In a composite column, the performance of both the concrete and steel has a considerable effect on the structural behaviour under different loading conditions. This study applies several artificial intelligence (AI) techniques to optimise the bearing capacity of concrete-filled steel tube (CFST) columns. First, the bearing capacity values of the CFST columns are estimated by an artificial neural network (ANN) technique. Using 303 datasets, the outer diameter, concrete compressive strength, tensile yield stress of the steel column, thickness of the steel cover, and length of the applied samples are considered as the model inputs. Following a series of analyses, several ANN models are developed. The ANN model with 8 neurons and 250 iterations is determined as the best model to predict the bearing capacity of the CFST columns. Subsequently, the invasive weed optimisation (IWO) technique, which is considered the most current optimisation algorithm, is developed to maximise the results of the bearing capacity by considering the selected ANN model. To highlight the ability of IWO, the artificial bee colony (ABC) algorithm is also applied. Consequently, it is found that both optimisation algorithms can design input parameters such that the maximum value of the bearing capacity can be obtained. The bearing capacity of the CFST columns from the ABC and IWO techniques indicates that IWO has a better capability of maximising the bearing. Thus, IWO can optimise similar problems with a high rate of performance.
We propose an architecture based on a hybrid E2E-ERN approach allowing ERN protocols to be inter-operable with current IP-based networks. Without introducing complex operations, the resulting E2E-ERN protocol provides inter and intra protocol fairness and benefits from all ERN advantages when possible. We detail the principle of this novel architecture, called IP-ERN, and show that this architecture is highly adaptive to the network dynamics and is compliant with every TCP feature, IPv4, IPv6 as well as IP-in-IP tunneling solutions. As a possible use case, we test this architecture as a potential candidate to replace Performance Enhancing Proxies (PEPs) commonly-used over satellite IP-based networks. Compared to splitting PEP, the IP-ERN architecture does not break the E2E connectivity, still achieves high satellite link utilization and fairness without needs of extra fault tolerant mechanisms. 相似文献
The use of hydraulic systems in industrial applications has become widespread due to their advantages in efficiency. In recent
years, hybrid actuation systems, which combine electric and hydraulic technology into a compact unit, have been adapted to
a wide variety of force, speed and torque requirements. A hybrid actuation system resolves energy consumption and noise problems
characteristic of conventional hydraulic systems. A new, low-cost hybrid actuator using a DC motor is considered to be a novel
linear actuator with various applications such as robotics, automation, plastic injection-molding, and metal forming technology.
However, this efficiency gain is often accompanied by a degradation of system stability and control problems. In this paper,
to satisfy robust performance requirements, tracking performance specifications, and disturbance attenuation requirements,
the design of a robust force controller for a new hybrid actuator using Quantitative Feedback Theory (QFT) is presented. A
family of plant models is obtained from measuring frequency responses of the system in the presence of significant uncertainty.
Experimental results show that the hybrid actuator can achieve highly robust force tracking even when environmental stiffness
set-point force varies. In addition, it is understood that the new system reduces energy use, even though its response is
similar to that of a valve-controlled system. 相似文献
In this paper we describe the theoretical background and practical application of QNA-MC (queueing network analyser supporting multicast), a tool for the analytical evaluation of multicast protocols. QNA-MC is based on the QNA method, which (approximately) analyses open networks of GI|G|m queues. In contrast to standard QNA, QNA-MC allows for the specification and evaluation of multicast routes. As in real multicast communication, packets leaving a particular node can be copied and deterministically routed to several other nodes. In order to analyse such queueing networks, QNA-MC converts the multicast routes to a suitable input for standard QNA. From the results delivered by QNA, QNA-MC then derives several performance measures for multicast streams in the network. A validation of QNA-MC, via a comparison to simulation results, shows that QNA-MC yields very good results. Finally, we give a detailed application example by evaluating different multicast routing algorithms for a realistic video conferencing scenario in the European MBONE. 相似文献
A simple approach was explored to prepare N-doped anatase TiO2 nanoparticles (N-TiO2 NPs) from titanium chloride (TiCl4) and ammonia (NH3) via sol–gel method. The effects of important process parameters such as calcination temperatures, NH3/TiCl4 molar ratio (RN) on crystallite size, structure, phase transformation, and photocatalytic activity of titanium dioxide (TiO2) were thoroughly investigated. The as-prepared samples were characterized by ultraviolet–visible spectroscopy, x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The photocatalytic activity of the samples was evaluated upon the degradation of methylene blue aqueous solution under visible-light irradiation. The results demonstrated that both calcination temperatures and NH3/TiCl4 molar ratios had significant impacts on the formation of crystallite nanostructures, physicochemical, as well as catalytic properties of the obtained TiO2. Under the studied conditions, calcination temperature of 600°C and NH3/TiCl4 molar ratio of 4.2 produced N-TiO2 with the best crystallinity and photocatalytic activity. The high visible light activity of the N-TiO2 nanomaterials was ascribed to the interstitial nitrogen atoms within TiO2 lattice units. These findings could provide a practical pathway capable of large-scale production of a visible light-active N-TiO2 photocatalyst. 相似文献
Zinc aluminum hydrotalcite intercalated with molybdate (HTM) and modified by 3-glycidoxypropyltrimethoxysilane (HTM-GS) was prepared and incorporated into a waterborne epoxy coating. The synthesized HTM-GS was characterized by FTIR, XRD, SEM, and TEM. The inhibitive action of HTM-GS on carbon steel was evaluated using electrochemical measurement and SEM/EDX analysis. The corrosion protection of the waterborne epoxy coating containing HTM-GS was evaluated and compared to that of the pure waterborne epoxy coating and the waterborne epoxy coating containing HTM by salt spray test and adhesion measurement. It was shown that the molybdate was intercalated in the hydrotalcite structure and the molybdate contents in HTM and HTM-GS were 16.0 and 13.2 wt%, respectively. The polarization curves obtained on the carbon steel electrode showed that HTM and HTM-GS are anodic corrosion inhibitors, and their inhibition efficiencies at concentration of 3 g/l were 92.0 and 94.7%, respectively. Additionally, HTM and HTM-GS at concentration of 0.5 wt% improved corrosion resistance and adhesion of waterborne epoxy coatings. Surface modification by 3-glycidoxypropyltrimethoxysilane ameliorated the dispersion of HTM in epoxy matrix and the effect of HTM on protection properties of waterborne epoxy coating. 相似文献
Perovskite oxides like SrTiO3 at the nanoscale are of interest for emerging applications,including high-k dielectrics and sensors.However,their synthesis requires long calcination at the elevated temperature,which is a barrier of their application to flexible electronics.Here,an effective laser-assisted sol-gel method to patternably produce SrTiO3 nanoparticles (-100 nm) in selective areas on polyimide substrates (coated with ITO) is introduced.Importantly,the violet-laser power is just 1 W but sufficient to crystallize the material in a short period (a few seconds).Furthermore,developing a flexible device platform using carbon nanotubes (CNT) and SrTiO3 nanoparticles for detection of humidity changes at room temperature is proposed.The sensor platform has both capacitive and resistive sensing abilities.The resistive mode with a lower power usage (about 0.2 μW) is suitable for long monitoring of humidity in the range of 2% RH and above.The capacitive mode with higher sensitivity,faster response/recovery time (1-3 min),and lower detection limit (0.5% RH) can be used for calibration purposes.The performance of the flexible sensor is still maintained after 5000 bending cycles at 1.5-cm radius.Altogether,our synthesis method and the flexible sensor show chances for mass-producing perovskite oxides at low cost for wearable electronics. 相似文献
Compression creep tests (CCTs) have been widely used in phenomenological characterization of viscoelastic materials such as glasses. However, disturbed by specimen-tool interface friction, the real stress-strain data regarding the pure viscoelastic deformation are frequently misestimated in conventional CCTs, causing decreased accuracies of the derived viscoelastic parameters. This study proposes a comprehensive CCT-based approach to develop a viscoelastic model with weakened frictional disturbance and enhanced predictive accuracy. An integrated calculation procedure is first built to mathematically characterize the frictional and viscoelastic behaviors of glass during compression. Uniaxial CCTs of a typical borosilicate glass (L-BAL42) are then performed at varied frictional conditions. The quantified coefficients of interface friction indicate that a minor frictional disturbance is achieved when Nickel foils are used as interfacial layers, whereby a more realistic viscoelastic constitutive relation of the glass is derived. The obtained frictional and viscoelastic constants are further incorporated into computational modeling of the CCT and precision molding processes. The demonstrated consistencies between the simulated and measured results (creep displacement and molding force) suggest that, by technically slashing the interface friction and theoretically correcting the friction-involved stress in CCTs, the frictional disturbance to experimental stress-strain data can be effectively weakened, and a viscoelastic model of enhanced predictive accuracy can be thus developed. 相似文献