58 research outputs found
Analytical Calculation of Coupled Magnetothermal Problem in Gas Insulated Transmission Lines
Gas insulated transmission lines (GIL) are a new technology for transmitting power over long distances. In this paper, an analytical method (AM) is proposed to investigate the coupled magnetothermal problem in GIL. Kelvin functions are employed to calculate the skin effect coefficients of the conductor and the enclosure. The calculated power losses are used as heat source input for the thermal analysis. Considering the convective and radiation heat transfer effects, the heat balance equations on the surface of the conductor and the enclosure are established, respectively. Temperature rise of the GIL at different operation conditions are investigated. The proposed method is validated against the finite element method (FEM). The simplicity of the approach makes it attractive for self-made software implementation in the thermal design and the condition monitoring of GIL
A novel scale-down cell culture and imaging design for the mechanistic insight of cell colonization within porous substrate
At the core of translational challenges in Tissue Engineering is the mechanistic understanding of the underpinning biological processes and the complex relationships among components at different levels, which is a challenging task due to the limitations of current tissue culture and assessment methodologies. Therefore, we proposed a novel scale-down strategy to deconstruct complex bio-matrices into elementary building blocks, which were resembled by thin modular substrate and then evaluated separately in miniaturised bioreactors using various conventional microscopes. In order to investigate cell colonization within porous substrate in this proof-of-concept study, TEM specimen supporters (10-30µm thick) with fine controlled open pores (100~600µm) were selected as the modular porous substrate and suspended in 3D printed bioreactor systems. Non-invasive imaging of human dermal fibroblasts cultured on these free-standing substrate using optical microscopes illustrated the complicated dynamic processes used by both individual and coordinated cells to bridge and segment porous structures. Further in situ analysis via SEM and TEM provided high quality micrographs of cell-cell and cell-scaffold interactions at micro-scale, depicted cytoskeletal structures in stretched and relaxed areas at nano-scale. Thus this novel scaled-down design was able to improve our mechanistic understanding of tissue formation not only at single- and multiple-cell levels, but also at micro- and nano-scales, which could be difficult to obtain using other methods
Convergence of regional economic cycles in Turkey
Dissimilar economic fluctuations and asymmetric shocks across the regions of a country might create severe policy distortions that, under these circumstances, aggregate policy interventions (such as taxation and interest rates), are likely to be sub-optimal for at least a fraction of the regions. For instance, monetary policy can hardly satisfy the needs of all regions when some of the regions are experiencing a boom while others are in a recession phase. For these reasons, similarity of regional business cycles and their convergence are highly desirable from a policy viewpoint. The aim of this paper is, therefore, to provide empirical evidence and policy implications in that context. In particular, I analyze business cycle correlations across Turkish provinces and the tendency of these cycles to converge over the period of analysis between 1975-2000 and 2004-2008 (for Nomenclature of Territorial Units for Statistics [NUTS]-2 regions). I find that regional business cycle asymmetries have tended to decrease in recent decades. This result, although it seems to provide evidence in favor of rising correlations, shows that the convergence process is rather slow and there still exist asymmetries across the regional business cycles
Adaptive Quantization for Predicting Transform-based Point Cloud Compression
The representation of three-dimensional objects with point clouds is attracting increasing interest from researchers and practitioners. Since this representation requires a huge data volume, effective point cloud compression techniques are required. One of the most powerful solutions is the Moving Picture Experts Group geometry-based point cloud compression (G-PCC) emerging standard. In the G-PCC lifting transform coding technique, an adaptive quantization method is used to improve the coding efficiency. Instead of assigning the same quantization step size to all points, the quantization step size is in-creased according to level of detail traversal order. In this way, the attributes of more important points receive a finer quantization and have a smaller quantization error than the attributes of less important ones. In this paper, we adapt this approach to the G-PCC predicting transform and propose a hardware-friendly weighting method for the adaptive quantization. Experimental results show that compared to the current G-PCC test model, the proposed method can achieve an average Bjøntegaard delta rate of -6.7%, -14.7%, -15.4%, and -10.0% for the luma, chroma Cb, chroma Cr, and reflectance components, respectively on the MPEG Cat1-A, Cat1-B, Cat3-fused and Cat3-frame datasets
Facile fabrication of multi-hydrogen bond self-assembly poly(Maac-co-maam) hydrogel modified pvdf ultrafiltration membrane to enhance anti-fouling property
In this work, a facile preparation method was proposed to reduce natural organics fouling of hydrophobic membrane via UV grafting polymerization with methacrylic acid (MAAc) and methyl acrylamide (MAAm) as hydrophilic monomers, followed by multihydrogen bond self-assembly. The resulting poly(vinylidene fluoride)-membranes were characterized with respect to monomer ratio, chemical structure and morphology, surface potential, and water contact angle, as well as water flux and organic foulants ultrafiltration property. The results indicated that the optimal membrane modified with a poly(MAAc-co-MAAm) polymer gel layer derived from a 1:1 monomer ratio exhibited superior hydrophilicity and excellent gel layer stability, even after ultrasonic treatment or soaking in acid or alkaline aqueous solution. The initial water contact angle of modified membranes was only 36.6° ± 2.9, and dropped to 0° within 13 s. Moreover, flux recovery rates (FRR) of modified membranes tested by bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA) solution, respectively, were all above 90% after one-cycle filtration (2 h), significantly higher than that of the pure membrane (70–76%). The total fouling rates (R) of the pure membrane for three foulants were as high as 47.8–56.2%, while the Rt values for modified membranes were less than 30.8%. Where R of BSA dynamic filtration was merely 10.7%. The membrane designed through grafting a thin-layer hydrophilic hydrogel possessed a robust antifouling property and stability, which offers new insights for applications in pure water treatment or protein purificatio
The construction of competency training mechanism model for tourism undergraduates based on grounded theory
Comparison of competency recognition accuracy between grounded theory and content analysis method.
Comparison of competency recognition accuracy between grounded theory and content analysis method.</p
Statistics of the grading results of tourism majors based on different competency training mechanisms (A1: Practical ability; A2: Innovative ability; A3: Cooperation ability; A4: Lifelong learning ability).
Statistics of the grading results of tourism majors based on different competency training mechanisms (A1: Practical ability; A2: Innovative ability; A3: Cooperation ability; A4: Lifelong learning ability).</p
Comparison of standard errors of training programs for tourism majors with different competency training mechanisms (B1: Logical thinking ability; B2: Communication skills; B3: Foresight consciousness; B4: Information technology capability).
Comparison of standard errors of training programs for tourism majors with different competency training mechanisms (B1: Logical thinking ability; B2: Communication skills; B3: Foresight consciousness; B4: Information technology capability).</p
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