Primary investigation into the occurrence of Hydroxymethylfurfural (HMF) in a range of smoked products

5-hydroxymethylfurfural (HMF) is produced in foods through many different pathways. Recently, studies have revealed its potential mutagenic and carcinogenic properties. Determination of HMF was originally used as an indicator of both the extent of thermal processing a food had undergone and food quality. It has been identified in a variety of food products such as bread, breakfast cereals, fruit juices, milk and honey. In addition to the thermal processes that lead to the formation of HMF during thermal treatment, food smoking also creates conditions that result in the formation of HMF. This can take place within the food due to the elevated temperatures associated with hot smoking, or by the proximity of the products of the pyrolysis of the wood matrix that is used for smoking (cold smoking). This may lead to further contamination of the product by HMF over and above that associated with the rest of the preparation process. Until now, there have been no studies examining the relation between the smoking procedure and HMF contamination in smoked food. This study is a primary investigation measuring HMF levels in three categories of smoked food products; cheese, processed meat, and fish using HPLC-UV. The amount of HMF found in all three product categories supports our hypothesis that HMF levels are due to both internal pathways during processing and external contamination from smoke generation matrix (wood) employed. The results ranged from 1 ppb (Metsovone traditional Greek smoked cheese) to 4ppm (Hot-smoked ready to eat mackerel). Subsequently for smoked cheese products, a correlation was found between HMF and phenolic compounds generated by the smoking procedures and identified by SPME-GCMS. It was observed that cheese samples that had higher concentrations of HMF were also found to have higher concentrations of syringol and cresols. It is important therefore to understand the smoking procedure’s effect on HMF formation. This will aid in the development of mitigation strategies to reduce HMF formation while retaining the flavour of the smoked products

Design of Polymer Extrusion Dies Using Finite Element Analysis

A computational fluid dynamics (CFD) model has been developed to compute the pressure, temperature, velocity, viscosity and viscous dissipation in the high-density polyethylene (HDPE) extrusion process. The numerical approach agrees fairly well with the experimental data recorded during the extrusion process of the material. The extrusion spider die was designed to produce high-density polyethylene pipes of 32 mm inner nominal diameter and 2.4 mm thickness. In order to investigate if the spider legs are able to perform under the pressure occurred using the maximum flow rate provided by the single screw extruder of this study, a stress analysis was conducted on a single spider leg. This fluid-structure interaction (FSI) problem was solved using the COMSOL Multiphysics software. Finally, the results obtained from the FE analysis were applied in the design and fabrication of the spider die, selecting IMPAX (tool steel) as fabrication material

Artificial Neural Networks and Their Applications in the Engineering of Fabrics

WOS: 00036372550000

A high-order Nystrom discretization scheme for boundary integral equations defined on rotationally symmetric surfaces

A scheme for rapidly and accurately computing solutions to boundary integral equations (BIEs) on rotationally symmetric surfaces in R^3 is presented. The scheme uses the Fourier transform to reduce the original BIE defined on a surface to a sequence of BIEs defined on a generating curve for the surface. It can handle loads that are not necessarily rotationally symmetric. Nystrom discretization is used to discretize the BIEs on the generating curve. The quadrature is a high-order Gaussian rule that is modified near the diagonal to retain high-order accuracy for singular kernels. The reduction in dimensionality, along with the use of high-order accurate quadratures, leads to small linear systems that can be inverted directly via, e.g., Gaussian elimination. This makes the scheme particularly fast in environments involving multiple right hand sides. It is demonstrated that for BIEs associated with the Laplace and Helmholtz equations, the kernel in the reduced equations can be evaluated very rapidly by exploiting recursion relations for Legendre functions. Numerical examples illustrate the performance of the scheme; in particular, it is demonstrated that for a BIE associated with Laplace's equation on a surface discretized using 320,800 points, the set-up phase of the algorithm takes 1 minute on a standard laptop, and then solves can be executed in 0.5 seconds.Comment: arXiv admin note: substantial text overlap with arXiv:1012.56301002.200

Large Diameter Femoral Heads Impose Significant Alterations on the Strains Developed on Femoral Component and Bone: A Finite Element Analysis

Total Hip Arthroplasty aims at fully recreating a functional hip joint. Over the past years modular implant systems have become common practice and are widely used, due to the surgical options they provide. In addition Big Femoral Heads have also been implemented in the process, providing more flexibility for the surgeon. The current study aims at investigating the effects that femoral heads of bigger diameter may impose on the mechanical behavior of the bone-implant assembly. Using data acquired by Computed Tomographies and a Coordinate Measurement Machine, a cadaveric femur and a Profemur-E modular stem were fully digitized, leading to a three dimensional finite element model in ANSYS Workbench. Strains and stresses were then calculated, focusing on areas of clinical interest, based on Gruen zones: the calcar and the corresponding below the greater trochanter area in the proximal femur, the stem tip region and a profile line along linea aspera. The performed finite elements analysis revealed that the use of large diameter heads produces significant changes in strain development within the bone volume, especially in the lateral side. The application of Frost’s law in bone remodeling, validated the hypothesis that for all diameters normal bone growth occurs. However, in the calcar area lower strain values were recorded, when comparing with the reference model featuring a 28mm femoral head. Along line aspera and for the stem tip area, higher values were recorded. Finally, stresses calculated on the modular neck revealed increased values, but without reaching the yield strength of the titanium alloy used

Multi-parameter analysis of curing cycle for GNPs/glass fabric/ epoxy laminated nanocomposites

In this study, a multi-parameter analysis, using Taguchi method for design of experiments, has been conducted to investigate the optimum curing conditions for GNPs/E-glass fabric/epoxy laminated nanocomposites. The independent variables in the L25 Taguchi orthogonal array were heating rate, curing temperature and curing time, addressing five levels each. Tensile and 3-point bending tests were performed for each experiment number (run number) of the Taguchi L25. The analysis shown that the most significant para­meter for tensile strength is the time and for flexural strength is the tem­pe­ra­ture. Also, it shown that the optimum performance was obtained for tem­pera­ture values greater than the glass transition temperature Tg

Mesh management methods in finite element simulations of orthodontic tooth movement

In finite element simulations of orthodontic tooth movement, one of the challenges is to represent long term tooth movement. Large deformation of the periodontal ligament and large tooth displacement due to bone remodelling lead to large distortions of the finite element mesh when a Lagrangian formalism is used. We propose in this work to use an Arbitrary Lagrangian Eulerian (ALE) formalism to delay remeshing operations. A large tooth displacement is obtained including effect of remodelling without the need of remeshing steps but keeping a good-quality mesh. Very large deformations in soft tissues such as the periodontal ligament is obtained using a combination of the ALE formalism used continuously and a remeshing algorithm used when needed. This work demonstrates that the ALE formalism is a very efficient way to delay remeshing operations