Shear Behavior of Screw Connection between Cold-Formed Steel and Gypsum Sheathing at Elevated Temperatures

The screw connections between cold-formed steel (CFS) and gypsum sheathing play an important role in the axial and lateral performance of CFS wall panels. Previous researches were mainly focus on the shear behavior of such screw connections at room temperature. This paper carried out a preliminary experimental investigation on the mechanical performance of screw connections with single layer gypsum sheathing at elevated temperatures. Limited to the cavity dimension of the furnace, the single-lap test of CFS coupon -fastener-sheathing connection was adopted and compared with the previous test results of sheathing-to-profile screw connections at room temperature. The failure of screw connections with single layer gypsum sheathing was identified as the breaking of the sheathing edge at elevated temperatures and a sharp decrease of the shear strength was observed beyond 150 °C. In addition, the load-displacement curves of screw connections were well predicted by an exponential model with the post-peak branch at elevated temperatures

Fire Resistance Prediction of Load Bearing Cold-Formed Steel Walls Lined with Gypsum Composite Panels

An innovative load-bearing cold-formed steel (CFS) wall lined with gypsum composite panels was developed with the goal of improving the construction efficiency and fire performance of these walls for applications in mid/high-rise buildings. The gypsum composite panel was formed by sandwiching insulation and plasterboard strips between two layers of gypsum plasterboards. Subsequently, the predicted fire resistance of these CFS walls was predicted based on our previously developed and experimentally validated modeling method. The degenerated material properties of the cold-formed steel and thermal physical property of the gypsum plasterboard and aluminum silicate wool were obtained from our pervious experimental investigations and used as the basic input parameters in the present fire resistance modeling. The results showed that the fire performance of the CFS walls lined with gypsum composite panels improved greatly. The configuration details and corresponding design load levels were also determined for the CFS walls with a fire resistant rating of 120 and 150 min

An experimental approach to quantify strain transfer efficiency of fibre bragg grating sensors to host structures

This paper developed a method to evaluate the strain transfer efficiency of fibre Bragg grating sensors to host structures. Various coatings were applied to fibre Bragg grating sensors after being fabricated. They were epoxy, silane agent and polypropylene, representing different surface properties. A neat epoxy resin plate was used as the host in which the coated fibre sensors were embedded in the central layer. The tensile strain output from the FBGs was compared with that obtained from electrical strain gauges which were attached on the surface of the specimen. A calculating method based on the measured strains was developed to quantify the strain transfer function of different surface coatings. The strain transfer coefficient obtained from the proposed method provided a direct indicator to evaluate the strain transfer efficiency of different coatings used on the FBG sensors, under either short or long-term loading. The results demonstrated that the fibre sensor without any coating possessed the best strain transfer, whereas, the worst strain transfer was created by polypropylene coating. Coatings play a most influential role in strain measurements using FBG sensors

2-{4-[(Quinolin-8-yl­oxy)meth­yl]phen­yl}benzonitrile

In the title compound, C23H16N2O, the bond angle at the O atom that connects the benzene ring and the quinoline ring system is 116.0 (2)°. The quinoline ring system make a dihedral angle of 16.5 (2)° with the adjacent benzene ring. The dihedral angle between the biphenyl benzene rings is 70.8 (2)°

DUNE: Improving Accuracy for Sketch-INT Network Measurement Systems

In-band Network Telemetry (INT) and sketching algorithms are two promising directions for measuring network traffics in real time. To combine sketch with INT and preserve their advantages, a representative approach is to use INT to send a switch sketch in small pieces (called sketchlets) to end-host for reconstructing an identical sketch. However, in this paper, we reveal that when naively selecting buckets to sketchlets, the end-host reconstructed sketch is inaccurate. To overcome this problem, we present DUNE, an innovative sketch-INT network measurement system. DUNE incorporates two key innovations: First, we design a novel scatter sketchlet that is more efficient in transferring measurement data by allowing a switch to select individual buckets to add to sketchlets; Second, we propose lightweight data structures for tracing "freshness" of the sketch buckets, and present algorithms for smartly selecting buckets that contain valuable measurement data to send to end-host. We theoretically prove the effectiveness of our proposed methods, and implement a prototype on commodity programmable switch. The results of extensive experiments driven by real-world traffics on DUNE suggest that our proposed system can substantially improve the measurement accuracy at a trivial cost.Comment: Technical report for the paper published in IEEE INFOCOM 202