Set-Valued Means of Random Particles

Planar images of powder particles or sand grains can be interpreted as figures, i.e., equivalence classes of directlycongruent compact sets. The paper introduces a concept of set-valuedmeans and real-valued variances for samples of such figures. Inobtaining these results, the images are registered to have similarlocations and orientations. The method is applied to find a mean figure of a sample of polygonal particles.     

Phase Characterization of Precipitated Zirconia

The phase compositions of undoped and europium-doped zirconia samples, obtained by precipitation and thermal treatment from 350° to 1000°C, have been investigated by powder X-ray diffractometry, infrared spectroscopy, and cathodoluminescence spectroscopy. The low-temperature stabilization of tetragonal zirconia is mainly controlled by the presence of anion additives, such as ammonium chloride. The influence of the crystallite size is less important. Cathodoluminescence spectra show a structural similarity between tetragonal and amorphous zirconia.     

Stereological determination of curvature distributions of spatial fibre systems

Under the assumption of homogeneity and isotropy, this paper solves the problem of determining spatial curvature distributions of fibre processes from curvatures of projection curves from thin sections. As an example, a sample of dislocation lines in a hot-rolled Fe-Ni alloy is discussed.     

Integration of analytical techniques in stochastic optimization of microsystem reliability

This paper presents an integrative application of several numerical analytical techniques and associated analysis tools for design optimization and damage prediction in electronics packages and microsystems. This design-for-reliability approach is based on four different types of numerical techniques that allow (1) high-fidelity modelling, (2) reduced order modelling, (3) numerical optimization and (4) uncertainty analysis. The capabilities and the characteristics of the methods that underpin these four types of modelling and analysis tools are firstly investigated. The integration of the methods and tools is then examined and a methodology for coupling the tools in an optimization process is proposed. This numerical methodology involves the following steps: (1) Define sampling points for the design of interest by design of experiments (DOE) and calculate the design response at each DOE point using high-fidelity analysis; (2) construct reduced order models (ROM) for fast analysis using the obtained response values at the DOE points; (3) Undertake deterministic optimization in the defined design space by ROM; and (4) Probabilistic optimization by including variation and uncertainty of the design in the optimization task. This approach is suitable to address design-for-reliability requirements at early design stages in a wide range of application areas. The application of this approach is demonstrated in a case for minimizing the thermal fatigue damage of flip-chip solder interconnects. Design modifications show that this approach can provide improved reliability of the package and in the same time satisfy a number of design requirements.     

Effect of Natural Antioxidants,Irradiation, and Cooking on Lipid Oxidation in Refrigerated,Salted Ground Beef Patties

Antioxidant effects of natural antioxidants in 73%‐lean ground beef patties during refrigeration were studied. Samples were subject to an antioxidant treatment (pomegranate extract, grape seed extract, butylated hydroxyanisole, or no treatment) and an irradiation treatment (0 or 1.5 kGy) before being evaluated for both uncooked and cooked indicators of lipid oxidation. Chemical evaluation of antioxidant activity were determined over 9 d through measurement of thiobarbituric reactive substances values. Physical evaluation of antioxidant activity was monitored by changes in physical color and sensory odor analysis on patties before and after cooking. Butylated hydroxyanisole extended the induction period of oxidation in all unirradiated beef patties better than the natural antioxidants. Panelists were able to distinguish a difference (in terms of oxidation attributes) between patty samples of different antioxidant and irradiation treatments while samples were uncooked, but unable to distinguish a difference between patties after cooking.     

Modelling methodology for thermal analysis of hot solder dip process

The shift of electronics industry towards the use of lead-free solders in components manufacturing brought also the challenge of addressing the problem of tin whiskers. Manufacturers of high reliability and safety critical equipment in sectors such as defence and aerospace rely increasingly on the use of commercial-of-the-shelf (COTS) electronic components for their products and systems. The use of COTS components with lead-free solder plated terminations comes with the risks for their long term reliability associated with tin whisker growth related failures. In the case of leaded type electronic components such as Quad Flat Package (QFP) and Small Outline Package (SOP), one of the promising solutions to this problem is to “re-finish” the package terminations by replacing the lead-free solder coatings on the leads with conventional tin–lead solder. This involves subjecting the electronic components to a post-manufacturing process known as Hot Solder Dip (HSD). One of the main concerns for adopting HSD (refinishing) as a strategy to the tin whisker problem is the potential risk for thermally induced damage in the components when subjected to this process.     

Error assessment for wind histories generated by autoregressive method

This study addresses possible obstacles and errors which can be expected when one applies the autoregressive method for simulation of wind histories. The mean value, variance, and power spectra of the wind speed of the generated sample are assessed by comparison with the target parameters required. The influence of the order of autoregression and of the number of sample points is investigated. A confidence interval probability is used as a measure of the accuracy of the simulation. Numerical results obtained from the example of the wind load on an antenna mast are provided.     

Solution to Control Problems for Parabolic Systems

The problems of control of parabolic systems in bounded space-time, bounded space, and bounded time domains are formulated, solved, and analyzed. State functions for such systems are controlled through external dynamic distributed perturbations and initial and boundary conditions. Conditions of accuracy and uniqueness of the solutions are analyzed.