Numerical Simulation on the Influence of Bridge Construction on River Flood Control in a Bottleneck Reach

Bottleneck reach regions with narrow and deep cross sections prevent sediment transport and weaken flood control capacity. In addition, bridge constructions can exacerbate the risk of flooding in these areas. In this study, the Longhai Railway Extension Project at the Xianyang reach of the Weihe River in China was selected as a typical object. A horizontal 2-D numerical model was used to assess the effects of three engineering plans on flood discharge capacity under three flood frequencies. Plan 1 was designed to include building a new bridge, demolishing the three original bridges and dredging a single section of the channel. Plan 2 was the same as Plan 1, except for the compound sections. Plan 3 was designed with the four bridges coexisting and no dredging projects carried out. The results indicated that Plan 3 will increase the water level by 0.2-0.3 m in the upstream reach. The cross-sectional area was approximately 370 m2 larger under Plan 1 than under Plan 2. Water levels of 300-, 100-, and 5-year flooding around the bridge were reduced by 0.9, 0.9, and 0.6 m, respectively. To improve flood control capacity, an effective dredging project must be executed to widen the river and reduce the water stage in the bottleneck reach where the bridge is constructed

Behavioral Responses of Apis mellifera Adult Workers to Odors from Healthy Brood and Diseased Brood

Studies of adult workers’ responses to infected brood were undertaken to isolate discrete volatile compounds that elicited honeybee hygienic behavior. Using a freeze-killed brood assay, we determined that in healthy colonies adult workers recognized and emptied infected cells with a 95% clearance rate. SPME-GC-MS results emptied >95% infected cells indicated differences in the composition and relative content of volatile compounds released by healthy and diseased brood. Additionally, we determined that the main volatile compound released from the pathogen Ascosphaera apis was phenethyl alcohol. The Y-tube olfactometer indicated that 10- to 20-day-old workers of healthy colonies, but only 15-day-old workers of diseased colonies, were significantly sensitive to differences in characteristic volatile compounds. This information could facilitate honey bee selection based on mechanisms that contribute to chalkbrood disease tolerance

Mechanical properties and microscopic characteristics of steel fiber coal gangue concrete

Incorporation of coal gangue in the concrete mixes can realize utilization of the solid waste and reduce extraction/use of natural aggregates. To improve the mechanical properties of coal gangue concrete, this paper studies use of steel fibre together with coal gangue coarse aggregate, coal gangue fine aggregate/sand in various concrete mixes. The effect of volume dosages of steel fibre and different levels of replacing nature coarse aggregate and river sand with coal gangue aggregates on concrete compressive strength was first investigated. Then, a design of experiment using orthogonal test was adopted to study concrete mixes with 3 factors, namely, coal gangue coarse aggregate, coal gangue sand and steel fibre, and each at 3 levels. Through multidimensional statistical data analysis of the test results, the primary and secondary factors and the optimal composition of the steel fibre reinforced coal gangue concrete were identified, and a grey prediction model for compressive strength of the concrete mixes established. The microstructural characteristics and failure mechanism of steel fiber reinforced coal gangue concrete was also studied and discussed

Single-feature polymorphism discovery by computing probe affinity shape powers

<p>Abstract</p> <p>Background</p> <p>Single-feature polymorphism (SFP) discovery is a rapid and cost-effective approach to identify DNA polymorphisms. However, high false positive rates and/or low sensitivity are prevalent in previously described SFP detection methods. This work presents a new computing method for SFP discovery.</p> <p>Results</p> <p>The probe affinity differences and affinity shape powers formed by the neighboring probes in each probe set were computed into SFP weight scores. This method was validated by known sequence information and was comprehensively compared with previously-reported methods using the same datasets. A web application using this algorithm has been implemented for SFP detection. Using this method, we identified 364 SFPs in a barley near-isogenic line pair carrying either the wild type or the mutant <it>uniculm2 </it>(<it>cul2</it>) allele. Most of the SFP polymorphisms were identified on chromosome 6H in the vicinity of the <it>Cul2 </it>locus.</p> <p>Conclusion</p> <p>This SFP discovery method exhibits better performance in specificity and sensitivity over previously-reported methods. It can be used for other organisms for which GeneChip technology is available. The web-based tool will facilitate SFP discovery. The 364 SFPs discovered in a barley near-isogenic line pair provide a set of genetic markers for fine mapping and future map-based cloning of the <it>Cul2 </it>locus.</p

Thermodynamics of the iron-rich portion of the Fe-C-Zn system: 1473-1873 K

To understand the high-temperature thermodynamics of the iron-carbon-zinc system, the solubilities of zinc in iron/iron-carbon alloys have been measured by equilibrating zinc vapor with iron/iron-carbon samples, in the temperature range of 1473 K to 1873 K. The carbon composition was varied from 0 to 4.6 wt.%. The calculated zinc activities deviated positively from ideality. Zinc obeys Henrian behavior in liquid iron/iron-carbon alloys at PZn ≤ 1 atm. Generally, the solubility of zinc decreased with increasing temperature and carbon content. Based on experimental data, thermodynamic modeling of the iron-carbon-zinc system was performed in both liquid and solid solutions.... The equilibrium partition coefficient of zinc between the δ-ferrite and liquid regions of the iron-carbon phase diagram was calculated on the basis of the above two equations and estimated from experimental data for zinc between the austenite and liquid regions. Based on the present work, no significant segregation is expected during equilibrium solidification --Abstract, page iii

Thermodynamics of the Iron-Carbon-Zinc System

A two-zone isopiestic experimental technique was used to determine the solubility of zinc vapor in liquid and solid iron-carbon alloys as a function of zinc partial pressure (0.1 to 1 atm), carbon content (0 to 4.6 wt Pct), and temperature (1473 to 1873 K). The solubility of zinc at a given partial pressure decreases with both increasing temperature and carbon content in both liquid alloys and solid austenite; its activity in these solutions, and in pure δ-ferrite, deviates more positively from ideality than previous model-based predictions have suggested. The Bale-Pelton unified interaction parameter formalism was successfully applied to the results of liquid-alloy experiments, but the degree of experimental scatter in the austenite equilibrations was too great to allow its application in the calculation of solid-solution iron-carbon-zinc thermodynamic parameters. Using the available results, values were calculated for the equilibrium partition coefficient Kzn in solidifying iron-carbon alloys as a function of alloy carbon content; the results suggest that significant segregation of zinc between solid and liquid phases is not likely. © 1994 The Minerals, Metals & Material Society

CBED Tools for semi-automatic measurement of crystal thicknesses

Convergent-beam electron diffraction (CBED) is one of the most popular techniques to measure crystal thickness. The traditional measurement involves linear fitting of several fringes across the CBED disc, but for a thin crystal with fewer than three fringes the usefulness of this method will be limited. CBED Tools, a free plugin for the DigitalMicrograph software, provides a fast (similar to 12 min) and accurate algorithm to measure the crystal thickness on the basis of the linear fitting method, but it is also capable of determining the crystal thickness when it is very thin and only one fringe or part of the first fringe is recorded. CBED Tools can also be utilized to handle the severely distorted CBED pattern obtained when the zero-order Laue zone Kikuchi lines overlap with the fringes.</p

Linear Impulsive System Optimization using Adaptive Dynamic Programming

This paper investigates the optimal control problem for linear impulsive systems with impulsive moments fixed. Based on adaptive dynamic programming(ADP), a numerical method is proposed to iteratively solve for this optimal impulsive control. The temporal difference of the value functions is used to determine whether the optimality has been achieved. A gradient based optimization is carried on to update the controller; The optimality principle is used to update the value function. When the optimality has been achieved, the controller output converges to the optimal impulsive control satisfying the optimality conditions. The convergence proof of this impulsive ADP algorithm is presented. Results of a scalar and a multi-variable linear impulsive systems are given in the simulation section for illustrative purpose. © 2012 IEEE