On anisotropic elasticity and questions concerning its Finite Element implementation

We give conditions on the strain–energy function of nonlinear anisotropic hyperelastic materials that ensure compatibility with the classical linear theories of anisotropic elasticity. We uncover the limitations associated with the volumetric–deviatoric separation of the strain–energy used, for example, in many Finite Element (FE) codes in that it does not fully represent the behavior of anisotropic materials in the linear regime. This limitation has important consequences. We show that, in the small deformation regime, a FE code based on the volumetric–deviatoric separation assumption predicts that a sphere made of a compressible anisotropic material deforms into another sphere under hydrostatic pressure loading, instead of the expected ellipsoid. For finite deformations, the commonly adopted assumption that fibres cannot support compression is incorrectly implemented in current FE codes and leads to the unphysical result that under hydrostatic tension a sphere of compressible anisotropic material deforms into a larger sphere.     

HEALPIX DCT technique for compressing PCA-based illumination adjustable images

An illumination adjustable image (IAI), containing a set of pre-captured reference images under various light directions, represents the appearance of a scene with adjustable illumination. One of drawbacks of using the IAI representation is that an IAI consumes a lot of memory. Although some previous works proposed to use blockwise principal component analysis for compressing IAIs, they did not consider the spherical nature of the extracted eigen-coefficients. This paper utilizes the spherical nature of the extracted eigen-coefficients to improve the compression efficiency. Our compression scheme consists of two levels. In the first level, the reference images are converted into a few eigen-images (floating point images) and a number of eigen-coefficients. In the second level, the eigen-images are compressed by a wavelet-based method. The eigen-coefficients are organized into a number of spherical functions. Those spherical coefficients are then compressed by the proposed HEALPIX discrete cosine transform technique.     

Removal of pentane and styrene mixtures from waste gases by a trickle‐bed air biofilter

The biofilter process is a relatively new technology that has been proven to be more cost‐effective than traditional technologies for treating many kinds of volatile organic compounds (VOCs) from waste gases. Pentane and styrene mixtures are commonly encountered in the manufacture of polymers such as polystyrene. This research attempts to employ a trickle‐bed air biofilter (TBAB) for treating such mixtures under different influent carbon loadings. In the pseudo‐steady‐state conditions, the elimination capacities of pentane and styrene increased but the removal efficiencies decreased with increased influent carbon loading. The removal efficiencies of styrene were higher than those of pentane, indicating that styrene is a preferred substrate and the differences were enhanced at a high carbon loading. Removal efficiencies of more than 80% were achieved with influent carbon loadings of pentane and styrene below 25 and 68 gm^?3 h^?1, respectively. The TBAB appears to be efficient for controlling VOC emissions with low pentane and medium styrene loadings, and the effectiveness could be maintained over 140 days of laboratory operation. © 2001 Society of Chemical Industry     

Constant-Isomer Benzenoid Series and a Topological Paradigm

The separate sets of constant-isomer benzenoid monoradicals, diradicals, triradicals, tetraradicals, etc. have the same sequence of isomer number counts. Those monoradicals, diradicals, triradicals, tetraradicals, etc. with the same isomer numbers also have a one-to-one topological matching among the member benzenoids.     

Hygroscopic Growth and Deposition of Inhaled Secondary Cigarette Smoke in Human Nasal Pathways

To ascertain the threat to human health posed by the inhalation of the particulate phase for secondary cigarette smoke (SCS), it is necessary to determine the doses delivered to airway cells. The risk assessment of SCS particles is complicated by their hygroscopic properties. Inhaled particles that are hygroscopic may absorb the water vapor that is present in a warm, humid environment such as that found in the human respiratory system. As a direct result, the physicochemical characteristics of a particle such as size, shape, density, and composition may experience significant changes. Herein, the effects of hygroscopicity and deposition of SCS particles are examined in the nasopharyngeal region of the respiratory tract through which particles travel before entering the lung. To accomplish this goal, a computer model is defined to describe the anatomical features of the airways within the human head and throat. Then the effects of water vapor uptake and deposition on inhaled particle size distributions are formulated. The results of the simulations indicate that hygroscopicity is a critical factor affecting the dynamics of inhaled SCS.     

The Shaping of Housing Histories in Shanghai

During the last half century or so, China has probably experienced more dramatic and fundamental changes than most other societies. Housing and family life have been embedded in a series of far-reaching societal changes, notably the communist victory of 1949, the period of the Cultural Revolution and the more recent drive towards a more market oriented society, with housing reforms at the forefront. This paper examines the way in which housing histories among families in Shanghai were shaped by these events and by their interaction with specific intergenerational dynamics. The paper draws on research carried out in Shanghai in 2008 which involved in-depth interviews with individual members of three linked generations. The research provides a unique account of family housing histories over three generations against a particularly turbulent backcloth.     

New Method for Determining the Nucleation and Crystal-Growth Rates in Glasses

The rates for nucleation ( I ) and crystal growth ( U ) for a lithium disilicate (Li₂O·2SiO₂, LS₂) glass were determined, as a function of temperature, using a new differential thermal analysis (DTA) technique. This technique requires in situ nucleation and crystal-growth heat treatment of a small amount of powdered sample inside the DTA apparatus, which then are followed by a DTA scan at a constant heating rate. The I and U values that have been determined at selected temperatures for the LS₂ glass are in excellent agreement with those reported in the literature. The technique also has been used to determine the concentration of quenched-in nuclei in LS₂ glasses prepared from melts that have been quenched at different rates, which are in reasonable agreement with those estimated from theoretical considerations. This new DTA technique is less tedious, requires a smaller amount of sample, and is at least 10 times faster than the conventional methods that have been used to measure I and U . Also, no special sample preparation, other than simply grinding and screening the glass to a particle size that is suitable for use, is required in this technique, whereas grinding, polishing, or etching is required in conventional methods. The excellent agreement in the I or U values that have been determined for the LS₂ glass via the present and conventional methods demonstrates the accuracy, validity, and usefulness of this DTA method for rapid determination of the nucleation and crystal-growth rates in glasses.     

RFID-enabled real-time manufacturing execution system for mass-customization production

Mass-customization production (MCP) companies must fight with shop-floor uncertainty and complexity caused by wide variety of product components. The research is motivated by a typical MCP company that has experienced inefficient scheduling due to paper-based identification and manual data collection. This paper presents an RFID-enabled real-time manufacturing execution system (RT-MES). RFID devices are deployed systematically on the shop-floor to track and trace manufacturing objects and collect real-time production data. Disturbances are identified and controlled within RT-MES. Planning and scheduling decisions are more practically and precisely made and executed. Online facilities are provided to visualize and manage real-time dynamics of shop-floor WIP (work-in-progress) items. A case study is reported in a collaborating company which manufactures large-scale and heavy-duty machineries. The efficiency and effectiveness of the proposed RT-MES are evaluated with real-life industrial data for shop-floor production management in terms of workers, machines and materials.     

Hydromagnetic stability of plane Poiseuille flow of an Oldroyd fluid

Summary The linear stability of plane Poiseuille flow of a conducting Oldroyd liquid in the presence of a transverse magnetic field is studied. The fourth-order Orr-Sommerfeld equation governing the stability analysis in this case is solved numerically by a spectral method.