PEO otopine. Primjer određivanja značajnijih optimalnih procesnih parametara pokazan je za funkciju cilja uz pomoć eksperimentalnih podataka. Navedene su i korisne radne karakteristike u prostoru određenom ovisnošću obujamnog protoka o električnome polju.Electrospinning is an efficient procedure for nanofibers fabrication from a liquid jet through a nozzle under the electrostatic field. A theoretical framework is established for the understanding of the physical mechanisms of electrospinning with parameter regimes prediction. A slender-body theory for stretched and charged jet was applied to this problem. For the steady electrospinning process, a jet profile was determined numericaly. A linear stability analysis of axisymmetric perturbation of the electric jet is presented. The dynamics model of the jet bending is derived and solved numerically for the PEO solution. The important electrospinning processing parameters are optimised using the response surface methodology based on experimental data. Useful operating diagrams in volume flux-electric field space are discussed

Blood Flow Multiscale Phenomena

The cardiovascular disease is one of most frequent cause deaths in modern society. The objective of this work is analyse the effect of dynamic vascular geometry (curvature, torsion,bifurcation) and pulsatile blood nature on secondary flow, wall shear stress and platelet deposition. The problem was examined as multi-scale physical phenomena using perturbation analysis and numerical modelling. The secondary flow determined as influence pulsatile pressure, vascular tube time-dependent bending and torsion on the main axial flow. Bifurcation and branching phenomena are analysed experimentally through, blood-like fluid pulsatile flow across elastic rubber-like Y-model model. The problem complex geometry near branching in platelet deposit modelling is resolved numerically as Falker-Skan flow

Foot Anthropometry and Morphology Phenomena

Foot structure description is important for many reasons. The foot anthropometric morphology phenomena are analyzed together with hidden biomechanical functionality in order to fully characterize foot structure and function. For younger Croatian population the scatter data of the individual foot variables were interpolated by multivariate statistics. Foot structure descriptors are influenced by many factors, as a style of life, race, climate, and things of the great importance in human society. Dominant descriptors are determined by principal component analysis. Some practical recommendation and conclusion for medical, sportswear and footwear practice are highlighted

The Cancellous Bone Multiscale Morphology-Elasticity Relationship

The cancellous bone effective properties relations are analysed on multiscale across two aspects; properties of representative volume element on micro scale and statistical measure of trabecular trajectory orientation on mesoscale. Anisotropy of the microstructure is described across fabric tensor measure with trajectory orientation tensor as bridging scale connection. The scatter measured data (elastic modulus, trajectory orientation, apparent density) from compression test are fitted by stochastic interpolation procedure. The engineering constants of the elasticity tensor are estimated by last square fitt procedure in multidimensional space by Nelder-Mead simplex. The multiaxial failure surface in strain space is constructed and interpolated by modified super-ellipsoid

Multiscale Phenomena Related to Diabetic Foot

Diabetes is a group of metabolic diseases causing a system disorder, i.e.; it cannot be explained or understood by phenomena on single material scale. The diabetic foot is studied as flexible multibody structure by nonlinear finite element method. The physical and geometrical multiscale heterogeneity is solved by multilevel finite element approach. The diabetic tissue is described by internal coordinate’s formalism, as complex multiscale process in tissue. The accompanying problem of the axisymetric wound healing is solved numerically. Some results related to foot deformity, stress and strain concentration and wound healing are presented

Design of dermal electrospun replacement

Background and Purpose: This study is related to the design of advanced dermal scaffolds (non-woven fibrous mats) to provide multifunctional properties. Materials and Methods: The nanofibre fabric from poly (ε-caprolactone) (PCL) solutions in acetone were produced by electrospinning. Based on SEM and its stochastic fibre characterization, equivalent fabric was generated by computer. Fibres network was created by random deposition of elastic straight segments within a representative volume element (RVE).Elastic and permeability properties determined experimentally and numerically. Results: The fibres diameter produced fibrous structure depends on solution concentration and electric field, what have been identified by surface response methodology. Effective Young’s modules for fibrous network measured and predicted by numerical model depend on fibres density and fibres diameter. Calculated data for permeability and pore distributionwere compared with models for fibrous media with acceptable error level. Conclusions: Effective elastic and permeability properties are determined by separate computational models. The scaffold multiscale behaviour is commented with multiphysic design procedure

Suitability of the rgb Channels for a Pixel Manipulation in a Spatial Domain Data Hiding Techniques

The aim of this research was to determine which channel in rgb color space is the most suitable (regarding perceptibility) for a pixel manipulation in a spatial domain data hiding techniques. For this purpose three custom test targets were generated. The research also shows the behavior of two closely related colors in the ps (Print-Scan) process. The results are interpreted using both a quantitative method (statistical comparison) and a qualitative method (visual comparison)