Modeling asphalt pavement overlay transverse cracks using the genetic operation tree and Levenberg-Marquardt Method

[[abstract]]The Artificial Neural Network (ANN) and the nonlinear regression method are commonly used to build models from experimental data. However, the ANN has been criticized for incapable of providing clear relationships and physical meanings, and is usually regarded as a black box. The nonlinear regression method needs predefined and correct formula structures to process parameter search in terms of the minimal sum of square errors. Unfortunately, the formula structures of these models are often unclear and cannot be defined in advance. To overcome these challenges, this study proposes a novel approach, called ââLMGOT,ââ that integrates two optimization techniques: the LevenbergâMarquardt (LM) Method and the genetic operation tree (GOT). The GOT borrows the concept from the genetic algorithm, a famous algorithm for solving discrete optimization problems, to generate operation trees (OTs), which represent the structures of the formulas. Meanwhile, the LM takes advantage of its merit for solving nonlinear continuous optimization problems, and determines the coefficients in the GOTs that best fit the experimental data. This paper uses the LMGOT to investigate the data sets of pavement cracks from a 15-year experiment conducted by the Texas Departments of Transportation. Results show a concise formula for predicting the length of pavement transverse cracking, and indicate that the LMGOT is an efficient approach to building an accurate crack model.[[incitationindex]]SCI[[booktype]]紙

Quantum phase transition in the Frenkel-Kontorova chain: from pinned instanton glass to sliding phonon gas

We study analytically and numerically the one-dimensional quantum Frenkel-Kontorova chain in the regime when the classical model is located in the pinned phase characterized by the gaped phonon excitations and devil's staircase. By extensive quantum Monte Carlo simulations we show that for the effective Planck constant $\hbar$ smaller than the critical value $\hbar_c$ the quantum chain is in the pinned instanton glass phase. In this phase the elementary excitations have two branches: phonons, separated from zero energy by a finite gap, and instantons which have an exponentially small excitation energy. At $\hbar=\hbar_c$ the quantum phase transition takes place and for $\hbar>\hbar_c$ the pinned instanton glass is transformed into the sliding phonon gas with gapless phonon excitations. This transition is accompanied by the divergence of the spatial correlation length and appearence of sliding modes at $\hbar>\hbar_c$.Comment: revtex 16 pages, 18 figure

Modeling on fluid flow and inclusion motion in centrifugal continuous casting strands

During the centrifugal continuous casting process, unreasonable casting parameters can cause violent level fluctuation, serious gas entrainment, and formation of frozen shell pieces at the meniscus. Thus, in the current study, a three-dimensional multiphase turbulent model was established to study the transport phenomena during centrifugal continuous casting process. The effects of nozzle position, casting and rotational speed on the flow pattern, centrifugal force acting on the molten steel, level fluctuation, gas entrainment, shear stress on mold wall, and motion of inclusions during centrifugal continuous casting process were investigated. Volume of Fluid model was used to simulate the molten steel-air two-phase. The level fluctuation and the gas entrainment during casting were calculated by user-developed subroutines. The trajectory of inclusions in the rotating system was calculated using the Lagrangian approach. The results show that during centrifugal continuous casting, a large amount of gas was entrained into the molten steel, and broken into bubbles of various sizes. The greater the distance to the mold wall, the smaller the centrifugal force. Rotation speed had the most important influence on the centrifugal force distribution at the side region. Angular moving angle of the nozzle with 8° and keeping the rotation speed with 60 revolutions per minute can somehow stabilize the level fluctuation. The increase of angular angle of nozzle from 8 to 18 deg and rotation speed from 40 to 80 revolutions per minute favored to decrease the total volume of entrained bubbles, while the increase of distance of nozzle moving left and casting speed had reverse effects. The trajectories of inclusions in the mold were irregular, and then rotated along the strand length. After penetrating a certain distance, the inclusions gradually moved to the center of billet and gathered there. More work, such as the heat transfer, the solidification, and the inclusions entrapment during centrifugal continuous casting, will be performed

7th Drug hypersensitivity meeting: part two

No abstract availabl

Search for gravitational-wave transients associated with magnetar bursts in advanced LIGO and advanced Virgo data from the third observing run

Gravitational waves are expected to be produced from neutron star oscillations associated with magnetar giant f lares and short bursts. We present the results of a search for short-duration (milliseconds to seconds) and longduration (∼100 s) transient gravitational waves from 13 magnetar short bursts observed during Advanced LIGO, Advanced Virgo, and KAGRA’s third observation run. These 13 bursts come from two magnetars, SGR1935 +2154 and SwiftJ1818.0−1607. We also include three other electromagnetic burst events detected by FermiGBM which were identified as likely coming from one or more magnetars, but they have no association with a known magnetar. No magnetar giant flares were detected during the analysis period. We find no evidence of gravitational waves associated with any of these 16 bursts. We place upper limits on the rms of the integrated incident gravitational-wave strain that reach 3.6 × 10−²³ Hz at 100 Hz for the short-duration search and 1.1 ×10−²² Hz at 450 Hz for the long-duration search. For a ringdown signal at 1590 Hz targeted by the short-duration search the limit is set to 2.3 × 10−²² Hz. Using the estimated distance to each magnetar, we derive upper limits upper limits on the emitted gravitational-wave energy of 1.5 × 1044 erg (1.0 × 1044 erg) for SGR 1935+2154 and 9.4 × 10^43 erg (1.3 × 1044 erg) for Swift J1818.0−1607, for the short-duration (long-duration) search. Assuming isotropic emission of electromagnetic radiation of the burst fluences, we constrain the ratio of gravitational-wave energy to electromagnetic energy for bursts from SGR 1935+2154 with the available fluence information. The lowest of these ratios is 4.5 × 103

A micromachined resistive-type humidity sensor with a composite material as sensitive film

A novel resistive-type humidity microsensor was fabricated by a microelectromechanical system (MEMS) technology and thick-film technology. The microsensor was composed of a suspended planar membrane bridged to the base silicon substrate with two beams. Metal electrodes were deposited on the surface of the membrane, and a composite film of poly-[3-(methacryloylamino)propyl] trimethyl ammonium chloride and SiO2 (PMAPTAC/SiO2) was coated as a humidity-sensing material on the top of the electrodes. The humidity-sensing principle of the sensor was based on the conductivity change of coated composite film upon adsorption/desorption of water vapor. The logarithmic impedance of the microsensor measured at 1 kHz decreased linearly with increasing the humidity in the range of 30-90%RH. The applied voltage above I V did not influence the humidity response of the microsensor. The maximum difference between humidification and desiccation process was 5.1%RH at 30%RH. The influence of temperature was -0.72%RH/degrees C on average in the temperature range 15-25 degrees C and the humidity range of 30-90%RH. (c) 2005 Elsevier B.V. All Rights reserved

Colonic interleukin-6 expression is induced by intestinal inflammation and dietary iron

Chronic intestinal inflammation and high dietary iron are associated with a greater risk of developing colorectal cancer. The aim of this study was to investigate the role of IL-6 in iron-induced colonic inflammation and tumourigenesis in a mouse model of colorectal cancer. Methods: Mice, fed either an iron-supplemented (1% carbonyl iron) or control (0.01% iron) diet, were treated with dextran sodium sulphate (DSS) and azoxymethane (AOM) to induce intestinal inflammation and cancer. Intestinal inflammation and tumour development were assessed using high-resolution video endoscopy at multiple time-points. Colonic inflammation and tumours were examined histologically and gene expression by real-time PCR. Results: Seven days post-AOM/DSS treatment, intestinal inflammation was more severe in iron-loaded mice (p < 0.05). Colonic pro-inflammatory cytokines, IL-6, IFN-γ and TNFα gene expression increased with AOM/ DSS treatment confirming the presence of intestinal inflammation (p < 0.05). Dietary iron loading had an additive effect on the gene expression of IL-6 and other members of this family, IL-11 and IL-17a, in AOM/ DSS-treated mice. STAT3 phosphorylation was increased in AOM/DSS treated mice and this was further enhanced with dietary iron loading. Five weeks after AOM/DSS treatment, iron-loaded mice developed a greater number and larger-sized colonic tumours compared to control mice (p < 0.05). Dietary iron-loading also induced an additive effect on tumour IL-6 gene expression in AOM/DSS-treated mice (p < 0.05). Expression of cellular iron import genes DMT1, Zip14a and Tfr1 was increased and cellular export gene ferroportin was reduced in colonic tumours compared to non-tumour tissue from the same animal (p < 0.05), suggesting increased iron uptake by tumours may promote growth. Summary/Conclusions: Dietary iron-loading promoted colonic inflammation and tumour formation. The mechanistic basis for the interaction between iron, inflammation and colorectal cancer may involve IL-6/ STAT3 signalling

Liver iron homeostasis is altered by colonic inflammation and dietary iron

Background Patients with inflammatory bowel diseases (IBD) develop anaemia of inflammation (AI) due to disturbances in iron homeostasis that limits the availability of iron for erythropoiesis. Aims In this study, the effects of colonic inflammation and dietary iron levels on liver iron homeostasis were investigated in a mouse model of colitis. Methods Colonic inflammation was induced by the administration of dextran sodium sulphate (DSS) to mice fed either an iron-supplemented (1%) or control iron (0.01%) diet. Liver and plasma iron concentrations as well as plasma transferrin saturation were measured biochemically. Liver gene expression was determined by real-time PCR and plasma IL-6 levels were measured by ELISA. Results DSS-induced colonic inflammation increased plasma IL-6 levels. Dietary iron supplementation further enhanced colonic inflammation and plasma IL-6 levels (p < 0.0001). Liver iron and plasma transferrin saturation were elevated in dietary iron-supplemented mice. Post-DSS treatment, liver iron levels increased (p < 0.01) and transferrin saturation decreased (p < 0.01) in mice fed the iron-supplemented and control iron diets, consistent with the presence of AI. Liver expression of the iron regulatory genes, hepcidin (Hamp1) and inhibitor of DNA binding 1 (Id1), was upregulated by dietary iron (p < 0.01) but unexpectedly downregulated by DSS treatment (p < 0.05). Smad7 gene expression was decreased in DSStreated mice and Bmp6 expression was increased by dietary iron supplementation (p < 0.001). Dietary iron supplementation decreased the gene expression of the iron importer transferrin receptor 1 (Tfr1), congruent with the iron-dependent regulation of Tfr1 and expression and further diminished by DSS treatment (p < 0.05). Gene expression of the iron importer Zip14 was increased (p < 0.05) whilst that of the iron exporter ferroportin 1A was decreased (p < 0.0001) with DSS treatment, consistent with the retention of iron by the liver. Conclusion The perturbations in iron homeostasis resulting from increased colonic inflammation observed in this study are consistent with AI. The regulatory pathways for the changes seen, however, are unclear. The lack of induction of Hamp1 expression by plasma IL-6 levels suggests that other regulatory signals may impede hepcidin induction by inflammation. A possible candidate is the erythroid signal as increased erythropoietic activity is known to be a strong negative regulator of hepcidin

IL-2 receptor beta-chain signaling controls immunosuppressive CD4+ T cells in the draining lymph nodes and lung during allergic airway inflammation in vivo.

IL-2 influences both survival and differentiation of CD4(+) T effector and regulatory T cells. We studied the effect of i.n. administration of Abs against the alpha- and the beta-chains of the IL-2R in a murine model of allergic asthma. Blockade of the beta- but not the alpha-chain of the IL-2R after allergen challenge led to a significant reduction of airway hyperresponsiveness. Although both treatments led to reduction of lung inflammation, IL-2 signaling, STAT-5 phosphorylation, and Th2-type cytokine production (IL-4 and IL-5) by lung T cells, IL-13 production and CD4(+) T cell survival were solely inhibited by the blockade of the IL-2R beta-chain. Moreover, local blockade of the common IL-2R/IL-15R beta-chain reduced NK cell number and IL-2 production by lung CD4(+)CD25(+) and CD4(+)CD25(-) T cells while inducing IL-10- and TGF-beta-producing CD4(+) T cells in the lung. This cytokine milieu was associated with reduced CD4(+) T cell proliferation in the draining lymph nodes. Thus, local blockade of the beta-chain of the IL-2R restored an immunosuppressive cytokine milieu in the lung that ameliorated both inflammation and airway hyperresponsiveness in experimental allergic asthma. These findings provide novel insights into the functional role of IL-2 signaling in experimental asthma and suggest that blockade of the IL-2R beta-chain might be useful for therapy of allergic asthma in humans