bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrous Oxide Sedation and Bispectral Index
Authors: IŞIK Berrin , TÜZÜNER Tamer , TEZKİRECİOĞLU Melih , ÖZTAŞ Nurhan 
Published: September 2019

ABSTRACTObjectives: To determine whether bispectral analysis (BIS) changes during nitrous oxide (N2O) sedation in anxious children undergoing extraction of primary teeth.Methods: In this prospective study 45, ASA physical status I children, aged between 7 to 12 years and scheduled for primary teeth extraction under N2O/O2 sedation are included. At baseline (T0) and during the sedation procedure (T1-6); BIS levels, Ramsay Sedation Scores (RSS), oxygen saturation (Sp02), and heart rate (HR) were recorded at one-minute intervals. Forty percent N2O in O2 was given by a nasal hood, and N2O concentration was enhanced to 60% in a two-minute period. Paired measurements of BIS levels with Observer’s Assessment of Alertness and Sedation (OAA/S) scores were obtained during sedation procedureResults: Since 5 patients refused application of the nasal hood, a total 40 of the original 45 subjects completed the study. Mean age and weight of the children were 9.5 ± 1.4 years and 23.7 ± 9.7 kg, respectively. Nitrous oxide inhalation produced no changes in BIS levels despite a sedation level in OAA/S scores were observed at 40-60% N2O concentrationsConclusions:BIS values do not change during N2O/O2 sedation and the BIS monitor is not appropriate to evaluate the depth of sedation provided by N2O/O2 during primary teeth extraction in children. (Eur J Dent 2007;1:240-245)
Endoscopic tattooing of small bowel by double - balloon endoscopy
Authors: Nina Abild , Orhan Bulut 
Published: September 2019

ABSTRACTInflammatory vascular polyps that are complicated by bleeding are difficult to diagnose and localise during the operation. With the improvement in the diagnosis of the small bowel tumours with double balloon endoscopy, the preoperative localization of the lesion is essential to undertake appropriate surgery, and to reduce the time for surgery and avoid resection of wrong segment of small bowel. Double balloon endoscopic tattooing of small bowel tumours and lesions is a new modality to ease the surgery when resection of small bowel is indicated. The literature about double balloon endoscopic tattoo is scant. We present a rare case of small bowel polyp that caused bleeding and the successful use of double balloon endoscopic tattoo preoperatively for the localization of the lesion during surgical procedure. (Dig Endosc 2013;4(2):49-51)
A Hamiltonian-based analytical approach for three-dimensional heat conduction of cylinders with specific mixed boundary conditions
Authors: Rong D L , Zhou Z H , Xu W , Li H Y , Sun J B , Xu X S 
Published: September 2019

Abstract
A novel analytical symplectic method is introduced to investigate the three-dimensional steady-state heat conduction of cylinders with specific mixed boundary conditions (partial temperature and partial heat flux density). By defining the temperature and heat flux density as the mutually dual variables, the Hamiltonian form of governing equations are established. The original problem is reduced into a symplectic eigenproblem which can be solved by the method of separation of variables and a symplectic sub-system. Exact analytical solution is obtained and expressed in terms of symplectic eigensolutions. Comparison studies demonstrate the accuracy of the proposed method. Some new results are given also.
Nonlinear Dynamical Analysis of a Circular Truss Antenna in Thermal Environments
Authors: Wu Ruiqin , Zhang Wei 
Published: September 2019

Abstract
This paper investigates the nonlinear dynamics of the circular truss antenna with considering the thermal effect. The first-order shear deformation shell theory and the Hamilton’s principle are used to establish the mechanical model for the circular truss antenna system. The motion governing equation is derived for the equivalent circular cylindrical shell. For interest in 1:2:3 internal resonances, the continuous system of nonlinear partial governing differential equation of motion is truncated into a three-degree-of-freedom system of ordinary differential equation including quadratic and cubic nonlinearities. From the averaged equations obtained by the method of multiple scales, numerical simulations are presented to investigate the effects of the thermal excitation on the nonlinear responses of the truss antenna system. Bifurcation diagram, phase portraits, time histories, power spectra and max Lyapunov exponents are used to get the numerically results. It is found that there exist period doubling bifurcations, periodic motions and chaotic motions in the system. The numerical results show that the thermal excitation has significant influence on the nonlinear dynamical behaviors of the circular truss antenna system. The findings in this paper is also useful for the nonlinear vibration control of the shell structure.
Vibration of functionally graded Mindlin plate based on a modified strain gradient elasticity theory
Authors: Jiang Jingnong , Wang Lifeng 
Published: September 2019

Abstract
Vibrational behavior of functionally graded (FG) microplates is investigated by a new modified strain gradient Mindlin plate (MSGMP) model. With the help of Hamilton’s principle, the dynamic equation is easily obtained. Furthermore, the general forms of boundary conditions are gotten by using coordinate transformation. The MSGMP model can be degenerated to a couple stress elastic Mindlin plate model or the classical Mindlin plate (CMP) model. Analytical solutions of vibrational problem of a rectangular microplate with four simply supported edges are gotten. Numerical results reveal significant effects of the dimensionless nonlocal parameters, the power law index and vibration mode on the free vibration behavior of FG plate.
270-degree arc-shaped piezoelectric energy converter in uniflow fluid environment
Authors: Gong Ying , Shan Xiaobiao , Yang Zhengbao , Xie Tao 
Published: September 2019

Abstract
Energy harvesting in uniflow fluid environment aims at ambient energy that can be used in water environment for monitor equipment. In this paper, we focus on coupling both bending vibration and torsional vibration to gain better power generation. A novel structure of energy converter(arc-shaped) was designed and manufactured. Meanwhile the influence of vibrator with and without a pelvic fin was tested. Mathematical analyse due to vibration phenomenon and experimental result are reported. The 270-degree arc-shaped ring size piezoelectric ceramic is verified capable of producing an effective voltage over 10 V with the power of 0.5 mW.
Nonlinear transverse vibration of nano-strings based on the differential type of nonlocal theory
Authors: Wang P Y , Zhu C X , Li C , Li S 
Published: September 2019

Abstract
The nonlinear vibration responses of nano-strings are studied based on the theory of Eringen’s nonlocal elasticity. Firstly, the nonlocal differential constitutive model in one-dimensional form which is suitable for a string structure is used, and then the governing equation of motion for the nonlinear vibration of nano-strings is derived by considering the expression of classical Lagrangian strain. In order to solve the non-dimensional nonlinear governing equation of motion, the Galerkin method or Rayleigh-Ritz method is applied, and the nonlinear partial differential equation is approximately transformed into the a set of ordinary differential equations. The ordinary differential equations are then solved by a numerical method, and the nonlinear vibration responses under different time histories are thus obtained. Subsequently, the approximate numerical solution of the nonlinear displacement is solved by the second-order multi-scale method. The nonlinear phenomena in the transverse displacement and the influences of nonlocal scale parameter on the nonlinear vibration characteristics of nano-strings are analyzed accordingly. The results will provide a basis for understanding and controlling the nonlinear dynamics of nano-strings which may act as key components in the booming intelligent nano-systems.
Vibration Suppression of a Cantilevered Piezoelectric Laminated Composite Plate Subjected to Hygrothermal Loads
Authors: Jiang Yue , Xue Ning , Lu Shufeng , Song Xiaojuan 
Published: September 2019

Abstract
In this paper, the vibration suppression strategy for a cantilevered rectangular piezoelectric laminated composite plate is proposed by using the piezoelectric patches, which are attached to the upper and lower surfaces of the plate as the actuators and sensors, respectively. The main contributions of this study is as follows: Firstly, Based on classical laminated plate theory and considering the action of piezoelectric loadings, the dynamics equation of a piezoelectric laminated composite plate subjected to hygrothermal loads is derived by using Hamilton’s principle. The partial differential equations of the piezoelectric laminated composite plate are discretized to a two-degree-of-freedom control equation by using Galerkin method. Secondly, According to the discrete nominal model, a robust controller for the uncertain systems is proposed. Based on the state space equation, the output feedback controller for the system is designed. In the constructed full-dimensional state observer, the estimated state feedback is introduced to construct a closed-loop feedback system. Using the Lyapunov Matrix Inequality (LMI) method and Lyapunov Stability Theory, the feedback gain matrix and observation gain matrix for the system are designed to make the closed-loop system asymptotically stable. Finally, the accuracy and effectiveness of the controller are verified by numerical simulation.
Temperature and strain-rate dependent constitutive model for prediction of thermal cycling life
Authors: Wang Wenjie , Long Xu 
Published: September 2019

Abstract
With temperature cycling as the characteristic working environment of aerospace electronic chips, various constitutive models have been proposed to predict the failure problems of solder joints. However, most researchers adopted only a set of constant parameters to describe the solder joint material properties throughout the temperature cycles, which is obviously unreasonable concerning the possible wide range of working temperature. In fact, with the changing temperature and strain rate, some material parameters will correspondingly evolve as observed in the experiments. In this paper, the framework of the Anand constitutive model is adopted to verify the effect of material parameters of different temperatures and strain rates on the mechanical properties of materials under the scenario of temperature cycling. The lead-containing solder alloy 63Sn37Pb material that is most widely used in aerospace is selected as the solder material for the interconnection structure. In addition, a typical plastic ball grid array (PBGA) packaging structure is used to analyze the influence of the constitutive model parameters on the PBGA thermal fatigue life. Based on experimental data, seven sets of constitutive model parameters with different temperatures (-55°C~125°C) under a region of low strain rate (1×10-4/s) were employed to compare the mechanical properties of the material under temperature cycling. The sensitivity analysis of material parameters is performed and the underlying mechanism are also explained so that the present study can promote the optimization of the constitutive model in numerical simulations in practice.
Preparation and mechanical properties of steel fiber reinforced high performance concrete with copper slag as fine aggregate
Authors: Li X M , Zou S H , Zhao R G , Deng L Y , Ji N , Ren C L 
Published: September 2019

Abstract
High performance concrete is widely used in constructional engineering for its long durability, excellent volume stability, adequate compressive strength and good construction performance. In this paper, a class of high performance concretes are prepared by using copper slag instead of sand as a fine aggregate, and their mechanical properties are tested. Firstly, the high performance concrete specimens with different copper slag content and the steel fiber reinforced ones are individually prepared. Then, the compressive and flexural strength tests for cured high performance concrete specimens are operated according to the CECS13-2009 fiber reinforced concrete test method standard. The test results show that for the high performance concrete with copper slag as fine aggregate, the compressive strength reaches a peak value as the replacement ratio of copper slag to fine sand about 35%, but the flexural strength decreases with increasing copper slag replacement ratio, while for steel fiber reinforced high performance concrete, when the copper slag replacement ratio is about 40%, the concrete has a relatively high compressive strength, flexural strength and toughness. Furthermore, under an equivalent strength condition, the additional steel fiber improves the replacement rate of copper slag in the high performance concrete, so the steel fiber reinforced high performance concrete with copper slag as fine aggregate exhibits a better comprehensive mechanical property.
Influence of Defects on the Mechanical Performances of Super Carbon Nanotube
Authors: Shi Xian , He Xiaoqiao 
Published: September 2019

Abstract
Although nanotechnology processes greatly in recent years, defects are still unavoidable in the production of CNTs and relevant structures, which remarkably reduce their theoretical high-performance. In this study, the influence of defects on the mechanical and fracture performances of SCNT, a CNT-based honeycomb structure, are investigated via molecular dynamics simulations. Defects are revealed to reduce the bearing capacities of SCNTs and the reducing degree significantly relies on both the defect position and the SCNT structure. Defects also modify the cracking path of SCNTs and slow down the fracture propagation, especially for zigzag SCNT. Essentially, defects bring force concentration near the defective area, resulting in the local early fracture. Yet the force concentration degrees of the armchair and zigzag SCNTs are affected by different mechanisms. The force concentration degree of armchair SCNT is displacement-controlled, but that of zigzag SCNT is determined by the force redistribution. The underlying reason for controlling the influence of defect is found to be the force transfer mode of the armchair and zigzag SCNT. With the fact that defects widely exit in the CNT-based networks, this investigation could provide valuable information for the practical applications of CNT-based structures.
Research on Buckling and Post-buckling Characteristics of Composite Curved Stiffened Fuselage Panel under Hoop Bending load
Authors: Hao C , Nan C Y , Peng Z , Lei L 
Published: September 2019

Abstract
In order to study the buckling, post-buckling and failure modes of composite fuselage structures under circumferential bending loads, innovative four-point bending tests technology was developed and performed on composite curved stiffened fuselage panel (CSFP) specimens with two frame configurations of C-section and Z-section. Meanwhile, the stability engineering analysis and estimation based on plate buckling theory and simplified boundary were carried out, and the finite element (FE) models based on Hashin failure criterion were established to simulate the buckling, post-buckling and failure modes of CSFP specimens. The tests and analysis results show that the buckling modes and failure modes of C-section and Z-section specimens are different under positive bending loads. Specifically, the buckling of C-section specimens firstly occurs in the middle of the frame, then local buckling occurs at both ends of the frame, leading to fracture. For Z-section specimens, only local buckling occurs in the middle of the frame, which directly leads to fracture. By comparing the three methods, the results of FE analysis and engineering calculation are in good agreement with the test results. Among them, the prediction of instability mode and failure mode by FE method is very accurate, and the buckling strain calculated by engineering method can provide a good reference for structural design.
An efficient finite strip procedure for initial post-buckling analysis of composite laminated members
Authors: Ma Pusong , He Bin , Qi Haonan 
Published: September 2019

Abstract
An efficient procedure based on the semi-analytical finite strip method with newly introduced invariant matrices is developed to analyze the initial post-buckling of composite laminated members. The nonlinear strain-displacement equations obtained from the Von-Karman assumption and three plate theories, which are classical thin plate theory, first-order shear deformation plate theory, and high-order shear deformation plate theory can be used to evaluate the initial post-buckling performance of the composite laminated members. According to the principle of the minimum potential energy, the formulations of the finite strip method can be deduced. In order to improve the computational efficiency, the pre-integrated invariant matrices are introduced, which can convert the complicated analytical integral calculation of the stiffness matrix into a relatively simple matrix multiplication calculation. Several benchmark problems are tested based on the proposed method and other conventional methods. The corresponding comparison results show that: (1) the proposed method is proved to be feasible and accurate for those three different theories; (2) compared with the other conventional finite strip methods, the proposed method is much more efficient since it requires the integration of the stiffness matrix only once no matter how many iterations are needed, (3) and the advantage of time-saving is increasingly remarkable as the number of iterations increases.
Fatigue Topology Optimization Based on Global Stress Constraint Method
Authors: Su Peng-Fei , Ye Hong-Ling , Wang Wei-Wei , Sui Yun-Kang 
Published: September 2019

Abstract
In topology optimization design for continuous structure, common mechanical properties considered in optimization model focus on structural strength, stiffness and stability. However, fatigue characteristic of structure is easily ignored, which is one of the main causes of engineering failure. Therefore, it is necessary to consider the fatigue characteristic for the optimization design of the structure. In order to investigate the influence of fatigue on structural topology in optimization design, fatigue life filter function is introduced and then the model and solution method of fatigue topology optimization for continuous structures are proposed based on independent continuous mapping method (ICM). The fatigue topological optimization model is established with structure minimum weight as objective and fatigue life as constraint, and the model is solved by global stress constraint method. The results extend the ICM method and this basic theory provides a new idea for fatigue topology optimization.
Nonlinear dynamics of rotating blades with variable cross-section
Authors: Zhang Wei , Liu Huan , Niu Yan 
Published: September 2019

Abstract
In this chapter, nonlinear dynamic behaviors of the variable cross-section rotating blades are studied. The blade is considered to be a rotating cantilever plate model with variable cross-section. Considering the influence of centrifugal force, variable rotating speed and cross-section warp. In the light of the Hamilton’s principle, the von Karman deformation theory and the third-order shear deformation theory, we can derive the ordinary differential equation by using Galerkin method from the nonlinear partial differential equations. The multiple scales is applied to get the averaged equations with the 1:3 internal resonance of the rotating blades. Using numerical simulation to study the effects of aerodynamic forces and disturbance amplitude of the rotating blades on nonlinear dynamic behaviors. It shows that the rotating blades performs complex nonlinear dynamic behaviors, such as single periodic, chaotic motions, multiple periodic and quasi-periodic.
Numerical prediction of uniaxial tensile properties of 3D braided C/SiC composites
Authors: Hui Xinyu , Wang Haibin , Xu Yingjie , Zhang Weihong 
Published: September 2019

Abstract
This paper is focused on the microstructure modeling and numerical prediction of uniaxial tensile properties of three-dimensional (3D) braided carbon fiber-reinforced silicon carbide (C/SiC) composites. Based on the multiscale characteristics of the fabrication process and component material distribution of 3D braided C/SiC composites, fibre scale and tow scale RVE models were established considering the local periodicity of the microstructure of the composites. Finite element method was applied to predict the elastic properties and strength properties of the fibre scale model, which were then substituted into the tow scale model. The Tsai-Wu failure criterion was employed and the stiffness reduction was conducted in the failed elements according to the different failure modes. The progressive damage process of 3D braided C/SiC composites under uniaxial tensile load was simulated.
Experimental investigation of thermomechanical behaviour of NiTi shape memory alloy under low-velocity impact loading
Authors: Ren Xuanchang , Wang Jun , Xu Yingjie , Zhang Weihong , Zhu Jihong 
Published: September 2019

Abstract
This paper experimentally investigates the thermomechanical behaviour of NiTi shape memory alloy (SMA) under low-velocity impact loading. The phase transformation temperatures of the NiTi material are measured by means of the Differential Scanning Calorimetry (DSC) method. The impact tests are carried out on a drop hammer impact system, wherein force sensor and infrared camera are used to capture the thermomechanical behaviour of NiTi SMA. Several prime material features of SMA, such as superelastic stress-strain response, stress-induced martensitic phase transformation, residual deformation, heat production and energy dissipation, are observed in the drop hammer test of the superelastic NiTi sheet. Considering the impact test is an approximate adiabatic process, the temperature variation on NiTi sheet is highlighted, due to the latent heat and intrinsic dissipation. This temperature variation will affect the mechanical behaviour of SMA, and therefore bring about complex thermomechanical coupling effect in the low-velocity impact test.
Design and Analysis of Multi-layer Integrated Thermal Protection System based on Ceramic Matrix Composite and Titanium Alloy Lattice Sandwich
Authors: Xu Ningxin , Xu Yingjie , Zhang Weihong , Zhu Jihong 
Published: September 2019

Abstract
In order to satisfy the aerodynamic shape requirement of hypersonic vehicles, a curved multi-layer integrated thermal protection system (ITPS) is developed in this paper. The ITPS consists of a ceramic matrix composite layer, a lattice sandwich layer and a glass wool layer. The curved ITPS samples are fabricated. Then experimental test and numerical simulation are carried out respectively to evaluate the heating insulation effect of the ITPS samples. In addition, a series of numerical simulations are conducted to investigate the influences of lattice configuration and gradient layer layout on the heating insulation and load bearing capability of the ITPS.