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This paper investigates the post-fire seismic performance of steel reinforced concrete (SRC) beam to SRC column frames. Five SRC column to SRC beam planar frame specimens were tested in a program including a loaded fire test and a following horizontal cyclic loading test. Test parameters included heating time and column load ratio. The temperature development, deformation, post-fire hysteretic and skeleton curves, stiffness, ductility and damping coefficient of SRC frames are recorded, calculated and analyzed. The measured post-fire hysteretic curves indicates that the SRC frames exhibit very good energy dissipation capacity after fire exposure. The horizontal load capacity and viscous damping coefficient of SRC frames increase with the increase of column load ratio. However, column load ratio has an adverse influence on ductility as anticipated at normal temperature. One SRC frame specimen failed during the cooling phase, which demonstrates the importance of considering the cooling phase during the fire safety design.

This paper presents an experiment study of the post-fire behavior of five SRC columns under combination of axial eccentrical loading and fire. The experiment phenomena and mechanical response of the SRC column specimens during experiment, specifically loading, heating, cooling and post-fire loading were observed. The residual load bearing capacity, failure modes and vertical deformation were studied. With the test program, the effects of parameters such as the load ratio, the fire duration time and the steel ratio were studied. It is shown that the effects of temperature delay become more obvious with the increase of the depth from the heated surface. Some of the SRC column specimens failed during the cooling phase. For other specimens residual deformations were observed when the furnace temperature decreased to ambient temperature. The influence of some parameters including the load ratio, the fire duration time and the steel ratio on the post-fire load bearing capacities was discussed. It can be concluded that the residual load bearing capacity of the SRC columns decreases with the increase of the fire duration time and the load ratio, and increases with the increase of the steel ratio. Finally, a finite-element analysis model was developed to simulate the behavior of the tested SRC columns.

This paper presents numerical simulation of underwater shock wave propagation nearby complex rigid wall. The Ghost Fluid Method (GFM) for the treatment of complex rigid wall is developed. The theoretical analysis on the GFM-based algorithm and relevant numerical tests demonstrate that the GFM-based algorithm is first-order accurate as applied to complex rigid wall. A large number of challenging numerical tests show that the GFM-based algorithm is robust and quite simple in various practical problems. The numerical results on shock wave propagation in the vicinity of rigid wall are verified by comparing to exact solution and the results by body-fitted-grid method.

Accompanying the enforcement of strategy to develop western regions, transport and other infrastructures of western China expand substantially and long tunnel in karst zones increases dramatically. Geological hazard of water inrush and mud outburst often occur in the process of karst tunnel construction, which often lead to equipment destroyed and construction period bungled, even serious casualty and economic loss. The influence of large-scale concealed caverns with high pressurized water on top of tunnel on the stability of rock pillar between them is researched in this paper. According to the actual conditions, rock pillar is simplified into beam with both ends built-in. Utilizing the conception of classic structural mechanics, a model is developed to calculate the minimum thickness of rock pillar in order to evaluate its stability by use of the criteria of shear strength and tensile strength of rock pillar. As a example, the proposed model is applied to predict the stability of rock pillar between karst tunnel on Yi-wan rail line and concealed cave with high pressurized water, the result illuminates that this methods is feasible to supply basis for evaluating the stability of rock pillar during construction period of karst tunnel.

Because of the existence of high stress in the surrounding rock of deep roadway, the physical and mechanical properties of the surrounding rock to change, and the surrounding rock stress distribution is very different from the shallow, so the way of shallow roadway support is not suitable for deep roadway. Deep soft-rock roadway support is a complex systems engineering, it should consider the different geological conditions, roadway scope of application, construction technology conditions, construction period and the cost and other factors to determine the optimal combined support program, if the special geological conditions encountered in the construction, it should be timely to improve the supporting program to meet the construction safety and ensure the quality. This paper is based on the characteristics of deep roadway support, sums up the combined support form in the project, researches and analyzes the combined support technology, and explores how to use suitable combined support form in deep roadway.

A fire performance finite element (FE) model of space grid structures in fire and after fire is proposed, and deformation, stress redistribution, failure modes of grid structures are also studied. The result shows that tensile membrane action arises when the grid is loaded after fire, and the load bearing capacity after fire is reduced by fire damage.

In order to avoid the effect of driving blasting on the adjacent roadway in 858 mines, numerical analysis of seismic intention was carried out. Based on monitoring data, the parameters suitable for local were obtained by Sadov's formula, by which the relationship between the maximum single-stage charge and the width of protect rock pillar were offered. According to design requirements, and considering the effect of driving blasting on the adjacent roadway, the maximum single-stage charge of driving blasting is 43.99kg.

A heat transfer finite element model for the temperature analysis of space grid structures considering the conduction and protection thickness of the steel members in fire is proposed, and the temperature field of a typical grid structure is analyzed by using the proposed model. The results show that the proposed model is reasonable.

Based on model tests, the wave function expansion method was used to study scattering on the interaction of explosive stress waves and the underground chamber, and analyze the influence of the incident angle, frequency and diameter on blasting vibration velocity of underground chamber. It is obtained that when the cavern was under the plane waves of the vault, the radial vibration velocity of the vault is the largest among the four measured data, and it is the most intense vibrating place. When the incidence direction offsets from the vault to the horizontal direction on the left, the radial velocity facing burst are all larger than the radial velocity back of the burst. When the incident direction is on the dome, the tangential vibration velocity will increase first and then decrease from the vault to the side wall. When the incident direction is at the haunch, the tangential vibration velocity in the corner should be noticed. With increasing of the frequency, the radial vibration velocity and tangential vibration velocity increase accordingly. At the forward part of the burst, the larger the chamber diameter is, the bigger the radial and tangential velocities are. At the back side of the burst, the bigger the chamber diameter is, the smaller the radial and tangential vibration velocities are.

The anti-explosion effects and anchored mechanism of tunnels reinforced by bolts were studied by numerical analysis. Comparing with compression-stress curve of the experiments and numerical simulation on the same location of the vault, it indicates that the simulation results are reliable. By contrast the vault displacement of anchored tunnel and unlined tunnel, it can be found that the vault displacement of the tunnel is significantly reduced through the reinforcement with anchor bolts. By comparing the crack distribution of the anchor tunnel and unlined tunnel, it shows that cracks of unlined tunnel are significantly thicker and wider than that of the anchored tunnel, which indicates that the anti-explosion effects of anchor rods are better. It can be known that the anchored bolts supporting can take effect of reinforcement and anti-explosion according to the time-histories curve of the anchor-head.

Failure mechanism and fire resistance comparison of concrete-filled steel tube (CFST) frames, reinforced concrete (RC) frames and steel reinforced concrete (SRC) fames are proposed in this paper when their bearing capacity and rigidity at room temperature are similar. The result shows that the failure mode and failure mechanism of the 3 frame structures are much different, and the SRC frames have the maximum fire resistance.

Practical teaching is a very important practical instructional segment in the period of undergraduate course of geotechnical engineering. With the rapid development of higher education, the university with distinctive features is attracted more attention. Mining is our university feature, the Status and Problems of graduation fieldwork in geotechnical engineering are analyzed; the practical teaching experience in reform in recent years is introduced; the reforms on fieldwork methods, guidelines and practical content of the geotechnical engineering are made the bold attempt, and its using in the sessions of the graduation students proved that the idea of reform is correct, guidelines is accurate and measures is appropriate, and graduation fieldwork effect of geotechnical engineering as "mining" characteristics is improved.

An experimental study on the fire performance of reinforcing concrete beam-column joints under ISO834 standard temperature-time curve was carried out, and the main parameters including the load ratio of the beams and axial compression ratio of the columns were chosen to study the performance of the joints. The deformation, the explosive spalling of concrete, the fire resistance and the collapse mechanism of the joints in fire are observed carefully, and several conclusions are drawn in the end.

BackgroundInformation on polymorphic DNA in organelle genomes is essential for evolutionary and ecological studies. However, it is challenging to perform high-throughput investigations of chloroplast and mitochondrial DNA polymorphisms. In recent years, EcoTILLING stands out as one of the most universal, low-cost, and high-throughput reverse genetic methods, and the identification of natural genetic variants can provide much information about gene function, association mapping and linkage disequilibrium analysis and species evolution. Until now, no report exists on whether this method is applicable to organelle genomes and to what extent it can be used.Methodology/principal findingsTo address this problem, we adapted the CEL I-based heteroduplex cleavage strategy used in Targeting Induced Local Lesions in Genomes (TILLING) for the discovery of nucleotide polymorphisms in organelle genomes. To assess the applicability and accuracy of this technology, designated ORG-EcoTILLING, at different taxonomic levels, we sampled two sets of taxa representing accessions from the Brassicaceae with three chloroplast genes (accD, matK and rbcL) and one mitochondrial gene (atp6). The method successfully detected nine, six and one mutation sites in the accD, matK and rbcL genes, respectively, in 96 Brassica accessions. These mutations were confirmed by DNA sequencing, with 100% accuracy at both inter- and intraspecific levels. We also detected 44 putative mutations in accD in 91 accessions from 45 species and 29 genera of seven tribes. Compared with DNA sequencing results, the false negative rate was 36%. However, 17 SNPs detected in atp6 were completely identical to the sequencing results.Conclusions/significanceThese results suggest that ORG-EcoTILLING is a powerful and cost-effective alternative method for high-throughput genome-wide assessment of inter- and intraspecific chloroplast and mitochondrial DNA polymorphisms. It will play an important role in evolutionary and ecological biology studies, in identification of related genes associated with agronomic importance such as high yield and improved cytoplasmic quality, and for identifying mitochondrial point mutations responsible for diseases in humans and other animals.

To explore the influence of visual attention in visual evoked potential (VEP) examination.The pattern visual evoked potential (PVEP) and flash visual evoked potential (FVEP) were used to examine 110 normal subjects whose visual acuity or corrected visual acuity is in the range of 4.8-5.2, and age between 20 to 30 years old. In PVEP inspection, subjects were asked to watch with three ways, to stare at the central screen (at the same time count silently the number of alternating of black and white squares to improve the subjects' attention), to stare at the central screen at the same time thinking other things, to look sideways (the left eye stared at the left bottom corner of the screen or the right eye stared at the right one). In FVEP inspection, subjects were checked with eyes open and closed respectively. The latency and amplitude of P100 wave were recorded. The data were statistically analyzed by SPSS 13.0 software. RESULTS In PVEP inspection, the latency and amplitude of P100 wave were statistically different among three watching ways. In FVEP inspection, latency and amplitude of P100 wave were statistically different between eyes open and closed group.Although the visual evoked potential test is an objective electrophysiological visual function test, it is susceptible to the influence of various subjective factors such as visual attention. It should arise the attention of forensic experts.

Background Endoscopic sphincterotomy (ES) is a therapeutic technique developed as an advanced application of endoscopic retrograde cholangiopancreatography (ERCP). An important adverse event associated with this procedure is hemorrhage, which may sometimes be uncontrollable. We sought to examine whether cap-assisted hemoclip application is effective in controlling ES–induced hemorrhage. Methods In this prospective study, we investigated the outcomes in 10 patients who had uncontrolled ES–induced hemorrhage and were treated by cap-assisted application of hemoclip with a forward-viewing endoscope. Results Nine of the 10 investigated patients were successfully treated using the cap-assisted hemoclip technique with forward-viewing endoscope, yielding a success rate of 90 %. The patient with hemorrhage non-responsive to hemoclipping required catheter embolization of the bleeding artery after its identification by digital subtraction angiography. One of the 10 patients developed mild pancreatitis after the procedure, but was successfully managed conservatively. Conclusions Cap-assisted hemoclip application with a forward-viewing endoscope appears to be an effective therapeutic modality for achieving hemostasis in cases of ES–induced hemorrhage, without the occurrence of any severe adverse events; we believe that this method should be considered as an option in the management of ES–induced hemorrhage.