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Takahashi T.T.,Aerospace and Mechanical Engineering | Takahashi T.T.,Arizona State University | Wood D.L.,Ira A. Fulton Schools of Engineering | Wood D.L.,Arizona State University | Bays L.V.,DragonFly Aeronautics LLC
17th AIAA Aviation Technology, Integration, and Operations Conference, 2017 | Year: 2017

This second paper, in a series, explores technical factors that control “certified” takeoff and landing distances obtainable by modern commercial aircraft. Government regulations control the formulation of field length requirements used by manufacturers and operators. To date, the aviation community considers these regulations adequate. This work seeks to clarify ambiguities within both basis data and regulations that can result in large variations between estimated and actual performance. Here, we explore the effects of well-regulated parameters arising from aerodynamic and propulsive data (the stall speed, stick-pusher settings, and minimum control speed) upon distances. We find small and expected sensitivities associated with changes in thrust, drag, maximum lift coefficient and minimum control speeds. We find significant performance sensitivities arising from the aircraft braking system; the effectiveness of the brakes substantially impacts the choice of decision speed and the resulting takeoff distance. © 2017 T.T. Takahashi, D.L. Wood and L.V. Bays.


Wood D.L.,Ira A. Fulton Schools of Engineering | Wood D.L.,Arizona State University | Takahashi T.T.,Aerospace and Mechanical Engineering | Takahashi T.T.,Arizona State University | Bays L.V.,DragonFly Aeronautics LLC
17th AIAA Aviation Technology, Integration, and Operations Conference, 2017 | Year: 2017

Field performance is primarily a function of forces acting on an aircraft and its ability to achieve flight speed. It is also subject to variability from the introduction of human factors. While physical effects are easily calculated, pilot techniques used during the transition to flight or during an aborted take-off must be modelled using stochastic principles. Regulations set forth by the FAA help engineers design aircraft and determine certified field performance. Other FAA regulations lay out how commercial air carriers must handle airfield operations; however much is left open to interpretation. In order to shed some light on commonly used procedures, we polled commercial pilots on techniques they actually use. We also observed advanced student pilots flying a CRJ-200 simulator during normal and emergency situations. The results were quite diverse; and illuminate many inconsistencies in procedure that results in a wide variation in performance. © 2017 D.L. Wood, T.T. Takahashi, L.V. Bays.


Tate T.H.,University of Arizona | Mcgregor D.,Aerospace and Mechanical Engineering | Barton J.K.,University of Arizona
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2017

The optical design for a dual modality endoscope based on piezo scanning fiber technology is presented including a novel technique to combine forward-viewing navigation and side viewing OCT. Potential applications include navigating body lumens such as the fallopian tube, biliary ducts and cardiovascular system. A custom cover plate provides a rotationally symmetric double reflection of the OCT beam to deviate and focus the OCT beam out the side of the endoscope for cross-sectional imaging of the tubal lumen. Considerations in the choice of the scanning fiber are explored and a new technique to increase the divergence angle of the scanning fiber to improve system performance is presented. Resolution and the necessary scanning density requirements to achieve Nyquist sampling of the full image are considered. The novel optical design lays the groundwork for a new approach integrating side-viewing OCT into multimodality endoscopes for small lumen imaging. KEYWORDS: © 2017 SPIE.


Home > Press > CWRU researchers make biosensor 1 million times more sensitive: Advance aims at detecting cancers earlier, improving treatment and outcomes Abstract: Physicists and engineers at Case Western Reserve University have developed an optical sensor, based on nanostructured metamaterials, that's 1 million times more sensitive than the current best available--one capable of identifying a single lightweight molecule in a highly dilute solution. Their goal: to provide oncologists a way to detect a single molecule of an enzyme produced by circulating cancer cells. Such detection could allow doctors to diagnose patients with certain cancers far earlier than possible today, monitor treatment and resistance and more. "The prognosis of many cancers depends on the stage of the cancer at diagnosis" said Giuseppe "Pino" Strangi, professor of physics at Case Western Reserve and leader of the research. "Very early, most circulating tumor cells express proteins of a very low molecular weight, less than 500 Daltons," Strangi explained. "These proteins are usually too small and in too low a concentration to detect with current test methods, yielding false negative results. "With this platform, we've detected proteins of 244 Daltons, which should enable doctors to detect cancers earlier--we don't know how much earlier yet," he said. "This biosensing platform may help to unlock the next era of initial cancer detection." The researchers believe the sensing technology will also be useful in diagnosing and monitoring other diseases as well. Their research is published online in the journal Nature Materials. It was a terrific teamwork, Strangi said. He worked with postdoctoral researchers Kandammathee Valiyaveedu Sreekanth and Efe Ilker, PhD students Yunus Alapan and Mohamed ElKabbash, Assistant Professor of Physics Michael Hinczewski, Assistant Professor of Aerospace and Mechanical Engineering Umut Gurkan (co-PI) and Antonio De Luca, who was a visiting research scholar in Strangi's lab during this study and is now an associate professor of physics at the University of Calabria in Italy. The science The nanosensor, which fits in the palm of a hand, acts like a biological sieve, isolating a small protein molecule weighing less than 800 quadrillionths of a nanogram from an extremely dilute solution. To make the device so sensitive, Strangi's team faced two long-standing barriers: Light waves cannot detect objects smaller than their own physical dimensions, which range down to about half a micron. And molecules in dilute solutions float in Brownian motion and are unlikely to land on the sensor's surface. By harnessing nanotechnology tools and by coupling a microfluidic channel with an engineered material called a metamaterial, the scientist overcame the limits. The microfluidic channel restricts the molecules' ability to float around and drives them to the sensing area on the surface of the metamaterial. The metamaterial is made of a total of 16 nanostructured layers of reflective and conductive gold and transparent aluminum oxide, a dielectric, each 10s of atoms thick. Light directed onto and through the layers is concentrated into a very small volume much smaller than the wavelength of light. The top gold layer is perforated with holes, creating a grating that diffuses light shone on the surface into two dimensions. The incoming light, which is several hundreds of nanometers in wavelength, appears to be confined and concentrated in a few nanometers at the interface between the gold and the dielectric layer. As the light strikes the sensing area, it excites free electrons causing them to oscillate and generate a highly confined propagating surface wave, called a surface plasmon polariton. This propagating surface wave will in turn excite a bulk wave propagating across the sensing platform. The presence of the waves cause deep sharp dips in the spectrum of reflecting light. The combination and the interplay of surface plasmon and bulk plasmon waves are what make the sensor so sensitive. Strangi said. By exciting these waves through the eight bilayers of the metamaterial, they create remarkably sharp resonant modes. Extremely sharp and sensitive resonances can be used to detect smaller objects. "It's extremely sensitive," Strangi said. "When a small molecule lands on the surface, it results in a large local modification, causing the light to shift." The potential Depending on the size of the molecule, the reflecting light shifts different amounts. The researchers hope to learn to identify specific molecules, beginning with biomarkers for different cancers, by their light shifts. To add specificity to the sensor, the team added a layer of trap molecules, which are molecules that bind specifically with the molecules they hunt. In tests, the researchers used trap molecules to catch two different biomolecules: bovine serum albumin, with a molecular weight of 66,430 Daltons, and biotin, with a molecular weight of 244 Daltons. Each produced a signature light shift. Other researchers have reported using plasmon-based biosensors to detect biotin in solutions at concentrations ranging from more than 100 micromoles per liter to 10 micromoles per liter. This device proved 1 million times more sensitive, finding and identifying biotin at a concentration of 10 picomoles per liter. Testing and implications In Cleveland, Strangi and Nima Sharifi, MD, co-leader of the Genitourinary Cancer Program for the Case Comprehensive Cancer Center, have begun testing the sensor with proteins related to prostate cancers. "For some cancers, such as colorectal and pancreatic cancer, early detection is essential," said Sharifi, who is also the Kendrick Family Chair for Prostate Cancer Research at Cleveland Clinic. "High sensitivity detection of cancer-specific proteins in blood should enable detection of tumors when they are at an earlier disease stage. "This new sensing technology may help us not only detect cancers, but what subset of cancer, what's driving its growth and spread and what it's sensitive to," he said. "The sensor, for example, may help us determine markers of aggressive prostate cancers, which require treatments, or indolent forms that don't." Strangi's lab is working with other oncologists worldwide to test the device and begin moving the sensor toward clinical use. "We consider this just the beginning of our research," he said. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | March 28, 2016
Site: phys.org

Their goal: to provide oncologists a way to detect a single molecule of an enzyme produced by circulating cancer cells. Such detection could allow doctors to diagnose patients with certain cancers far earlier than possible today, monitor treatment and resistance and more. "The prognosis of many cancers depends on the stage of the cancer at diagnosis" said Giuseppe "Pino" Strangi, professor of physics at Case Western Reserve and leader of the research. "Very early, most circulating tumor cells express proteins of a very low molecular weight, less than 500 Daltons," Strangi explained. "These proteins are usually too small and in too low a concentration to detect with current test methods, yielding false negative results. "With this platform, we've detected proteins of 244 Daltons, which should enable doctors to detect cancers earlier—we don't know how much earlier yet," he said. "This biosensing platform may help to unlock the next era of initial cancer detection." The researchers believe the sensing technology will also be useful in diagnosing and monitoring other diseases as well. Their research is published online in the journal Nature Materials. It was a terrific teamwork, Strangi said. He worked with postdoctoral researchers Kandammathee Valiyaveedu Sreekanth and Efe Ilker, PhD students Yunus Alapan and Mohamed ElKabbash, Assistant Professor of Physics Michael Hinczewski, Assistant Professor of Aerospace and Mechanical Engineering Umut Gurkan (co-PI) and Antonio De Luca, who was a visiting research scholar in Strangi's lab during this study and is now an associate professor of physics at the University of Calabria in Italy. The nanosensor, which fits in the palm of a hand, acts like a biological sieve, isolating a small protein molecule weighing less than 800 quadrillionths of a nanogram from an extremely dilute solution. To make the device so sensitive, Strangi's team faced two long-standing barriers: Light waves cannot detect objects smaller than their own physical dimensions, which range down to about half a micron. And molecules in dilute solutions float in Brownian motion and are unlikely to land on the sensor's surface. By harnessing nanotechnology tools and by coupling a microfluidic channel with an engineered material called a metamaterial, the scientist overcame the limits. The microfluidic channel restricts the molecules' ability to float around and drives them to the sensing area on the surface of the metamaterial. The metamaterial is made of a total of 16 nanostructured layers of reflective and conductive gold and transparent aluminum oxide, a dielectric, each 10s of atoms thick. Light directed onto and through the layers is concentrated into a very small volume much smaller than the wavelength of light. The top gold layer is perforated with holes, creating a grating that diffuses light shone on the surface into two dimensions. The incoming light, which is several hundreds of nanometers in wavelength, appears to be confined and concentrated in a few nanometers at the interface between the gold and the dielectric layer. As the light strikes the sensing area, it excites free electrons causing them to oscillate and generate a highly confined propagating surface wave, called a surface plasmon polariton. This propagating surface wave will in turn excite a bulk wave propagating across the sensing platform. The presence of the waves cause deep sharp dips in the spectrum of reflecting light. The combination and the interplay of surface plasmon and bulk plasmon waves are what make the sensor so sensitive. Strangi said. By exciting these waves through the eight bilayers of the metamaterial, they create remarkably sharp resonant modes. Extremely sharp and sensitive resonances can be used to detect smaller objects. "It's extremely sensitive," Strangi said. "When a small molecule lands on the surface, it results in a large local modification, causing the light to shift." Depending on the size of the molecule, the reflecting light shifts different amounts. The researchers hope to learn to identify specific molecules, beginning with biomarkers for different cancers, by their light shifts. To add specificity to the sensor, the team added a layer of trap molecules, which are molecules that bind specifically with the molecules they hunt. In tests, the researchers used trap molecules to catch two different biomolecules: bovine serum albumin, with a molecular weight of 66,430 Daltons, and biotin, with a molecular weight of 244 Daltons. Each produced a signature light shift. Other researchers have reported using plasmon-based biosensors to detect biotin in solutions at concentrations ranging from more than 100 micromoles per liter to 10 micromoles per liter. This device proved 1 million times more sensitive, finding and identifying biotin at a concentration of 10 picomoles per liter. In Cleveland, Strangi and Nima Sharifi, MD, co-leader of the Genitourinary Cancer Program for the Case Comprehensive Cancer Center, have begun testing the sensor with proteins related to prostate cancers. "For some cancers, such as colorectal and pancreatic cancer, early detection is essential," said Sharifi, who is also the Kendrick Family Chair for Prostate Cancer Research at Cleveland Clinic. "High sensitivity detection of cancer-specific proteins in blood should enable detection of tumors when they are at an earlier disease stage. "This new sensing technology may help us not only detect cancers, but what subset of cancer, what's driving its growth and spread and what it's sensitive to," he said. "The sensor, for example, may help us determine markers of aggressive prostate cancers, which require treatments, or indolent forms that don't." Strangi's lab is working with other oncologists worldwide to test the device and begin moving the sensor toward clinical use. "We consider this just the beginning of our research," he said. Explore further: Virus detector harnesses ring of light in 'whispering gallery mode'


Winetrobe A.,University of Southern California | Dung M.,Aerospace and Mechanical Engineering | Jacobs M.,Aerospace and Mechanical Engineering
50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition | Year: 2012

The development of a smaller, cheaper, and more robust class of mobile robots is the next step toward the integration of robots into human environments. To address this challenge, a scaled prototype of a ballbot (a mobile robot actively balanced on a sphere) was designed and built to investigate its various design requirements and performance limitations. The current design includes a body mounted on the rubber inner-core of a volleyball, which is actuated in two axes. Wheels powered by two 34.7 W DC motors drive the ball in an inverse trackball configuration. Since the weight of the robot sits atop a sphere, the system acts as a dual-axis inverted-pendulum. An inertial measurement unit (IMU) provides measurements of the tilt of the body to a microcontroller, which then implements a control algorithm to determine the motor speed necessary to dynamically stabilize the robot. A motor controller conveys this input to the motors via pulse-width modulation. Testing was developed to (a) qualitatively display stability, (b) determine the experimental proportional power relationship necessary to recover from varying tilt, and (c) discern the limiting factors in the design. The testing succeeded in providing a proof of concept as the robot did remain stable for 4 2 s. Furthermore, quantitative testing at varying initial tilts determined a linear relationship between power and tilt angle. Limiting components of the design included drifting readings from the IMU, a simple control algorithm that prevented long-term stability, losses and inconsistencies in the drive train, and a minimum voltage output from the motor controller preventing control at small angles. These lessons learned in phase one of design and construction have helped to set future goals for the project including the integration of a filter(s) or an attitude and heading reference system (AHRS) to reduce error in tilt angle readings, the substitution of a more sensitive motor controller, and the optimization of the drive system to minimize losses; all of which would facilitate the development of a more sophisticated control algorithm and pave the way for the integration of actively-balanced robots into human environments. Copyright © 2012 by Victoria Bailey, Noe Cantu, Gary Garcia, Michael Orona. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.


Takahashi T.T.,Aerospace and Mechanical Engineering | Takahashi T.T.,Arizona State University | Lemonds T.,Aerospace and Mechanical Engineering | Lemonds T.,Arizona State University
15th AIAA Aviation Technology, Integration, and Operations Conference | Year: 2015

This paper describes the development of statistical semi-empirical relationships to help estimate the structural weight of wings, applicable to conventionally configured transport category aircraft design. These models are based upon a wing primary structure weight derived from an optimizing beam-element formulation. The underlying beam-element method sizes primary structure based upon “envelope” inertial and aerodynamic loads arising from maneuvering flight and hard-landing conditions. It sizes structure cognizant of tensile yield, compression yield, compression buckling of the skins and compression buckling limitations of integrally stiffened wing covers. Because our primary structural weights are based upon physical geometry we capture “real world” design effects that escape lower order physics based and purely empirical methods. Our trends differ substantially on many accounts from those “famous” wing weight regressions based upon simple strength concerns. © 2014 – T.T. Takahashi and T. Lemonds.


Yang S.L.,Aerospace and Mechanical Engineering | Spedding G.R.,Aerospace and Mechanical Engineering
43rd Fluid Dynamics Conference | Year: 2013

At transitional Reynolds numbers (104 - 105), many smooth airfoils experience laminar flow separation and possible turbulent reattachment, where the occurrence of either state is strongly in uenced by small changes in the surrounding environment. The Eppler 387 airfoil is one of many airfoils that can have multiple lift and drag states at a single wing incidence angle. Pre-stall hysteresis and abrupt switching between stable states occur due to sudden flow reattachment and the appearance of a separation bubble close to the leading edge. Here, we demonstrate control of the flow dynamics by localized acoustic excitation through small speakers embedded beneath the suction surface. The flow can be controlled not only through variations in acoustic power and frequency, but also through spatial variations in forcing location. Implications for control and stabilization of small aircraft are considered.

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