Automatic three-dimensional finite element mesh generation via modified ray casting

Three-dimensional (3-D) finite element mesh generation has been the target of automation due to the complexities associated with generating and visualizing the mesh. A fully automatic 3-D mesh generation method is developed. The method is capable of meshing CSG solid models. It is based on modifying the classical ray-casting technique to meet the requirements of mesh generation. The modifications include the utilization of the element size in the casting process, the utilization of 3-D space box enclosures, and the casting of ray segments (rays with finite length). The method begins by casting ray segments into the solid. Based on the intersections between the segments and the solid boundary, the solid is discretized into cells arranged in a structure. The cell structure stores neighbourhood relations between its cells. Each cell is meshed with valid finite elements. Mesh continuity between cells is achieved via the neighbourhood relations. The last step is to process the boundary elements to represent closely the boundary. The method has been tested and applied to a number of solid models. Sample examples are presented.     

Genetic approach to the minimization of the coupling between aircraft antennas

In this study, the optimization of the electromagnetic interference (EMI) induced by two aircraft onboard VHF–UHF transreceiver antennas is aimed. The EMI reduction is implemented by varying the antenna positions and orientations. The transreceiver antennas are modelled as single monopole antennas therefore the problem is reduced to antenna-to-antenna coupling optimization. The Method of Moments (MoM) is selected for the EMI analysis and the continuous parameter Genetic Algorithm (CPGA) is chosen for the optimization method. The results of the numerical analysis are verified by the measurement on a 1:10 scaled model in an anechoic chamber.     

Multi-functional floating-point MAF designs with dot product support

This paper presents multi-functional double-precision and quadruple-precision floating-point multiply-add fused (FPMAF) designs. The double-precision FPMAF design can execute adouble-precision floating-point multiply-add, or two single-precision floating-point multiplications, or a single-precision floating-point dot product. The quadruple-precision FPMAF can perform similar operations with quadruple, double and single precision operands. These architectures can perform a dot-product operation two times or more faster than a basic FPMAF design. The presented multi-functional designs are compared with basic double-precision and quadruple-precision FPMAF designs by ASIC syntheses. The syntheses results show that the proposed double-precision implementation has 8%more area than a standard double-precision FPMAF implementation, and the proposed quadruple-precision design has 12.5% more area than a standard quadruple-precision FPMAF. Both of the proposed designs have one more pipeline stage compared to the basic designs.     

Generic Method of Preparing Multifunctional Fluorescent Nanoparticles Using Flash NanoPrecipitation

There is increased demand for nanoparticles with a high fluorescence yield that have the desired excitation wavelength, surface functionalization, and particle size to act as biological probes. Here, a simple, rapid, and robust method, Flash NanoPrecipitation (FNP), to produce such fluorescent nanoparticles is described. This process involves encapsulation of a hydrophobic fluorophore with an amphiphilic biocompatible diblock copolymer in a kinetically frozen state. FNP is used to produce nanoparticles ranging from 30 to 800 nm with fluorescence emission peaks ranging from, but not limited to, 370 nm to 720 nm. Such fluorescent nanoparticles remain stable in aqueous solutions, and, in contrast to soluble dyes, show no photobleaching. Fluorophores and drugs are incorporated into a single nanoparticle, allowing for simultaneous drug delivery and biological imaging. In addition, functionalization of nanoparticle surfaces with disease‐specific ligands permits precise cell targeting. These features make FNP‐produced fluorescent nanoparticles highly desirable for various biological applications.     

UTILIZATION OF OPIUM POPPY WASTES AS A FUEL SOURCE

Air dried and ground opium poppy stalks suspended in water containing sodium carbonate catalysts have been completely converted into liquid fuels and water-solubles chemicals at 573 °K in a 0.1 liter autoclave. Extractives and oil properties obtained from stalks and poppy seed were studied. Major compenents of the oil were linoleic acid (60.2 %) and oleic acid (22.3 %). Alcohol-benzene extractives of the stalks were 28.8 % while ether solubility was 7.5 %.     

Particulate Dry Deposition and Overall Deposition Velocities of Polycyclic Aromatic Hydrocarbons

Previous studies have shown that the dry deposition of semivolatile organic compounds to the Great Lakes can account for a significant fraction of their total inputs. However, there is no generally accepted method to directly measure dry deposition. In this study the particulate dry deposition of polycyclic aromatic hydrocarbons (PAHs) was measured using smooth surrogate surfaces during the winter of 1996–1997 in Chicago. Concurrently, ambient air samples were collected. Average particulate Σ13-PAH fluxes and ambient concentrations were 120±28?μg/m2?d and 30±16?ng/m3, respectively. The measured particulate dry deposition fluxes were similar to those measured in other urban areas. Overall dry deposition velocities of PAHs calculated using the dry deposition fluxes and ambient concentrations averaged 4.5±3.1?cm/s. This value is higher than values typically used to estimate PAH particulate deposition, however, it agrees well with values determined using similar techniques. The overall dry deposition velocity for individual PAHs generally decreased with increasing molecular weight. This finding is consistent with the previous experimental studies that have shown that a greater fraction of the higher molecular weight PAHs are associated with fine particles relative to the lower molecular weight compounds.