Efficiency and accuracy of fluid-structure interaction simulations using an implicit partitioned approach

An implicit partitioned arbitrary Lagrangian– Eulerian approach for fluid-structure interaction computations is considered. Enhancements of the coupled solution procedure by nonlinear multigrid techniques, an adaptive underrelaxation, and proper grid movement techniques are investigated.     

Smart doorplate

This paper introduces the vision of smart doorplates within an office building. The doorplates are able to display current situational information about the office owner, to act instead of the office owner in case of absence, and to direct visitors to the current location of the office owner based on a location-tracking system. Different scenarios are proposed and a prototype implementation is presented.     

Influence of Processing Temperature on Microcellular Injection‐Moulded Wood–Polypropylene Composites

Summary: Microcellular wood fibre reinforced polymer materials are significant because of their possibility to reduce the density of automotive components through microcellular structure, process and product part advantages, and as a new development with bio‐fibre strengthened plastics. Soft wood fibre reinforced PP composites in box part and panel shape were prepared by an injection moulding process. Polymeric microspheres as a chemical foaming agent (endothermic) were used to produce the microcellular composites. The influence of injection moulding processing temperature on the microcellular structure and properties (tensile and flexural properties, notched charpy impact strength) was investigated by varying the temperature over the 150–170 °C, 160–180 °C and 170–190 °C. A comparative study of cell morphology, weight reduction and mechanical properties was conducted between box part and panel. Microcell morphology, cell size, shape and distribution were investigated using scanning electron micrographs. The results indicated that the lower processing temperature should be below the range of 170–190 °C and processing temperature at 160–180 °C, where the composites showed finer cellular structure compared to other processing temperatures. The mechanical properties did not differ with the variation of processing temperature regardless of composite types (box part or panel). Cellular structure changes in the box part were found considering near or far from injecting point.

Microcellular injection‐moulded box part (geometry: 150 × 100 × 70 mm³ in size) of soft wood fibre–PP composites.     

Design, development and testing of a turning dynamometer for cutting force measurement

In this study, a turning dynamometer that can measure static and dynamic cutting forces by using strain gauge and piezo-electric accelerometer, respectively, has been designed and developed. The orientation of octagonal rings and strain gauge locations has been determined to maximize sensitivity and to minimize cross-sensitivity. The developed dynamometer is connected to a data acquisition system. Cutting force signals were captured and transformed into numerical form and processed using a data acquisition system consisting of necessary hardware and software running on MS-Windows based personal computer. The obtained results of machining tests performed at different cutting parameters showed that the dynamometer could be used reliably to measure cutting forces. Although the dynamometer was developed primarily for turning operations, it can be used to measure cutting forces during nearly all machining operations (milling, drilling, etc.).     

Learning Sequences of Compatible Actions Among Agents

Action coordination in multiagent systemsis a difficult task especially in dynamicenvironments. If the environment possessescooperation, least communication,incompatibility and local informationconstraints, the task becomes even moredifficult. Learning compatible action sequencesto achieve a designated goal under theseconstraints is studied in this work. Two newmultiagent learning algorithms called QACE andNoCommQACE are developed. To improve theperformance of the QACE and NoCommQACEalgorithms four heuristics, stateiteration, means-ends analysis, decreasing reward and do-nothing, aredeveloped. The proposed algorithms are testedon the blocks world domain and the performanceresults are reported.     

Calculation of extrapolation distances by low order Chebyshev polynomial approximation of transport equation in slab geometry

In this study, the problem of extrapolated end point has been studied in one-speed neutron transport equation with isotropic scattering by using the Chebyshev polynomial approximation which is called T_N method. Assuming neutrons of one speed, extrapolated end point are calculated for the uniform finite slab using Mark and Marshak type vacuum boundary conditions. It is shown that low order T_N method gives very good results of low order spherical harmonics approximation and diffusion theory for extrapolation of the flux of neutrons leaking from the medium. We present an alternative method which is similar to P₁ method to calculate the extrapolation distances z₀. Moreover, we prefer new solution of transport equation in one-dimensional slab geometry.     

Cr(VI) reduction in aqueous solutions by siderite

Hexavalent chromium is a common and toxic pollutant in soils and wastewaters. Reduction of the mobile Cr(VI) to less mobile and less toxic Cr(III) is a solution for decontamination of industrial effluents. In this study, the reduction of hexavalent chromium in aqueous solutions by siderite was investigated. The influences of amount of acid, contact time, siderite dosage, initial Cr(VI) concentration, temperature and particle size of siderite have been tested in batch runs. The process was found to be acid, temperature and concentration dependent. The amount of acid is the most effective parameter affecting the Cr(VI) reduction since carbonaceous gangue minerals consume acid by side reactions. The highest Cr(VI) reduction efficiency (100%) occurred in the 50 mg/l Cr(VI) solution containing two times acid with respect to stoichiometric amount of Cr(VI) and at the conditions of siderite dosage 20 g/l, contact time 120 min and temperature 25 degrees C. Reduction efficiency increased with increase in temperature and decrease in particle size. The reduction capacity of siderite was found to be 17 mg-Cr(VI)/g.     

Commercial test kits and the determination of histamine in traditional (ethnic) fish products-evaluation against an EU accepted HPLC method

Although commercial test kits are generally used and/or evaluated for determining histamine in fresh and canned fish, and fish meal, there is little information on their performance and the application for traditional fish products (TFPs), which generally differ in product properties. In this study, three quantitative (Food EIA, Veratox, Histaquant) and four qualitative (Histasure, Histameter, Transia qualitative and semi-quantitative) commercial histamine test kits were evaluated against HPLC method for detecting histamine in several traditional fish products. Among the quantitative kits, Histamine Food EIA showed the best correlation with HPLC method for TFPs (R² = 0.9132) as well as good recoveries ranging between 89 (±4.11)% and 117 (±1.50)%. Although good recoveries were also observed with Veratox kit, poor correlation was found with HPLC. Poor correlation and low recoveries were also observed with Histaquant. Histasure and Transia tube histamine kits showed good agreement with HPLC results. However, the detection limit for Transia qualitative kit is 100 ppm, and for Histasure and Transia semi-quantitative kits can be set to 50 ppm. Therefore, Histasure and Transia semi-quantitative kits are found more suitable for either HACCP monitoring histamine in seafood processing plants or regulatory purposes according to Food Drug and Administration (FDA) legislation for TFPs. However, Transia semi-quantitative kit should be used in caution for histamine cut off values <50 ppm. This study shows that each test kit can represent different performance for determining histamine in TFPs according to product type, and therefore new commercial test kits should be evaluated against an approved analytical method before applications in future for these types of products.     

Elastoplastic contact/impact of rigidly supported composites

A general elastoplastic contact/impact model of a spherical object and a supported transversely isotropic composite layer or a half-space is presented. The main feature of the model is a contact law that is developed based on elastic–plastic and fully plastic indentation theory. For an impact event, the model parameters can easily be obtained analytically, computationally using finite elements (FE), and from experiments. The model results are compared to those from a nonlinear FE model developed in ABAQUS, and with limited experimental data showing excellent agreement. The model has also been tested for low-velocity impact, which compared very well with the FE results using ABAQUS/Explicit. The model is simple, yet it successfully captures a fairly complicated contact behavior.