Because mass propagation velocity has a finite value in porous media for an unsteady mass transfer process, the hypothesis that mass propagation velocity in mass transfer process is infinite is far away from practical situation for high intense drying process in wet porous materials. Like heat transfer, a description of an unsteady humidity profile in the form of the hyperbolic equation is advanced. From the equation, wave characteristic can be seen in the mass transfer field of inner material. One-dimensional hyperbolic equation of mass transfer for high intense drying process of wet porous materials has been developed in this paper. The non-Fick phenomena in high intense drying process are analyzed by the comparison of the solutions between the Fick equation and the non-Fick equation. The calculating results show that when mass flux or mass transfer coefficient is high, the non-Fick effect is notable and it is not negligible in an intense drying process.
Abstract Background: Regulatory T cells (Treg)/T helper (Th) 17 skewing plays a crucial role in development of acute respiratory distress (ARDS). Mesenchymal stem cells (MSCs)-secreted transforming growth factor (TGF)-β1 has remarkable immunomodulatory effects on CD4 + T cells, being environment sensitive and remains lack of discussion in hypoxic and inflammatory condition of ARDS. Methods: Purified mice splenic CD4 + T cells were pre-coated with anti-CD3 (5ug/ml) and anti-CD28 (2ug/ml) overnight. RAW264.7 cells were added as antigen presenting cells (APCs). T cells with and without RAW264.7 cells were treated with various LPS concentrations of 0,10,100,1000ng/ml or/and at hypoxia condition of 5% O2. Based on LPS (100ng/ml) and hypoxia condition (5% O2) as stimuli, MSCs were set in direct coculture or indirect coculture methods by transwell system. Anti-TGF-β1 neutralization antibody was added to explore the role of TGF-β1 among the soluble factors secreted by MSCs; miR-155 overexpression of CD4+T cells were performed by transfection and then were added to the MSCs-CD4 + T cells coculture system in hypoxic and LPS-stimulated condition. After 48 hours, cells or supernatant were collected for detection of frequency of Treg and Th17 subsets, CD4 + T cells apoptosis and proliferation capacity assay by flowcytometry, secretions of INF-γ, IL-17A, IL-21, TGF-β1 and IL-10 by ELISA, levels of miR-155, Rorc, Foxp3 and Ptpn2 mRNA expression of CD4 + T cells by RT-PCR. Results: MSCs could restore the skewed Treg/Th17 induced by LPS and hypoxia as compared to groups without MSCs with increased secretion of TGF-β1, IL-10 and IL-17A(P<0.05) and attenuate the increased expression of miR-155 in CD4 + T cells, which was independent on cell-to-cell contact mechanism while TGF-β1 neutralization could significantly inhibit the effects of MSCs restoring the skewed Treg/Th17 and abolished its effect on miR-155 expression in CD4 + T cells. Conclusions: These findings suggested miR-155 suppression of CD4 + T cells mediated MSCs-secreted TGF-β1 modulating the skewed Treg/Th17 induced by LPS-hypoxia challenge, providing evidence when proposing future T lymphocyte-targeted cell therapy in ARDS.
This study characterized chemical and structural properties and biodegradability of dissolved organic matter (DOM) derived from rice straw decay to evaluate the stabilization of DOM in soil systems. Five different DOM samples were obtained at different times of straw decay under laboratory conditions. The biodegradation rates of these five DOM samples were measured using a microcosm technique. The DOM before and after degradation tests was characterized using different chemical and spectroscopic methods. The results showed that the DOM production from straw decay decreased initially, then increased linearly as a function of time, and finally leveled off beyond 63 days. The biodegradation rates of DOM harvested at different decay times were adequately quantified using a two-compartment kinetics equation. The model fitting results showed that the relative content of the biologically resistant DOM fraction increased from 7% in the DOM obtained at Day 0 of decay to about 63% in the DOM at Day 180 of decay. The half lives of the labile and the resistant DOM fractions were 1.22 to 3.07 days and 36 to 630 days, respectively. Fourier transform infrared spectra, 1H-nuclear magnetic resonance spectra, and 13C-nuclear magnetic resonance spectra indicated that carbohydrates may be the major components of the labile DOM fraction, and that lignin-derived aromatic organic compounds may be the major components of the resistant DOM fraction. The increased resistance of DOM to further biodegradation may suggest enhanced carbon sequestration in soils.
Abstract A canned motor pump is widely used for transporting the liquids without leakage. In this work, the pump is applied for heat supply system. For this application, between the rotor and stator for cooling the canned motor there is a circulating flow, which will flow back in the pump passage with higher temperature, and bring the mixing of the liquid having different temperature between the main stream and the circulating flow. The steady state internal flow has been investigated for the pump, and the pump hydraulic performance has been compared with the experimental data. With the consideration of both mechanical energy and internal energy as the effective energy increment of the working fluid, an efficiency assessment is proposed for a canned motor pump. The proposed efficiency shows the same tendency as hydraulic efficiency, and is more understandable compared with that of the conventional method. The present results indicate that the proposed method of evaluating the efficiency of the canned motor pump can reasonably depict the energy balance inside the whole canned motor pump. Further, the introduction of circulating flow is helpful to predict the internal flow and heat transfer for the canned motor pump in numerical simulation with better accuracy. The present study is helpful for both development and application of high performance canned motor pump for various industries.
The basic rule and influence factors on deposition of ZrO2 and ZrO2_Y2O3 coatings by high energy pulse were studied. After the oxidizing experiment in air at 1 000 for 100 h, it was shown that the oxidation resistance of 18_8 stainless steel was marketly enhanced by depositing ZrO2 and ZrO2_Y2O3 coatings. The oxidation resistance was increased about 20 times and the oxide scale spallation resistance was increased about 100 times.
Active learning aims to improve the performance of task model by selecting the most informative samples with a limited budget. Unlike most recent works that focused on applying active learning for image classification, we propose an effective Consistency-based Active Learning method for object Detection (CALD), which fully explores the consistency between original and augmented data. CALD has three appealing benefits. (i) CALD is systematically designed by investigating the weaknesses of existing active learning methods, which do not take the unique challenges of object detection into account. (ii) CALD unifies box regression and classification with a single metric, which is not concerned by active learning methods for classification. CALD also focuses on the most informative local region rather than the whole image, which is beneficial for object detection. (iii) CALD not only gauges individual information for sample selection, but also leverages mutual information to encourage a balanced data distribution. Extensive experiments show that CALD significantly outperforms existing state-of-the-art task-agnostic and detection-specific active learning methods on general object detection datasets. Based on the Faster R-CNN detector, CALD consistently surpasses the baseline method (random selection) by 2.9/2.8/0.8 mAP on average on PASCAL VOC 2007, PASCAL VOC 2012, and MS COCO. Code is available at \url{https://github.com/we1pingyu/CALD}
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