The in-situ measurement of axial stress in beams may prevent structural anomalies, such as unexpected buckling. We describe the coupling mechanism between highly nonlinear solitary waves (HNSWs) propagating along a granular system and a beam in contact with the granular medium to assess the ability of HNSWs to measure axial stress. One and two straight chains of particles were considered and the effect of the particles' diameter and material was evaluated to find those designs that maximize the sensitivity to the variation of axial stress. In the future, our findings may be used to develop a novel system for the nondestructive inspection of beams. 相似文献
In this paper, a CMOS mm-wave phase locked loop (PLL) with improved voltage controlled oscillator (VCO) and injection-locked frequency divider (ILFD) at operational harmonic frequency 125 GHz is presented. The VCO structure uses the bulk effective and MOS varactor capacitor to adjust parasitic capacitor of the cross coupled pair. It obtains 2th harmonic frequency with 24% tuning range (110–140 GHz) by applying?±?1.2 V input voltage variation. The divide-by-4 ILFD circuit uses a cross coupled VCO with three injection transistors acting in linear and nonlinear regions. The frequency dividers such as divided-by-4 ILFD, subsequent current mode logic (CML) and true single phase clock (TSPC) as divider chain with ratio 1/256 are used to synthesize frequency 244 MHz which is compared to reference frequency, 244 MHz in the PLL. Simulation results of the proposed PLL circuit are obtained after extracting post layout (with total chip size of 0.29 mm2) in 65 nm CMOS standard technology and @ 1.2 V power supply voltage. The obtained results confirm theoretical relations and indicate that the proposed circuit has good figure of merit (FoM), and higher tuning range and lower die area than the recent designs.
The duty of shipboard cranes is to lift and lower loads, as well as to handle floating facilities to lower or higher positions by means of fixed wire ropes, pulleys, and hook, and so forth. Hence, they play an important role in the productivity of servicing or manufacturing systems. Since each crane has distinguished properties than the others with respect to criteria and decision-makers (DMs) may express the different standpoints regarding them, the crane selection problem (CSP) can be considered as a group multicriteria decision-making (MCDM) problem. In this paper, interval type-2 fuzzy sets (IT2FSs) are first used to evaluate cranes with respect to criteria. The synthetic value method of IT2FSs is then handled to integrate the ratings expressed as IT2FSs of each crane with respect to criteria into the single fuzzy rating. Finally, the multiobjective criteria importance through inter-criteria correlation (CRITIC)–technique for order of preference by similarity to ideal solution (TOPSIS) approach is applied to solve the CSP in which CRITIC and TOPSIS are used to determine the objective weights and score of cranes, respectively. In addition, the limit distance mean (LDM) is introduced for ranking interval type-2 fuzzy ratings in the above two techniques. In contrast, to demonstrate the potential application, the proposed methodology is implemented in a real case study and the ranking results are compared with those published in the literature. 相似文献
Applied Intelligence - Configuration of a supply chain network is a critical issue that contributes to choose the best combination for a set of facilities in order to attain an effective and... 相似文献
In view of the intermittency and uncertainty associated with both the electricity production sector of restructured power system and their competitive markets, it is necessary to develop an appropriate risk managing scheme. So that it is desirable to trade-off between optimum utilization of intermittent generation resources (i.e. renewable energy resources), uncertain market prices and related risks in order to maximize participants' benefits and minimize the corresponding risks in the multi-product market environment. The main goal of this paper is to investigate risk management by introducing a novel multi-risk index to quantify expected downside risk (EDR) which is caused by both the wind power and market price uncertainties. Value-at-Risk (VaR) method is used to assess the mentioned risk issue by the proposed weighted EDR, so that an optimal trade-off between the profit and risk is made for the system operations. Also, the roulette wheel mechanism is employed for random market price scenario generation wherein the stochastic procedure is converted into its respective deterministic equivalents. Moreover, the autoregressive integrated moving average (ARIMA) model is employed to characterize the stochastic wind farm (WF) generation by predetermined mean level and standard deviation of wind behavior as well as temporal correlation. The problem is formulated as a mixed-integer stochastic framework for a hydro-wind power system scheduling and tested on a generation company (GENCO). 相似文献
A highly sensitive electrochemical sensor for the detection of trichloroacetic acid (TCA) is developed by subsequent immobilization of phthalocyanine (Pc) and Fe(II) onto multiwalled carbon nanotubes (MWCNTs) modified glassy carbon (GC) electrode. The GC/MWCNTs/Pc/Fe(II) electrode showed a pair of well-defined and nearly reversible redox couple correspondent to (Fe(III)Pc/Fe(II)Pc) with surface-confined characteristics. The surface coverage (Γ) and heterogeneous electron transfer rate constant (ks) of immobilized Fe(II)–Pc were calculated as 1.26 × 10? 10 mol cm? 2 and 28.13 s? 1, respectively. Excellent electrocatalytic activity of the proposed GC/MWCNTs/Pc/Fe(II) system toward TCA reduction has been indicated and the three consequent irreversible peaks for electroreduction of CCl3COOH to CH3COOH have been clearly seen. The observed chronoamperometric currents are linearly increased with the concentration of TCA at concentration range up to 20 mM. Detection limit and sensitivity of the modified electrode were 2.0 μM and 0.10 μA μM? 1 cm? 2, respectively. The applicability of the sensor for TCA detection in real samples was tested. The obtained results suggest that the proposed system can serve as a promising electrochemical platform for TCA detection. 相似文献
The toughening of epoxy resins by incorporating inorganic fillers is of great importance nowadays, due to their wide range of applications. The present work reports the results of the addition of barium carbonate into a polymeric matrix containing diglycidyl ether of bisphenol-A (DGEBA) epoxy resin using 1,8-naphthalene diamine (1,8-NDA) as hardener to produce a novel composite for industrial applications. Cure kinetics of the composite system was investigated by means of differential scanning calorimeter (DSC) in dynamic mode. Kinetics of the reaction was interpreted according to the two isoconversional methods of Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (OFW). Using non-isothermal conditions, average value of the cure reaction activation energy in the propagation step was determined to be 57 and 60.2 kJ/mol for the KAS and OFW models, respectively. DMTA and TGA measurements were used in order to assess the effectiveness of the filler amount (2 Phr) on the final mechanical and thermal properties of the produced composite. The results verified that the thermal stability of the composite could be improved with the incorporation of BaCO3. Microstructural observations from images analysis of SEM micrographs revealed that the barium salt was dispersed into polymer matrix homogeneously. 相似文献
The electrocardiographic error of left arm/left leg lead reversal is difficult to identify. PI amplitude greater than PII as a terminal positive component to PIII may diagnose 90% of such errors. 相似文献