Shell-Isolated Tip-Enhanced Raman and Fluorescence Spectroscopy.

PubMed

Huang, Ya-Ping; Huang, Sheng-Chao; Wang, Xiang-Jie; Bodappa, Nataraju; Li, Chao-Yu; Yin, Hao; Su, Hai-Sheng; Meng, Meng; Zhang, Hua; Ren, Bin; Yang, Zhi-Lin; Zenobi, Renato; Tian, Zhong-Qun; Li, Jian-Feng

2018-06-18

Tip-enhanced Raman spectroscopy can provide molecular fingerprint information with ultrahigh spatial resolution, but the tip will be easily contaminated, thus leading to artifacts. It also remains a great challenge to establish tip-enhanced fluorescence because of the quenching resulting from the proximity of the metal tip. Herein, we report shell-isolated tip-enhanced Raman and fluorescence spectroscopies by employing ultrathin shell-isolated tips fabricated by atomic layer deposition. Such shell-isolated tips not only show outstanding electromagnetic field enhancement in TERS but also exclude interference by contaminants, thus greatly promoting applications in solution. Tip-enhanced fluorescence has also been achieved using these shell-isolated tips, with enhancement factors of up to 1.7×10 3 , consistent with theoretical simulations. Furthermore, tip-enhanced Raman and fluorescence signals are acquired simultaneously, and their relative intensities can be manipulated by changing the shell thickness. This work opens a new avenue for ultrahigh resolution surface analysis using plasmon-enhanced spectroscopies. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Report on using TIPS (Teaching Information Processing System) in teaching physics and astronomy

NASA Astrophysics Data System (ADS)

Folland, Nathan O.; Marchini, Robert R.; Rhyner, Charles R.; Zeilik, Michael

1983-05-01

A computer-managed instruction system, TIPS, has been used for over a decade in the teaching of diverse disciplines. This paper describes the recent use of TIPS in physics and astronomy courses at Kansas State University, Memphis State University, University of New Mexico, and University of Wisconsin-Green Bay. Student reactions to TIPS were largely positive, but the degree of success in improving student performance reported in many articles has not been observed.

Fit for Two: Tips for Pregnancy

MedlinePlus

... For Reporters Meetings & Workshops Follow Us Home Health Information Weight Management Health Tips for Pregnant Women Related Topics English ... at NIDDK Technology Advancement & Transfer Meetings & Workshops Health Information ... Disease Urologic Diseases Endocrine Diseases Diet & Nutrition ...

System and method for improved rotor tip performance

NASA Technical Reports Server (NTRS)

Zientek, Thomas A. (Inventor); Bussom, Richard (Inventor); McVeigh, Michael A. (Inventor); Narducci, Robert P. (Inventor)

2007-01-01

The present invention discloses systems and methods for the performance enhancement of rotary wing aircraft through reduced torque, noise and vibration. In one embodiment, a system includes a sail having an aerodynamic shape positioned proximate to a tip of the rotor blade. An actuator may be configured to rotate the sail relative to the blade tip. a A control system receives information from a rotorcraft system and commands the actuator to rotate the sail to a predetermined favorable rotor blade operating condition. In another embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail.

Smart helicopter rotor with active blade tips

NASA Astrophysics Data System (ADS)

Bernhard, Andreas Paul Friedrich

2000-10-01

control algorithm. Effective background vibration reduction of an intentional 1/rev hover imbalance was demonstrated. The control algorithm also showed the capability to generate desired multi-frequency control loads on the hub, based on artificial signal injection into the vibration measurement. The research program demonstrates the technical feasibility of the active blade tip concept for vibration reduction and warrants further investigation in terms of closed loop forward flight tests in the windtunnel and full scale design studies.

Employment and Training Legislation-1968; Background Information.

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. Senate Committee on Labor and Public Welfare.

This volume supplied background information for employment and training legislation for the Committee on Labor and Public Welfare of the United States Senate for 1968. It includes: (1) excerpts from reports and recommendations of national committees and commissions on civil disorders, rural poverty, technology and automation, food and fiber, and…

Remembering tips

MedlinePlus

Memory aids; Alzheimer disease - remembering tips; Early memory loss - remembering tips; Dementia - remembering tips ... harder for your brain to create a new memory, even while you can remember actions and events ...

Helping Your Child: Tips for Parents

MedlinePlus

... For Reporters Meetings & Workshops Follow Us Home Health Information Weight Management Helping Your Child: Tips for Parents Related Topics ... materials, visit https://www.niddk.nih.gov/health-information/weight-management . Clinical Trials The National Institute of Diabetes and ...

Flu Prevention and Treatment Tips

MedlinePlus

Flu Prevention and Treatment Tips Expert Information from Healthcare Professionals Who Specialize in the Care of Older Adults Influenza, or the “flu,” is a contagious respiratory illness. It can cause ...

Does Digital Ad Exposure Influence Information-Seeking Behavior Online? Evidence From the 2012 Tips From Former Smokers National Tobacco Prevention Campaign.

PubMed

Kim, Annice; Hansen, Heather; Duke, Jennifer; Davis, Kevin; Alexander, Robert; Rowland, Amy; Mitchko, Jane

2016-03-16

Measuring the impact of online health campaigns is challenging. Ad click-through rates are traditionally used to measure campaign reach, but few Internet users ever click on ads. Alternatively, self-reported exposure to digital ads would be prone to recall bias. Furthermore, there may be latency effects whereby people do not click on ads when exposed but visit the promoted website or conduct campaign-related searches later. Online panels that unobtrusively collect panelists' Web behavior data and link ad exposure to website visits and searches can more reliably assess the impact of digital ad exposure. From March to June 2012, the Centers for Disease Control and Prevention aired the national Tips From Former Smokers (Tips 2012) media campaign designed to encourage current smokers to quit. Advertisements ran across media channels, and the digital ads directed users to the Tips 2012 campaign website. Our aim was to examine whether exposure to Tips 2012 digital ads influenced information-seeking behaviors online. ComScore mined its panelists' Web behavior data for unique codes that would indicate exposure to Tips 2012 ads, regardless of whether panelists clicked the ad or not. A total of 15,319 US adults were identified as having been exposed to a Tips 2012 campaign ad. An equal number of unexposed adults (N=15,319) were identified and matched on demographics and Internet use behavior to the exposed group. Panelists' Web behavior data were mined for up to 4 weeks after initial Tips 2012 ad exposure to determine whether they visited the Tips 2012 campaign website or other cessation-related websites (eg, nicotine replacement therapy site) or conducted searches for campaign-related topics (eg, quit smoking). The proportion of exposed adults visiting the Tips 2012 sites increased from 0.4% in Week 1 to 0.9% 4 weeks after ad exposure, and these rates were significantly higher than in the unexposed group (0.1% in Week 1 to 0.4% in Week 4, P<.001) across all weeks examined

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit.

PubMed

Dixson, Ronald G; Orji, Ndubuisi G; Goldband, Ryan S

2016-01-25

Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM) probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 nm to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To validate that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD-tips, we recently performed experiments using a very large non-CD tip with an etched plateau of approximately 2 μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit

PubMed Central

Dixson, Ronald G.; Orji, Ndubuisi G.; Goldband, Ryan S.

2016-01-01

Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM) probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 nm to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To validate that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD-tips, we recently performed experiments using a very large non-CD tip with an etched plateau of approximately 2 μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm

The Institute of American Indian Arts Background Information (Task One of the Transition Evaluation). Background Paper.

ERIC Educational Resources Information Center

Tippeconnic, John W., Jr.

The paper, prepared as Task One of the Institute of American Indian Arts Transition Evaluation, provides pertinent background information about the Institute of American Indian Arts in Santa Fe, New Mexico. A brief history of the Institute is given, with information about its philosophy and purpose; objectives; organization and administration; the…

Evaluation of the tip-bending response in clinically used endoscopes

PubMed Central

Rozeboom, Esther D.; Reilink, Rob; Schwartz, Matthijs P.; Fockens, Paul; Broeders, Ivo A. M. J.

2016-01-01

Background and study aims: Endoscopic interventions require accurate and precise control of the endoscope tip. The endoscope tip response depends on a cable pulling system, which is known to deliver a significantly nonlinear response that eventually reduces control. It is unknown whether the current technique of endoscope tip control is adequate for a future of high precision procedures, steerable accessories, and add-on robotics. The aim of this study was to determine the status of the tip response of endoscopes used in clinical practice. Materials and methods: We evaluated 20 flexible colonoscopes and five gastroscopes, used in the endoscopy departments of a Dutch university hospital and two Dutch teaching hospitals, in a bench top setup. First, maximal tip bending was determined manually. Next, the endoscope navigation wheels were rotated individually in a motor setup. Tip angulation was recorded with a USB camera. Cable slackness was derived from the resulting hysteresis plot. Results: Only two of the 20 colonoscopes (10 %) and none of the five gastroscopes reached the maximal tip angulation specified by the manufacturer. Four colonoscopes (20 %) and none of the gastroscopes demonstrated the recommended cable tension. Eight colonoscopes (40 %) had undergone a maintenance check 1 month before the measurements were made. The tip responses of these eight colonoscopies did not differ significantly from the tip responses of the other colonoscopes. Conclusion: This study suggests that the majority of clinically used endoscopes are not optimally tuned to reach maximal bending angles and demonstrate adequate tip responses. We suggest a brief check before procedures to predict difficulties with bending angles and tip responses. PMID:27092330

Why background colour matters to bees and flowers.

PubMed

Bukovac, Zoë; Shrestha, Mani; Garcia, Jair E; Burd, Martin; Dorin, Alan; Dyer, Adrian G

2017-05-01

Flowers are often viewed by bee pollinators against a variety of different backgrounds. On the Australian continent, backgrounds are very diverse and include surface examples of all major geological stages of the Earth's history, which have been present during the entire evolutionary period of Angiosperms. Flower signals in Australia are also representative of typical worldwide evolutionary spectral adaptations that enable successful pollination. We measured the spectral properties of 581 natural surfaces, including rocks, sand, green leaves, and dry plant materials, sampled from tropical Cairns through to the southern tip of mainland Australia. We modelled in a hexagon colour space, how interactions between background spectra and flower-like colour stimuli affect reliable discrimination and detection in bee pollinators. We calculated the extent to which a given locus would be conflated with the loci of a different flower-colour stimulus using empirically determined colour discrimination regions for bee vision. Our results reveal that whilst colour signals are robust in homogeneous background viewing conditions, there could be significant pressure on plant flowers to evolve saliently-different colours to overcome background spectral noise. We thus show that perceptual noise has a large influence on how colour information can be used in natural conditions.

Study of mechanical behavior of AFM silicon tips under mechanical load

NASA Astrophysics Data System (ADS)

Kopycinska-Mueller, M.; Gluch, J.; Köhler, B.

2016-11-01

In this paper we address critical issues concerning calibration of AFM based methods used for nanoscale mechanical characterization of materials. It has been shown that calibration approaches based on macroscopic models for contact mechanics may yield excellent results in terms of the indentation modulus of the sample, but fail to provide a comprehensive and actual information concerning the tip-sample contact radius or the mechanical properties of the tip. Explanations for the severely reduced indentation modulus of the tip included the inadequacies of the models used for calculations of the tip-sample contact stiffness, discrepancies in the actual and ideal shape of the tip, presence of the amorphous silicon phase within the silicon tip, as well as negligence of the actual size of the stress field created in the tip during elastic interactions. To clarify these issues, we investigated the influence of the mechanical load applied to four AFM silicon tips on their crystalline state by exposing them to systematically increasing loads, evaluating the character of the tip-sample interactions via the load-unload stiffness curves, and assessing the state of the tips from HR-TEM images. The results presented in this paper were obtained in a series of relatively simple and basic atomic force acoustic microscopy (AFAM) experiments. The novel combination of TEM imaging of the AFM tips with the analysis of the load-unload stiffness curves gave us a detailed insight into their mechanical behavior under load conditions. We were able to identify the limits for the elastic interactions, as well as the hallmarks for phase transformation and dislocation formation and movement. The comparison of the physical dimensions of the AFM tips, geometry parameters determined from the values of the contact stiffness, and the information on the crystalline state of the tips allowed us a better understanding of the nanoscale contact.

PhenoTips: patient phenotyping software for clinical and research use.

PubMed

Girdea, Marta; Dumitriu, Sergiu; Fiume, Marc; Bowdin, Sarah; Boycott, Kym M; Chénier, Sébastien; Chitayat, David; Faghfoury, Hanna; Meyn, M Stephen; Ray, Peter N; So, Joyce; Stavropoulos, Dimitri J; Brudno, Michael

2013-08-01

We have developed PhenoTips: open source software for collecting and analyzing phenotypic information for patients with genetic disorders. Our software combines an easy-to-use interface, compatible with any device that runs a Web browser, with a standardized database back end. The PhenoTips' user interface closely mirrors clinician workflows so as to facilitate the recording of observations made during the patient encounter. Collected data include demographics, medical history, family history, physical and laboratory measurements, physical findings, and additional notes. Phenotypic information is represented using the Human Phenotype Ontology; however, the complexity of the ontology is hidden behind a user interface, which combines simple selection of common phenotypes with error-tolerant, predictive search of the entire ontology. PhenoTips supports accurate diagnosis by analyzing the entered data, then suggesting additional clinical investigations and providing Online Mendelian Inheritance in Man (OMIM) links to likely disorders. By collecting, classifying, and analyzing phenotypic information during the patient encounter, PhenoTips allows for streamlining of clinic workflow, efficient data entry, improved diagnosis, standardization of collected patient phenotypes, and sharing of anonymized patient phenotype data for the study of rare disorders. Our source code and a demo version of PhenoTips are available at http://phenotips.org. © 2013 WILEY PERIODICALS, INC.

On the Tip-of-the-Tongue.

ERIC Educational Resources Information Center

Moses, Barbara

1988-01-01

Discusses the organization and retrieval of information. Describes the tip-of-the-tongue state during mathematics problem solving. Provides five rules for a deep level of processing of new concepts. (YP)

Influence of blade tip rounding on tip leakage vortex cavitation of axial flow pump

NASA Astrophysics Data System (ADS)

Wu, S. Q.; Shi, W. D.; Zhang, D. S.; Yao, J.; Cheng, C.

2013-12-01

Tip leakage flow in axial flow pumps is mainly caused by the tip clearance, which is the main cause of tip leakage vortex cavitation and blade tip cavitation erosion. In order to improve tip clearance flow and reduce TLV cavitation, four schemes were adopted to the round blade tip. These are: no tip rounding, one time tip clearance tip rounding, two times tip clearance tip rounding, four times tip clearance tip rounding. Using SST k-ω turbulence model and Zwart cavitation model in CFX software, this simulation obtained four kinds of inner flow field results. The numerical results indicated that with the increase of r*, NPSHc gradually increased and the cavitation performance reduced. However, corner vortex was eliminated so that cavitation in gap was restrained. But TLV vorticity increased and cavitation's range here had a little expansion. Combined with the research of this paper and the different analyses of four schemes, we recommend adopting the two times of the tip clearance rounding.

Theoretical Study of tip apex electronic structure in Scanning Tunneling Microscope

NASA Astrophysics Data System (ADS)

Choi, Heesung; Huang, Min; Randall, John; Cho, Kyeongjae

2011-03-01

Scanning Tunneling Microscope (STM) has been widely used to explore diverse surface properties with an atomic resolution, and STM tip has played a critical role in controlling surface structures. However, detailed information of atomic and electronic structure of STM tip and the fundamental understanding of STM images are still incomplete. Therefore, it is important to develop a comprehensive understanding of the electronic structure of STM tip. We have studied the atomic and electronic structures of STM tip with various transition metals (TMs) by DFT method. The d-electrons of TM tip apex atoms show different orbital states near the Fermi level. We will present comprehensive data of STM tips from our DFT calculation. Verified quantification of the tip electronic structures will lead to fundamental understanding of STM tip structure-property relationship. This work is supported by the DARPA TBN Program and the Texas ETF. DARPA Tip Based Nanofabrication Program and the Emerging Technology Fund of the State of Texas.

29 CFR Appendix A to §§ 1605.2 and... - Background Information

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 4 2010-07-01 2010-07-01 false Background Information A Appendix A to §§ 1605.2 and 1605... §§ 1605.2 and 1605.3—Background Information In 1966, the Commission adopted guidelines on religious... of Trans World Airlines' business, and would therefore, exceed the duty to accommodate Hardison. In...

29 CFR Appendix A to §§ 1605.2 and... - Background Information

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 4 2011-07-01 2011-07-01 false Background Information A Appendix A to §§ 1605.2 and 1605... §§ 1605.2 and 1605.3—Background Information In 1966, the Commission adopted guidelines on religious... of Trans World Airlines' business, and would therefore, exceed the duty to accommodate Hardison. In...

Comparison of Various Supersonic Turbine Tip Designs to Minimize Aerodynamic Loss and Tip Heating

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Ameri, Ali

2012-01-01

The rotor tips of axial turbines experience high heat flux and are the cause of aerodynamic losses due to tip clearance flows, and in the case of supersonic tips, shocks. As stage loadings increase, the flow in the tip gap approaches and exceeds sonic conditions. This introduces effects such as shock-boundary layer interactions and choked flow that are not observed for subsonic tip flows that have been studied extensively in literature. This work simulates the tip clearance flow for a flat tip, a diverging tip gap and several contoured tips to assess the possibility of minimizing tip heat flux while maintaining a constant massflow from the pressure side to the suction side of the rotor, through the tip clearance. The Computational Fluid Dynamics (CFD) code GlennHT was used for the simulations. Due to the strong favorable pressure gradients the simulations assumed laminar conditions in the tip gap. The nominal tip gap width to height ratio for this study is 6.0. The Reynolds number of the flow is 2.4 x 10(exp 5) based on nominal tip width and exit velocity. A wavy wall design was found to reduce heat flux by 5 percent but suffered from an additional 6 percent in aerodynamic loss coefficient. Conventional tip recesses are found to perform far worse than a flat tip due to severe shock heating. Overall, the baseline flat tip was the second best performer. A diverging converging tip gap with a hole was found to be the best choice. Average tip heat flux was reduced by 37 percent and aerodynamic losses were cut by over 6 percent.

Technical tips for collagenase injection treatment for Dupuytren contracture.

PubMed

Meals, Roy A; Hentz, Vincent R

2014-06-01

We describe technical tips for injecting collagenase into Dupuytren cords based on experience acquired during the prerelease Food and Drug Administration clinical trials and with subsequent clinical practice. These tips include techniques for extracting the reconstituted enzyme efficiently from the vial, injecting the cord(s) with increased safety to the tendons, and anesthetizing the hand before manipulation. The tips are intended to supplement but by no means replace the manufacturer's prescribing information and training video. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Probe tip heating assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmitz, Roger William; Oh, Yunje

A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably receivedmore » and clamped within the socket.« less

Effect of tip flange on tip leakage flow of small axial flow fans

NASA Astrophysics Data System (ADS)

Zhang, Li; Jin, Yingzi; Jin, Yuzhen

2014-02-01

Aerodynamic performance of an axial flow fan is closely related to its tip clearance leakage flow. In this paper, the hot-wire anemometer is used to measure the three dimensional mean velocity near the blade tips. Moreover, the filtered N-S equations with finite volume method and RNG k-ɛ turbulence model are adopted to carry out the steady simulation calculation of several fans that differ only in tip flange shape and number. The large eddy simulation and the FW-H noise models are adopted to carry out the unsteady numerical calculation and aerodynamic noise prediction. The results of simulation calculation agree roughly with that of tests, which proves the numerical calculation method is feasible.The effects of tip flange shapes and numbers on the blade tip vortex structure and the characteristics are analyzed. The results show that tip flange of the fan has a certain influence on the characteristics of the fan. The maximum efficiencies for the fans with tip flanges are shifted towards partial flow with respect to the design point of the datum fan. Furthermore, the noise characteristics for the fans with tip flanges have become more deteriorated than that for the datum fan. Tip flange contributes to forming tip vortex shedding and the effect of the half-cylinder tip flange on tip vortex shedding is obvious. There is a distinct relationship between the characteristics of the fan and tip vortex shedding. The research results provide the profitable reference for the internal flow mechanism of the performance optimization of small axial flow fans.

Five Tips to Help Prevent Infections

MedlinePlus

... Information For… Media Policy Makers 5 Tips to Help Prevent Infections Language: English (US) Español (Spanish) Recommend ... Makers Language: English (US) Español (Spanish) File Formats Help: How do I view different file formats (PDF, ...

Retrieval of the 1964 Laser Literature Using MIT's Project Tip.

ERIC Educational Resources Information Center

Keenan, Stella; Terry, Edward

Reported are the performance characteristics of the Massachusetts Institute of Technology Technical Information Program (TIP) system based on a study involving three search strategies in retrieval o f laser articles published in 1964. The TIP system provides access to (1) title, (2) author(s), (3) bibliographic references, and (4) literature…

HotTips for Teachers: 30 Steps to Student Engagement.

ERIC Educational Resources Information Center

Abernathy, Rob; Reardon, Mark

This book shows teachers how to reclaim their students' attention and, in the process, help them absorb information and stay on task. There are over 30 tips that are practical, not always obvious, and well tested. Three parts focus on: (1) "HotTips for Opening the Lesson" (e.g., fill the room with I.D. posters, ask opening questions, get…

Tip-enhanced Raman mapping with top-illumination AFM.

PubMed

Chan, K L Andrew; Kazarian, Sergei G

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Arctic climate tipping points.

PubMed

Lenton, Timothy M

2012-02-01

There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the Arctic are briefly reviewed. Then, the current behaviour of a range of Arctic systems is summarised. Looking ahead, a range of potential tipping phenomena are described. This leads to a revised and expanded list of potential Arctic climate tipping elements, whose likelihood is assessed, in terms of how much warming will be required to tip them. Finally, the available responses are considered, especially the prospects for avoiding Arctic climate tipping points.

[Over projected tip].

PubMed

Duron, J-B; Nguyen, P S; Levet, Y; Bardot, J; Aiach, G

2014-12-01

Overprojected tip is a pretty usual request not easy to manage. Preop analysis is crucial in order to evaluate tip support and skin thickness and ability to retract. For example, if the skin is very thick and has poor chance to retract, the surgeon should be very careful in the tip projection decreasing to avoid a skin pollybeak deformity. In such cases, he has to analyze the facial proportions, especially other areas projection (radix, dorsum and chin) and think about augmenting them to balance the profile rather than decreasing tip projection. Correction should always be conducted incrementally, starting with weakening the tip support mechanisms and, only if necessary, continue with alar cartilage interruption. This can be performed on many areas (lateral cruras, domes, medial cruras) and with several techniques (resection or interruption+overlapping). Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping.

PubMed

Clifton, Sara M; Herbers, Eileen; Chen, Jack; Abrams, Daniel M

2018-02-01

The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.

The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping

NASA Astrophysics Data System (ADS)

Clifton, Sara M.; Herbers, Eileen; Chen, Jack; Abrams, Daniel M.

2018-02-01

The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.

Synthetic fiber production facilities: Background information for proposed standards

NASA Astrophysics Data System (ADS)

Goodwin, D. R.

1982-10-01

Standards of performance to control emissions of volatile organic compounds (VOC) from new, modified, and reconstructed synthetic fiber production facilities are being proposed under section III of the Clean Air Act. This document contains information on the background and authority, regulatory alternatives considered, and environmental and economic impacts of the regulatory alternatives.

Separation of foreground and background from light field using gradient information.

PubMed

Lee, Jae Young; Park, Rae-Hong

2017-02-01

Studies of computer vision or machine vision applications using a light field camera have been increasing in recent years. However, the abilities that the light field camera has are not fully used in these applications. In this paper, we propose a method for direct separation of foreground and background that uses the gradient information and can be used in various applications such as pre-processing. From an optical phenomenon whereby the bundles of rays from the background are flipped, we derive that the disparity sign of the background in the captured three-dimensional scene has the opposite disparity sign of the foreground. Using the majority-weighted voting algorithm based on the gradient information with the Lambertian assumption and the gradient constraint, the foreground and background can be separated at each pixel. In regard to pre-processing, the proposed method can be used for various applications such as occlusion and saliency detection, disparity estimation, and so on. Experimental results with the EPFL light field dataset and Stanford Lytro light field dataset show that the proposed method achieves better performance in terms of the occlusion detection, and thus can be effectively used in pre-processing for saliency detection and disparity estimation.

The Effects of Background Information on Standarized Test Scores.

ERIC Educational Resources Information Center

Feeley, Joan T.; Wepner, Shelley B.

A study was conducted to determine the effects of exposure to the topics included on the comprehension subtest of the Nelson-Denny Reading Test (ND), Form F, on college freshmen's performance on the test. In addition, the study investigated whether those students with background information would indicate their awareness of this knowledge on a…

Experimental Study of Unshrouded Impeller Pump Stage Sensitivity to Tip Clearance

NASA Technical Reports Server (NTRS)

Williams, Robert W.; Zoladz, Thomas; Storey, Anne K.; Skelley, Stephen E.

2002-01-01

This viewgraph presentation provides information on an experiment. Its objective is to experimentally determine unshrouded impeller performance sensitivity to tip clearance. The experiment included: Determining impeller efficiency at scaled operating conditions in water at MSFC's Pump Test Equipment (PTE) Facility; Testing unshrouded impeller at three different tip clearances; Testing each tip clearance configuration at on- and off-design conditions, and collecting unsteady- and steady-state data in each configuration; Determining impeller efficiency directly using drive line torquemeter and pump inlet and exit total pressure measurements.

Technology Tips

ERIC Educational Resources Information Center

Mathematics Teacher, 2004

2004-01-01

Some inexpensive or free ways that enable to capture and use images in work are mentioned. The first tip demonstrates the methods of using some of the built-in capabilities of the Macintosh and Windows-based PC operating systems, and the second tip describes methods to capture and create images using SnagIt.

Ten Tips for Better Time Management.

ERIC Educational Resources Information Center

Van Loozen, Luann F.

1982-01-01

Presents time management tips, especially for board of education members, including recommendations to realize that managing time is a skill, develop a more accurate sense of how one's time is spent, examine and reestablish goals, learn to say no, organize files and information, and master the telephone. (Author/JM)

Modeling and estimation of tip contact force for steerable ablation catheters.

PubMed

Khoshnam, Mahta; Skanes, Allan C; Patel, Rajni V

2015-05-01

The efficacy of catheter-based cardiac ablation procedures can be significantly improved if real-time information is available concerning contact forces between the catheter tip and cardiac tissue. However, the widely used ablation catheters are not equipped for force sensing. This paper proposes a technique for estimating the contact forces without direct force measurements by studying the changes in the shape of the deflectable distal section of a conventional 7-Fr catheter (henceforth called the "deflectable distal shaft," the "deflectable shaft," or the "shaft" of the catheter) in different loading situations. First, the shaft curvature when the tip is moving in free space is studied and based on that, a kinematic model for the deflectable shaft in free space is proposed. In the next step, the shaft shape is analyzed in the case where the tip is in contact with the environment, and it is shown that the curvature of the deflectable shaft provides useful information about the loading status of the catheter and can be used to define an index for determining the range of contact forces exerted by the ablation tip. Experiments with two different steerable ablation catheters show that the defined index can detect the range of applied contact forces correctly in more than 80% of the cases. Based on the proposed technique, a framework for obtaining contact force information by using the shaft curvature at a limited number of points along the deflectable shaft is constructed. The proposed kinematic model and the force estimation technique can be implemented together to describe the catheter's behavior before contact, detect tip/tissue contact, and determine the range of contact forces. This study proves that the flexibility of the catheter's distal shaft provides a means of estimating the force exerted on tissue by the ablation tip.

Tip-enhanced Raman scattering microscopy: Recent advance in tip production

NASA Astrophysics Data System (ADS)

Fujita, Yasuhiko; Walke, Peter; De Feyter, Steven; Uji-i, Hiroshi

2016-08-01

Tip-enhanced Raman scattering (TERS) microscopy is a technique that combines the chemical sensitivity of Raman spectroscopy with the resolving power of scanning probe microscopy. The key component of any TERS setup is a plasmonically-active noble metal tip, which serves to couple far-field incident radiation with the near-field. Thus, the design and implementation of reproducible probes are crucial for the continued development of TERS as a tool for nanoscopic analysis. Here we discuss conventional methods for the fabrication of TERS-ready tips, highlighting the problems therein, as well as detailing more recent developments to improve reducibility. In addition, the idea of remote excitation-TERS is enlightened upon, whereby TERS sensitivity is further improved by using propagating surface plasmons to separate the incident radiation from the tip apex, as well as how this can be incorporated into the fabrication process.

Improving Your Health: Tips for African American Men and Women

MedlinePlus

... For Reporters Meetings & Workshops Follow Us Home Health Information Weight Management Health Tips for African-Americans Related Topics Section ... at NIDDK Technology Advancement & Transfer Meetings & Workshops Health Information ... Disease Urologic Diseases Endocrine Diseases Diet & Nutrition ...

Turbine blade tip clearance measurement using a skewed dual-beam fiber optic sensor

NASA Astrophysics Data System (ADS)

Ye, De-chao; Duan, Fa-jie; Guo, Hao-tian; Li, Yangzong; Wang, Kai

2012-08-01

Optimization and active control of the tip clearance of turbine blades has been identified as a key to improve fuel efficiency, reduce emission, and increase service life of the engine. However, reliable and real-time tip clearance measurement is difficult due to the adverse environmental conditions that are typically found in a turbine. We describe a dual-beam fiber optic measurement system that can measure the tip timing and tip clearance simultaneously. Because the tip timing information is used to calculate the tip clearance, the method is insensitive to the signal intensity variation caused by fluctuations in environmental conditions such as light source instability, contamination, and blade tip imperfection. The system was calibrated and tested using experimental rotors. The test results indicated a high resolution of 4.5 μm and measurement accuracy of ±20 μm over the rotation speed range of 2000 to 10,000 rpm.

Cellular functions of TIP60.

PubMed

Sapountzi, Vasileia; Logan, Ian R; Robson, Craig N

2006-01-01

TIP60 was originally identified as a cellular acetyltransferase protein that interacts with HIV-1 Tat. As a consequence, the role of TIP60 in transcriptional regulation has been investigated intensively. Recent data suggest that TIP60 has more divergent functions than originally thought and roles for TIP60 in many processes, such as cellular signalling, DNA damage repair, cell cycle and checkpoint control and apoptosis are emerging. TIP60 is a tightly regulated transcriptional coregulator, acting in a large multiprotein complex for a range of transcription factors including androgen receptor, Myc, STAT3, NF-kappaB, E2F1 and p53. This usually involves recruitment of TIP60 acetyltransferase activities to chromatin. Additionally, in response to DNA double strand breaks, TIP60 is recruited to DNA lesions where it participates both in the initial as well as the final stages of repair. Here, we describe how TIP60 is a multifunctional enzyme involved in multiple nuclear transactions.

76 FR 69287 - National Instant Criminal Background Check System Section Agency Information Collection...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-08

... System Section Agency Information Collection Activities: Existing collection, comments requested the Voluntary Appeal File (VAF) Brochure ACTION: 60-Day Notice of Information Collection Under Review. The... Criminal Background Check System (NICS) Section has submitted the following information collection request...

Nano-Wilhelmy investigation of dynamic wetting properties of AFM tips through tip-nanobubble interaction

PubMed Central

Wang, Yuliang; Wang, Huimin; Bi, Shusheng; Guo, Bin

2016-01-01

The dynamic wetting properties of atomic force microscopy (AFM) tips are of much concern in many AFM-related measurement, fabrication, and manipulation applications. In this study, the wetting properties of silicon and silicon nitride AFM tips are investigated through dynamic contact angle measurement using a nano-Wilhelmy balance based method. This is done by capillary force measurement during extension and retraction motion of AFM tips relative to interfacial nanobubbles. The working principle of the proposed method and mathematic models for dynamic contact angle measurement are presented. Geometric models of AFM tips were constructed using scanning electronic microscopy (SEM) images taken from different view directions. The detailed process of tip-nanobubble interaction was investigated using force-distance curves of AFM on nanobubbles. Several parameters including nanobubble height, adhesion and capillary force between tip and nanobubbles are extracted. The variation of these parameters was studied over nanobubble surfaces. The dynamic contact angles of the AFM tips were calculated from the capillary force measurements. The proposed method provides direct measurement of dynamic contact angles for AFM tips and can also be taken as a general approach for nanoscale dynamic wetting property investigation. PMID:27452115

Nano-Wilhelmy investigation of dynamic wetting properties of AFM tips through tip-nanobubble interaction

NASA Astrophysics Data System (ADS)

Wang, Yuliang; Wang, Huimin; Bi, Shusheng; Guo, Bin

2016-07-01

The dynamic wetting properties of atomic force microscopy (AFM) tips are of much concern in many AFM-related measurement, fabrication, and manipulation applications. In this study, the wetting properties of silicon and silicon nitride AFM tips are investigated through dynamic contact angle measurement using a nano-Wilhelmy balance based method. This is done by capillary force measurement during extension and retraction motion of AFM tips relative to interfacial nanobubbles. The working principle of the proposed method and mathematic models for dynamic contact angle measurement are presented. Geometric models of AFM tips were constructed using scanning electronic microscopy (SEM) images taken from different view directions. The detailed process of tip-nanobubble interaction was investigated using force-distance curves of AFM on nanobubbles. Several parameters including nanobubble height, adhesion and capillary force between tip and nanobubbles are extracted. The variation of these parameters was studied over nanobubble surfaces. The dynamic contact angles of the AFM tips were calculated from the capillary force measurements. The proposed method provides direct measurement of dynamic contact angles for AFM tips and can also be taken as a general approach for nanoscale dynamic wetting property investigation.

The information content of cosmic microwave background anisotropies

NASA Astrophysics Data System (ADS)

Scott, Douglas; Contreras, Dagoberto; Narimani, Ali; Ma, Yin-Zhe

2016-06-01

The cosmic microwave background (CMB) contains perturbations that are close to Gaussian and isotropic. This means that its information content, in the sense of the ability to constrain cosmological models, is closely related to the number of modes probed in CMB power spectra. Rather than making forecasts for specific experimental setups, here we take a more pedagogical approach and ask how much information we can extract from the CMB if we are only limited by sample variance. We show that, compared with temperature measurements, the addition of E-mode polarization doubles the number of modes available out to a fixed maximum multipole, provided that all of the TT, TE, and EE power spectra are measured. However, the situation in terms of constraints on particular parameters is more complicated, as we explain and illustrate graphically. We also discuss the enhancements in information that can come from adding B-mode polarization and gravitational lensing. We show how well one could ever determine the basic cosmological parameters from CMB data compared with what has been achieved with Planck, which has already probed a substantial fraction of the TT information. Lastly, we look at constraints on neutrino mass as a specific example of how lensing information improves future prospects beyond the current 6-parameter model.

Dissatisfaction with Nasal Tip Shape: Secondary Tip Maneuvers.

PubMed

Moyer, Jeffrey S

2018-06-01

Dissatisfaction with the appearance of the nasal tip is a common compliant in patients seeking revision surgery after rhinoplasty. Revision rhinoplasty is more technically difficult and unpredictable given the frequent presence of scar contracture, impaired skin envelope quality, and missing alar cartilage. This article describes some of the more common causes for tip revision surgery and techniques to address these abnormalities. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Choice of tip, signal stability, and practical aspects of piezoresponse-force-microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henrichs, L. F.; Bennett, J.; Bell, A. J.

2015-08-15

Piezoresponse force-microscopy (PFM) has become the standard tool to investigate ferroelectrics on the micro- and nanoscale. However, reliability of PFM signals is often problematic and their quantification is challenging and thus not widely applied. Here, we present a study of the reproducibility of PFM signals and of the so-called PFM background signal which has been reported in the literature. We find that PFM signals are generally reproducible to certain extents. The PFM signal difference between 180° domains on periodically poled lithium niobate (PPLN) is taken as the reference signal in a large number of measurements, carried out in a lowmore » frequency regime (30-70 kHz). We show that in comparison to Pt coated tips, diamond coated tips exhibit improved signal stability, lower background signal, and less imaging artifacts related to PFM which is reflected in the spread of measurements. This is attributed to the improved mechanical stability of the conductive layer. The average deviation of the mean PFM signal is 38.3%, for a diamond coated tip. Although this deviation is relatively high, it is far better than values from the literature which showed a deviation of approx. 73.1%. Additionally, we find that the average deviation of the background signal from 0 is 11.6% of the PPLN domain contrast. Thus, the background signal needs to be taken into account when quantifying PFM signals and should be subtracted from PFM signals. Those results are important for quantification of PFM signals, since PPLN might be used for this purpose when PFM signals measured on PPLN are related to its macroscopic d{sub 33} coefficient. Finally, the crucial influence of sample polishing on PFM signals is shown and we recommend to use a multistep polishing route with a final step involving 200 nm sized colloidal silica particles.« less

Time To Talk with Your Health Care Providers: 4 Tips to Start the Conversation

MedlinePlus

... Y Z 4 Tips: Start Talking With Your Health Care Providers About Complementary Health Approaches Share: When patients ... fully informed and can help patients make wise health care decisions. Here are 4 tips to help you ...

CANNONS BESIDE MEMORIAL WALK, WITH RODMAN MONUMENT AT LEFT BACKGROUND. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CANNONS BESIDE MEMORIAL WALK, WITH RODMAN MONUMENT AT LEFT BACKGROUND. VIEW TO NORTHWEST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

CargoTIPS: an innovative approach to combating cargo theft

NASA Astrophysics Data System (ADS)

Toth, Gail E.

1998-12-01

Cargo theft has been estimated by the Federal Bureau o Investigations to be 6 billion annually, while others believe it to be more than 10 billion annually. Opportunistic thieves, street gangs, traditional organized crime groups, and new organized crime groups have been targeting cargo. They steal from warehouses, terminals, equipment, truck stops, or any place where freight comes to a rest. With zero inventory levels, our trailers have become virtual warehouses on wheels and easy targets for thieves. Without information and communication cargo thieves can thrive. The industry and law enforcement are forced into being reactive instead of developing proactive policies and procedures. Cargo thieves cross town lines, county lines, state lines and country borders. This makes communication within the law enforcement community imperative. CargoTIPS (cargo theft information processing system) was developed in response to the need for cargo theft information. The system allows us to collect cargo theft statistics to analyze the problem, assess the threat and develop a response on a national level. CargoTIPS includes a bulletin board, which allows users to communicate with each other, pass on alerts or seek information. The system is also used as an investigative tool. CargoTIPS can identify the mode of transportation (truck, small parcel, air, rail or ocean). It was designed to take in international data. Currently the system has identified that food products are the number one targeted commodity, followed by electronic products and third, computers and computer parts.

Students Seeking Access to Four-Year Institutions: Community College Transfers [Background Information].

ERIC Educational Resources Information Center

Moore, Jamillah

This publication provides background information for a hearing by the California Senate Select Committee on Higher Education and Outreach on December 3, 1997. The Introduction presents the Committee announcement, press release, agenda, information about transfer efforts in California, facts and figures about the community colleges, and the text of…

Child Transportation Safety Tips.

ERIC Educational Resources Information Center

National Highway Traffic Safety Administration (DOT), Washington, DC.

This document presents nine tips regarding safe infant and child transportation, each tip explained in one to two pages. The tips are as follows: (1) quick safety seat checkup; (2) where should your child ride? (3) how to protect your new baby in the car; (4) what safety seat to use for a big baby or toddler? (5) how should preschool and school…

Method to improve the blade tip-timing accuracy of fiber bundle sensor under varying tip clearance

NASA Astrophysics Data System (ADS)

Duan, Fajie; Zhang, Jilong; Jiang, Jiajia; Guo, Haotian; Ye, Dechao

2016-01-01

Blade vibration measurement based on the blade tip-timing method has become an industry-standard procedure. Fiber bundle sensors are widely used for tip-timing measurement. However, the variation of clearance between the sensor and the blade will bring a tip-timing error to fiber bundle sensors due to the change in signal amplitude. This article presents methods based on software and hardware to reduce the error caused by the tip clearance change. The software method utilizes both the rising and falling edges of the tip-timing signal to determine the blade arrival time, and a calibration process suitable for asymmetric tip-timing signals is presented. The hardware method uses an automatic gain control circuit to stabilize the signal amplitude. Experiments are conducted and the results prove that both methods can effectively reduce the impact of tip clearance variation on the blade tip-timing and improve the accuracy of measurements.

System and method for improved rotor tip performance

NASA Technical Reports Server (NTRS)

Bussom, Richard (Inventor); McVeigh, Michael A. (Inventor); Narducci, Robert P. (Inventor); Zientek, Thomas A. (Inventor)

2010-01-01

Embodiments of systems and methods for enhancing the performance of rotary wing aircraft through reduced torque, noise and vibration are disclosed. In one embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail. Alternately, input signals may be communicated to a control system operable to position a plurality of sails, each sail having an aerodynamic shape and positioned proximate to a tip portion of the rotor blade. The input signals may be configured to rotate each sail about a longitudinal axis into a corresponding pitch angle independently of the other sails.

The information content of cosmic microwave background anisotropies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Douglas; Contreras, Dagoberto; Narimani, Ali

The cosmic microwave background (CMB) contains perturbations that are close to Gaussian and isotropic. This means that its information content, in the sense of the ability to constrain cosmological models, is closely related to the number of modes probed in CMB power spectra. Rather than making forecasts for specific experimental setups, here we take a more pedagogical approach and ask how much information we can extract from the CMB if we are only limited by sample variance. We show that, compared with temperature measurements, the addition of E -mode polarization doubles the number of modes available out to a fixedmore » maximum multipole, provided that all of the TT , TE , and EE power spectra are measured. However, the situation in terms of constraints on particular parameters is more complicated, as we explain and illustrate graphically. We also discuss the enhancements in information that can come from adding B -mode polarization and gravitational lensing. We show how well one could ever determine the basic cosmological parameters from CMB data compared with what has been achieved with Planck , which has already probed a substantial fraction of the TT information. Lastly, we look at constraints on neutrino mass as a specific example of how lensing information improves future prospects beyond the current 6-parameter model.« less

Dielectrophoretic positioning of single nanoparticles on atomic force microscope tips for tip-enhanced Raman spectroscopy.

PubMed

Leiterer, Christian; Deckert-Gaudig, Tanja; Singh, Prabha; Wirth, Janina; Deckert, Volker; Fritzsche, Wolfgang

2015-05-01

Tip-enhanced Raman spectroscopy, a combination of Raman spectroscopy and scanning probe microscopy, is a powerful technique to detect the vibrational fingerprint of molecules at the nanometer scale. A metal nanoparticle at the apex of an atomic force microscope tip leads to a large enhancement of the electromagnetic field when illuminated with an appropriate wavelength, resulting in an increased Raman signal. A controlled positioning of individual nanoparticles at the tip would improve the reproducibility of the probes and is quite demanding due to usually serial and labor-intensive approaches. In contrast to commonly used submicron manipulation techniques, dielectrophoresis allows a parallel and scalable production, and provides a novel approach toward reproducible and at the same time affordable tip-enhanced Raman spectroscopy tips. We demonstrate the successful positioning of an individual plasmonic nanoparticle on a commercial atomic force microscope tip by dielectrophoresis followed by experimental proof of the Raman signal enhancing capabilities of such tips. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Information gains from cosmic microwave background experiments

NASA Astrophysics Data System (ADS)

Seehars, Sebastian; Amara, Adam; Refregier, Alexandre; Paranjape, Aseem; Akeret, Joël

2014-07-01

To shed light on the fundamental problems posed by dark energy and dark matter, a large number of experiments have been performed and combined to constrain cosmological models. We propose a novel way of quantifying the information gained by updates on the parameter constraints from a series of experiments which can either complement earlier measurements or replace them. For this purpose, we use the Kullback-Leibler divergence or relative entropy from information theory to measure differences in the posterior distributions in model parameter space from a pair of experiments. We apply this formalism to a historical series of cosmic microwave background experiments ranging from Boomerang to WMAP, SPT, and Planck. Considering different combinations of these experiments, we thus estimate the information gain in units of bits and distinguish contributions from the reduction of statistical errors and the "surprise" corresponding to a significant shift of the parameters' central values. For this experiment series, we find individual relative entropy gains ranging from about 1 to 30 bits. In some cases, e.g. when comparing WMAP and Planck results, we find that the gains are dominated by the surprise rather than by improvements in statistical precision. We discuss how this technique provides a useful tool for both quantifying the constraining power of data from cosmological probes and detecting the tensions between experiments.

Prom Health and Safety Tips

MedlinePlus

... Halloween Prom Tips Spring Break Valentine Tips Winter Holiday Tips 12 Ways Holiday Song Healthy Living Check-Ups are Important Check- ... Test Wash Hands Stay Warm Have a Healthy Holiday Don’t Drink and Drive Widgets Healthy People ...

Tip off the HAT– Epigenetic control of learning and memory by Drosophila Tip60

PubMed Central

Xu, Songjun; Elefant, Felice

2015-01-01

Disruption of epigenetic gene control mechanisms involving histone acetylation in the brain causes cognitive impairment, a debilitating hallmark of most neurodegenerative disorders. Histone acetylation regulates cognitive gene expression via chromatin packaging control in neurons. Unfortunately, the histone acetyltransferases (HATs) that generate such neural epigenetic signatures and their mechanisms of action remain unclear. Our recent findings provide insight into this question by demonstrating that Tip60 HAT action is critical for morphology and function of the mushroom body (MB), the learning and memory center in the Drosophila brain. We show that Tip60 is robustly produced in MB Kenyon cells and extending axonal lobes and that targeted MB Tip60 HAT loss results in axonal outgrowth disruption. Functional consequences of loss and gain of Tip60 HAT levels in the MB are evidenced by defects in memory. Tip60 ChIP-Seq analysis reveals enrichment for genes that function in cognitive processes and accordingly, key genes representing these pathways are misregulated in the Tip60 HAT mutant fly brain. Remarkably, increasing levels of Tip60 in the MB rescues learning and memory deficits resulting from Alzheimer's disease associated amyloid precursor protein (APP) induced neurodegeneration. Our studies highlight the potential of HAT activators as a therapeutic option for cognitive disorders. PMID:26327426

Advanced turbine blade tip seal system

NASA Technical Reports Server (NTRS)

Zelahy, J. W.

1981-01-01

An advanced blade/shroud system designed to maintain close clearance between blade tips and turbine shrouds and at the same time, be resistant to environmental effects including high temperature oxidation, hot corrosion, and thermal cycling is described. Increased efficiency and increased blade life are attained by using the advanced blade tip seal system. Features of the system include improved clearance control when blade tips preferentially wear the shrouds and a superior single crystal superalloy tip. The tip design, joint location, characterization of the single crystal tip alloy, the abrasive tip treatment, and the component and engine test are among the factors addressed. Results of wear testing, quality control plans, and the total manufacturing cycle required to fully process the blades are also discussed.

Total Telephone Tips.

ERIC Educational Resources Information Center

Corder, Lloyd E.; And Others

This manual of telephone behavior tips for business and sales professionals offers ways to handle the disgruntled caller and makes suggestions on topics relevant to the telephone. The manual is divided into the following sections and subsections: (1) Common Courtesy (staff tips, answering the telephone, screening calls, transferring calls, taking…

Media Monday tip sheet builds Spartanburg's media relations.

PubMed

Rees, Tom

2005-01-01

Media Monday is published weekly and sent to area newsrooms by the Spartanburg Regional Healthcare System, Spartanburg, S.C. The news and feature tip sheet was started in 1998 in order to disperse a lot of information with a limited number of staff.

Ten tips for receiving feedback effectively in clinical practice

PubMed Central

Algiraigri, Ali H.

2014-01-01

Background Despite being recognized as a fundamental part of the educational process and emphasized for several decades in medical education, the influence of the feedback process is still suboptimal. This may not be surprising, because the focus is primarily centered on only one half of the process – the teachers. The learners are the targets of the feedback process and improvement needs to be shifted. Learners need to be empowered with the skills needed to receive and utilize feedback and compensate for less than ideal feedback delivery due to the busy clinical environment. Methods Based on the available feedback literature and clinical experience regarding feedback, the author developed 10 tips to empower learners with the necessary skills to seek, receive, and handle feedback effectively, regardless of how it is delivered. Although, most of the tips are directed at the individual clinical trainee, this model can be utilized by clinical educators involved in learner development and serve as a framework for educational workshops or curriculum. Results Ten practical tips are identified that specifically address the learner's role in the feedback process. These tips not only help the learner to ask, receive, and handle the feedback, but will also ease the process for the teachers. Collectively, these tips help to overcome most, if not all, of the barriers to feedback and bridge the gaps in busy clinical practices. Conclusions Feedback is a crucial element in the educational process and it is shown that we are still behind in the optimal use of it; thus, learners need to be taught how to better receive and utilize feedback. The focus in medical education needs to balance the two sides of the feedback process. It is time now to invest on the learner's development of skills that can be utilized in a busy day-to-day clinical practice. PMID:25079664

Ergonomic Factors Related to Drop-Off Detection With the Long Cane: Effects of Cane Tips and Techniques

PubMed Central

Kim, Dae Shik; Wall Emerson, Robert S.; Curtis, Amy B.

2010-01-01

Objective This study examined the effect of cane tips and cane techniques on drop-off detection with the long cane. Background Blind pedestrians depend on a long cane to detect drop-offs. Missing a drop-off may result in falls or collision with moving vehicles in the street. Although cane tips appear to affect a cane user’s ability to detect drop-offs, few experimental studies have examined such effect. Method A repeated-measures design with block randomization was used for the study. Participants were 17 adults who were legally blind and had no other disabilities. Participants attempted to detect the drop-offs of varied depths using different cane tips and cane techniques. Results Drop-off detection rates were similar between the marshmallow tip (77.0%) and the marshmallow roller tip (79.4%) when both tips were used with the constant contact technique, p = .294. However, participants detected drop-offs at a significantly higher percentage when they used the constant contact technique with the marshmallow roller tip (79.4%) than when they used the two-point touch technique with the marshmallow tip (63.2%), p < .001. Conclusion The constant contact technique used with a marshmallow roller tip (perceived as a less advantageous tip) was more effective than the two-point touch technique used with a marshmallow tip (perceived as a more advantageous tip) in detecting drop-offs. Application The findings of the study may help cane users and orientation and mobility specialists select appropriate cane techniques and cane tips in accordance with the cane user’s characteristics and the nature of the travel environment. PMID:21077566

Scanning tip microwave near field microscope

DOEpatents

Xiang, Xiao-Dong; Schultz, Peter G.; Wei, Tao

1998-01-01

A microwave near field microscope has a novel microwave probe structure wherein the probing field of evanescent radiation is emitted from a sharpened metal tip instead of an aperture or gap. This sharpened tip, which is electrically and mechanically connected to a central electrode, extends through and beyond an aperture in an endwall of a microwave resonating device such as a microwave cavity resonator or a microwave stripline resonator. Since the field intensity at the tip increases as the tip sharpens, the total energy which is radiated from the tip and absorbed by the sample increases as the tip sharpens. The result is improved spatial resolution without sacrificing sensitivity.

Staffing Preschools: Background Information.

ERIC Educational Resources Information Center

Katz, Lilian G.; Weir, Mary K.

This report explores background variables related to preschool teaching, and emphasizes that statistics fluctuate in early childhood education. The increase for preprimary enrollment of 3- and 4-year-olds was 26 percent from 1966 to 1967. Accurate figures on preschool teaching personnel are not available, but a large proportion of Head Start…

For Men: Tips for Good Health in Later Life

MedlinePlus

For Men: Tips for Good Health in Later Life Expert information from Healthcare Professionals Who Specialize in the Care ... Americans are living longer than ever, but American men still aren’t living as long as American ...

Finite Element Model and Validation of Nasal Tip Deformation

PubMed Central

Manuel, Cyrus T; Harb, Rani; Badran, Alan; Ho, David; Wong, Brian JF

2016-01-01

Nasal tip mechanical stability is important for functional and cosmetic nasal airway surgery. Palpation of the nasal tip provides information on tip strength to the surgeon, though it is a purely subjective assessment. Providing a means to simulate nasal tip deformation with a validated model can offer a more objective approach in understanding the mechanics and nuances of the nasal tip support and eventual nasal mechanics as a whole. Herein we present validation of a finite element (FE) model of the nose using physical measurements recorded using an ABS plastic-silicone nasal phantom. Three-dimensional photogrammetry was used to capture the geometry of the phantom at rest and while under steady state load. The silicone used to make the phantom was mechanically tested and characterized using a linear elastic constitutive model. Surface point clouds of the silicone and FE model were compared for both the loaded and unloaded state. The average Hausdorff distance between actual measurements and FE simulations across the nose were 0.39mm ± 1.04 mm and deviated up to 2mm at the outermost boundaries of the model. FE simulation and measurements were in near complete agreement in the immediate vicinity of the nasal tip with millimeter accuracy. We have demonstrated validation of a two-component nasal FE model, which could be used to model more complex modes of deformation where direct measurement may be challenging. This is the first step in developing a nasal model to simulate nasal mechanics and ultimately the interaction between geometry and airflow. PMID:27633018

Finite Element Model and Validation of Nasal Tip Deformation.

PubMed

Manuel, Cyrus T; Harb, Rani; Badran, Alan; Ho, David; Wong, Brian J F

2017-03-01

Nasal tip mechanical stability is important for functional and cosmetic nasal airway surgery. Palpation of the nasal tip provides information on tip strength to the surgeon, though it is a purely subjective assessment. Providing a means to simulate nasal tip deformation with a validated model can offer a more objective approach in understanding the mechanics and nuances of the nasal tip support and eventual nasal mechanics as a whole. Herein we present validation of a finite element (FE) model of the nose using physical measurements recorded using an ABS plastic-silicone nasal phantom. Three-dimensional photogrammetry was used to capture the geometry of the phantom at rest and while under steady state load. The silicone used to make the phantom was mechanically tested and characterized using a linear elastic constitutive model. Surface point clouds of the silicone and FE model were compared for both the loaded and unloaded state. The average Hausdorff distance between actual measurements and FE simulations across the nose were 0.39 ± 1.04 mm and deviated up to 2 mm at the outermost boundaries of the model. FE simulation and measurements were in near complete agreement in the immediate vicinity of the nasal tip with millimeter accuracy. We have demonstrated validation of a two-component nasal FE model, which could be used to model more complex modes of deformation where direct measurement may be challenging. This is the first step in developing a nasal model to simulate nasal mechanics and ultimately the interaction between geometry and airflow.

Turbine blade with contoured chamfered squealer tip

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ching-Pang

2014-12-30

A squealer tip formed from a pressure side tip wall and a suction side tip wall extending radially outward from a tip of the turbine blade is disclosed. The pressure and suction side tip walls may be positioned along the pressure sidewall and the suction sidewall of the turbine blade, respectively. The pressure side tip wall may include a chamfered leading edge with film cooling holes having exhaust outlets positioned therein. An axially extending tip wall may be formed from at least two outer linear surfaces joined together at an intersection forming a concave axially extending tip wall. The axiallymore » extending tip wall may include a convex inner surface forming a radially outer end to an inner cavity forming a cooling system. The cooling system may include one or more film cooling holes in the axially extending tip wall proximate to the suction sidewall, which promotes increased cooling at the pressure and suction sidewalls.« less

Slender tip laser scalpel

DOEpatents

Veligdan, James T.

2004-01-06

A laser scalpel includes a ribbon optical waveguide extending therethrough and terminating at a slender optical cutting tip. A laser beam is emitted along the height of the cutting tip for cutting tissue therealong.

Scanning tip microwave near field microscope

DOEpatents

Xiang, X.D.; Schultz, P.G.; Wei, T.

1998-10-13

A microwave near field microscope has a novel microwave probe structure wherein the probing field of evanescent radiation is emitted from a sharpened metal tip instead of an aperture or gap. This sharpened tip, which is electrically and mechanically connected to a central electrode, extends through and beyond an aperture in an end wall of a microwave resonating device such as a microwave cavity resonator or a microwave stripline resonator. Since the field intensity at the tip increases as the tip sharpens, the total energy which is radiated from the tip and absorbed by the sample increases as the tip sharpens. The result is improved spatial resolution without sacrificing sensitivity. 17 figs.

Temporal Information Processing as a Basis for Auditory Comprehension: Clinical Evidence from Aphasic Patients

ERIC Educational Resources Information Center

Oron, Anna; Szymaszek, Aneta; Szelag, Elzbieta

2015-01-01

Background: Temporal information processing (TIP) underlies many aspects of cognitive functions like language, motor control, learning, memory, attention, etc. Millisecond timing may be assessed by sequencing abilities, e.g. the perception of event order. It may be measured with auditory temporal-order-threshold (TOT), i.e. a minimum time gap…

Tips for Teachers of Evidence-based Medicine: Clinical Prediction Rules (CPRs) and Estimating Pretest Probability

PubMed Central

McGinn, Thomas; Jervis, Ramiro; Wisnivesky, Juan; Keitz, Sheri

2008-01-01

Background Clinical prediction rules (CPR) are tools that clinicians can use to predict the most likely diagnosis, prognosis, or response to treatment in a patient based on individual characteristics. CPRs attempt to standardize, simplify, and increase the accuracy of clinicians’ diagnostic and prognostic assessments. The teaching tips series is designed to give teachers advice and materials they can use to attain specific educational objectives. Educational Objectives In this article, we present 3 teaching tips aimed at helping clinical learners use clinical prediction rules and to more accurately assess pretest probability in every day practice. The first tip is designed to demonstrate variability in physician estimation of pretest probability. The second tip demonstrates how the estimate of pretest probability influences the interpretation of diagnostic tests and patient management. The third tip exposes learners to various examples and different types of Clinical Prediction Rules (CPR) and how to apply them in practice. Pilot Testing We field tested all 3 tips with 16 learners, a mix of interns and senior residents. Teacher preparatory time was approximately 2 hours. The field test utilized a board and a data projector; 3 handouts were prepared. The tips were felt to be clear and the educational objectives reached. Potential teaching pitfalls were identified. Conclusion Teaching with these tips will help physicians appreciate the importance of applying evidence to their every day decisions. In 2 or 3 short teaching sessions, clinicians can also become familiar with the use of CPRs in applying evidence consistently in everyday practice. PMID:18491194

Gap-mode enhancement on MoS2 probed by functionalized tip-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Alajlan, Abdulrahman M.; Voronine, Dmitri V.; Sinyukov, Alexander M.; Zhang, Zhenrong; Sokolov, Alexei V.; Scully, Marlan O.

2016-09-01

Surface enhancement of molecular spectroscopic signals has been widely used for sensing and nanoscale imaging. Because of the weak electromagnetic enhancement of Raman signals on semiconductors, it is motivating but challenging to study the electromagnetic effect separately from the chemical effects. We report tip-enhanced Raman scattering measurements on Au and bulk MoS2 substrates using a metallic tip functionalized with copper phthalocyanine molecules and demonstrate similar gap-mode enhancement on both substrates. We compare the experimental results with theoretical calculations to confirm the gap-mode enhancement on MoS2 using a well-established electrostatic model. The functionalized tip approach allows for suppressing the background and is ideal for separating electromagnetic and chemical enhancement mechanisms on various substrates. Our results may find a wide range of applications in MoS2-based devices, sensors, and metal-free nanoscale bio-imaging.

Testing of a Microwave Blade Tip Clearance Sensor at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Woike, Mark R.; Roeder, James W.; Hughes, Christopher E.; Bencic, Timothy J.

2009-01-01

The development of new active tip clearance control and structural health monitoring schemes in turbine engines and other types of rotating machinery requires sensors that are highly accurate and can operate in a high-temperature environment. The use of a microwave sensor to acquire blade tip clearance and tip timing measurements is being explored at the NASA Glenn Research Center. The microwave blade tip clearance sensor works on principles that are very similar to a short-range radar system. The sensor sends a continuous microwave signal towards a target and measures the reflected signal. The phase difference of the reflected signal is directly proportional to the distance between the sensor and the target being measured. This type of sensor is beneficial in that it has the ability to operate at extremely high temperatures and is unaffected by contaminants that may be present in turbine engines. The use of microwave sensors for this application is a new concept. Techniques on calibrating the sensors along with installation effects are not well quantified as they are for other sensor technologies. Developing calibration techniques and evaluating installation effects are essential in using these sensors to make tip clearance and tip timing measurements. As a means of better understanding these issues, the microwave sensors were used on a benchtop calibration rig, a large axial vane fan, and a turbofan. Background on the microwave tip clearance sensor, an overview of their calibration, and the results from their use on the axial vane fan and the turbofan will be presented in this paper.

Testing of a Microwave Blade Tip Clearance Sensor at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Woike, Mark R.; Roeder, James W.; Hughes, Christopher E.; Bencic, Timothy J.

2009-01-01

The development of new active tip clearance control and structural health monitoring schemes in turbine engines and other types of rotating machinery requires sensors that are highly accurate and can operate in a high temperature environment. The use of a microwave sensor to acquire blade tip clearance and tip timing measurements is being explored at the NASA Glenn Research Center. The microwave blade tip clearance sensor works on principles that are very similar to a short range radar system. The sensor sends a continuous microwave signal towards a target and measures the reflected signal. The phase difference of the reflected signal is directly proportional to the distance between the sensor and the target being measured. This type of sensor is beneficial in that it has the ability to operate at extremely high temperatures and is unaffected by contaminants that may be present in turbine engines. The use of microwave sensors for this application is a new concept. Techniques on calibrating the sensors along with installation effects are not well quantified as they are for other sensor technologies. Developing calibration techniques and evaluating installation effects are essential in using these sensors to make tip clearance and tip timing measurements. As a means of better understanding these issues, the microwave sensors were used on a bench top calibration rig, a large axial vane fan, and a turbofan. Background on the microwave tip clearance sensor, an overview of their calibration, and the results from their use on the axial vane fan and the turbofan will be presented in this paper.

Chemically etched fiber tips for near-field optical microscopy: a process for smoother tips.

PubMed

Lambelet, P; Sayah, A; Pfeffer, M; Philipona, C; Marquis-Weible, F

1998-11-01

An improved method for producing fiber tips for scanning near-field optical microscopy is presented. The improvement consists of chemically etching quartz optical fibers through their acrylate jacket. This new method is compared with the previous one in which bare fibers were etched. With the new process the meniscus formed by the acid along the fiber does not move during etching, leading to a much smoother surface of the tip cone. Subsequent metallization is thus improved, resulting in better coverage of the tip with an aluminum opaque layer. Our results show that leakage can be avoided along the cone, and light transmission through the tip is spatially limited to an optical aperture of a 100-nm dimension.

Tips for using mobile audience response systems in medical education

PubMed Central

Gousseau, Michael; Sommerfeld, Connor; Gooi, Adrian

2016-01-01

Background With growing evidence on the benefits of active learning, audience response systems (ARSs) have been increasingly used in conferences, business, and education. With the introduction of mobile ARS as an alternative to physical clickers, there are increasing opportunities to use this tool to improve interactivity in medical education. Aim The aim of this study is to provide strategies on using mobile ARS in medical education by discussing steps for implementation and pitfalls to avoid. Method The tips presented reflect our commentary of the literature and our experiences using mobile ARS in medical education. Results This article offers specific strategies for the preparation, implementation, and assessment of medical education teaching sessions using mobile ARS. Conclusion We hope these tips will help instructors use mobile ARS as a tool to improve student interaction, teaching effectiveness, and participant enjoyment in medical education. PMID:27942242

Renal papillary tip extract stimulates BNP production and excretion from cardiomyocytes

PubMed Central

Hashizume, Ryotaro; Suzuki, Noboru; Ito, Rie; Yamanaka, Keiichi; Saito, Hiromitsu; Kiyonari, Hiroshi; Tawara, Isao; Kageyama, Yuki; Ogihara, Yoshito; Ali, Yusuf; Yamada, Norikazu; Katayama, Naoyuki; Ito, Masaaki

2018-01-01

Background Brain natriuretic peptide (BNP) is an important biomarker for patients with cardiovascular diseases, including heart failure, hypertension and cardiac hypertrophy. It is also known that BNP levels are relatively higher in patients with chronic kidney disease and no heart disease; however, the mechanism remains unclear. Methods and results We developed a BNP reporter mouse and occasionally found that this promoter was activated specifically in the papillary tip of the kidneys, and its activation was not accompanied by BNP mRNA expression. No evidence was found to support the existence of BNP isoforms or other nucleotide expression apart from BNP and tdTomato. The pBNP-tdTomato-positive cells were interstitial cells and were not proliferative. Unexpectedly, both the expression and secretion of BNP increased in primary cultured neonatal cardiomyocytes after their treatment with an extract of the renal papillary tip. Intraperitoneal injection of the extract of the papillary tips reduced blood pressure from 210 mmHg to 165 mmHg, the decrease being accompanied by an increase in serum BNP and urinary cGMP production in stroke-prone spontaneously hypertensive (SHR-SP) rats. Furthermore the induction of BNP by the papillary extract from rats with heart failure due to myocardial infarction was increased in cardiomyocytes. Conclusions These results suggested that the papillary tip express a substance that can stimulate BNP production and secretion from cardiomyocytes. PMID:29734386

ADHD: Tips to Try

MedlinePlus

... Staying Safe Videos for Educators Search English Español ADHD: Tips to Try KidsHealth / For Teens / ADHD: Tips to Try Print en español TDAH: Consejos que puedes probar ADHD , short for attention deficit hyperactivity disorder , is a ...

Acquisition of background and technical information and class trip planning

NASA Technical Reports Server (NTRS)

Mackinnon, R. M.; Wake, W. H.

1981-01-01

Instructors who are very familiar with a study area, as well as those who are not, find the field trip information acquisition and planning process speeded and made more effective by organizing it in stages. The stage follow a deductive progression: from the associated context region, to the study area, to the specific sample window sites, and from generalized background information on the study region to specific technical data on the environmental and human use systems to be interpreted at each site. On the class trip and in the follow up laboratory, the learning/interpretive process are at first deductive in applying previously learned information and skills to analysis of the study site, then inductive in reading and interpreting the landscape, imagery, and maps of the site, correlating them with information of other samples sites and building valid generalizations about the larger study area, its context region, and other (similar and/or contrasting) regions.

Effects of Double-Leakage Tip Clearance Flow on the Performance of a Compressor Stage with a Large Rotor Tip Gap

NASA Technical Reports Server (NTRS)

Hah, Chunill

2016-01-01

Effects of a large rotor tip gap on the performance of a one and half stage axial compressor are investigated in detail with a numerical simulation based on LES and available PIV data. The current paper studies the main flow physics, including why and how the loss generation is increased with the large rotor tip gap. The present study reveals that when the tip gap becomes large, tip clearance fluid goes over the tip clearance core vortex and enters into the next blade's tip gap, which is called double-leakage tip clearance flow. As the tip clearance flow enters into the adjacent blade's tip gap, a vortex rope with a lower pressure core is generated. This vortex rope breaks up the tip clearance core vortex of the adjacent blade, resulting in a large additional mixing. This double-leakage tip clearance flow occurs at all operating conditions, from design flow to near stall condition, with the large tip gap for the current compressor stage. The double-leakage tip clearance flow, its interaction with the tip clearance core vortex of the adjacent blade, and the resulting large mixing loss are the main flow mechanism of the large rotor tip gap in the compressor. When the tip clearance is smaller, flow near the end wall follows more closely with the main passage flow and this double-leakage tip clearance flow does not happen near the design flow condition for the current compressor stage. When the compressor with a large tip gap operates at near stall operation, a strong vortex rope is generated near the leading edge due to the double-leakage flow. Part of this vortex separates from the path of the tip clearance core vortex and travels from the suction side of the blade toward the pressure side of the blade. This vortex is generated periodically at near stall operation with a large tip gap. As the vortex travels from the suction side to the pressure side of the blade, a large fluctuation of local pressure forces blade vibration. Nonsynchronous blade vibration occurs due

Recall and Believability of the Tips from Former Smokers Campaign among University Students

ERIC Educational Resources Information Center

Ickes, Melinda. J.; Butler, Karen; Rayens, Mary Kay; Noland, Melody; Wiggins, Amanda T.; Hahn, Ellen J.

2016-01-01

Background: Tobacco media campaigns are effective, but less is known regarding the impact on college students. Purpose: The purpose was to test the effects of an on-campus Tips television campaign on frequency and believability of ads recalled and to assess demographic and personal factors associated with believability. Methods: A…

[Effects of exposure frequency and background information on preferences for photographs of cars in different locations].

PubMed

Matsuda, Ken; Kusumi, Takashi; Hosomi, Naohiro; Osa, Atsushi; Miike, Hidetoshi

2014-08-01

This study examined the influence of familiarity and novelty on the mere exposure effect while manipulating the presentation of background information. We selected presentation stimuli that integrated cars and backgrounds based on the results of pilot studies. During the exposure phase, we displayed the stimuli successively for 3 seconds, manipulating the background information (same or different backgrounds with each presentation) and exposure frequency (3, 6, and 9 times). In the judgment phase, 18 participants judged the cars in terms of preference, familiarity, and novelty on a 7-point scale. As the number of stimulus presentations increased, the preference for the cars increased during the different background condition and decreased during the same background condition. This increased preference may be due to the increase in familiarity caused by the higher exposure frequency and novelty resulting from the background changes per exposure session. The rise in preference judgments was not seen when cars and backgrounds were presented independently. Therefore, the addition of novel features to each exposure session facilitated the mere exposure effect.

Tax Tips for Forest Landowners for the 2013 Tax Year

Treesearch

Linda Wang; John Greene

2013-01-01

This annual bulletin provides federal income tax reporting tips to assist forest landowners and their advisers in filing their 2013 income tax returns. The information presented here is current as of Sept. 15, 2013.

Magnet pole tips

DOEpatents

Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

1984-04-24

An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

Magnet pole tips

DOEpatents

Thorn, C.E.; Chasman, C.; Baltz, A.J.

1981-11-19

An improved magnet more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

Gas only nozzle fuel tip

DOEpatents

Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

2002-01-01

A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozzle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

The Micro TIPS - Cases - Programmed Learning Course Package.

ERIC Educational Resources Information Center

Heriot-Watt Univ., Edinburgh (Scotland). Esmee Fairbairn Economics Research Centre.

Part of an economic education series, the course package is designed to teach basic concepts and principles of microeconomics and how they can be applied to various world problems. For use with college students, learning is gained through lectures, tutorials, textbooks, programmed text, cases, and TIPS (Teaching Information Processing System).…

Astronaut Harbaugh on middeck with messages from TIPS

NASA Image and Video Library

1995-07-10

STS071-122-018 (27 June-7 July 1995) --- Astronaut Gregory J. Harbaugh, STS-71 mission specialist, is pictured on the space shuttle Atlantis' middeck, with a roll of messages from the Thermal Imaging Printing System (TIPS). The volume of information had been up-linked by ground controllers in Houston, Texas.

Nasal Sculpting: Calculated and Predictable Tip Elevation With Cephalic Trim

PubMed Central

Redstone, Jeremiah S.; Nguyen, Jonathan; North, Durham Alan; Hazani, Ron; Drury, Brad; Yoder, Eric M.; Cooperman, Ross D.; Yoder, Virginia; Little, Jarrod A.; Florman, Larry D.; Wilhelmi, Bradon J.

2015-01-01

Background: Rhinoplasty techniques to affect nasal tip rotation are well described. Cephalic alar trim is a powerful method for achieving tip elevation. Previous studies and texts provide aesthetic guidelines for nasolabial angles. Often, surgeon experience determines the degree of lower lateral cartilage resection to achieve optimal results. This study analyzes the change in tip elevation with measured resections of the lower lateral cartilages. This can aid the surgeon in accurately predicting the effect of cephalic alar trim on tip elevation. Methods: Ten fresh cadaveric dissections were performed to determine the change in nasolabial angles after cephalic trim of the lower lateral cartilage. Closed rhinoplasty technique was performed using marginal and intercartilaginous incisions to expose the lower lateral cartilage. Caliper measurements of the lower lateral cartilage were recorded. Serial cephalic trim was performed in 25% increments. True lateral photographs were obtained before and after each serial excision. Nasolabial angle measurements were obtained using a digital goniometer for digital photo analysis. Results: Four female and 6 male cadavers were evaluated. The mean initial nasolabial angle was 106° ± 2°. The mean lower lateral cartilage width was 9.45 ± 1.38 mm. Serial 25% reductions in lower lateral cartilage height resulted in a mean total nasolabial angle change of 7.4°, 12.9°, and 19.6°, respectively. The mean incremental change in the nasolabial angle was 6.47° ± 1.25°. Conclusion: The nasolabial angle is an essential aesthetic feature. Cephalic trim is a key maneuver in affecting the nasolabial angle. A 25% lower lateral cartilage cephalic trim correlates with an average change in the nasolabial angle of 6.47°. Knowledge of the cephalic trim to nasolabial angle relationship aids in achieving desired tip elevation. PMID:26171091

Families with Special Needs: Caregiving Tips

MedlinePlus

... Halloween Prom Tips Spring Break Valentine Tips Winter Holiday Tips 12 Ways Holiday Song Healthy Living Check-Ups are Important Check- ... Test Wash Hands Stay Warm Have a Healthy Holiday Don’t Drink and Drive Widgets Healthy People ...

Social Media Tips to Enhance Medical Education.

PubMed

Shah, Vikas; Kotsenas, Amy L

2017-06-01

In this article, we describe how social media can supplement traditional education, articulate the advantages and disadvantages of various social media platforms for both teachers and learners, discuss best practices to maintain confidentiality of protected health information, and provide tips for implementing social media-based teaching into the training curriculum. Copyright © 2017 The Association of University Radiologists. All rights reserved.

Tip cap for a rotor blade

NASA Technical Reports Server (NTRS)

Kofel, W. K.; Tuley, E. N.; Gay, C. H., Jr.; Troeger, R. E.; Sterman, A. P. (Inventor)

1983-01-01

A replaceable tip cap for attachment to the end of a rotor blade is described. The tip cap includes a plurality of walls defining a compartment which, if desired, can be divided into a plurality of subcompartments. The tip cap can include inlet and outlet holes in walls thereof to permit fluid communication of a cooling fluid there through. Abrasive material can be attached with the radially outer wall of the tip cap.

Association between Media Doses of the "Tips from Former Smokers" Campaign and Cessation Behaviors and Intentions to Quit among Cigarette Smokers, 2012-2015

ERIC Educational Resources Information Center

Davis, Kevin C.; Patel, Deesha; Shafer, Paul; Duke, Jennifer; Glover-Kudon, Rebecca; Ridgeway, William; Cox, Shanna

2018-01-01

Background: Since 2012, the Centers for Disease Control and Prevention (CDC) has implemented "Tips From Former Smokers" ("Tips"), the first federally funded tobacco education campaign in the United States. To date, there are no evaluations of its long-term impact. Aims: To assess the impact of varied doses of the…

TipMT: Identification of PCR-based taxon-specific markers.

PubMed

Rodrigues-Luiz, Gabriela F; Cardoso, Mariana S; Valdivia, Hugo O; Ayala, Edward V; Gontijo, Célia M F; Rodrigues, Thiago de S; Fujiwara, Ricardo T; Lopes, Robson S; Bartholomeu, Daniella C

2017-02-11

Molecular genetic markers are one of the most informative and widely used genome features in clinical and environmental diagnostic studies. A polymerase chain reaction (PCR)-based molecular marker is very attractive because it is suitable to high throughput automation and confers high specificity. However, the design of taxon-specific primers may be difficult and time consuming due to the need to identify appropriate genomic regions for annealing primers and to evaluate primer specificity. Here, we report the development of a Tool for Identification of Primers for Multiple Taxa (TipMT), which is a web application to search and design primers for genotyping based on genomic data. The tool identifies and targets single sequence repeats (SSR) or orthologous/taxa-specific genes for genotyping using Multiplex PCR. This pipeline was applied to the genomes of four species of Leishmania (L. amazonensis, L. braziliensis, L. infantum and L. major) and validated by PCR using artificial genomic DNA mixtures of the Leishmania species as templates. This experimental validation demonstrates the reliability of TipMT because amplification profiles showed discrimination of genomic DNA samples from Leishmania species. The TipMT web tool allows for large-scale identification and design of taxon-specific primers and is freely available to the scientific community at http://200.131.37.155/tipMT/ .

Taxicab tipping and sunlight

PubMed Central

2017-01-01

Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences. PMID:28594917

Taxicab tipping and sunlight.

PubMed

Devaraj, Srikant; Patel, Pankaj C

2017-01-01

Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences.

Early warning of climate tipping points

NASA Astrophysics Data System (ADS)

Lenton, Timothy M.

2011-07-01

A climate 'tipping point' occurs when a small change in forcing triggers a strongly nonlinear response in the internal dynamics of part of the climate system, qualitatively changing its future state. Human-induced climate change could push several large-scale 'tipping elements' past a tipping point. Candidates include irreversible melt of the Greenland ice sheet, dieback of the Amazon rainforest and shift of the West African monsoon. Recent assessments give an increased probability of future tipping events, and the corresponding impacts are estimated to be large, making them significant risks. Recent work shows that early warning of an approaching climate tipping point is possible in principle, and could have considerable value in reducing the risk that they pose.

Distinguishing vegetation from soil background information. [by gray mapping of Landsat MSS data

NASA Technical Reports Server (NTRS)

Richardson, A. J.; Wiegand, C. L.

1977-01-01

In aircraft and satellite multispectral scanner data, soil background signals are superimposed on or intermingled with information about vegetation. A procedure which accounts for soil background would, therefore, make a considerable contribution to an operational use of Landsat and other spectral data for monitoring the productivity of range, forest, and crop lands. A description is presented of an investigation which was conducted to obtain information for the development of such a procedure. The investigation included a study of the soil reflectance that supplies the background signal of vegetated surfaces. Landsat data as recorded on computer compatible tapes were used in the study. The results of the investigation are discussed, taking into account a study reported by Kauth and Thomas (1976). Attention is given to the determination of Kauth's plane of soils, sun angle effects, vegetation index modeling, and the evaluation of vegetation indexes. Graphs are presented which show the results obtained with a gray mapping technique. The technique makes it possible to display plant, soil, water, and cloud conditions for any Landsat overpass.

A remarkably stable TipE gene cluster: evolution of insect Para sodium channel auxiliary subunits

PubMed Central

2011-01-01

Background First identified in fruit flies with temperature-sensitive paralysis phenotypes, the Drosophila melanogaster TipE locus encodes four voltage-gated sodium (NaV) channel auxiliary subunits. This cluster of TipE-like genes on chromosome 3L, and a fifth family member on chromosome 3R, are important for the optional expression and functionality of the Para NaV channel but appear quite distinct from auxiliary subunits in vertebrates. Here, we exploited available arthropod genomic resources to trace the origin of TipE-like genes by mapping their evolutionary histories and examining their genomic architectures. Results We identified a remarkably conserved synteny block of TipE-like orthologues with well-maintained local gene arrangements from 21 insect species. Homologues in the water flea, Daphnia pulex, suggest an ancestral pancrustacean repertoire of four TipE-like genes; a subsequent gene duplication may have generated functional redundancy allowing gene losses in the silk moth and mosquitoes. Intronic nesting of the insect TipE gene cluster probably occurred following the divergence from crustaceans, but in the flour beetle and silk moth genomes the clusters apparently escaped from nesting. Across Pancrustacea, TipE gene family members have experienced intronic nesting, escape from nesting, retrotransposition, translocation, and gene loss events while generally maintaining their local gene neighbourhoods. D. melanogaster TipE-like genes exhibit coordinated spatial and temporal regulation of expression distinct from their host gene but well-correlated with their regulatory target, the Para NaV channel, suggesting that functional constraints may preserve the TipE gene cluster. We identified homology between TipE-like NaV channel regulators and vertebrate Slo-beta auxiliary subunits of big-conductance calcium-activated potassium (BKCa) channels, which suggests that ion channel regulatory partners have evolved distinct lineage-specific characteristics

An investigation of tip planform influence on the aerodynamic load characteristics of semispan, upswept wing and wing-tip

NASA Technical Reports Server (NTRS)

Vanaken, Johannes M.

1986-01-01

A semi-span wing, equipped with an interchangeable tip, which was varied in planform and size was examined. Total wing aerodynamic loading was obtained from the wind tunnel scale system. The wing tip was mounted on a separate six-component strain gauge balance, which provided the aerodynamic loads on the tip. The tests were accomplished in the NASA Ames 7X10-Foot Wind Tunnel at a Mach number of 0.178. The aerodynamic load characteristics of the wing and of the tip were presented with the tip at several incidence angles relative to the wing inboard section.

Turbine blade squealer tip rail with fence members

DOE Office of Scientific and Technical Information (OSTI.GOV)

Little, David A

2012-11-20

A turbine blade includes an airfoil, a blade tip section, a squealer tip rail, and a plurality of chordally spaced fence members. The blade tip section includes a blade tip floor located at an end of the airfoil distal from the root. The blade tip floor includes a pressure side and a suction side joined together at chordally spaced apart leading and trailing edges of the airfoil. The squealer tip rail extends radially outwardly from the blade tip floor adjacent to the suction side and extends from a first location adjacent to the airfoil trailing edge to a second locationmore » adjacent to the airfoil leading edge. The fence members are located between the airfoil leading and trailing edges and extend radially outwardly from the blade tip floor and axially from the squealer tip rail toward the pressure side.« less

29 CFR 516.28 - Tipped employees.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Tipped employees. 516.28 Section 516.28 Labor Regulations... EMPLOYERS Records Pertaining to Employees Subject to Miscellaneous Exemptions Under the Act; Other Special Requirements § 516.28 Tipped employees. (a) With respect to each tipped employee whose wages are determined...

Plasmonic Colloidal Nanoantennas for Tip-Enhanced Raman Spectrocopy

NASA Astrophysics Data System (ADS)

Dill, Tyler J.

Plasmonic nanoantennas that a support localized surface plasmon resonance (LSPR) are capable of confining visible light to subwavelength dimensions due to strong electromagnetic field enhancement at the probe tip. Nanoantenna enable optical methods such as tip-enhanced Raman spectroscopy (TERS), a technique that uses scanning probe microscopy tips to provide chemical information with nanoscale spatial resolution and single-molecule sensitivities. The LSPR supported by the probe tip is extremely sensitive to the nanoscale morphology of the nanoantenna. Control of nanoscale morphology is notoriously difficult to achieve, resulting in TERS probes with poor reproducibility. In my thesis, I demonstrate high-performance, predictable, and broadband nanospectroscopy probes that are fabricated by self-assembly. Shaped metal nanoparticles are organized into dense layers and deposited onto scanning probe tips. When coupled to a metal substrate, these probes support a strong optical resonance in the gap between the substrate and the probe, producing dramatic field enhancements. I show through experiment and electromagnetic modeling that close-packed but electrically isolated nanoparticles are electromagnetically coupled. Hybridized LSPRs supported by self-assembled nanoparticles with a broadband optical response, giving colloidal nanoantenna a high tolerance for geometric variation resulting from fabrication. I find that coupled nanoparticles act as a waveguide, transferring energy from many neighboring nanoparticles towards the active TERS apex. I also use surface-enhanced Raman spectroscopy (SERS) to characterize the effects of nanoparticle polydispersity and gap height on the Raman enhancement. These colloidal probes have consistently achieved dramatic Raman enhancements in the range of 108-109 with sub-50 nm spatial resolution. Furthermore, in contrast to other nanospectroscopy probes, these colloidal probes can be fabricated in a scalable fashion with a batch

Normal and variant anatomy of the nasal tip.

PubMed

Ketcham, Amy S; Dobratz, Eric J

2012-04-01

A thorough understanding of nasal tip anatomy is a prerequisite to understanding the nuances of restructuring the nasal tip. The three-dimensional structural anatomy of the nasal tip is complex. Additionally, the interrelationship between these structures determines the ultimate form and function of the nasal tip. As a result, alteration of one structure in the tip will often lead to change in other portions of the nasal tip. This dynamic concept of anatomy in the nasal tip makes proper alteration of the nasal tip one of the most challenging tasks faced by a rhinoplasty surgeon. This article provides a fundamental knowledge of the normal anatomy of the tip structures and how their interaction with each other determines the shape and support of the lower portion of the nose. It also provides a description of some common variants of tip anatomy that cause patients to seek consultation for rhinoplasty. A proper understanding of the concepts presented provides a foundation to build on as the reader continues to explore the "nuances of the nasal tip." Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Imaging of soft material with carbon nanotube tip using near-field scanning microwave microscopy.

PubMed

Wu, Zhe; Sun, Wei-Qiang; Feng, Tao; Tang, Shawn Wenjie; Li, Gang; Jiang, Kai-Li; Xu, Sheng-Yong; Ong, Chong Kim

2015-01-01

In this manuscript, a near-field scanning microwave microscope (NSMM) of our own design is introduced while using a multi-walled carbon nanotube (MWCNT) bundle as the tip (referred to as 'CNT tip'). Clear images of gold-patterned numbers, photoresist stripes and corneal endothelial cells (cell line B4G12) were obtained by mapping the resonant frequency fr and S11 amplitude of a given area while the NSMM is operating in tapping mode. The CNT tip helps to improve image quality and reveals more information about the sample as compared to a traditional metallic tip. The CNT tip is flexible and does not scratch the surface of the sample during the scan, which is useful for imaging soft material in biological science. In the imaging of the B4G12 endothelial cells, the nuclei and cytoplasm can be clearly distinguished from the rest of the cell and its surrounding medium. Copyright © 2014 Elsevier B.V. All rights reserved.

Ten tips for successful electronic health records deployment.

PubMed

Gasch, Art

2012-01-01

As healthcare providers are increasingly compelled to adopt electronic health records (EHRs) and paper records migrate to electronic files provided to dozens of healthcare intermediaries, breeches of protected health information are skyrocketing, and so are dissatisfaction rates with EHR solutions. This article provides 10 practical tips to ensure a successful EHR system deployment an circumvent EHR land mines.

Southwestern Pine Tip Moth

Treesearch

Daniel T. Jennings; Robert E. Stevens

1982-01-01

The southwestern pine tip moth, Rhyacionia neomexicana (Dyar), injures young ponderosa pines (Pinus ponderosa Dougl. ex Laws) in the Southwest, central Rockies, and midwestern plains. Larvae feed on and destroy new, expanding shoots, often seriously reducing terminal growth of both naturally regenerated and planted pines. The tip moth is especially damaging to trees on...

Web-based Tailored Intervention for Preparation of Parents and Children for Outpatient Surgery (WebTIPS): Development

PubMed Central

Kain, Zeev N.; Fortier, Michelle A.; Chorney, Jill MacLaren; Mayes, Linda

2014-01-01

Background Due to cost-containment efforts, preparation programs for outpatient surgery are currently not available to the majority of children and parents. The recent dramatic growth in the Internet presents a unique opportunity to transform how children and their parents are prepared for surgery. In this article we describe the development of a Web-based tailored preparation program for children and parents undergoing surgery (WebTIPS). Development of Program A multidisciplinary taskforce agreed that a Web-based tailored intervention comprised of intake, matrix and output modules was the preferred approach. Next, the content of the various intake variables, the matrix logic and the output content was developed. The output product has a parent component and a child component and is described in http://surgerywebtips.com/about.php. The child component makes use of preparation strategies such as information provision, modeling, play and coping skills training. The parent component of WebTIPS includes strategies such as information provision, coping skills training, relaxation and distraction techniques. A reputable animation and Web-design company developed a secured Web-based product based on the above description. Conclusions In this article we describe the development of a Web-based tailored preoperative preparation program that can be accessed by children and parents multiple times before and after surgery. A follow-up article in this issue of Anesthesia & Analgesia describes formative evaluation and preliminary efficacy testing of this Web-based tailored preoperative preparation program. PMID:25790212

An optical fiber bundle sensor for tip clearance and tip timing measurements in a turbine rig.

PubMed

García, Iker; Beloki, Josu; Zubia, Joseba; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Jiménez, Felipe

2013-06-05

When it comes to measuring blade-tip clearance or blade-tip timing in turbines, reflective intensity-modulated optical fiber sensors overcome several traditional limitations of capacitive, inductive or discharging probe sensors. This paper presents the signals and results corresponding to the third stage of a multistage turbine rig, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on the turbine casing. To eliminate the influence of light source intensity variations and blade surface reflectivity, the sensing principle is based on the quotient of the voltages obtained from the two receiving bundle legs. A discrepancy lower than 3% with respect to a commercial sensor was observed in tip clearance measurements. Regarding tip timing measurements, the travel wave spectrum was obtained, which provides the average vibration amplitude for all blades at a particular nodal diameter. With this approach, both blade-tip timing and tip clearance measurements can be carried out simultaneously. The results obtained on the test turbine rig demonstrate the suitability and reliability of the type of sensor used, and suggest the possibility of performing these measurements in real turbines under real working conditions.

An Optical Fiber Bundle Sensor for Tip Clearance and Tip Timing Measurements in a Turbine Rig

PubMed Central

García, Iker; Beloki, Josu; Zubia, Joseba; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Jiménez, Felipe

2013-01-01

When it comes to measuring blade-tip clearance or blade-tip timing in turbines, reflective intensity-modulated optical fiber sensors overcome several traditional limitations of capacitive, inductive or discharging probe sensors. This paper presents the signals and results corresponding to the third stage of a multistage turbine rig, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on the turbine casing. To eliminate the influence of light source intensity variations and blade surface reflectivity, the sensing principle is based on the quotient of the voltages obtained from the two receiving bundle legs. A discrepancy lower than 3% with respect to a commercial sensor was observed in tip clearance measurements. Regarding tip timing measurements, the travel wave spectrum was obtained, which provides the average vibration amplitude for all blades at a particular nodal diameter. With this approach, both blade-tip timing and tip clearance measurements can be carried out simultaneously. The results obtained on the test turbine rig demonstrate the suitability and reliability of the type of sensor used, and suggest the possibility of performing these measurements in real turbines under real working conditions. PMID:23739163

Teaching Tip: Adding Intercultural Communication to an IS Curriculum

ERIC Educational Resources Information Center

Mitchell, Alanah; Benyon, Rob

2018-01-01

Increasingly, today's information systems (IS) programs are focused on making sure students are graduating with well-developed soft skills. One of these necessary soft skills is intercultural communication, which is the ability to communicate with people from different cultures. This teaching tip presents an assignment designed to increase the…

Chemical composition of felt-tip pen inks.

PubMed

Germinario, Giulia; Garrappa, Silvia; D'Ambrosio, Valeria; van der Werf, Inez Dorothé; Sabbatini, Luigia

2018-01-01

Felt-tip pens are frequently used for the realization of sketches, drawings, architectural projects, and other technical designs. The formulations of these inks are usually rather complex and may be associated to those of modern paint materials where, next to the binding medium and pigments/dyes, solvents, fillers, emulsifiers, antioxidants, plasticizers, light stabilizers, biocides, and so on are commonly added. Felt-tip pen inks are extremely sensitive to degradation and especially exposure to light may cause chromatic changes and fading. In this study, we report on the complete chemical characterization of modern felt-tip pen inks that are commercially available and commonly used for the realization of artworks. Three brands of felt-tip pens (Faber-Castell, Edding, and Stabilo) were investigated with complementary analytical techniques such as thin-layer chromatography (TLC), VIS-reflectance spectroscopy, μ-Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), GC-MS, and Fourier transform infrared (FTIR) spectroscopy. The use of TLC proved to be very powerful in the study of complex mixtures of synthetic dyes. First derivatives of the reflectance spectra acquired on the TLC spots were useful in the preliminary identification of the dye, followed by Raman spectroscopy and SERS, which allowed for the unambiguous determination of the chemical composition of the pigments (phthalocyanines, dioxazines, and azo pigments) and dyes (azo dyes, triarylmethanes, xanthenes). FTIR spectroscopy was used especially for the detection of additives, as well as for confirming the nature of solvents and dyes/pigments. Finally, (Py-)GC-MS data provided information on the binders (styrene-acrylic resins, plant gums), solvents, and additives, as well as on pigments and dyes.

Sirt1 physically interacts with Tip60 and negatively regulates Tip60-mediated acetylation of H2AX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamagata, Kazutsune, E-mail: kyamagat@ncc.go.jp; Kitabayashi, Issay

2009-12-25

Sirt1 appear to be NAD(+)-dependent deacetylase that deacetylates histones and several non-histone proteins. In this study, we identified Sirt1 as a physical interaction partner of Tip60, which is a mammalian MYST-type histone acetyl-transferase that specifically acetylates histones H2A and H4. Although Tip60 also acetylates DNA damage-specific histone H2A variant H2AX in response to DNA damage, which is a process required for appropriate DNA damage response, overexpression of Sirt1 represses Tip60-mediated acetylation of H2AX. Furthermore, Sirt1 depletion by RNAi causes excessive acetylation of H2AX, and enhances accumulation of {gamma}-ray irradiation-induced MDC1, BRCA1, and Rad51 foci in nuclei. These findings suggest thatmore » Sirt1 functions as negative regulator of Tip60-mediated acetylation of H2AX. Moreover, Sirt1 deacetylates an acetylated Tip60 in response to DNA damage and stimulates proteasome-dependent Tip60 degradation in vivo, suggesting that Sirt1 negatively regulates the protein level of Tip60 in vivo. Sirt1 may thus repress excessive activation of the DNA damage response and Rad51-homologous recombination repair by suppressing the function of Tip60.« less

Tip-Enhanced Raman Scattering Imaging of Two-Dimensional Tungsten Disulfide with Optimized Tip Fabrication Process.

PubMed

Lee, Chanwoo; Kim, Sung Tae; Jeong, Byeong Geun; Yun, Seok Joon; Song, Young Jae; Lee, Young Hee; Park, Doo Jae; Jeong, Mun Seok

2017-01-13

We successfully achieve the tip-enhanced nano Raman scattering images of a tungsten disulfide monolayer with optimizing a fabrication method of gold nanotip by controlling the concentration of etchant in an electrochemical etching process. By applying a square-wave voltage supplied from an arbitrary waveform generator to a gold wire, which is immersed in a hydrochloric acid solution diluted with ethanol at various ratios, we find that both the conical angle and radius of curvature of the tip apex can be varied by changing the ratio of hydrochloric acid and ethanol. We also suggest a model to explain the origin of these variations in the tip shape. From the systematic study, we find an optimal condition for achieving the yield of ~60% with the radius of ~34 nm and the cone angle of ~35°. Using representative tips fabricated under the optimal etching condition, we demonstrate the tip-enhanced Raman scattering experiment of tungsten disulfide monolayer grown by a chemical vapor deposition method with a spatial resolution of ~40 nm and a Raman enhancement factor of ~4,760.

Tipping elements in the Earth's climate system.

PubMed

Lenton, Timothy M; Held, Hermann; Kriegler, Elmar; Hall, Jim W; Lucht, Wolfgang; Rahmstorf, Stefan; Schellnhuber, Hans Joachim

2008-02-12

The term "tipping point" commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system. Here we introduce the term "tipping element" to describe large-scale components of the Earth system that may pass a tipping point. We critically evaluate potential policy-relevant tipping elements in the climate system under anthropogenic forcing, drawing on the pertinent literature and a recent international workshop to compile a short list, and we assess where their tipping points lie. An expert elicitation is used to help rank their sensitivity to global warming and the uncertainty about the underlying physical mechanisms. Then we explain how, in principle, early warning systems could be established to detect the proximity of some tipping points.

Sensor tip for a robotic gripper and method of manufacture

NASA Technical Reports Server (NTRS)

Lorenz, Robert D. (Inventor); Jackson, Gregory T. (Inventor)

1991-01-01

A sensor tip (10) for use in a robotic hand has a three-dimensional compliant elastomeric body (12) with an outer boundary (22) having a circular base (24) and a convex surface (26) extending therefrom. Four strain transducers (14, 16, 18, and 20) produce electrical signals indicative of the strain at various positions near the boundary of the elastomeric body (12) resulting from forces exerted upon the sensor tip (10) by an object which the robotic hand is manipulating. The transducers (14, 16, 18, and 20) are positioned about the convex surface (26) so as to produce signals that may be decoupled to determine the normal and tangential forces and the applied torque. A buffer amplifier circuit (34), one for each of the transducers (14, 16, 18, and 20), receives the signals and provides quasi-steady state force information. The circuit (34) connects the respective transducer (40) in a feedback loop around an amplifier (36) and has desirable attributes for static charge buffering. The sensor tip (10) is calibrated to determine proportionality constants for the decoupling algorithm for use of a force delivering system (60), which uses voice coils (74) to apply a force that is linearly related to the current introduced to each of the coils (74). A method of manufacture of the sensor tip (10) results in improved bonding between the transducers (14, 16, 18, and 20) and the elastomeric body (12) for better performance and longer life of the sensor tip (10).

Sensor tip for a robotic gripper and method of manufacture

NASA Technical Reports Server (NTRS)

Lorenz, Robert D. (Inventor); Jackson, Gregory T. (Inventor)

1993-01-01

A sensor tip (10) for use in a robotic hand has a three-dimensional compliant elastomeric body (12) with an outer boundary (22) having a circular base (24) and a convex surface (26) extending therefrom. Four strain transducers (14, 16, 18, and 20) produce electrical signals indicative of the strain at various positions near the boundary of the elastomeric body (12) resulting from forces exerted upon the sensor tip (10) by an object which the robotic hand is manipulating. The transducers (14, 16, 18, and 20) are positioned about the convex surface (26) so as to produce signals that may be decoupled to determine the normal and tangential forces and the applied torque. A buffer amplifier circuit (34), one for each of the transducers (14, 16, 18, and 20), receives the signals and provides quasi-steady state force information. The circuit (34) connects the respective transducer (40) in a feedback loop around an amplifier (36) and has desirable attributes for static charge buffering. The sensor tip (10) is calibrated to determine proportionality constants for the decoupling algorithm for use of a force delivering system (60), which uses voice coils (74) to apply a force that is linearly related to the current introduced to each of the coils (74). A method of manufacture of the sensor tip (10) results in improved bonding between the transducers (14, 16, 18, and 20) and the elastomeric body (12) for better performance and longer life of the sensor tip (10).

Oxygen-Free Welding Contact Tips

NASA Technical Reports Server (NTRS)

Pike, James F.

1993-01-01

Contact tips for gas/metal arc welding (GMAW) fabricated from oxygen-free copper. Prototype tips tested in robotic welding, for which application intended. Reduces electrical erosion, increases electrical conductivity, and reduces mechanical wear. Productivity of robotic welding increases while time during welding interrupted for removal and replacement of contact tips minimal. Improves alignment of joints and filler metal, reducing rate of rejection and repair of unacceptable weldments. Utility extends beyond aerospace industry to mass production of various types of hardware, including heavy off-highway construction equipment.

With Protein Foods, Variety Is Key: 10 Tips for Choosing Protein

MedlinePlus

... or seeds can be considered as 1 ounce-equivalent from the Protein Foods Group. Revised January 2016 ... Us Advanced Search Help Search Tips Privacy Policy Non-Discrimination Statement Information Quality USA.gov WhiteHouse.gov

Privacy Impact Assessment for the Application for Tips and Complaints

EPA Pesticide Factsheets

The Application for Tips and Complaints System collects information on potential violators. Learn how this data is collected in the system, how it will be used, access to the data, the purpose of data collection, and record retention policies for this data

Low photon-count tip-tilt sensor

NASA Astrophysics Data System (ADS)

Saathof, Rudolf; Schitter, Georg

2016-07-01

Due to the low photon-count of dark areas of the universe, signal strength of tip-tilt sensor is low, limiting sky-coverage of reliable tip-tilt measurements. This paper presents the low photon-count tip-tilt (LPC-TT) sensor, which potentially achieves improved signal strength. Its optical design spatially samples and integrates the scene. This increases the probability that several individual sources coincide on a detector segment. Laboratory experiments show feasibility of spatial sampling and integration and the ability to measure tilt angles. By simulation an improvement of the SNR of 10 dB compared to conventional tip-tilt sensors is shown.

RANS computations of tip vortex cavitation

NASA Astrophysics Data System (ADS)

Decaix, Jean; Balarac, Guillaume; Dreyer, Matthieu; Farhat, Mohamed; Münch, Cécile

2015-12-01

The present study is related to the development of the tip vortex cavitation in Kaplan turbines. The investigation is carried out on a simplified test case consisting of a NACA0009 blade with a gap between the blade tip and the side wall. Computations with and without cavitation are performed using a R ANS modelling and a transport equation for the liquid volume fraction. Compared with experimental data, the R ANS computations turn out to be able to capture accurately the development of the tip vortex. The simulations have also highlighted the influence of cavitation on the tip vortex trajectory.

Tipping elements in the Earth's climate system

PubMed Central

Lenton, Timothy M.; Held, Hermann; Kriegler, Elmar; Hall, Jim W.; Lucht, Wolfgang; Rahmstorf, Stefan; Schellnhuber, Hans Joachim

2008-01-01

The term “tipping point” commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system. Here we introduce the term “tipping element” to describe large-scale components of the Earth system that may pass a tipping point. We critically evaluate potential policy-relevant tipping elements in the climate system under anthropogenic forcing, drawing on the pertinent literature and a recent international workshop to compile a short list, and we assess where their tipping points lie. An expert elicitation is used to help rank their sensitivity to global warming and the uncertainty about the underlying physical mechanisms. Then we explain how, in principle, early warning systems could be established to detect the proximity of some tipping points. PMID:18258748

Biophysical Characterization of the Type III Secretion Tip Proteins and the Tip Proteins Attached to Bacterium-Like Particles

PubMed Central

Choudhari, Shyamal P.; Chen, Xiaotong; Kim, Jae Hyun; van Roosmalen, Maarten L.; Greenwood, Jamie C.; Joshi, Sangeeta B.; Picking, William D.; Leenhouts, Kees; Middaugh, C. Russell; Picking, Wendy L.

2014-01-01

Bacterium-like particles (BLPs), derived from Lactococcus lactis, offer a self-adjuvanting delivery vehicle for subunit protein vaccines. Proteins can be specifically loaded onto the BLPs via a peptidoglycan anchoring domain (PA). In this study, the tip proteins IpaD, SipD and LcrV belonging to type three secretion systems of Shigella flexneri, Salmonella enterica and Yersinia enterocolitica, respectively, were fused to the PA and loaded onto the BLPs. Herein, we biophysically characterized these nine samples and condensed the spectroscopic results into three-index empirical phase diagrams (EPDs). The EPDs show distinctions between the IpaD/SipD and LcrV subfamilies of tip proteins, based on their physical stability, even upon addition of the PA. Upon attachment to the BLPs, the BLPs become defining moiety in the spectroscopic measurements, leaving the tip proteins to have a subtle yet modulating effect on the structural integrity of the tip proteins-BLPs binding. In summary, this work provides a comprehensive view of physical stability of the tip proteins and tip protein-BLPs and serves as a baseline for screening of excipients to increase the stability of the tip protein-BLPs for future vaccine formulation. PMID:24916512

Stochastic integrated assessment of climate tipping points indicates the need for strict climate policy

NASA Astrophysics Data System (ADS)

Lontzek, Thomas S.; Cai, Yongyang; Judd, Kenneth L.; Lenton, Timothy M.

2015-05-01

Perhaps the most `dangerous’ aspect of future climate change is the possibility that human activities will push parts of the climate system past tipping points, leading to irreversible impacts. The likelihood of such large-scale singular events is expected to increase with global warming, but is fundamentally uncertain. A key question is how should the uncertainty surrounding tipping events affect climate policy? We address this using a stochastic integrated assessment model, based on the widely used deterministic DICE model. The temperature-dependent likelihood of tipping is calibrated using expert opinions, which we find to be internally consistent. The irreversible impacts of tipping events are assumed to accumulate steadily over time (rather than instantaneously), consistent with scientific understanding. Even with conservative assumptions about the rate and impacts of a stochastic tipping event, today’s optimal carbon tax is increased by ~50%. For a plausibly rapid, high-impact tipping event, today’s optimal carbon tax is increased by >200%. The additional carbon tax to delay climate tipping grows at only about half the rate of the baseline carbon tax. This implies that the effective discount rate for the costs of stochastic climate tipping is much lower than the discount rate for deterministic climate damages. Our results support recent suggestions that the costs of carbon emission used to inform policy are being underestimated, and that uncertain future climate damages should be discounted at a low rate.

Aerodynamic tip desensitization in axial flow turbines

NASA Astrophysics Data System (ADS)

Dey, Debashis

The leakage flow near the tip of unshrouded rotor blades in axial turbines imposes significant thermal loads on the blade. It is also responsible for up to a third of aerodynamic losses in a turbine stage. The leakage flow, mainly induced by the pressure differential across the rotor tip section, usually rolls into a stream-wise vertical structure near the suction side part of the blade tip. The current study uses several concepts to reduce the severity of losses introduced by the leakage vortex. Three tip desensitization techniques, both active and passive, are examined. Coolant flow from a tip trench is used to counter the momentum of the leakage jet. Next, a very short winglet obtained by slightly extending the tip platform in the tangential direction is investigated. Lastly, the widely used concept of squealer tip is studied. The current investigation is performed in the Axial Flow Turbine Research Facility (AFTRF) of the Pennsylvania State University. Rotating frame five hole probe measurements as well as stationary frame phase averaged total pressure measurements downstream of a single stage turbine facility were taken. The study enables one to draw conclusions about the nature of the flowfield in the rotor tip region. It also shows that significant efficiency gains could be obtained by using some of these techniques.

Radiofrequency Wire Recanalization of Chronically Thrombosed TIPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Majdalany, Bill S., E-mail: bmajdala@med.umich.edu; Elliott, Eric D., E-mail: eric.elliott@osumc.edu; Michaels, Anthony J., E-mail: Anthony.michaels@osumc.edu

Radiofrequency (RF) guide wires have been applied to cardiac interventions, recanalization of central venous thromboses, and to cross biliary occlusions. Herein, the use of a RF wire technique to revise chronically occluded transjugular intrahepatic portosystemic shunts (TIPS) is described. In both cases, conventional TIPS revision techniques failed to revise the chronically thrombosed TIPS. RF wire recanalization was successfully performed through each of the chronically thrombosed TIPS, demonstrating initial safety and feasibility in this application.

Tips for Good Electronic Presentations.

ERIC Educational Resources Information Center

Strasser, Dennis

1996-01-01

Describes library uses of presentation graphics software and offers tips for creating electronic presentations. Tips include: audience retention; visual aid options; software package options; presentation planning; presentation showing; and use of text, colors, and graphics. Sidebars note common presentation errors and popular presentation…

An experimental investigation of free-tip response to a jet

NASA Technical Reports Server (NTRS)

Young, L. A.

1986-01-01

The aerodynamic response of passively oscillating tips appended to a model helicopter rotor was investigated during a whirl test. Tip responsiveness was found to meet free-tip rotor requirements. Experimental and analytical estimates of the free-tip aerodynamic spring, mechanical spring, and aerodynamic damping were calculated and compared. The free tips were analytically demonstrated to be operating outside the tip resonant response region at full-scale tip speeds. Further, tip resonance was shown to be independent of tip speed, given the assumption that the tip forcing frequency is linearly dependent upon the rotor rotational speed.

Tipping Points in Texas Rivers

NASA Astrophysics Data System (ADS)

Phillips, Jonathan

2016-04-01

Anticipating geomorphic tipping points requires that we learn from the past. Major geomorphic changes in coastal plain rivers of Texas resulting in river metamorphosis or regime shifts were identified, and the major driving factors determined. Nine fluvial tipping points were identified from contemporary observations, historical records, and Quaternary reconstructions. Two of the tipping points (between general aggrading and degrading valley states) are associated with reversals in a fundamental system control (sea-level). One (stable or aggrading vs. degrading channels) is associated with an abrupt change in sediment supply due to dam construction, and two others (changes from meandering to anastomosing channel patterns, and different anastomosis styles) are similarly related to changes in sediment supply and/or transport capacity, but with additional elements of historical contingency. Three tipping points are related to avulsions. One, from a regime dominated to reoccupation of former channels to one dominated by progradation into flood basins, is driven by progressive long term filling of incised valleys. Another, nodal avulsions, are driven by disturbances associated with tectonics or listric faults. The third, avulsions and related valley metamorphosis in unfilled incised valleys, is due to fundamental dynamical instabilities within the fluvial system. This synthesis and analysis suggests that geomorphic tipping points are sometimes associated with general extrinsic or intrinsic (to the fluvial system) environmental change, independent of any disturbances or instabilities. Others are associated with natural (e.g., tectonic) or human (dams) disturbances, and still others with intrinsic geomorphic instabilities. This suggests that future tipping points will be equally diverse with respect to their drivers.

Terahertz Nanofocusing with Cantilevered Terahertz-Resonant Antenna Tips.

PubMed

Mastel, Stefan; Lundeberg, Mark B; Alonso-González, Pablo; Gao, Yuanda; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Koppens, Frank H L; Nikitin, Alexey Y; Hillenbrand, Rainer

2017-11-08

We developed THz-resonant scanning probe tips, yielding strongly enhanced and nanoscale confined THz near fields at their tip apex. The tips with length in the order of the THz wavelength (λ = 96.5 μm) were fabricated by focused ion beam (FIB) machining and attached to standard atomic force microscopy (AFM) cantilevers. Measurements of the near-field intensity at the very tip apex (25 nm radius) as a function of tip length, via graphene-based (thermoelectric) near-field detection, indicate their first and second order geometrical antenna resonances for tip length of 33 and 78 μm, respectively. On resonance, we find that the near-field intensity is enhanced by one order of magnitude compared to tips of 17 μm length (standard AFM tip length), which is corroborated by numerical simulations that further predict remarkable intensity enhancements of about 10 7 relative to the incident field. Because of the strong field enhancement and standard AFM operation of our tips, we envision manifold and straightforward future application in scattering-type THz near-field nanoscopy and THz photocurrent nanoimaging, nanoscale nonlinear THz imaging, or nanoscale control and manipulation of matter employing ultrastrong and ultrashort THz pulses.

Tip cap for a turbine rotor blade

DOEpatents

Kimmel, Keith D

2014-03-25

A turbine rotor blade with a spar and shell construction, and a tip cap that includes a row of lugs extending from a bottom side that form dovetail grooves that engage with similar shaped lugs and grooves on a tip end of the spar to secure the tip cap to the spar against radial displacement. The lug on the trailing edge end of the tip cap is aligned perpendicular to a chordwise line of the blade in the trailing edge region in order to minimize stress due to the lugs wanting to bend under high centrifugal loads. A two piece tip cap with lugs at different angles will reduce the bending stress even more.

Efficacy of air/water syringe tip sterilization.

PubMed

Inger, M; Bennani, V; Farella, M; Bennani, F; Cannon, R D

2014-03-01

Dental procedures involve contact between instruments and the patient's tissues, blood or saliva. This study evaluated the efficacy of the standardized sterilization of non-disposable air/water syringe tips and corrosion and contaminant build-up in these tips. The bacterial contamination of single-use and multiple-use non-disposable air/water syringe tips after routine use and sterilization was compared to that of single-use disposable tips by microbial culturing on PCA and blood agar plates. The effect of flushing the syringe tips prior to sterilization was also measured. The amount of corrosion in single-use and multiple-use non-disposable syringes was measured by SEM and EDS analyses. Non-disposable syringe tips had significantly (p < 0.05) greater bacterial contamination than single-use disposable tips. There were no statistically different levels of contamination between flushed and non-flushed non-disposable syringes or between single-use and multiple-use non-disposable syringes. SEM and EDS analyses showed greater evidence of corrosion and contaminant build-up in multiple-use syringes compared to single-use non-disposable syringes. Sterilization of non-disposable air/water syringes is not completely effective and rinsing, or the number of uses, does not affect the effectiveness of sterilization. There may be a lower risk of cross-infection from the use of disposable air/water syringe tips, instead of non-disposable ones. © 2014 Australian Dental Association.

Tip/tilt-compensated through-focus scanning optical microscopy

NASA Astrophysics Data System (ADS)

Lee, Jun Ho; Park, Jun Hyung; Jeong, Dohwan; Shin, Eun Ji; Park, Chris

2016-11-01

Through-Focus Optical Microscopy (TSOM), with nanometer scale lateral and vertical sensitivity matching those of scanning electron microscopy, has been demonstrated to be utilized for 3D inspection and metrology. There have been sensitivity and instability issues in acquiring through-focus images because TSOM 3D information is indirectly extracted by differentiating a target TSOM image from reference TSOM images. This paper first reports on the optical axis instability that occurs during the scanning process of TSOM when implemented in an existing patterned wafer inspection tool by moving the wafer plane; this is followed by quantitative confirmation of the optical/mechanical instability using a new TSOM tool on an optical bench with a Shack-Hartmann wavefront sensor and a tip/tilt sensor. Then, this paper proposes two tip/tilt compensated TSOM optical acquisition methods that can be applied with adaptive optics. The first method simply adopts a tip/tilt mirror with a quad cell in a simple closed loop, while the second method adopts a highorder deformable mirror with a Shack-Hartmann sensor. The second method is able to correct high-order residual aberrations as well as to perform through-focus scanning without z-axis movement, while the first method is easier to implement in pre-existing wafer inspection systems with only minor modification.

Active Piezoelectric Structures for Tip Clearance Management Assessed

NASA Technical Reports Server (NTRS)

1995-01-01

Managing blade tip clearance in turbomachinery stages is critical to developing advanced subsonic propulsion systems. Active casing structures with embedded piezoelectric actuators appear to be a promising solution. They can control static and dynamic tip clearance, compensate for uneven deflections, and accomplish electromechanical coupling at the material level. In addition, they have a compact design. To assess the feasibility of this concept and assist the development of these novel structures, the NASA Lewis Research Center developed in-house computational capabilities for composite structures with piezoelectric actuators and sensors, and subsequently used them to simulate candidate active casing structures. The simulations indicated the potential of active casings to modify the blade tip clearance enough to improve stage efficiency. They also provided valuable design information, such as preliminary actuator configurations (number and location) and the corresponding voltage patterns required to compensate for uneven casing deformations. An active ovalization of a casing with four discrete piezoceramic actuators attached on the outer surface is shown. The center figure shows the predicted radial displacements along the hoop direction that are induced when electrostatic voltage is applied at the piezoceramic actuators. This work, which has demonstrated the capabilities of in-house computational models to analyze and design active casing structures, is expected to contribute toward the development of advanced subsonic engines.

Comparison of different types of phacoemulsification tips. I. Quantitative analysis of elemental composition and tip surface microroughness.

PubMed

Tsaousis, Konstantinos T; Werner, Liliana; Perez, Jesus Paulo; Li, He J; Reiter, Nicholas; Guan, Jia J; Mamalis, Nick

2016-09-01

To evaluate the elemental composition of phacoemulsification tips and their surface roughness in the microscale. John A. Moran Eye Center and Utah Nanofab, College of Engineering, University of Utah, Salt Lake City, Utah, USA. Experimental study. Seven types of phacoemulsification tips were studied. The phaco tips were examined through energy-dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) for elemental composition. In addition, the roughness of the opening in all tips was assessed through 3-dimensional white-light interferometry. Elemental analysis showed considerable differences in the surface layers between manufacturers. Alcon tips had a thinner oxidized titanium (Ti) layer in their surface. Through XPS, vanadium was not detected in the superficial layers of any tip, but only in deeper levels. The microroughness surface analysis showed comparable results regarding their root-mean-square (RMS) metric. Maximum peak valley distance values varied and appeared to be dependent on the quality of material process rather than the material itself. Phacoemulsification tips are made of Ti alloys and showed differences between models, especially regarding their composition in the superficial layers. Their opening end roughness showed an overall appropriate RMS value of less than 1.0 μm in all cases. The existence of small defected areas highlights the importance of adequate quality control of these critical surgical instruments. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Mapping cavitation activity around dental ultrasonic tips.

PubMed

Walmsley, A Damien; Lea, Simon C; Felver, Bernhard; King, David C; Price, Gareth J

2013-05-01

Cavitation arising within the water around the oscillating ultrasonic scaler tip is an area that may lead to advances in enhancing biofilm removal. The aim of this study is to map the occurrence of cavitation around scaler tips under loaded conditions. Two designs of piezoelectric ultrasonic scaling probes were evaluated with a scanning laser vibrometer and luminol dosimetric system under loaded (100 g/200 g) and unloaded conditions. Loads were applied to the probe tips via teeth mounted in a load-measuring apparatus. There was a positive correlation between probe displacement amplitude and cavitation production for ultrasonic probes. The position of cavitation at the tip of each probe was greater under loaded conditions than unloaded and for the longer P probe towards the tip. Whilst increasing vibration displacement amplitude of ultrasonic scalers increases the occurrence of cavitation, factors such as the length of the probe influence the amount of cavitation activity generated. The application of load affects the production of cavitation at the most clinically relevant area-the tip. Loading and the design of ultrasonic scalers lead to maximising the occurrence of the cavitation at the tip and enhance the cleaning efficiency of the scaler.

[TIPS

PubMed

Brazzini, Augusto; Carrillo, Alvaro; Cantella, Raúl

1998-01-01

Esophageal hemorrage due to variceal bleeding in cirrhotic patients represents a serious problem for the physician in charge, especially in this country where liver transplants are inexistent; and also, it is a drama for the patient and its familly. We propose here the Transjugular Intrahepatic Portosystemic Shunt (TIPS). Twenty one patients were part of a study where 23 TIPS were placed, observing an immediate improval in 18 of them, a rebleeding in 2, within the first 24 and 48 hours. An embolization of the coronary veins was performed in the procedure in 15 patients, and a second intervention due to rebleeding in 2 of them. In the latter patients, the embolization of the coronary veins was rutinary.The survival of the patients has been outstanding.We conclude that this interventional procedure is a worldwide reality in the treatment of esophageal hemorrage by variceal bleeding due to portal hipertension, and it does not cut down the probability of liver transplant, unfortunately inexistent in our country. This procedure results in a low morbimortality with an adequate quality of life.

On the development of a magnetoresistive sensor for blade tip timing and blade tip clearance measurement systems

NASA Astrophysics Data System (ADS)

Tomassini, R.; Rossi, G.; Brouckaert, J.-F.

2014-05-01

The accurate control of the gap between static and rotating components is vital to preserve the mechanical integrity and ensure a correct functioning of any rotating machinery. Moreover, tip leakage above the airfoil tip results in relevant aerodynamic losses. One way to measure and to monitor blade tip gaps is by the so-called Blade Tip Clearance (BTC) technique. Another fundamental phenomenon to control in the turbomachines is the vibration of the blades. For more than half a century, this has been performed by installing strain gauges on the blades and using telemetry to transmit the signals. The Blade Tip Timing (BTT) technique, (i.e. measuring the blade time of arrival from the casing at different angular locations with proximity sensors) is currently being adopted by all manufacturers as a replacement for the classical strain gauge technique because of its non-intrusive character. This paper presents a novel magnetoresistive sensor for blade tip timing and blade tip clearance systems, which offers high temporal and high spatial resolution simultaneously. The sensing element adopted is a Wheatstone bridge of Permalloy elements. The principle of the sensor is based on the variation of magnetic field at the passage of ferromagnetic objects. Two different configurations have been realized, a digital and an analogue sensor. Measurements of tip clearance have been performed in an high speed compressor and the calibration curve is reported. Measurements of blade vibration have been carried out in a dedicated calibration bench; results are presented and discussed. The magnetoresistive sensor is characterized by high repeatability, low manufacturing costs and measurement accuracy in line with the main probes used in turbomachinery testing. The novel sensor has great potential and is capable of fulfilling the requirements for a simultaneous BTC and BTT measurement system.

The tonoplast intrinsic aquaporin (TIP) subfamily of Eucalyptus grandis: Characterization of EgTIP2, a root-specific and osmotic stress-responsive gene.

PubMed

Rodrigues, Marcela I; Bravo, Juliana P; Sassaki, Flávio T; Severino, Fábio E; Maia, Ivan G

2013-12-01

Aquaporins have important roles in various physiological processes in plants, including growth, development and adaptation to stress. In this study, a gene encoding a root-specific tonoplast intrinsic aquaporin (TIP) from Eucalyptus grandis (named EgTIP2) was investigated. The root-specific expression of EgTIP2 was validated over a panel of five eucalyptus organ/tissues. In eucalyptus roots, EgTIP2 expression was significantly induced by osmotic stress imposed by PEG treatment. Histochemical analysis of transgenic tobacco lines (Nicotiana tabacum SR1) harboring an EgTIP2 promoter:GUS reporter cassette revealed major GUS staining in the vasculature and in root tips. Consistent with its osmotic-stress inducible expression in eucalyptus, EgTIP2 promoter activity was up-regulated by mannitol treatment, but was down-regulated by abscisic acid. Taken together, these results suggest that EgTIP2 might be involved in eucalyptus response to drought. Additional searches in the eucalyptus genome revealed the presence of four additional putative TIP coding genes, which could be individually assigned to the classical TIP1-5 groups. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Arctic tipping points in an Earth system perspective.

PubMed

Wassmann, Paul; Lenton, Timothy M

2012-02-01

We provide an introduction to the volume The Arctic in the Earth System perspective: the role of tipping points. The terms tipping point and tipping element are described and their role in current science, general debates, and the Arctic are elucidated. From a wider perspective, the volume focuses upon the role of humans in the Arctic component of the Earth system and in particular the envelope for human existence, the Arctic ecosystems. The Arctic climate tipping elements, the tipping elements in Arctic ecosystems and societies, and the challenges of governance and anticipation are illuminated through short summaries of eight publications that derive from the Arctic Frontiers conference in 2011 and the EU FP7 project Arctic Tipping Points. Then some ideas based upon resilience thinking are developed to show how wise system management could ease pressures on Arctic systems in order to keep them away from tipping points.

Estimation of Nasal Tip Support Using Computer-Aided Design and 3-Dimensional Printed Models

PubMed Central

Gray, Eric; Maducdoc, Marlon; Manuel, Cyrus; Wong, Brian J. F.

2016-01-01

IMPORTANCE Palpation of the nasal tip is an essential component of the preoperative rhinoplasty examination. Measuring tip support is challenging, and the forces that correspond to ideal tip support are unknown. OBJECTIVE To identify the integrated reaction force and the minimum and ideal mechanical properties associated with nasal tip support. DESIGN, SETTING, AND PARTICIPANTS Three-dimensional (3-D) printed anatomic silicone nasal models were created using a computed tomographic scan and computer-aided design software. From this model, 3-D printing and casting methods were used to create 5 anatomically correct nasal models of varying constitutive Young moduli (0.042, 0.086, 0.098, 0.252, and 0.302 MPa) from silicone. Thirty rhinoplasty surgeons who attended a regional rhinoplasty course evaluated the reaction force (nasal tip recoil) of each model by palpation and selected the model that satisfied their requirements for minimum and ideal tip support. Data were collected from May 3 to 4, 2014. RESULTS Of the 30 respondents, 4 surgeons had been in practice for 1 to 5 years; 9 surgeons, 6 to 15 years; 7 surgeons, 16 to 25 years; and 10 surgeons, 26 or more years. Seventeen surgeons considered themselves in the advanced to expert skill competency levels. Logistic regression estimated the minimum threshold for the Young moduli for adequate and ideal tip support to be 0.096 and 0.154 MPa, respectively. Logistic regression estimated the thresholds for the reaction force associated with the absolute minimum and ideal requirements for good tip recoil to be 0.26 to 4.74 N and 0.37 to 7.19 N during 1- to 8-mm displacement, respectively. CONCLUSIONS AND RELEVANCE This study presents a method to estimate clinically relevant nasal tip reaction forces, which serve as a proxy for nasal tip support. This information will become increasingly important in computational modeling of nasal tip mechanics and ultimately will enhance surgical planning for rhinoplasty. LEVEL OF EVIDENCE

Compressor airfoil tip clearance optimization system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Little, David A.; Pu, Zhengxiang

2015-08-18

A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary.more » During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.« less

Tip-over Prevention: Adaptive Control Development

DTIC Science & Technology

2015-05-30

used to detect tip- over, with the FA and MHS metrics providing more effective stability measurements than the ZMP metric, in some cases indicating tip...support polygon formed by the robot’s ground contact points, as shown in Figure 1. If the Fig. 1. Tip-over angle definition in Force-Angle stability...0 (6) Therefore, the sum of the inertial, centripetal, Coriolis , and gravitational terms can be used to estimate the impact forces: fI,z = ω̇xry

Tips for Postpartum Dads and Partners

MedlinePlus

... Blues: Partners Interview with Wade Bowen Coping with Suicide & Loss Tips for Postpartum Dads and Partners Pregnancy and postpartum mood and anxiety disorders affect the whole family. Here are some tips ...

Integrated Turbine Tip Clearance and Gas Turbine Engine Simulation

NASA Technical Reports Server (NTRS)

Chapman, Jeffryes W.; Kratz, Jonathan; Guo, Ten-Huei; Litt, Jonathan

2016-01-01

Gas turbine compressor and turbine blade tip clearance (i.e., the radial distance between the blade tip of an axial compressor or turbine and the containment structure) is a major contributing factor to gas path sealing, and can significantly affect engine efficiency and operational temperature. This paper details the creation of a generic but realistic high pressure turbine tip clearance model that may be used to facilitate active tip clearance control system research. This model uses a first principles approach to approximate thermal and mechanical deformations of the turbine system, taking into account the rotor, shroud, and blade tip components. Validation of the tip clearance model shows that the results are realistic and reflect values found in literature. In addition, this model has been integrated with a gas turbine engine simulation, creating a platform to explore engine performance as tip clearance is adjusted. Results from the integrated model explore the effects of tip clearance on engine operation and highlight advantages of tip clearance management.

Sensitivity to Speaker Control in the Online Comprehension of Conditional Tips and Promises: An Eye-Tracking Study

ERIC Educational Resources Information Center

Stewart, Andrew J.; Haigh, Matthew; Ferguson, Heather J.

2013-01-01

Statements of the form if… then… can be used to communicate conditional speech acts such as tips and promises. Conditional promises require the speaker to have perceived control over the outcome event, whereas conditional tips do not. In an eye-tracking study, we examined whether readers are sensitive to information about perceived speaker control…

Dynamics of Isolated Tip Vortex Cavitation

NASA Astrophysics Data System (ADS)

Pennings, Pepijn; Bosschers, Johan; van Terwisga, Tom

2014-11-01

Performance of ship propellers and comfort levels in the surroundings are limited by various forms of cavitation. Amongst these forms tip vortex cavitation is one of the first appearing forms and is expected to be mainly responsible for the emission of broadband pressure fluctuations typically occurring between the 4th to the 7th blade passing frequency (approx. 40--70 Hz). These radiated pressure pulses are likely to excite parts of the hull structure resulting in a design compromise between efficiency and comfort. Insight is needed in the mechanism of acoustic emission from the oscillations by a tip vortex cavity. In the current experimental study the tip vortex cavity from a blade with an elliptic planform and sections based on NACA 662 - 415 with meanline a = 0 . 8 is observed using high speed shadowgraphy in combination with blade force and acoustic measurements. An analytic model describing three main cavity deformation modes is verified and used to explain the origin of a cavity eigenfrequency or ``vortex singing'' phenomenon observed by Maines and Arndt (1997) on the tip vortex cavity originating from the same blade. As no hydrodynamic sound originating from the tip vortex cavity was observed it is posed that a tip flow instability is essential for ``vortex singing.'' This research was funded by the Lloyd's Register Foundation as part of the International Institute for Cavitation Research.

Energy Saver: Tips on Saving Energy and Money in Your Home

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casey, Allison L

This guide shows you how easy it is to reduce your energy use at home and on the road. You'll find quick tips you can use to start saving today, as well as information on larger projects that will help save you money over the long term. Find even more information about saving money and energy at home by visiting our website, EnergySaver.gov.

Towards force spectroscopy of single tip-link bonds

NASA Astrophysics Data System (ADS)

Koussa, Mounir A.; Sotomayor, Marcos; Wong, Wesley P.; Corey, David P.

2015-12-01

Inner-ear mechanotransduction relies on tip links, fine protein filaments made of cadherin-23 and protocadherin-15 that convey tension to mechanosensitive channels at the tips of hair-cell stereocilia. The tip-link cadherins are thought to form a heterotetrameric complex, with two cadherin-23 molecules forming the upper part of the filament and two protocadherin-15 molecules forming the lower end. The interaction between cadherin-23 and protocadherin-15 is mediated by their N-terminal tips. Missense mutations that modify the interaction interface impair binding and lead to deafness. Molecular dynamics simulations predict that the tip-link bond is mechanically strong enough to withstand forces in hair cells, but its experimentally determined strength is unknown. We have developed molecular tools to facilitate single-molecule force spectroscopy on the tip link bond. Self-assembling DNA nanoswitches are functionalized with the interacting tips of cadherin-23 and protocadherin-15 using the enzyme sortase under conditions that preserve protein function. These tip link nanoswitches are designed to provide a signature force-extension profile. This molecular signature should allow us to identify single-molecule rupture events in pulling experiments.

The effect of substrate on electric field enhancement of Tip-enhanced Raman spectroscopy (TERS)

NASA Astrophysics Data System (ADS)

Bahreini, Maryam

2018-01-01

The characterization of materials down to a few-molecule level is a key challenge in nanotechnology. Raman spectroscopy is a powerful method that provides chemical information via nondestructive vibrational fingerprinting. Unfortunately, this method suffers from signal weakness which prevents the study of small quantities. Tip-enhanced Raman spectroscopy (TERS) which combines the chemical sensitivity of Raman spectroscopy (RS) with high spatial resolution of scanning probe microscopy (SPM), provides chemical images of surfaces at the nanometer scale. In this method, irradiation of an SPM tip by a focused laser beam results in enhancement of local electric field via two reasons of localized surface plasmon resonance and lightning rod effect. This enhancement leads to the enhancement in Raman intensity from the sample surface in the vicinity of tip. In all TERS measurements, samples should be located on a substrate. In this paper, the dependence of the electric field enhancement to the substrate has been investigated. In simulations, three-dimensional finite-difference time-domain (3D-FDTD) method is used for numerical solution of Maxwell's equations. Our results show that the electric field enhancement is weak for the tip alone case. Introducing a substrate provides further electric field enhancement via near field electromagnetic dipole-dipole coupling between the tip and substrate. Since the side-illumination geometry is used for laser irradiation, the vertical component of the incident field plays a dominant role in the electric field enhancement. Therefore, the coupling effect between the tip and the substrate is the key contribution to the enhancement. For the case of silicon tip and the gold substrate, the electric field enhancement is improved considerably. There is an optimal tip size for TERS because of the competing effects of the radiation damping and the surface scattering of the tip. The results show the substrate as an effective tool for the

Optical fiber meta-tips

NASA Astrophysics Data System (ADS)

Principe, Maria; Micco, Alberto; Crescitelli, Alessio; Castaldi, Giuseppe; Consales, Marco; Esposito, Emanuela; La Ferrara, Vera; Galdi, Vincenzo; Cusano, Andrea

2016-04-01

We report on the first example of a "meta-tip" configuration that integrates a metasurface on the tip of an optical fiber. Our proposed design is based on an inverted-Babinet plasmonic metasurface obtained by patterning (via focused ion beam) a thin gold film deposited on the tip of an optical fiber, so as to realize an array of rectangular aperture nanoantennas with spatially modulated sizes. By properly tuning the resonances of the aperture nanoantennas, abrupt variations can be impressed in the field wavefront and polarization. We fabricated and characterized several proof-of-principle prototypes operating an near-infrared wavelengths, and implementing the beam-steering (with various angles) of the cross-polarized component, as well as the excitation of surface waves. Our results pave the way to the integration of the exceptional field-manipulation capabilities enabled by metasurfaces with the versatility and ubiquity of fiber-optics technological platforms.

Lithotripsy Performance of Specially Designed Laser Fiber Tips.

PubMed

Kronenberg, Peter; Traxer, Olivier

2016-05-01

We evaluated and compared a standard laser lithotripsy fiber to laser fibers claimed to have lithotripsy performance enhancing features. A special AccuMax™ 200 polished tip fiber and an AccuTrac™ ball-shaped tip fiber, each with an approximately 240 μm core, were compared to a standard 272 μm core fiber (Rocamed™). The polished and ball-shaped tip fibers were used and reused without preparation. The standard fiber was stripped and cleaved according to manufacturer instructions after each experiment. An automated laser fragmentation testing system was used to perform multiple 30-second laser lithotripsy experiments. To mimic most typical lithotripsy conditions soft and hard stone materials were used with high frequency, low pulse energy (20 Hz and 0.5 J) or with low frequency, high pulse energy (5 Hz and 2.0 J) lithotripter settings. Ablation volumes and laser fiber tip photographs before and after lithotripsy were compared. The standard and ball-shaped tip fibers did not differ in ablation volume (p = 0.72) but they ablated 174% and 188% more stone, respectively, than the polished tip fiber (p <0.0001). The ball-shaped tip showed remarkable fiber tip degradation after short-term use at low frequency, high pulse energy settings. When high pulse energy settings were applied first even for short-term use, the ablation volume achieved by the polished and ball-shaped tip fibers at high frequency, low pulse energy settings decreased more than 20%. The standard laser fiber was as good as and sometimes better than the specially designed fibers. Rapid degradation of the specially designed laser fiber tips strongly limits their general usefulness but ball-shaped tip fibers may be useful in specific situations. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Local Mass and Heat Transfer on a Turbine Blade Tip

DOE PAGES

Jin, P.; Goldstein, R. J.

2003-01-01

Locmore » al mass and heat transfer measurements on a simulated high-pressure turbine blade-tip surface are conducted in a linear cascade with a nonmoving tip endwall, using a naphthalene sublimation technique. The effects of tip clearance (0.86–6.90% of chord) are investigated at various exit Reynolds numbers (4–7 × 10 5 ) and turbulence intensities (0.2 and 12.0%). The mass transfer on the tip surface is significant along its pressure edge at the smallest tip clearance. At the two largest tip clearances, the separation bubble on the tip surface can cover the whole width of the tip on the second half of the tip surface. The average mass-transfer rate is highest at a tip clearance of 1.72% of chord. The average mass-transfer rate on the tip surface is four and six times as high as on the suction and the pressure surface, respectively. A high mainstream turbulence level of 12.0% reduces average mass-transfer rates on the tip surface, while the higher mainstream Reynolds number generates higher local and average mass-transfer rates on the tip surface.« less

Note: Microelectrode-shielding tip for scanning probe electron energy spectroscopy

NASA Astrophysics Data System (ADS)

Huang, Wei; Li, Zhean; Xu, Chunkai; Liu, Jian; Xu, Chunye; Chen, Xiangjun

2018-04-01

We report a novel microelectrode-shielding tip (ME tip) for scanning probe electron energy spectroscopy (SPEES). The shielding effect of this tip is studied through comparing the detection efficiency with the normal tip by both experiment and simulation. The results show that the backscattering count rate detected by the SPEES instrument using the normal tip begins to decrease as the tip approaches to the sample surface within 21 μm, while that using the ME tip only starts to drop off within 1 μm. This indicates that the electron energy spectra can be measured with the ME tip at a much closer tip-sample distance. Furthermore, it is also demonstrated that the ME tip can be used to obtain topography of the sample surface in situ simultaneously.

7 CFR 29.3154 - Tips (T Group).

Code of Federal Regulations, 2011 CFR

2011-01-01

... stalk. (See Rule 12.) Grades Grade names and specifications T3F Good Tan Tips. Medium body, mature to...″ in length, 85 percent uniform, and 15 percent injury tolerance. T4F Fair Tan Tips. Medium body..., and 20 percent injury tolerance. T5F Low Tan Tips. Medium body, mature, firm, wrinkly, dingy finish...

7 CFR 29.3154 - Tips (T Group).

Code of Federal Regulations, 2010 CFR

2010-01-01

... stalk. (See Rule 12.) Grades Grade names and specifications T3F Good Tan Tips. Medium body, mature to...″ in length, 85 percent uniform, and 15 percent injury tolerance. T4F Fair Tan Tips. Medium body..., and 20 percent injury tolerance. T5F Low Tan Tips. Medium body, mature, firm, wrinkly, dingy finish...

Injector tip for an internal combustion engine

DOEpatents

Shyu, Tsu Pin; Ye, Wen

2003-05-20

This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

Turbine blade tip flow discouragers

DOEpatents

Bunker, Ronald Scott

2000-01-01

A turbine assembly comprises a plurality of rotating blade portions in a spaced relation with a stationery shroud. The rotating blade portions comprise a root section, a tip portion and an airfoil. The tip portion has a pressure side wall and a suction side wall. A number of flow discouragers are disposed on the blade tip portion. In one embodiment, the flow discouragers extend circumferentially from the pressure side wall to the suction side wall so as to be aligned generally parallel to the direction of rotation. In an alternative embodiment, the flow discouragers extend circumferentially from the pressure side wall to the suction side wall so as to be aligned at an angle in the range between about 0.degree. to about 60.degree. with respect to a reference axis aligned generally parallel to the direction of rotation. The flow discouragers increase the flow resistance and thus reduce the flow of hot gas flow leakage for a given pressure differential across the blade tip portion so as to improve overall turbine efficiency.

Effect of rotor tip clearance and configuration on overall performance of a 12.77-centimeter tip diameter axial-flow turbine

NASA Technical Reports Server (NTRS)

Haas, J. E.; Kofskey, M. G.

1978-01-01

The rotor tip clearance was obtained by use of a recess in the casing above the rotor blades and also by use of a reduced blade height. For the recessed casing configuration, the optimum rotor blade height was found to be the one where the rotor tip diameter was equal to the stator tip diameter. The tip clearance loss associated with this optimum recessed casing configuration was less than that for the reduced blade height configuration.

Illinois Early Learning Project Tip Sheets: Parenting and Family Life.

ERIC Educational Resources Information Center

2003

The Illinois Early Learning Project (IEL) is funded by the Illinois State Board of Education to provide information resources on early learning and training related to implementing the Illinois Early Learning Standards for parents and for early childhood personnel in all settings. The IEL tip sheets offer suggestions to parents and early childhood…

Illinois Early Learning Project Tip Sheets: Physical Development and Health.

ERIC Educational Resources Information Center

2003

The Illinois Early Learning Project (IEL) is funded by the Illinois State Board of Education to provide information resources on early learning and training related to implementing the Illinois Early Learning Standards for parents and for early childhood personnel in all settings. The IEL tip sheets offer suggestions to parents and early childhood…

Management of Bleeding Duodenal Varices with Combined TIPS Decompression and Trans-TIPS Transvenous Obliteration Utilizing 3% Sodium Tetradecyl Sulfate Foam Sclerosis.

PubMed

Saad, Wael E; Lippert, Allison; Schwaner, Sandra; Al-Osaimi, Abdullah; Sabri, Saher; Saad, Nael

2014-01-01

Endoscopic experience in the management of duodenal varices (DVs) is limited and challenging given the anatomic constraints and limited experience. The endovascular management of DVs is not yet established and the controversy of whether to manage them by decompression with a transjugular intrahepatic portosystemic shunt (TIPS) or by transvenous obliteration is unresolved. In the literature, the 6-12 month rebleeding rate of DVs after TIPS is 21-37% and after transvenous obliteration is 13%. The purpose of the study is to evaluate the clinical outcome of combined TIPS decompression and transvenous obliteration/sclerosis. This is a retrospective study (case series) of two institutions, evaluating patients who underwent TIPS and/or transvenous obliteration/sclerosis for bleeding DVs (from January 2009 to June 2013). TIPS was performed according to a standard procedure using covered stents. Transvenous obliteration (variceal sclerosis) from the systemic and/or portal venous circulation was performed utilizing 3% sodium tetradecyl sulfate foam. Transvenous obliteration was commonly augmented with coils and/or vascular plugs. Technical (technical success of establishing TIPS and completely obliterating the DVs) and clinical outcomes (rebleeding rate and survival) were evaluated. Five patients with liver cirrhosis presenting with bleeding DVs were included in the study with all eventually (and coincidentally) receiving TIPS and transvenous obliteration. Two of the five patients underwent concomitant TIPS and transvenous obliteration in the same procedural setting. However, three patients underwent transvenous obliteration due to bleeding despite a patent TIPS that had been previously placed. The average time from TIPS placement to transvenous obliteration was 125 days (range: 3-324 days). After having both procedures, there was no rebleeding in the patients during a mean follow-up period of 22 months (6-50 months). Coils and/or metallic vascular plugs were used to augment

Twelve tips for applying the science of learning to health professions education.

PubMed

Gooding, H C; Mann, K; Armstrong, E

2017-01-01

Findings from the science of learning have clear implications for those responsible for teaching and curricular design. However, this data has been historically siloed from educators in practice, including those in health professions education. In this article, we aim to bring practical tips from the science of learning to health professions educators. We have chosen to organize the tips into six themes, highlighting strategies for 1) improving the processing of information, 2) promoting effortful learning for greater retention of knowledge over time, 3) applying learned information to new and varied contexts, 4) promoting the development of expertise, 5) harnessing the power of emotion for learning, and 6) teaching and learning in social contexts. We conclude with the importance of attending to metacognition in our learners and ourselves. Health professions education can be strengthened by incorporating these evidence-based techniques.

Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures

PubMed Central

2012-01-01

Background One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating. Methods A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip. Results A maximum temperature rise of 22.4°C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2°C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8°C. Conclusion Up to a maximum of 22.4°C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip

Presenting practice financial information.

PubMed

Webster, Lee Ann H

2007-01-01

Medical practice leadership teams, often consisting primarily of physicians with limited financial backgrounds, must make important business decisions and continuously monitor practice operations. In order to competently perform this duty, they need financial reports that are relevant and easy to understand. This article explores financial reporting and decision-making in a physician practice. It discusses reports and tools, such as ratios, graphs, and comparisons, that practices typically include in their reports. Because profitability and cash flow are often the most important financial considerations for physician practices, reports should generally focus on the impact of various activities and potential decisions upon these concerns. This article also provides communication tips for both those presenting practice financial information and those making the decisions. By communicating effectively, these leaders can best use financial information to improve decision-making and maximize financial performance.

A neural mechanism for background information-gated learning based on axonal-dendritic overlaps.

PubMed

Mainetti, Matteo; Ascoli, Giorgio A

2015-03-01

Experiencing certain events triggers the acquisition of new memories. Although necessary, however, actual experience is not sufficient for memory formation. One-trial learning is also gated by knowledge of appropriate background information to make sense of the experienced occurrence. Strong neurobiological evidence suggests that long-term memory storage involves formation of new synapses. On the short time scale, this form of structural plasticity requires that the axon of the pre-synaptic neuron be physically proximal to the dendrite of the post-synaptic neuron. We surmise that such "axonal-dendritic overlap" (ADO) constitutes the neural correlate of background information-gated (BIG) learning. The hypothesis is based on a fundamental neuroanatomical constraint: an axon must pass close to the dendrites that are near other neurons it contacts. The topographic organization of the mammalian cortex ensures that nearby neurons encode related information. Using neural network simulations, we demonstrate that ADO is a suitable mechanism for BIG learning. We model knowledge as associations between terms, concepts or indivisible units of thought via directed graphs. The simplest instantiation encodes each concept by single neurons. Results are then generalized to cell assemblies. The proposed mechanism results in learning real associations better than spurious co-occurrences, providing definitive cognitive advantages.

A Neural Mechanism for Background Information-Gated Learning Based on Axonal-Dendritic Overlaps

PubMed Central

Mainetti, Matteo; Ascoli, Giorgio A.

2015-01-01

Experiencing certain events triggers the acquisition of new memories. Although necessary, however, actual experience is not sufficient for memory formation. One-trial learning is also gated by knowledge of appropriate background information to make sense of the experienced occurrence. Strong neurobiological evidence suggests that long-term memory storage involves formation of new synapses. On the short time scale, this form of structural plasticity requires that the axon of the pre-synaptic neuron be physically proximal to the dendrite of the post-synaptic neuron. We surmise that such “axonal-dendritic overlap” (ADO) constitutes the neural correlate of background information-gated (BIG) learning. The hypothesis is based on a fundamental neuroanatomical constraint: an axon must pass close to the dendrites that are near other neurons it contacts. The topographic organization of the mammalian cortex ensures that nearby neurons encode related information. Using neural network simulations, we demonstrate that ADO is a suitable mechanism for BIG learning. We model knowledge as associations between terms, concepts or indivisible units of thought via directed graphs. The simplest instantiation encodes each concept by single neurons. Results are then generalized to cell assemblies. The proposed mechanism results in learning real associations better than spurious co-occurrences, providing definitive cognitive advantages. PMID:25767887

Hard-tip, soft-spring lithography.

PubMed

Shim, Wooyoung; Braunschweig, Adam B; Liao, Xing; Chai, Jinan; Lim, Jong Kuk; Zheng, Gengfeng; Mirkin, Chad A

2011-01-27

Nanofabrication strategies are becoming increasingly expensive and equipment-intensive, and consequently less accessible to researchers. As an alternative, scanning probe lithography has become a popular means of preparing nanoscale structures, in part owing to its relatively low cost and high resolution, and a registration accuracy that exceeds most existing technologies. However, increasing the throughput of cantilever-based scanning probe systems while maintaining their resolution and registration advantages has from the outset been a significant challenge. Even with impressive recent advances in cantilever array design, such arrays tend to be highly specialized for a given application, expensive, and often difficult to implement. It is therefore difficult to imagine commercially viable production methods based on scanning probe systems that rely on conventional cantilevers. Here we describe a low-cost and scalable cantilever-free tip-based nanopatterning method that uses an array of hard silicon tips mounted onto an elastomeric backing. This method-which we term hard-tip, soft-spring lithography-overcomes the throughput problems of cantilever-based scanning probe systems and the resolution limits imposed by the use of elastomeric stamps and tips: it is capable of delivering materials or energy to a surface to create arbitrary patterns of features with sub-50-nm resolution over centimetre-scale areas. We argue that hard-tip, soft-spring lithography is a versatile nanolithography strategy that should be widely adopted by academic and industrial researchers for rapid prototyping applications.

Investigation on tip enhanced Raman spectra of graphene

NASA Astrophysics Data System (ADS)

Li, Xinjuan; Liu, Yanqi; Zeng, Zhuo; Wang, Peijie; Fang, Yan; Zhang, Lisheng

2018-02-01

Tip-enhanced Raman scattering (TERS) is a promising analytical approach for some two-dimensional materials and offers the possibility to correlate imaging and chemical data. Tip-enhanced Raman spectra of graphene are discussed in some details, including substrate, gap between tip-apex and sample surface as well as Ag-nanowire. The TERS spectra give special emphasis to the possibility of TERS tip to induce a large number of defects only while got the tip attached to sample surface. Then the dependence of the TERS spectra of graphene and gap between the probe tip and sample surface was studied, and distribution features of electromagnetic (EM) field around tip were also simulated by finite-difference time-domain (FDTD). The Raman signal enhancement of graphene was further discussed with respect to experimental data. Furthermore, the Ag-nanowire as a nano-antenna could significantly enhance the weak Raman signal of D-band of monolayer graphene is shown, and the TERS spectra of graphene with regard to different regions of Ag-nanowires (endpoints, body) were obtained toward investigating into the distribution of electromagnetic field.

Advanced optical blade tip clearance measurement system

NASA Technical Reports Server (NTRS)

Ford, M. J.; Honeycutt, R. E.; Nordlund, R. E.; Robinson, W. W.

1978-01-01

An advanced electro-optical system was developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in an operating gas turbine engine. This system is applicable to fan, compressor, and turbine blade tip clearance measurement requirements, and the system probe is particularly suitable for operation in the extreme turbine environment. A study of optical properties of blade tips was conducted to establish measurement system application limitations. A series of laboratory tests was conducted to determine the measurement system's operational performance characteristics and to demonstrate system capability under simulated operating gas turbine environmental conditions. Operational and environmental performance test data are presented.

Reappraising Abstract Paintings after Exposure to Background Information

PubMed Central

Park, Seongmin A.; Yun, Kyongsik; Jeong, Jaeseung

2015-01-01

Can knowledge help viewers when they appreciate an artwork? Experts’ judgments of the aesthetic value of a painting often differ from the estimates of naïve viewers, and this phenomenon is especially pronounced in the aesthetic judgment of abstract paintings. We compared the changes in aesthetic judgments of naïve viewers while they were progressively exposed to five pieces of background information. The participants were asked to report their aesthetic judgments of a given painting after each piece of information was presented. We found that commentaries by the artist and a critic significantly increased the subjective aesthetic ratings. Does knowledge enable experts to attend to the visual features in a painting and to link it to the evaluative conventions, thus potentially causing different aesthetic judgments? To investigate whether a specific pattern of attention is essential for the knowledge-based appreciation, we tracked the eye movements of subjects while viewing a painting with a commentary by the artist and with a commentary by a critic. We observed that critics’ commentaries directed the viewers’ attention to the visual components that were highly relevant to the presented commentary. However, attention to specific features of a painting was not necessary for increasing the subjective aesthetic judgment when the artists’ commentary was presented. Our results suggest that at least two different cognitive mechanisms may be involved in knowledge- guided aesthetic judgments while viewers reappraise a painting. PMID:25945789

Technology Tips

ERIC Educational Resources Information Center

Santos-Trigo, Manuel

2004-01-01

A dynamic program for geometry called Cabri Geometry II is used to examine properties of figures like triangles and make connections with other mathematical ideas like ellipse. The technology tip includes directions for creating such a problem with technology and suggestions for exploring it.

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

PubMed Central

Jarvis, Sam; Danza, Rosanna; Moriarty, Philip

2012-01-01

Summary Background: Noncontact atomic force microscopy (NC-AFM) now regularly produces atomic-resolution images on a wide range of surfaces, and has demonstrated the capability for atomic manipulation solely using chemical forces. Nonetheless, the role of the tip apex in both imaging and manipulation remains poorly understood and is an active area of research both experimentally and theoretically. Recent work employing specially functionalised tips has provided additional impetus to elucidating the role of the tip apex in the observed contrast. Results: We present an analysis of the influence of the tip apex during imaging of the Si(100) substrate in ultra-high vacuum (UHV) at 5 K using a qPlus sensor for noncontact atomic force microscopy (NC-AFM). Data demonstrating stable imaging with a range of tip apexes, each with a characteristic imaging signature, have been acquired. By imaging at close to zero applied bias we eliminate the influence of tunnel current on the force between tip and surface, and also the tunnel-current-induced excitation of silicon dimers, which is a key issue in scanning probe studies of Si(100). Conclusion: A wide range of novel imaging mechanisms are demonstrated on the Si(100) surface, which can only be explained by variations in the precise structural configuration at the apex of the tip. Such images provide a valuable resource for theoreticians working on the development of realistic tip structures for NC-AFM simulations. Force spectroscopy measurements show that the tip termination critically affects both the short-range force and dissipated energy. PMID:22428093

Quasi-linearly polarized hybrid modes in tapered and metal-coated tips with circular apertures: understanding the functionality of aperture tips

NASA Astrophysics Data System (ADS)

Tugchin, B. N.; Janunts, N.; Steinert, M.; Dietrich, K.; Kley, E. B.; Tünnermann, A.; Pertsch, T.

2017-06-01

In this study, we investigate analytically and experimentally the roles of quasi-linearly polarized (LP), hybrid, plasmonic and photonic modes in optical detection and excitation with aperture tips in scanning near-field optical microscopy. Aperture tips are tapered and metal-coated optical fibers where small circular apertures are made at the apex. In aperture tips, there exist plasmonic modes that are bound at the interface of the metal cladding to the inner dielectric fiber and photonic modes that are guided in the area of the increased index in the dielectric fiber core. The fundamental photonic mode, although excited by the free-space Gaussian beam, experiences cutoff and turns into an evanescent mode. The photonic mode also becomes lossier than the plasmonic mode toward the tip aperture, and its power decay due to absorption and reflection is expected to be at least 10-9. In contrast, the fundamental plasmonic mode has no cutoff and thus reaches all the way to the tip aperture. Due to the non-adiabaticity of both modes’ propagations through the taper below a core radius of 600 nm, there occurs coupling between the modes. The transmission efficiency of the plasmonic mode, including the coupling efficiency and the propagation loss, is expected to be about 10-6 that is at least 3 orders of magnitude larger than that of the photonic mode. Toward the tip aperture, the longitudinal field of the photonic mode becomes stronger than the transverse ones while the transverse fields always dominate for the plasmonic mode. Experimentally, we obtain polarization resolved images of the near-field at the tip aperture and compare with the x- and y-components of the fundamental quasi-LP plasmonic and photonic modes. The results show that not only the pattern but also the intensity ratios of the x- and y-components of the aperture near-field match with that of the fundamental plasmonic mode. Consequently, we conclude that only the plasmonic mode reaches the tip aperture and

Local X-ray magnetic circular dichroism study of Fe/Cu(111) using a tunneling smart tip

PubMed Central

DiLullo, Andrew; Shirato, Nozomi; Cummings, Marvin; Kersell, Heath; Chang, Hao; Rosenmann, Daniel; Miller, Dean; Freeland, John W.; Hla, Saw-Wai; Rose, Volker

2016-01-01

Localized spectroscopy with simultaneous topographic, elemental and magnetic information is presented. A synchrotron X-ray scanning tunneling microscope has been employed for the local study of the X-ray magnetic circular dichroism at the Fe L 2,3-edges of a thin iron film grown on Cu(111). Polarization-dependent X-ray absorption spectra have been obtained through a tunneling smart tip that serves as a photoelectron detector. In contrast to conventional spin-polarized scanning tunneling microscopy, X-ray excitations provide magnetic contrast even with a non-magnetic tip. Intensity variations in the photoexcited tip current point to chemical variations within a single magnetic Fe domain. PMID:26917146

Local X-ray magnetic circular dichroism study of Fe/Cu(111) using a tunneling smart tip

DOE PAGES

DiLullo, Andrew; Shirato, Nozomi; Cummings, Marvin; ...

2016-01-28

Localized spectroscopy with simultaneous topographic, elemental and magnetic information is presented. A synchrotron X-ray scanning tunneling microscope has been employed for the local study of the X-ray magnetic circular dichroism at the FeL 2,3-edges of a thin iron film grown on Cu(111). Polarization-dependent X-ray absorption spectra have been obtained through a tunneling smart tip that serves as a photoelectron detector. In contrast to conventional spin-polarized scanning tunneling microscopy, X-ray excitations provide magnetic contrast even with a non-magnetic tip. Intensity variations in the photoexcited tip current point to chemical variations within a single magnetic Fe domain.

Local X-ray magnetic circular dichroism study of Fe/Cu(111) using a tunneling smart tip.

PubMed

DiLullo, Andrew; Shirato, Nozomi; Cummings, Marvin; Kersell, Heath; Chang, Hao; Rosenmann, Daniel; Miller, Dean; Freeland, John W; Hla, Saw-Wai; Rose, Volker

2016-03-01

Localized spectroscopy with simultaneous topographic, elemental and magnetic information is presented. A synchrotron X-ray scanning tunneling microscope has been employed for the local study of the X-ray magnetic circular dichroism at the Fe L2,3-edges of a thin iron film grown on Cu(111). Polarization-dependent X-ray absorption spectra have been obtained through a tunneling smart tip that serves as a photoelectron detector. In contrast to conventional spin-polarized scanning tunneling microscopy, X-ray excitations provide magnetic contrast even with a non-magnetic tip. Intensity variations in the photoexcited tip current point to chemical variations within a single magnetic Fe domain.

TIPS Evaluation Project Retrospective Study: Wave 1 and 2.

ERIC Educational Resources Information Center

Hubbard, Susan M.; Mulvey, Kevin P.

2003-01-01

Measured substance abuse treatment professionals' knowledge, attitudes, and practices regarding the Treatment Improvement Protocol (TIP) series and the 28 TIPs. Results for 3,267 respondents in wave 1 and 1,028 in wave 2 indicate that almost half of all professionals were aware of the TIPs. Attitudes toward TIPs were positive, but professionals…

Advanced ceramic material for high temperature turbine tip seals

NASA Technical Reports Server (NTRS)

Vogan, J. W.; Solomon, N. G.; Stetson, A. R.

1980-01-01

Forty-one material systems were evaluated for potential use in turbine blade tip seal applications at 1370 C. Both ceramic blade tip inserts and abradable ceramic tip shoes were tested. Hot gas erosion, impact resistance, thermal stability, and dynamic rub performance were the criteria used in rating the various materials. Silicon carbide and silicon nitride were used, both as blade tips and abradables. The blade tip inserts were fabricated by hot pressing while low density and honeycomb abradables were sintered or reaction bonded.

Needle tip localization using stylet vibration.

PubMed

Harmat, Adam; Rohling, Robert N; Salcudean, Septimiu E

2006-09-01

Power Doppler ultrasound is used to localize the tip of a needle by detecting physical vibrations. Two types of vibrations are investigated, lateral and axial. The lateral vibrations are created by rotating a stylet, whose tip is slightly bent, inside a stationary cannula while the stylet is completely within the cannula. The minute deflection at the needle tip when rotated causes tissue motion. The axial vibration is induced by extending and retracting a straight stylet inside a stationary cannula. The stylet's tip makes contact with the tissue and causes it to move. The lateral vibration method was found to perform approximately the same under a variety of configurations (e.g., different insertion angles and depths) and better than the axial vibration method. Tissue stiffness affects the performance of the lateral vibration method, but good images can be obtained through proper tuning of the ultrasound machine.

Talking to Your Kids about Sex: Tips for Tongue-Tied Parents.

ERIC Educational Resources Information Center

PTA Today, 1993

1993-01-01

Tips to help parents discuss sex with their children include starting early, providing enough information, planning what to say, listening to the children, finding opportunities to discuss sexual roles and attitudes, discussing family values, nurturing self-esteem, avoiding lectures, using written materials as ice-breakers, and starting a family…

Management of Bleeding Duodenal Varices with Combined TIPS Decompression and Trans-TIPS Transvenous Obliteration Utilizing 3% Sodium Tetradecyl Sulfate Foam Sclerosis

PubMed Central

Saad, Wael E; Lippert, Allison; Schwaner, Sandra; Al-Osaimi, Abdullah; Sabri, Saher; Saad, Nael

2014-01-01

Objectives: Endoscopic experience in the management of duodenal varices (DVs) is limited and challenging given the anatomic constraints and limited experience. The endovascular management of DVs is not yet established and the controversy of whether to manage them by decompression with a transjugular intrahepatic portosystemic shunt (TIPS) or by transvenous obliteration is unresolved. In the literature, the 6–12 month rebleeding rate of DVs after TIPS is 21-37% and after transvenous obliteration is 13%. The purpose of the study is to evaluate the clinical outcome of combined TIPS decompression and transvenous obliteration/sclerosis. Materials and Methods: This is a retrospective study (case series) of two institutions, evaluating patients who underwent TIPS and/or transvenous obliteration/sclerosis for bleeding DVs (from January 2009 to June 2013). TIPS was performed according to a standard procedure using covered stents. Transvenous obliteration (variceal sclerosis) from the systemic and/or portal venous circulation was performed utilizing 3% sodium tetradecyl sulfate foam. Transvenous obliteration was commonly augmented with coils and/or vascular plugs. Technical (technical success of establishing TIPS and completely obliterating the DVs) and clinical outcomes (rebleeding rate and survival) were evaluated. Results: Five patients with liver cirrhosis presenting with bleeding DVs were included in the study with all eventually (and coincidentally) receiving TIPS and transvenous obliteration. Two of the five patients underwent concomitant TIPS and transvenous obliteration in the same procedural setting. However, three patients underwent transvenous obliteration due to bleeding despite a patent TIPS that had been previously placed. The average time from TIPS placement to transvenous obliteration was 125 days (range: 3-324 days). After having both procedures, there was no rebleeding in the patients during a mean follow-up period of 22 months (6–50 months). Coils and

Extended Glauert tip correction to include vortex rollup effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maniaci, David; Schmitz, Sven

Wind turbine loads predictions by blade-element momentum theory using the standard tip-loss correction have been shown to over-predict loading near the blade tip in comparison to experimental data. This over-prediction is theorized to be due to the assumption of light rotor loading, inherent in the standard tip-loss correction model of Glauert. A higher- order free-wake method, WindDVE, is used to compute the rollup process of the trailing vortex sheets downstream of wind turbine blades. Results obtained serve an exact correction function to the Glauert tip correction used in blade-element momentum methods. Lastly, it is found that accounting for the effectsmore » of tip vortex rollup within the Glauert tip correction indeed results in improved prediction of blade tip loads computed by blade-element momentum methods.« less

Extended Glauert tip correction to include vortex rollup effects

DOE PAGES

Maniaci, David; Schmitz, Sven

2016-10-03

Wind turbine loads predictions by blade-element momentum theory using the standard tip-loss correction have been shown to over-predict loading near the blade tip in comparison to experimental data. This over-prediction is theorized to be due to the assumption of light rotor loading, inherent in the standard tip-loss correction model of Glauert. A higher- order free-wake method, WindDVE, is used to compute the rollup process of the trailing vortex sheets downstream of wind turbine blades. Results obtained serve an exact correction function to the Glauert tip correction used in blade-element momentum methods. Lastly, it is found that accounting for the effectsmore » of tip vortex rollup within the Glauert tip correction indeed results in improved prediction of blade tip loads computed by blade-element momentum methods.« less

Tip-tilt disturbance model identification based on non-linear least squares fitting for Linear Quadratic Gaussian control

NASA Astrophysics Data System (ADS)

Yang, Kangjian; Yang, Ping; Wang, Shuai; Dong, Lizhi; Xu, Bing

2018-05-01

We propose a method to identify tip-tilt disturbance model for Linear Quadratic Gaussian control. This identification method based on Levenberg-Marquardt method conducts with a little prior information and no auxiliary system and it is convenient to identify the tip-tilt disturbance model on-line for real-time control. This identification method makes it easy that Linear Quadratic Gaussian control runs efficiently in different adaptive optics systems for vibration mitigation. The validity of the Linear Quadratic Gaussian control associated with this tip-tilt disturbance model identification method is verified by experimental data, which is conducted in replay mode by simulation.

Fabrication of a trimer/single atom tip for gas field ion sources by means of field evaporation without tip heating.

PubMed

Kim, Kwang-Il; Kim, Young Heon; Ogawa, Takashi; Choi, Suji; Cho, Boklae; Ahn, Sang Jung; Park, In-Yong

2018-05-11

A gas field ion source (GFIS) has many advantages that are suitable for ion microscope sources, such as high brightness and a small virtual source size, among others. In order to apply a tip-based GFIS to an ion microscope, it is better to create a trimer/single atom tip (TSAT), where the ion beam must be generated in several atoms of the tip apex. Here, unlike the conventional method which uses tip heating or a reactive gas, we show that the tip surface can be cleaned using only the field evaporation phenomenon and that the TSAT can also be fabricated using an insulating layer containing tungsten oxide, which remains after electrochemical etching. Using this method, we could get TSAT over 90% of yield. Copyright © 2018. Published by Elsevier B.V.

E-Mail Writing: Providing Background Information in the Core of Computer Assisted Instruction

ERIC Educational Resources Information Center

Nazari, Behzad; Ninknejad, Sahar

2015-01-01

The present study highly supported the effective role of providing background information via email by the teacher to write e-mail by the students in learners' writing ability. A total number of 50 EFL advanced male students aged between 25 and 40 at different branches of Iran Language Institute in Tehran, Tehran. Through the placement test of…

Electrohydrodynamic and flow induced tip-streaming

NASA Astrophysics Data System (ADS)

Collins, Robert

2008-11-01

A liquid subjected to a strong electric field emits thin fluid jets from conical structures (Taylor cones) that form at its surface. Such behavior has both practical and fundamental implications, e.g. for raindrops in thunderclouds and in electrospray mass spectrometry. Theoretical analysis of the temporal development of such electrohydrodynamic (EHD) tip- streaming phenomena has been elusive given the large disparity in length scales between the macroscopic drops/films and the microscopic (nanoscopic) jets. Here, simulation and experiment are used to investigate the mechanisms of EHD tip-streaming from a film of finite conductivity. In the simulations, the full Taylor-Melcher leaky-dielectric model, which accounts for charge relaxation, is solved. Simulations show that tip- streaming does not occur for perfectly conducting or perfectly insulating liquids. Scaling laws for sizes of drops produced from the breakup of the thin jets is developed. Further, simulations demonstrate the critical role played by electrically induced surface shear stresses in the inception of tip-streaming. This invites a comparison to flow focusing, i.e. tip-streaming induced by co-flowing two fluids. The latter phenomenon is also investigated by simulation. In collaboration with Ronald Suryo, Exxon-Mobil; and Jeremy Jones, Michael Harris, and Osman Basaran, Purdue University.

Fabrication and characterization of CNT-based smart tips for synchrotron assisted STM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Hui; Cummings, Marvin; Camino, Fernando

Determination of chemical composition along with imaging at the atomic level provides critical information towards fundamental understanding of the surface of materials and, hence, yields the capability to design new materials by tailoring their ultimate functionalities. Synchrotron X-ray assisted scanning tunneling microscopy (SX-STM) is a promising new technique to achieve real space chemically specific atomic mapping. Chemical sensitivity of SX-STM relies on excitation of core electrons by incident X-rays when their energy is tuned to an absorption edge of a particular element. However, along with core-level electrons, photoelectrons are also excited, which yield additional current and interfere with the tunnelingmore » current. To reduce the background photoelectron current and to improve ultimate resolution of SX-STM, we have developed and fabricated multiwalled carbon nanotubes (MWCNT) based “smart tips” using plasma enhanced chemical vapor deposition and focused ion beam milling. As a result, the newly developed CNT-based smart tips, characterized step by step by scanning electron microscopy (SEM) during the fabrication process, demonstrate good performance and provide opportunity for realizing atomic chemical mapping.« less

Fabrication and characterization of CNT-based smart tips for synchrotron assisted STM

DOE PAGES

Yan, Hui; Cummings, Marvin; Camino, Fernando; ...

2015-08-05

Determination of chemical composition along with imaging at the atomic level provides critical information towards fundamental understanding of the surface of materials and, hence, yields the capability to design new materials by tailoring their ultimate functionalities. Synchrotron X-ray assisted scanning tunneling microscopy (SX-STM) is a promising new technique to achieve real space chemically specific atomic mapping. Chemical sensitivity of SX-STM relies on excitation of core electrons by incident X-rays when their energy is tuned to an absorption edge of a particular element. However, along with core-level electrons, photoelectrons are also excited, which yield additional current and interfere with the tunnelingmore » current. To reduce the background photoelectron current and to improve ultimate resolution of SX-STM, we have developed and fabricated multiwalled carbon nanotubes (MWCNT) based “smart tips” using plasma enhanced chemical vapor deposition and focused ion beam milling. As a result, the newly developed CNT-based smart tips, characterized step by step by scanning electron microscopy (SEM) during the fabrication process, demonstrate good performance and provide opportunity for realizing atomic chemical mapping.« less

Transonic rotor tip design using numerical optimization

NASA Technical Reports Server (NTRS)

Tauber, Michael E.; Langhi, Ronald G.

1985-01-01

The aerodynamic design procedure for a new blade tip suitable for operation at transonic speeds is illustrated. For the first time, 3 dimensional numerical optimization was applied to rotor tip design, using the recent derivative of the ROT22 code, program R22OPT. Program R22OPT utilized an efficient quasi-Newton optimization algorithm. Multiple design objectives were specified. The delocalization of the shock wave was to be eliminated in forward flight for an advance ratio of 0.41 and a tip Mach number of 0.92 at psi = 90 deg. Simultaneously, it was sought to reduce torque requirements while maintaining effective restoring pitching moments. Only the outer 10 percent of the blade span was modified; the blade area was not to be reduced by more than 3 percent. The goal was to combine the advantages of both sweptback and sweptforward blade tips. A planform that featured inboard sweepback was combined with a sweptforward tip and a taper ratio of 0.5. Initially, the ROT22 code was used to find by trial and error a planform geometry which met the design goals. This configuration had an inboard section with a leading edge sweep of 20 deg and a tip section swept forward at 25 deg; in addition, the airfoils were modified.

Magnetic elements for switching magnetization magnetic force microscopy tips.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cambel, V.; Elias, P.; Gregusova, D.

2010-09-01

Using combination of micromagnetic calculations and magnetic force microscopy (MFM) imaging we find optimal parameters for novel magnetic tips suitable for switching magnetization MFM. Switching magnetization MFM is based on two-pass scanning atomic force microscopy with reversed tip magnetization between the scans. Within the technique the sum of the scanned data with reversed tip magnetization depicts local atomic forces, while their difference maps the local magnetic forces. Here we propose the design and calculate the magnetic properties of tips suitable for this scanning probe technique. We find that for best performance the spin-polarized tips must exhibit low magnetic moment, lowmore » switching fields, and single-domain state at remanence. The switching field of such tips is calculated and optimum shape of the Permalloy elements for the tips is found. We show excellent correspondence between calculated and experimental results for Py elements.« less

News: Tripping over tipping points/elements

EPA Science Inventory

The term “tipping point” has been used to identify a critical threshold susceptible to a tiny perturbation that can qualitatively alter the state or development of a system. “Tipping element” has been introduced to describe large-scale components of the Earth system that may pass...

Twelve Tips for Effective Electronic Presentation.

ERIC Educational Resources Information Center

Crosby, Joy

1994-01-01

Offers 12 tips for effective electronic presentation. This article is intended for readers who may be considering using electronic presentation for the first time. Offers reasons for its popularity and occasions when it may be used. The tips offer assistance in the design and presentation of electronic material. (LZ)

Fall TIPS: strategies to promote adoption and use of a fall prevention toolkit.

PubMed

Dykes, Patricia C; Carroll, Diane L; Hurley, Ann; Gersh-Zaremski, Ronna; Kennedy, Ann; Kurowski, Jan; Tierney, Kim; Benoit, Angela; Chang, Frank; Lipsitz, Stuart; Pang, Justine; Tsurkova, Ruslana; Zuyov, Lyubov; Middleton, Blackford

2009-11-14

Patient falls are serious problems in hospitals. Risk factors for falls are well understood and nurses routinely assess for fall risk on all hospitalized patients. However, the link from nursing assessment of fall risk, to identification and communication of tailored interventions to prevent falls is yet to be established. The Fall TIPS (Tailoring Interventions for Patient Safety) Toolkit was developed to leverage existing practices and workflows and to employ information technology to improve fall prevention practices. The purpose of this paper is to describe the Fall TIPS Toolkit and to report on strategies used to drive adoption of the Toolkit in four acute care hospitals. Using the IHI "Framework for Spread" as a conceptual model, the research team describes the "spread" of the Fall TIPS Toolkit as means to integrate effective fall prevention practices into the workflow of interdisciplinary caregivers, patients and family members.

Bed Bug Tips

EPA Pesticide Factsheets

How to deal with bed bugs in one printable page. Ten tips include ensuring correct insect identification, reducing clutter, understand integrated pest management, using mattress and box spring encasements, and heat treatment.

Low Vision Tips

MedlinePlus

... this page: https://medlineplus.gov/lowvision.html MedlinePlus: Low Vision Tips We are sorry. MedlinePlus no longer maintains the For Low Vision Users page. You will still find health resources ...

Fiber-optic laser Doppler turbine tip clearance probe

NASA Astrophysics Data System (ADS)

Büttner, Lars; Pfister, Thorsten; Czarske, Jürgen

2006-05-01

A laser Doppler based method for in situ single blade tip clearance measurements of turbomachines with high precision is presented for what we believe is the first time. The sensor is based on two superposed fanlike interference fringe systems generated by two laser wavelengths from a fiber-coupled, passive, and therefore compact measurement head employing diffractive optics. Tip clearance measurements at a transonic centrifugal compressor performed during operation at 50,000 rpm (833 Hz, 586 m/s tip speed) are reported. At these speeds the measured uncertainty of the tip position was less than 20 μm, a factor of 2 more accurate than that of capacitive probes. The sensor offers great potential for in situ and online high-precision tip clearance measurements of metallic and nonmetallic turbine blades.

Fiber-optic laser Doppler turbine tip clearance probe.

PubMed

Büttner, Lars; Pfister, Thorsten; Czarske, Jürgen

2006-05-01

A laser Doppler based method for in situ single blade tip clearance measurements of turbomachines with high precision is presented for what we believe is the first time. The sensor is based on two superposed fanlike interference fringe systems generated by two laser wavelengths from a fiber-coupled, passive, and therefore compact measurement head employing diffractive optics. Tip clearance measurements at a transonic centrifugal compressor performed during operation at 50,000 rpm (833 Hz, 586 m/s tip speed) are reported. At these speeds the measured uncertainty of the tip position was less than 20 microm, a factor of 2 more accurate than that of capacitive probes. The sensor offers great potential for in situ and online high-precision tip clearance measurements of metallic and nonmetallic turbine blades.

Time-of-Flight Tip-Clearance Measurements

NASA Technical Reports Server (NTRS)

Dhadwal, H. S.; Kurkov, A. P.; Janetzke, D. C.

1999-01-01

In this paper a time-of-flight probe system incorporating the two integrated fiber optic probes which are tilted equally relative to the probe holder centerline, is applied for the first time to measure the tip clearance of an advanced fan prototype. Tip clearance is largely independent of the signal amplitude and it relies on timing measurement. This work exposes optical effects associated with the fan blade stagger angle that were absent during the original spin-rig experiment on the zero stagger rotor. Individual blade tip clearances were measured with accuracy of +/- 127-mm (+/- 0.005-in). Probe features are discussed and improvements to the design are suggested.

Tips for Reducing Pesticide Impacts on Wildlife

EPA Pesticide Factsheets

This Web page provides tips for pesticide users in residential and agricultural settings, as well as tips for certified pesticide applicators for ways to protect wildlife from potentially harmful effects of pesticides.

Ten Fire Safety Tips for Schools.

ERIC Educational Resources Information Center

Lake, James D.

1999-01-01

Provides 10 basic tips, compiled from the National Fire Protection Association's Life Safety Code 101, to ensure that educational facilities are fire safe. Tips include use of frequent and unexpected fire drills, limiting wall space of student artwork and teaching materials, being alert to preventing arson, planning speedy and safe emergency…

The influence of tip shape on bending force during needle insertion

PubMed Central

van de Berg, Nick J.; de Jong, Tonke L.; van Gerwen, Dennis J.; Dankelman, Jenny; van den Dobbelsteen, John J.

2017-01-01

Steering of needles involves the planning and timely modifying of instrument-tissue force interactions to allow for controlled deflections during the insertion in tissue. In this work, the effect of tip shape on these forces was studied using 10 mm diameter needle tips. Six different tips were selected, including beveled and conical versions, with or without pre-bend or pre-curve. A six-degree-of-freedom force/torque sensor measured the loads during indentations in tissue simulants. The increased insertion (axial) and bending (radial) forces with insertion depth — the force-displacement slopes — were analyzed. Results showed that the ratio between radial and axial forces was not always proportional. This means that the tip load does not have a constant orientation, as is often assumed in mechanics-based steering models. For all tip types, the tip-load assumed a more radial orientation with increased axial load. This effect was larger for straight tips than for pre-bent or pre-curved tips. In addition, the force-displacement slopes were consistently higher for (1) increased tip angles, and for (2) beveled tips compared to conical tips. Needles with a bent or curved tip allow for an increased bending force and a decreased variability of the tip load vector orientation. PMID:28074939

Nasal tip support: A finite element analysis of the role of the caudal septum during tip depression

PubMed Central

Manuel, Cyrus T.; Leary, Ryan; Protsenko, Dmitriy E.; Wong, Brian J.F.

2014-01-01

Objective/Hypothesis Although minor and major tip support mechanisms have been described in detail, no quantitative models exist to provide support for the relative contributions of the structural properties of the major alar cartilage, the fibrous attachments to surrounding structures, and the rigid support structures in an objective manner. Study Design The finite element method was used to compute the stress distribution in the nose during simple tip compression, and then identify the specific anatomic structures that resist deformation and thus contribute to “tip support”. Additionally, the impact of caudal septal resection on nasal tip support was examined. Method The computer models consisted of three tissue components with anatomically correct geometries for skin and bone derived from CT data. Septum, upper lateral cartilages, and major alar cartilages were fitted within the model using 3D CAD software. 5mm nasal tip compression was performed on the models with caudal septal resection (3mm and 5 mm) and without resection to simulate palpation, then the resulting spatial distribution of stress and displacement was calculated. Results The von Mises stress in the normal model was primarily concentrated along medial crural angle. As caudal septum length was reduced, stress was redistributed to adjacent soft tissue and bone, resulting in less force acting on the septum. In all models, displacement was greatest near the intermediate crura. Conclusions These models are the first step in the comprehensive mechanical analysis of nasal tip dynamics. Our model supports the concept of the caudal septum and major alar cartilage as providing the majority of critical load-bearing support. Level of Evidence N/A PMID:23878007

Invited Review Article: Tip modification methods for tip-enhanced Raman spectroscopy (TERS) and colloidal probe technique: A 10 year update (2006-2016) review

NASA Astrophysics Data System (ADS)

Yuan, C. C.; Zhang, D.; Gan, Y.

2017-03-01

Engineering atomic force microscopy tips for reliable tip enhanced Raman spectroscopy (TERS) and colloidal probe technique are becoming routine practices in many labs. In this 10 year update review, various new tip modification methods developed over the past decade are briefly reviewed to help researchers select the appropriate method. The perspective is put in a large context to discuss the opportunities and challenges in this area, including novel combinations of seemingly different methods, potential applications of some methods which were not originally intended for TERS tip fabrication, and the problems of high cost and poor reproducibility of tip fabrication.

Propeller noise caused by blade tip radial forces

NASA Technical Reports Server (NTRS)

Hanson, D. B.

1986-01-01

New experimental evidence which indicates the presence of leading edge and tip edge vortex flow on Prop-Fans is examined, and performance and noise consequences are addressed. It was shown that the tip edge vortex is a significant noise source, particularly for unswept Prop-Fan blades. Preliminary calculations revealed that the addition of the tip side edge source to single rotation Prop-Fans during take off conditions improved the agreement between experiment and theory at blade passing frequency. At high-speed conditions such as the Prop-Fan cruise point, the tip loading effect tends to cancel thickness noise.

Characterization of the interaction between AFM tips and surface nanobubbles.

PubMed

Walczyk, Wiktoria; Schönherr, Holger

2014-06-24

While the presence of gaseous enclosures observed at various solid-water interfaces, the so-called "surface nanobubles", has been confirmed by many groups in recent years, their formation, properties, and stability have not been convincingly and exhaustively explained. Here we report on an atomic force microscopy (AFM) study of argon nanobubbles on highly oriented pyrolitic graphite (HOPG) in water to elucidate the properties of nanobubble surfaces and the mechanism of AFM tip-nanobubble interaction. In particular, the deformation of the nanobubble-water interface by the AFM tip and the question whether the AFM tip penetrates the nanobubble during scanning were addressed by this combined intermittent contact (tapping) mode and force volume AFM study. We found that the stiffness of nanobubbles was smaller than the cantilever spring constant and comparable with the surface tension of water. The interaction with the AFM tip resulted in severe quasi-linear deformation of the bubbles; however, in the case of tip-bubble attraction, the interface deformed toward the tip. We tested two models of tip-bubble interaction, namely, the capillary force and the dynamic interaction model, and found, depending on the tip properties, good agreement with experimental data. The results showed that the tip-bubble interaction strength and the magnitude of the bubble deformation depend strongly on tip and bubble geometry and on tip and substrate material, and are very sensitive to the presence of contaminations that alter the interfacial tension. In particular, nanobubbles interacted differently with hydrophilic and hydrophobic AFM tips, which resulted in qualitatively and quantitatively different force curves measured on the bubbles in the experiments. To minimize bubble deformation and obtain reliable AFM results, nanobubbles must be measured with a sharp hydrophilic tip and with a cantilever having a very low spring constant in a contamination-free system.

Tip-enhanced near-field optical microscopy

PubMed Central

Mauser, Nina; Hartschuh, Achim

2013-01-01

Tip-enhanced near-field optical microscopy (TENOM) is a scanning probe technique capable of providing a broad range of spectroscopic information on single objects and structured surfaces at nanometer spatial resolution and with highest detection sensitivity. In this review, we first illustrate the physical principle of TENOM that utilizes the antenna function of a sharp probe to efficiently couple light to excitations on nanometer length scales. We then discuss the antenna-induced enhancement of different optical sample responses including Raman scattering, fluorescence, generation of photocurrent and electroluminescence. Different experimental realizations are presented and several recent examples that demonstrate the capabilities of the technique are reviewed. PMID:24100541

Predicting casualties implied by TIPs

NASA Astrophysics Data System (ADS)

Trendafiloski, G.; Wyss, M.; Wyss, B. M.

2009-12-01

When an earthquake is predicted, forecast, or expected with a higher than normal probability, losses are implied. We estimated the casualties (fatalities plus injured) that should be expected if earthquakes in TIPs (locations of Temporarily Increased Probability of earthquakes) defined by Kossobokov et al. (2009) should occur. We classified the predictions of losses into the categories red (more than 400 fatalities or more than 1,000 injured), yellow (between 100 and 400 fatalities), green (fewer than 100 fatalities), and gray (undetermined). TIPs in Central Chile, the Philippines, Papua, and Taiwan are in the red class, TIPs in Southern Sumatra, Nicaragua, Vanatu, and Honshu in the yellow class, and TIPs in Tonga, Loyalty Islands, Vanatu, S. Sandwich Islands, Banda Sea, and the Kuriles, are classified as green. TIPs where the losses depend moderately on the assumed point of major energy release were classified as yellow; TIPs such as in the Talaud Islands and in Tonga, where the losses depend very strongly on the location of the epicenter, were classified as gray. The accuracy of loss estimates after earthquakes with known hypocenter and magnitude are affected by uncertainties in transmission and soil properties, the composition of the building stock, the population present, and the method by which the numbers of casualties are calculated. In the case of TIPs, uncertainties in magnitude and location are added, thus we calculate losses for a range of these two parameters. Therefore, our calculations can only be considered order of magnitude estimates. Nevertheless, our predictions can come to within a factor of two of the observed numbers, as in the case of the M7.6 earthquake of October 2005 in Pakistan that resulted in 85,000 fatalities (Wyss, 2005). In subduction zones, the geometrical relationship between the earthquake source capable of a great earthquake and the population is clear because there is only one major fault plane available, thus the epicentral

Tips pentacene crystal alignment for improving performance of solution processed organic thin film transistors

NASA Astrophysics Data System (ADS)

He, Zhengran

A newly-developed p-type organic semiconductor 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) demonstrates various advantages such as high mobility, air stability and solution processibility, but at the same time its application is restricted by major issues, such as crystal misorientation and performance variation of organic thin-film transistors (OTFTs). This dissertation demonstrates several different approaches to address these issues. As a result, both crystal orientation and areal coverage can be effectively improved, leading to an enhancement of average mobility and performance consistency of OTFTs. Chapter 1 presents an introduction and background of this dissertation. Chapter 2 explores the usage of inorganic silica nanoparticles to manipulate the morphology of TIPS pentacene thin films and the performance of solution-processed organic OTFTs. The resultant drop-cast films yield improved morphological uniformity at ~10% SiO2 loading, which also leads to a 3-fold increase in average mobility and nearly 4-times reduction in the ratio of standard deviation of mobility (μStdev) to average mobility (μAvg). The experimental results suggest that the SiO2 nanoparticles mostly aggregate at TIPS pentacene grain boundaries, and that 10% nanoparticle concentration effectively reduces the undesirable crystal misorientation without considerably compromising TIPS pentacene crystallinity. Chapter 3 discusses the utilization of air flow to effectively reduce the TIPS pentacene crystal anisotropy and enhance performance consistency in OTFTs. Under air-flow navigation (AFN), TIPS pentacene forms thin films with improved crystal orientation and increased areal coverage, which subsequently lead to a four-fold increase of average hole mobility and one order of magnitude enhancement in performance consistency. Chapter 4 investigates the critical roles of lateral and vertical phase separation in the performance of the next-generation organic and hybrid electronic

On the development of a magnetoresistive sensor for blade tip timing and blade tip clearance measurement systems.

PubMed

Tomassini, R; Rossi, G; Brouckaert, J-F

2016-10-01

A simultaneous blade tip timing (BTT) and blade tip clearance (BTC) measurement system enables the determination of turbomachinery blade vibrations and ensures the monitoring of the existing running gaps between the blade tip and the casing. This contactless instrumentation presents several advantages compared to the well-known telemetry system with strain gauges, at the cost of a more complex data processing procedure. The probes used can be optical, capacitive, eddy current as well as microwaves, everyone with its dedicated electronics and many existing different signal processing algorithms. Every company working in this field has developed its own processing method and sensor technology. Hence, repeating the same test with different instrumentations, the answer is often different. Moreover, rarely it is possible to achieve reliability for in-service measurements. Developments are focused on innovative instrumentations and a common standard. This paper focuses on the results achieved using a novel magnetoresistive sensor for simultaneous tip timing and tip clearance measurements. The sensor measurement principle is described. The sensitivity to gap variation is investigated. In terms of measurement of vibrations, experimental investigations were performed at the Air Force Institute of Technology (ITWL, Warsaw, Poland) in a real aeroengine and in the von Karman Institute (VKI) R2 compressor rig. The advantages and limitations of the magnetoresistive probe for turbomachinery testing are highlighted.

On the development of a magnetoresistive sensor for blade tip timing and blade tip clearance measurement systems

NASA Astrophysics Data System (ADS)

Tomassini, R.; Rossi, G.; Brouckaert, J.-F.

2016-10-01

A simultaneous blade tip timing (BTT) and blade tip clearance (BTC) measurement system enables the determination of turbomachinery blade vibrations and ensures the monitoring of the existing running gaps between the blade tip and the casing. This contactless instrumentation presents several advantages compared to the well-known telemetry system with strain gauges, at the cost of a more complex data processing procedure. The probes used can be optical, capacitive, eddy current as well as microwaves, everyone with its dedicated electronics and many existing different signal processing algorithms. Every company working in this field has developed its own processing method and sensor technology. Hence, repeating the same test with different instrumentations, the answer is often different. Moreover, rarely it is possible to achieve reliability for in-service measurements. Developments are focused on innovative instrumentations and a common standard. This paper focuses on the results achieved using a novel magnetoresistive sensor for simultaneous tip timing and tip clearance measurements. The sensor measurement principle is described. The sensitivity to gap variation is investigated. In terms of measurement of vibrations, experimental investigations were performed at the Air Force Institute of Technology (ITWL, Warsaw, Poland) in a real aeroengine and in the von Karman Institute (VKI) R2 compressor rig. The advantages and limitations of the magnetoresistive probe for turbomachinery testing are highlighted.

Parametric analysis of swept-wing geometry with sheared wing tips

NASA Technical Reports Server (NTRS)

Fremaux, C. M.; Vijgen, P. M. H. W.; Van Dam, C. P.

1990-01-01

A computational parameter study is presented of potential reductions in induced drag and increases in lateral-directional stability due to sheared wing tips attached to an untwisted wing of moderate sweep and aspect ratio. Sheared tips are swept and tapered wing-tip devices mounted in the plane of the wing. The induced-drag results are obtained using an inviscid, incompressible surface-panel method that models the nonlinear effects due to the deflected and rolled-up wake behind the lifting surface. The induced-drag results with planar sheared tips are compared to straight-tapered tip extensions and nonplanar winglet geometries. The lateral-directional static-stability characteristics of the wing with sheared tips are estimated using a quasi-vortex-lattice method. For certain combinations of sheared-tip sweep and taper, both the induced efficiency of the wing and the relevant static-stability derivatives are predicted to increase compared to the wing with a straight-tapered tip modification.

Energy output reduction and surface alteration of quartz and sapphire tips following Er:YAG laser contact irradiation for tooth enamel ablation.

PubMed

Eguro, Toru; Aoki, Akira; Maeda, Toru; Takasaki, Aristeo Atsushi; Hasegawa, Mitsuru; Ogawa, Masaaki; Suzuki, Takanori; Yonemoto, Kazuaki; Ishikawa, Isao; Izumi, Yuichi; Katsuumi, Ichiroh

2009-10-01

Despite the recent increase in application of Er:YAG laser for various dental treatments, limited information is available regarding the contact tips. This study examined the changes in energy output and surface condition of quartz and sapphire contact tips after Er:YAG laser contact irradiation for tooth enamel ablation. Ten sets of unused quartz or sapphire contact tips were employed for contact irradiation to sound enamel of extracted teeth. The teeth were irradiated with Er:YAG laser at approximately 75 J/cm(2)/pulse and 20 Hz under water spray for 60 minutes. The energy output was measured before and every 5 minutes after irradiation, and the changes in morphology and chemical composition of the contact surface were analyzed. The energy output significantly decreased with time in both tips. The energy output from the sapphire tips was generally higher on average than that of the quartz. The contact surfaces of all the used quartz tips were concave and irregular. Most of the sapphire tips also appeared rough with crater formation and fractures, except for a few tips in which a high energy output and the original smooth surface were maintained. Spots of melted tooth substances were seen attached to the surface of both tips. In contact enamel ablation, the sapphire tip appeared to be more resistant than the quartz tip. The quartz tips showed similar patterns of energy reduction and surface alteration, whereas the sapphire tips revealed a wider and more characteristic variation among tips. Lasers Surg. Med. 41:595-604, 2009. (c) 2009 Wiley-Liss, Inc.

Root tips moving through soil

PubMed Central

Curlango-Rivera, Gilberto

2011-01-01

Root elongation occurs by the generation of new cells from meristematic tissue within the apical 1–2 mm region of root tips. Therefore penetration of the soil environment is carried out by newly synthesized plant tissue, whose cells are inherently vulnerable to invasion by pathogens. This conundrum, on its face, would seem to reflect an intolerable risk to the successful establishment of root systems needed for plant life. Yet root tip regions housing the meristematic tissues repeatedly have been found to be free of microbial infection and colonization. Even when spore germination, chemotaxis, and/or growth of pathogens are stimulated by signals from the root tip, the underlying root tissue can escape invasion. Recent insights into the functions of root border cells, and the regulation of their production by transient exposure to external signals, may shed light on long-standing observations. PMID:21455030

Regulation of Histone Acetyltransferase TIP60 Function by Histone Deacetylase 3

PubMed Central

Yi, Jingjie; Huang, Xiangyang; Yang, Yuxia; Zhu, Wei-Guo; Gu, Wei; Luo, Jianyuan

2014-01-01

The key member of the MOZ (monocyticleukaemia zinc finger protein), Ybf2/Sas3, Sas2, and TIP60 acetyltransferases family, Tat-interactive protein, 60 kD (TIP60), tightly modulates a wide array of cellular processes, including chromatin remodeling, gene transcription, apoptosis, DNA repair, and cell cycle arrest. The function of TIP60 can be regulated by SIRT1 through deacetylation. Here we found that TIP60 can also be functionally regulated by HDAC3. We identified six lysine residues as its autoacetylation sites. Mutagenesis of these lysines to arginines completely abolishes the autoacetylation of TIP60. Overexpression of HDAC3 increases TIP60 ubiquitination levels. However, unlike SIRT1, HDAC3 increased the half-life of TIP60. Further study found that HDAC3 colocalized with TIP60 both in the nucleus and the cytoplasm, which could be the reason why HDAC3 can stabilize TIP60. The deacetylation of TIP60 by both SIRT1 and HDAC3 reduces apoptosis induced by DNA damage. Knockdown of HDAC3 in cells increased TIP60 acetylation levels and increased apoptosis after DNA damage. Together, our findings provide a better understanding of TIP60 regulation mechanisms, which is a significant basis for further studies of its cellular functions. PMID:25301942

Database Search Strategies & Tips. Reprints from the Best of "ONLINE" [and]"DATABASE."

ERIC Educational Resources Information Center

Online, Inc., Weston, CT.

Reprints of 17 articles presenting strategies and tips for searching databases online appear in this collection, which is one in a series of volumes of reprints from "ONLINE" and "DATABASE" magazines. Edited for information professionals who use electronically distributed databases, these articles address such topics as: (1)…

Turbine-blade tip clearance and tip timing measurements using an optical fiber bundle sensor

NASA Astrophysics Data System (ADS)

Garcia, Iker; Beloki, Josu; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon

2013-04-01

Traditional limitations of capacitive, inductive or discharging probe sensor for tip timing and tip clearance measurements are overcome by reflective intensity modulated optical fiber sensors. This paper presents the signals and results corresponding to a one stage turbine rig which rotor has 146 blades, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on turbine casing. It is composed of a central illuminating fiber that guides the light from a laser to the turbine blade, and two concentric rings of receiving fibers that collect the reflected light. Two photodetectors turn this reflected light signal from the receiving rings into voltage. The electrical signals are acquired and saved by a high-sample-rate oscilloscope. In tip clearance calculations the ratio of the signals provided by each ring of receiving fibers is evaluated and translated into distance. In the case of tip timing measurements, only one of the signals is considered to get the arrival time of the blade. The differences between the real and theoretical arrival times of the blades are used to obtain the deflections amplitude. The system provides the travelling wave spectrum, which presents the average vibration amplitude of the blades at a certain nodal diameter. The reliability of the results in the turbine rig testing facilities suggests the possibility of performing these measurements in real turbines under real working conditions.

Fund-raising tips for nurse leaders and nurse executives.

PubMed

Fitzpatrick, Joyce J

2014-01-01

Fund-raising may be new to most nurse leaders and executives. This article focuses on dispelling the myths and mystery that surrounds nursing philanthropy. Key myths are addressed with supporting information to dispel them. Several practical tips are presented to enhance nurse leaders' involvement in philanthropy. Two recent gifts to hospital nursing departments are described as exemplars of relationship building and of nurses investing in their own future and that of the profession.

Prediction of Unshsrouded Rotor Blade Tip Heat Transfer

NASA Technical Reports Server (NTRS)

Ameri, A. A.; Steinthorsson, E.

1994-01-01

The rate of heat transfer on the tip of a turbine rotor blade and on the blade surface in the vicinity of the tip, was successfully predicted. The computations were performed with a multiblock computer code which solves the Reynolds Averaged Navier-Stokes equations using an efficient multigrid method. The case considered for the present calculations was the Space Shuttle Main Engine (SSME) high pressure fuel side turbine. The predictions of the blade tip heat transfer agreed reasonably well with the experimental measurements using the present level of grid refinement. On the tip surface, regions with high rate of heat transfer was found to exist close to the pressure side and suction side edges. Enhancement of the heat transfer was also observed on the blade surface near the tip. Further comparison of the predictions was performed with results obtained from correlations based on fully developed channel flow.

Numerical analysis of turbine blade tip treatments

NASA Technical Reports Server (NTRS)

Gopalaswamy, Nath S.; Whitaker, Kevin W.

1992-01-01

Three-dimensional solutions of the Navier-Stokes equations for a turbine blade with a turning angle of 180 degrees have been computed, including blade tip treatments involving cavities. The geometry approximates a preliminary design for the GGOT (Generic Gas Oxidizer Turbine). The data presented here will be compared with experimental data to be obtained from a linear cascade using original GGOT blades. Results have been computed for a blade with 1 percent clearance, based on chord, and three different cavity sizes. All tests were conducted at a Reynolds number of 4 x 10 exp 7. The grid contains 39,440 points with 10 spanwise planes in the tip clearance region of 5.008E-04 m. Streamline plots and velocity vectors together with velocity divergence plots reveal the general flow behavior in the clearance region. Blade tip temperature calculations suggest placement of a cavity close to the upstream side of the blade tip for reduction of overall blade tip temperature. The solutions do not account for the relative motion between the endwall and the turbine blade. The solutions obtained are generally consistent with previous work done in this area,

Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sigala, Barbara; Edwards, Mina; Puri, Teena

2005-11-01

TIP48 is a highly conserved eukaryotic AAA{sup +} protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis,more » TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis.« less

Method of cooling gas only nozzle fuel tip

DOEpatents

Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

2002-01-01

A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

A review of turbine blade tip heat transfer.

PubMed

Bunker, R S

2001-05-01

This paper presents a review of the publicly available knowledge base concerning turbine blade tip heat transfer, from the early fundamental research which laid the foundations of our knowledge, to current experimental and numerical studies utilizing engine-scaled blade cascades and turbine rigs. Focus is placed on high-pressure, high-temperature axial-turbine blade tips, which are prevalent in the majority of today's aircraft engines and power generating turbines. The state of our current understanding of turbine blade tip heat transfer is in the transitional phase between fundamentals supported by engine-based experience, and the ability to a priori correctly predict and efficiently design blade tips for engine service.

Wind-tunnel test of an articulated helicopter rotor model with several tip shapes

NASA Technical Reports Server (NTRS)

Berry, J. D.; Mineck, R. E.

1980-01-01

Six interchangeable tip shapes were tested: a square (baseline) tip, an ogee tip, a subwing tip, a swept tip, a winglet tip, and a short ogee tip. In hover at the lower rotational speeds the swept, ogee, and short ogee tips had about the same torque coefficient, and the subwing and winglet tips had a larger torque coefficient than the baseline square tip blades. The ogee and swept tip blades required less torque coefficient at lower rotational speeds and roughly equivalent torque coefficient at higher rotational speeds compared with the baseline square tip blades in forward flight. The short ogee tip required higher torque coefficient at higher lift coefficients than the baseline square tip blade in the forward flight test condition.

User's manual for PEPSIG NASA tip vortex version

NASA Technical Reports Server (NTRS)

Tsai, Tommy M.; Dejong, Frederick J.; Levy, Ralph

1988-01-01

The tip vortex flowfield plays a significant role in the performance of advanced aircraft propellers. The flowfield in the tip region is complex, three-dimensional and viscous with large secondary velocities. A computer code was developed to predict the tip vortex flowfield of advanced aircraft propellers. This document is the user's manual. The analysis and a series of test cases are presented in NASA-CR-182179.

Tip-enhanced Raman spectroscopy of lipid bilayers in water with an alumina- and silver-coated tungsten tip.

PubMed

Nakata, Atsushi; Nomoto, Tomonori; Toyota, Taro; Fujinami, Masanori

2013-01-01

Tip-enhanced Raman spectroscopy (TERS) of supported phospholipid bilayers in an aqueous environment is discussed in this paper. Two bilayer membranes were examined: 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We fabricated alumina- and silver-coated tungsten tips that are very robust in water. There was a large time-dependence in the TERS spectra for the DOPC bilayers, whereas no such time-dependence was observed in the DPPC bilayer spectra under the probe tip. The spectral changes of DOPC bilayers are discussed in terms of the fluidity of the liquid crystalline phase. Time-resolved TERS thus has the potential to characterize inhomogeneity and diffusion in fluidic phospholipid bilayer membranes.

Thulium fiber laser lithotripsy using small spherical distal fiber tips

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

2016-02-01

This study tests a 100-μm-core fiber with 300-μm-diameter ball tip during Thulium fiber laser (TFL) lithotripsy. The TFL was operated at 1908 nm wavelength with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times measured, and ablation rates calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to observe ball tip degradation and determine number of procedures completed before need to replace fiber. Saline irrigation rates and ureteroscope deflection were measured with and without TFL fiber present. There was no statistical difference (P > 0.05) between stone ablation rates for single-use ball tip fiber (1.3 +/- 0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3 +/- 0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3 +/- 0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged > 4 stone procedures before decline in stone ablation rates due to mechanical damage at front surface of ball tip. The small fiber diameter did not impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and the ureter without risk of scope damage or tissue perforation, and without compromising stone ablation efficiency during TFL ablation of kidney stones.

Evaluation of the tip-bending response in clinically used endoscopes.

PubMed

Rozeboom, Esther D; Reilink, Rob; Schwartz, Matthijs P; Fockens, Paul; Broeders, Ivo A M J

2016-04-01

Endoscopic interventions require accurate and precise control of the endoscope tip. The endoscope tip response depends on a cable pulling system, which is known to deliver a significantly nonlinear response that eventually reduces control. It is unknown whether the current technique of endoscope tip control is adequate for a future of high precision procedures, steerable accessories, and add-on robotics. The aim of this study was to determine the status of the tip response of endoscopes used in clinical practice. We evaluated 20 flexible colonoscopes and five gastroscopes, used in the endoscopy departments of a Dutch university hospital and two Dutch teaching hospitals, in a bench top setup. First, maximal tip bending was determined manually. Next, the endoscope navigation wheels were rotated individually in a motor setup. Tip angulation was recorded with a USB camera. Cable slackness was derived from the resulting hysteresis plot. Only two of the 20 colonoscopes (10 %) and none of the five gastroscopes reached the maximal tip angulation specified by the manufacturer. Four colonoscopes (20 %) and none of the gastroscopes demonstrated the recommended cable tension. Eight colonoscopes (40 %) had undergone a maintenance check 1 month before the measurements were made. The tip responses of these eight colonoscopies did not differ significantly from the tip responses of the other colonoscopes. This study suggests that the majority of clinically used endoscopes are not optimally tuned to reach maximal bending angles and demonstrate adequate tip responses. We suggest a brief check before procedures to predict difficulties with bending angles and tip responses.

Excitation of surface plasmons in Al-coated SNOM tips

NASA Astrophysics Data System (ADS)

Palm, Viktor; Rähn, Mihkel; Jäme, Joonas; Hizhnyakov, Vladimir

2012-10-01

The mesoscopic effect of spectral modulation occurring due to the interference of two photonic fiber modes filtered out by a metal-coated SNOM tip is used to observe the surface plasmon polariton (SPP) excitation in SNOM tips. In a spectrum of the broadband light transmitted by a SNOM tip a region of highly regular spectral modulation can be found, indicating the spectral interval in which only two photonic modes (apparently HE11 and TM01) are transmitted with significant and comparable amplitudes. The modulation period yields the value of optical path difference (OPD) for this pair of modes. Due to the multimode fiber's inherent modal dispersion, this OPD value depends linearly on the fiber tail length l. An additional contribution to OPD can be generated in a metal-coated SNOM tip due to a mode-dependent photon-plasmon coupling strength resulting in generation of SPPs with different propagation velocities. For an Al-coated 200 nm SNOM tip spectra of transmitted light have been registered for ten different l values. An extrapolation of the linear OPD (l) dependence to l=0 yields a significant residual OPD value, indicating according to our theoretical considerations a mode-selective SPP excitation in the metal-coated tip. The modal dispersion is shown to switch its sign in the SNOM tip. First results of analogous experiments with an Al-coated 150 nm SNOM tip confirm our conclusions.

A Mobile App Offering Distractions and Tips to Cope With Cigarette Craving: A Qualitative Study

PubMed Central

Smith, Wally; Pearce, Jon; Borland, Ron

2014-01-01

Background Despite considerable effort, most smokers relapse within a few months after quitting due to cigarette craving. The widespread adoption of mobile phones presents new opportunities to provide support during attempts to quit. Objective To design and pilot a mobile app "DistractMe" to enable quitters to access and share distractions and tips to cope with cigarette cravings. Methods A qualitative study with 14 smokers who used DistractMe on their mobiles during the first weeks of their quit attempt. Based on interviews, diaries, and log data, we examined how the app supported quitting strategies. Results Three distinct techniques of coping when using DistractMe were identified: diversion, avoidance, and displacement. We further identified three forms of engagement with tips for coping: preparation, fortification, and confrontation. Overall, strategies to prevent cravings and their effects (avoidance, displacement, preparation, and fortification) were more common than immediate coping strategies (diversion and confrontation). Tips for coping were more commonly used than distractions to cope with cravings, because they helped to fortify the quit attempt and provided opportunities to connect with other users of the application. However, distractions were important to attract new users and to facilitate content sharing. Conclusions Based on the qualitative results, we recommend that mobile phone-based interventions focus on tips shared by peers and frequent content updates. Apps also require testing with larger groups of users to assess whether they can be self-sustaining. PMID:25099632

Wettability of AFM tip influences the profile of interfacial nanobubbles

NASA Astrophysics Data System (ADS)

Teshima, Hideaki; Takahashi, Koji; Takata, Yasuyuki; Nishiyama, Takashi

2018-02-01

To accurately characterize the shape of interfacial nanobubbles using atomic force microscopy (AFM), we investigated the effect of wettability of the AFM tip while operating in the peak force tapping (PFT) mode. The AFM tips were made hydrophobic and hydrophilic by Teflon AF coating and oxygen plasma treatment, respectively. It was found that the measured base radius of nanobubbles differed between AFM height images and adhesion images, and that this difference depended on the tip wettability. The force curves obtained during the measurements were also different depending on the wettability, especially in the range of the tip/nanobubble interaction and in the magnitude of the maximum attractive force in the retraction period. The difference suggests that hydrophobic tips penetrate the gas/liquid interface of the nanobubbles, with the three phase contact line being pinned on the tip surface; hydrophilic tips on the other hand do not penetrate the interface. We then quantitatively estimated the pinning position and recalculated the true profiles of the nanobubbles by comparing the height images and adhesion images. As the AFM tip was made more hydrophilic, the penetration depth decreased and eventually approached zero. This result suggests that the PFT measurement using a hydrophilic tip is vital for the acquisition of reliable nanobubble profiles.

Kaplan turbine tip vortex cavitation - analysis and prevention

NASA Astrophysics Data System (ADS)

Motycak, L.; Skotak, A.; Kupcik, R.

2012-11-01

The work is focused on one type of Kaplan turbine runner cavitation - a tip vortex cavitation. For detailed description of the tip vortex, the CFD analysis is used. On the basis of this analysis it is possible to estimate the intensity of cavitating vortex core, danger of possible blade surface and runner chamber cavitation pitting. In the paper, the ways how to avoid the pitting effect of the tip vortex are described. In order to prevent the blade surface against pitting, the following possibilities as the change of geometry of the runner blade, dimension of tip clearance and finally the installation of the anti-cavitation lips are discussed. The knowledge of the shape and intensity of the tip vortex helps to design the anti-cavitation lips more sophistically. After all, the results of the model tests of the Kaplan runner with or without anti-cavitation lips and the results of the CFD analysis are compared.

Nonlinear Aerodynamics and the Design of Wing Tips

NASA Technical Reports Server (NTRS)

Kroo, Ilan

1991-01-01

The analysis and design of wing tips for fixed wing and rotary wing aircraft still remains part art, part science. Although the design of airfoil sections and basic planform geometry is well developed, the tip regions require more detailed consideration. This is important because of the strong impact of wing tip flow on wing drag; although the tip region constitutes a small portion of the wing, its effect on the drag can be significant. The induced drag of a wing is, for a given lift and speed, inversely proportional to the square of the wing span. Concepts are proposed as a means of reducing drag. Modern computational methods provide a tool for studying these issues in greater detail. The purpose of the current research program is to improve the understanding of the fundamental issues involved in the design of wing tips and to develop the range of computational and experimental tools needed for further study of these ideas.

Italian: Area Background Information.

ERIC Educational Resources Information Center

Defense Language Inst., Washington, DC.

This booklet has been assembled in order to provide students of Italian with a compact source of cultural information on their target area. Chapters include discussion of: (1) introduction to Italian; (2) origins of the Italian population; (3) geography; (4) history including the Roman Era, the Middle Ages, the Renaissance, the "Risorgimento," and…

In situ scanning tunneling microscope tip treatment device for spin polarization imaging

DOEpatents

Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

2008-04-22

A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

The Evolution of Transjugular Intrahepatic Portosystemic Shunt: Tips

PubMed Central

Fanelli, Fabrizio

2014-01-01

Since Richter's description in the literature in 1989 of the first procedure on human patients, transjugular intrahepatic portosystemic shunt (TIPS) has been worldwide considered as a noninvasive technique to manage portal hypertension complications. TIPS succeeds in lowering the hepatic sinusoidal pressure and in increasing the circulatory flow, thus reducing sodium retention, ascites recurrence, and variceal bleeding. Required several revisions of the shunt TIPS can be performed in case of different conditions such as hepatorenal syndrome, hepatichydrothorax, portal vein thrombosis, and Budd-Chiari syndrome. Most of the previous studies on TIPS procedure were based on the use of bare stents and most patients chose TIPS 2-3 years after traditional treatment, thus making TIPS appear to be not superior to endoscopy in survival rates. Bare stents were associated with higher incidence of shunt failure and consequently patients required several revisions during the follow-up. With the introduction of a dedicated e-PTFE covered stent-graft, these problems were completely solved, No more reinterventions are required with a tremendous improvement of patient's quality of life. One of the main drawbacks of the use of e-PTFE covered stent-graft is higher incidence of hepatic encephalopathy. In those cases refractory to the conventional medical therapy, a shunt reduction must be performed. PMID:27335841

Final Technical Report: Electrohydrodynamic Tip Streaming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basaran, Osman

2016-01-06

When subjected to strong electric fields, liquid drops and films form conical tips and emit thin jets from their tips. Such electrodydrodynamic (EDH) tip streaming or cone-jetting phenomena, which are sometimes referred to as electrospraying, occur widely in nature, e.g., in ejection of streams of small charged drops from pointed tips of raindrops in thunderclouds, and technology, e.g., in electrospray mass spectrometry or electric field-driven solvent extraction. More recently, EHD cone-jetting has emerged as a powerful technique for direct printing of solar cells, micro- and nano- particle production, and microencapsulation for controlled release. In many of the aforementioned situations, ofmore » equal importance to the processes by which one drop disintegrates to form several drops are those by which (a) two drops come together and coalesce and (b) two drops are coupled to form a double droplet system (DDS) or a capillary switch (CS). the main objective of this research program is to advance through simulation, theory, and experiment the breakup, coalescence, and oscillatory dynamics of single and pairs of charged as well as uncharged drops.« less

Quantification of holmium:YAG optical tip degradation

NASA Astrophysics Data System (ADS)

Mues, Adam C.; Teichman, Joel M. H.; Knudsen, Bodo E.

2009-02-01

The holmium:yttrium aluminum garnet (YAG) laser is the gold standard laser for intracorporeal lithotripsy. Optical fibers are utilized to transmit laser energy to the surface of a stone for fragmentation. During lithotripsy, fiber tip degradation (burn back) can occur. The exact mechanism for tip degradation and related factors are not completely understood, and have not been investigated. This characteristic is important because fiber burn back may affect diminish fragmentation efficiency, increase operative time, and increase cost due to the need for fiber replacement. We hypothesize that fiber tip degradation (burn back) varies amongst different commercially available holmium:YAG laser fibers.

Tip Fence for Reduction of Lift-Generated Airframe Noise

NASA Technical Reports Server (NTRS)

Ross, James C. (Inventor); Storms, Bruce L. (Inventor)

1998-01-01

The present invention is directed toward a unique lift-generated noise reduction apparatus. This apparatus includes a plurality of tip fences that are secured to the trailing and leading assemblies of the high-lift system, as close as possible to the discontinuities where the vortices are most likely to form. In one embodiment, these tip fences are secured to some or all of the outboard and inboard tips of the wing slats and flaps. The tip fence includes a generally flat, or an aerodynamically shaped plate or device that could be formed of almost any rigid material, such as metal, wood, plastic, fiber glass, aluminum, etc. In a preferred embodiment, the tip fences extend below and perpendicularly to flaps and the slats to which they are attached, such that these tip fences are aligned with the nominal free stream velocity of the aircraft. In addition to reducing airframe noise, the tip fence tends to decrease drag and to increase lift, thus improving the overall aerodynamic performance of the aircraft. Another advantage presented by the tip fence lies in the simplicity of its design, its elegance, and its ready ability to fit on the wing components, such as the flaps and the slats. Furthermore, it does not require non-standard materials or fabrication techniques, and it can be readily, easily and inexpensively retrofited on most of the existing aircraft, with minimal design changes.

Biophysics and clinical utility of irrigated-tip radiofrequency catheter ablation.

PubMed

Houmsse, Mahmoud; Daoud, Emile G

2012-01-01

Catheter ablation by radiofrequency (RF) energy has successfully eliminated cardiac tachyarrhythmias. RF ablation lesions are created by thermal energy. Electrode catheters with 4-mm-tips have been adequate to ablate arrhythmias located near the endocardium; however, the 4-mm-tip electrode does not readily ablate deeper tachyarrhythmia substrate. With 8- and 10-mm-tip RF electrodes, ablation lesions were larger; yet, these catheters are associated with increased risk for coagulum, char and thrombus formation, as well as myocardial steam rupture. Cooled-tip catheter technology was designed to cool the electrode tip, prevent excessive temperatures at the electrode tip-tissue interface, and thus allow continued delivery of RF current into the surrounding tissue. This ablation system creates larger and deeper ablation lesions and minimizes steam pops and thrombus formation. The purpose of this article is to review cooled-tip RF ablation biophysics and outcomes of clinical studies as well as to discuss future technological improvements.

Evaluation of cutting efficiency of ultrasonic tips used in orthograde endodontic treatment.

PubMed

Lin, Yu-Heng; Mickel, André K; Jones, Jefferson J; Montagnese, Thomas A; González, Alvaro F

2006-04-01

The purpose of the present study was to evaluate the cutting efficiency of the three different ultrasonic tips for orthograde endodontic treatment: stainless steel, zirconium nitride-coated, and diamond-coated tips. An ultrasonic handpiece was mounted on a custom-made automated balance, and each tip repeatedly penetrated dental stone blocks to a depth of 3 mm for 10 times. The amount of time taken to penetrate 3 mm of stone was measured. The diamond-coated tips showed significantly greater cutting efficiency than either stainless steel tips or zirconium-nitride coated tips. The stainless steel tips showed initial better cutting efficiency, but over time , there is no significant difference between the cutting efficiency of the stainless steel tips and the zirconium nitride coated tips. The diamond coated tips were the only group that showed breakage in this study.

Substance Abuse Treatment and Domestic Violence. Treatment Improvement Protocol (TIP) Series 25.

ERIC Educational Resources Information Center

Cook, Paddy; Gartner, Constance Grant; Markl, Lise; Henderson, Randi; Brooks, Margaret K.; Wesson, Donald; Dogoloff, Mary Lou; Vitzthum, Virginia; Hayes, Elizabeth

The major goal of this TIP, on the best practice guidelines to improve the treatment of substance abuse, is to provide clinicians, educators, and paraprofessionals with the latest findings concerning domestic violence. The information is intended to educate providers about the needs and behaviors of batterers and survivors, and how to tailor…

Computation of the tip vortex flowfield for advanced aircraft propellers

NASA Technical Reports Server (NTRS)

Tsai, Tommy M.; Dejong, Frederick J.; Levy, Ralph

1988-01-01

The tip vortex flowfield plays a significant role in the performance of advanced aircraft propellers. The flowfield in the tip region is complex, three-dimensional and viscous with large secondary velocities. An analysis is presented using an approximate set of equations which contains the physics required by the tip vortex flowfield, but which does not require the resources of the full Navier-Stokes equations. A computer code was developed to predict the tip vortex flowfield of advanced aircraft propellers. A grid generation package was developed to allow specification of a variety of advanced aircraft propeller shapes. Calculations of the tip vortex generation on an SR3 type blade at high Reynolds numbers were made using this code and a parametric study was performed to show the effect of tip thickness on tip vortex intensity. In addition, calculations of the tip vortex generation on a NACA 0012 type blade were made, including the flowfield downstream of the blade trailing edge. Comparison of flowfield calculations with experimental data from an F4 blade was made. A user's manual was also prepared for the computer code (NASA CR-182178).

Identification and functional analysis of endothelial tip cell-enriched genes.

PubMed

del Toro, Raquel; Prahst, Claudia; Mathivet, Thomas; Siegfried, Geraldine; Kaminker, Joshua S; Larrivee, Bruno; Breant, Christiane; Duarte, Antonio; Takakura, Nobuyuki; Fukamizu, Akiyoshi; Penninger, Josef; Eichmann, Anne

2010-11-11

Sprouting of developing blood vessels is mediated by specialized motile endothelial cells localized at the tips of growing capillaries. Following behind the tip cells, endothelial stalk cells form the capillary lumen and proliferate. Expression of the Notch ligand Delta-like-4 (Dll4) in tip cells suppresses tip cell fate in neighboring stalk cells via Notch signaling. In DLL4(+/-) mouse mutants, most retinal endothelial cells display morphologic features of tip cells. We hypothesized that these mouse mutants could be used to isolate tip cells and so to determine their genetic repertoire. Using transcriptome analysis of retinal endothelial cells isolated from DLL4(+/-) and wild-type mice, we identified 3 clusters of tip cell-enriched genes, encoding extracellular matrix degrading enzymes, basement membrane components, and secreted molecules. Secreted molecules endothelial-specific molecule 1, angiopoietin 2, and apelin bind to cognate receptors on endothelial stalk cells. Knockout mice and zebrafish morpholino knockdown of apelin showed delayed angiogenesis and reduced proliferation of stalk cells expressing the apelin receptor APJ. Thus, tip cells may regulate angiogenesis via matrix remodeling, production of basement membrane, and release of secreted molecules, some of which regulate stalk cell behavior.

Theoretical study of carbon-based tips for scanning tunnelling microscopy.

PubMed

González, C; Abad, E; Dappe, Y J; Cuevas, J C

2016-03-11

Motivated by recent experiments, we present here a detailed theoretical analysis of the use of carbon-based conductive tips in scanning tunnelling microscopy. In particular, we employ ab initio methods based on density functional theory to explore a graphitic, an amorphous carbon and two diamond-like tips for imaging with a scanning tunnelling microscope (STM), and we compare them with standard metallic tips made of gold and tungsten. We investigate the performance of these tips in terms of the corrugation of the STM images acquired when scanning a single graphene sheet. Moreover, we analyse the impact of the tip-sample distance and show that it plays a fundamental role in the resolution and symmetry of the STM images. We also explore in depth how the adsorption of single atoms and molecules in the tip apexes modifies the STM images and demonstrate that, in general, it leads to an improved image resolution. The ensemble of our results provides strong evidence that carbon-based tips can significantly improve the resolution of STM images, as compared to more standard metallic tips, which may open a new line of research in scanning tunnelling microscopy.

The inviscid pressure field on the tip of a semi-infinite wing and its application to the formation of a tip vortex

NASA Technical Reports Server (NTRS)

Hall, G. F.; Shamroth, S. J.; Mcdonald, H.; Briley, W. R.

1976-01-01

A method was developed for determining the aerodynamic loads on the tip of an infinitely thin, swept, cambered semi-infinite wing at an angle of attack which is operating subsonically in an inviscid medium and is subjected to a sinusoidal gust. Under the assumption of linearized aerodynamics, the loads on the tip are obtained by superposition of the steady aerodynamic results for angle of attack and camber, and the unsteady results for the response to the sinusoidal gust. The near field disturbance pressures in the fluid surrounding the tip are obtained by assuming a dipole representation for the loading on the tip and calculating the pressures accordingly. The near field pressures are used to drive a reduced form of the Navier-Stokes equations which yield the tip vortex formation. The combined viscid-inviscid analysis is applied to determining the pressures and examining the vortex rollup in the vicinity of an unswept, uncambered wing moving steadily at a Mach number of 0.2 at an angle of attack of 0.1 rad. The viscous tip flow calculation shows features expected in the tip flow such as the qualitatively proper development of boundary layers on both the upper and lower airfoil surfaces. In addition, application of the viscous solution leads to the generation of a circular type flow pattern above the airfoil suction surface.

Blade tip timing (BTT) uncertainties

NASA Astrophysics Data System (ADS)

Russhard, Pete

2016-06-01

Blade Tip Timing (BTT) is an alternative technique for characterising blade vibration in which non-contact timing probes (e.g. capacitance or optical probes), typically mounted on the engine casing (figure 1), and are used to measure the time at which a blade passes each probe. This time is compared with the time at which the blade would have passed the probe if it had been undergoing no vibration. For a number of years the aerospace industry has been sponsoring research into Blade Tip Timing technologies that have been developed as tools to obtain rotor blade tip deflections. These have been successful in demonstrating the potential of the technology, but rarely produced quantitative data, along with a demonstration of a traceable value for measurement uncertainty. BTT technologies have been developed under a cloak of secrecy by the gas turbine OEM's due to the competitive advantages it offered if it could be shown to work. BTT measurements are sensitive to many variables and there is a need to quantify the measurement uncertainty of the complete technology and to define a set of guidelines as to how BTT should be applied to different vehicles. The data shown in figure 2 was developed from US government sponsored program that bought together four different tip timing system and a gas turbine engine test. Comparisons showed that they were just capable of obtaining measurement within a +/-25% uncertainty band when compared to strain gauges even when using the same input data sets.

Analysis, design, fabrication and testing of an optical tip clearance sensor. [turbocompressor blade tips

NASA Technical Reports Server (NTRS)

Poppel, G. L.; Marple, D. T. F.; Kingsley, J. D.

1981-01-01

Analyses and the design, fabrication, and testing of an optical tip clearance sensor with intended application in aircraft propulsion control systems are reported. The design of a sensor test rig, evaluation of optical sensor components at elevated temperatures, sensor design principles, sensor test results at room temperature, and estimations of sensor accuracy at temperatures of an aircraft engine environment are discussed. Room temperature testing indicated possible measurement accuracies of less than 12.7 microns (0.5 mils). Ways to improve performance at engine operating temperatures are recommended. The potential of this tip clearance sensor is assessed.

21 CFR 870.1370 - Catheter tip occluder.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Catheter tip occluder. 870.1370 Section 870.1370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1370 Catheter tip occluder...

21 CFR 880.6025 - Absorbent tipped applicator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... stick. The device is used to apply medications to, or to take specimens from, a patient. (b...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices § 880.6025 Absorbent tipped applicator. (a) Identification. An absorbent tipped applicator is a...

21 CFR 870.1370 - Catheter tip occluder.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter tip occluder. 870.1370 Section 870.1370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1370 Catheter tip occluder...

Sharp Tips on the Atomic Force Microscope

NASA Technical Reports Server (NTRS)

2008-01-01

This image shows the eight sharp tips of the NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA.

The microscope maps the shape of particles in three dimensions by scanning them with one of the tips at the end of a beam. For the AFM image taken, the tip at the end of the upper right beam was used. The tip pointing up in the enlarged image is the size of a smoke particle at its base, or 2 microns. This image was taken with a scanning electron microscope before Phoenix launched on August 4, 2007.

The AFM was developed by a Swiss-led consortium in collaboration with Imperial College London.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Some observations of tip-vortex cavitation

NASA Astrophysics Data System (ADS)

Arndt, R. E. A.; Arakeri, V. H.; Higuchi, H.

1991-08-01

Cavitation has been observed in the trailing vortex system of an elliptic platform hydrofoil. A complex dependence on Reynolds number and gas content is noted at inception. Some of the observations can be related to tension effects associated with the lack of sufficiently large-sized nuclei. Inception measurements are compared with estimates of pressure in the vortex obtained from LDV measurements of velocity within the vortex. It is concluded that a complete correlation is not possible without knowledge of the fluctuating levels of pressure in tip-vortex flows. When cavitation is fully developed, the observed tip-vortex trajectory flows. When cavitation is fully developed, the observed tip-vortex trajectory shows a surprising lack of dependence on any of the physical parameters varied, such as angle of attack, Reynolds number, cavitation number, and dissolved gas content.

100 Consejos para los Padres (100 Tips for Parents).

ERIC Educational Resources Information Center

Department of Education, Washington, DC.

Noting that involved parents can improve their children's chances of succeeding in school, this packet of Spanish-language cards offers 100 tips created to help parents become more involved in their child's education. Following a card of general tips on becoming involved, tips are offered in the following topic areas: keeping a child alcohol,…

Novel cylindrical illuminator tip for ultraviolet light delivery

NASA Astrophysics Data System (ADS)

Shangguan, HanQun; Haw, Thomas E.; Gregory, Kenton W.; Casperson, Lee W.

1993-06-01

The design, processing, and sequential testing of a novel cylindrical diffusing optical fiber tip for ultraviolet light delivery is described. This device has been shown to uniformly (+/- 15%) illuminate angioplasty balloons, 20 mm in length, that are used in an experimental photochemotherapeutic treatment of swine intimal hyperplasia. Our experiments show that uniform diffusing tips of < 400 micron diameter can be reliably constructed for this and other interstitial applications. Modeling results indicate that this design is scalable to smaller diameters. The diffusing tips are made by stripping the protective buffer and etching away the cladding over a length of 20 mm from the fiber tip and replacing it with a thin layer of optical epoxy mixed with Al2O3 powder. To improve the uniformity and ease of fabrication, we have evaluated a new device configuration where the tip is etched into a modified conical shape, and the distal end face is polished and then coated with an optically opaque epoxy. This is shown to uniformly scatter approximately 70% of the light launched into the fiber without forward transmission.

Cooling circuit for a gas turbine bucket and tip shroud

DOEpatents

Willett, Fred Thomas; Itzel, Gary Michael; Stathopoulos, Dimitrios; Plemmons, Larry Wayne; Plemmons, Helen M.; Lewis, Doyle C.

2002-01-01

An open cooling circuit for a gas turbine bucket wherein the bucket has an airfoil portion, and a tip shroud, the cooling circuit including a plurality of radial cooling holes extending through the airfoil portion and communicating with an enlarged internal area within the tip shroud before exiting the tip shroud such that a cooling medium used to cool the airfoil portion is subsequently used to cool the tip shroud.

Carbon Monoxide Information Center

MedlinePlus Videos and Cool Tools

... Education Centers Carbon Monoxide Information Center Carbon Monoxide Information Center En Español The Invisible Killer Carbon monoxide, ... Install one and check its batteries regularly. View Information About CO Alarms Other CO Topics Safety Tips ...

Turbine blade tip clearance measurements using skewed dual optical beams of tip timing

NASA Astrophysics Data System (ADS)

Ye, De-chao; Duan, Fa-jie; Guo, Hao-tian; Li, Yangzong; Wang, Kai

2011-12-01

Optimization and active control of the clearance between turbine blades and case of the engine is identified, especially in aerospace community, as a key technology to increase engine efficiency, reduce fuel consumption and emissions and increase service life .However, the tip clearance varies during different operating conditions. Thus a reliable non-contact and online detection system is essential and ultimately used to close the tip clearance control loop. This paper described a fiber optical clearance measuring system applying skewed dual optical beams to detect the traverse time of passing blades. Two beams were specially designed with an outward angle of 18 degree and the beam spot diameters are less than 100μm within 0-4mm working range to achieve high signal-to-noise and high sensitivity. It could be theoretically analyzed that the measuring accuracy is not compromised by degradation of signal intensity caused by any number of environmental conditions such as light source instability, contamination and blade tip imperfection. Experimental tests were undertaken to achieve a high resolution of 10µm in the rotational speed range 2000-18000RPM and a measurement accuracy of 15μm, indicating that the system is capable of providing accurate and reliable data for active clearance control (ACC).

New Technique for Fabrication of Scanning Single-Electron Transistor Microscopy Tips

NASA Astrophysics Data System (ADS)

Goodwin, Eric; Tessmer, Stuart

Fabrication of glass tips for Scanning Single-Electron Transistor Microscopy (SSETM) can be expensive, time consuming, and inconsistent. Various techniques have been tried, with varying levels of success in regards to cost and reproducibility. The main requirement for SSETM tips is to have a sharp tip ending in a micron-scale flat face to allow for deposition of a quantum dot. Drawing inspiration from methods used to create tips from optical fibers for Near-Field Scanning Optical Microscopes, our group has come up with a quick and cost effective process for creating SSETM tips. By utilizing hydrofluoric acid to etch the tips and oleic acid to guide the etch profile, optical fiber tips with appropriate shaping can be rapidly prepared. Once etched, electric leads are thermally evaporated onto each side of the tip, while an aluminum quantum dot is evaporated onto the face. Preliminary results using various metals, oxide layers, and lead thicknesses have proven promising.

Thulium fiber laser lithotripsy using a muzzle brake fiber tip

NASA Astrophysics Data System (ADS)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

The Thulium fiber laser (TFL) is being explored as an alternative to Holmium:YAG laser for lithotripsy. TFL beam profile allows coupling of higher power into smaller fibers than multimode Holmium laser beam, without proximal fiber tip degradation. A smaller fiber provides more space in ureteroscope working channel for increased saline irrigation and allows maximum ureteroscope flexion. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback, but increased retropulsion. In this study, a "fiber muzzle brake" was tested for reducing fiber burnback and stone retropulsion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-OD, 360-μm-ID tube with 275-μm thru hole located 250-μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed, ex vivo. Small stones with a mass of 40 +/- 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 +/- 4 s (n=10), without distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers. The muzzle brake fiber tip provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Jagged gives endothelial tip cells an edge.

PubMed

Suchting, Steven; Eichmann, Anne

2009-06-12

Sprouting blood vessels have tip cells that lead and stalk cells that follow. Benedito et al. (2009) now show that competition between endothelial cells for the tip position is regulated by glycosylation of Notch receptors and by the opposing actions of the Notch ligands Jagged1 and Delta-like 4.

Onyx embolization with the Apollo detachable tip microcatheter: A single-center experience.

PubMed

Miller, Timothy R; Giacon, Luciano; Kole, Matthew J; Chen, Rong; Jindal, Gaurav; Gandhi, Dheeraj

2018-06-01

Purpose The Apollo Onyx Delivery Microcatheter (Ev3, Irvine, CA) is a detachable-tip microcatheter that was developed to reduce the risk of microcatheter entrapment during ethylene-vinyl alcohol copolymer (Onyx) embolizations. We report our experience with the microcatheter in a variety of neurointerventional procedures. Methods We retrospectively reviewed all Onyx embolizations performed in the head, neck, and spine using the Apollo Onyx Delivery Microcatheter from its introduction at our institution in July 2014 to August 2016. Information regarding patient diagnoses, procedural details, as well as clinical outcomes were obtained from the electronic medical record, procedure reports, and relevant angiographic imaging. Results A total of 58 arterial pedicle Onyx embolizations were performed in 37 patients. There were no cases of microcatheter entrapment, early/inadvertent tip detachment, or vessel injury upon removal of the device. There were two instances (3.5%) of leakage of Onyx from the microcatheter detachment site during embolization, which did not result in adverse sequelae. Clinical outcomes were excellent, with nearly all embolizations achieving the intended goal. In multivariate analysis, length of Onyx reflux along the microcatheter tip and utilization of a higher viscosity agent, Onyx 34, were significantly associated with tip detachment. Conclusion The use of the Apollo Microcatheter is both safe and effective during neurointerventional embolizations using Onyx. Leakage of liquid embolic agent from the detachment site is an infrequent technical complication that may be encountered with the device.

Crutches and children - proper fit and safety tips

MedlinePlus

... 000640.htm Crutches and children - proper fit and safety tips To use the sharing features on this ... the crutch, then extended when taking a step. Safety Tips Teach your child to: Always keep crutches ...

Tip cells: master regulators of tubulogenesis?

PubMed

Weavers, Helen; Skaer, Helen

2014-07-01

The normal development of an organ depends on the coordinated regulation of multiple cell activities. Focusing on tubulogenesis, we review the role of specialised cells or groups of cells that are selected from within tissue primordia and differentiate at the outgrowing tips or leading edge of developing tubules. Tip or leading cells develop distinctive patterns of gene expression that enable them to act both as sensors and transmitters of intercellular signalling. This enables them to explore the environment, respond to both tissue intrinsic signals and extrinsic cues from surrounding tissues and to regulate the behaviour of their neighbours, including the setting of cell fate, patterning cell division, inducing polarity and promoting cell movement and cell rearrangements by neighbour exchange. Tip cells are also able to transmit mechanical tension to promote tissue remodelling and, by interacting with the extracellular matrix, they can dictate migratory pathways and organ shape. Where separate tubular structures fuse to form networks, as in the airways of insects or the vascular system of vertebrates, specialised fusion tip cells act to interconnect disparate elements of the developing network. Finally, we consider their importance in the maturation of mature physiological function and in the development of disease. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Tips for Breastfeeding Moms

MedlinePlus

United States Department of Agriculture Tips for Breastfeeding Moms Making healthy food choices along with regular physical activity will keep you healthy while you breastfeed. Find Your Healthy Eating Style Choose ...

Development and testing of tip devices for horizontal axis wind turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gyatt, G.W.; Lissaman, P.B.S.

1985-05-01

A theoretical and field experimental program has been carried out to investigate the use of tip devices on horizontal axis wind turbine rotors. Objective was to improve performance by the reduction of tip losses. A vortex lattice computer model was used to optimize three basic tip configuration types for a 25 kW stall limited commercial wind turbines. The types were a change in tip planform, and a single-element and double-element nonplannar tip extension (winglets). Approximately 270 h of performance data were collected over a three-month period. The sampling interval was 2.4 s; thus over 400,000 raw data points were logged.more » Results for each of the three new tip devices, compared with the original tip, showed a small decrease (of the order of 1 kW) in power output over the measured range of wind speeds from cut-in at about 4 m/s to over 20 m/s, well into the stall limiting region. For aircraft wing tip devices, favorable tip shapes have been reported and it is likely that the tip devices tested in this program did not improve rotor performance because they were not optimally adjusted. The computer model used does not have adequate lifting surface resolution or accuracy to design these small winglet extensions.« less

Single-Molecule Chemistry with Surface- and Tip-Enhanced Raman Spectroscopy.

PubMed

Zrimsek, Alyssa B; Chiang, Naihao; Mattei, Michael; Zaleski, Stephanie; McAnally, Michael O; Chapman, Craig T; Henry, Anne-Isabelle; Schatz, George C; Van Duyne, Richard P

2017-06-14

Single-molecule (SM) surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS) have emerged as analytical techniques for characterizing molecular systems in nanoscale environments. SERS and TERS use plasmonically enhanced Raman scattering to characterize the chemical information on single molecules. Additionally, TERS can image single molecules with subnanometer spatial resolution. In this review, we cover the development and history of SERS and TERS, including the concept of SERS hot spots and the plasmonic nanostructures necessary for SM detection, the past and current methodologies for verifying SMSERS, and investigations into understanding the signal heterogeneities observed with SMSERS. Moving on to TERS, we cover tip fabrication and the physical origins of the subnanometer spatial resolution. Then, we highlight recent advances of SMSERS and TERS in fields such as electrochemistry, catalysis, and SM electronics, which all benefit from the vibrational characterization of single molecules. SMSERS and TERS provide new insights on molecular behavior that would otherwise be obscured in an ensemble-averaged measurement.

Updated Tax Tips for Forest Landowners for the 2010 Tax Year

Treesearch

Linda Wang; John L. Greene

2010-01-01

This bulletin is updated as of Dec. 20, 2010, to include the changes from Public Law 111-31 enacted on Dec. 17, 2010. It provides tax tips for woodland owners and their tax advisors in the preparation of the 2010 individual tax return. Please be aware the information presented here is not legal or accounting advice. Consult your legal and tax advisors for more complete...

Multipurpose fiber-optic sensor with sloped tip

NASA Astrophysics Data System (ADS)

Melnik, Ivan S.; Krivokhizha, A. M.; Ptashnik, O. V.

1991-08-01

Fiber-optic sensors C FOS) are wi. del y used for rioncontact measurements due to their simplicity, small size, insensitivity to I nfl uence of el ectromagneti C fiel ds , hi gh metrol ogi cal characteristics, etc. The operation principle of FOS with intensity modul ati on techni que I s based on the photodetector regi strati on of 1ight , reflected from the control 1 ed surface E I ) . The i ntensi ty of detected 1 1 ght depends on th FOS' s di stance from the control 1 ed surface, its form and inclination to sensor's axis, FOS shift speed, etc. So they can be consider multipurpose. We are devel opi ng FOS wi th i ntensi ty modul ati on techni que wi th traight tips as well as with sloped tips. In FOS with sloped tips the light ring spot is appearing on the controlled surface due to the effect of symmetry. We use thi s phenomena to empl oy refl ected 1 i ght more efficiently and to increase the FOS characteristics. Tak i ng I nto account the fact that pr obl ems of cal cul aWl on of fibers with sloped tip were not analyzed in details earlier-, in particular, only the case of light distribution of parallel beams runni ng was consi dered E 2) we wi I 1 conduct a consi stent cal cul ati on of bounds of i rradi ance fi ci d , created by a fi ber wi th sl oped tip, esti mate I i ght di stri buti on I n a 1 1 ght spot , and determi. ne characteristics of the FOS with sloped tip.

Development and testing of tip devices for horizontal axis wind turbines

NASA Technical Reports Server (NTRS)

Gyatt, G. W.; Lissaman, P. B. S.

1985-01-01

A theoretical and field experimental program has been carried out to investigate the use of tip devices on horizontal axis wind turbine rotors. The objective was to improve performance by the reduction of tip losses. While power output can always be increased by a simple radial tip extension, such a modification also results in an increased gale load both because of the extra projected area and longer moment arm. Tip devices have the potential to increase power output without such a structural penalty. A vortex lattice computer model was used to optimize three basic tip configuration types for a 25 kW stall limited commercial wind turbine. The types were a change in tip planform, and a single-element and double-element nonplanar tip extension (winglets). A complete data acquisition system was developed which recorded three wind speed components, ambient pressure, temperature, and turbine output. The system operated unattended and could perform real-time processing of the data, displaying the measured power curve as data accumulated in either a bin sort mode or polynomial curve fit. Approximately 270 hr of perormance data were collected over a three-month period. The sampling interval was 2.4 sec; thrus over 400,000 raw data points were logged. Results for each of the three new tip devices, compared with the original tip, showed a small decrease (of the order of 1 kW) in power output over the measured range of wind speeds from cut-in at about 4 m/s to over 20 m/s, well into the stall limiting region. Changes in orientation and angle-of-attack of the winglets were not made. For aircraft wing tip devices, favorable tip shapes have been reported and it is likely that the tip devices tested in this program did not improve rotor performance because they were not optimally adjusted.

7 CFR 29.3154 - Tips (T Group).

Code of Federal Regulations, 2013 CFR

2013-01-01

... stalk. (See Rule 12.) Grades Grade names and specifications T3F Good Tan Tips. Medium body, mature to..., mature, firm, wavy dull finish, weak color intensity, narrow, under 16″ in length, 80 percent uniform, and 20 percent injury tolerance. T5F Low Tan Tips. Medium body, mature, firm, wrinkly, dingy finish...

7 CFR 29.3154 - Tips (T Group).

Code of Federal Regulations, 2014 CFR

2014-01-01

... stalk. (See Rule 12.) Grades Grade names and specifications T3F Good Tan Tips. Medium body, mature to..., mature, firm, wavy dull finish, weak color intensity, narrow, under 16″ in length, 80 percent uniform, and 20 percent injury tolerance. T5F Low Tan Tips. Medium body, mature, firm, wrinkly, dingy finish...

7 CFR 29.3154 - Tips (T Group).

Code of Federal Regulations, 2012 CFR

2012-01-01

... stalk. (See Rule 12.) Grades Grade names and specifications T3F Good Tan Tips. Medium body, mature to..., mature, firm, wavy dull finish, weak color intensity, narrow, under 16″ in length, 80 percent uniform, and 20 percent injury tolerance. T5F Low Tan Tips. Medium body, mature, firm, wrinkly, dingy finish...

Back-to-School Health Tips: Exercise and Sleep

MedlinePlus

... up the same times each day. Keep room temperature on the cool side. A TV or computer in the bedroom can be a distraction. Read More "Back-to-School" Articles Health Tips: Immunizations / Health Tips: Exercise and ...

Modeling the Interaction between AFM Tips and Pinned Surface Nanobubbles.

PubMed

Guo, Zhenjiang; Liu, Yawei; Xiao, Qianxiang; Schönherr, Holger; Zhang, Xianren

2016-01-26

Although the morphology of surface nanobubbles has been studied widely with different AFM modes, AFM images may not reflect the real shapes of the nanobubbles due to AFM tip-nanobubble interactions. In addition, the interplay between surface nanobubble deformation and induced capillary force has not been well understood in this context. In our work we used constraint lattice density functional theory to investigate the interaction between AFM tips and pinned surface nanobubbles systematically, especially concentrating on the effects of tip hydrophilicity and shape. For a hydrophilic tip contacting a nanobubble, its hydrophilic nature facilitates its departure from the bubble surface, displaying a weak and intermediate-range attraction. However, when the tip squeezes the nanobubble during the approach process, the nanobubble shows an elastic effect that prevents the tip from penetrating the bubble, leading to a strong nanobubble deformation and repulsive interactions. On the contrary, a hydrophobic tip can easily pierce the vapor-liquid interface of the nanobubble during the approach process, leading to the disappearance of the repulsive force. In the retraction process, however, the adhesion between the tip and the nanobubble leads to a much stronger lengthening effect on nanobubble deformation and a strong long-range attractive force. The trends of force evolution from our simulations agree qualitatively well with recent experimental AFM observations. This favorable agreement demonstrates that our model catches the main intergradient of tip-nanobubble interactions for pinned surface nanobubbles and may therefore provide important insight into how to design minimally invasive AFM experiments.

Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan

An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE.more » The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)« less

Fabrication of silver tips for scanning tunneling microscope induced luminescence.

PubMed

Zhang, C; Gao, B; Chen, L G; Meng, Q S; Yang, H; Zhang, R; Tao, X; Gao, H Y; Liao, Y; Dong, Z C

2011-08-01

We describe a reliable fabrication procedure of silver tips for scanning tunneling microscope (STM) induced luminescence experiments. The tip was first etched electrochemically to yield a sharp cone shape using selected electrolyte solutions and then sputter cleaned in ultrahigh vacuum to remove surface oxidation. The tip status, in particular the tip induced plasmon mode and its emission intensity, can be further tuned through field emission and voltage pulse. The quality of silver tips thus fabricated not only offers atomically resolved STM imaging, but more importantly, also allows us to perform challenging "color" photon mapping with emission spectra taken at each pixel simultaneously during the STM scan under relatively small tunnel currents and relatively short exposure time.

Graded-index fiber tip optical tweezers: numerical simulation and trapping experiment.

PubMed

Gong, Yuan; Ye, Ai-Yan; Wu, Yu; Rao, Yun-Jiang; Yao, Yao; Xiao, Song

2013-07-01

Optical fiber tweezers based on a graded-index multimode fiber (GIMMF) tip is proposed. Light propagation characteristics and gradient force distribution near the GIMMF tip are numerically investigated, which are further compared with that of optical fiber tips based on conventional single mode fibers. The simulated results indicated that by selecting optimal GIMMF length, the gradient force of the GIMMF tip tweezers is about 4 times higher than that of the SMF tip tweezers with a same shape. To prove the feasibility of such a new concept, optical trapping of yeast cells with a diameter of ~5 μm using the chemically-etched GIMMF tip is experimentally demonstrated and the trapping force is also calculated.

Static biofilm removal around ultrasonic tips in vitro.

PubMed

Thurnheer, Thomas; Rohrer, Elodie; Belibasakis, Georgios N; Attin, Thomas; Schmidlin, Patrick R

2014-09-01

This study aims to investigate the biofilm removal capacity of two ultrasonic tips under standardized conditions using a multi-species biofilm model. Six-species biofilms were grown on hydroxyapatite discs for 64.5 h and were treated for 15 s with a standardized load of 40 g with a piezoelectric or magnetostrictive device. Tips were applied either with the tip end or with the side facing downwards. Detached bacteria were determined in the supernatant and colony-forming units (CFUs) counted after 72 h of incubation. Untreated specimens served as controls. Moreover, the biofilms remaining on the hydroxyapatite surface after treatment were stained using the Live/Dead stain, and the pattern of their detachment was assessed by confocal laser scanning microscopy (CLSM). As compared to the untreated control, it was found that only a side application of the magnetostrictive device was able to remove efficiently the biofilm. In contrast, its tip application as well as both applications of the piezoelectric device removed significantly less bacteria from the biofilm structure. These findings were corroborated by CLSM observation. Both ultrasonic tips under investigations led to bacterial detachment, but the action mode as well as the tip configuration and adaptation appeared to be influenced by the biofilm removal effectiveness. Biofilm removal remains a main goal of ultrasonic debridement. This should be reflected in respective laboratory investigations. The presented combination of methods applied on a multi-species biofilm model in vitro allows the evaluation of the effectiveness of different ultrasonic scaler applications.

Numerical simulation of tip vortices of wings in subsonic and transonic flows

NASA Technical Reports Server (NTRS)

Srinivasan, G. R.; Mccroskey, W. J.; Baeder, J. D.; Edwards, T. A.

1986-01-01

A multi block zonal algorithm which solves the thin-layer Navier-Stokes and the Euler equations is used to numerically simulate the formation and roll-up of the tip vortex in both subsonic and transonic flows. Four test cases which used small and large aspect ratio wings have been considered to examine the influence of the tip-cap shape, the tip planform and the free-stream Mach number. It appears that both the tip-planform and the tip-cap shape have some influence on the formation of the tip vortex, but its subsequent roll-up seems to be more influenced by the tip-planform shape. In general, a good definition of the formation and the roll-up of the tip vortex has been observed for all the cases considered here. Comparions of the numerical results with the limited, available experimental data show good agreement with both the surface pressures and the tip-vortex strength.

A Blade Tip Timing Method Based on a Microwave Sensor

PubMed Central

Zhang, Jilong; Duan, Fajie; Niu, Guangyue; Jiang, Jiajia; Li, Jie

2017-01-01

Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy. PMID:28492469

A Blade Tip Timing Method Based on a Microwave Sensor.

PubMed

Zhang, Jilong; Duan, Fajie; Niu, Guangyue; Jiang, Jiajia; Li, Jie

2017-05-11

Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy.

Propeller Tip Flutter

NASA Technical Reports Server (NTRS)

Liebers, Fritz

1932-01-01

The present report is limited to a case of tip flutter recognized by experience as being important. It is the case where outside interferences force vibrations upon the propeller. Such interferences may be set up by the engine, or they may be the result of an unsymmetrical field of flow.

Chemical Source Localization Fusing Concentration Information in the Presence of Chemical Background Noise.

PubMed

Pomareda, Víctor; Magrans, Rudys; Jiménez-Soto, Juan M; Martínez, Dani; Tresánchez, Marcel; Burgués, Javier; Palacín, Jordi; Marco, Santiago

2017-04-20

We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate. In addition, our algorithm allows multiple mobile gas sensors to be used. Ten realistic simulations and ten real data experiments are used for evaluation purposes. For the simulations, we have supposed that sensors are mounted on cars which do not have among its main tasks navigating toward the source. To collect the real dataset, a special arena with induced wind is built, and an autonomous vehicle equipped with several sensors, including a photo ionization detector (PID) for sensing chemical concentration, is used. Simulation results show that our algorithm, provides a better estimation of the source location even for a low background level that benefits the performance of binary version. The improvement is clear for the synthetic data while for real data the estimation is only slightly better, probably because our exploration arena is not able to provide uniform wind conditions. Finally, an estimation of the computational cost of the algorithmic proposal is presented.

Tips for labor coaches

MedlinePlus

... some tips for getting prepared. Before the big day Arrives Labor coaches should go to childbirth classes ... get through her labor and delivery. When the day Arrives You might be at the hospital for ...

Global Coastal Exposure due to Sea-level Rise beyond Tipping Points with Multiple Warming Pathways

NASA Astrophysics Data System (ADS)

Tawatari, R.; Iseri, Y.; Kiguchi, M.; Kanae, S.

2016-12-01

Sea-level is observed and estimated to continue rising. In the future, the rise could be abrupt and irreversible in century to millennial timescale even if we conduct strong reduction of greenhouse gas emission. Greenland ice sheet and West Antarctic ice sheet are considered as attributable climate systems which would significantly enhance presently-projected sea-level rise by several meters if global mean temperature passes certain "Tipping points" which would exist around +1-5 degree Celsius above present temperature (1980-1999 average). Therefore, vulnerable coastal low-lying area, especially small islands, deltas or poor developing countries, would suffer from semi-permanent inundation and forced to counteract due to the enhanced sea-level rise. This study estimate range of sea-level rise until the year 2300 and 3000 considering excess of tipping points with using multiple levels of temperature scenarios which consist of excess tipping points and non-excess tipping points pathways. We extract state-of-the-art knowledge of tipping elements from paper reviewing to express reasonable relationship between temperature and abruptly-changing sea-level transition across the ages. This study also calculate coastal exposure globally as affected population, area and asset below the estimated sea-level for each countries with overlaying 30 arc-second gridded topography, population distribution and the sea-level. The result indicates which country would be critically affected if we follow overshooting pathways. Furthermore, this study visualize uncertain coastal exposure due to sea-level rise in the future from the multiple warming pathways. This estimation of possible future beyond tipping point would be useful information for decision-makers to establish new planning of defense, migration or mitigation for the future societies.

Travel Tips Help IBS Sufferers Enjoy Their Vacations

MedlinePlus

... can feel more in control when traveling." IFFGD's travel tips include: Allow enough time in the morning to get to the airport ... Heartache 2004-0929 Norton Honored 2004-0525 IBS Travel Tips ... Real World 2001-1119 Heartburn or Heart Attack Commentary ...

A mathematical simulation of the tip-apex distance and the calcar-referenced tip-apex distance for intertrochanteric fractures reduced with lag screws.

PubMed

Li, Shuang; Chang, Shi-Min; Jin, Yan-Min; Zhang, Ying-Qi; Niu, Wen-Xin; Du, Shou-Chao; Zhang, Li-Zhi; Ma, Hui

2016-06-01

As a predictor of the risk of lag screw cutout, it was recommended that keeping tip-apex distance (TAD)<25mm and placing the screw centrally or inferiorly, but positioning the lag screw too inferiorly in the head would produce TAD>25mm. We aim to simulate various positions of the lag screw in the femoral head and identify whether 25mm is a suitable cut-off value that favours all sizes of femoral heads with intertrochanteric fractures of the hip. Using a general mathematical software, the positions of the screw tip points were simulated. The virtual anterior-posterior and lateral views were then visualised, and the locus of the screw tips was projected into a Cartesian coordinate system according to the TAD and calcar-referenced tip-apex distance (CalTAD) formulas. Each original virtual anterior-posterior and lateral image was zoomed and compiled to match a calculated average image. The screw tip points were recorded, traced and compiled into volumes which could be used to visualise the screw's movements and positioning within the femoral head. The extracted volumes were calculated when 10mmtip were then assessed. For the TAD calculation, the shape of the traced screw tip points had a pancake-like appearance, while the CalTAD plot produced a teardrop-shaped region. The volume ratios of TAD, CalTAD and overlapping region relative to the femoral head volume were respectively 3.51±1.30%, 5.19±1.62% and 2.64±1.32%. The volumes of the traced TAD, CalTAD and overlapping regions increased slower than the volume of an idealised sphere. Positioning the lag screw should address geometrical effects of both tip-apex distance and femoral head size, with an emphasis on measuring the position of the screw tip for the suitable zone by volume ratio. The previous 25mm TAD cut-off value should be adjusted according to the individual femoral head

Online monitoring of dynamic tip clearance of turbine blades in high temperature environments

NASA Astrophysics Data System (ADS)

Han, Yu; Zhong, Chong; Zhu, Xiaoliang; Zhe, Jiang

2018-04-01

Minimized tip clearance reduces the gas leakage over turbine blade tips and improves the thrust and efficiency of turbomachinery. An accurate tip clearance sensor, measuring the dynamic clearances between blade tips and the turbine case, is a critical component for tip clearance control. This paper presents a robust inductive tip clearance sensor capable of monitoring dynamic tip clearances of turbine machines in high-temperature environments and at high rotational speeds. The sensor can also self-sense the temperature at a blade tip in situ such that temperature effect on tip clearance measurement can be estimated and compensated. To evaluate the sensor’s performance, the sensor was tested for measuring the tip clearances of turbine blades under various working temperatures ranging from 700 K to 1300 K and at turbine rotational speeds ranging from 3000 to 10 000 rpm. The blade tip clearance was varied from 50 to 2000 µm. The experiment results proved that the sensor can accurately measure the blade tip clearances with a temporal resolution of 10 µm. The capability of accurately measuring the tip clearances at high temperatures (~1300 K) and high turbine rotation speeds (~30 000 rpm), along with its compact size, makes it promising for online monitoring and active control of blade tip clearances of high-temperature turbomachinery.

Backgrounds in Language.

ERIC Educational Resources Information Center

Maxwell, John C.; Long, Barbara K.

"Backgrounds in Language," a field-tested inservice course designed for use by groups of 15 or 25 language arts teachers, provides the subject matter background teachers need to make informed decisions about what curriculum materials to use in what way, at what time, and with which students. The course is comprised of eight 2-hour sessions,…

Information for Librarians and Trainers

MedlinePlus

... this page: https://medlineplus.gov/training/trainers.html Information for Librarians and Trainers To use the sharing ... Tips Resources for Teaching How to Find Health Information Online General Evaluating Internet Health Information: A Tutorial ...

The Case for Using Blunt-Tipped Lightning Rods as Strike Receptors.

NASA Astrophysics Data System (ADS)

Moore, C. B.; Aulich, G. D.; Rison, William

2003-07-01

Conventional lightning rods used in the United States have sharp tips, a practice derived from Benjamin Franklin's discovery of a means to obtain protection from lightning. However, the virtue of sharp tips for strike reception has never been established. An examination of the relevant physics shows that very strong electric fields are required above the tips of rods in order that they function as strike receptors but that the gradients of the field strength over sharp-tipped rods are so great that, at distances of a few millimeters, the local fields are often too weak for the development of upward-going streamers. In field tests, rods with rounded tips have been found to be better strike receptors than were nearby sharp-tipped rods.

Small-tip fast recovery imaging using non-slice-selective tailored tip-up pulses and RF-spoiling

PubMed Central

Nielsen, Jon-Fredrik; Yoon, Daehyun; Noll, Douglas C.

2012-01-01

Small-tip fast recovery (STFR) imaging is a new steady-state imaging sequence that is a potential alternative to balanced steady-state free precession (bSSFP). Under ideal imaging conditions, STFR may provide comparable signal-to-noise ratio (SNR) and image contrast as bSSFP, but without signal variations due to resonance offset. STFR relies on a tailored “tip-up”, or “fast recovery”, RF pulse to align the spins with the longitudinal axis after each data readout segment. The design of the tip-up pulse is based on the acquisition of a separate off-resonance (B0) map. Unfortunately, the design of fast (a few ms) slice- or slab-selective RF pulses that accurately tailor the excitation pattern to the local B0 inhomogeneity over the entire imaging volume remains a challenging and unsolved problem. We introduce a novel implementation of STFR imaging based on non-slice-selective tip-up pulses, which simplifies the RF design problem significantly. Out-of-slice magnetization pathways are suppressed using RF-spoiling. Brain images obtained with this technique show excellent gray/white matter contrast, and point to the possibility of rapid steady-state T2/T1-weighted imaging with intrinsic suppression of cerebrospinal fluid, through-plane vessel signal, and off-resonance artifacts. In the future we expect STFR imaging to benefit significantly from parallel excitation hardware and high-order gradient shim systems. PMID:22511367

Identification of tipping elements of the Indian Summer Monsoon using climate network approach

NASA Astrophysics Data System (ADS)

Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

2015-04-01

Spatial and temporal variability of the rainfall is a vital question for more than one billion of people inhabiting the Indian subcontinent. Indian Summer Monsoon (ISM) rainfall is crucial for India's economy, social welfare, and environment and large efforts are being put into predicting the Indian Summer Monsoon. For predictability of the ISM, it is crucial to identify tipping elements - regions over the Indian subcontinent which play a key role in the spatial organization of the Indian monsoon system. Here, we use climate network approach for identification of such tipping elements of the ISM. First, we build climate networks of the extreme rainfall, surface air temperature and pressure over the Indian subcontinent for pre-monsoon, monsoon and post-monsoon seasons. We construct network of extreme rainfall event using observational satellite data from 1998 to 2012 from the Tropical Rainfall Measuring Mission (TRMM 3B42V7) and reanalysis gridded daily rainfall data for a time period of 57 years (1951-2007) (Asian Precipitation Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources, APHRODITE). For the network of surface air temperature and pressure fields, we use re-analysis data provided by the National Center for Environmental Prediction and National Center for Atmospheric Research (NCEP/NCAR). Second, we filter out data by coarse-graining the network through network measures, and identify tipping regions of the ISM. Finally, we compare obtained results of the network analysis with surface wind fields and show that occurrence of the tipping elements is mostly caused by monsoonal wind circulation, migration of the Intertropical Convergence Zone (ITCZ) and Westerlies. We conclude that climate network approach enables to select the most informative regions for the ISM, providing realistic description of the ISM dynamics with fewer data, and also help to identify tipping regions of the ISM. Obtained tipping elements deserve a

Twelve tips for overnight teaching.

PubMed

Richards, Jeremy B; Wilcox, Susan R; Roberts, David H; Schwartzstein, Richard M

2014-03-01

The European Working Time Directive and the United States' duty hour restrictions have changed resident physicians' schedules, specifically increasing overnight shifts and decreasing overall time spent in the hospital. As residents' perception of night shifts is that they have little educational value, efforts to improve educational opportunities and night attending teaching are desirable. However, resources about and recommendations for best practices for overnight teaching by faculty are scarce. To provide 12 tips to highlight strategies intended to optimize attending physicians' overnight teaching skills and strategies. The tips provided are based on our experiences and reflections as in-house faculty supervising residents working overnight, by our experience and group discussions as medical educators, and the available literature. The 12 tips presented offer specific strategies to optimize attending physicians' overnight teaching for resident physicians, specifically highlighting the unique logistics, pedagogy and follow-up of overnight teaching. Preparation for teaching is important in any environment, but understanding the unique timing and circumstances associated with overnight teaching is vital to ensure that overnight teaching is effective. Acknowledging and addressing the physical and cognitive obstacles associated with overnight teaching and learning is necessary to maximize the educational value of overnight teaching.

Pinning effects from substrate and AFM tip surfaces on interfacial nanobubbles

NASA Astrophysics Data System (ADS)

Teshima, Hideaki; Takahashi, Koji; Takata, Yasuyuki; Nishiyama, Takashi

2017-11-01

Measurement accuracy of atomic force microscopy (AFM) is vital to understand the mechanism of interfacial nanobubbles. In this study, we report the influence of pinning derived from both substrate and AFM tip surfaces on the measured shape of interfacial nanobubbles in peak force tapping mode. First, we pushed the nanobubbles using the AFM tip with high peak force setpoint. As a result, the deformed nanobubbles kept their flat shape for several tens of minutes. We quantitatively discuss the pinning force from substrate surface, which retains the flat shape enhancing the stability of nanobubbles. Next, we prepared three AFM tips with different wettability and measured the nanobubbles with an identical setpoint. By comparing the force curves obtained during the measurements, it seems that the (middle-)hydrophobic tips penetrated the liquid/gas interface and received repulsive force resulting from positive meniscus formed by pinning at the tip surface. In contrast, hydrophilic tip didn't penetrate the interface and received the force from the deformation of the interface of the nanobubbles. In addition, the measurements using the (middle-)hydrophobic tips led to the underestimation of the nanobubbles profile corresponding to the pinning position at the tip surfaces.

Restaurant Dining: Seven Tips for Staying Gluten Free

MedlinePlus

GiG Education Bulletin Restaurant Dining: Seven Tips for Staying Gluten-Free Updated May 2014 Tips for Dining Away from Home 1. Selection of eating establishment. • Your success at gluten-free dining will be determined by a number of factors, including the ...

Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Andrew; Butte, Manish J., E-mail: manish.butte@stanford.edu

2014-08-04

We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, andmore » results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished.« less

Filter presence and tipping paper color influence consumer perceptions of cigarettes.

PubMed

O'Connor, Richard J; Bansal-Travers, Maansi; Cummings, K Michael; Hammond, David; Thrasher, James F; Tworek, Cindy

2015-12-22

Cigarettes are marketed in a wide array of packaging and product configurations, and these may impact consumers' perceptions of product health effects and attractiveness. Filtered cigarettes are typically perceived as less hazardous and white tipping paper (as opposed to cork) often conveys 'lightness'. This study examined cigarette-related perceptions among 1220 young adult (age 18-35) current, ever, and never smokers recruited from three eastern U.S. cities (Buffalo NY, Columbia SC, Morgantown WV). Participants rated three cigarette sticks: two filtered cigarettes 85 mm in length, differing only in tipping paper color (cork versus white), and an unfiltered 70 mm cigarette. Overall, the cork-tipped cigarette was most commonly selected on taste and attractiveness, the white-tipped on least dangerous, and the unfiltered on most dangerous. Current smokers were more likely to select white-tipped (OR = 1.98) and cork-tipped (OR = 3.42) cigarettes, while ever smokers more commonly selected the cork-tipped (OR = 1.96), as most willing to try over the other products. Those willing to try the filtered white-tipped cigarette were more likely to have rated that cigarette as best tasting (OR = 11.10), attracting attention (OR = 17.91), and lowest health risk (OR = 1.94). Similarly, those willing to try cork tipped or unfiltered cigarettes rated those as best testing, attracting attention, and lowest health risk, respectively. Findings from this study demonstrate that consumer product perceptions can be influenced by elements of cigarette design, such as the presence and color of the filter tip.

Lifeact-mEGFP Reveals a Dynamic Apical F-Actin Network in Tip Growing Plant Cells

PubMed Central

Hepler, Peter K.; Bezanilla, Magdalena

2009-01-01

Background Actin is essential for tip growth in plants. However, imaging actin in live plant cells has heretofore presented challenges. In previous studies, fluorescent probes derived from actin-binding proteins often alter growth, cause actin bundling and fail to resolve actin microfilaments. Methodology/Principal Findings In this report we use Lifeact-mEGFP, an actin probe that does not affect the dynamics of actin, to visualize actin in the moss Physcomitrella patens and pollen tubes from Lilium formosanum and Nicotiana tobaccum. Lifeact-mEGFP robustly labels actin microfilaments, particularly in the apex, in both moss protonemata and pollen tubes. Lifeact-mEGFP also labels filamentous actin structures in other moss cell types, including cells of the gametophore. Conclusions/Significance Lifeact-mEGFP, when expressed at optimal levels does not alter moss protonemal or pollen tube growth. We suggest that Lifeact-mEGFP represents an exciting new versatile probe for further studies of actin's role in tip growing plant cells. PMID:19478943

Tip Vortices of Isolated Wings and Helicopter Rotor Blades.

DTIC Science & Technology

1987-12-01

root to tip, as expected due to the induced downwash of the tip vor- tex and wake vortex sheet. Although the three different tip-caps produce very...the inherent limitation of not being able to model the vortex wake with these equations, although the Euler formulation has in it the necessary...physics to model vorticity transport correctly. These equations basically lack the physical mecha- nism needed to generate the vortex wake . However, in

Lighting: Traffic Safety Tips

DOT National Transportation Integrated Search

1996-01-01

This fact sheet, NHTSA Facts: Summer 1996, discusses traffic safety tips on motor vehicle lighting, including headlights, tail lights, and signal lights. It details the cleaning of headlamps, proper aiming of headlamps, and replacement of burned out ...

Measurements of Supersonic Wing Tip Vortices

NASA Technical Reports Server (NTRS)

Smart, Michael K.; Kalkhoran, Iraj M.; Benston, James

1994-01-01

An experimental survey of supersonic wing tip vortices has been conducted at Mach 2.5 using small performed 2.25 chords down-stream of a semi-span rectangular wing at angle of attack of 5 and 10 degrees. The main objective of the experiments was to determine the Mach number, flow angularity and total pressure distribution in the core region of supersonic wing tip vortices. A secondary aim was to demonstrate the feasibility of using cone probes calibrated with a numerical flow solver to measure flow characteristics at supersonic speeds. Results showed that the numerically generated calibration curves can be used for 4-hole cone probes, but were not sufficiently accurate for conventional 5-hole probes due to nose bluntness effects. Combination of 4-hole cone probe measurements with independent pitot pressure measurements indicated a significant Mach number and total pressure deficit in the core regions of supersonic wing tip vortices, combined with an asymmetric 'Burger like' swirl distribution.

Eddy current probe with foil sensor mounted on flexible probe tip and method of use

DOEpatents

Viertl, John R. M.; Lee, Martin K.

2001-01-01

A pair of copper coils are embedded in the foil strip. A first coil of the pair generates an electromagnetic field that induces eddy currents on the surface, and the second coil carries a current influenced by the eddy currents on the surface. The currents in the second coil are analyzed to obtain information on the surface eddy currents. An eddy current probe has a metal housing having a tip that is covered by a flexible conductive foil strip. The foil strip is mounted on a deformable nose at the probe tip so that the strip and coils will conform to the surface to which they are applied.

Homogeneous nucleation of water in argon. Nucleation rate computation from molecular simulations of TIP4P and TIP4P/2005 water model.

PubMed

Dumitrescu, Lucia R; Smeulders, David M J; Dam, Jacques A M; Gaastra-Nedea, Silvia V

2017-02-28

Molecular dynamics (MD) simulations were conducted to study nucleation of water at 350 K in argon using TIP4P and TIP4P/2005 water models. We found that the stability of any cluster, even if large, strongly depends on the energetic interactions with its vicinity, while the stable clusters change their composition almost entirely during nucleation. Using the threshold method, direct nucleation rates are obtained. Our nucleation rates are found to be 1.08×10 27 cm -3 s -1 for TIP4P and 2.30×10 27 cm -3 s -1 for TIP4P/2005. The latter model prescribes a faster dynamics than the former, with a nucleation rate two times larger due to its higher electrostatic charges. The non-equilibrium water densities derived from simulations and state-of-art equilibrium parameters from Vega and de Miguel [J. Chem. Phys. 126, 154707 (2007)] are used for the classical nucleation theory (CNT) prediction. The CNT overestimates our results for both water models, where TIP4P/2005 shows largest discrepancy. Our results complement earlier data at high nucleation rates and supersaturations in the Hale plot [Phys. Rev. A 33, 4156 (1986)], and are consistent with MD data on the SPC/E and the TIP4P/2005 model.

Electron Transfer from Triplet State of TIPS-Pentacene Generated by Singlet Fission Processes to CH3NH3PbI3 Perovskite.

PubMed

Lee, Sangsu; Hwang, Daesub; Jung, Seok Il; Kim, Dongho

2017-02-16

To reveal the applicability of singlet fission processes in perovskite solar cell, we investigated electron transfer from TIPS-pentacene to CH 3 NH 3 PbI 3 (MAPbI 3 ) perovskite in film phase. Through the observation of the shorter fluorescence lifetime in TIPS-pentacene/MAPbI 3 perovskite bilayer film (5 ns) compared with pristine MAPbI 3 perovskite film (20 ns), we verified electron-transfer processes between TIPS-pentacene and MAPbI 3 perovskite. Furthermore, the observation of singlet fission processes, a faster decay rate, TIPS-pentacene cations, and the analysis of kinetic profiles of the intensity ratio between 500 and 525 nm in the TA spectra of the TIPS-pentacene/MAPbI 3 perovskite bilayer film indicate that electron transfer occurs from triplet state of TIPS-pentacene generated by singlet fission processes to MAPbI 3 perovskite conduction band. We believe that our results can provide useful information on the design of solar cells sensitized by singlet fission processes and pave the way for new types of perovskite solar cells.

Alar setback technique: a controlled method of nasal tip deprojection.

PubMed

Foda, H M

2001-11-01

To describe an alar cartilage-modifying technique aimed at decreasing nasal tip projection in cases with overdeveloped alar cartilages and to compare it with other deprojection techniques used to correct such deformity. Selected case series. University and private practice settings in Alexandria, Egypt. Twenty patients presenting for rhinoplasty who had overprojected nasal tips primarily due to overdeveloped alar cartilages. All cases were primary cases except for one patient, who had undergone 2 previous rhinoplasties. An external rhinoplasty approach was used to set back the alar cartilages by shortening their medial and lateral crura. The choice of performing a high or low setback depended on the preexisting lobule-to-columella ratio. Following the setback, the alar cartilages were reconstructed in a fashion that increased the strength and stability of the tip complex. Subjective evaluation included clinical examination, analysis of preoperative and postoperative photographs, and patient satisfaction. Objective evaluation of nasal tip projection, using the Goode ratio and the nasofacial angle, was performed preoperatively and repeated at least 6 months postoperatively. A low setback was performed in 16 cases (80%) and a high setback in 4 (20%). The mean follow-up period was 18 months (range, 6-36 months). The technique effectively deprojected the nasal tip as evidenced by the considerable postoperative decrease in values of the Goode ratio and the nasofacial angle. No complications were encountered and no revision surgical procedures were required. The alar setback technique has many advantages; it results in precise predictable amounts of deprojection, controls the degree of tip rotation, preserves the natural contour of the nasal tip, respects the tip support mechanisms, increases the strength and stability of nasal tip complex, preserves or restores the normal lobule-to-columella proportion, and does not lead to alar flaring. However, the technique requires

Web-Based Tailored Intervention for Preparation of Parents and Children for Outpatient Surgery (WebTIPS): Formative Evaluation and Randomized Controlled Trial

PubMed Central

Fortier, Michelle A.; Bunzli, Elizabeth; Walthall, Jessica; Olshansky, Ellen; Saadat, Haleh; Santistevan, Ricci; Mayes, Linda; Kain, Zeev N.

2015-01-01

Background The purpose of this two-phase project was to conduct formative evaluation and test the preliminary efficacy of a newly developed web-based, tailored behavioral preparation program (WebTIPS) for children undergoing outpatient surgery and their parents Methods Phase I enrolled 13 children aged 2–7 years undergoing outpatient elective surgery and their parents for formative evaluation of WebTIPS. Parent participation focus groups which are common in qualitative research and are a method of asking research participants about their perceptions and attitudes regarding a product or concept. In phase II, children age 2–7 years in two medical centers were randomly assigned to receive the WebTIPS program (n = 38) compared to children receiving standard of care (n = 44). The primary outcome of phase II was child and parent preoperative anxiety. Results In phase I, parents reported WebTIPS to be both helpful (p < 0.001) and easy to use (p < 0.001). In phase II, children in the WebTIPS group (36.2 ± 14.1) were less anxious than children in the standard of care group (46.0 ± 19.0) at entrance to the operating room (p = 0.02; Cohen’s d = 0.59) and introduction of the anesthesia mask (43.5 ± 21.7 vs. 57.0 ± 21.2, respectively, p = 0.01; Cohen’s d = 0.63). Parents in the WebTIPS group (32.1 ± 7.4) also experienced less anxiety compared to parents in the control group (36.8 ± 7.1) in the preoperative holding area (p = 0.004; Cohen’s d = 0.65). Conclusions WebTIPS was well received by parents and children and led to reductions in preoperative anxiety. PMID:25790213

Experiences with nutrition-related information during antenatal care of pregnant women of different ethnic backgrounds residing in the area of Oslo, Norway.

PubMed

Garnweidner, Lisa M; Sverre Pettersen, Kjell; Mosdøl, Annhild

2013-12-01

to explore experiences with nutrition-related information during routine antenatal care among women of different ethnical backgrounds. individual interviews with seventeen participants were conducted twice during pregnancy. Data collection and analysis were inspired by an interpretative phenomenological approach. participants were purposively recruited at eight Mother and Child Health Centres in the area of Oslo, Norway, where they received antenatal care. participants had either immigrant backgrounds from African and Asian countries (n=12) or were ethnic Norwegian (n=5). Participants were pregnant with their first child and had a pre-pregnancy Body Mass Index above 25 kg/m(2). participants experienced that they were provided with little nutrition-related information in antenatal care. The information was perceived as presented in very general terms and focused on food safety. Weight management and the long-term prevention of diet-related chronic diseases had hardly been discussed. Participants with immigrant backgrounds appeared to be confused about information given by the midwife which was incongruent with their original food culture. The participants were actively seeking for nutrition-related information and had to navigate between various sources of information. the midwife is considered a trustworthy source of nutrition-related information. Therefore, antenatal care may have considerable potential to promote a healthy diet to pregnant women. Findings suggest that nutrition communication in antenatal care should be more tailored towards women's dietary habits and cultural background, nutritional knowledge as well as level of nutrition literacy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Twelve tips for "flipping" the classroom.

PubMed

Moffett, Jennifer

2015-04-01

The flipped classroom is a pedagogical model in which the typical lecture and homework elements of a course are reversed. The following tips outline the steps involved in making a successful transition to a flipped classroom approach. The tips are based on the available literature alongside the author's experience of using the approach in a medical education setting. Flipping a classroom has a number of potential benefits, for example increased educator-student interaction, but must be planned and implemented carefully to support effective learning.

21 CFR 870.2870 - Catheter tip pressure transducer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter tip pressure transducer. 870.2870 Section 870.2870 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2870 Catheter tip...

Aerodynamic effect of a honeycomb rotor tip shroud on a 50.8-centimeter-tip-diameter core turbine

NASA Technical Reports Server (NTRS)

Moffitt, T. P.; Whitney, W. J.

1983-01-01

A 50.8-cm-tip-diameter turbine equipped with a rotor tip shroud of hexagonal cell (or honeycomb) cross section has been tested in warm air (416 K) for a range of shroud coolant to primary flow rates. Test results were also obtained for the same turbine operated with a solid shroud for comparison. The results showed that the combined effect of the honeycomb shroud and the coolant flow was to cause a reduction of 2.8 points in efficiency at design speed, pressure ratio, and coolant flow rate. With the coolant system inactivated, the honeycomb shroud caused a decrease in efficiency of 2.3 points. These results and those obtained from a small reference turbine indicate that the dominant factor governing honeycomb tip shroud loss is the ratio of honeycomb depth to blade span. The loss results of the two shrouds could be correlated on this basis. The same honeycomb and coolant effects are expected to occur for the hot (2200 K) version of this turbine.

Technology Tips: A Potpourri.

ERIC Educational Resources Information Center

Cuoco, Albert A.; And Others, Eds.

1994-01-01

Contains tips from readers about using technology in the classroom, including notebook computers, classroom sets of calculators, geometry software, LOGO software, publisher discounts, curriculum materials in CD-ROM, and volunteer help in computers and computer networking for schools. (MKR)

Tip-Enhanced Photoinduced Electron Transfer and Ionization on Vertical Silicon Nanowires.

PubMed

Chen, Xiaoming; Wang, Tao; Lin, Leimiao; Wo, Fangjie; Liu, Yaqin; Liang, Xiao; Ye, Hui; Wu, Jianmin

2018-05-02

Nanostructured semiconductors are one of the most potent candidates for matrix-free laser desorption/ionization mass spectrometric (LDI-MS) analysis of low-molecular-weight molecules. Herein, the enhanced photoinduced electron transfer and LDI on the tip of a vertical silicon nanowire (SiNW) array were investigated. Theoretical simulation and LDI detection of indigo and isatin molecules in negative ion mode revealed that the electric field can be enhanced on the tip end of SiNWs, thereby promoting the energy and electron transfer to the analytes adsorbed on the tip of SiNWs. On the basis of this finding, a tip-contact sampling method coupled with LDI-MS detection was established. In this strategy, the tip of SiNWs can be regarded as microextraction heads for the sampling of molecules when they come in contact with analytes. Impression of skin, tissue, and pericarp on the vertical SiNW array can effectively transfer endogenous metabolites or exogenous substances onto the tip. Upon laser irradiation, the adsorbed molecules on the SiNW tip can be efficiently ionized and detected in negative ion mode because of the tip-enhanced electron transfer and LDI effect. We believe this work may significantly expand the application of LDI-MS in various fields.

A numerical study of crack tip constraint in ductile single crystals

NASA Astrophysics Data System (ADS)

Patil, Swapnil D.; Narasimhan, R.; Mishra, R. K.

In this work, the effect of crack tip constraint on near-tip stress and deformation fields in a ductile FCC single crystal is studied under mode I, plane strain conditions. To this end, modified boundary layer simulations within crystal plasticity framework are performed, neglecting elastic anisotropy. The first and second terms of the isotropic elastic crack tip field, which are governed by the stress intensity factor K and T-stress, are prescribed as remote boundary conditions and solutions pertaining to different levels of T-stress are generated. It is found that the near-tip deformation field, especially, the development of kink or slip shear bands, is sensitive to the constraint level. The stress distribution and the size and shape of the plastic zone near the crack tip are also strongly influenced by the level of T-stress, with progressive loss of crack tip constraint occurring as T-stress becomes more negative. A family of near-tip fields is obtained which are characterized by two terms (such as K and T or J and a constraint parameter Q) as in isotropic plastic solids.

Advanced ceramic material for high temperature turbine tip seals

NASA Technical Reports Server (NTRS)

Solomon, N. G.; Vogan, J. W.

1978-01-01

Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

Sharpening of field emitter tips using high-energy ions

DOEpatents

Musket, Ronald G.

1999-11-30

A process for sharpening arrays of field emitter tips of field emission cathodes, such as found in field-emission, flat-panel video displays. The process uses sputtering by high-energy (more than 30 keV) ions incident along or near the longitudinal axis of the field emitter to sharpen the emitter with a taper from the tip or top of the emitter down to the shank of the emitter. The process is particularly applicable to sharpening tips of emitters having cylindrical or similar (e.g., pyramidal) symmetry. The process will sharpen tips down to radii of less than 12 nm with an included angle of about 20 degrees. Because the ions are incident along or near the longitudinal axis of each emitter, the tips of gated arrays can be sharpened by high-energy ion beams rastered over the arrays using standard ion implantation equipment. While the process is particularly applicable for sharpening of arrays of field emitters in field-emission flat-panel displays, it can be effectively utilized in the fabrication of other vacuum microelectronic devices that rely on field emission of electrons.

Corrugated metal-coated tapered tip for scanning near-field optical microscope.

PubMed

Antosiewicz, Tomasz J; Szoplik, Tomasz

2007-08-20

This paper addresses an important issue of light throughput of a metal-coated tapered tip for scanning near-field microscope (SNOM). Corrugations of the interface between the fiber core and metal coating in the form of parallel grooves of different profiles etched in the core considerably increase the energy throughput. In 2D FDTD simulations in the Cartesian coordinates we calculate near-field light emitted from such tips. For a certain wavelength range total intensity of forward emission from the corrugated tip is 10 times stronger than that from a classical tapered tip. When realized in practice the idea of corrugated tip may lead up to twice better resolution of SNOM.

Identifying passivated dynamic force microscopy tips on H:Si(100)

NASA Astrophysics Data System (ADS)

Sharp, Peter; Jarvis, Sam; Woolley, Richard; Sweetman, Adam; Kantorovich, Lev; Pakes, Chris; Moriarty, Philip

2012-06-01

The chemical reactivity of the tip plays a central role in image formation in dynamic force microscopy, but in very many cases the state of the probe is a key experimental unknown. We show here that an H-terminated and thus chemically unreactive tip can be readily identified via characteristic imaging and spectroscopic (F(z)) signatures, including, in particular, contrast inversion, on hydrogen-passivated Si(100). We determine the tip apex termination by comparing site-specific difference force curves with the results of density functional theory, providing a clear protocol for the identification of chemically unreactive tips on silicon surfaces.

Sound from a Two-Blade Propeller at Supersonic Tip Speeds

NASA Technical Reports Server (NTRS)

Hubbard, Harvey H; Lassiter, Leslie W

1952-01-01

Report presents the results of sound measurements at static conditions made for a two-blade 47-inch-diameter propeller in the tip Mach number range 0.75 to 1.30. For comparison, spectrums have been obtained at both subsonic and supersonic tip speeds. In addition, the measured data are compared with calculations by the theory of Gutin which has previously been found adequate for predicting the sound at subsonic tip speeds. Curves are presented from which the maximum over-all noise levels in free space may be estimated if the power, tip Mach number, and distance are known.

Tipping elements in the Arctic marine ecosystem.

PubMed

Duarte, Carlos M; Agustí, Susana; Wassmann, Paul; Arrieta, Jesús M; Alcaraz, Miquel; Coello, Alexandra; Marbà, Núria; Hendriks, Iris E; Holding, Johnna; García-Zarandona, Iñigo; Kritzberg, Emma; Vaqué, Dolors

2012-02-01

The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

Sports Dehydration Safety Tips

MedlinePlus

Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

Brakes: Traffic Safety Tips

DOT National Transportation Integrated Search

1996-01-01

This fact sheet, NHTSA Facts: Summer 1996, describes traffic safety tips about brakes. It discusses drum brakes, disc brakes, and antilock braking systsms. It notes that there are government standards for brakes, and describes how to take care of bra...

Defining tipping points for social-ecological systems scholarship—an interdisciplinary literature review

NASA Astrophysics Data System (ADS)

Milkoreit, Manjana; Hodbod, Jennifer; Baggio, Jacopo; Benessaiah, Karina; Calderón-Contreras, Rafael; Donges, Jonathan F.; Mathias, Jean-Denis; Rocha, Juan Carlos; Schoon, Michael; Werners, Saskia E.

2018-03-01

The term tipping point has experienced explosive popularity across multiple disciplines over the last decade. Research on social-ecological systems (SES) has contributed to the growth and diversity of the term’s use. The diverse uses of the term obscure potential differences between tipping behavior in natural and social systems, and issues of causality across natural and social system components in SES. This paper aims to create the foundation for a discussion within the SES research community about the appropriate use of the term tipping point, especially the relatively novel term ‘social tipping point.’ We review existing literature on tipping points and similar concepts (e.g. regime shifts, critical transitions) across all spheres of science published between 1960 and 2016 with a special focus on a recent and still small body of work on social tipping points. We combine quantitative and qualitative analyses in a bibliometric approach, rooted in an expert elicitation process. We find that the term tipping point became popular after the year 2000—long after the terms regime shift and critical transition—across all spheres of science. We identify 23 distinct features of tipping point definitions and their prevalence across disciplines, but find no clear taxonomy of discipline-specific definitions. Building on the most frequently used features, we propose definitions for tipping points in general and social tipping points in SES in particular.

Anisotropic adhesion properties of triangular-tip-shaped micropillars.

PubMed

Kwak, Moon Kyu; Jeong, Hoon Eui; Bae, Won Gyu; Jung, Ho-Sup; Suh, Kahp Y

2011-08-22

Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

21 CFR 870.2870 - Catheter tip pressure transducer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment for... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into...

21 CFR 870.2870 - Catheter tip pressure transducer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment for... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into...

21 CFR 870.2870 - Catheter tip pressure transducer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment for... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into...

21 CFR 870.2870 - Catheter tip pressure transducer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment for... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into...

Ultrafast time-resolved photoemission of a metallic tip/substrate junction

NASA Astrophysics Data System (ADS)

Meng, Xiang; Jin, Wencan; Yang, Hao; Dadap, Jerry; Osgood, Richard; Camillone, Nicholas, III

The strong near-field enhancement of metallic-tip nanostructures has attracted great interest in scanning microscopy techniques, such as surface-enhanced Raman scattering, near-field scanning optical microscopy and tip-enhanced nonlinear imaging. In this talk, we use a full vectorial 3D-FDTD method to investigate the spatial characteristics of the optical field confinement and localization between a tungsten nanoprobe and an infinite planar silver substrate, with two-color ultrafast laser excitation scheme. The degree of two-color excited field enhancement, geometry dependence, the exact mechanism of optical tip-substrate coupling and tip-substrate plasmon resonances are significant in understanding the electrodynamical responses at tip-substrate junction. The demonstrated measurements with subpicosecond time and subnanometer spatial resolution suggest a new approach to ultrafast time-resolved measurements of surface electron dynamics. DE-FG 02-90-ER-14104; DE-FG 02-04-ER-46157.

Flowfield and heat transfer past an unshrouded gas turbine blade tip with different shapes

NASA Astrophysics Data System (ADS)

Liu, Jian-Jun; Li, Peng; Zhang, Chao; An, Bai-Tao

2013-04-01

This paper describes the numerical investigations of flow and heat transfer in an unshrouded turbine rotor blade of a heavy duty gas turbine with four tip configurations. By comparing the calculated contours of heat transfer coefficients on the flat tip of the HP turbine rotor blade in the GE-E3 aircraft engine with the corresponding experimental data, the κ-ω turbulence model was chosen for the present numerical simulations. The inlet and outlet boundary conditions for the turbine rotor blade are specified as the real gas turbine, which were obtained from the 3D full stage simulations. The rotor blade and the hub endwall are rotary and the casing is stationary. The influences of tip configurations on the tip leakage flow and blade tip heat transfer were discussed. It's showed that the different tip configurations changed the leakage flow patterns and the pressure distributions on the suction surface near the blade tip. Compared with the flat tip, the total pressure loss caused by the leakage flow was decreased for the full squealer tip and pressure side squealer tip, while increased for the suction side squealer tip. The suction side squealer tip results in the lowest averaged heat transfer coefficient on the blade tip compared to the other tip configurations.

[Effective communication with talkative patients: 10 tips].

PubMed

Giroldi, Esther; Veldhuijzen, Wemke; Bareman, Frits; Bueving, Herman; van der Weijden, Trudy; van der Vleuten, Cees; Muris, Jean

2016-01-01

Consultations with talkative patients present a challenge to doctors. It is difficult to gather all the necessary information within the available time, without damaging the doctor-patient relationship. Based on the listed existing literature and doctors' experiences, we present ten tips for gathering information from talkative patients in an effective manner whilst maintaining a good therapeutic alliance. In consultations with talkative patients, it is important to explore the cause of patients' talkativeness and to adapt one's communication approach accordingly.- Familiar communication strategies such as 'summarizing' can still be applied. When taking this route, a more directive communication approach--e.g. by means of a 'closed-ended summary'--can prevent the patient interrupting the doctor or departing from his subject. There are strategies aimed at avoiding a damaging effect to the doctor-patient relationship when applying this approach: don't be overly directive, make the patient co-responsible for efficient time management in the consultation, and make use of empathic interrupting and humour.

Numerical investigation of tip clearance effects on the performance of ducted propeller

NASA Astrophysics Data System (ADS)

Ding, Yongle; Song, Baowei; Wang, Peng

2015-09-01

Tip clearance loss is a limitation of the improvement of turbomachine performance. Previous studies show the Tip clearance loss is generated by the leakage flow through the tip clearance, and is roughly linearly proportional to the gap size. This study investigates the tip clearance effects on the performance of ducted propeller. The investigation was carried out by solving the Navier-Stokes equations with the commercial Computational Fluid Dynamic (CFD) code CFX14.5. These simulations were carried out to determine the underlying mechanisms of the tip clearance effects. The calculations were performed at three different chosen advance ratios. Simulation results showed that the tip loss slope was not linearly at high advance due to the reversed pressure at the leading edge. Three type of vortical structures were observed in the tip clearance at different clearance size.

Novel fiber optic tip designs and devices for laser surgery

NASA Astrophysics Data System (ADS)

Hutchens, Thomas Clifton

Fiber optic delivery of laser energy has been used for years in various types of surgical procedures in the human body. Optical energy provides several benefits over electrical or mechanical surgery, including the ability to selectively target specific tissue types while preserving others. Specialty fiber optic tips have also been introduced to further customize delivery of laser energy to the tissue. Recent evolution in lasers and miniaturization has opened up opportunities for many novel surgical techniques. Currently, ophthalmic surgeons use relatively invasive mechanical tools to dissect retinal deposits which occur in proliferative diabetic retinopathy. By using the tight focusing properties of microspheres combined with the short optical penetration depth of the Erbium:YAG laser and mid-IR fiber delivery, a precise laser scalpel can be constructed as an alternative, less invasive and more precise approach to this surgery. Chains of microspheres may allow for a self limiting ablation depth of approximately 10 microm based on the defocusing of paraxial rays. The microsphere laser scalpel may also be integrated with other surgical instruments to reduce the total number of handpieces for the surgeon. In current clinical laser lithotripsy procedures, poor input coupling of the Holmium:YAG laser energy frequently damages and requires discarding of the optical fiber. However, recent stone ablation studies with the Thulium fiber laser have provided comparable results to the Ho:YAG laser. The improved spatial beam profile of the Thulium fiber laser can also be efficiently coupled into a fiber approximately one third the diameter and reduces the risk of damaging the fiber input. For this reason, the trunk optical fiber minus the distal fiber tip can be preserved between procedures. The distal fiber tip, which degrades during stone ablation, could be made detachable and disposable. A novel, low-profile, twist-locking, detachable distal fiber tip interface was designed

29 CFR 531.59 - The tip wage credit.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false The tip wage credit. 531.59 Section 531.59 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS WAGE PAYMENTS UNDER THE FAIR LABOR STANDARDS ACT OF 1938 Interpretations Payment of Wages to Tipped Employees...

Essential marketing tips: build your own brand one step at a time.

PubMed

Crowe, Candace

2010-11-01

This article discusses about physicians and their practice in terms of a "brand" that is described as one's persona and unique traits. By developing and portraying the uniqueness and singularity of the physician and the practice, one becomes open and transparent to clients for greatest patient satisfaction. Along with some background stories of well-known merchandise brands, presented are tips and advice for branding and selling oneself and one's medical practice. Very practical assignments are recommended for the physician to look at his or her own practice and how it appears to others on the "outside looking in." Copyright © 2010 Elsevier Inc. All rights reserved.

The Sea Level Rise Tipping Point of Delta Survival

NASA Astrophysics Data System (ADS)

Turner, R. E.; Kearney, M.; Parkinson, R. W.

2017-12-01

The estimated rate of global eustatic sea-level rise (RSLR) associated with the formation of thirty-six of the world's coastal deltas was calculated for the last 22,000 years. These deltas are located in a variety of environmental settings in respect to tidal range, isostasy, and climate. After correcting the original uncalibrated radiocarbon age estimates to calibrated years, 90% of the deltas appear to have formed at an average age of 8,109 ± 122 BP and a median age of 7,967 BP. This age corresponds to a period of significant deceleration in the RSLR to between 5 mm yr-1 and 10 mm yr-1, and is in agreement with two regional estimates of vegetation growth limits with respect to RSLR. This RSLR tipping point for delta formation can be used to inform forecasts of delta resiliency under conditions of climate change and concomitant sea level rise. The RSLR is accelerating and will likely be several times higher than the formation tipping point by the end of this century. Hence, the demise of the world's deltaic environments are likely to occur within the same time frame.

Oil-flow study of a Space Shuttle orbiter tip-fin controller

NASA Technical Reports Server (NTRS)

Helms, V. T., III

1983-01-01

Possible use of tip-fin controllers instead of a vertical tail on advanced winged entry vehicles was examined. Elimination of the vertical tail and using tip-fins offers the advantages of positive yaw control at high angles of attack and a potential weight savings. Oil-flow technique was used to obtain surface flow patterns on a tip-fin installed on a 0.01-scale Space Shuttle orbiter model for the purpose of assessing the extent of flow interference effects on the wing and tip-fin which might lead to serious heating problems. Tests were conducted in air at Mach 10 for a free-stream Reynolds numbers of .000113 at 20, 30, and 40 degree angle of attack and sideslip angles of 0 and 2 degree. Elevon deflections of -10, 0, and 10 degree and tip-fin control-surface deflections of 0, 20, and 40 degree were employed. Test results were also used to aid in the interpretation of heating data obtained on a Shuttle orbiter tip-fin on another model in a different facility. A limited comparison of oil-flow patterns and heat-transfer data is included. It was determined that elevon deflection angles from -10 to 10 degree and sideslip angles up to 2 degree have very little effect on tip-fin surface flow patterns. Also, there is a minimum of interference between the tip-fin and the wing. The most significant flow interactions occur on the tip-fin onboard surface as a result of its control-surface deflections.

Tips for Daily Living

MedlinePlus

... Stories of Returning to School or Work Tough Work If You Can Get It Home Modifications Mental Health Tips for Maintaining a Positive Outlook and Well-Being Recreation Can Increase Awareness Improving Memory Submitting Your Story Stroke families put the ‘connection’ ...

Neural network approximation of tip-abrasion effects in AFM imaging

NASA Astrophysics Data System (ADS)

Bakucz, Peter; Yacoot, Andrew; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf

2008-06-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods.

High Speed Imaging of Cavitation around Dental Ultrasonic Scaler Tips.

PubMed

Vyas, Nina; Pecheva, Emilia; Dehghani, Hamid; Sammons, Rachel L; Wang, Qianxi X; Leppinen, David M; Walmsley, A Damien

2016-01-01

Cavitation occurs around dental ultrasonic scalers, which are used clinically for removing dental biofilm and calculus. However it is not known if this contributes to the cleaning process. Characterisation of the cavitation around ultrasonic scalers will assist in assessing its contribution and in developing new clinical devices for removing biofilm with cavitation. The aim is to use high speed camera imaging to quantify cavitation patterns around an ultrasonic scaler. A Satelec ultrasonic scaler operating at 29 kHz with three different shaped tips has been studied at medium and high operating power using high speed imaging at 15,000, 90,000 and 250,000 frames per second. The tip displacement has been recorded using scanning laser vibrometry. Cavitation occurs at the free end of the tip and increases with power while the area and width of the cavitation cloud varies for different shaped tips. The cavitation starts at the antinodes, with little or no cavitation at the node. High speed image sequences combined with scanning laser vibrometry show individual microbubbles imploding and bubble clouds lifting and moving away from the ultrasonic scaler tip, with larger tip displacement causing more cavitation.

High Speed Imaging of Cavitation around Dental Ultrasonic Scaler Tips

PubMed Central

Vyas, Nina; Pecheva, Emilia; Dehghani, Hamid; Sammons, Rachel L.; Wang, Qianxi X.; Leppinen, David M.; Walmsley, A. Damien

2016-01-01

Cavitation occurs around dental ultrasonic scalers, which are used clinically for removing dental biofilm and calculus. However it is not known if this contributes to the cleaning process. Characterisation of the cavitation around ultrasonic scalers will assist in assessing its contribution and in developing new clinical devices for removing biofilm with cavitation. The aim is to use high speed camera imaging to quantify cavitation patterns around an ultrasonic scaler. A Satelec ultrasonic scaler operating at 29 kHz with three different shaped tips has been studied at medium and high operating power using high speed imaging at 15,000, 90,000 and 250,000 frames per second. The tip displacement has been recorded using scanning laser vibrometry. Cavitation occurs at the free end of the tip and increases with power while the area and width of the cavitation cloud varies for different shaped tips. The cavitation starts at the antinodes, with little or no cavitation at the node. High speed image sequences combined with scanning laser vibrometry show individual microbubbles imploding and bubble clouds lifting and moving away from the ultrasonic scaler tip, with larger tip displacement causing more cavitation. PMID:26934340

Materials for advanced turbine engines. Volume 1: Advanced blade tip seal system

NASA Technical Reports Server (NTRS)

Zelahy, J. W.; Fairbanks, N. P.

1982-01-01

Project 3, the subject of this technical report, was structured toward the successful engine demonstration of an improved-efficiency, long-life, tip-seal system for turbine blades. The advanced tip-seal system was designed to maintain close operating clearances between turbine blade tips and turbine shrouds and, at the same time, be resistant to environmental effects including high-temperature oxidation, hot corrosion, and thermal cycling. The turbine blade tip comprised an environmentally resistant, activated-diffussion-bonded, monocrystal superalloy combined with a thin layer of aluminium oxide abrasive particles entrapped in an electroplated NiCr matrix. The project established the tip design and joint location, characterized the single-crystal tip alloy and abrasive tip treatment, and established the manufacturing and quality-control plans required to fully process the blades. A total of 171 blades were fully manufactured, and 100 were endurance and performance engine-tested.

Are you Scared Yet?: Evaluating Fear Appeal Messages in Tweets about the Tips Campaign.

PubMed

Emery, Sherry L; Szczypka, Glen; Abril, Eulàlia Puig; Kim, Yoonsang; Vera, Lisa

2014-04-01

In March 2012, the CDC launched "Tips from Former Smokers," a $54 million national campaign featuring individuals experiencing long-term health consequences of smoking. The campaign approach was based on strong evidence that anti-tobacco ads portraying fear, graphic images, and personal testimonials are associated with attitudinal and behavior change. Yet it was also controversial; critics cited the danger that viewers might reject such intensely graphic messages. Tasked with informing this debate, our study analyzes the corpus of Tips campaign-related tweets obtained via the Twitter Firehose. We provide a novel and rigorous method for media campaign evaluation within the framework of the Extended Parallel Process Model. Among the relevant Tweets, 87% showed evidence of message acceptance, while 7% exhibited message rejection.

26 CFR 31.3401(a)(16)-1 - Tips.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) EMPLOYMENT TAXES AND COLLECTION OF INCOME TAX AT SOURCE EMPLOYMENT TAXES AND COLLECTION OF INCOME TAX AT SOURCE Collection of Income Tax at Source § 31.3401(a)(16)-1 Tips. Tips paid to an employee are excepted from wages and hence...

STEM TIPS: Supporting the Beginning Secondary STEM Teacher

ERIC Educational Resources Information Center

Jones, Griff; Dana, Thomas; LaFramenta, Joanne; Adams, Thomasenia Lott; Arnold, Jason Dean

2016-01-01

The STEM TIPS mobile-ready support platform gives institutions or school districts the ability to provide immediate and customized mentoring to teachers through multiple tiers of web-based support and resources. Using the results of a needs assessment, STEM TIPS was created and launched in partnership with 18 Florida school districts. Further…

Tip moth parasitoids and pesticides: Are they compatible?

Treesearch

Kenneth W. McCravy; Mark J. Dalusky; C. Wayne Berisford

1999-01-01

Effects of herbicide and insecticide applications on parasitism of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) were examined in 2-yr-old loblolly pine (Pinus taeda L.) plantations in Georgia. Total parasitism rates varied significantly among tip moth generations, but there were no differences in parasitism rates between herbicide-treated and untreated...

Acute Increase in Hepatic Arterial Flow During TIPS Identified by Intravascular Flow Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radeleff, Boris, E-mail: Boris_Radeleff@med.uni-heidelberg.de; Sommer, Christof-Matthias; Heye, Tobias

2009-01-15

The purpose of this study was to investigate alterations of hepatic arterial flow during transjugular intrahepatic portosystemic stent shunt (TIPS) applying intravascular Doppler sonography. This prospective monocenter study included 25 patients with liver cirrhosis (alcohol induced [n = 19], chronic hepatitis associated [n = 3], primary biliary cirrhosis associated [n = 1], and cryptogenic [n = 2]) successfully treated with TIPS. All patients underwent intravascular hepatic arterial flow measurements during TIPS using an endoluminal flow sensor. The average arterial peak velocity (APV) and the maximum arterial peak velocity (MPV) were registered. Twenty-two patients (88%) showed increased APV, one patient (4%)more » showed unaffected APV, and two patients (8%) showed decreased APV after TIPS. The average portosystemic pressure gradient decreased significantly, from 22.0 {+-} 5.1 mmHg before TIPS to 11.0 {+-} 4.1 mmHg after TIPS (-50.0%; p < 0.0001). The average APV increased significantly, from 41.9 {+-} 17.8 cm/s before TIPS to 60.7 {+-} 19.0 cm/s after TIPS (+44.9%; p < 0.0001). The average MPV increased significantly, from 90.8 {+-} 31.7 cm/s before TIPS to 112.6 {+-} 34.9 cm/s after TIPS (+24.0%; p = 0.0002). These changes in perfusion set in within seconds after TIPS tract formation in all the patients with increased APV. We conclude that TIPS-induced portosystemic decompression leads to a significant increase in hepatic arterial flow. The changes occurred within seconds, suggesting a reflex-like mechanism.« less

Cold-air performance of a 12.766-centimeter-tip-diameter axial-flow cooled turbine. 3: Effect of rotor tip clearance on overall performance of a solid blade configuration

NASA Technical Reports Server (NTRS)

Haas, J. E.; Kofskey, M. G.

1977-01-01

Two tip clearance configurations, one with a recess in the casing and the other with a reduced rotor blade height, were investigated at design equivalent speed over a range of tip clearance from about 2.0 to 5.0 percent of the stator blade height. The optimum configuration with a recess in the casing was the one where the rotor tip diameter was equal to the stator tip diameter (zero blade extension). For this configuration there was an approximate 1.5 percent decrease in total efficiency for an increase in tip clearance of 1 percent of stator blade height. For the reduced blade height configurations there was an approximate 2.0 percent decrease in total efficiency for an increase in tip clearance of 1 percent of stator blade height.

Disdrometer and Tipping Bucket Rain Gauge Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartholomew. MJ

2009-12-01

The Distromet disdrometer model RD-80 and NovaLynx tipping bucket rain gauge model 260-2500E-12 are two devices deployed a few meters apart to measure the character and amount of liquid precipitation. The main purpose of the disdrometer is to measure drop size distribution, which it does over 20 size classes from 0.3 mm to 5.4 mm. The data from both instruments can be used to determine rain rate. The disdrometer results can also be used to infer several properties including drop number density, radar reflectivity, liquid water content, and energy flux. Two coefficients, N0 and Λ, from an exponential fit betweenmore » drop diameter and drop number density, are routinely calculated. Data are collected once a minute. The instruments make completely different kinds of measurements. Rain that falls on the disdrometer sensor moves a plunger on a vertical axis. The disdrometer transforms the plunger motion into electrical impulses whose strength is proportional to drop diameter. The rain gauge is the conventional tipping bucket type. Each tip collects an amount equivalent to 0.01 in. of water, and each tip is counted by a data acquisition system anchored by a Campbell CR1000 data logger.« less

Identifying tips for intramolecular NC-AFM imaging via in situ fingerprinting

NASA Astrophysics Data System (ADS)

Sang, Hongqian; Jarvis, Samuel P.; Zhou, Zhichao; Sharp, Peter; Moriarty, Philip; Wang, Jianbo; Wang, Yu; Kantorovich, Lev

2014-10-01

A practical experimental strategy is proposed that could potentially enable greater control of the tip apex in non-contact atomic force microscopy experiments. It is based on a preparation of a structure of interest alongside a reference surface reconstruction on the same sample. Our proposed strategy is as follows. Spectroscopy measurements are first performed on the reference surface to identify the tip apex structure using a previously collected database of responses of different tips to this surface. Next, immediately following the tip identification protocol, the surface of interest is studied (imaging, manipulation and/or spectroscopy). The prototype system we choose is the mixed Si(111)-7×7 and surface which can be prepared on the same sample with a controlled ratio of reactive and passivated regions. Using an ``in silico'' approach based on ab initio density functional calculations and a set of tips with varying chemical reactivities, we show how one can perform tip fingerprinting using the Si(111)-7×7 reference surface. Then it is found by examining the imaging of a naphthalene tetracarboxylic diimide (NTCDI) molecule adsorbed on surface that negatively charged tips produce the best intramolecular contrast attributed to the enhancement of repulsive interactions.

Electrochemical etching technique of platinum-iridium tips for scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Herrera, Oscar

The scanning tunneling microscope (STM) allows researchers to investigate atomic and molecular structures and properties of nanomaterials. Through the quantum tunneling effect a charge is transferred between the surface of the material and a Platinum-Iridium (Pt-Ir) tip. The production of Pt-Ir tips by electrochemical etching (ECE) has been developed as an alternative technique, to achieve enhanced scanned images of samples, in contrast to the standard mechanical method (SMM). The sharpness apex structure is an essential feature during scanning in order to provide reliable data. We generated a control group of tips by the SMM technique and another group by the ECE technique to investigate the resolution effectiveness in scanning of graphite. The etching of the tips was produced using an auto-variable transformer running a 30 V AC in a 1.5 and 4.0 M CaCl2 solution. The scanning of the graphite surface was conducted at 7x7 nm image width, 0.2 seconds time/line, 256 points/line and 0.05 V for tip voltage. ECE etched tips displayed consistent image resolution, and the sharpness of the tip apex was generally uniform.

Sea trials of a ducted tip propeller designed for improved cavitation performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hordnes, I.; Bidaud, A.; Green, S.I.

1994-12-31

Studies have shown that ``ring-wing`` or ``ducted`` tip devices reduce substantially the inception index of trailing vortices generated by a hydrofoil (Green et al. 1988). It has also been shown that these devices improve the lift/drag ratio of an airfoil at high angle of incidence (Duan et al. 1992). These finding indicate that there may be a marine application for the ducted tip. Experimental equipment has been designed and manufactured in preparation for upcoming tests of a propeller with ducted tips. The tips are tubes aligned with the propeller blade tips that will replace a radial fraction of the originalmore » blade tips equal to the diameter of the tubes. The tube dimensions have been chosen according to the span/tip diameter and chord/tip length ratios used by Duan et al. (1992), and the tubes will be given a curvature equal to the propeller tip radius. Field trials will be given a curvature equal to the propeller tip radius. Field trials will be conducted on a 36 inch diameter propeller that is used to propel a 45 ft. fishing (seine) boat operating in the coastal waters outside Vancouver. The performance of the propeller will be measured in terms of the propeller efficiency as a function of advance ratio. A special force transducer has been designed that is capable of recording both torque and thrust on the propeller shaft even though these are expected to produce shaft strains of different orders of magnitude. As a supplementary means of monitoring the propeller performance, a hydrophone will be located near the propeller wake in order to measure the tip vortex cavitation noise.« less

Tip leakage vortex dynamics and inception

NASA Astrophysics Data System (ADS)

Oweis, Ghanem; Ceccio, Steven; Jessup, Stuart; Chesnakas, Christopher; Fry, David

2002-11-01

The McCormick rule for tip vortex cavitation scaling predicts that cavitation should take place in the vortex where the average core pressure deficit from the free stream is the largest along the vortex tube. The average core pressure deficit can be calculated from the vortex core size and circulation and these can be measured by LDV or hot wire, among other methods. The same rule applies to the tip vortex from a wall-bounded hydrofoil. Recent cavitation inception experiments on a ducted propeller in the NSWCCD 36 inch water tunnel combined with PIV and LDV measurements of the tip vortex flow are described. These tests reveal a disagreement between the actual inception location and that predicted by the McCormick rule. It is hypothesized that in this case the inception mechanism is related to local flow phenomena associated with local vortex unsteadiness, as opposed to the average vortex parameters (core size and circulation) used in the viscous scaling rule of McCormick. Discussion of the flow field measurements, bubble population, and the noise production from the inception events is given.

Unveiling Singlet Fission Mediating States in TIPS-pentacene and its Aza Derivatives.

PubMed

Herz, Julia; Buckup, Tiago; Paulus, Fabian; Engelhart, Jens U; Bunz, Uwe H F; Motzkus, Marcus

2015-06-25

Femtosecond pump-depletion-probe experiments were carried out in order to shed light on the ultrafast excited-state dynamics of triisopropylsilylethynyl (TIPS)-pentacene and two nitrogen-containing derivatives, namely, diaza-TIPS-pentacene and tetraaza-TIPS-pentacene. Measurements performed in the visible and near-infrared spectral range in combination with rate model simulations reveal that singlet fission proceeds via the extremely short-lived intermediate (1)TT state, which absorbs in the near-infrared spectral region only. The T1 → T3 transition probed in the visible region shows a rise time that comprises two components according to a consecutive reaction (S1 → (1)TT → T1). The incorporation of nitrogen atoms into the acene structure leads to shorter dynamics, but the overall triplet formation follows the same kinetic model. This is of particular importance, since experiments on tetraaza-TIPS-pentacene allow for investigation of the triplet state in the visible range without an overlapping singlet contribution. In addition, the pump-depletion-probe experiments show that the triplet absorption in the visible (T1 → T3) and near-infrared (T1 → T2) regions occurs from the same initial state, which was questioned in previous studies. Furthermore, an additional ultrafast transfer between the excited triplet states (T3 → T2) is identified, which is also in agreement with the rate model simulation. By applying depletion pulses, which are resonant with higher vibrational levels, we gain insight into internal vibrational energy redistribution processes within the triplet manifold. This additional information is of great relevance regarding the study of loss channels within these materials.

Influence of wing tip morphology on vortex dynamics of flapping flight

NASA Astrophysics Data System (ADS)

Krishna, Swathi; Mulleners, Karen

2013-11-01

The mechanism of flapping wing flight provides insects with extraordinary flight capabilities. The uniquely shaped wing tips give insects an edge in flight performance and the interaction between the leading edge vortices and wing tip vortices enhance their propelling efficiencies and manoeuvrability. These are qualities that are sought after in current-day Micro Air Vehicles. A detailed understanding of the vortex dynamics of flapping flight and the influence of the wing tip planform is imperative for technical application. An experimental study is conducted to investigate the effects of different wing tip planforms on the formation, evolution and interaction of vortical structures. We thereby focus on the interaction between the coherent structures evolving from the leading edge and the wing tip during pitching and flapping motions.The spatial and temporal evolution of the three-dimensional flow structures are determined using Scanning (Stereo) Particle Image Velocimetry and an in-depth coherent structure analysis. By comparing the vortex dynamics, the aerodynamic performance of various wing tip planforms are evaluated.

Numerical investigation of tip clearance cavitation in Kaplan runners

NASA Astrophysics Data System (ADS)

Nikiforova, K.; Semenov, G.; Kuznetsov, I.; Spiridonov, E.

2016-11-01

There is a gap between the Kaplan runner blade and the shroud that makes for a special kind of cavitation: cavitation in the tip leakage flow. Two types of cavitation caused by the presence of clearance gap are known: tip vortex cavitation that appears at the core of the rolled up vortex on the blade suction side and tip clearance cavitation that appears precisely in the gap between the blade tip edge and the shroud. In the context of this work numerical investigation of the model Kaplan runner has been performed taking into account variable tip clearance for several cavitation regimes. The focus is put on investigation of structure and origination of mechanism of cavitation in the tip leakage flow. Calculations have been performed with the help of 3-D unsteady numerical model for two-phase medium. Modeling of turbulent flow in this work has been carried out using full equations of Navier-Stokes averaged by Reynolds with correction for streamline curvature and system rotation. For description of this medium (liquid-vapor) simplification of Euler approach is used; it is based on the model of interpenetrating continuums, within the bounds of this two- phase medium considered as a quasi-homogeneous mixture with the common velocity field and continuous distribution of density for both phases. As a result, engineering techniques for calculation of cavitation conditioned by existence of tip clearance in model turbine runner have been developed. The detailed visualization of the flow was carried out and vortex structure on the suction side of the blade was reproduced. The range of frequency with maximum value of pulsation was assigned and maximum energy frequency was defined; it is based on spectral analysis of the obtained data. Comparison between numerical computation results and experimental data has been also performed. The location of cavitation zone has a good agreement with experiment for all analyzed regimes.

Characteristics of tip-leakage flow in an axial fan

NASA Astrophysics Data System (ADS)

Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol

2014-11-01

An axial fan with a shroud generates complicated vortical structures by the interaction of the axial flow with the fan blades and shroud near the blade tips. Large eddy simulation (LES) is performed for flow through a forward-swept axial fan, operating at the design condition of Re = 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model (Lee et al. 2010) is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame (Kim & Choi 2006) is adopted for the present simulation. It is found that two vortical structures are formed near the blade tip: the main tip leakage vortex (TLV) and the auxiliary TLV. The main TLV is initiated near the leading edge, develops downstream, and impinges on the pressure surface of the next blade, where the pressure fluctuations and turbulence intensity become high. On the other hand, the auxiliary TLV is initiated at the aft part of the blade but is relatively weak such that it merges with the main TLV. Supported by the KISTI Supercomputing Center (KSC-2014-C2-014).

Writing IS Teaching Tips: Guidelines for "JISE" Submission

ERIC Educational Resources Information Center

Lending, Diane; Vician, Chelley

2012-01-01

"JISE" has a lengthy history of inviting the submission of Teaching Tips for publication consideration in the journal. Past submission guidance for Teaching Tips has consisted of asking contributors to document the teaching experience and indicate what has worked, and not worked, in its execution within a journal page constraint of one to five…

Using High-Content Imaging to Analyze Toxicological Tipping ...

EPA Pesticide Factsheets

Presentation at International Conference on Toxicological Alternatives & Translational Toxicology (ICTATT) held in China and Discussing the possibility of using High Content Imaging to Analyze Toxicological Tipping Points Slide Presentation at International Conference on Toxicological Alternatives & Translational Toxicology (ICTATT) held in China and Discussing the possibility of using High Content Imaging to Analyze Toxicological Tipping Points

A new way to make diamond tip hosting an atomic sized defect

NASA Astrophysics Data System (ADS)

Zhou, Tony; Stohr, Rainer; Dovzhenko, Yuliya; Casola, Francesco; Yacoby, Amir

The nitrogen-vacancy (NV) center in diamond has been fascinating people with its unique role in quantum information and magnetometry. NV magnetometry was used to investigate many fundamental physics studies and develop a number of industrial applications. One of the powerful aspects of NV magnetometry is the ability to scan in space to perform spatial magnetic field sensing with nano-meter resolution. As a new emerging scanning probe technique, it faces a huge challenge to be widely adopted due to its complexity in fabrication. Here, we report a new simple way of creating diamond tips with tools found in basic clean room facilities and mount the tips onto an experimental apparatus with common lab bench tools. Finally, scanning NV magnetometry was performed to demonstrate its application. This work is supported by the QuASAR project and the Gordon and Betty Moore Foundations EPiQS Initiative through Grant GBMF4531.

Tip Vortex Cavitation

NASA Astrophysics Data System (ADS)

Maines, Brant H.; Arndt, Roger E. A.

2000-11-01

Cavitation in vortical flows is a problem of practical importance, that is relatively unexplored. Vortical structures of importance range from the eddies occurring randomly in space and time in turbulent flows to the developed vortices that occur at the tips of lifting surfaces and at the hubs of propellers and hydraulic turbines. A variety of secondary flow phenomena such as the horse shoe vortices that form around bridge piers, chute blocks and struts, and the secondary vortices found in the clearance passages of turbomachinery are also important cavitation sites. Tip vortex cavitation can be viewed as a canonical problem that captures many of the essential physics associated with vortex cavitation in general. This paper describes the inception process and focuses on the high levels of tension that can be sustained in the flow, which appears to scale with the blade loading. High speed video visualization indicates that the details of how free stream nuclei are ingested plays a major role in the nucleation and inception process. A new photographic technique was used to obtain high quality images of the bubble growth process at framing rates as high as 40,000 fps. Sponsored by the Office of Naval Research

Tips to Prevent Tick Bites

EPA Pesticide Factsheets

Using the right insect repellent and other preventive actions can discourage ticks, mosquitoes, and other biting insects from landing on you. Tips include avoiding tick habitats and minimizing exposed skin.

The Nantucket pine tip moth: old problems, new research. Proceedings of an informal conference, the Entomological Society of America, annual meeting. 1999 December 12-16

Treesearch

C. Wayne Berisford; Donald M. Grosman; [Editors

2002-01-01

The Nantucket pine tip moth, Rhyacionia frustrana (Comstock) has become a more prevalent pest in the South as pine plantation management has intensified. The Pine Tip Moth Research Consortium was formed in 1995 to increase basic knowledge about the moth and to explore ways to reduce damage. A conference was held in 1999 at the Entomological Society...

Measurement of Rotating Blade Tip Clearance with Fibre-Optic Probe

NASA Astrophysics Data System (ADS)

Cao, S. Z.; Duan, F. J.; Zhang, Y. G.

2006-10-01

This paper described a tip clearance measuring system with fibre-optic probe. The system is based on a novel tip clearance sensor of optical fibre-bundle mounted on the casing, rotating speed synchronization sensor mounted on the rotating shaft, the tip clearance preamplification processing circuit followed by high speed data-acquisition unit. A novel tip clearance sensor of trifurcated optical fibre bundle was proposed and demonstrated. It is independent of material of measured surface but capacitive probe demands target conductive. Measurements can be taken under severe conditions such as ionization. Sensor circuitry and data acquisition circuit were successfully designed. With the help of Rotation synchronized sensor, all the blades can be detected in real-time. Because of fibre-optic sensor, the measuring system has commendably frequency response, which can work well in high rotating speed from 0-15000rpm.The measurement range of tip clearance is 0-3mm with 25um precision.

Reproducible fabrication and applications of superconducting scanning tunneling microscope tips

NASA Astrophysics Data System (ADS)

Naaman, Ofer; Teizer, Winfried; Dynes, Robert C.

2001-03-01

We report on a method developed in our lab, for the fabrication of superconducting scanning tunneling microscope (STM) tips in a reproducible fashion. The fabrication process relies on sequential deposition of superconducting Pb and a proximity-coupled Ag capping layer onto a Pt/Ir tip. The tips were characterized by tunneling into both normal-metal and superconducting films, and the results confirm that the tips are superconducting with Tc and Δ close to that of bulk lead. The lead phonon structure in the tunneling density of states was observed, indicating a single step tunneling process. In an attempt to form STM Josephson junctions, we used our tips to form S/I/S junctions with R_NN ~50-100 kΩ. Results from spectroscopic measurements of these junctions at 2.0 K are discussed within the framework of the Ivanchenko and Zil'berman theory (Soviet Physics JETP, vol.28, 1272; 1969) of Josephson tunneling in the presence of strong phase fluctuations.

Low-coherence interferometric tip-clearance probe

NASA Astrophysics Data System (ADS)

Kempe, Andreas; Schlamp, Stefan; Rösgen, Thomas; Haffner, Ken

2003-08-01

We propose an all-fiber, self-calibrating, economical probe that is capable of near-real-time, single-port, simultaneous blade-to-blade tip-clearance measurements with submillimeter accuracy (typically <100 μm, absolute) in the first stages of a gas turbine. Our probe relies on the interference between backreflected light from the blade tips during the 1-μs blade passage time and a frequency-shifted reference with variable time delay, making use of a low-coherence light source. A single optical fiber of arbitrary length connects the self-contained optics and electronics to the turbine.

Selectable-Tip Corrosion-Testing Electrochemical Cell

NASA Technical Reports Server (NTRS)

Lomness, Janice; Hintze, Paul

2008-01-01

The figure depicts aspects of an electrochemical cell for pitting- corrosion tests of material specimens. The cell is designed to generate a region of corrosion having a pit diameter determined by the diameter of a selectable tip. The average depth of corrosion is controlled by controlling the total electric charge passing through the cell in a test. The cell is also designed to produce minimal artifacts associated with crevice corrosion. There are three selectable tips, having diameters of 0.1 in. (0.254 cm), 0.3 in. (0.762 cm), and 0.6 in. (1.524 cm), respectively.

Tip-Based Nanofabrication for Scalable Manufacturing

DOE PAGES

Hu, Huan; Kim, Hoe; Somnath, Suhas

2017-03-16

Tip-based nanofabrication (TBN) is a family of emerging nanofabrication techniques that use a nanometer scale tip to fabricate nanostructures. Here in this review, we first introduce the history of the TBN and the technology development. We then briefly review various TBN techniques that use different physical or chemical mechanisms to fabricate features and discuss some of the state-of-the-art techniques. Subsequently, we focus on those TBN methods that have demonstrated potential to scale up the manufacturing throughput. Finally, we discuss several research directions that are essential for making TBN a scalable nano-manufacturing technology.

Tip-Based Nanofabrication for Scalable Manufacturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Huan; Kim, Hoe; Somnath, Suhas

Tip-based nanofabrication (TBN) is a family of emerging nanofabrication techniques that use a nanometer scale tip to fabricate nanostructures. Here in this review, we first introduce the history of the TBN and the technology development. We then briefly review various TBN techniques that use different physical or chemical mechanisms to fabricate features and discuss some of the state-of-the-art techniques. Subsequently, we focus on those TBN methods that have demonstrated potential to scale up the manufacturing throughput. Finally, we discuss several research directions that are essential for making TBN a scalable nano-manufacturing technology.

Towards quantitative off-axis electron holographic mapping of the electric field around the tip of a sharp biased metallic needle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beleggia, M.; Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin; Kasama, T.

We apply off-axis electron holography and Lorentz microscopy in the transmission electron microscope to map the electric field generated by a sharp biased metallic tip. A combination of experimental data and modelling provides quantitative information about the potential and the field around the tip. Close to the tip apex, we measure a maximum field intensity of 82 MV/m, corresponding to a field k factor of 2.5, in excellent agreement with theory. In order to verify the validity of the measurements, we use the inferred charge density distribution in the tip region to generate simulated phase maps and Fresnel (out-of-focus) imagesmore » for comparison with experimental measurements. While the overall agreement is excellent, the simulations also highlight the presence of an unexpected astigmatic contribution to the intensity in a highly defocused Fresnel image, which is thought to result from the geometry of the applied field.« less

Direct mechanical stimulation of tip links in hair cells through DNA tethers

PubMed Central

Basu, Aakash; Lagier, Samuel; Vologodskaia, Maria; Fabella, Brian A; Hudspeth, AJ

2016-01-01

Mechanoelectrical transduction by hair cells commences with hair-bundle deflection, which is postulated to tense filamentous tip links connected to transduction channels. Because direct mechanical stimulation of tip links has not been experimentally possible, this hypothesis has not been tested. We have engineered DNA tethers that link superparamagnetic beads to tip links and exert mechanical forces on the links when exposed to a magnetic-field gradient. By pulling directly on tip links of the bullfrog's sacculus we have evoked transduction currents from hair cells, confirming the hypothesis that tension in the tip links opens transduction channels. This demonstration of direct mechanical access to tip links additionally lays a foundation for experiments probing the mechanics of individual channels. DOI: http://dx.doi.org/10.7554/eLife.16041.001 PMID:27331611

Study of tip clearance flow in a turbomachinery cascade using large eddy simulation

NASA Astrophysics Data System (ADS)

You, Donghyun

In liquid handling systems like pumps and ducted propulsors, low pressure events in the vicinity and downstream of the rotor tip gap can induce tip-leakage cavitation which leads to noise, vibration, performance loss, and erosions of blade and casing wall. In order to analyze the dynamics of the tip-clearance flow and determine the underlying mechanism for the low pressure events, a newly developed large-eddy simulation (LES) solver which combines an immersed-boundary method with a generalized curvilinear structured grid has been employed. An analysis of the LES results has been performed to understand the mean flow field, turbulence characteristics, vortex dynamics, and pressure fluctuations in the turbomachinery cascade with tip gap. In the cascade passage, the tip-leakage jet, which is generated by the pressure difference between the pressure and suction sides of the blade tip, is found to produce highly enhanced vorticity magnitude and significant levels of turbulent kinetic energy. Based on the understanding of the flow field, a guideline for reducing viscous loss in the cascade is provided. Analyses of the energy spectra and space-time correlations of the velocity fluctuations suggest that the tip-leakage vortex is subject to pitchwise wandering motion. The largest pressure drop and most intense pressure fluctuations due to the formation of the tip-leakage vortex are found at the location where the strongest portion of the tip-leakage vortex is found. Present study suggests that the tip-leakage vortex needs to be controlled in its origin to reduce cavitation in the present configuration. The effects of tip-gap size on the end-wall vortical structures and on the velocity and pressure fields have been investigated. The present analysis indicates that the mechanism for the generation of the vorticity and turbulent kinetic energy is mostly unchanged by the tip-gap size variation. However, larger tip-gap sizes are found to be more inductive to tip

Space charge limited current emission for a sharp tip

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Y. B., E-mail: zhuyingbin@gmail.com; Ang, L. K., E-mail: ricky-ang@sutd.edu.sg

In this paper, we formulate a self-consistent model to study the space charge limited current emission from a sharp tip in a dc gap. The tip is assumed to have a radius in the order of 10s nanometer. The electrons are emitted from the tip due to field emission process. It is found that the localized current density J at the apex of the tip can be much higher than the classical Child Langmuir law (flat surface). A scaling of J ∝ V{sub g}{sup 3/2}/D{sup m}, where V{sub g} is the gap bias, D is the gap size, and m = 1.1–1.2more » (depending on the emission area or radius) is proposed. The effects of non-uniform emission and the spatial dependence of work function are presented.« less

Employing Tip-Edge brackets on canines to simplify straight-wire mechanics.

PubMed

Rocke, R T

1994-10-01

The straight-wire appliance was developed in part to reduce wire bending and therefore make treatment results more predictable. Because tip prescription is built into the bracket slots, teeth are held at their final crown angulations throughout treatment. Straight-wire brackets are used in an attempt to produce bodily tooth movement. However, teeth tend to tip when a force is applied. This tipping, especially when canines are retracted, can deflect the arch wire causing supereruption of the incisors with a resultant increase in anterior overbite and an open bite in the canine/premolar area. Placing Tip-Edge brackets (TP Orthodontics, Inc., LaPorte, Ind.) on canines and employing tipping and uprighting mechanics on these teeth can overcome these problems. Two cases are presented to illustrate this approach to treatment.

Tips from the Classroom.

ERIC Educational Resources Information Center

Wilhelm, Kim Hughes; Leverett, Thomas; Barrett, Rob J.; Chur-Hansen, Anna; Dantas-Whitney, Maria; Zapata, Gabriela; Garcia, Juan Felix

1998-01-01

Five articles present tips for rallying English-as-a-Second-Language students to the enterprise of creating context, tools, and language itself. The articles focus on using original dramas created by students, teaching nonnative English-speaking medical students to comprehend their patients' colloquial language, conducting research with native…

Alternative Fuels Data Center: Goss' Garage Provides Tips for Using Ethanol

Science.gov Websites

in Classic Cars Goss' Garage Provides Tips for Using Ethanol in Classic Cars to someone by E -mail Share Alternative Fuels Data Center: Goss' Garage Provides Tips for Using Ethanol in Classic Cars on Facebook Tweet about Alternative Fuels Data Center: Goss' Garage Provides Tips for Using Ethanol

21 CFR 872.6650 - Massaging pick or tip for oral hygiene.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Massaging pick or tip for oral hygiene. 872.6650... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6650 Massaging pick or tip for oral hygiene. (a) Identification. A massaging pick or tip for oral hygiene is a rigid, pointed device intended...

Evaluation of a doubly-swept blade tip for rotorcraft noise reduction

NASA Technical Reports Server (NTRS)

Wake, Brian E.; Egolf, T. Alan

1992-01-01

A computational study was performed for a doubly-swept rotor blade tip to determine its benefit for high-speed impulsive (HSI) and blade-vortex interaction (BVI) noise. This design consists of aft and forward sweep. For the HSI-noise computations, unsteady Euler calculations were performed for several variations to a rotor blade geometry. A doubly-swept planform was predicted to increase the delocalizing Mach number to 0.94 (representative of a 200+ kt helicopter). For the BVI-noise problem, it had been hypothesized that the doubly-swept blade tip, by producing a leading-edge vortex, would reduce the tip-vortex effect on BVI noise. A procedure was used in which the tip vortex velocity profile computed by a Navier-Stokes solver was used to compute the inflow associated with BVI. This inflow was used by a Euler solver to compute the unsteady pressures for an acoustic analysis. The results of this study were inconclusive due to the difficulty in accurately predicting the viscous tip vortex downstream of the blade. Also, for the condition studied, no leading-edge vortex formed at the tip.

Nasal tip plasty: the delivery approach revisited.

PubMed

Xavier, Rui

2013-02-01

The delivery approach, though very appropriate for remodeling the tip of the nose, has been overlooked in recent years and has often been passed over for the open approach. One reason for this is the intercartilaginous incision used for the delivery approach, which may cause scarring at the nasal valve area, leading to postoperative functional obstruction of the nose. The delivery of the alar cartilages is another negative, as this maneuver will disrupt the collagen fibers that attach the upper lateral cartilages to the cephalic margin of the alar cartilages, leading to a weakening of the tip's support. We propose a modification to the traditional delivery approach by using a transcartilaginous instead of an intercartilaginous incision to prevent damage to the valve area. We also suggest taking advantage of the interference to the tip's support caused by the disruption of the collagen fibers of the scroll area. The purpose of this article is to describe this modification of the delivery approach and to emphasize the advantages that this controlled interference to the tip's support may have in selected cases. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Tips on Car Care & Safety for Deaf Drivers.

ERIC Educational Resources Information Center

National Highway Traffic Safety Administration (DOT), Washington, DC.

Primarily intended for the deaf or hard of hearing driver, this booklet contains many tips useful to all drivers. It is divided into two sections: Signs of Car Trouble and What to Do, and Safe Driving Tips and Special Situations. The rationale for section 1 is that a hearing driver can often tell that his car is not running properly or that some…

Large eddy simulation of tip-leakage flow in an axial flow fan

NASA Astrophysics Data System (ADS)

Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol; Kwon, Oh-Kyoung

2016-11-01

An axial flow fan with a shroud generates a complicated tip-leakage flow by the interaction of the axial flow with the fan blades and shroud near the blade tips. In this study, large eddy simulation is performed for tip-leakage flow in a forward-swept axial flow fan inside an outdoor unit of an air-conditioner, operating at the design condition of the Reynolds number of 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame is adopted. The present simulation clearly reveals the generation and evolution of tip-leakage vortex near the blade tip by the leakage flow. At the inception of the leakage vortex near the leading edge of the suction-side of the blade tip, the leakage vortex is composed of unsteady multiple vortices containing high-frequency fluctuations. As the leakage vortex develops downstream along a slant line toward the following blade, large and meandering movements of the leakage vortex are observed. Thus low-frequency broad peaks of velocity and pressure occur near the pressure surface. Supported by the KISTI Supercomputing Center (KSC-2016-C3-0027).

Quantum Molecular Dynamics Simulations of Nanotube Tip Assisted Reactions

NASA Technical Reports Server (NTRS)

Menon, Madhu

1998-01-01

In this report we detail the development and application of an efficient quantum molecular dynamics computational algorithm and its application to the nanotube-tip assisted reactions on silicon and diamond surfaces. The calculations shed interesting insights into the microscopic picture of tip surface interactions.

Analysis of capacitive force acting on a cantilever tip at solid/liquid interfaces

NASA Astrophysics Data System (ADS)

Umeda, Ken-ichi; Kobayashi, Kei; Oyabu, Noriaki; Hirata, Yoshiki; Matsushige, Kazumi; Yamada, Hirofumi

2013-04-01

Dielectric properties of biomolecules or biomembranes are directly related to their structures and biological activities. Capacitance force microscopy based on the cantilever deflection detection is a useful scanning probe technique that can map local dielectric constant. Here we report measurements and analysis of the capacitive force acting on a cantilever tip at solid/liquid interfaces induced by application of an alternating voltage to explore the feasibility of the measurements of local dielectric constant by the voltage modulation technique in aqueous solutions. The results presented here suggest that the local dielectric constant measurements by the conventional voltage modulation technique are basically possible even in polar liquid media. However, the cantilever deflection is not only induced by the electrostatic force, but also by the surface stress, which does not include the local dielectric information. Moreover, since the voltage applied between the tip and sample are divided by the electric double layer and the bulk polar liquid, the capacitive force acting on the apex of the tip are strongly attenuated. For these reasons, the lateral resolution in the local dielectric constant measurements is expected to be deteriorated in polar liquid media depending on the magnitude of dielectric response. Finally, we present the criteria for local dielectric constant measurements with a high lateral resolution in polar liquid media.

Allele compensation in tip60+/- mice rescues white adipose tissue function in vivo.

PubMed

Gao, Yuan; Hamers, Nicole; Rakhshandehroo, Maryam; Berger, Ruud; Lough, John; Kalkhoven, Eric

2014-01-01

Adipose tissue is a key regulator of energy homestasis. The amount of adipose tissue is largely determined by adipocyte differentiation (adipogenesis), a process that is regulated by the concerted actions of multiple transcription factors and cofactors. Based on in vitro studies in murine 3T3-L1 preadipocytes and human primary preadipocytes, the transcriptional cofactor and acetyltransferase Tip60 was recently identified as an essential adipogenic factor. We therefore investigated the role of Tip60 on adipocyte differentiation and function, and possible consequences on energy homeostasis, in vivo. Because homozygous inactivation results in early embryonic lethality, Tip60+/- mice were used. Heterozygous inactivation of Tip60 had no effect on body weight, despite slightly higher food intake by Tip60+/- mice. No major effects of heterozygous inactivation of Tip60 were observed on adipose tissue and liver, and Tip60+/- displayed normal glucose tolerance, both on a low fat and a high fat diet. While Tip60 mRNA was reduced to 50% in adipose tissue, the protein levels were unaltered, suggesting compensation by the intact allele. These findings indicate that the in vivo role of Tip60 in adipocyte differentiation and function cannot be properly addressed in Tip60+/- mice, but requires the generation of adipose tissue-specific knock out animals or specific knock-in mice.

Effect of ultrasonic tip designs on intraradicular post removal.

PubMed

Aguiar, Anny Carine Barros; de Meireles, Daniely Amorim; Marques, André Augusto Franco; Sponchiado Júnior, Emílio Carlos; Garrido, Angela Delfina Bitencourt; Garcia, Lucas da Fonseca Roberti

2014-11-01

To evaluate the effect of different ultrasonic tip designs on intraradicular post removal. The crowns of forty human canine teeth were removed, and after biomechanical preparation and filling, the roots were embedded in acrylic resin blocks. The post spaces were made, and root canal molding was performed with self-cured acrylic resin. After casting (Cu-Al), the posts were cemented with zinc phosphate cement. The specimens were randomly separated into 4 groups (n = 10), as follows: G1 - no ultrasonic vibration (control); G2 - ultrasonic vibration using an elongated cylindrical-shaped and active rounded tip; G3 - ultrasonic vibration with a flattened convex and linear active tip; G4 - ultrasonic vibration with active semicircular tapered tip. Ultrasonic vibration was applied for 15 seconds on each post surface and tensile test was performed in a Universal Testing Machine (Instron 4444 - 1 mm/min). G4 presented the highest mean values, however, with no statistically significant difference in comparison to G3 (P > 0.05). G2 presented the lowest mean values with statistically significant difference to G3 and G4 (P < 0.05). Ultrasonic vibration with elongated cylindrical-shaped and active rounded tip was most effective in reducing force required for intraradicular post removal.

Rhinoplasty. The difficult nasal tip: total resection of the alar cartilages.

PubMed

Rodriguez-Camps, Salvador

2009-01-01

There are many ways to reconstruct and make nasal tips more attractive. Sometimes we cannot find the best way unless we at least remove all surplus from the tip. This may occur in primary or secondary rhinoplasty. In principle, anything is possible when relocating and reconstructing. However, sometimes we face reality when we uncover the tip: broken or bulging cartilages that are difficult to put right. For this reason, in 1987 we thought of totally resectioning the alar cartilages in a case of secondary rhinoplasty with an unsightly appearance. After a year the result was seen to be correct from an aesthetic and a functional perspective and is still so today. Aesthetically, it kept its shape and did not collapse with nasal respiratory failure. We covered the end of the crus medialis with a small, temporary, one- to two-layered fascia patch. Except in exceptional cases, we now use this procedure: Total sectioning of the alar cartilages including the domes, or maintenance of them by preserving the fibroadipose tip tissue with a suture in the middle of the end of the crus medialis and by covering this with temporary fascia, which usually has two layers depending on the thickness of the skin of the tip. This procedure is indicated mainly in secondary rhinoplasty when the cartilages of the tip are completely destroyed, and in primary rhinoplasty when the tip is excessively wide and bulbous. Our philosophy is, therefore, elegance and beauty of the nasal tip with a solid and equilateral base without prejudices.

Simulation of Tip-Sample Interaction in the Atomic Force Microscope

NASA Technical Reports Server (NTRS)

Good, Brian S.; Banerjea, Amitava

1994-01-01

Recent simulations of the interaction between planar surfaces and model Atomic Force Microscope (AFM) tips have suggested that there are conditions under which the tip may become unstable and 'avalanche' toward the sample surface. Here we investigate via computer simulation the stability of a variety of model AFM tip configurations with respect to the avalanche transition for a number of fcc metals. We perform Monte-Carlo simulations at room temperature using the Equivalent Crystal Theory (ECT) of Smith and Banerjea. Results are compared with recent experimental results as well as with our earlier work on the avalanche of parallel planar surfaces. Our results on a model single-atom tip are in excellent agreement with recent experiments on tunneling through mechanically-controlled break junctions.

Cooling circuit for a gas turbine bucket and tip shroud

DOEpatents

Willett, Fred Thomas

2004-07-13

An open cooling circuit for a gas turbine airfoil and associated tip shroud includes a first group of cooling holes internal to the airfoil and extending in a radially outward direction generally along a leading edge of the airfoil; a second group of cooling holes internal to the airfoil and extending in a radially outward direction generally along a trailing edge of the airfoil. A common plenum is formed in the tip shroud in direct communication with the first and second group of cooling holes, but a second plenum may be provided for the second group of radial holes. A plurality of exhaust holes extends from the plenum(s), through the tip shroud and opening along a peripheral edge of the tip shroud.

Fitness: Tips for Staying Motivated

MedlinePlus

... life. Review these tips whenever you feel your motivation slipping. Identifying your fitness goals. American Heart Association. ... prescription. Primary Care. 2013;40:801. Physical activity: Motivation. Centers for Disease Control and Prevention. http://www. ...

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips.

PubMed

Tewari, Sumit; Bastiaans, Koen M; Allan, Milan P; van Ruitenbeek, Jan M

2017-01-01

Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

Effect of display update interval, update type, and background on perception of aircraft separation on a cockpit display on traffic information

NASA Technical Reports Server (NTRS)

Jago, S.; Baty, D.; Oconnor, S.; Palmer, E.

1981-01-01

The concept of a cockpit display of traffic information (CDTI) includes the integration of air traffic, navigation, and other pertinent information in a single electronic display in the cockpit. Concise display symbology was developed for use in later full-mission simulator evaluations of the CDTI concept. Experimental variables used included the update interval motion of the aircraft, the update type, (that is, whether the two aircraft were updated at the same update interval or not), the background (grid pattern or no background), and encounter type (straight or curved). Only the type of encounter affected performance.

Comparison of actual vacuum pressures at the end of 3 phacoemulsification tips in swine eyes.

PubMed

Park, Sang Hoon; Choi, Chul Young; Kim, Joon Mo; Chang, Hae Ran; Kim, Jae Yong; Kim, Myoung Joon; Tchah, Hungwon; Kim, Jae Chan

2009-05-01

To compare the actual vacuum pressure at the end of an aspiration bypass system (ABS) phaco tip and a conventional tip in conditions similar to those during human cataract surgery. Kangbuk Samsung Hospital, Seoul, Korea. A 4.0 mm diameter rubber eraser ball was inserted in a phacoemulsified swine eye and engaged to a phaco tip. With a vacuum pressure of 300 mm Hg, the eraser ball was pulled in the opposite direction with the phaco tip. The pulling power separating the eraser ball from the phaco tip was measured using the volume of water dripped into a container connected to the eraser ball. Measurements were taken with an Infiniti ABS tip and 2 conventional tips: Sovereign (conventional tip S) and Infiniti (conventional tip I). Measurements were taken alternatively at random in the same eye. The mean pulling power was 17.35 mL +/- 5.01 (SD) with conventional tip S and 16.85 +/- 4.45 mL with conventional tip I. The mean pulling power of the ABS tip was 13.35 +/- 4.32 mL, which was a mean 20.8% lower than that of conventional tip I (P = .016) and 23.1% lower than that of conventional tip S (P = .010). The actual vacuum pressure of the phaco tip was significantly influenced by the presence of the ABS hole. To compensate for the decrease in actual vacuum pressure, surgeons should be aware of the characteristics of the ABS tip being used and change the standard settings accordingly.

Compound parabolic concentrator optical fiber tip for FRET-based fluorescent sensors

NASA Astrophysics Data System (ADS)

Ul Hassan, Hafeez; Nielsen, Kristian; Aasmul, Soren; Bang, Ole

2015-09-01

The Compound Parabolic Concentrator (CPC) optical fiber tip shape has been proposed for intensity based fluorescent sensors working on the principle of FRET (Förster Resonance Energy Transfer). A simple numerical Zemax model has been used to optimize the CPC tip geometry for a step-index multimode polymer optical fiber for an excitation and emission wavelength of 550 nm and 650nm, respectively. The model suggests an increase of a factor of 1.6 to 4 in the collected fluorescent power for an ideal CPC tip, as compared to the plane-cut fiber tip for fiber lengths between 5 and 45mm.

Femtosecond laser micromachining of compound parabolic concentrator fiber tipped glucose sensors.

PubMed

Hassan, Hafeez Ul; Lacraz, Amédée; Kalli, Kyriacos; Bang, Ole

2017-03-01

We report on highly accurate femtosecond (fs) laser micromachining of a compound parabolic concentrator (CPC) fiber tip on a polymer optical fiber (POF). The accuracy is reflected in an unprecedented correspondence between the numerically predicted and experimentally found improvement in fluorescence pickup efficiency of a Förster resonance energy transfer-based POF glucose sensor. A Zemax model of the CPC-tipped sensor predicts an optimal improvement of a factor of 3.96 compared to the sensor with a plane-cut fiber tip. The fs laser micromachined CPC tip showed an increase of a factor of 3.5, which is only 11.6% from the predicted value. Earlier state-of-the-art fabrication of the CPC-shaped tip by fiber tapering was of so poor quality that the actual improvement was 43% lower than the predicted improvement of the ideal CPC shape.

Femtosecond laser micromachining of compound parabolic concentrator fiber tipped glucose sensors

NASA Astrophysics Data System (ADS)

Hassan, Hafeez Ul; Lacraz, Amédée; Kalli, Kyriacos; Bang, Ole

2017-03-01

We report on highly accurate femtosecond (fs) laser micromachining of a compound parabolic concentrator (CPC) fiber tip on a polymer optical fiber (POF). The accuracy is reflected in an unprecedented correspondence between the numerically predicted and experimentally found improvement in fluorescence pickup efficiency of a Förster resonance energy transfer-based POF glucose sensor. A Zemax model of the CPC-tipped sensor predicts an optimal improvement of a factor of 3.96 compared to the sensor with a plane-cut fiber tip. The fs laser micromachined CPC tip showed an increase of a factor of 3.5, which is only 11.6% from the predicted value. Earlier state-of-the-art fabrication of the CPC-shaped tip by fiber tapering was of so poor quality that the actual improvement was 43% lower than the predicted improvement of the ideal CPC shape.

Free-Space Oscillating Pressures Near the Tips of Rotating Propellers

NASA Technical Reports Server (NTRS)

Hubbard, Harvey H; Regier, Arthur A

1950-01-01

The theory is given for calculating the free-space oscillating pressures associated with a rotating propeller, at any point in space. Because of its complexity this analysis is convenient only for use in the critical region near the propeller tips where the assumptions used by Gutin to simplify his final equations are not valid. Good agreement was found between analytical and experimental results in the tip Mach number range 0.45 to two, three, four, five, six, on eight-blade propellers and for a range of tip clearances from 0.04 to 0.30 times the propeller diameter. If the power coefficient, tip Mach number, and the tip clearance are known for a given propeller, the designer may determine from these charts the average maximum free-space oscillating pressure in the critical region near the plane of rotation. A section of the report is devoted to the fuselage response to these oscillating pressures and indicates some of the factors to be considered in solving the problems of fuselage vibration and noise.

Phosphorylation regulates the water channel activity of the seed-specific aquaporin alpha-TIP.

PubMed

Maurel, C; Kado, R T; Guern, J; Chrispeels, M J

1995-07-03

The vacuolar membrane protein alpha-TIP is a seed-specific protein of the Major Intrinsic Protein family. Expression of alpha-TIP in Xenopus oocytes conferred a 4- to 8-fold increase in the osmotic water permeability (Pf) of the oocyte plasma membrane, showing that alpha-TIP forms water channels and is thus a new aquaporin. alpha-TIP has three putative phosphorylation sites on the cytoplasmic side of the membrane (Ser7, Ser23 and Ser99), one of which (Ser7) has been shown to be phosphorylated. We present several lines of evidence that the activity of this aquaporin is regulated by phosphorylation. First, mutation of the putative phosphorylation sites in alpha-TIP (Ser7Ala, Ser23Ala and Ser99Ala) reduced the apparent water transport activity of alpha-TIP in oocytes, suggesting that phosphorylation of alpha-TIP occurs in the oocytes and participates in the control of water channel activity. Second, exposure of oocytes to the cAMP agonists 8-bromoadenosine 3',5'-cyclic monophosphate, forskolin and 3-isobutyl-1-methylxanthine, which stimulate endogenous protein kinase A (PKA), increased the water transport activity of alpha-TIP by 80-100% after 60 min. That the protein can be phosphorylated by PKA was demonstrated by phosphorylating alpha-TIP in isolated oocyte membranes with the bovine PKA catalytic subunit. Third, the integrity of the three sites at positions 7, 23 and 99 was necessary for the cAMP-dependent increase in the Pf of oocytes expressing alpha-TIP, as well as for in vitro phosphorylation of alpha-TIP. These findings demonstrate that the alpha-TIP water channel can be modulated via phosphorylation of Ser7, Ser23 and Ser99.(ABSTRACT TRUNCATED AT 250 WORDS)

Tip vortices in the actuator line model

NASA Astrophysics Data System (ADS)

Martinez, Luis; Meneveau, Charles

2017-11-01

The actuator line model (ALM) is a widely used tool to represent the wind turbine blades in computational fluid dynamics without the need to resolve the full geometry of the blades. The ALM can be optimized to represent the `correct' aerodynamics of the blades by choosing an appropriate smearing length scale ɛ. This appropriate length scale creates a tip vortex which induces a downwash near the tip of the blade. A theoretical frame-work is used to establish a solution to the induced velocity created by a tip vortex as a function of the smearing length scale ɛ. A correction is presented which allows the use of a non-optimal smearing length scale but still provides the downwash which would be induced using the optimal length scale. Thanks to the National Science Foundation (NSF) who provided financial support for this research via Grants IGERT 0801471, IIA-1243482 (the WINDINSPIRE project) and ECCS-1230788.

Aeroelastic behavior of composite rotor blades with swept tips

NASA Technical Reports Server (NTRS)

Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

1992-01-01

This paper presents an analytical study of the aeroelastic behavior of composite rotor blades with straight and swept tips. The blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. The nonlinear equations of motion for the finite element model are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. It is shown that composite ply orientation has a substantial effect on blade stability. At low thrust conditions, certain ply orientations can cause instability in the lag mode. The flap-torsion coupling associated with tip sweep can also induce aeroelastic instability in the blade. This instability can be removed by appropriate ply orientation in the composite construction.

Twelve tips for medical students to establish a collaborative flashcard project.

PubMed

Hart-Matyas, Michael; Taylor, Alexandra; Lee, Han Joo; Maclean, Mark A; Hui, Amaris; Macleod, Anna

2018-01-29

Medical students employ various study strategies to master large amounts of information during their medical education. Digital flashcards are an interactive, self-directed study stool that may improve knowledge retention by combining the principles of active recall and spaced-repetition. They may be studied during and beyond undergraduate medical education. However, making flashcards can be an onerous task. In this article, we describe twelve tips on how to establish and maintain a collaborative digital flashcard project based on the undergraduate medical curriculum.

Influence of tip end-plate on noise of small axial fan

NASA Astrophysics Data System (ADS)

Mao, Hongya; Wang, Yanping; Lin, Peifeng; Jin, Yingzi; Setoguchi, Toshiaki; Kim, Heuy Dong

2017-02-01

In this work, tip end-plate is used to improve the noise performance of small axial fans. Both numerical simulations and experimental methods were adopted to study the fluid flow and noise level of axial fans. Four modified models and the prototype are simulated. Influences of tip end-plate on static characteristics, internal flow field and noise of small axial fans are analyzed. The results show that on basis of the prototype, the model with the tip end-plate of 2 mm width and changed length achieved best noise performance. The overall sound pressure level of the model with the tip end-plate of 2 mm width and changed length is 2.4 dB less than that of the prototype at the monitoring point in specified far field. It is found that the mechanism of noise reduction is due to the decrease of vorticity variation on the surface of blades caused by the tip end-plate. Compared with the prototype, the static pressure of the model with the tip end-plate of 2 mm width and changed length at design flow rate decreases by 2 Pa and the efficiency decreases by 0.8%. It is concluded that the method of adding tip end-plate to impeller blades has a positive influence on reducing noise, but it may diminish the static characteristics of small axial fan to some extent.

Computational Investigation of Novel Tip Leakage Mitigation Methods for High Pressure Turbine Blades

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir; Gupta, Abhinav; Shyam, Vikram

2014-01-01

This paper presents preliminary findings on a possible approach to reducing tip leakage losses. In this paper a computational study was conducted on the Energy Efficient Engine (EEE) High Pressure Turbine (HPT) rotor tip geometry using the commercial numerical solver ANSYS FLUENT. The flow solver was validated against aerodynamic data acquired in the NASA Transonic Turbine Blade Cascade facility. The scope of the ongoing study is to computationally investigate how the tip leakage and overall blade losses are affected by (1) injection from the tip near the pressure side, (2) injection from the tip surface at the camber line, and (3) injection from the tip surface into the tip separation bubble. The objective is to identify the locations on the tip surface at which to place appropriately configured blowing keeping in mind the film cooling application of tip blowing holes. The validation was conducted at Reynolds numbers of 85,000, 343,000, and 685,000 and at engine realistic flow conditions. The coolant injection simulations were conducted at a Reynolds number of 343,000 based on blade chord and inlet velocity and utilized the SST turbulence model in FLUENT. The key parameters examined are the number of jets, jet angle and jet location. A coolant to inlet pressure ratio of 1.0 was studied for angles of +30 deg, -30 deg, and 90 deg to the local free stream on the tip. For the 3 hole configuration, 3 holes spaced 3 hole diameters apart with length to diameter ratio of 1.5 were used. A simulation including 11 holes along the entire mean camber line is also presented (30 deg toward suction side). In addition, the effect of a single hole is also compared to a flat tip with no injection. The results provide insight into tip flow control methods and can be used to guide further investigation into tip flow control. As noted in past research it is concluded that reducing leakage flow is not necessarily synonymous with reducing losses due to leakage.

Computational Investigation of Novel Tip Leakage Mitigation Methods for High Pressure Turbine Blades

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir; Gupta, Abhinav; Shyam, Vikram

2014-01-01

This paper presents preliminary findings on a possible approach to reducing tip leakage losses. In this paper a computational study was conducted on the EEE (Energy Efficient Engine) HPT (High Pressure Turbine) rotor tip geometry using the commercial numerical solver ANSYS FLUENT. The flow solver was validated against aerodynamic data acquired in the NASA Transonic Turbine Blade Cascade facility. The scope of the ongoing study is to computationally investigate how the tip leakage and overall blade losses are affected by 1. injection from the tip near the pressure side, 2. injection from the tip surface at the camber line, and 3. injection from the tip surface into the tip separation bubble. The objective is to identify the locations on the tip surface at which to place appropriately configured blowing keeping in mind the film cooling application of tip blowing holes. The validation was conducted at Reynolds numbers of 85,000, 343,000 and 685,000 and at engine realistic flow conditions. The coolant injection simulations were conducted at a Reynolds number of 343,000 based on blade chord and inlet velocity and utilized the SST turbulence model in FLUENT. The key parameters examined are the number of jets, jet angle and jet location. A coolant to inlet pressure ratio of 1.0 was studied for angles of +30 deg., -30 deg. and 90 deg. to the local free stream on the tip. For the 3 hole configuration, 3 holes spaced 3 hole diameters apart with length to diameter ratio of 1.5 were used. A simulation including 11 holes along the entire mean camber line is also presented (30 degrees toward suction side). In addition, the effect of a single hole is also compared to a flat tip with no injection. The results provide insight into tip flow control methods and can be used to guide further investigation into tip flow control. As noted in past research it is concluded that reducing leakage flow is not necessarily synonymous with reducing losses due to leakage.

Effect of Tip-Speed Constraints on the Optimized Design of a Wind Turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dykes, K.; Resor, B.; Platt, A.

This study investigates the effect of tip-velocity constraints on system levelized cost of energy (LCOE). The results indicate that a change in maximum tip speed from 80 to 100~m/s could produce a 32% decrease in gearbox weight (a 33% reduction in cost) which would result in an overall reduction of 1%-9% in system LCOE depending on the design approach. Three 100~m/s design cases were considered including a low tip-speed ratio/high-solidity rotor design, a high tip-speed ratio/ low-solidity rotor design, and finally a flexible blade design in which a high tip-speed ratio was used along with removing the tip deflection constraintmore » on the rotor design. In all three cases, the significant reduction in gearbox weight caused by the higher tip-speed and lower overall gear ratio was counterbalanced by increased weights for the rotor and/or other drivetrain components and the tower. As a result, the increased costs of either the rotor or drivetrain components offset the overall reduction in turbine costs from down-sizing the gearbox. Other system costs were not significantly affected, whereas energy production was slightly reduced in the 100~m/s case low tip-speed ratio case and increased in the high tip-speed ratio case. This resulted in system cost of energy reductions moving from the 80~m/s design to the 100~m/s designs of 1.2% for the low tip-speed ratio, 4.6% for the high tip-speed ratio, and 9.5% for the final flexible case (the latter result is optimistic because the impact of deflection of the flexible blade on power production was not modeled). Overall, the results demonstrate that there is a trade-off in system design between the maximum tip velocity and the overall wind plant cost of energy, and there are many trade-offs within the overall system in designing a turbine for a high maximum tip velocity.« less

Tip Characterization Method using Multi-feature Characterizer for CD-AFM

PubMed Central

Orji, Ndubuisi G.; Itoh, Hiroshi; Wang, Chumei; Dixson, Ronald G.; Walecki, Peter S.; Schmidt, Sebastian W.; Irmer, Bernd

2016-01-01

In atomic force microscopy (AFM) metrology, the tip is a key source of uncertainty. Images taken with an AFM show a change in feature width and shape that depends on tip geometry. This geometric dilation is more pronounced when measuring features with high aspect ratios, and makes it difficult to obtain absolute dimensions. In order to accurately measure nanoscale features using an AFM, the tip dimensions should be known with a high degree of precision. We evaluate a new AFM tip characterizer, and apply it to critical dimension AFM (CD-AFM) tips used for high aspect ratio features. The characterizer is made up of comb-shaped lines and spaces, and includes a series of gratings that could be used as an integrated nanoscale length reference. We also demonstrate a simulation method that could be used to specify what range of tip sizes and shapes the characterizer can measure. Our experiments show that for non re-entrant features, the results obtained with this characterizer are consistent to 1 nm with the results obtained by using widely accepted but slower methods that are common practice in CD-AFM metrology. A validation of the integrated length standard using displacement interferometry indicates a uniformity of better than 0.75%, suggesting that the sample could be used as highly accurate and SI traceable lateral scale for the whole evaluation process. PMID:26720439

[Detection of single-walled carbon nanotube bundles by tip-enhanced Raman spectroscopy].

PubMed

Wu, Xiao-Bin; Wang, Jia; Wang, Rui; Xu, Ji-Ying; Tian, Qian; Yu, Jian-Yuan

2009-10-01

Raman spectroscopy is a powerful technique in the characterization of carbon nanotubes (CNTs). However, this spectral method is subject to two obstacles. One is spatial resolution, namely the diffraction limits of light, and the other is its inherent small Raman cross section and weak signal. To resolve these problems, a new approach has been developed, denoted tip-enhanced Raman spectroscopy (TERS). TERS has been demonstrated to be a powerful spectroscopic and microscopic technique to characterize nanomaterial or nanostructures. Excited by a focused laser beam, an enhanced electric field is generated in the vicinity of a metallic tip because of the surface plasmon polariton (SPP) and lightening rod effect. Consequently, Raman signal from the sample area illuminated by the enhanced field nearby the tip is enhanced. At the same time, the topography is obtained in the nanometer scale. The exact corresponding relationship between the localized Raman and the topography makes the Raman identification at the nanometer scale to be feasible. In the present paper, based on an inverted microscope and a metallic AFM tip, a tip-enhanced Raman system was set up. The radius of the Au-coated metallic tip is about 30 nm. The 532 nm laser passes through a high numerical objective (NA0.95) from the bottom to illuminate the tip to excite the enhanced electric field. Corresponding with the AFM image, the tip-enhanced near-field Raman of a 100 nm diameter single-walled carbon nanotube (SWNT) bundles was obtained. The SWNTs were prepared by arc method. Furthermore, the near-field Raman of about 3 SWNTs of the bundles was received with the spatial resolution beyond the diffraction limit. Compared with the far-field Raman, the enhancement factor of the tip-enhanced Raman is more than 230. With the super-diffraction spatial resolution and the tip-enhanced Raman ability, tip-enhanced Raman spectroscopy will play an important role in the nano-material and nano-structure characterization.

Defining toxicological tipping points in neuronal network development.

PubMed

Frank, Christopher L; Brown, Jasmine P; Wallace, Kathleen; Wambaugh, John F; Shah, Imran; Shafer, Timothy J

2018-02-02

Measuring electrical activity of neural networks by microelectrode array (MEA) has recently shown promise for screening level assessments of chemical toxicity on network development and function. Important aspects of interneuronal communication can be quantified from a single MEA recording, including individual firing rates, coordinated bursting, and measures of network synchrony, providing rich datasets to evaluate chemical effects. Further, multiple recordings can be made from the same network, including during the formation of these networks in vitro. The ability to perform multiple recording sessions over the in vitro development of network activity may provide further insight into developmental effects of neurotoxicants. In the current study, a recently described MEA-based screen of 86 compounds in primary rat cortical cultures over 12 days in vitro was revisited to establish a framework that integrates all available primary measures of electrical activity from MEA recordings into a composite metric for deviation from normal activity (total scalar perturbation). Examining scalar perturbations over time and increasing concentration of compound allowed for definition of critical concentrations or "tipping points" at which the neural networks switched from recovery to non-recovery trajectories for 42 compounds. These tipping point concentrations occurred at predominantly lower concentrations than those causing overt cell viability loss or disrupting individual network parameters, suggesting tipping points may be a more sensitive measure of network functional loss. Comparing tipping points for six compounds with plasma concentrations known to cause developmental neurotoxicity in vivo demonstrated strong concordance and suggests there is potential for using tipping points for chemical prioritization. Published by Elsevier Inc.

Top 10 "Secret Writing Tips" to Boost Your Productivity: Part 2

ERIC Educational Resources Information Center

Berk, Ronald A.

2011-01-01

This is the sequel and companion piece to the first five tips published in this journal's winter 2010 issue. To recap, the first five tips are: (1) Write Everyday; (2) Write Everywhere; (3) Conquer Distractions and Interruptions; (4) Write for a Niche; and (5) Write with a Purpose. Now, in this article, the other five tips are discussed: (6) Write…

Lightning Safety Tips and Resources

MedlinePlus

... Safety Brochure U.S. Lightning Deaths in 2018 : 5 Youtube: Lightning Safety for the Deaf and Hard of ... for Hard of Hearing: jpg , high res png YouTube: Lightning Safety Tips Lightning Safety When Working Outdoors : ...

Gas turbine blade film cooling and blade tip heat transfer

NASA Astrophysics Data System (ADS)

Teng, Shuye

The detailed heat transfer coefficient and film cooling effectiveness distributions as well as the detailed coolant jet temperature profiles on the suction side of a gas turbine blade were measured using a transient liquid crystal image method and a traversing cold wire and thermocouple probe, respectively. The blade has only one row of film holes near the gill hole portion on the suction side of the blade. The hole geometries studied include standard cylindrical holes and holes with diffuser shaped exit portion (i.e. fanshaped holes and laidback fanshaped holes). Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity was 5.3 x 105. The upstream unsteady wakes were simulated using a spoke-wheel type wake generator. The wake Strouhal number was kept at 0 and 0.1. The coolant blowing ratio was varied from 0.4 to 1.2. Results show that both expanded holes have significantly improved thermal protection over the surface downstream of the ejection location, particularly at high blowing ratios. However, the expanded hole injections induce earlier boundary layer transition to turbulence and enhance heat transfer coefficients at the latter part of the blade suction surface. In general, the unsteady wake tends to reduce film cooling effectiveness. Measurements of detailed heat transfer coefficient distributions on a turbine blade tip were performed in the same wind tunnel facility as above. The central blade had a variable tip gap clearance. Measurements were made at three different tip gap clearances of about 1.1%, 2.1%, and 3% of the blade span. Static pressure distributions were measured in the blade mid-span and on the shroud surface. Detailed heat transfer coefficient distributions were measured on the blade tip surface. Results show that reduced tip clearance leads to reduced heat transfer coefficient over the blade tip surface. Results also show that reduced tip clearance tends to

Investigation of rotor blade tip-vortex aerodynamics

NASA Technical Reports Server (NTRS)

Lewellen, W. S.

1971-01-01

Several aspects of the aerodynamics of rotor blade tip vortices are examined. Two particular categories are dealt with; (1) dynamic loads on a blade passing close to or intersecting a trailing vortex, and (2) the response of the trailing vortex core to changes in the flow. Results for both categories are in reasonable agreement with existing data, although lower pressure gradients were obtained than anticipated for category one. A correlation between trailing edge sweep angle at the tip and vortex core size was noted for category two.

Technology for fabrication of a micromagnet on a tip of a MFM/MRFM probe

DOEpatents

Pelekhov, Denis V.; Hammel, P. Chris; Nunes, Jr., Geoffrey; Midzor, Melissa M.; Roukes, Michael

2004-01-13

A method for coating the tip of a mechanical resonator for use in magnetic force microscopy and magnetic resonance force microscopy in which the tip is coated with a ferromagnetic material and the cantilever is not, and the product resulting from the method. A cantilever and incorporated tip are coated with a photoresist, except that surface tension keeps photoresist off the tip. The cantilever and tip are then coated with a magnetic material. Next, acetone is used to lift off the magnetic material from the cantilever but not from the tip.

Functionalization of Probe Tips and Supports for Single-Molecule Recognition Force Microscopy

NASA Astrophysics Data System (ADS)

Ebner, Andreas; Wildling, Linda; Zhu, Rong; Rankl, Christian; Haselgrübler, Thomas; Hinterdorfer, Peter; Gruber, Hermann J.

The measuring tip of a force microscope can be converted into a monomolecular sensor if one or few "ligand" molecules are attached to the apex of the tip while maintaining ligand function. Functionalized tips are used to study fine details of receptor-ligand interaction by force spectroscopy or to map cognate "receptor" molecules on the sample surface. The receptor (or target) molecules can be present on the surface of a biological specimen; alternatively, soluble target molecules must be immobilized on ultraflat supports. This review describes the methods of tip functionalization, as well as target molecule immobilization. Silicon nitride tips, silicon chips, and mica have usually been functionalized in three steps: (1) aminofunctionalization, (2) crosslinker attachment, and (3) ligand/receptor coupling, whereby numerous crosslinkers are available to couple widely different ligand molecules. Gold-covered tips and/or supports have usually been coated with a self-assembled monolayer, on top of which the ligand/receptor molecule has been coupled either directly or via a crosslinker molecule. Apart from these general strategies, many simplified methods have been used for tip and/or support functionalization, even single-step methods such as adsorption or chemisorption being very efficient under suitable circumstances. All methods are described with the same explicitness and critical parameters are discussed. In conclusion, this review should help to find suitable methods for specific problems of tip and support functionalization.

Tip-enhanced Raman spectroscopy and near-field polarization

NASA Astrophysics Data System (ADS)

Saito, Yuika; Mino, Toshihiro; Verma, Prabhat

2015-12-01

Tip-enhanced Raman spectroscopy (TERS) is a powerful tool for High-resolution Raman spectroscopy. In this method, a metal coated nano-tip acts as a plasmonic antenna to enhance the originally weak Raman scattering from a nanometric volume of a sample. The technique enables to detect Raman scattering light from nano-scale area and also enhance the light intensity with combination of near-filed light and localized surface plasmon generated at a metallized tip apex. Nowadays TERS is used to investigate various nano-scale samples, for examples, carbon nanotubes, graphenes DNA and biomaterials. As the TERS developed, there is high demand to investigate the properties of near-field light e.g. polarization properties. We have analyzed the polarization properties of near-field light in TERS and successfully realized the quantitative nano-imaging by visible light.

Progress Toward a Bulk Micromachined Tunneling Tip Microaccelerometer

NASA Technical Reports Server (NTRS)

Frank T. Hartley, Ben Dolgen, Paul M. Zavracky

1995-01-01

Ultrasensitive accelerometers are needed for microgravity measurement of orbital drag and active isolation systems. We have designed an accelerometer capable of measuring accelerations of the order of 10(i) g. A tunneling tip sensor can be used as a position sensor with a potential performance advantage of two orders of magnitude over capacitive sensors. In this paper, we disclose our progress in the fabrication and measurement of a bulk microaccelerometer which employs a tunneling tip. Fully assembled accelerometers consisting of four separate die have been fabricated. The device employs a unique folded spring system with a low spring constant. To protect the tunneling tip, we have employed electrostatic clamping. Stiction has not been observed, but the required clamping voltage is greater than expected. We have developed a simple model to analyze our results.

Taiwan: Background Notes Series.

ERIC Educational Resources Information Center

Reams, Joanne Reppert

Concise background information on Taiwan is provided. The publication begins with a profile of Taiwan, discussing the people, geography, political establishment, and economy. A map of the country is provided. The bulk of the publication then provides more detailed information on Taiwan's people, geography, history, administration, political…

Numerical Simulation of Tip Vortices of Wings in Subsonic and Transonic Flows,

DTIC Science & Technology

1986-01-01

roll-up of the tip vor- rv : dimensionless strength of tip vortex " tex in both subsonic and transonic flows. Four test cases which used small and large...of their po- tion and the roll-up of the tip vortex has been observed for tential hazard to aircraft that encounter them in flight. To all the cases...such flows encompassing large air- tip- vortex strength. craft wakes (see for example Refs. 1-2). In spite of this, the present understanding of such

CO tip functionalization in subatomic resolution atomic force microscopy

NASA Astrophysics Data System (ADS)

Kim, Minjung; Chelikowsky, James R.

2015-10-01

Noncontact atomic force microscopy (nc-AFM) employing a CO-functionalized tip displays dramatically enhanced resolution wherein covalent bonds of polycyclic aromatic hydrocarbon can be imaged. Employing real-space pseudopotential first-principles calculations, we examine the role of CO in functionalizing the nc-AFM tip. Our calculations allow us to simulate full AFM images and ascertain the enhancement mechanism of the CO molecule. We consider two approaches: one with an explicit inclusion of the CO molecule and one without. By comparing our simulations to existing experimental images, we ascribe the enhanced resolution of the CO functionalized tip to the special orbital characteristics of the CO molecule.

CO tip functionalization in subatomic resolution atomic force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Minjung; Chelikowsky, James R.

2015-10-19

Noncontact atomic force microscopy (nc-AFM) employing a CO-functionalized tip displays dramatically enhanced resolution wherein covalent bonds of polycyclic aromatic hydrocarbon can be imaged. Employing real-space pseudopotential first-principles calculations, we examine the role of CO in functionalizing the nc-AFM tip. Our calculations allow us to simulate full AFM images and ascertain the enhancement mechanism of the CO molecule. We consider two approaches: one with an explicit inclusion of the CO molecule and one without. By comparing our simulations to existing experimental images, we ascribe the enhanced resolution of the CO functionalized tip to the special orbital characteristics of the CO molecule.

Extraforaminal needle tip position reduces risk of intravascular injection in CT-fluoroscopic lumbar transforaminal epidural steroid injections

PubMed Central

Yu, Robinson K.; Ghodadra, Anish; Agarwal, Vikas

2016-01-01

Background Lumbar transforaminal epidural steroid injection is a common and effective tool for managing lumbar radicular pain, although accidental intravascular injection can rarely result in paralysis. The purpose of this study is to determine the safest needle tip position for computed tomography (CT)-guided lumbar transforaminal epidural steroid injections as determined by incidence of intravascular injection. Methods Three radiologists, in consensus, reviewed procedural imaging for consecutive CT-fluoroscopic lumbar transforaminal epidural steroid injections performed during a 16-month period. Intravascular injections were identified and categorized by needle tip position, vessel type injected, intravascular injection volume and procedural phase containing the intravascular injection. Pearson chi-square and logistic regression testing were used to assess differences between groups, as appropriate. Results Intravascular injections occurred in 9% (52/606) of injections. The intravascular injection rate was significantly lower (P<0.001) for extraforaminal needle position (0%, 0/109) compared to junctional (8%, 27/319) and foraminal (14%, 25/178) needle tip positions. Of the intravascular injections, 4% (2/52) were likely arterial, 35% (18/52) were likely venous, and 62% (32/52) were indeterminate for vessel type injected. 46% (24/52) of intravascular injections were large volume, 33% (17/52) were small volume, and 21% (11/52) were trace volume. 56% (29/52) of intravascular injections occurred with the contrast trial dose, 29% (15/52) with the steroid/analgesic cocktail, and 15% (8/52) with both. Conclusions An extraforaminal needle position for CT-fluoroscopic lumbar transforaminal epidural steroid injections decreases the risk of intravascular injection and therefore may be safer than other needle tip positions. PMID:28097241

Try These Time Management Tips.

ERIC Educational Resources Information Center

Bimrose, Jack J.

1987-01-01

Offers 12 time management tips for harried school administrators, including using a personal calendar, calling five-minute meetings with secretaries, mail-sorting, delegating or declining certain tasks, controlling visitors, screening phone calls, streamlining meetings, and other ideas. (MLH)

47 CFR 215.1 - Background.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

Application of two-dimensional unsteady aerodynamic to a free-tip rotor response analysis

NASA Technical Reports Server (NTRS)

Yates, L.; Kumagai, H.

1985-01-01

The free-tip rotor utilizes a rotor blade tip which is structurally decoupled from the blade inboard section. The tip is free to pitch about its own pitch axis to respond to the local flow angularity changes. The tip also experiences the heaving motion due to the flapping of the rotor blade. For an airfoil in any pitching and heaving motion which can be expanded into a Fourier series, the lift and moment calculated by Theodoren's theory is simply the linear combination of the lift and moment calculated for each harmonic. These lift and moment are then used to determine the response of the free-tip rotor. A parametric study is performed to determine the effect of mechanical damping, mechanical spring, sweep, friction, and a constant control moment on the free-tip rotor response characteristics and the resulting azimuthal lift distributions. The results showed that the free-tip has the capability to suppress the oscillatory lift distribution around the azimuth and to eliminate a significant negative life peak on the advancing tip. This result agrees with the result of the previous analysis based on the steady aerodynamics.

Centering Pregnancy: practical tips for your practice.

PubMed

DeCesare, Julie Z; Jackson, Jessica R

2015-03-01

With increased access to care, current health delivery systems will need expansion to meet higher demands and needs. To define Centering Pregnancy and practical tips for implementation into both private and academic practices. Evidence was gathered through literature reviews. It was found that Centering Pregnancy offers a patient-centered, evidence-based approach to helping with access issues, as well as improving outcomes. This article describes the benefits of Centering Pregnancy to the practice, the provider, and the patient. Practical implementation tips will be offered, with suggestions for negating common implementation barriers.

Needle tip visualization by bevel-point ultrasound generator and prototype photoacoustic imaging system