Structural design of carbon/epoxy bio‐inspired wind turbine blade using fluid/structure simulation

The purpose of this paper is to present the structural design procedure of a low‐speed, horizontal axis, bio‐inspired wind turbine blade made of carbon/epoxy. The methodology initiates with the mechanical characterization of the carbon fiber composite material. An aerodynamic simulation using Computational Fluid Dynamics (CFD) method is performed in order to obtain the pressure distribution profile of the blade. This result is coupled with a Finite Element Analysis (FEA) to carry out an iterative design process through a Fluid‐Structure Interaction (FSI) simulation. Different stacking sequences of laminates are evaluated to find a configuration which allows balance between aerodynamic and dynamic inertial loads, ensuring an almost undeformed geometry during wind turbine's operation. The final structural design of the blade consists in six regions with different laminates. These are balanced and symmetric with distinct thickness characteristics and stacking sequences, which vary in three different orientations: 0^°, ± 45^° and 90^°, achieving a minimum deflection at the tip close to 3.11 cm, and a total weight of 3.6 kg of a 1.8 m radius blade, even with the restrictions imposed by the non‐conventional geometry. Copyright © 2016 John Wiley & Sons, Ltd.     

变压器环氧浸渍纸绝缘套管运行情况分析

介绍了环氧浸渍纸绝缘电容套管的结构,研究分析了几起套管典型故障,探讨了套管状态量介损值随运行时间的变化,并对设备运行维护及检修试验提出了几点建议。     

Evaluation of performance of various color‐difference formulae using an experimental black dataset

The objective of this study was to develop a specific visual dataset comprising black‐appearing samples with low lightness (L* ranging from approximately 10.4 to 19.5), varying in hue and chroma, evaluating their visual differences against a reference sample, and testing the performance of major color difference formulas currently in use as well as OSA‐UCS‐based models and more recent CAM02 color difference formulas including CAM02‐SCD and CAM02‐UCS models. The dataset comprised 50 dyed black fabric samples of similar structure, and a standard (L*= 15.33, a* = 0.14, b* = ?0.82), with a distribution of small color differences, in ΔE^*_ab, from 0 to approximately 5. The visual color difference between each sample and the standard was assessed by 19 observers in three separate sittings with an interval of at least 24 hours between trials using an AATCC standard gray scale for color change, and a total of 2850 assessments were obtained. A third‐degree polynomial equation was used to convert gray scale ratings to visual differences. The Standard Residual Sum of Squares index (STRESS) and Pearson's correlation coefficient (r), were used to evaluate the performance of various color difference formulae based on visual results. According to the analysis of STRESS index and correlation coefficient results CAM02 color difference equations exhibited the best agreement against visual data with statistically significant improvement over other models tested. The CIEDE2000 (1:1:1) equation also showed good performance in this region of the color space. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 589–598, 2014     

Safety-enhanced Collaborative Framework for Tele-operated Minimally Invasive Surgery Using a 7-DoF Torque-controlled Robot

International Journal of Control, Automation and Systems - In this paper, a safety-enhanced collaborative control framework is proposed for tele-operated minimally invasive surgery (MIS) using a...     

Adaptive input shaping for single-link flexible manipulators using an algebraic identification

This work proposes an adaptive control scheme applied to single link-flexible manipulators, which combines a feedback controller of the joint angle with an adaptive input shaper updated by an algebraic non-asymptotic identification. The feedback controller is designed to guarantee trajectory tracking of the joint angle, simplifying thus the input shaper, which can be designed for the arm dynamics only. The input shaper is updated by an algebraic identification of the natural frequency corresponding to the first vibration mode of the arm. In addition, the influence of the assumptions adopted to derive the algebraic identification on the performance of the estimation is studied. Finally, the proposed adaptive control strategy is implemented in practice.     

Synthesis method based on solution regions for planar four-bar straight-line linkages

An analytical method for synthesizing and selecting desired four-bar straight-line mechanisms based on solution regions is presented. Given two fixed pivots, the point position and direction of the target straight-line, an infinite number of mechanism solutions can be produced by employing this method, both in the general case and all three special cases. Unifying the straight-line direction and the displacement from the given point to the instant center into the same form with different angles as parameters, infinite mechanism solutions can be expressed with different solution region charts. The mechanism property graphs have been computed to enable the designers to find out the involved mechanism information more intuitively and avoid aimlessness in selecting optimal mechanisms.     

如何处理工程造价审计中存在的问题

针对工程造价审计存在的阴阳合同条款、竣工图修改不变、变更及签证管理混乱、审计人员良莠不齐等问题,提出了优化建议,指出工程造价审计应加强合同的阳光透明、强化变更与签证管理、完善审计工作。     

Immediate water quality assessment in shrimp culture using fuzzy inference systems

The continuous monitoring of physical, chemical and biological parameters in shrimp culture is an important activity for detecting potential crisis that can be harmful for the organisms. Water quality can be assessed through toxicological tests evaluated directly from water quality parameters involved in the ecosystem; these tests provide an indicator about the water quality. The aim of this study is to develop a fuzzy inference system based on a reasoning process, which involves aquaculture criteria established by official organizations and researchers for assessing water quality by analyzing the main factors that affect a shrimp ecosystem. We propose to organize the water quality parameters in groups according to their importance; these groups are defined as daily, weekly and by request monitoring. Additionally, we introduce an analytic hierarchy process to define priorities for more critical water quality parameters and groups. The proposed system analyzes the most important parameters in shrimp culture, detects potential negative situations and provides a new water quality index (WQI), which describes the general status of the water quality as excellent, good, regular and poor. The Canadian water quality and other well-known hydrological indices are used to compare the water quality parameters of the shrimp water farm. Results show that WQI index has a better performance than other indices giving a more accurate assessment because the proposed fuzzy inference system integrates all environmental behaviors giving as result a complete score. This fuzzy inference system emerges as an appropriated tool for assessing site performance, providing assistance to improve production through contingency actions in polluted ponds.     

Improving the Interfacial Microstructure Evolution of Ti/Stainless Steel GTA Welding Joint by Employing Cu Filler Metal

In the present work, Cu alloys as filler metals were applied to improve interfacial microstructural evolution during the process of gas tungsten arc (GTA) welding of TA15 titanium alloy with 18-8 stainless steel (SS). Results indicated that the interfacial brittle microstructure evolution of Ti/SS GTA welding joint was improved by adopting Cu alloy as the filler metal. Microstructure in the reaction zone (RZ) is composed of massive precipitations including brittle phosphide (Ti₃P), Ti₂Cu₃ and Ti(Cu, Fe) intermetallic compounds (IMCs), while the fusion zone (FZ) near SS is mainly composed of Cu-rich clumps and α-Fe+(Fe, Cr)₃P skeleton eutectic microstructure. Ti₂Cu₃ precipitations provided substrate for the heterogeneous nucleation of Ti₃P whose regular tetragonal and irregular morphologies are attributed to the proposed two kinds of forming mechanism. During the reaction of P with Ti₂Cu₃, the dropping of residual Ti₂Cu₃ contributed to the formation of macroporous in the middle of irregular Ti₃P precipitations. The dispersive distribution of massive brittle precipitations in the RZ leads to the fluctuant distribution of microhardness, which is up to about 700HV_0.5.