bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of the anterograde trafficking of GPCRs: Regulation of AT1R transport by interacting proteins and motifs
Authors: Zhang Maoxiang , Wu Guangyu
Published: November 2018

Anterograde cell surface transport of nascent G protein‐coupled receptors (GPCRs) en route from the endoplasmic reticulum (ER) through the Golgi apparatus represents a crucial checkpoint to control the amount of the receptors at the functional destination and the strength of receptor activation‐elicited cellular responses. However, as compared with extensively studied internalization and recycling processes, the molecular mechanisms of cell surface trafficking of GPCRs are relatively less defined. Here, we will review the current advances in understanding the ER‐Golgi‐cell surface transport of GPCRs and use angiotensin II type 1 receptor as a representative GPCR to discuss emerging roles of receptor‐interacting proteins and specific motifs embedded within the receptors in controlling the forward traffic of GPCRs along the biosynthetic pathway.
Prevalence and risk factors for RBC alloantibodies in blood donors in the Recipient Epidemiology and Donor Evaluation Study‐III (REDS‐III)
Authors: Karafin Matthew S. , Tan Sylvia , Tormey Christopher A. , Spencer Bryan R. , Hauser Ronald G. , Norris Philip J. , Roubinian Nareg H. , Wu Yanyun , Triulzi Darrell J. , Kleinman Steve , Gottschall Jerome L. , Hendrickson Jeanne E.
Published: November 2018

BACKGROUND

Little information exists on red blood cell (RBC) alloimmunization in healthy US blood donors, despite the potential significance for donors themselves, blood recipients, and the blood center.

STUDY DESIGN AND METHODS

Donor/donation data were sourced from the Recipient Epidemiology and Donor Evaluation Study‐III, which contains information from four US blood centers during 2012 through 2016. Multivariable logistic regression was used to assess prevalence of positive antibody screen by donor demographics, blood type, parity, and transfusion history.

RESULTS

More than 2 million units were collected from 632,378 donors, with 0.51% of donations antibody screen positive and 0.77% of donors having at least one positive antibody screen. The most common antibody specificities were D (26.4%), E (23.8%), and K (21.6%). Regression analysis indicated that increasing age, female sex, D‐negative status, and history of transfusion and pregnancy were positively associated with a positive antibody screen. Prior transfusion history was most strongly associated with a positive antibody screen, with donors reporting a prior transfusion having a higher adjusted odds ratio (3.9) of having a positive antibody screen compared to donors reporting prior pregnancy (adjusted odds ratio, 2.0). Though transfusion was a more potent immune stimulus for RBC alloantibody formation than pregnancy, the sheer number of previously pregnant donors contributed to pregnancy being a risk factor for the majority of clinically significant RBC alloantibodies detected in females.

CONCLUSION

These findings on prevalence of and risk factors for RBC antibodies may have implications for future medical care of donors and for operations at blood centers.
Evaluation of a new West Nile virus nucleic acid test for screening of blood donations
Authors: Stanley Jean , AuBuchon James P. , Erickson Yasuko , Waxman Dan A. , Williamson Phillip C. , Bertuzis Rasa , Huynh Nancy , Duncan John R. , Dyer Nicole , Pate Lisa L. , Galel Susan A.
Published: November 2018

BACKGROUND

West Nile virus (WNV) is transmitted to humans through mosquito bites and can be further transmitted to humans through transfusion or transplantation. Because most infected individuals are asymptomatic, blood donor screening is important in areas where WNV is endemic. These studies evaluated the performance of a new test for detection of WNV RNA in blood donations.

STUDY DESIGN AND METHODS

Analytical performance evaluation included sensitivity, specificity, inclusivity, and correlation. A clinical specificity study was conducted at four blood donor testing laboratories in parallel with the cobas TaqScreen WNV Test (Roche Molecular Systems, Inc.).

RESULTS

The 95% and 50% limit of detection for cobas WNV was 12.9 copies/mL (95% confidence interval [CI], 10.8–16.3) and 2.1 copies/mL (95% CI, 1.9–2.4) for WNV lineage 1, respectively, and 6.2 copies/mL (95% CI, 4.8–8.9) and 1.1 copies/mL (95% CI, 0.8–1.3) for WNV lineage 2, respectively. Clinical specificity was 100% in 10,823 donor samples tested individually (95% CI, 99.966%–100%) and 63,243 tested in pools of 6 (95% CI, 99.994%–100%). Samples of other members of the Japanese encephalitis virus serocomplex, including St Louis encephalitis, Japanese encephalitis, Murray Valley encephalitis, Usutu, and Kunjin viruses were detected by cobas WNV.

CONCLUSION

The cobas WNV test for use on the cobas 6800/8800 System, a fully automated test system, demonstrated high sensitivity and specificity and is suitable for the detection of WNV in blood donors.
High Proton Conductive Sulfonated Graph Copolyimide Membranes Containing Chemically Stable Naphthalene Moieties
Authors: Yamazaki K. , Tanaka M. , Kawakami H.
Published: November 2018

Syntheses, proton conductivity, gas permeability properties, and membrane stabilities of novel sulfonated graft copolyimides were investigated. The sulfonated graft copolyimide membrane showed significantly high proton conductivity (0.96 S/cm at 90°C and 98%RH, more than 6 times that of Nafion), suggesting that the protons in the sulfonated graft copolyimide membranes were efficiently transported. The oxidative stability of the novel sulfonated graft copolyimide was higher than that of the conventional graft copolyimide because of their polymer structures containing chemically stable naphthalene moieties and non–sulfonated polymer main–chain. Furthermore, the oxygen permeability of the membrane was approximately one–fourth the value of Nafion and had a very excellent gas barrier property. We demonstrated that the graft copolymer membrane could realize high proton conductivity and low gas permeability to have potential applications for use in fuel cells.
Fabrication of Electrospun Membranes based on Poly(caprolactone) (PCL) and PCL/Chitosan Layer by Layer for Tissue Engineering
Authors: Yee Foong Choi , Sultana Naznin
Published: November 2018

Recently, in the field of tissue engineering, fabrication of three-dimensional (3D) electrospun scaffold or membrane is much emphasized. In this study, layered composite scaffolds or membranes were fabricated using two biodegradable polymers, polycaprolactone (PCL) and Chitosan layer-by-layer with multilayer electrospinning method. Characterizations of membranes were done using several techniques. Electrospun composite membrane’s surface morphology was examined using a Scanning Electron Microscopy (SEM) and the wettability of the material’s surface was determined using water contact angle measuring measurement (WCA). Water uptake properties of electrospun membrane were also determined. Using optimized solution concentration and electrospinning processing parameters, the composite PCL/Chitosan and PCL layer-by-layer were successfully fabricated. It was observed from SEM that the composite electrospun membranes produced consisted microfibers and nanofibers within single scaffold. The water contact angle for the double-layered composite electrospun membranes was lower than the pure PCL. The double-layered composite membrane also had higher water uptake properties compared to pure PCL scaffold.
Stability of Palm Oil-based Emulsion Liquid Membrane for Succinic Acid Extraction from Aqueous Solution
Authors: Jusoh N. , Othman N.
Published: November 2018

Emulsion liquid membrane (ELM) process has high potential in the separation of succinic from the fermentation broth. However, the major drawback of this technology is the stability of emulsion globules during the extraction process and the chemical involved in the liquid membrane formulation. This study investigate the stability of ELM using a greener formulation containing Amberlite LA-2 as a carrier, Span 80 and Tween 80 as a surfactant, palm oil as a diluent and sodium carbonate (Na2CO3) as an aqueous stripping agent. The emulsion stability was evaluated by observing the water-oil separation of the emulsion and microscopic image of emulsion droplets count and size. Several operating parameters including the organic to internal ratio, homogenizer speed, homogenizing time, and surfactant concentration, and surfactant blend were investigated. The results show the most stable water-in-oil emulsion was observed at 3:1 organic to internal ratio; 7000rpm homogenizer speed; 5 minute emulsification time; 3% (w/v) surfactant at HLB 8. Besides, the extraction study shows 70% of the succinic acid was extracted at 0.01M Na2CO3, 1:3 treat ratio, and 0.7M Amberlite in palm oil at optimum primary emulsion stability conditions. This indicates the potential of using palm oil based ELM for the extraction of succinic acid.
Desalination Performance of Modified Multiwall Carbon Nanotubes
Authors: Zhang Dengsong , Shil Liyi , Fang Jianhui , Dai Kai
Published: November 2018

Modified multiwall carbon nanotubes (MWCNTs) were used as the electrodes of flow–through capacitor for the desalination, which were cost–cutting, energy–saving, and enviromnent–friendly and could be expected to be an altemative technology for reverse osmosis membrane for sea water desalination. Investigated by transmission electron microscope (TEM) and nitrogen adsorption/desorption for modified MWCNTs, it was confirmed that after modification treatment by immersion in diluted HNO3 solution with ultrasonic and then milling by ball at a high velocity, the metal catalyst particles at the tip of MWCNTs disappeared, the MWCNT length became short, the cap at the tip of nanotube was opened, the internal surface area could be effectively used, leading to the increase of the specific surface area and pore volume, and thus MWCNTs modified by that method had the best desalination performance. This modification technique is simple and the efficiency is high.
The Study of Carbon Dioxide Removal in Membrane Module by Single and Mixture of Alkanolamine Aqueous Solutions
Authors: Kasim N. , Aroua M. K. , Sulaiman N. M.
Published: November 2018

This work presents an investigation on the performance of CO2absorption into aqueous alkanolamine solution using a hollow fiber membrane gas–liquid contactor. Aqueous solution of ethanolamine (MEA), diethanolamine (DEA), 2–amino–2–methyl–1–propanol (AMP) and piperazine anhydrous (PZ) were chosen as the absorption liquids. A microporous hollow fiber membrane made of polyvinylidene fluoride (PVDF) was used as the medium for gasliquid absorption process. In this study, the operating temperature is fixed at 30°C, while the flowrate of CO2 and alkanolamine were in the range of 1000–5000 ml/min and 50–280 ml/min respectively. The feed gas was introduced directly to the shell of the module at 1–1.5 bar and the liquid flowed through the fiber lumen side. The CO2 transfer through the membrane was found to be reaction controlled and dependent on the type of amine used. The use of piperazine as an accelerator in the mixture of the absorption liquids gives a good impact on increasing the performance for the rate of CO2 transfer.
Influence of Surface Modifying Macromolecules (SMMs) on Polyethersulfone Hollow Fiber Membranes for Water Separations
Authors: Bolong N. , Ismail A. F. , Salim M. R. , Rana D. , Matsuura T.
Published: November 2018

The objective of this work is to modify the polyethersulfone (PES) hollow fiber membranes by blending with Surface Modifying Macromolecules (SMMs) which were able to introduce charges at the membrane surface. To study the effects of SMMs, PES solutions with and without blending SMMs were spun by the dry–wet phase inversion method. The membranes were characterized by ionic solutes permeation and Field Emission Scanning Electron Microscopy (FESEM). There was no significant difference in the membrane morphology between the membranes with and without SMM blending, indicating that the morphology of the base polymer remained relatively unchanged. However, based on Energy Dispersive X–ray (EDX) analysis, the presence of SMM’s elements at the surface of the SMM blended membranes was detected. The pure water permeation rates were found two times increased with the existence of SMMs, while rejection towards ionic solutes remained relatively unchanged.
Organic Foulants Characteristics in Membrane Bioreactor
Authors: Aryal R. K. , Vigneswaran S. , Lebegue J. , Shon H. K. , Kandasamy J. , Heran M. , Grasmick Alain
Published: November 2018

A laboratory scale side stream membrane bioreactor system with flat sheet membrane was operated for 5–days run at three different aeration rates (100, 200 and 300 L/h). The organic foulants deposited on the membrane surface was studied after extraction with 5% NaOH solution using three spectroscopic techniques. The IR spectra showed no distinct similarity in peaks among the three. The fluorescence spectra showed increase of soluble microbial products in foulant with decrease of aeration rate. This was supported by the size exclusion chromatography in which biopolymers concentration in fouling decreased with increasing aeration rate.
Adhesion of Partially and Fully Collapsed Nanotubes
Authors: Li Ming , Li Hao , Li Fengwei , Kang Zhan
Published: November 2018

The competition between the structural rigidity and the van der Waals interactions may lead to collapsing of aligned nanotubes, and the resulting changes of both configurations and properties promise the applications of nanotubes in nano-composites and nano-electronics. In this paper, a finite-deformation model is applied to study the adhesion of parallel multiwall nanotubes with both partial and full collapsing, in which the noncontact adhesion energy is analytically determined. The analytical solutions of both configurations and energies of collapsed nanotubes are consistent with the molecular dynamics (MD) results, demonstrating the effectiveness of the finite-deformation model. To study the critical conditions of generating the partially and fully collapsed multiwall nanotubes, our analytical model gives the predictions for both the geometry- and energy-related critical diameters, which are helpful for the stability analysis and design of nanotube-based nano-devices.
Detection of Directivity of Fluorescence From a Mixed Specimen Which Consists of Micro Particles Attached Different Fluorescent Substances Using a Light Waveguide Incorporated Optical TAS
Authors: Ohkubo Toshifumi , Terada Nobuyuki , Yoshida Yoshikazu
Published: November 2018

A resin-based optical total analysis system (O-TAS) which consists both of microfluidic channels and light waveguides [1] is thought to be one of the most promising components in developing a “ubiquitous human healthcare system” in the near future. Along with this technology trend, we have already developed a transparent epoxy-resin-based optical TAS chip which has a specially prepared light waveguide structure of radially arranged configuration at an intersection portion with a microfluidic channel, in order to detect directivity of fluorescence from fluorescent substance attached micro particles [2],[3]. Schematic diagram of the optical TAS is shown in Figure 1. In the latest research, utilizing an AC modulated laser source and time-series averaging function on detected signal waveforms, we could have successfully obtained directivities of fluorescence from 5-μm-diameter particles with higher signal to noise (S/N) ratio [3].
Vibration Analysis of Bracket for Vehicle Components
Authors: Kim Dongjoon , Park Chulwoo , Park No-Cheol , Park Young-Pil
Published: November 2018

As automobile is exposed to continuous external forces such as road noise and engine vibration, it is necessary to evaluate vehicle components’ vibration durability at the initial design stage. Fatigue failure is one of the frequent failure mechanism occurred in mechanical components when cyclic loading is applied to subject. Fatigue analysis can be classified into two types; quasi-static fatigue analysis dynamic fatigue analysis considering structural resonance. As the tested bracket’s first natural frequency existed in the requirement spec for vibration test (10∼50 Hz) so dynamic fatigue analysis should be performed. In this study, vibration analysis was carried out in advance of fatigue analysis. Improving design based on the experiments is inefficient and takes a lot of time and money, so finite element model was constructed. From single components to assembly, modal test was performed and verified the finite element (FE) model within 10% error. Also, boundary conditions were determined using beam elements. After FE model construction, vibration analysis was performed using harmonic analysis. The cause of the failure was analyzed based on simulation results.
Numerical Analysis of Vibration Characteristics of Ultra-High Speed Maglev Train With Flexible Car Body
Authors: Ha Hue , Park Kyoung-Su
Published: November 2018

Conventional trains have used wheels while driving because of the friction between the rail and the wheels. However, the conventional train can’t drive fast. In contrast magnetic levitation (maglev) train can speed up to 600km/h. Because of driving so fast there are some vibrations on the car bodies. In this paper, we used multi-body dynamic analysis, ANSYS MAXWELL for determining magnetic forces and integrated with the MATLAB.
Development of Active Aerodynamic Improvement Devices for Automobiles
Authors: Lee SangWook
Published: November 2018

Study on the steady blowing system using state-of-the-art of Computational Fluid Dynamics (CFD) technique based on an open domain CFD software, OpenFOAM[1], is performed to reduce vehicle aerodynamic drag. Realistic vehicle model, DrivAer[2], is used for the validation of current CFD technique. Both the aerodynamic drag coefficient and the surface pressure distributions were compared between current CFD and reference wind tunnel test. It was found that CFD method used in this study is reliable tool for the forecasting of the aerodynamic drag coefficient.

The influence of steady blowing from the sharp edge of the roof end is investigated based on DrivAer Estate back model. Parametric study was performed by changing blowing speed at the three different Reynolds number. It was shown that the steady blowing leads around 3% drag reduction by enhancing wake balance especially, reinforcing downwash flow from the roof.

Therefore it would be concluded that steady blowing is a useful device to reduce aerodynamic drag of automobile.
A Novel Electromagnetic Targeting System Using Rotating Magnetic-Flux Concentration Method for Navigating Endo-Bronchoscopy
Authors: Chen Chin-Chung , Lin Ching-Kai , Cheng Yun-Chien , Chang Chen-Wei , Tsai Sung-Lin , Chen Jia-En , Chung Tien-Kan
Published: November 2018

In this paper, we proposed a novel electromagnetic targeting system using rotating magnetic-flux concentration method for navigating endo-bronchoscope. This system consists of a magnetic-flux emitting coil, a magnetic-flux receiving electromagnets-array, a 2D model of bronchial tree, the magnetic-flux concentrator embedded on brush-guiding tube which was connected to the guide sheath. When the concentrator in the 2D bronchial tree passes through the air gap between the emitting coil and the receiving electromagnets-array, the concentrator concentrates the magnetic flux between the coil and the array. The concentrated magnetic flux is subsequently received by the receiving electromagnets-array and thus stable voltage output is produced. Furthermore, when the concentrator is rotated, the concentration of the magnetic flux is periodically changed and thereby the voltage output is periodically changed. By analyzing the voltage changes, the location of the concentrator (as well as guide tube and sheath) is targeted. According to the experimental results, the system successfully targets the location of the guide sheath in the 2D model of bronchial tree.
Development of a Luminal Esophageal Temperature Monitoring Device for Use During Treatment for Atrial Fibrillation
Authors: Garner Scott , Morris Karcher , Pegan Raul , Savides Thomas , Talke Frank E.
Published: November 2018

Luminal esophageal temperature monitoring is of high importance during catheter ablation surgeries of the left atrium. A device is currently under development to accurately measure temperature of the inner esophageal wall. Ex vivo tests using porcine esophageal and left atrial tissue have been set up and performed to better understand heat flow through the biomaterials in contact. To compliment ex vivo experiments, a numerical analysis using thermal finite element analysis has been implemented to compliment ex vivo experiments with a numerical study of the temperature distribution across tissue layers as a function of tissue thickness, as well as heat source contact size and time. Both the ex vivo experiments and finite element simulations aid in development of a practical prototyped device for potential use during catheter ablations.
Investigation of Flexible Magnetic Medium Microstructure Behavior Under Implementation of Roller Leveling Process
Authors: Chen Brian , Chang Jen-Yuan (James)
Published: November 2018

The aim of this paper is to investigate the effect of roller leveling process on the behavior of microstructure in flexible magnetic medium. Linear magnetic encoder is a highly precise measuring device that required accurate quality control during manufacturing. Previous studies have demonstrated the feasibility of roller leveling application to enhance the manufacturing of flexible magnetic medium. Mechanical shape defects in magnetic medium occurred during manufacturing due to environmental conditions can be eliminated through roller leveling process. In this paper, further steps were taken to understand the effect of roller leveling process in the microstructural level. From experimental results, it demonstrates that roller leveling process, a type of cyclic loading process, would not encourage crack growth if cracks were not initiated prior to leveling process. In addition to removing mechanical shape defects, understanding roller leveling process in magnetic medium application through investigating microstructure behavior has implications toward the fabrication quality of flexible magnetic medium.
Impact of Shallow Void Corrosion on HDD Initialization Failures
Authors: Srivastava Abhishek , O’Dell Tom , Boszormenyi Istvan
Published: November 2018

This paper investigates how corrosion growth that originates from shallow film voids on thin film sputtered magnetic media can impact the final HDD system performance. The impact of shallow void corrosion [1] in HDD system can be both on its behavior during initialization i.e. servo write formatting and initial defect mapping, and on its long term reliability. One of the main concerns for HDD reliability due to media is the occurrence of a condition called metallic smear. Metallic smear is a contamination of the head-pole area that causes an unstable fly height condition. Metallic smear is possibly caused by media corrosion and therefore void corrosion is a logical concern. However, our study shows that shallow void corrosion is not associated with metallic smear risk and does not contribute to HDD initialization failures.
A Piezoelectric Metamaterial With Bistable Circuit Shunts for Adaptive Non-Reciprocal Elastic Wave Transmission
Authors: Zheng Yisheng , Wu Zhen , Zhang Xinong , Wang K. W.
Published: November 2018

In this paper, we present a piezoelectric metamaterial integrated with bistable circuits to realize adaptive non-reciprocal elastic wave transmission. Dynamics of the bistable circuit and the piezoelectric metamaterial are investigated numerically to analyze the wave transmission characteristics of the proposed system. Results reveal that when the excitation amplitude exceeds certain threshold, wave energy is able to propagate even with excitation frequency inside the local-resonance bandgap of the piezoelectric metamaterial. This bandgap transmission phenomenon is also known as supratransmission. It is shown that by introducing spatial asymmetry, the system could exhibit different supratransmission thresholds when it is actuated in opposite directions, and hence there exists an excitation range within which wave energy is only able to propagate in one direction. Furthermore, this excitation range to facilitate non-reciprocal energy transmission is adaptable by adjusting the stable equilibria of the bistable circuits, which can be conveniently tuned utilizing only DC voltage sources. Additionally, it is shown that by adjusting the stable equilibria, the wave propagation direction, analogous to the forward direction of an electrical diode, can be easily reversed. Lastly, in contrast to many nonlinearity enabled non-reciprocal systems, the proposed system is able to realize non-reciprocal elastic energy transmission with majority of the transmitted energy preserved at the original input frequency. Overall, these results illustrate a new means of utilizing nonlinear piezoelectric metamaterial to manipulate elastic wave transmission.
Design and Experimental Study of a Bioinspired Wall-Climbing Robot With Multi-Locomotion Modes
Authors: Xu Linsen , Liu Jinfu , Xu Jiajun , Wu Xuan , Fan Shengyao
Published: November 2018

In this article, a novel wall-climbing locomotion mechanism, which can adapt multiple wall surfaces is developed to imitate the special animals, such as geckoes or flies. The spiny and adhesive belts are adopted in this robot to implement climbing on different kinds of wall surfaces instead of the vacuum generator for moving quietly and quickly. The switching mechanism is brought out to realize the belts switching between different surfaces, and a tail made up of two torsional springs and a supporting part is designed to overcome the robot’s overturning moment. So the mechanical system of the robot consists of four parts: the power and drive system, the moving mechanisms (spiny and adhesive), the switching system and the tail. Then the virtual prototyping of the robot with multi-locomotion modes is brought out, and the different gaits on the rough surface, the smooth surface and the transition process are analyzed. During the spine gait using the spine belts, the adhesive force should overcome the robot gravity and drive it, so the drive torque can obtained by building the force balance equations of the robot, which include the supporting forces of the spine belts and the tail. During the adhesive gait using the adhesive rubber belts, the force balance equations should include the supporting forces of the adhesive belts and the tail. And during the transition gait, the force balance equations include all of the above forces. So the mechanical model of the robot can be built according to the above analysis. Finally, the experimental prototype of the wall-climbing robot is manufactured and the wall-climbing experiments are carried out to testify its functions. The experiments show that the robot can adapt to different wall surfaces, and the torque parameters obtained based on the dynamics model can ensure the robot to locomote stably.
Practical Considerations for Sliding Mode Observers for High-Rate Structural Health Monitoring
Authors: Joyce Bryan , Dodson Jacob , Hong Jonathan , Laflamme Simon
Published: November 2018

Structural health monitoring (SHM) of high-rate, mechanical systems in dynamically harsh environments presents many challenges over traditional SHM applications. Damage in these systems must be detected and quantified in tens to hundreds of microseconds in order to have sufficient time to react and mitigate damage. The computation speeds and robustness of sliding mode observers (SMOs) for state, parameter, and disturbance estimation for linear and nonlinear systems make them an attractive approach for real-time SHM of high-rate systems. This paper investigates a novel SMO combined with a recursive least squares parameter estimator to detect and track changing system parameters. The observer is simulated on a one degree-of-freedom system with time-varying model parameters to mimic damage. This paper focuses on practical considerations for SMOs for high-rate systems, such as the effects of measurement noise and sampling rates on the estimator’s accuracy and convergence speeds.
Structural Design of a Multifunctional Morphing Fowler Flap for a Twin-Prop Regional Aircraft
Authors: Rea Francesco , Amoroso Francesco , Pecora Rosario , Noviello Maria Chiara , Arena Maurizio
Published: November 2018

In the framework of Clean Sky 2 Airgreen 2 (REG-IADP) European research project, a novel multifunctional morphing flap technology was investigated to improve the aerodynamic performances of the next Turboprop regional aircraft (90 passengers) along its flight mission. The proposed true-scale device (5 meters span with a mean chord of 0.6 meters) is conceived to replace and enhance conventional Fowler flap with new functionalities. Three different functions were enabled: overall airfoil camber morphing up to +30° (mode 1), +10°/−10° (upwards/downwards) deflections of the flap tip segment (mode 2), flap tip “segmented” twist of ±5° along the outer flap span (mode 3). Morphing mode 1 is supposed to be activated during take-off and landing only to enhance aircraft high-lift performances and steeper initial climb and descent. Thanks to this function, more airfoil shapes are available at each flap setting and therefore a dramatic simplification of the flap deployment system may be implemented. Morphing modes 2 and 3 are enabled in cruise and off-design flight conditions to improve wing aerodynamic efficiency.

The novel structural concept of the three-modal morphing Fowler flap (3MMF) was designed according to the challenges posed by real wing installation issues. The proposed concept consists of a multi-box arrangement activated by segmented ribs with embedded inner mechanisms to realize the transition from the baseline configuration to different target aero-shapes while withstanding the aerodynamic loads. Lightweight and compact actuating leverages driven by electromechanical motors were properly synthesized to comply with stringent requirements for real aircraft implementation: minimum actuating torque, minimum number of motors, reduced weight, and available design space. The methodology for the kinematic design of the inner mechanisms is based on a building block approach where the instant center analysis tool is used to preliminary select the locations of the hinges’ leverages. The final geometry of the inner mechanisms is optimized to maximize the mechanical advantage as well as to provide the kinematic performances required by the three different morphing modes. The load-path was evaluated, and the cross-sectional size of leverages was subsequently optimized. Finally, actuating torques predicted by instant center analysis were compared to the calculated values from finite element analysis. The structural sizing process of the multi-box arrangement was carried out considering elementary methods, and results were compared with finite element simulations.
A Piezocomposite Trailing-Edge for Subsonic Aircraft
Authors: Wright Cody , Bilgen Onur
Published: November 2018

This paper examines the feasibility of piezocomposite morphing airfoils and trailing edge control surfaces subjected to large dynamic pressures. Piezocomposite airfoils have been shown to be feasible on small unmanned aerial vehicles, subject to relatively low dynamic pressures, operating in the Reynold’s number range of 50k to 250k. The operating range of interest in this paper has a cruising Reynold’s number range between 250k and 1M subject to relatively large wing loading. This range of Reynold’s numbers has not been explored in detail due to the large aerodynamic loads produced. Based on the authors’ previous research on small unmanned aircraft, the proposed concept is a variable-camber airfoil that employs a continuous inextensible surface and surface-bonded piezocomposite actuators. To achieve camber-morphing, multiple piezocomposite actuating elements are applied to the upper and lower surfaces. A case study is performed to determine the design parameters of the airfoil. The parameters to be varied include the substrate thickness of the baseline airfoil, leading edge, and piezocomposite bonded areas. In addition, the positions of the piezocomposites are varied. The analysis is performed using a coupled fluid-structure interaction model assuming static aeroelastic behavior. A voltage sweep is conducted on each airfoil design while being subjected to 70 m/s free stream velocity. The sweep examines the lift coefficient and lift-to-drag ratio of the airfoil over the full operational range. This research lays the groundwork for determining the feasibility of piezocomposite morphing airfoil and trailing edge concepts for use in applications subject to large dynamic pressures.
A Multi-Point Loaded Piezocomposite Beam: Modeling of Vibration Energy Harvesting
Authors: Sharghi Hesam , Bilgen Onur
Published: November 2018

Energy harvesting from ambient vibrations and mechanical deformations using piezoelectric materials has received significant attention over the last decade. These types of energy harvesters find applications in structural health monitoring, wireless sensor networks, etc. In this paper, vibration energy harvesting from piezocomposite beams with unconventional boundary conditions is investigated. The so-called inertial four-point boundary condition is useful in applications where the cantilevered beam setup leads to non-uniform stress-strain distribution along the beam domain. In this paper, the Euler-Bernoulli beam theory is used to model the beam. The voltage output, maximum power output, and the tip velocity are investigated. The efficiency of the four-point loaded beam is compared to a cantilever beam.
Pressure-Driven Morphing Devices for 3D Shape Changes With Multiple Degrees-of-Freedom
Authors: Vasista Srinivas , Riemenschneider Johannes , Mendrock Torsten , Monner Hans Peter
Published: November 2018

Early research on a new concept for a morphing system based on unit structures or cells containing pressurized fluid is presented in this article. The motivation stems from the desire to achieve 3D smooth variations with multiple degrees of freedom and variations in surface area. Such a cell is composed of a hybrid between elastomeric material and stiffening material, creating an orthotropic system. When connected in a network of cells, the morphing system is highly integrated in terms of the components of the skin, substructure and actuation means. Numerical predictions of small simple prismatic cells show a force and axial strain capability of above 200 N and 14% respectively for typical elastomeric and stiffening materials at 8 bar pressure. PolyJet™ additively-manufactured models of wings show how such actuators can be integrated into aircraft structures, including when 3D geometry is highly challenging. These additively-manufactured models were operated at low pressures in the order of 0.5 bar, and a number of open questions on the design, manufacture and operation of such structures are discussed along with intended future work towards higher grade materials and working pressures.
Application of the Maximum Entropy Method to Multifunctional Materials for Data Fusion and Uncertainty Quantification
Authors: Gao Wei , Oates William S. , Miles Paul R. , Smith Ralph C.
Published: November 2018

Bayesian statistics is a quintessential tool for model validation in many applications including smart materials, adaptive structures, and intelligent systems. It typically uses either experimental data or high-fidelity simulations to infer model parameter uncertainty of reduced order models due to experimental noise and homogenization of quantum or atomistic behavior. When heterogeneous data is available for Bayesian inference, open questions remain on appropriate methods to fuse data and avoid inappropriate weighting on individual data sets. To address this issue, we implement a Bayesian statistical method that begins with maximizing entropy. We show how this method can weight heterogeneous data automatically during the inference process through the error covariance. This Maximum Entropy (ME) method is demonstrated by quantifying uncertainty in 1) a ferroelectric domain structure model and 2) a finite deforming electrostrictive membrane model. The ferroelectric phase field model identifies continuum parameters from multiple density functional theory calculations. In the case of the electrostrictive membrane, parameters are estimated from both mechanical and electric displacement experimental measurements.
Hybrid Skin Design of the Transition Region Between Morphing Wing and Fixed Wing
Authors: Radestock Martin , Falken Alexander , Riemenschneider Johannes , Kintscher Markus
Published: November 2018

The adaptation of a wing contour is important for most aircraft, because of the different flight states. That’s why an enormous number of mechanisms exists and reaches from conventional slats and flaps to morphing mechanisms, which are integrated in the wing. Especially integrated mechanisms reduce the number of gaps at the wing skin and produce less turbulent flow. However these concepts are located at a certain section of the wing. This leads to morphing and fixed wing sections, which are located next to each other. Commonly, the transition between these sections is not designed or a wing fence is used. If the transition is not designed, the wing has a step with an activated morphing mechanism and that produces additional vortices. A new skin design will be presented in order to smooth the contour between a fixed wing and a morphing wing. Here the transition between a droop nose and a fixed wing is considered. The skin material is a mix of ethylene propylene diene monomer rubber and glass-fiber reinforced plastic. The rubber is the baseline material, while the glass-fiber is added as stripes in chord-wise direction. In span-wise direction the glass fiber is connected with the rubber. The rubber carries the loads in span-wise direction and reduces the required actuation force. The glass fiber stiffens the skin locally in chord wise direction and keeps the basic contour of the skin. Some geometrical parameters within the skin layup can be varied to change the transition along the span or to reduce the maximum strain within the skin. The local strain maximum is a result of the material transition with different modules. One design of a leading edge was manufactured with an existing mold and it has a span of 200 mm. There are two essential aspects from a structural point of view. One is a nearly continuous deformation along the span and the second is the maximum strain in the rubber. Both aspects are investigated in an experiment and the results are compared with a simulation model. The results show a reliable concept and its numerical model, which will be assigned to a full scale demonstrator. This demonstrator will have a span of 1000 mm and will show the smooth skin transition between a droop nose and a fixed wing.
Nonlocal Modeling and Behavior of Carbon Nanotube-Based Sensors in Thermal Environment
Authors: Ghaffari Seyedeh Sepideh , Ceballes Samantha , Abdelkefi Abdessattar
Published: November 2018

An exact solution that investigates the pre-buckling characteristics of nonlocal carbon nanotube (CNT)-based mass sensor subjected to thermal load under clamped-clamped boundary condition is determined. The uniform temperature rise is utilized to study thermal effects on the sensitivity of the mechanical resonator in pre-buckling configuration. Using Eringen’s nonlocal theory, along with the Hamilton’s principle, the governing equations considering small scale and geometric nonlinearity are derived. The influences of important parameters including nonlocal parameter, temperature change, length, and diameter of the CNT on the pre-buckling behavior and frequency shift of the CNT-based mass detector are also studied. Results show that these parameters have significant impact on the dynamic characteristics of the CNT-mass sensor.
Transient Motion of a Piezoelectrically-Actuated Bistable Beam
Authors: Zarepoor Masoud , Bilgen Onur
Published: November 2018

Bistable structures have several applications in different areas, such as aircraft morphing wings, morphing wind turbine blades, and vibration energy harvesting, due to their unique properties. Bistable structures can be used in morphing wings and wind turbine blades since they are able to alleviate large loads by snapping from one stable position to the other one. A piezoelectric actuator can be used to bring the bistable structure back to its original position after the load is alleviated. In this paper, the transient response of a piezoelectrically actuated bistable beam is investigated experimentally for different force inputs. The goal of these experiments is to explore the ability of a commercial piezoelectric actuator to induce snap-through motion in a bistable structure. The feasibility of performing snap-through motion, and the required energy are found for different excitation force amplitudes and frequencies.
Electrical Properties of Additively Manufactured Acrylonitrile Butadiene Styrene/Carbon Nanotube Nanocomposite
Authors: Thaler Dominic , Aliheidari Nahal , Ameli Amir
Published: November 2018

Additive manufacturing is an emerging method to produce customized parts with functional materials without big investments. As one of the common additive manufacturing methods, fused deposition modeling (FDM) uses thermoplastic-based feedstock. It has been recently adapted to fabricate composite materials too. Acrylonitrile butadiene styrene (ABS) is the most widely used material as FDM feedstock. However, it is an electrically insulating polymer. Carbon Nanotubes (CNTs) on the other hand are highly conductive. They are attractive fillers because of their high aspect ratio, and excellent mechanical and physical properties. Therefore, a nanocomposite of these two materials can give an electrically conductive material that is potentially compatible with FDM printing.

This work focuses on the investigation of the relationships between the FDM process parameters and the electrical conductivity of the printed ABS/CNT nanocomposites. Nanocomposite filaments with CNT contents up to 10wt% were produced using a twin-screw extruder followed by 3D printing using FDM method. The starting material was pellets from a masterbatch containing 15 wt% CNT. Compression-molded samples of ABS/CNT were also prepared as the bulk baselines. The effects of CNT content and nozzle size on the through-layer and in-layer electrical conductivity of the printed nanocomposites were analyzed.

Overall, a higher percolation threshold was observed in the printed samples, compared to that of the compression-molded counterparts. This resulted in the conductivity of the printed samples that is at least one order of magnitude lower. Moreover, at CNT contents up to 5 wt%, the in-layer conductivity of the printed samples was almost two orders of magnitudes higher than that in the through-layer direction. In ABS/3 wt% CNT samples, the through-layer conductivity continuously decreased as the nozzle diameter was decreased from 0.8 mm to 0.35 mm. These variations in the electrical conductivity were explained in terms of the CNT alignment, caused by the extrusion process during the print, quality of interlayer bonding during deposition, and the voids created due to the discrete nature of the printing process.
Optimum Study of Power Efficiency of a THUNDER Harvester
Authors: Hasan Md Nahid , Wang Shang , Arab Ali , Wang Fengxia
Published: November 2018

A piezoelectric-coupled finite element model for a THUNDER harvester (THin layer UNimorph DrivER) is developed and studied in this work. THUNDER is a curved piezoelectric energy generator developed by NASA Langley Research Center, which has better vibration absorption and higher energy recovery efficiency at low-frequency vibration compared to a flat PZT harvester. To apprehend the piezoelectric effect of the THUNDER harvester, finite element method was used to perform the piezoelectric coupled field analysis. Piezoelectric THUNDER harvester was studied under cantilever boundary condition. In the model, the excitation forces are distribution force allied on the top of the dome line. An electric circuit element was used to create load resistance across the electrodes to obtain the generated voltage and power. The effect of the geometric parameter was investigated via the varying radius of curvature, which affects the resonance frequency, voltage, and power output of the THUNDER. Good agreement between finite element analysis and experimental results were also observed. In finite element analysis: Modal analysis was carried out to find the resonance frequency at which maximum performance characteristics of the THUNDER can be achieved. Then, the harmonic analysis was performed to distinguish the voltage and power output variation as the load resistance changes. The effects of the varying radius of curvature on the power efficiency of the THUNDER were summarized.
Parametric Testing of Surrogate Knee Replacement Bearings With Embedded Piezoelectric Transducers
Authors: Carlson Justin , Tiberi Zachariah , Safaei Mohsen , Ponder Robert I. , Anton Steven R.
Published: November 2018

In the United States, Total Knee Replacement (TKR) is a surgery many people go through, but frequently, patients find that they are unhappy post-surgery due to misalignment and loosening of the knee. An estimated 20% of knee replacement recipients report discomfort or undesired functionality within their first few years after surgery. Surgical techniques currently rely heavily on experience and tactile feedback to correctly align the knee replacement. If surgical teams were to have access to data regarding compartmental forces within the knee over the life of the implant, then a more precise balancing procedure could be implemented. As it stands, the only way to obtain this in vivo data is for patients to undergo post-operative fluoroscopy procedures; unfortunately, patients have no incentive to undergo this process. This study tests the capabilities of knee bearings embedded with piezoelectric transducers to estimate the magnitude and location of loading given certain inputs. The prototype is fabricated from ultra high molecular weight (UHMW) polyethylene using Computer Numerical Control (CNC) machining. For this study, to simulate loads under both normal and irregular knee positions, a custom fixture is designed and fabricated for use in a uniaxial load frame. The problem at hand necessitates a more realistic knee testing environment that can simulate the loading types of both balanced and imbalanced knees. Thus, the fixture permits various degrees of internal and external rotation. Additionally, through use of an X-Y translational table, the setup allows for in-plane translation between the condyles of the femoral component and the bearing prototype. This study compares values of force location from the piezoelectric sensors to measurements from pressure sensitive film. The piezoelectric knee bearing is tested to lay the groundwork for in vivo testing. Future work expanding upon this research would include designing and optimizing an in vivo knee bearing replacement to facilitate force location and magnitude data collection in a system free from external power sources by utilizing the energy harvesting capabilities of piezoelectrics.