T-shaped Connector Research Articles

Thermal protection properties of profiled timber with peat-vermiculite insulation

Today, the use of environmentally friendly materials is becoming increasingly important. The construction of energy-saving buildings with enclosing structures made of insulated profiled timber, is one of the most promising areas in low-rise construction.Materials having minimum negative impact on the environment during their operation, include new construction insulation materials based on peat-vermiculite granules. The paper studies the main physical properties of wooden exterior walls made of profiled timber, in which peat vermiculite is used as insulation, thermal conductivity of which ranges from 0.05 to 0.06 W/(m·K). For this purpose, numerical simulation is performed for the heat-mass transfer in wooden enclosing structures made of insulated timber with three different connector options.The temperature and heat flow distributions are obtained as a result of modeling stationary thermal conductivity processes in timber structures. It is shown that plywood connectors do not affect the thickness temperature distribution in wooden walls with peat-vermiculite insulation. An increase in thermal conductivity of insulation has no significant effect on the temperature difference along the connector axis or outside the region of its temperature influence.It is found that the thickness of the peat-vermiculite insulation layer should be at least 0.176 m to ensure the compliance with the main requirements for thermal protection properties of enclosing structures in the climatic conditions of Tomsk. The greatest heat loss with a minimum insulation thickness is observed for the wall made of profiled insulated timber with T-shaped connectors. A high-strength timber with the additional central lamella has the best thermal protection with the lowest insulation thickness.

Seismic behavior of steel frames with H-shaped damper

This paper investigates the effect of dampers on the seismic performance of steel frames with unequal depth beam-column (UDBC) joints. First of all, the finite element (FE) models of the UDBC joint and steel frame were regenerated by ABAQUS and verified by experimental results. Secondly, the design method for three H-shaped dampers with different web perforation forms (vertical, elliptical, and diamond) was provided. Finally, five steel frames were built using ABAQUS, and pushover analysis and dynamic time-history analysis were performed on them. The results indicated that dampers could decrease the maximum vertex displacement and inter-story shift angle of steel frames with UDBC joints under three seismic waves by 4.47% to 17.17% and 7.71% to 23.88%. The effect of H-shaped dampers was similar to that of T-shaped connectors. Under the action of the Kobe wave and the Qian'an wave, the H-shaped damper exhibited more excellent seismic performance. Compared with frames with T-shaped connectors, the maximum vertex displacement and the maximum inter-story shift angle of frames with H-shaped dampers decreased by 3.44% to 12.39% and 9.55% to 16.15%. The web perforation form of H-shaped dampers somewhat affected the seismic behavior of steel frame structures. Among them, diamond dampers could minimize structural deformation.

Floor slab composite action effects on hysteresis behaviors of steel-framed-tube structures with shear links

The utilization of spandrel beams with a low span-to-depth ratio in a Steel-Framed Tube (SFT) structure can potentially diminish its ductility and energy dissipation characteristics. Conversely, integrating an SFT with end-plate-connected, replaceable low-yield-point steel shear links (SFT-RLYPSL) may significantly enhance its seismic response. This study introduces a prototype SFT-RLYPSL configuration designed to mitigate the premature separation of a reinforced concrete (RC) slab from the spandrel beams, a phenomenon observed in prior research. A series of finite element (FE) models were established, utilizing the prototype structure as a basis, to systematically investigate the impact of various parameters, including the presence and thickness of the RC slab, concrete strength, shear link length, and initial spandrel beam stiffness, on the cyclic behavior of an SFT-RLYPSL substructure module. Additionally, the failure mechanisms of the substructure module were assessed. The findings of this study reveal that the utilization of T-shaped connectors can effectively delay the pull-out of studs from the RC slab, especially under substantial vertical displacement of the spandrel beam. The initial elastic stiffness and load-carrying capacity of the substructure module can be significantly enhanced through the promotion of RC slab composite action. An optimal shear link length ratio falls within the range of 0.95 to 1.25, and given the assumption of LYP225 steel shear links with length ratios of 0.95 to 1.25 in the SFT-RLYPSL, the recommended minimum thickness and concrete grade for the RC slab, based on numerical simulation results, are 120 mm and C30, respectively. It is further recommended to employ C30 concrete for an RC slab with a thickness of 120 mm. Finally, a restoring force model is proposed, accurately reflecting the observed mechanical behaviors of the SFT-RLYPSL substructure module.

Analytical Investigation into the Rotational Performance of Glulam Bolted Beam-Column Connections under Coupled Bending Moment and Shear Force

Considering the glulam beam-column connection form and the number of bolts, monotonic loading test and finite element analysis was carried out on 9 connection specimens in 3 groups to study the rotational performance and failure mode of the connection. The test results revealed that compared with U-shaped connectors, T-shaped connectors can effectively improve the ductility of connections, and the increase in the number of bolts can reduce the initial stiffness and ductility of connections. By theoretical analysis, formulas for calculating the initial stiffness and ultimate moment of connections were deduced. Subsequently, the moment-rotation theoretical model of connections was established based on the formulas, which were validated according to the test data and simulation results. The proposed model can not only improve the current theoretical system of heavy-duty glulam beam-column structure but also provide a theoretical basis for calculating the mechanical properties of the glulam beam-column connection.

One-Step Aerosol Synthesis of SiO2-Coated FeNi Particles by Using Swirler Connector-Assisted Spray Pyrolysis

Silica-coated soft magnetic particles are essential for some powder magnetic cores consisting of primary (coarse particles) and secondary (fine particles) soft magnetic particles in the advancement of electric devices. Herein, we report the first investigation on the direct synthesis of submicron-sized silica-coated FeNi (FeNi@SiO2) particles as the secondary particle using a connector-assisted spray pyrolysis route. Provided by computational fluid dynamics calculation in applying different connector types, i.e., T-shaped and swirler, we found that the mixing performance between FeNi and HMDSO vapor in the swirler connector played an important role in resulting heterogeneous nucleation, which is crucial for obtaining the higher coating ratio (CR) and fewer undesired nanoparticles than that of the T-shaped connector. The as-prepared submicron-sized FeNi@SiO2 particles (353 nm) with the highest CR (95.9%) demonstrated a remarkable DC bias characteristic (Isat) and eddy current loss values on a powder magnetic core, promising the practical application in manufacturing soft magnetic components.

Experimental seismic behaviors of different connections to CFST end-columns in shear walls

A new hot-rolled T-shaped connector (HTC) connection was proposed herein to solve the connecting difficulties between H-shaped beams and small-sized composite walls or CFST columns in steel residential buildings. The connection utilizes the hot rolled flange-to-web arch transition in hot rolled beams as the beam-end connector. In this way, the hot-rolled arch transition of the connector provides a smooth section transition at the column face junction to avoid stress concentrations and premature fracture problems in traditional welded junctions. The new connections, together with the existing endplate type and side plate type connections, were applied to a specially-shaped corrugated plate shear wall system. Seismic loading tests were performed to explore seismic behaviors and the applicability of those connections in steel residential buildings. Results indicated that the side plate connections and HTC connections exerted good hysteretic performance with stable hysteretic behaviors, slow stiffness degradation, good energy dissipation ability, and satisfactory ductility. The endplate connection experienced early fracture failure of the side plate to endplate welds. In addition to the satisfactory seismic performance, the proposed HTC connections had no extended stiffeners and little intrusion into the indoor space, and could be easily hidden within partition walls.

An Experimental Study on Finding Prequalified Connectors between the Wall and Steel Frame Infilled with Autoclave-Cured Aerated Concrete Blocks

ABSTRACT In this study, experiments are conducted to investigate the effect of wall-to-frame connectors on in-plane/out-of-plane (IP/OOP) behavior of the steel frames infilled with autoclave-cured aerated concrete (AAC) wall to find a reasonable connection type. Six infilled frames with different connection designs were tested. In specimens with V-shaped and T-shaped connectors, the OOP stability of the wall was maintained, the frame–wall interaction was ignored, and the wall remained intact up to 2.5% IP drift. They compensated the stiffness degradation and strength reduction of the frame after 2.5% drift. These two connectors can be used as prequalified connectors in the steel structures.

Behaviour of thick marine deposits subjected to vacuum combined with surcharge preloading

This paper presents a case study on the improvement of thick marine deposits. A new method that combines vacuum pressure and surcharge load with no need for a sand cushion is proposed and evaluated. The main features of this method are as follows: (1) each integrated prefabricated vertical drain (PVD) is connected directly to a branch pipe, which is in turn connected to a main pipe with a T-shaped connector, and (2) a less expensive hill-skill soil layer is used to replace the sand cushion. After improving the soil by using this method, the total ground settlement, the lateral deformation and the undrained shear strength were all greater for a 20-m PVD than for a 15-m PVD. The average degrees of consolidation achieved were both greater than 80%. This method could provide design criteria for reclaimed land in other projects.

Experimental study on shaped steel shear connectors used in large-scale composite structures

Steel–concrete–steel (SCS) composite structures are used in immersed tunnels and are superior in capacity, constructional facility, etc. in comparison with traditional structures. L- and T-shaped shear connectors are two typical types of shear connectors used in the composite structures. To investigate the mechanical performances of the connectors, 12 groups of push-out tests were conducted. Interfacial slip, bending deformation of the connector web, and strains on the concrete, were measured. Failure modes of concrete crushing were observed in all tested specimens. Evoked outcomes indicated that the performances of the L- and T-shaped connectors were controlled by the non-reinforced concrete. The strain measured in the tests indicated that stress concentration and concrete crushing were mainly located at the root regions. The shear-force–slip relationship, strain distribution, etc., were further analyzed and discussed. Accordingly, the currently available methods used to evaluate the ultimate strength are discussed. These methods were found to be accurate in the case of the L-shaped shear connectors but too conservative for T-shaped shear connectors. A scaling factor was proposed for modification. Finally, 122 groups testing data was collected for validation, which proved that the modified method has adequate accuracy and can be used in various design applications. The experiment data of the L-shape and T-shape shear connectors with different experimental methods were studied which shows the push-out specimens and beam specimens have similar performance. The results of the experimental study and theoretical analyses indicate that the L-shape and T-shape shear connectors have similar mechanical properties while the T-shape shear connectors have better performance concerning the shear stiffness and the ultimate shear strength.

Processes of isothermal formation of hollow t-shaped tubes made of high-strength alloys

Slow hot deformation makes it possible to achieve a significant growth of deformation without the destruction of the material and avoiding a significant decrease in pressure when forming difficult-to-deform non-ferrous alloys. This is especially important when it is necessary to obtain products that operate in severe conditions, for example, in propulsion systems. The article discusses the manufacture of hollow T-shaped connectors by means of forming, namely, by means of extrusion in orthogonal planes and piercing. It was assumed that these operations took place under isothermal conditions. Expressions for calculating the force values of the processes are obtained. Using these expressions, the influence of the degrees of deformation on the forces of extrusion and piercing was investigated.

An experimental study on the effect of frame-to-wall connection type on the seismic behavior of steel frames infilled with autoclave-cured aerated concrete blocks

In this article, in order to find some reliable connection types for avoiding the infill failure, an experimental study is conducted on six half-scale single-story single-bay specimens, including one bare frame and five steel frames with autoclave-cured aerated concrete walls, each having different frame-to-wall connection types. Polyurethane adhesive was used in bed joints of the autoclave-cured aerated concrete walls as a mortar. The specimens were tested under displacement-controlled loading to examine their effect on the in-plane behavior of steel frames. The results suggested that V- and T-shaped connectors can be used as prequalified connectors between the wall and the frame. In specimens with these connectors, the interaction between infill and frame was ignorable and the infill remained intact up to life safety performance level (2.5% drift ratio). Furthermore, the application of these connectors resulted in a two-level performance of the infill whereby the frame stiffness degradation and strength deterioration after the drift ratio of 2.5% was compensated.

Cyclic testing and parametric study of bolted beam-height adjustable steel beam-to-column connections

A kind of bolted beam-height adjustable beam-to-column connections (BHA connections) is proposed for moment-resisting steel frames. It is applicable when the height of beams change in small ranges. A BHA connection is composed of a T-shaped connector, an L-shaped connector with ellipse-type blot holes and bolts. A cyclic test on four full-scaled subassemblies and a series of numerical parametric analyses of BHA connections were conducted to study their mechanical performance. The test results show that the BHA connections with properly stiffened L-shaped connectors possessed good hysteretic properties, stabile secant stiffness and load-carrying capacity degradation and excellent energy dissipation capacity. And the effect of connector slippage and beam web eccentricity was negligible. It can be found in the parametric study that the flange thickness of T-shaped connectors played a pivotal role both in the load-carrying capacity and elastic stiffness of BHA connections, and the elastic stiffness was also affected by the thickness of T-shaped connector webs, L-shaped connector flanges and webs, and column stiffeners. Moreover, the numerical results also demonstrated that the column stiffeners in joint regions could improve the efficiency of load transfer between beams and columns. This kind of connections can be used to assemble steel frames expediently.

A LONG PATHLENGTH SPECTROPHOTOMETRIC TEGAFUR DETECTOR USING A LIQUID-CORE WAVEGUIDE

A Liquid-Core Waveguide (LCW) detection system for high sensitive determination of tegaful (FT) was developed. In this system the LCW cell was connected to the end of a hollow cathode lump and the other end to a UV spectrometer. A sample solution containing FT was pumped to the LCW cell through a T-shaped connector. A UV absorption of analyte was detected by the UV spectrometer. The configuration of connectors of LCW cell to the light source and the UV detector was designed. Stable and high responses of FT were obtained in a double tube system in which an edge of LCW cell was covered with another tube with large diameter was set in the T-connector. It was found that the UV absorption response of FT obtained in this LCW system depends on the core length and the concentration of FT. The sensitivity of FT obtained by using 65 cm of the LCW cell length was 10-fold higher than that of using 1 cm cell which was often used with a conventional UV-visible detector.

Hydrogenation Reactions Utilizing Capillary Column Reactors

A less-space and low-cost capillary reactor was developed. Tetrakis(triphenylphosphine)palladium was immobilized onto the inner surface of the capillary column by using the polymer micelle incarceration method. The palladium-immobilized capillary was connected to a T-shaped connector, and hydrogen and a substrate were fed via the connector. Hydrogenation of 1-phenyl-1-cyclohexene gave phenylcyclohexane in a quantitative yield (2.8 mmol/h). No leaching of palladium was observed by ICP analysis after the reactions.

Triphase Hydrogenation Reactions Utilizing Palladium‐Immobilized Capillary Column Reactors and a Demonstration of Suitability for Large Scale Synthesis

AbstractWe have developed a practical and highly productive system for hydrogenation reactions utilizing capillary column reactors, which occupy less space than ordinary batch systems, are low cost and easy to handle, and show feasibility toward large‐scale chemical synthesis. Palladium‐containing micelles were immobilized onto the inner surface of the capillaries. Nine palladium‐immobilized capillaries were assembled and connected to a T‐shaped connector, and hydrogen and a substrate solution were fed to capillaries via the connector. Hydrogenation of 1‐phenyl‐1‐cyclohexene (1) proceeded smoothly to give phenylcyclohexane in quantitative yield. The capillaries themselves occupy only ca. 0.4 mL and a high space‐time yield has been achieved (124.3 mg/17 min/0.4 mL). In addition, leaching of palladium was not detected by ICP analysis after reactions.

Direct Measurement of Nitric Oxide during Experimental Cardiopulmonary Bypass

We developed a system to measure nitric oxide (NO) concentration during cardiopulmonary bypass in anaesthetized pigs (n = 6). A T-shaped connector, attached to an NO sensor, was mounted in the extracorporeal circuit at two measuring sites: proximal to the membrane oxygenator (venous side) and distal to the arterial line filter (arterial side). After performing a preliminary validation study, we measured plasma NO concentration before and during total cardiopulmonary bypass circulation (non-pulsatile flow 1.5 l/min) and without pulmonary ventilation. After establishing bypass, PaO2 was 318 - 393 mmHg; when PaO2 was decreased to 80 - 100 mmHg, plasma NO concentration in the arterial circuit fell by 39.2 +/- 15.6 nM. There was no observable change in plasma NO concentration at the venous circuit. This new system could be useful in monitoring NO concentration during cardiac surgery with cardiopulmonary bypass, and for understanding the possible pathophysiological roles of hyper-nitric oxaemia in cardiopulmonary bypass-related cardiovascular complications.

T-shaped spin filter with a ring resonator

A planar ballistic T-shaped structure with a ring resonator attached is shown to be highly effective in filtering electron spin from an unpolarized source into two output fluxes with opposite and practically pure spin polarizations. The operability of the proposed device relies on the peculiar spin-dependent transmission properties of the T-shaped connector in the presence of Rashba spin–orbit interaction as well as the difference in dynamic phase gain of the two alternative paths around the ring resonator through upper and lower branches for even and odd eigenmodes.

A flow cell suitable for time-resolved X-ray crystallography by the Laue method

A low-cost flow cell was produced using a commercially available T-shaped connector and used for collecting Lane diffraction data. Since this flow cell can be easily constructed within a few minutes, it is suitable for Lane experiments at synchrotron laboratories.

Clasp retained devices for drainage of marsupialized cysts.

Abstract A clasp-retained drainage tube is suggested as a means of maintaining patency of a cyst orifice when long-term drainage is anticipated after marsupialization. Also, commercially available T-shaped tubing connectors are suggested as temporary drainage devices.