Pool Boiling of Water–Al2O3 and Water–Cu Nanofluids Outside Porous Coated Tubes

This paper deals with pool boiling of water–Al₂O₃ and water–Cu nanofluids on porous coated, horizontal tubes. Commercially available stainless-steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate a test heater. Aluminum porous coatings 0.15 mm thick with porosity of about 40% were produced by plasma spraying. A smooth tube served as a reference tube. The experiments were conducted under different absolute operating pressures of 200 kPa, 100 kPa, and 10 kPa. Nanoparticles were tested at concentrations of 0.01%, 0.1%, and 1% by weight. In all cases tested, enhancement heat transfer was always observed during boiling of water–Al₂O₃ and water–Cu nanofluids on smooth tubes compared to boiling of distilled water. Contrary to smooth tubes, addition of even a small amount of nanoparticles resulted in deterioration of heat transfer during pool boiling of water–Al₂O₃ and water–Cu nanofluids on porous coated tubes in comparison with boiling of distilled water.     

Thermoelastic Deformations of Cylindrical Multi-Layered Shells Using a Direct Approach

In this article we study the deformation of thermo-elastic multi-layered shells, using a Cosserat model. By this direct approach, the shell-like bodies are modeled as deformable surfaces with a triad of rigidly rotating directors assigned to every point. The thermal effects are described with the help of two independent temperature fields. Concerning cylindrical orthotropic layered shells, we establish a general solution procedure for a class of thermal stresses problems. These analytical solutions are compared in some special cases with the corresponding three-dimensional solutions and thus, the thermo-elastic coupling coefficients for shells are identified in terms of the material/geometrical parameters of the layers. Finally, we present a comparison between our theoretical results and the numerical solutions obtained by a finite element analysis of a 3-layered cylindrical shell.     

Chicken muscle homogenate gelation properties: effect of pH and muscle fiber type

Gelation properties of chicken breast and thigh muscle homogenates at a protein concentration of 4.5% under different pH conditions (5.80–6.60) and those of myofibrillar proteins at a protein concentration of 2% were compared to determine the influence of muscle fibre types on gelation. The optimal gelling pH for breast muscle homogenates (pH 6.30) was slightly higher than that for thigh muscle homogenates (pH 5.80–6.30), a similar trend was found for the isolated chicken myofibrillar proteins (pH 6.00 for breast and 5.50 for leg). Similarly, the pH values at which breast muscle homogenate gels were weaker (pH<6.20) or stronger (pH6.20) than thigh muscle homogenate gels were higher when compared with chicken breast and leg myofibrillar protein gels (pH<5.80 and pH>5.90, respectively).     

A comparison of selected quality features of the tissue and slaughter yield of wild and cultivated pikeperch<Emphasis Type="Italic"> Sander lucioperca</Emphasis> (L.)

The study focused on the comparison of carcass and fillet yields, fillet color, the content of basic components, and the fatty acid composition of tissue from cultivated and wild pikeperch. There was no variation in yield between carcasses and fillets. The brightness and redness of the color of the fillet surfaces of both types of fish were comparable, although the yellowness, chromaticity and shade of color differed. The tissue of cultivated fish had three times more fat (2.87%) than did that of wild fish; the difference was compensated for by water content. The protein and mineral component contents did not vary significantly. The total levels of saturated and monounsaturated acids in the tissue lipids in 1 g of fat varied. No differences were observed between the total amount of polyunsaturated fatty acids (PUFA), PUFAn-3, PUFAn-6, or in the n-3/n-6 proportion. One consequence of the higher fat content in cultivated pikeperch tissue was that the contents of eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic (DHA; 22:6n-3) acids per 100 g of fillet were significantly higher than in the tissue of wild pikeperch.     

Application of computer vision systems for estimation of fat content in poultry meat

The paper presents the possibility of use a computer vision system (CVS) for estimation fat content in poultry meat. The estimation of this ingredient content was made in the material obtained in industrial conditions. Chicken and turkey carcasses were selected randomly, from which the thigh muscles (from chickens and turkeys) and chicken breast muscles were taken. Analysis of correlation was made between content of white spots achieved with CVS method and fat content determined using the reference Soxhlet method. According to the achieved results, it was concluded that the computer vision system for images of turkey thigh muscles can be used to estimate its fat content.     

Measurement of mechanical properties in a 316L stainless steel welded joint

The aim of this study was to measure the mechanical properties of weld material taken from a single weld bead laid down on a 316L steel plate. Due to the low available volume of weld material, microsamples with a total length of 5.5 mm were used. The Digital Image Correlation method (DIC), which enables measurement of mechanical properties of very small samples, was employed for the strain measurements in a uniaxial tensile test. Samples were cut out from three different zones of the specimen: plate, weld, and the heat affected zone. The material from heat affected zone showed the highest value of the Ultimate Tensile Strength (UTS) (580 ± 7 MPa) and yield strength (339 ± 6 MPa). Plate material had lower UTS (559 ± 5 MPa) and yield strength (304 ± 7 MPa). The lowest values of UTS (526 ± 6 MPa) and yield strength (291 ± 8 MPa) have been revealed for the weld. The values obtained for UTS, yield strength and elongation to failure for the plate material were compared with data obtained using standard test specimens. No significant differences between results obtained for the microsamples and standard samples have been found.     

Evaluation of the mechanical behavior of W7-X central support connections by means of semi-automated FE analysis

The stellarator Wendelstein 7-X is under construction at the Max-Planck-Institut für Plasmaphysik in Greifswald. Its superconducting coil system is fixed by a massive structure. During machine operation the coils exert high forces and moments against each other and the central support structure (CSS). Therefore, the detailed analysis of the coil to CSS connections, the so-called central support elements (CSE), is a critical item. The major details of the design have been frozen; nevertheless, there is still need for detailed analysis of the CSEs due to assembly issues, and later on for exploring operational limits of the machine. These analyses have to be performed quickly, reliably, and shall provide results in a standardized form to enable timely responses to the assembly team. Special numerical tools – finite element (FE) parametric models of CSEs – have been developed for the purpose of such analyses. In the models, the geometry, material properties, contact conditions, loads as well as results presentation are defined in a parametric way. The use of the developed models for the definition of the final weld parameters, bolt preloads, assessment of acceptable tolerances, and optimal positions of the CSE-wedges before welding is also discussed.     

Raspberry seed extract effect on the ferroxidase activity of ceruloplasmin isolated from plasma

In this study, the effect of the raspberry seed extract (RSE) on the ferroxidase activity of ceruloplasmin (Cp) isolated from healthy male subject serum was analyzed. The ferroxidase activity of Cp was determined by spectrophotometry using Fe(II) – histidine complex and ferrozine as a chromogenic reagent. The ferroxidase activity of ceruloplasmin was demonstrated in dose-dependent way within the range 22–66 μg/ml. The effect of RSE on Fe(II) concentration, measured as the decrease of Fe(II) concentration in samples and expressed as ΔFe(II), was found to be a dose-dependent within the range 1.20–51.56 μg dm/ml. The ferroxidase activity of Cp was influenced by the RSE within its studied range. However, the addition of the highest concentration of RSE (51.56 μg dm/ml) to the sample containing the highest level of Cp (66 μg/ml) did not affect its ferroxidase activity. It may be suggested that the competition for Fe(II) as the substrate limits the effect of RSE on Cp activity and causes no further changes in Fe(II) elimination.     

Bioinspired Computational Framework for Enhancing Creativity, Optimality, and Robustness in Design

This paper presents results of transdisciplinary research on the development of a bioinspired computational framework for engineering design. This framework is intended to support design by addressing three critical design objectives, including novelty, optimality, and robustness. It provides several computational models and methods, which are inspired by fundamental processes occurring in nature, and discusses their potential for enhancing design. They include models and methods for evolutionary, developmental, and coevolutionary design. Their use is illustrated with examples from the area of steel structural design ranging from a simple cantilever beam design problem to a much more complex problem of designing wind bracings in tall buildings. The paper also shows how several methods and models can be integrated and form a coherent bioinspired computational framework for engineering design.     

Microstructural stability and creep properties of die casting Mg–4Al–4RE magnesium alloy

The AE44 (Mg–4Al–4RE) alloy was prepared by a hot-chamber die casting method. The microstructure, microstructural stability and creep properties at 175 °C were investigated. The microstructure was analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and the Rietveld method. The results show that die cast AE44 magnesium alloy consists of α-Mg, Al₁₁RE₃, Al₂RE and Al_2.12RE_0.88 phases. The Al₁₁RE₃ phase is thermally stable at 175 °C whereas the metastable Al_2.12RE_0.88 phase undergoes a transition into the equilibrium Al₂RE phase. The alloy investigated is characterized by good creep properties at temperatures of 175 °C and 200 °C.