A finite difference approach that employs an asymptotic boundarycondition on a rectangular outer boundary for modeling two-dimensionaltransmission line structures

The derivation of three asymptotic boundary conditions is presented. Techniques for implementing each of these on finite difference meshes with rectangular outer boundaries are discussed. Numerical results obtained using these boundary conditions in the finite difference analysis of both shielded and unshielded transmission lines are shown. The authors present detailed convergence studies on the use of each of these boundary conditions and discuss the memory requirements of each     

Development of a framework system for tool integration in a product information archive

The described framework system has the goal of providing an integration platform for engineering tools to interact. Engineering tools exchange information via the data repository of the framework system. In the European research project ESPRIT EP6896 Concurrent/Simultaneous Engineering System (CONSENS), a Product Information Archive (PIA) is being developed based on the object-oriented database system of the framework, the Object Management System. The Product model is based on a STEP compliant schema. This has been achieved by developing an Application Resource Model (ARM) for the required product information according to a user requirements analysis. The ARM then was mapped to the Integrated Resource Models of STEP which resulted in an object-oriented STEP compliant model. The main objective of PIA is the integration of the product information flows between parallel teams using the framework for product development. This is provided by an interface consisting of a library of functions that enable tools within and external to the framework to access PIA and exchange up-to-date product information. Additionally an X Motif based interface provides human users with direct access possibilities. The framework has been tested by the integration of various tools which support product development.     

Solutions to difficulties encountered in low-temperature SEM of some frozen hydrated specimens: Examination of Penicillium nalgiovense cultures

Penicillium nalgiovense cultures, which are used in the food industry, were found to be collapsed when prepared by standard procedures for scanning electron microscopy. Neither freeze-drying nor critical point-drying preserved the structure of cultures grown on agar media. Cryofixation and preparation of frozen hydrated samples using the Hexland Cryotrans CT 1000 attachment in conjunction with an AMR 1000A scanning electron microscope yielded micrographs of uncollapsed structures which could be used for morphological characterization. Several additional steps had to be used in sample preparation to achieve satisfactory results. Samples were held in a humid chamber prior to freezing; growth substrate was trimmed as thinly as possible (less than 1 mm above the support); the sides of samples were painted with a conductive cement to their upper edge; and frozen samples were coated intermittently with gold sputtered in several 2-min bursts.     

Fabrication and characterization of bit-patterned media beyond 1.5 Tbit/in2

We fabricated bit-patterned media (BPM) at densities as high as 3.3 Tbit/in(2) using a process consisting of high-resolution electron-beam lithography followed directly by magnetic film deposition. By avoiding pattern transfer processes such as etching and liftoff that inherently reduce pattern fidelity, the resolution of the final pattern was kept close to that of the lithographic step. Magnetic force microscopy (MFM) showed magnetic isolation of the patterned bits at 1.9 Tbit/in(2), which was close to the resolution limit of the MFM. The method presented will enable studies on magnetic bits packed at ultra-high densities, and can be combined with other scalable patterning methods such as templated self-assembly and nanoimprint lithography for high-volume manufacturing.     

Life‐cycle‐integrated thermoeconomic and enviroeconomic assessments of the small‐scale‐liquefied natural gas cold utilization systems

Small‐scale‐liquefied natural gas (LNG) cold‐utilized power generation systems are the sustainable solutions in the rural and inland areas where the large‐scale power generation is infeasible. This study investigates three different small‐scale LNG cold‐utilized power generation systems, which are called as the single, combined, and carbon dioxide (CO₂)–reduced combined systems according to their design details. The assessments are done according to the life‐cycle‐based enviroeconomic and life‐cycle‐integrated thermoeconomic assessment (LCiTA) models that are recently developed and new approaches, in order to better monitor their feasibilities in real operations. The life‐cycle‐based enviroeconomic assessment shows that the combined system has the lowest environmental payback period with 7.35 years that is nearly 6 months and 1 year lower than the single and CO₂‐reduced combined systems, respectively. The LCiTA study deduces that the combined system has the minimum levelized product cost while the single system has the highest values. The integration of CO₂ capture components increases the levelized product cost nearly by 16.0% in the combined design, but the levelized product cost value is still found lower than the single system. Moreover, the sustainability performance of the systems is evaluated according to the improved sustainability index calculated by the life‐cycle‐integrated fuel and destruction costs. The index value of the combined system is twice that of the single system. The multiobjective optimization study is performed in cases of closed operation rooms. The best trade‐off points are found in the close ambient air temperature range between 300.50 and 302.00 K. To observe the dynamic outdoor performance, the finite sum approach is applied for the LCiTA model. The highest fluctuations are seen for the CO₂‐reduced combined system while the smallest fluctuations belong to the combined system.     

杀菌和复热工艺对黄焖鸡挥发性风味物质的影响

为探究杀菌和复热工艺对黄焖鸡产品风味品质的影响,采用固相微萃取-气相色谱-质谱法对产品杀菌和复 热前后的挥发性风味物质进行分析,并比较产品中特征风味物质的变化情况。结果表明：杀菌和复热前后的黄焖 鸡产品中检出的挥发性风味物质主要包括醇类、醛类、酮类、酯类、酸类、烃类和杂环化合物,其中醛类化合物 是主要的挥发性风味物质,尤以己醛的含量最高;杀菌和复热工艺均可使产品本身的鸡肉风味有所增强,其中杀 菌后产品中烃类化合物和乳酸乙酯的含量显著降低,鸡肉产品的特征风味物质1-辛烯-3-醇和2-正戊基呋喃的含量显 著增加,复热后产品中由短链脂肪酸生成的酯含量显著降低,鸡肉产品的特征风味物质烯醛、二烯醛和6-甲基-5-庚 烯-2-酮的含量显著增加。     

Neural Network Approach for Linearization of the Electrostatically Actuated Double-Gimballed Micromirror

In this paper, a hierarchical circuit based approach is used for the development of a reduced-order macro-model for a double-gimballed electrostatic torsional micromirror. The nonlinearity and cross-axis coupling of the micromirror subjected to the differential driving scheme are investigated using the proposed macro-model. The simulation results are used to train a feed-forward neural network which carries out a function approximation of the relation between the desired location and the required driving voltages. The trained neural network is then coded into MAST AHDL. System-level simulation of the micromirror together with the neural network is performed in the SABER simulator. It is found that using a feed-forward neural network, the linearity of the micromirror is greatly improved, the steady state of the cross-axis coupling is reduced to a negligible level and the transient response of the cross-axis coupling is also suppressed. This implies that introducing a feed-forward neural network would be useful to simplify the design of the feedback control system for the double-gimballed electrostatic torsional micromirror.     

Influence of the processing methods on the properties of poly(lactic acid)/halloysite nanocomposites

The influence of processing methods on the thermo‐mechanical properties of poly (lactic acid) (PLA) nanocomposites were investigated by preparing nanocomposites reinforced by halloysite nanotubes (HNTs) (from 0 to 10 [w/w%]) using solution casting (SC) and melt compounding (MC) methods. Statistical analysis revealed that the processing methods have a significant influence on the tensile properties, where nanocomposites prepared by MC have higher tensile properties compared to those by SC. Experimental results illustrated higher tensile strength and a drop in ductility under the higher strain rate as compared to the low strain rate for PLA/HNTs nanocomposites. At lower concentrations micrographs revealed that, HNTs dispersion was better for SC films as compared to MC, but more prominent HNTs aggregation at higher loadings. MC nanocomposites exhibited a high crystallinity as compared to SC, due to the recrystallization and nucleation effects. The thermal stability and activation energy increased with addition of HNTs, regardless of the processing methods. POLYM. COMPOS., 37:861–869, 2016. © 2014 Society of Plastics Engineers     

Effect of stressed-skin action on optimal design of cold-formed steel square and rectangular-shaped portal frame buildings

Cold-formed steel (CFS) portal frames can be a viable alternative to conventional hot-rolled steel portal frames. They are commonly used for low-rise commercial, light industrial and agricultural buildings. In this paper, the effect of stressed-skin action on the optimum design of CFS portal frames is investigated by conducting a minimum cost design optimisation on a building of span of 6 m, height-to-eaves of 3 m and frame spacing of 3 m; the effect of different number of bays are considered. For the purpose of this study, it is assumed that gables are rigid.The effect of stressed-skin action is larger for“square-shaped” buildings (i.e. when the span and length are the same on plan) and decreases as more bays are added(i.e. as the building becomes more “rectangular-shaped” on plan). The results of the minimum cost optimisation indicate that if stressed-skin action is taken into account, the cost of the internal frame can be reduced by around half for “square-shaped” buildings. It should be noted that this is a minimum cost optimisation, which is not the same as a minimum weight optimisation. It is also shown that a safe design of internal frames could be obtained by ignoring wind loads (i.e. designing the frame only for gravity loads),but this is limited to buildings having a “square-shape”.     

Real-time 3D human capture system for mixed-reality art and entertainment

A real-time system for capturing humans in 3D and placing them into a mixed reality environment is presented in this paper. Nine cameras surrounding her capture the subject. Looking through a head-mounted-display with a camera in front pointing at a marker, the user can see the 3D image of this subject overlaid onto a mixed reality scene. The 3D images of the subject viewed from this viewpoint are constructed using a robust and fast shape-from-silhouette algorithm. The paper also presents several techniques to produce good quality and speed up the whole system. The frame rate of our system is around 25 fps using only standard Intel processor-based personal computers. Besides a remote live 3D conferencing and collaborating system, we also describe an application of the system in art and entertainment, named Magic Land, which is a mixed reality environment where captured avatars of human and 3D computer generated virtual animations can form an interactive story and play with each other. This system demonstrates many technologies in human computer interaction: mixed reality, tangible interaction, and 3D communication. The result of the user study not only emphasizes the benefits, but also addresses some issues of these technologies.