453 research outputs found

    Effect of temperature stress on main structure in waste incineration power generation plant

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    Waste incineration power station includes many functional structures, such as garbage discharge, storage, sorting and feeding units, boiler unit, tail gas treatment unit, leachate treatment unit, and coal storage unit. The structural forms of each part are different. Because of the particularity of garbage, structure units are required to be as close as possible and temperature joints should not be set up for the sake of possible leakage of exhaust gas or effluent liquor, so various structural units are integrated, which leads to the difficulty in structure design, and thermal stress cannot be neglected. In order to understand the effect temperature stress on main plant structures, a finite element model is established to study the distribution of thermal stress of the whole structure under three conditions: heating in summer, cooling in winter and heating in winter. It is found the influence of temperature on frame beam, column and steel space truss can be neglected, and the thermal stress on floor cannot be neglected [1]. The maximum stress is mainly distributed on both edges of floor along the longitude direction of structure. For those regions where stress concentration occurs, reinforcement bands or reinforcement mesh can be used to reduce the tensile stress. The analysis results show that this measure is effective and provides a reference for the design of the main structure of waste incineration power plant. This paper innovatively analyses the structure system of main workshop of refuse incineration power plant, which is composed of steel structure and concrete structure, and describes the skills and key points of complex system modeling. According to different seasons and heating temperature difference, the temperature stress on the surface of the structure is analyzed, which provides a reference for calculating degree stress and temperature difference of the similar structure system. The weak part of resistance to temperature stress in the structure system composed of concrete structure and steel structure is found out, and the corresponding solutions are put forward, which provides guidance for the construction of the main workshop of refuse incineration power station

    Exploring multi-year soybean yield trial data in South Dakota environments

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    Crop performance test (CPT) is a common practice to evaluate yield performance and adaptability of each cultivar. In this study, we combined 16 years of soybean CPT data, which included six representative locations, three major maturity groups, and over 1000 cultivars, to determine some patterns associated with yield production. As expected, the repeatability for these cultivars in trial over years was very low. Thus, the data processing in this study was focused on descriptive statistics regarding time, location, and seed supplier and several linear model analyses. The results will be presented during the conference

    Temperature stress of waste bunker in municipal solid waste incineration power generation plant

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    With large number of municipal solid waste incineration power generation plants appearing, serious environmental pollution will be caused if temperature cracks appear in waste bunkers. To reveal the interaction between the surrounding soil and bunker walls under the action of temperature, a finite element model is established. Considering the surrounding soil layer, the characteristics and influence laws of the interaction between the municipal solid waste bunker and the soil under different temperature conditions are studied. The simulation results show that the existence of the surrounding soil layer will affect the stress distribution, mainly at the bottom of the bunker and the surface of the bunker wall. Due to the thermal expansion and contraction, the municipal solid waste bunker is pressed during the heating process. In the process of cooling, there will be excessive tensile stress at the bottom of the bunker. To address this problem, expansion belt is arranged at the stress concentration portion to reduce the stress concentration. This measure proves to be effective according to analysis results, which provides a reference for the design of municipal solid waste bunkers

    Magnetic ordering and structural phase transitions in strained ultrathin SrRuO3_{3}/SrTiO3_{3} superlattice

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    Ruthenium-based perovskite systems are attractive because their Structural, electronic and magnetic properties can be systematically engineered. SrRuO3_3/SrTiO3_3 superlattice, with its period consisting of one unit cell each, is very sensitive to strain change. Our first-principles simulations reveal that in the high tensile strain region, it transits from a ferromagnetic (FM) metal to an antiferromagnetic (AFM) insulator with clear tilted octahedra, while in the low strain region, it is a ferromagnetic metal without octahedra tilting. Detailed analyses of three spin-down Ru-t2g_{2g} orbitals just below the Fermi level reveal that the splitting of these orbitals underlies these dramatic phase transitions, with the rotational force constant of RuO6_6 octahedron high up to 16 meV/Deg2^2, 4 times larger than that of TiO6_6. Differently from nearly all the previous studies, these transitions can be probed optically through the diagonal and off-diagonal dielectric tensor elements. For one percent change in strain, our experimental spin moment change is -0.14Ā±\pm0.06 Ī¼B\mu_B, quantitatively consistent with our theoretical value of -0.1 Ī¼B\mu_B.Comment: 3 figures, 1 supplementary material, accepted by Phys. Rev. Let

    Monte Carlo localization algorithm based on particle swarm optimization

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    In wireless sensor networks, Monte Carlo localization for mobile nodes has a large positioning error and slow convergence speed. To address the challenges of low sampling efficiency and particle impoverishment, a time sequence Monte Carlo localization algorithm based on particle swarm optimization (TSMCL-BPSO) is proposed in this paper. Firstly, the sampling region is constructed according to the overlap of the initial sampling region and the Monte Carlo sampling region. Then, particle swarm optimization (PSO) strategy is adopted to search the optimum position of the target node. The velocity of particle swarm is updated by adaptive step size and the particle impoverishment is improved by distributed estimation and particle replication, which avoids the local optimum caused by the premature convergence of particles. Experiment results indicate that the proposed algorithm improves the particle fitness, increases the particle searching efficiency, and meanwhile the lower positioning error can be obtained at the node\u27s maximum speed of 70ā€‰m/s

    Jahn-Teller distortion driven ferromagnetism in a perovskite fluoride monolayer

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    The Jahn-Teller distortion and the resulting orbital order usually cause some fascinating correlated electronic behaviors, and generally lead to antiferromagnetism in perovskite bulks. Here we demonstrate that the Jahn-Teller distortion present in the perovskite fluoride KCrF3_3 bulk can be retained to the two-dimensional limit, resulting in a staggered orbital order and ferromagnetism in the perovskite monolayer. Octahedral tilt and rotation distortion also appear in the ground-state structure of the perovskite monolayer, which have minor effects on the electronic and magnetic properties with respect to the Jahn-Teller distortion. In addition, in the prototype phase without structural distortion, the partial occupation of the ege_g orbitals leads to a ferromagnetic metallic state. This work facilitates the design of two-dimensional ferromagnets and functional properties based on Jahn-Teller distortion and orbital orderComment: 8 pages, 5 figures, 1 tabl

    Arabidopsis Putative Deacetylase AtSRT2 Regulates Basal Defense by Suppressing PAD4, EDS5 and SID2 Expression

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    The silent information regulator protein (Sir2) and its homologs are NAD+-dependent deacetylase enzymes that play important roles in a variety of physiological processes. However, the functions of the Sir2 family in plants are poorly understood. Here, we report that Arabidopsis AtSRT2, a homolog of yeast Sir2, negatively regulates plant basal defense against the pathogen Pseudomonas syringae pv. tomato DC3000 (PstDC3000). In response to PstDC3000 infection, the expression of AtSRT2 was down-regulated in a salicylic acid (SA)-independent manner. In addition, knock-out of AtSRT2 (srt2) enhanced resistance against PstDC3000 and increased expression of pathogenesis-related gene 1 (PR1). Conversely, overexpression of AtSRT2 resulted in hypersusceptibility to PstDC3000 and impaired PR1 induction. Consistent with this phenotype, expression of PAD4, EDS5 and SID2, three essential genes in the SA biosynthesis pathway, were increased in the srt2 mutant and decreased in AtSRT2-overexpressing plants. Taken together, these results demonstrate that AtSRT2 is a negative regulator of basal defense, possibly by suppressing SA biosynthesis

    Endoscopic rhizotomy for chronic lumbar zygapophysial joint pain.

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    BACKGROUND: Chronic lumbar zygapophysial joint pain is a common cause of chronic low back pain. Percutaneous radiofrequency ablation (RFA) is one of the effective management options; however, the results from the traditional RFA need to be improved in certain cases. The aim of this study is to investigate the effect of percutaneous radiofrequency ablation under endoscopic guidance (ERFA) for chronic low back pain secondary to facet joint arthritis. METHODS: This is a prospective study enrolled 60 patients. The cases were randomized into two groups: 30 patients in the control group underwent traditional percutaneous radiofrequency ablation, others underwent ERFA. The lumbar visual analog scale (VAS), MacNab score, and postoperative complications were used to evaluate the outcomes. All outcome assessments were performed at postoperative 1ā€‰day, 1ā€‰month, 3ā€‰months, 6ā€‰months, and 12ā€‰months. RESULTS: There was no difference between the two groups in preoperative VAS (P \u3e 0.05). VAS scores, except the postoperative first day, in all other postoperative time points were significantly lower than preoperative values each in both groups (P \u3c 0.05). There was no significant difference between the two groups in VAS at 1ā€‰day, 1ā€‰month, and 3ā€‰months after surgery (P \u3e 0.05). However, the EFRA demonstrated significant benefits at the time points of 3ā€‰months and 6ā€‰months (P \u3e 0.05). The MacNab scores of 1-year follow-up in the ERFA group were higher than that in the control group (P \u3c 0.05). The incidence of complications in the ERFA group was significantly less than that in the control group (P \u3c 0.05). CONCLUSIONS: ERFA may achieve more accurate and definite denervation on the nerves, which leads to longer lasting pain relief

    Concurrent administration of amiodarone and atenolol in the treatment of coronary artery disease complicated with arrhythmia, and its effect on serum levels of CD40L, TNF-Ī± and IL-6

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    Purpose: To investigate the efficacy of the combination of amiodarone and atenolol in the treatment of patients with coronary artery disease (CAD) complicated with arrhythmia, and its effect on serum levels of CD-40L, TNF-Ī± and IL-6.Methods: One hundred and twenty CAD patients with arrhythmia on admission in The First People'sHospital of Shuangliu District Chengdu, China were assigned to groups A and B, each having 60 patients. Amiodarone was administered to all the patients, while atenolol was additionally given to patients in group A. Levels of heart function indicators, inflammatory factors, blood pressure, heart rate, adverse reaction rate (ARR) and overall efficacy were evaluated for the two groups.Results: There were significantly improved levels of heart function indicators, and lower levels of CD40L, TNF-Ī± and IL-6 in group A, when compared with group B (p < 0.001). Moreover, treatment effectiveness was higher in group A than in group B (p < 0.05). However, there was no significant difference (p > 0.05) in ARR between groups A and B.Conclusion: The combined use of amiodarone and atenolol improves heart function indicators in patients with CAD and arrhythmia, reduces the levels of inflammatory factors, normalizes blood pressure and heart rate, and lowers ARR. However, further clinical trials on this combined therapy are required prior to its use in clinical practice

    Loop-mediated isothermal amplification for detection of porcine circovirus type 2

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    <p>Abstract</p> <p>Background</p> <p>Porcine circovirus type 2 (PCV2) is the primary causative agent of the emerging swine disease known as postweaning multisystemic wasting syndrome (PMWS). Nowadays, polymerase chain reaction (PCR) is still the most widespread technique in pathogen detection. Loop-mediated isothermal amplification (LAMP), a novel nucleic acid amplification method developed in 2000, will possibly replace PCR in the field of detection. To establish a LAMP method for rapid detection of PCV2, two pairs of primers were designed specially from the open reading frame 2 (ORF2) sequences of PCV2. A LAMP method for rapid detection of PCV2 was established. To compare with PCR, sensitivity and specificity of LAMP were evaluated using the optimized reaction system. The LAMP products could be determined by agarose gel electrophoresis or adding SYBR Green I dye.</p> <p>Results</p> <p>The amplification of LAMP could be obtained at 63Ā°C for 60 min. The detection limit was nearly 1 copy of DNA plasmid, more sensitive than PCR. There was no cross-reaction with porcine circovirus type 1 (PCV1), porcine pseudorabies virus (PRV) and porcine parvovirus (PPV) under the same conditions.</p> <p>Conclusions</p> <p>LAMP is an useful rapid detection method with high sensitivity and specificity for PCV2.</p
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