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Xylongoic acids A–C, three isopimarane diterpene derivatives were isolated from the rice cultures of Xylaria longipes HFG1018, a fungicolous fungus isolated from the fruiting bodies of the wood-decay and medicinal fungus Fomitopsis betulina. The structures of the isolated compounds were determined by extensive analysis of NMR and HRESIMS data.

In this paper the characteristics of CFRP reinforcement on the improvement of the fatigue strength of aluminium alloy plates with fastener holes are investigated. The CFRP reinforcement schemes including the number of laminate layers, single-sided and double-sided strengthening are taken into account. Fatigue tests with constant loading amplitude were conducted to compare different failure mechanisms involved with such structural details. The stiffness degradation of test specimen failed by interfacial debonding is shown to be relatively gradual prior to plate rupture while the propagation of the fatigue crack at the transition of the punching surface appears to be retarded to some extent due to the tensile strengthening of the carbon fibre. The contributions of carbon fibre and adhesive interface to the strength improvement are quantified. Discussions are also made for the fatigue life of similar details with some other hole forming methods reported in the literature. Recommendations are given for the assessment of the fatigue life of CFRP reinforced specimens studied herein with appropriate detail classes codified in the BS8118 standard. Finally, a new formula allowing for the contributions of the plate and carbon fibre in tension, the adhesive interface in shear and additional secondary bending effect is proposed in the evaluation of the improvement fatigue endurance. The proposed formula is verified from a good correlation with finite element analytical results and from original test data with a notable reduction of scatters. Its application scope is also discussed.

The present paper deals with the shear buckling response of trapezoidal profiled webs in girders with concrete-filled rectangular hollow section (RHS) flanges. It outlines an experimental work of four girders with shear buckled trapezoidal profiled webs in interactive and global manners. Characteristic strain distributions on the trapezoidal profiled webs are reported. The analysis of load-deformation responses indicates that the trapezoidal profiled web buckled in the global manner suffered greater strength drops at early stage and less strength improvement contributed by the concrete-filled RHS flange in contrast to those buckled in interactive manner with partial local buckling. Finite element models explicitly allowing for isolated trapezoidal profiled webs with varied side boundaries and visual girder models with proposed design ratios are then presented for 572 cases. It is shown that the first eigenmode shape and critical stressing of the trapezoidal profiled webs are most likely influenced when the shear buckling in local manner takes place. Related geometric ratios involved with shear span, web slenderness, trapezoid altitude and subpanel height are examined through a parametric study. Afterwards, an analytical formula incorporating a proposed rigidity ratio as well as a correlated contribution coefficient is proposed for the determining shear buckling strength of trapezoidal profiled webs in the girders with concrete-filled RHS flanges. The proposed formula is verified in contrast to referred ones through a comparative study which can be deemed suitable for the design of trapezoidal profiled webs in girders with concrete-filled rectangular hollow section (RHS) flanges.

This paper outlines an experimental study on the shear behaviour of structural silicone adhesively bonded steel-glass orthogonal lap joints. In the combination of steel plate and glass panel to for...

Cracking of concrete is one of the critical parameters for the structural safety evaluation of building components after high-temperature exposure. In this paper, a method was developed to detect the cracks of concrete after exposure to high temperature. The gray-scale images of the cross-sections of concrete were binarized with a local-binarization algorithm, and then the isolate cracks were extracted to analyze the geometric attributes, including length, average width, and area. The factor of circle of each isolate crack was used to filter the noise and fake cracks. The proposed method was applied to the real images of both cross-sections and surfaces of high-temperature-damaged concrete to test the effectiveness. Moreover, based on the detection results, the effects of four parameters, i.e. local window size (Sw), step size (Sstep), local threshold ratio (Rt) and upper limit of factor of circle (Fc,lmt), in the proposed method were discussed to decide the optimal option. The results indicate that with the optimal parameters (Sw = 10 pixels, Sstep = 0.5, Rt = 0.85 for cross-sections and 0.95 for surface, Fc,lmt = 0.3), the proposed method can detect the cracks on both the surface and cross-section of concrete effectively. Some unclear cracks which were not detected with the optimal parameters can be detected out by combining the results from different groups of parameters.

Steel-glass composite beams with the combination of glass webs and steel flanges are known to be able to attain good ductility in contrast to pure glass panels. As a concentrated load is introduced away from the middle of the beam span, its resultant stress concentration can induce shear compression failure on the glass web which is distinguished itself from flexure failure as reported in the literature. This paper presents an experimental study on the in-plane shear compression behaviour of composite beams with laminated glass webs. Distinct failure mode related to load induced edge delamination traces on the glass web is reported. Based on the test results, the distribution of acting strains and stresses within the composite beams is plotted. The formation of inclined cracks on the glass web is justified as the stress trajectories are prone to bend to form a diagonal tension stress state. It is shown from the response of composite beams that the strength and elastic stiffness of composite beams are improved when the adhesives with better mechanical properties are used. Afterwards, it is shown that the strengths of test specimens are greater than these of counterpart glass stabilizing fins or stiffening fins due to the flexibility of adhesive joining. Finally, the test strengths have been evaluated based on the edge delamination traces and the equilibrium of the energy dissipation of proposed mechanism. It is demonstrated that the proposed mechanism in contrast to referred formulae is able to give a better prediction of strength.

Objective: To explore the changes of MCP-1, FKN, and related cytokines in the serum and cerebrospinal fluid (CSF) in children with epidemic encephalitis B. Methods: A total of 40 children with epidemic encephalitis B who were admitted in our hospital from June, 2014 to June, 2017 were included in the study and divided into the severe group (n=15) and general group (n=25) according to the severity group. Moreover, 20 children who were suffered from oblique inguinal hernia, perineal adhesion, and cryptorchidism were served as the control group. The serum and CSF specimens were collected 24 h after admission and during the recovery period in children with epidemic encephalitis B. The serum specimen was collected 24 h after admission in the control group, and CSF specimen was collected during the lumbar puncture. ELISA was used to detect CMP-1, FKN, IL-1β, IL-18, and TNF-α levels in the serum and CSF. CMP-1, FKN, IL-1β, IL-18, and TNF-α levels in children with epidemic encephalitis B on the day after admission and 2-3 weeks after admission and in the control group were compared. The changes of CMP-1, FKN, IL-1β, IL-18, and TNF-α in children with severe and general epidemic encephalitis B were observed. Results: CMP-1 and FKN levels in the serum and CSF in children with epidemic encephalitis B in the critical stage were significantly higher than those in the recovery stage and in the control group. The serum CMP-1 and FKN levels in children with epidemic encephalitis B during the recovery stage were not significantly different from those in the control group, while CMP-1 and FKN levels in CSF were significantly higher than those in the control group. CMP-1 and FKN levels in the serum and CSF in children with severe epidemic encephalitis B were significantly higher than those in the general group. IL-1β, TNF-α, and IL-18 levels in the serum and CSF in children with epidemic encephalitis B during the critical stage were significantly higher than those during the recovery stage and in the control group. IL-1β, TNF-α, and IL-18 levels in the serum and CSF in children with epidemic encephalitis B during the recovery stage were significantly higher than those in the control group. IL-1β, TNF-α, and IL-18 levels in the serum and CSF in children with severe epidemic encephalitis B were significantly higher than those in the general group. Conclusions: CMP-1, FKN, IL-1β, TNF-α, and IL-18 levels in the serum and CSF in children with epidemic encephalitis B are correlated with the severity degree, detection of which can contribute to estimate the clinical typing and condition change of epidemic encephalitis.

Post-fire-curing is an effective method to recover fire-damaged concrete. In order to investigate the effects of cement dosage and cooling regimes on the recovery of fire-damaged concrete, three kinds of concrete specimens, with different cement dosages of 412, 392, 372 kg/m3, were prepared and tested. After cooling either in a furnace or ambient environment to the room temperature, these specimens were first soaked in water for 24 h and then subjected to 29 days’ post-fire-curing. Based on temperature history, residual compressive strength and cracks in the cross sections were tested and analyzed. And scanning electronic microscope (SEM) was used to help the morphology analysis. A new parameter named heat accumulation factor was proposed to estimate the strength loss and the recovery potency of the fire-damaged concrete. It was known from the experiments that the difference of relative residual compressive strength of specimens with three cement dosages is less than 3 percentage points. After post-fire-curing, the relative residual compressive strength of the specimens cooled in the air recovered from 77% to 83%, while that of the specimens cooled in the furnace recovered from 65% to 87%. The longer exposure under high-temperature due to the cooling in the furnace was responsible for the lower relative residual compressive strength and higher recovered strength. This is because the high temperature can promote dehydration processes, accompanied with more rehydration products with a denser microstructure. The crack lengths were observed much longer in the specimens cooled in the ambient environment due to the higher temperature gradient during the cooling process. The higher temperature and temperature gradient near the surface can result in more intensive cracks.

This study focuses on the pullout behaviour of composite structures having closed shape geometry Perfobond Leiste (PBL) shear connectors wrapped with carbon fibre reinforced polymer (CFRP). Eight test specimens having PBL connectors with and without CFRP were used to perform the pullout tests. These tests were performed under static loading, and the concrete thickness and the embedment depth were the parameters used to evaluate the effects of CFRP jacketing on the pullout strength. The responses, that is, the initial cracking load, the ultimate pullout capacity and the displacement, were investigated. Failure modes were analysed, and a new model was proposed because of the unavailability of suitable models for PBL shear connectors with CFRP. The diagonally bonded CFRP jackets significantly delayed the onset of cracking and showed superior performance in terms of deformation capacity and ultimate pullout strength. A strength model was proposed to predict the ultimate pullout capacity of CFRP-confined PBL composite dowels. Overall, the study demonstrated that it is more efficient to use the proposed CFRP-confined PBL shear connectors than other connectors in practical engineering applications, given the improved deformation capacity and the ultimate shear strength.

BackgroundInhibition of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) pathway improves the neurological outcome in the transient middle cerebral artery occlusion (tMCAO) animal model. In this study we analyzed the microRNAs profile targeting NOX2 and NOX4 genes and its response to NOX2/4 inhibitor VAS2870 to understand the mechanisms of this protective effect.MethodsThe intraluminal filament tMCAO model was established in hyperglycemic rats (n=106) with 5 hours ischemia followed by 19 hours reperfusion. NOX inhibitor VAS2870 was delivered intravenously before reperfusion. Infarct volume, hemorrhagic transformation, and mortality were determined at 24 hours after cerebral ischemia. MicroRNAs profile targeting NOX2 and NOX4 genes were predicted by microRNA databases and further evaluated by microRNA microarray and quantitative RT-PCR.ResultsTen microRNAs potentially targeting NOX2 and NOX4 genes (including microRNA-29a, microRNA-29c, microRNA-126a, microRNA-132, microRNA-136, microRNA-138, microRNA-139, microRNA-153, microRNA-337, and microRNA-376a) were significantly downregulated in the ischemic hemisphere in the tMCAO group compared with the sham-operated group, as shown by microRNA microarray and quantitative RT-PCR (all pConclusionsSeveral microRNAs potentially targeting NOX2 and NOX4 genes displayed altered levels in hyperglycemic rats with the tMCAO model, suggesting their regulatory roles and targeting potentials for acute ischemic stroke treatment. Targeting specific microRNAs may represent a novel intervention opportunity to improve outcome and reduce hemorrhagic transformation after mechanical reperfusion for acute ischemic stroke.

Conventional chemotherapy for leukemia inevitably causes systemic toxicity. Acanthopanax senticosus, a naturally occurring herb used in traditional Chinese medicine, has been found to be a multipotent bioflavonoid with great potential in the prevention and treatment of malignant diseases. However, the mechanism underlying the action of A. senticosus in epigenetic regulation is poorly understood. In the study described here, we focused on the efficacy of A. senticosus in inducing apoptosis of leukemia cells and a possible mechanism. By evaluating the inhibition ratio and morphologic changes, we found that A. senticosus can inhibit growth and induce apoptosis of human leukemia HL-60 and HL60/ADM cells in a dose- and time-dependent manner. Furthermore, A. senticosus induced Fas ligand (FasL) expression and blocked the cell cycle in S phase. In addition, A. senticosus exhibited a potential for inhibition of histone deacetylase (HADC), which contributes to histone acetylation. It possibly resulted in the promotion of the expression of FasL. It is suggested that A. senticosus could be recognized as a new HDAC inhibitor which was able to reactivate aberrantly silenced genes. We discuss the clinical aspects of using A. senticosus for treatment of leukemia.

This paper evaluates the yield and ultimate strengths of a blind bolted endplate to square tubular column connection in joint tensile region. It outlines a research work of eleven connection tests with focus on the strengths of the connection components under tensile loads. The influences of the bolt gauge width, slenderness of tubular columns and bolt size details on the strengths of the connections in three failure modes are reported. Based on the experimental test results, yield strength determination methods are examined and discussed on the basis of deformations of the tube connecting face and the overall connection. Finite element models explicitly allowing for the configuration details of the Hollo-Bolt are then presented and compared with the test results. Subsequently, an analytical model is proposed for the prediction of yield strength with due consideration given to the plastification of SHS column and combined action of the blind bolt related to three failure modes. Based on an augmented consideration of membrane effect and circumferential locking action of the Hollo-Bolt, the analytical model is also extended for the prediction of ultimate strength. Additionally, two geometric parameters in characterizing the failure modes of the connection are discussed from a numerical parametric study. The analytical results presented in this paper provide some essential information for the strength design recommendations of such a blind bolted endplate connection to square tubular column.

Characterization of the low cycle fatigue response of the connection dominated by the hollow structural section (HSS) column in flexural bending and the bolt in tension are necessary to the design of its constitutional semi-rigid joints under earthquake scenarios. This paper presents the results of an experimental programme to evaluate the low cycle fatigue related characteristics of bolted connections to HSS columns. A summary of a total of 69 tension tests of T-stub connections is reported. The geometric parameters were varied as the bolt gauge width, the tube wall slenderness, the bolt size and the tube sidewall depth. Based on the experimental test results, the typical failure mechanisms, the hysteretic load-deformation relation and the response characteristics such as degradations of strength and energy dissipation capacity of the connections are examined. It is shown that the bolt gauge width and the tube wall slenderness have significant influences on the failure mode, the tensile capacity and stiffness which prompt two design parameters; namely, bolt gauge width to tube width ratio (β) and the tube wall thickness-to-half wall width ratio (Ψ0), in quantifying most influential geometric details of the connection. Moreover, the low cyclic fatigue life test results are compared with the codified S–N curves through a transformation of displacement range into effective stress range. It demonstrated a better contrast with test results by further allowing for the geometric parameters of β and Ψ0. Finally, the damage model analysis is employed to study the deterioration progress of the test connections through a comparison with typical damage indices available in the literature. The deficiencies of referred index are identified thereby promoting the proposal of a new model incorporating the stiffness and the energy dissipation in the representation of damage under constant amplitude loading condition. It is shown that the proposed model can give a reasonably well prediction of experimental evidences.

A 27-year-old woman underwent antenatal ultrasonography at 32 weeks of gestation, and the fetus was noted to have two cystic lesions within the pelvis, suggesting bilateral ovarian cysts. The right-sided lesion measured 2.1 cm and the left 3.0 cm in diameter. They were anechoic with well-defined margin and one septation within the left-sided lesion, which was assumed to have a high likelihood of already having torted.1 Reassessment of the mass at 33 weeks’ gestation noted that size of the right-sided lesion increased to 4 cm, while the …

The top 10 most influential articles in Very high cycle fatigue (VHCF) have been indentified from web of science data. The attributes of the top 10 papers have been discussed. It was found that specialty area of fatigue called as “VHCF” is an emerging field. The most cited papers discussed the two the fatigue crack mechanism in fatigue. It was found that crack initiation shifts from surface to subsurface if the material beyond 107 cycles. There are some models which can predict the fatigue life of the material however the exact estimation is still challenging. Hence, it was found that still further efforts are required in the field to accurately understand the VHCF behavior.

Geopolymeric recycled concrete (GRC) is a new construction material which takes environmental sustainability into account. In this paper, an experimental study was carried on 12 concrete filled steel tubular columns under axial loading, in order to fill a knowledge gap on the engineering and structural properties of GRC filled steel tube (GRCFST). Two section sizes of square hollow sections filled with GRC and recycled aggregate concrete (RAC) respectively, with different recycled aggregate (RA) replacement ratios of 0%, 50% and 100%, were used in the experiments. The test results indicated that the ultimate strength was reduced when adding more RAs in the columns, while the peak strain increased. The ductility of the columns was improved by increasing the RA replacement ratio. Overall, the influence of RA on the strength and ductility of GRCFST columns is greater than that of RAC filled steel tubular (RACFST) columns. The assumed theoretical model for predicting load versus deformation relation of GRCFST columns under axial loading was examined, and a revised theoretical model proposed. The results of the new model show good correlation with the experimental results.

According to the confusion effect of processing route drawing, few sampling points and contradiction between timing accuracy and system fluency of Windows system in high-speed CNC real-time plotting process, this paper presents a method based on Windows environment to achieve real-time plotting goal of the machining contour in high-speed CNC laser cutting process by pretreating G codes and interpolation algorithm improvement. Experimental research was implemented and this method has already been successfully applied to practical production. Comparing to traditional real-time plotting method, this method can not only achieve faster real-time plotting, but also ensure accurate graphic drawing quality and meet the demand of practical circumstances. This method, put forward by the author in addressing real-time plotting problem of laser cutting, can be equally applied to other two-dimensional high-speed cutting occasions.

This paper presents an analytical approach for the fatigue assessment of welds joining corrugated plates to flange plates. The failure mode, stress distribution and fatigue strength of such welded joints have been examined through experimental tests and finite element analyses. As the stress concentration at the external weld line of the transition curvature is very critical for the fatigue life assessment, the study of such geometric effect has been performed and its resultant stress characteristics are discussed. The results show that, for the stress concentration at the fatigue critical point of the transition curvature, the influence of the corrugation/curvature angle is more significant when the ratio of the curvature radius to the corrugation depth is smaller, and vice-versa. The S–N curve of referred cruciform joint details can be regarded as the lower bound in contrast to the fatigue strength of welded joints with varying corrugation angle. Allowing for the combined stress condition, the proposed analytical approach is demonstrated to be appropriate for the fatigue assessment of the welded joint with the corrugated plate. The consideration of residual stress in the proposed analytical model is also discussed in theory.

This paper puts forward a new type of gear anti-backlash drive mechanism, in view of traditional’ manufacturing is difficult and production cost is high. This mechanism uses the structure of a pair of worm gears which are against each other and double gears to eliminate the back clearance volume. The dynamic model of the mechanism in this paper is established by the method of lumped mass, and the model’s numerical solution is solved by fourth-order Runge-Kutta. Then the nonlinear dynamic characteristics of system are simulated and analyzed. The studies show that this mechanism whose backlash has been eliminated has a good dynamic characteristics, and increasing system’s meshing damping can shorten the vibration attenuation time and improving the average meshing stiffness can reduce vibration amplitude of the system.

Slender trapezoidal corrugated web does generally possess notable post-buckling capacity with certain reserve of shear resistance. Repeated secondary bending stresses due to post-buckling at the boundaries of the subpanel of the trapezoidal corrugated web, however, may result in potential local fatigue failure. A series of fatigue experimental tests on the slender profiled web girders with stiff flanges subjected to the action of predominant shear is outlined. The fatigue test results are presented in terms of stiffness deterioration and fatigue failure induced by out-of-plane deflection as the applied load exceeds the elastic critical load. It was found that fatigue cracks due to predominant shear action propagate much faster than these due to combined shear and tearing. Recommendations are prescribed for evaluating the fatigue resistance of post-buckled slender trapezoidal corrugated webs with appropriate detail categories codified in the Eurocode 3. Previously published analytical models correlating normalized shear resistances with relative plate slenderness ratios are compared against test data and discussed for their applicability. Based on the test results, a new mathematical representation is derived based on von Karman’s effective width concept for ultimate loads. The derived formula is demonstrated to correlate well with test data since reasonable allowances are given for the tension field theory and geometric characteristics of the trapezoidal corrugated webs.

NO in flue gas was oxidized into NO 2 by ozone in gas-phase first, and then SO 2 and NO 2 were oxidized by redox reaction between MnO 2 and SO 2 /NO 2 and catalyzed oxidation between O 2 and SO 2 /NO 2 in absorption process. Molar ratio of O 2 /(SO 2 + 0.5NO x ) in flue gas had a decisive effect on catalyzed oxidation in absorption process, and eventually influenced reaction byproducts, Mn extraction rate and SO 2 /NO x absorption capability. Results showed that increasing O 2 /(SO 2 + 0.5NO x ) enhanced catalyzed oxidation and led to the lower reaction pH. When O 2 /(SO 2 + 0.5NO x ) ⩽ 18, SO 2 and NO x were mainly oxidized by MnO 2 with main products of MnSO 4 and Mn(NO 3 ) 2 , while when O 2 /(SO 2 + 0.5NO x ) ⩾ 18, SO 2 and NO x were mainly oxidized by O 2 with main products of H 2 SO 4 and HNO 3 . Total absorption capability of SO 2 and NO x increased with increasing O 2 /(SO 2 + 0.5NO x ). Mn extraction rate increased with the increase of O 2 /(SO 2 + 0.5NO x ) first and then decreased, the maximum Mn extraction rate of 91% was got when O 2 /(SO 2 + 0.5NO x ) at around 13. Both the SO 2 /NO x absorption capability and Mn extraction rate could be enhanced by adding rhodochrosite as pH regulator in the case of O 2 /(SO 2 + 0.5NO x ) ⩾ 18.

A lab-scale circulation process of electrolytic manganese production with low-grade pyrolusite leaching by SO2 was introduced, exploring its feasibility and stability. Material balances of manganese and sulfur in circulation process were investigated. Results showed that the circulation process was entirely feasible. SO2 absorption efficiency of 99.66% and Mn extraction rate of 95.5% were obtained when a two-stage continuous countercurrent leaching process was used. The electrolytic manganese, meeting the needs of national industry grade standards, could be produced using purified leaching solution. 32 days' continuous running test proved good stability of the circulation process with the current efficiency of 78.1%, electricity consumption of 5396 kW h/t and total Mn recovery rate of 81.77%. The circulation process realized that the electrolytic manganese production with low-grade pyrolusite, has a wide prospect in industrial applications due to the advantages of stable performance, high efficiency and low consumption.

BackgroundSevere hemorrhagic transformation (HT) after mechanical thrombectomy predicts a poor clinical outcome in acute ischemic stroke. To better understand the mechanism of HT, we investigated the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) in HT after reperfusion during acute stroke and whether NOX2/4 inhibitor VAS2870 reduces reperfusion-induced HT after mechanical recanalization.MethodsA model of reperfusion-induced HT was established in rats (n=182) with hyperglycemic challenge and 5 h middle cerebral artery occlusion followed by 19 h reperfusion. NOX inhibitor VAS2870 was delivered intravenously 30 min before reperfusion. Infarct volume, brain water content, HT, neurological score, mortality rate, blood–brain barrier (BBB) damage, neuronal apoptosis, and reactive oxygen species were determined at 24 h after cerebral ischemia. The expressions of NOX1, NOX2, NOX4, and BBB-associated proteins were measured.ResultsNOX2 and NOX4 upregulation and severe HT were observed in hyperglycemic rats after cerebral ischemia/reperfusion. VAS2870 suppressed oxidative stress, neuronal apoptosis, and NOX2/4 upregulation in the ischemic hemisphere. VAS2870 reduced infarct volume (17.2±5.3% vs 37.4±9.2%, pConclusionsNOX2 and NOX4 may mediate HT in rats with large vessel stroke after mechanical reperfusion. Infusion of NOX inhibitor VAS2870 before mechanical thrombectomy represents a novel adjunctive therapeutic strategy to prevent reperfusion-induced HT and improve outcome of acute stroke treatment.

The governing equations for heat transfer and fluid flow are often formulated in a general form for the simplification of discretization and programming, which has achieved great success in thermal science and engineering. Based on the analysis of the popular general form of governing equations, we found that energy conservation cannot be guaranteed when specific heat capacity is not constant, which may lead to unreliable results. A new concept of generalized density is put forward, based on which a new general form of governing equations is proposed to guarantee energy conservation. A number of calculation examples have been employed to verify validation and feasibility.

Construction materials dominate the main responsibility to maintain the environmental sustainable development in human’s activities. Geopolymer concrete containing fly ash and recycled aggregate is a new concrete which can reuse the by-product of power station and waste concrete, as well as reduce the production of cement which contribute a lot of carbon dioxide emission in the manufacturing process. In this paper, experiments were carried out to investigate the mechanical properties and microstructure of geopolymer concrete with different recycled aggregate contents. Six mixtures were designed including alkali-activated fly ash geopolymeric recycled concrete and corresponding ordinary concrete as the comparison. The compressive strength of the concrete with 0%, 50% and 100% recycled aggregates was tested. The microstructure of these concrete were investigated by petrographic microscope under transmit light. According to experimental results, the strength development and failure mechanism are discussed. Furthermore, the application of such geopolymer concrete is discussed and suggested.

In this work, a unique electrode based on aminopropyl-triethoxysilane ( APTS)-coated porous silicon(PS) substrate has been fabricared and used as a urea-sensitive electrode after urease immobilization. PS substrate was formed by electrochemical anodization in an etching solution composed of HF and ethanol. APTS layer was formed on the PS surface by coating and heating at 1053K in argon atmosphere. Urease immobilization was carried out by immersing the APTS/PS in urease solution. The immobilized system gives linear response for concentrations of urea ranging in values between 3.6×10−3and 8.0×10−3mol dm-3, studied with voltammetry. The surface of biofunctionized porous silicon has thus provided a suitable environment for urease with 15 days retention of its activity. The molecular structure on the PS surface was characterized with infrared (IR) technique. The change in the surface morphology has been studied by scanning electron microscopy and it is observed that the immobilized system has successfully retained urease.

The low cycle fatigue tests on the crack initiation and propagation of cast magnesium alloys with two small holes were carried out by using in-situ scanning electron microscope (SEM) observation technology. The fatigue crack propagation behaviors and fatigue life, which are affected by two small artificial through holes, including the distances between two holes and their locations, were discussed in detail based on the experimental results and the finite element analysis (FEA). The results indicated that the fatigue multi-cracks occurred chiefly at the edges of two holes and the main crack propagation was along the weak dendrite boundary with the plastic deformation vestiges on the surface of &alpha, Mg phase of cast AM50 and AM60B alloys. The fatigue cracking characteristics of cast AZ91 alloy depended mainly on the brittle properties of &beta, Mg17Al12 phase, in which the multi-cracks occurred still at the edges of two holes and boundaries of &beta, Mg17Al12 phase. The fatigue crack initiation position of cast magnesium alloys depends strongly on the radius of curvature of through hole or stress concentration factor at the closed edges of two through holes. In addition, the fatigue multi-cracks were amalgamated for the samples with titled 45&deg, of two small holes of cast Mg-Al alloys when the hole distance is less than 4D (D is the diameter of the small hole).

This paper investigates the behaviour of the blind-bolt Hollobolt when used in moment-resisting connections. This is done through an investigation into its effects on the initial stiffness, strength and ductility of a T-stub connection. The T-stub connection is used to represent the tension zone of a moment-resisting connection. A theoretical model for the initial stiffness of such a connection has been proposed. The model is based on the stiffness of the bolted T-stub, as suggested by Eurocode 3, and also on the analytical model of a conical shell representing the flaring sleeves of the Hollobolt. Two 3D numerical models of the connection were developed using ANSYS. The first uses the Hollobolt as the fastener while the other uses the standard bolt. The numerical models were also used to study the clamping and the force transfer mechanisms, stiffness, strength and deformation capacity of the connections. The study included comparisons between the performance of the Hollobolt and the standard bolt. It is shown, using load–displacement curves, that the numerical analyses compare well with previously reported experimental results and with the proposed theoretical model. Parametric studies have been conducted to investigate the effects of the angle of flaring sleeve, bolt shank diameter and flange thickness on the connection behaviour. It has been found that the flange thickness mostly influences the strength and stiffness of the blind-bolted connection compared to the flaring sleeve angle and the bolt shank diameter.

Flashover in compartment fire itself is a catastrophe process. Its catastrophe behavior can be analyzed, and its topological function equation can also be set up by catastrophe theory. On the basis of analyzing swallowtail catastrophe characteristic, a flashover model of hot smoke layer, which is established based on energy conservation, is transformed in the dimensionless form firstly, and then diffeomorphism is applied to simplify it. By these transform, a catastrophe potential function is gained. The format of the catastrophe potential function makes it clear that this type of flashover belongs to swallowtail catastrophe. Subsequently, taking passenger carriage fire as an idiographic object, the connection between system control variable and burning condition is discussed. The results show that the space of catastrophe bifurcation in muster divide the fire into two section, namely flashover section and non-flashover section. If in flashover section, an unstable point can be obtained by using qualitative curve or differential coefficient curve of potential function. Furthermore, the temperature of hot smoke layer is calculated by the value of the critical point when flashover occurs. The calculation case of passenger carriage fire shows that the temperature of hot smoke layer is 625.3°C when flashover occurs in the carriage, which is agreement with real instance.

The importance of determining and understanding the very high cycle fatigue behaviors of materials has gained strength in recent years. Ti-alloys, in view of their high strength-to-weight ratio, have a range of structural applications. Of these, Ti-6Al-4V, belonging to the alpha-beta type is the most widely used. The present paper deals with investigations on the fatigue behavior of TC4, the Chinese equivalent to Ti-6Al-4V, up to very high cycles. Fatigue testing was carried out on a piezoelectric ultrasonic fatigue machine operating at 20 kHz frequency. Hourglass shaped resonant specimens were tested in ambient air at room temperature under completely reversed loading conditions (R = -1). Failure in the alloy was seen to occur right up to the gigacycle regime, with the fractures being found to initiate from the surface unlike in steels. The fracture surfaces exhibit brittle characteristics containing river patterns and cleavage facets, as well as striations.

Despite current advances in multimedia environments, tracing the geometrical structures of graphical images using force feedback remains an important research issue. In this paper, the development and implementation of a multi-modal display system (MMDs) for tracing 2D boundaries in graphic images are discussed. A method is proposed that provides a type of haptic feedback designed to assist a user to trace the contours of objects seen in images. This method is an example of a family of haptic synthesis methods whereby the force field explored by the user is dynamic in the sense that it depends both on movement as well as on the object being haptically represented. The proposed performance-based method provides users with a movement guidance through an active haptic sense rather than common impedance technique. The tracing effectiveness of the proposed method is verified experimentally.