Sample records for hanger loop drive
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49 CFR 229.99 - Safety hangers.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 49 Transportation 4 2011-10-01 2011-10-01 false Safety hangers. 229.99 Section 229.99..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Internal Combustion Equipment § 229.99 Safety hangers. Drive shafts shall have safety hangers. ...
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49 CFR 229.99 - Safety hangers.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 49 Transportation 4 2010-10-01 2010-10-01 false Safety hangers. 229.99 Section 229.99..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Internal Combustion Equipment § 229.99 Safety hangers. Drive shafts shall have safety hangers. ...
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77 FR 72884 - Steel Wire Garment Hangers From Taiwan
Federal Register 2010, 2011, 2012, 2013, 2014
2012-12-06
... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-1197 (Final)] Steel Wire Garment Hangers... injured by reason of imports of steel wire garment hangers from Taiwan, provided for in subheading 7326.20... notification of a preliminary determination by Commerce that imports of steel wire garment hangers from Taiwan...
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77 FR 9701 - Steel Wire Garment Hangers From Taiwan And Vietnam
Federal Register 2010, 2011, 2012, 2013, 2014
2012-02-17
...)] Steel Wire Garment Hangers From Taiwan And Vietnam Determinations On the basis of the record \\1... injured by reason of imports from Taiwan and Vietnam of steel wire garment hangers, provided for in... the United States at less than fair value (LTFV) and steel wire garment hangers from Vietnam that are...
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Steel pin and hanger assembly replacement options : final report.
DOT National Transportation Integrated Search
2017-01-01
A number of steel beam bridges exist in the United States that contain pin and hanger assemblies. Pin and hanger assemblies are fracture critical members whose failure would result in collapse of the bridge or render it unable to perform its expected...
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77 FR 73424 - Steel Wire Garment Hangers From Taiwan: Antidumping Duty Order
Federal Register 2010, 2011, 2012, 2013, 2014
2012-12-10
... DEPARTMENT OF COMMERCE International Trade Administration [A-583-849] Steel Wire Garment Hangers... ``ITC''), the Department is issuing an antidumping duty order on steel wire garment hangers from Taiwan... antidumping duty investigation of steel wire garment hangers from Taiwan.\\1\\ On November 29, 2012, the ITC...
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Federal Register 2010, 2011, 2012, 2013, 2014
2010-11-09
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... first administrative review of the antidumping duty order on steel wire garment hangers from the People... steel wire garment hangers (``hangers'') from the PRC. See Notice of Antidumping Duty Order: Steel Wire...
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Rate of Hanger Reflex Occurrence: Unexpected Head Rotation on Fronto-temporal Head Compression
ASAHI, Takashi; SATO, Michi; KAJIMOTO, Hiroyuki; KOH, Masaki; KASHIWAZAKI, Daina; KURODA, Satoshi
When the head is encircled with a wire clothes hanger and the unilateral fronto-temporal region is compressed, the head rotates unexpectedly. As the mechanism is unclear, however, we have temporarily named this phenomenon as the “hanger reflex.” We previously reported a case wherein this phenomenon was applied to treat cervical dystonia. Because little is known about this phenomenon, we determined how often this phenomenon is observed in healthy subjects. Study participants were 120 healthy Japanese adults (60 men and 60 women) aged 19–65 years. A wire clothes hanger was applied to each subject’s head. The longer side of the hanger was attached over the volunteer’s fronto-temporal regions on both sides of the head in succession (i.e., two applications per volunteer). We evaluated whether the subjects felt the sensation of head rotation by using a questionnaire. The sensation of head rotation was observed in 95.8% of subjects. There were five non-responders (4.2%). In 85.4% of the trials, head rotation was observed in the direction that coincided with the side compressed by the hanger. There were no differences in responses between genders. The incident rate of the hanger reflex was remarkably high and most likely represents a prevalent phenomenon in humans. The mechanism underlying the reflex remains unknown. Further research should be performed to elucidate the underlying causes of the hanger reflex, which represents a potential treatment for cervical dystonia. PMID:26119894
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-24
... DEPARTMENT OF COMMERCE International Trade Administration [A-552-812] Steel Wire Garment Hangers... preliminary determination in the antidumping duty investigation of steel wire garment hangers from the... withdrawing its participation from this investigation.\\5\\ \\1\\ See Steel Wire Garment Hangers From the...
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Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger
Jiang, Meng; Huang, Cailiang
2014-01-01
The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented. PMID:25045734
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Parametric study on responses of a self-anchored suspension bridge to sudden breakage of a hanger.
Qiu, Wenliang; Jiang, Meng; Huang, Cailiang
2014-01-01
The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-12-10
... DEPARTMENT OF COMMERCE International Trade Administration [C-552-813] Steel Wire Garment Hangers... respect to imports of steel wire garment hangers from the Socialist Republic of Vietnam (Vietnam) with the... Department of Commerce building. \\3\\ See Steel Wire Garment Hangers From the Socialist Republic of Vietnam...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-11-08
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... (``the Department'') is conducting the third administrative review of steel wire garment hangers from the... Wire Garment Hangers From the People's Republic of China: Preliminary Results and Preliminary...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-01-25
... DEPARTMENT OF COMMERCE International Trade Administration [C-552-813] Steel Wire Garment Hangers... countervailing duty (CVD) petition concerning imports of steel wire garment hangers from the Socialist Republic...). See Petition for the Imposition of Antidumping Duties on Steel Wire Garment Hangers from Taiwan and...
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Federal Register 2010, 2011, 2012, 2013, 2014
2013-11-25
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... the antidumping duty order on steel wire garment hangers from the People's Republic of China (``PRC... comment on these preliminary results. \\1\\ See Notice of Antidumping Duty Order: Steel Wire Garment Hangers...
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Federal Register 2010, 2011, 2012, 2013, 2014
2013-02-05
... DEPARTMENT OF COMMERCE International Trade Administration [A-552-812] Steel Wire Garment Hangers...''), the Department is issuing an antidumping duty order on steel wire garment hangers from the Socialist... investigation of steel wire garment hangers from Vietnam.\\1\\ On January 28, 2013, pursuant to section 735(d) of...
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Coat Hangers across the Curriculum
ERIC Educational Resources Information Center
Kibble, Bob
2012-01-01
There are many ways in which wire coat hangers can be used other than for suspending clothes. The author has been making use of them in his teaching for many years--copying ideas from colleagues and creating some for himself. In this article, he shares five examples that can enrich learning about science. (Contains 6 figures.)
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Theoretical analysis of HVAC duct hanger systems
NASA Technical Reports Server (NTRS)
Miller, R. D.
1987-01-01
Several methods are presented which, together, may be used in the analysis of duct hanger systems over a wide range of frequencies. The finite element method (FEM) and component mode synthesis (CMS) method are used for low- to mid-frequency range computations and have been shown to yield reasonably close results. The statistical energy analysis (SEA) method yields predictions which agree with the CMS results for the 800 to 1000 Hz range provided that a sufficient number of modes participate. The CMS approach has been shown to yield valuable insight into the mid-frequency range of the analysis. It has been demonstrated that it is possible to conduct an analysis of a duct/hanger system in a cost-effective way for a wide frequency range, using several methods which overlap for several frequency bands.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-07-11
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... administrative review of the antidumping duty order on steel wire garment hangers from the People's Republic of... the Secretary of Commerce ``Third Administrative Review of Steel Wire Garment Hangers from China...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-12-26
... DEPARTMENT OF COMMERCE International Trade Administration [A-552-812] Steel Wire Garment Hangers... less than fair value (``LTFV'') in the antidumping investigation of steel wire garment hangers from the... Determination of sales at LTFV. We continue to determine that steel wire garment hangers from Vietnam are being...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-11-28
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... for a new shipper review (``NSR'') of the antidumping duty order on steel wire garment hangers from... antidumping duty order on steel wire garment hangers from the PRC (``the Order'') was published on October 6...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-22
...)] Steel Wire Garment Hangers From Taiwan and Vietnam; (Corrected Notice) Scheduling of the Final Phase of... the United States is materially retarded, by reason of subsidized imports from Vietnam of steel wire garment hangers and less- than-fair-value imports from Taiwan and Vietnam of steel wire garment hangers...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-20
...)] Steel Wire Garment Hangers From Taiwan and Vietnam; Scheduling of the Final Phase of Countervailing Duty... States is materially retarded, by reason of subsidized imports from Taiwan of steel wire garment hangers and less- than-fair-value imports from Taiwan and Vietnam of steel wire garment hangers, provided for...
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Interior view of northeast unit master bedroom, looking into sleeping ...
Interior view of northeast unit master bedroom, looking into sleeping porch, facing northeast - MacDill Air Force Base, Double Non-Commissioned Officers' Quarters, 7418 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-05-13
... of Steel Wire Garment Hangers From the People's Republic of China: Final Results and Final Partial... antidumping duty order on steel wire garment hangers from the People's Republic of China (``PRC'').\\1\\ We gave... period of review (``POR''), March 25, 2008, through November 30, 2009. \\1\\ See Steel Wire Garment Hangers...
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Federal Register 2010, 2011, 2012, 2013, 2014
2013-05-16
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... review of the antidumping duty order on steel wire garment hangers from the People's Republic of China..., 2010, through September 30, 2011. \\1\\ See Steel Wire Garment Hangers from the People's Republic of...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-03-30
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... results of the second administrative review of the antidumping duty order on steel wire garment hangers... not change the current rates of any other parties. \\1\\ See Steel Wire Garment Hangers From the People...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-03-01
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... duty order \\1\\ on steel wire garment hangers from the People's Republic of China (``PRC'').\\2\\ We gave... Duty Order: Steel Wire Garment Hangers From the People's Republic of China, 73 FR 58111 (October 6...
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Rugh, J. P.
2013-07-01
Plug-in hybrid electric vehicles and electric vehicles have increased vehicle thermal management complexity, using separate coolant loop for advanced power electronics and electric motors. Additional thermal components result in higher costs. Multiple cooling loops lead to reduced range due to increased weight. Energy is required to meet thermal requirements. This presentation for the 2013 Annual Merit Review discusses integrated vehicle thermal management by combining fluid loops in electric drive vehicles.
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24 CFR 3280.608 - Hangers and supports.
Code of Federal Regulations, 2010 CFR
2010-04-01
... Hangers and supports. (a) Strains and stresses. Piping in a plumbing system shall be installed without undue strains and stresses, and provision shall be made for expansion, contraction, and structural..., plastic drainage piping shall be supported at intervals not to exceed 4 feet and plastic water piping...
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24 CFR 3280.608 - Hangers and supports.
Code of Federal Regulations, 2011 CFR
2011-04-01
... Hangers and supports. (a) Strains and stresses. Piping in a plumbing system shall be installed without undue strains and stresses, and provision shall be made for expansion, contraction, and structural..., plastic drainage piping shall be supported at intervals not to exceed 4 feet and plastic water piping...
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Clothing hanger injuries: pediatric head and neck traumas in the United States, 2002-2012.
Walls, Andrew; Pierce, Matthew; Wang, Hongkun; Harley, Earl H
2014-02-01
To discuss pediatric clothing hanger injuries and review the National Electronic Injury Surveillance System to elucidate frequency and promote increased public awareness among pediatric otolaryngologists. Cross-sectional analysis of a national database. National Electronic Injury Surveillance System Database. A retrospective review of the National Electronic Injury Surveillance System provided a nationally weighted sampling estimate of 394 pediatric incident reports involving clothing hangers. Each incident report was analyzed for impalement, facial laceration, and contusion injuries to the mouth, face, and head. In addition, hospital disposition and location of the described incident were also obtained. Upon review of the National Electronic Injury Surveillance System, incident rates of pediatric oral impalement (95% confidence interval [CI], 0.10-0.41), facial laceration (95% CI, 0.22-0.41), and facial abrasion injuries (95% CI, 0.15-0.44) frequently involved the metal clothing hanger design. In addition, most of the reported injuries occurred within the home and involved lacerations to the oral cavity. This is the first multiyear, nationally representative study to analyze clothing hanger injuries in the pediatric population. We demonstrate that these injuries occur more frequently than the medical literature currently reports and also elucidate that children are more likely to obtain laceration injuries by metal clothing hangers within the home. Furthermore, we provide a recommendation for standardization of the National Electronic Injury Surveillance System such that product safety analysis may occur and reduce further pediatric incidents.
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Federal Register 2010, 2011, 2012, 2013, 2014
2010-04-30
... Administrative Review of Steel Wire Hangers From the People's Republic of China: Extension of Time Limit for the... the antidumping duty order on steel wire garment hangers from the People's Republic of China (``PRC...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-01-06
... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-487 and 731-TA-1197-1198 (Preliminary)] Steel Wire Garment Hangers From Taiwan and Vietnam; Institution of Antidumping and Countervailing Duty... Vietnam of steel wire garment hangers, provided for in subheading 7326.20 of the Harmonized Tariff...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-03-08
... DEPARTMENT OF COMMERCE International Trade Administration [C-552-813] Steel Wire Garment Hangers From the Socialist Republic of Vietnam: Notice of Postponement of Preliminary Determination in the... investigation of steel wire garment hangers from the Socialist Republic of Vietnam. See Steel Wire Garment...
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-03-18
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers From the People's Republic of China: Partial Rescission of Antidumping Duty Administrative Review... administrative review of the antidumping duty order on steel wire garment hangers from the People's Republic of...
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Federal Register 2010, 2011, 2012, 2013, 2014
2013-02-05
... DEPARTMENT OF COMMERCE International Trade Administration [C-552-813] Certain Steel Wire Garment... Department is issuing a countervailing duty order on certain steel wire garment hangers from the Socialist... its final determination in the countervailing duty investigation of certain steel wire garment hangers...
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Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-22
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers...-circumvention inquiry to determine whether certain imports of steel wire garment hangers from the Socialist Republic of Vietnam (``Vietnam'') are circumventing the antidumping duty order on steel wire garment...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-05-14
... DEPARTMENT OF COMMERCE International Trade Administration [A-552-812, A-583-849] Steel Wire... investigations of steel wire garment hangers from the Socialist Republic of Vietnam (``Vietnam'') and Taiwan.\\1...\\ See Steel Wire Garment Hangers From the Socialist Republic of Vietnam and Taiwan: Initiation of...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-01-25
... DEPARTMENT OF COMMERCE International Trade Administration [A-552-812, A-583-849] Steel Wire...'') petition concerning imports of steel wire garment hangers from Vietnam and Taiwan filed in proper form on..., as amended (the ``Act''), Petitioners allege that imports of steel wire garment hangers from Vietnam...
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-05-14
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... International Trade Compliance Analyst, Office 9, regarding Third Administrative Review of Steel Wire Garment..., Import Administration; regarding the Antidumping Duty Administrative Review of Steel Garment Wire Hangers...
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1. Overview of Building 1015 (land plane hanger), looking east ...
1. Overview of Building 1015 (land plane hanger), looking east - Naval Air Station Chase Field, Building 1015, Byrd Street, .82 mile South-southeast of intersection of Texas State Highway 202 & Independence Street, Beeville, Bee County, TX
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-05-19
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... administrative review of the antidumping duty order on steel wire garment hangers from the People's Republic of... Trade Compliance Analyst, Office 9, regarding the Second Administrative Review of Steel Wire Garment...
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Parameters of loop-controlled magnetic rheology drive for segmented large mirror
NASA Astrophysics Data System (ADS)
Deulin, Eugeni A.; Mikhailov, Valeri P.; Eliseev, Oleg N.; Sytchev, Victor V.
2000-07-01
The design, parameters and the amplitude-frequency analysis of the new magnetic rheology (MR) drive are presented. The combination of hydrostatic carrier, MR hydraulic loop control, elastic thin wall seal joined in a single unit ensures small positioning error nm and small time of response T
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Photocopy of drawing (original drawing of Photographic Laboratory Building in ...
Photocopy of drawing (original drawing of Photographic Laboratory Building in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) PLANS - MacDill Air Force Base, Photographic Laboratory, 7718 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-01-07
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers From the People's Republic of China: Extension of Time Limit for Final Results of the Antidumping Duty...'') published the preliminary results of this administrative review. See Steel Wire Garment Hangers From the...
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Photocopy of drawing (original blueprint of Special Type Service Station ...
Photocopy of drawing (original blueprint of Special Type Service Station in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1941 architectural drawings by Standard Oil Company Engineering Department of Louisville, KY) ELEVATIONS & SECTION - MacDill Air Force Base, Service Station, 7303 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original blueprint of Special Type Service Station ...
Photocopy of drawing (original blueprint of Special Type Service Station in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1941 architectural drawings by Standard Oil Company Engineering Department of Louisville, KY) PLAN - MacDill Air Force Base, Service Station, 7303 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original blueprint of Special Type Service Station ...
Photocopy of drawing (original blueprint of Special Type Service Station in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1941 architectural drawings by Standard Oil Company Engineering Department of Louisville, KY) SITE PLAN - MacDill Air Force Base, Service Station, 7303 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Signal & Ordnance Warehouse ...
Photocopy of drawing (original drawing of Signal & Ordnance Warehouse in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General)TRUSS DETAILS - MacDill Air Force Base, Signal & Ordnance Warehouse, 7620 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Signal & Ordnance Warehouse ...
Photocopy of drawing (original drawing of Signal & Ordnance Warehouse in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General) SECTIONS AND DETAILS - MacDill Air Force Base, Signal & Ordnance Warehouse, 7620 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Photographic Laboratory Building in ...
Photocopy of drawing (original drawing of Photographic Laboratory Building in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) MAIN ENTRANCE DETAILS - MacDill Air Force Base, Photographic Laboratory, 7718 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of PaintOil & Dope Building ...
Photocopy of drawing (original drawing of Paint-Oil & Dope Building in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General) DETAILS - MacDill Air Force Base, Paint, Oil & Dope Building, 7716 Hanger Loop Drive, Tampa, Hillsborough County, FL
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78 FR 7452 - Steel Wire Garment Hangers From Vietnam; Determinations
Federal Register 2010, 2011, 2012, 2013, 2014
2013-02-01
... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-487 and 731-TA-1198 (Final)] Steel Wire...), that an industry in the United States is materially injured by reason of imports of steel wire garment... duty orders on steel wire garment hangers from Vietnam. Background The Commission instituted these...
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Astronaut Walter Schirra leaves Hanger "S" prior to MA-8 flight
1963-12-01
S63-00695 (3 Oct. 1962) --- Astronaut Walter M. Schirra Jr., pilot of the Mercury-Atlas 8 (MA-8) Earth-orbital spaceflight, leaves Hanger "S" at Cape Canaveral on his way to his scheduled Oct. 3, 1962 flight. Photo credit: NASA
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U.S. Marine Corps Air Facility, Santa Ana, California hangers no. ...
U.S. Marine Corps Air Facility, Santa Ana, California hangers no. 1&2-building no. 28 &29. Drawing no. PW-66-044 - Marine Corps Air Station Tustin, Northern Lighter Than Air Ship Hangar, Meffett Avenue & Maxfield Street, Tustin, Orange County, CA
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U.S. Marine Corps Air Facility, Santa Ana, California hangers no. ...
U.S. Marine Corps Air Facility, Santa Ana, California hangers no. 1&2-building no. 28 &29. Drawing no. PW-66-044 - Marine Corps Air Station Tustin, East of Red Hill Avenue between Edinger Avenue & Barranca Parkway, Tustin, Orange County, CA
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Photocopy of drawing (original drawing of PaintOil & Dope Building ...
Photocopy of drawing (original drawing of Paint-Oil & Dope Building in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General) PLAN AND ELEVATIONS - MacDill Air Force Base, Paint, Oil & Dope Building, 7716 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Signal & Ordnance Warehouse ...
Photocopy of drawing (original drawing of Signal & Ordnance Warehouse in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General) PLANS, ELEVATIONS, SECTIONS AND DETAILS - MacDill Air Force Base, Signal & Ordnance Warehouse, 7620 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Double N.C.O. Quarters in ...
Photocopy of drawing (original drawing of Double N.C.O. Quarters in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) INTERIOR DETAILS - MacDill Air Force Base, Double Non-Commissioned Officers' Quarters, 7418 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Q.M. Gas & Oil ...
Photocopy of drawing (original drawing of Q.M. Gas & Oil House in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General) ELEVATIONS AND DETAILS - MacDill Air Force Base, Quartermaster Gas & Oil House, 8103 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Double N.C.O. Quarters in ...
Photocopy of drawing (original drawing of Double N.C.O. Quarters in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) ELEVATIONS AND SECTION - MacDill Air Force Base, Double Non-Commissioned Officers' Quarters, 7418 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Photographic Laboratory Building in ...
Photocopy of drawing (original drawing of Photographic Laboratory Building in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) FRONT AND RIGHT SIDE ELEVATIONS AND SECTIONS - MacDill Air Force Base, Photographic Laboratory, 7718 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Photographic Laboratory Building in ...
Photocopy of drawing (original drawing of Photographic Laboratory Building in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) REAR AND LEFT SIDE ELEVATIONS AND SECTIONS - MacDill Air Force Base, Photographic Laboratory, 7718 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Armament & Instrument Inspection ...
Photocopy of drawing (original drawing of Armament & Instrument Inspection and Adjustment Bldg. in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1941 architectural drawings by Construction Division, Office of the Quartermaster General) FIRST FLOOR PLAN, SECTIONS, AND DETAILS - MacDill Air Force Base, Armament & Instrument Inspection & Adjustment Building, 7807 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Armament & Instrument Inspection ...
Photocopy of drawing (original drawing of Armament & Instrument Inspection and Adjustment Bldg. in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1941 architectural drawings by Construction Division, Office of the Quartermaster General) ELEVATIONS AND DETAILS - MacDill Air Force Base, Armament & Instrument Inspection & Adjustment Building, 7807 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Armament & Instrument Inspection ...
Photocopy of drawing (original drawing of Armament & Instrument Inspection and Adjustment Bldg. in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1941 architectural drawings by Construction Division, Office of the Quartermaster General) ELEVATIONS AND SECTIONS - MacDill Air Force Base, Armament & Instrument Inspection & Adjustment Building, 7807 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Photocopy of drawing (original drawing of Double N.C.O. Quarters in ...
Photocopy of drawing (original drawing of Double N.C.O. Quarters in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1939 architectural drawings by Construction Division, Office of the Quartermaster General) FIRST AND SECOND FLOOR PLANS - MacDill Air Force Base, Double Non-Commissioned Officers' Quarters, 7418 Hanger Loop Drive, Tampa, Hillsborough County, FL
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-05-10
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-918] Steel Wire Garment Hangers... Administration, Department of Commerce. Preliminary Determination We preliminarily determine that steel wire... Act of 1930, as amended (``the Act''). See Notice of Antidumping Duty Order: Steel Wire Garment...
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Mechanical-thermal noise in drive-mode of a silicon micro-gyroscope.
Yang, Bo; Wang, Shourong; Li, Hongsheng; Zhou, Bailing
2009-01-01
A new closed-loop drive scheme which decouples the phase and the gain of the closed-loop driving system was designed in a Silicon Micro-Gyroscope (SMG). We deduce the system model of closed-loop driving and use stochastic averaging to obtain an approximate "slow" system that clarifies the effect of thermal noise. The effects of mechanical-thermal noise on the driving performance of the SMG, including the noise spectral density of the driving amplitude and frequency, are derived. By calculating and comparing the noise amplitude due to thermal noise both in the opened-loop driving and in the closed-loop driving, we find that the closed-loop driving does not reduce the RMS noise amplitude. We observe that the RMS noise frequency can be reduced by increasing the quality factor and the drive amplitude in the closed-loop driving system. The experiment and simulation validate the feasibility of closed-loop driving and confirm the validity of the averaged equation and its stablility criterion. The experiment and simulation results indicate the electrical noise of closed-loop driving circuitry is bigger than the mechanical-thermal noise and as the driving mass decreases, the mechanical-thermal noise may get bigger than the electrical noise of the closed-loop driving circuitry.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-12-26
... DEPARTMENT OF COMMERCE International Trade Administration [C-552-813] Certain Steel Wire Garment...) determines that countervailable subsidies are being provided to producers and exporters of steel wire garment... Companies). \\1\\ See Steel Wire Garment Hangers From the Socialist Republic of Vietnam: Initiation of...
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A right-handed signalling pathway drives heart looping in vertebrates
Ocaña, Oscar H.; Coskun, Hakan; Minguillón, Carolina; Murawala, Prayag; Tanaka, Elly M.; Galcerán, Joan; Muñoz-Chapuli, Ramón; Nieto, M. Angela
2017-01-01
The majority of animals show external bilateral symmetry, precluding the observation of multiple internal left-right (L/R) asymmetries that are fundamental for organ packaging and function1,2. In vertebrates, left identity is mediated by the left-specific Nodal-Pitx2 axis that is repressed on the right-hand side by the epithelial-mesenchymal transition (EMT) inducer Snail13,4. Despite some existing evidence3,5, it remains unclear whether an equivalent instructive pathway provides right-hand specific information to the embryo. Here we show that in zebrafish, BMP mediates the L/R asymmetric activation of another EMT inducer, Prrx1a, in the lateral plate mesoderm (LPM) with higher levels on the right. Prrx1a drives L/R differential cell movements towards the midline leading to a leftward displacement of the cardiac posterior pole through an actomyosin-dependent mechanism. Downregulation of Prrx1a prevents heart looping and leads to mesocardia. Two parallel and mutually repressed pathways, respectively driven by Nodal and BMP on the left and right LPM, converge on the asymmetric activation of Pitx2 and Prrx1, two transcription factors that integrate left and right information to govern heart morphogenesis. This mechanism is conserved in the chicken embryo and, in the mouse, Snail1 fulfills the role played by Prrx1 in fish and chick. Thus, a differential L/R EMT produces asymmetric cell movements and forces, more prominent from the right, that drive heart laterality in vertebrates. PMID:28880281
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NASA Technical Reports Server (NTRS)
Tiwari, Sanjiv K.; Thalmann, Julia K.; Panesar, Navdeep K.; Moore, Ronald L.; Winebarger, Amy R.
2017-01-01
Coronal heating generally increases with increasing magnetic field strength: the EUV/X-ray corona in active regions is 10--100 times more luminous and 2--4 times hotter than that in quiet regions and coronal holes, which are heated to only about 1.5 MK, and have fields that are 10--100 times weaker than that in active regions. From a comparison of a nonlinear force-free model of the three-dimensional active region coronal field to observed extreme-ultraviolet loops, we find that (1) umbra-to-umbra coronal loops, despite being rooted in the strongest magnetic flux, are invisible, and (2) the brightest loops have one foot in an umbra or penumbra and the other foot in another sunspot's penumbra or in unipolar or mixed-polarity plage. The invisibility of umbra-to-umbra loops is new evidence that magnetoconvection drives solar-stellar coronal heating: evidently, the strong umbral field at both ends quenches the magnetoconvection and hence the heating. Our results from EUV observations and nonlinear force-free modeling of coronal magnetic field imply that, for any coronal loop on the Sun or on any other convective star, as long as the field can be braided by convection in at least one loop foot, the stronger the field in the loop, the stronger the coronal heating.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-10-15
... antidumping duty investigation of hangers from Taiwan.\\1\\ No interested party provided case briefs or rebuttal... others rate is a simple average of these values, which is 69.98 percent.\\5\\ \\5\\ See Initiation Checklist... 10, 2012) (where the Department determined the all others rate using a simple average). Disclosure We...
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Were they in the loop during automated driving? Links between visual attention and crash potential.
Louw, Tyron; Madigan, Ruth; Carsten, Oliver; Merat, Natasha
2017-08-01
A proposed advantage of vehicle automation is that it relieves drivers from the moment-to-moment demands of driving, to engage in other, non-driving related, tasks. However, it is important to gain an understanding of drivers' capacity to resume manual control, should such a need arise. As automation removes vehicle control-based measures as a performance indicator, other metrics must be explored. This driving simulator study, conducted under the European Commission (EC) funded AdaptIVe project, assessed drivers' gaze fixations during partially-automated (SAE Level 2) driving, on approach to critical and non-critical events. Using a between-participant design, 75 drivers experienced automation with one of five out-of-the-loop (OOTL) manipulations, which used different levels of screen visibility and secondary tasks to induce varying levels of engagement with the driving task: 1) no manipulation, 2) manipulation by light fog, 3) manipulation by heavy fog, 4) manipulation by heavy fog plus a visual task, 5) no manipulation plus an n-back task. The OOTL manipulations influenced drivers' first point of gaze fixation after they were asked to attend to an evolving event. Differences resolved within one second and visual attention allocation adapted with repeated events, yet crash outcome was not different between OOTL manipulation groups. Drivers who crashed in the first critical event showed an erratic pattern of eye fixations towards the road centre on approach to the event, while those who did not demonstrated a more stable pattern. Automated driving systems should be able to direct drivers' attention to hazards no less than 6 seconds in advance of an adverse outcome. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
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Microgyroscope with closed loop output
NASA Technical Reports Server (NTRS)
Challoner, A. Dorian (Inventor); Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor); Cargille, Donald R. (Inventor)
2002-01-01
A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.
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Linear motor drive system for continuous-path closed-loop position control of an object
Barkman, William E.
1980-01-01
A precision numerical controlled servo-positioning system is provided for continuous closed-loop position control of a machine slide or platform driven by a linear-induction motor. The system utilizes filtered velocity feedback to provide system stability required to operate with a system gain of 100 inches/minute/0.001 inch of following error. The filtered velocity feedback signal is derived from the position output signals of a laser interferometer utilized to monitor the movement of the slide. Air-bearing slides mounted to a stable support are utilized to minimize friction and small irregularities in the slideway which would tend to introduce positioning errors. A microprocessor is programmed to read command and feedback information and converts this information into the system following error signal. This error signal is summed with the negative filtered velocity feedback signal at the input of a servo amplifier whose output serves as the drive power signal to the linear motor position control coil.
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Pattison, Jillian M.; Wright, Jason B.; Cole, Michael D.
2015-01-01
The majority of the genome consists of intergenic and non-coding DNA sequences shown to play a major role in different gene regulatory networks. However, the specific potency of these distal elements as well as how these regions exert function across large genomic distances remains unclear. To address these unresolved issues, we closely examined the chromatin architecture around proto-oncogenic loci in the mouse and human genomes to demonstrate a functional role for chromatin looping in distal gene regulation. Using cell culture models, we show that tumorigenic retroviral integration sites within the mouse genome occur near existing large chromatin loops and that this chromatin architecture is maintained within the human genome as well. Significantly, as mutagenesis screens are not feasible in humans, we demonstrate a way to leverage existing screens in mice to identify disease relevant human enhancers and expose novel disease mechanisms. For instance, we characterize the epigenetic landscape upstream of the human Cyclin D1 locus to find multiple distal interactions that contribute to the complex cis-regulation of this cell cycle gene. Furthermore, we characterize a novel distal interaction upstream of the Cyclin D1 gene which provides mechanistic evidence for the abundant overexpression of Cyclin D1 occurring in multiple myeloma cells harboring a pathogenic translocation event. Through use of mapped retroviral integrations and translocation breakpoints, our studies highlight the importance of chromatin looping in oncogene expression, elucidate the epigenetic mechanisms crucial for distal cis-regulation, and in one particular instance, explain how a translocation event drives tumorigenesis through upregulation of a proto-oncogene. PMID:25799187
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Two-motor direct drive control for elevation axis of telescope
NASA Astrophysics Data System (ADS)
Tang, T.; Tan, Y.; Ren, G.
2014-07-01
Two-motor application has become a very attractive filed in important field which high performance is permitted to achieve of position, speed, and acceleration. In the elevation axis of telescope control system, two-motor direct drive is proposed to enhance the high performance of tracking control system. Although there are several dominant strengths such as low size of motors and high torsional structural dynamics, the synchronization control of two motors is a very difficult and important. In this paper, a multi-loop control technique base master-slave current control is used to synchronize two motors, including current control loop, speed control loop and position control loop. First, the direct drive function of two motors is modeled. Compared of single motor direct control system, the resonance frequency of two motor control systems is same; while the anti-resonance frequency of two motors control system is 1.414 times than those of sing motor system. Because of rigid coupling for direct drive, the speed of two motor of the system is same, and the synchronization of torque for motors is critical. The current master-slave control technique is effective to synchronize the torque, which the current loop of the master motors is tracked the other slave motor. The speed feedback into the input of current loop of the master motors. The experiments test the performance of the two motors drive system. The random tracking error is 0.0119" for the line trajectory of 0.01°/s.
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A Nodal-independent and tissue-intrinsic mechanism controls heart-looping chirality
NASA Astrophysics Data System (ADS)
Noël, Emily S.; Verhoeven, Manon; Lagendijk, Anne Karine; Tessadori, Federico; Smith, Kelly; Choorapoikayil, Suma; den Hertog, Jeroen; Bakkers, Jeroen
2013-11-01
Breaking left-right symmetry in bilateria is a major event during embryo development that is required for asymmetric organ position, directional organ looping and lateralized organ function in the adult. Asymmetric expression of Nodal-related genes is hypothesized to be the driving force behind regulation of organ laterality. Here we identify a Nodal-independent mechanism that drives asymmetric heart looping in zebrafish embryos. In a unique mutant defective for the Nodal-related southpaw gene, preferential dextral looping in the heart is maintained, whereas gut and brain asymmetries are randomized. As genetic and pharmacological inhibition of Nodal signalling does not abolish heart asymmetry, a yet undiscovered mechanism controls heart chirality. This mechanism is tissue intrinsic, as explanted hearts maintain ex vivo retain chiral looping behaviour and require actin polymerization and myosin II activity. We find that Nodal signalling regulates actin gene expression, supporting a model in which Nodal signalling amplifies this tissue-intrinsic mechanism of heart looping.
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NASA Astrophysics Data System (ADS)
Hassan Mohammed, Mohammed Ahmed
For an efficient maintenance of a diverse fleet of air- and rotorcraft, effective condition based maintenance (CBM) must be established based on rotating components monitored vibration signals. In this dissertation, we present theory and applications of polyspectral signal processing techniques for condition monitoring of critical components in the AH-64D helicopter tail rotor drive train system. Currently available vibration-monitoring tools are mostly built around auto- and cross-power spectral analysis which have limited performance in detecting frequency correlations higher than second order. Studying higher order correlations and their Fourier transforms, higher order spectra, provides more information about the vibration signals which helps in building more accurate diagnostic models of the mechanical system. Based on higher order spectral analysis, different signal processing techniques are developed to assess health conditions of different critical rotating-components in the AH-64D helicopter drive-train. Based on cross-bispectrum, quadratic nonlinear transfer function is presented to model second order nonlinearity in a drive-shaft running between the two hanger bearings. Then, quadratic-nonlinearity coupling coefficient between frequency harmonics of the rotating shaft is used as condition metric to study different seeded shaft faults compared to baseline case, namely: shaft misalignment, shaft imbalance, and combination of shaft misalignment and imbalance. The proposed quadratic-nonlinearity metric shows better capabilities in distinguishing the four studied shaft settings than the conventional linear coupling based on cross-power spectrum. We also develop a new concept of Quadratic-Nonlinearity Power-Index spectrum, QNLPI(f), that can be used in signal detection and classification, based on bicoherence spectrum. The proposed QNLPI(f) is derived as a projection of the three-dimensional bicoherence spectrum into two-dimensional spectrum that
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Louw, Tyron; Markkula, Gustav; Boer, Erwin; Madigan, Ruth; Carsten, Oliver; Merat, Natasha
2017-11-01
This driving simulator study, conducted as part of the EU AdaptIVe project, investigated drivers' performance in critical traffic events, during the resumption of control from an automated driving system. Prior to the critical events, using a between-participant design, 75 drivers were exposed to various screen manipulations that varied the amount of available visual information from the road environment and automation state, which aimed to take them progressively further 'out-of-the-loop' (OoTL). The current paper presents an analysis of the timing, type, and rate of drivers' collision avoidance response, also investigating how these were influenced by the criticality of the unfolding situation. Results showed that the amount of visual information available to drivers during automation impacted on how quickly they resumed manual control, with less information associated with slower take-over times, however, this did not influence the timing of when drivers began a collision avoidance manoeuvre. Instead, the observed behaviour is in line with recent accounts emphasising the role of scenario kinematics in the timing of driver avoidance response. When considering collision incidents in particular, avoidance manoeuvres were initiated when the situation criticality exceeded an Inverse Time To Collision value of ≈0.3s -1 . Our results suggest that take-over time and timing and quality of avoidance response appear to be largely independent, and while long take-over time did not predict collision outcome, kinematically late initiation of avoidance did. Hence, system design should focus on achieving kinematically early avoidance initiation, rather than short take-over times. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Electron acceleration and radiation signatures in loop coronal transients
NASA Technical Reports Server (NTRS)
Vlahos, L.; Gergely, T. E.; Papadopoulos, K.
1982-01-01
It is proposed that in loop coronal transients an erupting loop moves away from the solar surface, with a velocity exceeding the local Alfven speed, pushing against the overlying magnetic fields and driving a shock in the front of the moving part of the loop. Lower hybrid waves are excited at the shock front and propagate radially toward the center of the loop with phase velocity along the magnetic field that exceeds the thermal velocity. The lower hybrid waves stochastically accelerate the tail of the electron distribution inside the loop. The manner in which the accelerated electrons are trapped in the moving loop are discussed, and their radiation signature is estimated. It is suggested that plasma radiation can explain the power observed in stationary and moving type IV bursts.
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Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids
Jaafar, Miriam; Cuenca, Mariano; Melcher, John; Raman, Arvind
2012-01-01
Summary We introduce drive-amplitude-modulation atomic force microscopy as a dynamic mode with outstanding performance in all environments from vacuum to liquids. As with frequency modulation, the new mode follows a feedback scheme with two nested loops: The first keeps the cantilever oscillation amplitude constant by regulating the driving force, and the second uses the driving force as the feedback variable for topography. Additionally, a phase-locked loop can be used as a parallel feedback allowing separation of the conservative and nonconservative interactions. We describe the basis of this mode and present some examples of its performance in three different environments. Drive-amplutide modulation is a very stable, intuitive and easy to use mode that is free of the feedback instability associated with the noncontact-to-contact transition that occurs in the frequency-modulation mode. PMID:22563531
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Feasibility study of a discrete bearing/roller drive rotary joint for the space station
NASA Technical Reports Server (NTRS)
Loewenthal, S. H.; Schuller, F. T.
1986-01-01
The most critical mechanism on board the proposed space station is the continously rotating joint which must accurately align the solar power units with the sun during earth orbit. The feasibility of a multiple, discrete bearing supported joint driven by a self-loading, pinch drive actuator was investigated for this application. This concept appears to offer greater protection against catastrophic jamming, less sensitivity to adverse thermal gradients, greater accessibility to inorbit servicing or replacement and greater adaptability to very large (5 m) truss members than to more conventional continuous support bearing/gear reducer joints. Analytical trade studies performed herein establish that a discrete cam roller bearing support system having eight hangers around a continuous ring would provide sufficient radial and bending stiffness to prevent any degradation in the fundamental frequencies of the solar wing structure. Furthermore, it appears that the pinch roller drive mechanism can be readily sized to meet or exceed system performance and service life requirements. Wear life estimates based on experimental data for a steel roller coated with an advanced polyimide film show a continuous service life more than two orders of magnitude greater than required for this application.
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An interacting loop model of solar flare bursts
NASA Technical Reports Server (NTRS)
Emslie, A. G.
1981-01-01
As a result of the strong heating produced at chromospheric levels during a solar flare burst, the local gas pressure can transiently attain very large values in certain regions. The effectiveness of the surrounding magnetic field at confining this high pressure plasma is therefore reduced and the flaring loop becomes free to expand laterally. In so doing it may drive magnetic field lines into neighboring, nonflaring, loops in the same active region, causing magnetic reconnection to take place and triggering another flare burst. The features of this interacting loop model are found to be in good agreement with the energetics and time structure of flare associated solar hard X-ray bursts.
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Modeling of Autovariator Operation as Power Components Adjuster in Adaptive Machine Drives
NASA Astrophysics Data System (ADS)
Balakin, P. D.; Belkov, V. N.; Shtripling, L. O.
2018-01-01
Full application of the available power and stationary mode preservation for the power station (engine) operation of the transport machine under the conditions of variable external loading, are topical issues. The issues solution is possible by means of mechanical drives with the autovaried rate transfer function and nonholonomic constraint of the main driving mediums. Additional to the main motion, controlled motion of the driving mediums is formed by a variable part of the transformed power flow and is implemented by the integrated control loop, functioning only on the basis of the laws of motion. The mathematical model of the mechanical autovariator operation is developed using Gibbs function, acceleration energy; the study results are presented; on their basis, the design calculations of the autovariator driving mediums and constraints, including its automatic control loop, are possible.
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THE INSTABILITY AND NON-EXISTENCE OF MULTI-STRANDED LOOPS WHEN DRIVEN BY TRANSVERSE WAVES
DOE Office of Scientific and Technical Information (OSTI.GOV)
Magyar, N.; Van Doorsselaere, T., E-mail: norbert.magyar@wis.kuleuven.be
2016-06-01
In recent years, omni-present transverse waves have been observed in all layers of the solar atmosphere. Coronal loops are often modeled as a collection of individual strands in order to explain their thermal behavior and appearance. We perform three-dimensional (3D) ideal magnetohydrodynamics simulations to study the effect of a continuous small amplitude transverse footpoint driving on the internal structure of a coronal loop composed of strands. The output is also converted into synthetic images, corresponding to the AIA 171 and 193 Å passbands, using FoMo. We show that the multi-stranded loop ceases to exist in the traditional sense of themore » word, because the plasma is efficiently mixed perpendicularly to the magnetic field, with the Kelvin–Helmholtz instability acting as the main mechanism. The final product of our simulation is a mixed loop with density structures on a large range of scales, resembling a power-law. Thus, multi-stranded loops are unstable to driving by transverse waves, and this raises strong doubts on the usability and applicability of coronal loop models consisting of independent strands.« less
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NASA Astrophysics Data System (ADS)
Lee, Tzuo-Chang; Chen, Di
1987-01-01
We present in this paper an overview of Optotech's 5984 Optical Disk Drive. Key features such as the modulation code, the disk format, defect mapping scheme and the optical head and servo subsystem will be singled out for discussion. Description of Optotech's 5984 disk drive The Optotech 5984 optical disk drive is a write-once-read-mostly (WORM) rotating optical memory with 200 Megabyte capacity on each side of the disk. It has a 5 1/4 inch form factor that will fit into any personal computer full-height slot. The drive specification highlights are given in Table 1. A perspective view of the drive mechanical assembly is shown in Figure 1. The spindle that rotates the disk has a runout of less than 10 um. The rotational speed at 1200 revolutions per minute (rpm) is held to an accuracy of 10-3. The total angular tolerance from perfect perpendicular alignment between the rotating disk and the incident optical beam axis is held to less than 17 milliradians. The coarse seek is accomplished through a stepping motor driving the optical head with 1.3 milliseconds per step or 32 tracks per step. The analog channels including read/write, the phase lock loop and the servo loops for focus and track control are contained on one surface mount pc board while the digital circuitry that interfaces with the drive and the controller is on a separate pc board. A microprocessor 8039 is used to control the handshake and the sequence of R/W commands. A separate power board is used to provide power to the spindle and the stepping motors. In the following we will discuss some of the salient features in the drive and leave the details to three accompanying Optotech papers. These salient features are derived from a design that is driven by three major considerations. One is precise control of the one micron diameter laser spot to any desired location on the disk. The second consideration is effective management of media defects. Given the state of the art of the Te-based disk technology with
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Storm water monitoring along loop 202 and Salt River.
DOT National Transportation Integrated Search
2010-10-01
A comprehensive research program for the characterization of storm water runoff from an Arizona : highway was conducted from January through December 2007. The study area covered a portion of : the Loop 202 freeway west of Mesa Drive to a retention b...
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49 CFR 230.111 - Spring rigging.
Code of Federal Regulations, 2010 CFR
2010-10-01
... condition for service. Adjusting weights by shifting weights from one pair of wheels to another is... band; (3) Broken coil springs; or (4) Broken driving box saddle, equalizer, hanger, bolt, or pin...
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Variable-Displacement Hydraulic Drive Unit
NASA Technical Reports Server (NTRS)
Lang, D. J.; Linton, D. J.; Markunas, A.
1986-01-01
Hydraulic power controlled through multiple feedback loops. In hydraulic drive unit, power closely matched to demand, thereby saving energy. Hydraulic flow to and from motor adjusted by motor-control valve connected to wobbler. Wobbler angle determines motor-control-valve position, which in turn determines motor displacement. Concept applicable to machine tools, aircraft controls, and marine controls.
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Regulative Loops, Step Loops and Task Loops
ERIC Educational Resources Information Center
VanLehn, Kurt
2016-01-01
This commentary suggests a generalization of the conception of the behavior of tutoring systems, which the target article characterized as having an outer loop that was executed once per task and an inner loop that was executed once per step of the task. A more general conception sees these two loops as instances of regulative loops, which…
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Circuit for Driving Piezoelectric Transducers
NASA Technical Reports Server (NTRS)
Randall, David P.; Chapsky, Jacob
2009-01-01
The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the
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Gerasimova, N S; Pestov, N A; Kulaeva, O I; Clark, D J; Studitsky, V M
2016-05-26
RNA polymerase II (Pol II) transcription through chromatin is accompanied by formation of small intranucleosomal DNA loops. Pol II captured within a small loop drives accumulation of DNA supercoiling, facilitating further transcription. DNA breaks relieve supercoiling and induce Pol II arrest, allowing detection of DNA damage hidden in chromatin structure.
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Energetics analysis of interstitial loops in single-phase concentrated solid-solution alloys
NASA Astrophysics Data System (ADS)
Wang, Xin-Xin; Niu, Liang-Liang; Wang, Shaoqing
2018-04-01
Systematic energetics analysis on the shape preference, relative stability and radiation-induced segregation of interstitial loops in nickel-containing single-phase concentrated solid-solution alloys have been conducted using atomistic simulations. It is shown that the perfect loops prefer rhombus shape for its low potential energy, while the Frank faulted loops favor ellipse for its low potential energy and the possible large configurational entropy. The decrease of stacking fault energy with increasing compositional complexity provides the energetic driving force for the formation of faulted loops, which, in conjunction with the kinetic factors, explains the experimental observation that the fraction of faulted loops rises with increasing compositional complexity. Notably, the kinetics is primarily responsible for the absence of faulted loops in nickel-cobalt with a very low stacking fault energy. We further demonstrate that the simultaneous nickel enrichment and iron/chromium depletion on interstitial loops can be fully accounted for by their energetics.
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Adaptive Inner-Loop Rover Control
NASA Technical Reports Server (NTRS)
Kulkarni, Nilesh; Ippolito, Corey; Krishnakumar, Kalmanje; Al-Ali, Khalid M.
2006-01-01
Adaptive control technology is developed for the inner-loop speed and steering control of the MAX Rover. MAX, a CMU developed rover, is a compact low-cost 4-wheel drive, 4-wheel steer (double Ackerman), high-clearance agile durable chassis, outfitted with sensors and electronics that make it ideally suited for supporting research relevant to intelligent teleoperation and as a low-cost autonomous robotic test bed and appliance. The design consists of a feedback linearization based controller with a proportional - integral (PI) feedback that is augmented by an online adaptive neural network. The adaptation law has guaranteed stability properties for safe operation. The control design is retrofit in nature so that it fits inside the outer-loop path planning algorithms. Successful hardware implementation of the controller is illustrated for several scenarios consisting of actuator failures and modeling errors in the nominal design.
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Feedback amplification loop drives malignant growth in epithelial tissues.
Muzzopappa, Mariana; Murcia, Lada; Milán, Marco
2017-08-29
Interactions between cells bearing oncogenic mutations and the surrounding microenvironment, and cooperation between clonally distinct cell populations, can contribute to the growth and malignancy of epithelial tumors. The genetic techniques available in Drosophila have contributed to identify important roles of the TNF-α ligand Eiger and mitogenic molecules in mediating these interactions during the early steps of tumor formation. Here we unravel the existence of a tumor-intrinsic-and microenvironment-independent-self-reinforcement mechanism that drives tumor initiation and growth in an Eiger-independent manner. This mechanism relies on cell interactions between two functionally distinct cell populations, and we present evidence that these cell populations are not necessarily genetically different. Tumor-specific and cell-autonomous activation of the tumorigenic JNK stress-activated pathway drives the expression of secreted signaling molecules and growth factors to delaminating cells, which nonautonomously promote proliferative growth of the partially transformed epithelial tissue. We present evidence that cross-feeding interactions between delaminating and nondelaminating cells increase each other's sizes and that these interactions can explain the unlimited growth potential of these tumors. Our results will open avenues toward our molecular understanding of those social cell interactions with a relevant function in tumor initiation in humans.
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Gerasimova, N. S.; Pestov, N. A.; Kulaeva, O. I.; Clark, D. J.; Studitsky, V. M.
2016-01-01
ABSTRACT RNA polymerase II (Pol II) transcription through chromatin is accompanied by formation of small intranucleosomal DNA loops. Pol II captured within a small loop drives accumulation of DNA supercoiling, facilitating further transcription. DNA breaks relieve supercoiling and induce Pol II arrest, allowing detection of DNA damage hidden in chromatin structure. PMID:27115204
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Dynamics and control of instrumented harmonic drives
NASA Technical Reports Server (NTRS)
Kazerooni, H.; Ellis, S. R. (Principal Investigator)
1995-01-01
Since torque in harmonic drives is transmitted by a pure couple, harmonic drives do not generate radial forces and therefore can be instrumented with torque sensors without interference from radial forces. The installation of torque sensors on the stationary component of harmonic drives (the Flexipline cup in this research work) produce backdrivability needed for robotic and telerobotic compliant maneuvers. Backdrivability of a harmonic drive, when used as torque increaser, means that the output shaft can be rotated via finite amount of torque. A high ratio harmonic drive is non-backdrivable because its output shaft cannot be turned by applying a torque on it. This article first develops the dynamic behavior of a harmonic drive, in particular the non-backdrivability, in terms of a sensitivity transfer function. The instrumentation of the harmonic drive with torque sensor is then described. This leads to a description of the control architecture which allows modulation of the sensitivity transfer function within the limits established by the closed-loop stability. A set of experiments on an active hand controller, powered by a DC motor coupled to an instrumented harmonic drive, is given to exhibit this method's limitations.
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Alternating-Current Motor Drive for Electric Vehicles
NASA Technical Reports Server (NTRS)
Krauthamer, S.; Rippel, W. E.
1982-01-01
New electric drive controls speed of a polyphase as motor by varying frequency of inverter output. Closed-loop current-sensing circuit automatically adjusts frequency of voltage-controlled oscillator that controls inverter frequency, to limit starting and accelerating surges. Efficient inverter and ac motor would give electric vehicles extra miles per battery charge.
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Control of adaptive optic element displacement with the help of a magnetic rheology drive
NASA Astrophysics Data System (ADS)
Deulin, Eugeni A.; Mikhailov, Valeri P.; Sytchev, Victor V.
2000-10-01
The control system of adaptive optic of a large astronomical segmentated telescope was designed and tested. The dynamic model and the amplitude-frequency analysis of the new magnetic rheology (MR) drive are presented. The loop controlled drive consists of hydrostatic carrier, MR hydraulic loop controlling system, elastic thin wall seal, stainless seal which are united in a single three coordinate manipulator. This combination ensures short positioning error (delta) (phi)
drive, based on magnetic rheology (MR) liquid are: precision (delta) (phi) loop-controlled MR drive may be expressed: (delta) (phi) equals (delta) r + (delta) db + (delta) f + (delta) i, where (delta) r -- 'reproduction' error (depends on drive structure and controlling system, and in our case the drive ensures (delta) r equals 0); (delta) db -- 'disturbance' error ((delta) db equals 5...10 nm); (delta) f -- error, because of static friction forces action ((delta) f equals kt (DOT) Fst equals 2 (DOT) Is/ki equals 30 nm, where kt -- transformation coefficient of the drive; Fst -- static force in the drive; Is -- 'starting' current in the drive; ki -- transformation coefficient of the measuring system); (delta) i -- 'instrumental' error. In case of a laser interferometer usage (delta) i equals 10 nm and the summarized error is (delta) (phi) drive depends mainly on the combination of time constants of the next elements: MR-valve Tm -
Chromospheric counterparts of solar transition region unresolved fine structure loops
NASA Astrophysics Data System (ADS)
Pereira, Tiago M. D.; Rouppe van der Voort, Luc; Hansteen, Viggo H.; De Pontieu, Bart
2018-04-01
Low-lying loops have been discovered at the solar limb in transition region temperatures by the Interface Region Imaging Spectrograph (IRIS). They do not appear to reach coronal temperatures, and it has been suggested that they are the long-predicted unresolved fine structures (UFS). These loops are dynamic and believed to be visible during both heating and cooling phases. Making use of coordinated observations between IRIS and the Swedish 1-m Solar Telescope, we study how these loops impact the solar chromosphere. We show for the first time that there is indeed a chromospheric signal of these loops, seen mostly in the form of strong Doppler shifts and a conspicuous lack of chromospheric heating. In addition, we find that several instances have a inverse Y-shaped jet just above the loop, suggesting that magnetic reconnection is driving these events. Our observations add several puzzling details to the current knowledge of these newly discovered structures; this new information must be considered in theoretical models. Two movies associated to Fig. 1 are available at http://https://www.aanda.org
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New Technique of AC drive in Tokamak using Permanent Magnets
NASA Astrophysics Data System (ADS)
Matteucci, Jackson; Zolfaghari, Ali
2013-10-01
This study investigates a new technique of capturing the rotational energy of alternating permanent magnets in order to inductively drive an alternating current in tokamak devices. The use of rotational motion bypasses many of the pitfalls seen in typical inductive and non-inductive current drives. Three specific designs are presented and assessed in the following criteria: the profile of the current generated, the RMS loop voltage generated as compared to the RMS power required to maintain it, the system's feasibility from an engineering perspective. All of the analysis has been done under ideal E&M conditions using the Maxwell 3D program. Preliminary results indicate that it is possible to produce an over 99% purely toroidal current with a RMS d Φ/dt of over 150 Tm2/s, driven by 20 MW or less of rotational power. The proposed mechanism demonstrates several key advantages including an efficient mechanical drive system, the generation of pure toroidal currents, and the potential for a quasi-steady state fusion reactor. The following quantities are presented for various driving frequencies and magnet strengths: plasma current generated, loop voltage, torque and power required. This project has been supported by DOE Funding under the SULI program.
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Shi, Yunfei; Yao, Jiang; Young, Jonathan M.; Fee, Judy A.; Perucchio, Renato; Taber, Larry A.
2014-01-01
The morphogenetic process of cardiac looping transforms the straight heart tube into a curved tube that resembles the shape of the future four-chambered heart. Although great progress has been made in identifying the molecular and genetic factors involved in looping, the physical mechanisms that drive this process have remained poorly understood. Recent work, however, has shed new light on this complicated problem. After briefly reviewing the current state of knowledge, we propose a relatively comprehensive hypothesis for the mechanics of the first phase of looping, termed c-looping, as the straight heart tube deforms into a c-shaped tube. According to this hypothesis, differential hypertrophic growth in the myocardium supplies the main forces that cause the heart tube to bend ventrally, while regional growth and cytoskeletal contraction in the omphalomesenteric veins (primitive atria) and compressive loads exerted by the splanchnopleuric membrane drive rightward torsion. A computational model based on realistic embryonic heart geometry is used to test the physical plausibility of this hypothesis. The behavior of the model is in reasonable agreement with available experimental data from control and perturbed embryos, offering support for our hypothesis. The results also suggest, however, that several other mechanisms contribute secondarily to normal looping, and we speculate that these mechanisms play backup roles when looping is perturbed. Finally, some outstanding questions are discussed for future study. PMID:25161623
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Shi, Yunfei; Yao, Jiang; Young, Jonathan M; Fee, Judy A; Perucchio, Renato; Taber, Larry A
2014-01-01
The morphogenetic process of cardiac looping transforms the straight heart tube into a curved tube that resembles the shape of the future four-chambered heart. Although great progress has been made in identifying the molecular and genetic factors involved in looping, the physical mechanisms that drive this process have remained poorly understood. Recent work, however, has shed new light on this complicated problem. After briefly reviewing the current state of knowledge, we propose a relatively comprehensive hypothesis for the mechanics of the first phase of looping, termed c-looping, as the straight heart tube deforms into a c-shaped tube. According to this hypothesis, differential hypertrophic growth in the myocardium supplies the main forces that cause the heart tube to bend ventrally, while regional growth and cytoskeletal contraction in the omphalomesenteric veins (primitive atria) and compressive loads exerted by the splanchnopleuric membrane drive rightward torsion. A computational model based on realistic embryonic heart geometry is used to test the physical plausibility of this hypothesis. The behavior of the model is in reasonable agreement with available experimental data from control and perturbed embryos, offering support for our hypothesis. The results also suggest, however, that several other mechanisms contribute secondarily to normal looping, and we speculate that these mechanisms play backup roles when looping is perturbed. Finally, some outstanding questions are discussed for future study.
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Non-inductive current driven by Alfvén waves in solar coronal loops
NASA Astrophysics Data System (ADS)
Elfimov, A. G.; de Azevedo, C. A.; de Assis, A. S.
1996-08-01
It has been shown that Alfvén waves can drive non-inductive current in solar coronal loops via collisional or collisionless damping. Assuming that all the coronal-loop density of dissipated wave power (W= 10-3 erg cm-3 s-1), which is necessary to keep the plasma hot, is due to Alfvén wave electron heating, we have estimated the axial current density driven by Alfvén waves to be
≈ 103 105 statA cm-2. This current can indeed support the quasi-stationary equilibrium and stability of coronal loops and create the poloidal magnetic field up to B θ≈1-5 G. -
Shielded dual-loop resonator for arterial spin labeling at the neck.
Hetzer, Stefan; Mildner, Toralf; Driesel, Wolfgang; Weder, Manfred; Möller, Harald E
2009-06-01
To construct a dual-loop coil for continuous arterial spin labeling (CASL) at the human neck and characterize it using computer simulations and magnetic resonance experiments. The labeling coil was designed as a perpendicular pair of shielded-loop resonators made from coaxial cable to obtain balanced circular loops with minimal electrical interaction with the lossy tissue. Three different excitation modes depending on the phase shift, Deltapsi, of the currents driving the two circular loops were investigated including a "Maxwell mode" (Deltapsi = 0 degrees ; ie, opposite current directions in both loops), a "quadrature mode" (Deltapsi = 90 degrees ), and a "Helmholtz mode" (Deltapsi = 180 degrees ; ie, identical current directions in both loops). Simulations of the radiofrequency field distribution indicated a high inversion efficiency at the locations of the carotid and vertebral arteries. With a 7-mm-thick polypropylene insulation, a sufficient distance from tissue was achieved to guarantee robust performance at a local specific absorption rate (SAR) well below legal safety limits. Application in healthy volunteers at 3 T yielded quantitative maps of gray matter perfusion with low intersubject variability. The coil permits robust labeling with low SAR and minimal sensitivity to different loading conditions.
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La-CTP: Loop-Aware Routing for Energy-Harvesting Wireless Sensor Networks.
Sun, Guodong; Shang, Xinna; Zuo, Yan
2018-02-02
In emerging energy-harvesting wireless sensor networks (EH-WSN), the sensor nodes can harvest environmental energy to drive their operation, releasing the user's burden in terms of frequent battery replacement, and even enabling perpetual sensing systems. In EH-WSN applications, usually, the node in energy-harvesting or recharging state has to stop working until it completes the energy replenishment. However, such temporary departures of recharging nodes severely impact the packet routing, and one immediate result is the routing loop problem. Controlling loops in connectivity-intermittent EH-WSN in an efficient way is a big challenge in practice, and so far, users still lack of effective and practicable routing protocols with loop handling. Based on the Collection Tree Protocol (CTP) widely used in traditional wireless sensor networks, this paper proposes a loop-aware routing protocol for real-world EH-WSNs, called La-CTP, which involves a new parent updating metric and a proactive, adaptive beaconing scheme to effectively suppress the occurrence of loops and unlock unavoidable loops, respectively. We constructed a 100-node testbed to evaluate La-CTP, and the experimental results showed its efficacy and efficiency.
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La-CTP: Loop-Aware Routing for Energy-Harvesting Wireless Sensor Networks
Sun, Guodong; Shang, Xinna; Zuo, Yan
2018-01-01
In emerging energy-harvesting wireless sensor networks (EH-WSN), the sensor nodes can harvest environmental energy to drive their operation, releasing the user’s burden in terms of frequent battery replacement, and even enabling perpetual sensing systems. In EH-WSN applications, usually, the node in energy-harvesting or recharging state has to stop working until it completes the energy replenishment. However, such temporary departures of recharging nodes severely impact the packet routing, and one immediate result is the routing loop problem. Controlling loops in connectivity-intermittent EH-WSN in an efficient way is a big challenge in practice, and so far, users still lack of effective and practicable routing protocols with loop handling. Based on the Collection Tree Protocol (CTP) widely used in traditional wireless sensor networks, this paper proposes a loop-aware routing protocol for real-world EH-WSNs, called La-CTP, which involves a new parent updating metric and a proactive, adaptive beaconing scheme to effectively suppress the occurrence of loops and unlock unavoidable loops, respectively. We constructed a 100-node testbed to evaluate La-CTP, and the experimental results showed its efficacy and efficiency. PMID:29393876
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New Evidence that Magnetoconvection Drives Solar–Stellar Coronal Heating
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tiwari, Sanjiv K.; Panesar, Navdeep K.; Moore, Ronald L.
2017-07-10
How magnetic energy is injected and released in the solar corona, keeping it heated to several million degrees, remains elusive. Coronal heating generally increases with increasing magnetic field strength. From a comparison of a nonlinear force-free model of the three-dimensional active region coronal field to observed extreme-ultraviolet loops, we find that (1) umbra-to-umbra coronal loops, despite being rooted in the strongest magnetic flux, are invisible, and (2) the brightest loops have one foot in an umbra or penumbra and the other foot in another sunspot’s penumbra or in unipolar or mixed-polarity plage. The invisibility of umbra-to-umbra loops is new evidencemore » that magnetoconvection drives solar-stellar coronal heating: evidently, the strong umbral field at both ends quenches the magnetoconvection and hence the heating. Broadly, our results indicate that depending on the field strength in both feet, the photospheric feet of a coronal loop on any convective star can either engender or quench coronal heating in the loop’s body.« less
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GROWING TRANSVERSE OSCILLATIONS OF A MULTISTRANDED LOOP OBSERVED BY SDO/AIA
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Tongjiang; Ofman, Leon; Su, Yang
The first evidence of transverse oscillations of a multistranded loop with growing amplitudes and internal coupling observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory is presented. The loop oscillation event occurred on 2011 March 8, triggered by a coronal mass ejection (CME). The multiwavelength analysis reveals the presence of multithermal strands in the oscillating loop, whose dynamic behaviors are temperature-dependent, showing differences in their oscillation amplitudes, phases, and emission evolution. The physical parameters of growing oscillations of two strands in 171 A are measured and the three-dimensional loop geometry is determined using STEREO-A/EUVI data. These strandsmore » have very similar frequencies, and between two 193 A strands a quarter-period phase delay sets up. These features suggest the coupling between kink oscillations of neighboring strands and the interpretation by the collective kink mode as predicted by some models. However, the temperature dependence of the multistranded loop oscillations was not studied previously and needs further investigation. The transverse loop oscillations are associated with intensity and loop width variations. We suggest that the amplitude-growing kink oscillations may be a result of continuous non-periodic driving by magnetic deformation of the CME, which deposits energy into the loop system at a rate faster than its loss.« less
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Solid oxide fuel cell power plant with an anode recycle loop turbocharger
Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.
2015-07-14
An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).
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Solid oxide fuel cell power plant with an anode recycle loop turbocharger
Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.
2016-09-27
An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).
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Modeling and Positioning of a PZT Precision Drive System.
Liu, Che; Guo, Yanling
2017-11-08
The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD) is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK) was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied.
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Modeling and Positioning of a PZT Precision Drive System
Liu, Che; Guo, Yanling
2017-01-01
The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD) is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK) was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied. PMID:29117140
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Gunawardhana, Kushan L; Hardin, Paul E
2017-11-20
In Drosophila, the circadian clock is comprised of transcriptional feedback loops that control rhythmic gene expression responsible for daily rhythms in physiology, metabolism, and behavior. The core feedback loop, which employs CLOCK-CYCLE (CLK-CYC) activators and PERIOD-TIMELESS (PER-TIM) repressors to drive rhythmic transcription peaking at dusk, is required for circadian timekeeping and overt behavioral rhythms. CLK-CYC also activates an interlocked feedback loop, which uses the PAR DOMAIN PROTEIN 1ε (PDP1ε) activator and the VRILLE (VRI) repressor to drive rhythmic transcription peaking at dawn. Although Pdp1ε mutants disrupt activity rhythms without eliminating clock function, whether vri is required for clock function and/or output is not known. Using a conditionally inactivatable transgene to rescue vri developmental lethality, we show that clock function persists after vri inactivation but that activity rhythms are abolished. The inactivation of vri disrupts multiple output pathways thought to be important for activity rhythms, including PDF accumulation and arborization rhythms in the small ventrolateral neuron (sLN v ) dorsal projection. These results demonstrate that vri acts as a key regulator of clock output and suggest that the primary function of the interlocked feedback loop in Drosophila is to drive rhythmic transcription required for overt rhythms. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Interplanetary travel: Is gravity needed to close the loop
NASA Technical Reports Server (NTRS)
Vernikos-Danellis, Joan
1988-01-01
Evidence has been accumulating from spaceflight and ground simulation studies suggesting that the normal relationship between neuroendocrine driving mechanisms and their respective target organs may become uncoupled; and that the sensitivity of the various components of the closed-loop systems may be altered. Changes in the regulation of the pituitary-adrenal system and the angioten-sinaldosterone system is discussed in support of this thesis.
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Nagamori, Akira; Laine, Christopher M; Valero-Cuevas, Francisco J
2018-01-01
Involuntary force variability below 15 Hz arises from, and is influenced by, many factors including descending neural drive, proprioceptive feedback, and mechanical properties of muscles and tendons. However, their potential interactions that give rise to the well-structured spectrum of involuntary force variability are not well understood due to a lack of experimental techniques. Here, we investigated the generation, modulation, and interactions among different sources of force variability using a physiologically-grounded closed-loop simulation of an afferented muscle model. The closed-loop simulation included a musculotendon model, muscle spindle, Golgi tendon organ (GTO), and a tracking controller which enabled target-guided force tracking. We demonstrate that closed-loop control of an afferented musculotendon suffices to replicate and explain surprisingly many cardinal features of involuntary force variability. Specifically, we present 1) a potential origin of low-frequency force variability associated with co-modulation of motor unit firing rates (i.e.,'common drive'), 2) an in-depth characterization of how proprioceptive feedback pathways suffice to generate 5-12 Hz physiological tremor, and 3) evidence that modulation of those feedback pathways (i.e., presynaptic inhibition of Ia and Ib afferents, and spindle sensitivity via fusimotor drive) influence the full spectrum of force variability. These results highlight the previously underestimated importance of closed-loop neuromechanical interactions in explaining involuntary force variability during voluntary 'isometric' force control. Furthermore, these results provide the basis for a unifying theory that relates spinal circuitry to various manifestations of altered involuntary force variability in fatigue, aging and neurological disease.
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Steed, P Ryan; Kraft, Kaitlin A; Fillingame, Robert H
2014-11-25
H(+)-transporting F1F0 ATP synthase catalyzes the synthesis of ATP via coupled rotary motors within F0 and F1. H(+) transport at the subunit a-c interface in transmembranous F0 drives rotation of a cylindrical c10 oligomer within the membrane, which is coupled to rotation of subunit γ within the α3β3 sector of F1 to mechanically drive ATP synthesis. F1F0 functions in a reversible manner, with ATP hydrolysis driving H(+) transport. ATP-driven H(+) transport in a select group of cysteine mutants in subunits a and c is inhibited after chelation of Ag(+) and/or Cd(+2) with the substituted sulfhydryl groups. The H(+) transport pathway mapped via these Ag(+)(Cd(+2))-sensitive Cys extends from the transmembrane helices (TMHs) of subunits a and c into cytoplasmic loops connecting the TMHs, suggesting these loop regions could be involved in gating H(+) release to the cytoplasm. Here, using select loop-region Cys from the single cytoplasmic loop of subunit c and multiple cytoplasmic loops of subunit a, we show that Cd(+2) directly inhibits passive H(+) transport mediated by F0 reconstituted in liposomes. Further, in extensions of previous studies, we show that the regions mediating passive H(+) transport can be cross-linked to each other. We conclude that the loop-regions in subunits a and c that are implicated in H(+) transport likely interact in a single structural domain, which then functions in gating H(+) release to the cytoplasm.
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Cutting a Drop of Water Pinned by Wire Loops Using a Superhydrophobic Surface and Knife
Yanashima, Ryan; García, Antonio A.; Aldridge, James; Weiss, Noah; Hayes, Mark A.; Andrews, James H.
2012-01-01
A water drop on a superhydrophobic surface that is pinned by wire loops can be reproducibly cut without formation of satellite droplets. Drops placed on low-density polyethylene surfaces and Teflon-coated glass slides were cut with superhydrophobic knives of low-density polyethylene and treated copper or zinc sheets, respectively. Distortion of drop shape by the superhydrophobic knife enables a clean break. The driving force for droplet formation arises from the lower surface free energy for two separate drops, and it is modeled as a 2-D system. An estimate of the free energy change serves to guide when droplets will form based on the variation of drop volume, loop spacing and knife depth. Combining the cutting process with an electrofocusing driving force could enable a reproducible biomolecular separation without troubling satellite drop formation. PMID:23029297
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Transistorized PWM inverter-induction motor drive system
NASA Technical Reports Server (NTRS)
Peak, S. C.; Plunkett, A. B.
1982-01-01
This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.
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Kerr hysteresis loop tracer with alternate driving magnetic field up to 10 kHz
NASA Astrophysics Data System (ADS)
Callegaro, Luca; Fiorini, Carlo; Triggiani, Giacomo; Puppin, Ezio
1997-07-01
A magneto-optical Kerr loop tracer for hysteresis loop measurements in thin films with field excitation frequency f0 from 10 mHz to 10 kHz is described. A very high sensitivity is obtained by using an ultrabright light-emitting diode as a low-noise light source and a novel acquisition process. The field is generated with a coil driven by an audio amplifier connected to a free-running oscillator. The conditioned detector output constitutes the magnetization signal (M); the magnetic field (H) is measured with a fast Hall probe. The acquisition electronics are based on a set of sample-and-hold amplifiers which allow the simultaneous sampling of M, H, and dH/dt. Acquisition is driven by a personal computer equipped with a multifunction I/O board. Test results on a 120 nm Fe film on Si substrate are shown. The coercive field of the film increases with frequency and nearly doubles at 10 kHz with respect to dc.
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Non-supersymmetric Wilson loop in N = 4 SYM and defect 1d CFT
NASA Astrophysics Data System (ADS)
Beccaria, Matteo; Giombi, Simone; Tseytlin, Arkady A.
2018-03-01
Following Polchinski and Sully (arXiv:1104.5077), we consider a generalized Wilson loop operator containing a constant parameter ζ in front of the scalar coupling term, so that ζ = 0 corresponds to the standard Wilson loop, while ζ = 1 to the locally supersymmetric one. We compute the expectation value of this operator for circular loop as a function of ζ to second order in the planar weak coupling expansion in N = 4 SYM theory. We then explain the relation of the expansion near the two conformal points ζ = 0 and ζ = 1 to the correlators of scalar operators inserted on the loop. We also discuss the AdS5 × S 5 string 1-loop correction to the strong-coupling expansion of the standard circular Wilson loop, as well as its generalization to the case of mixed boundary conditions on the five-sphere coordinates, corresponding to general ζ. From the point of view of the defect CFT1 defined on the Wilson line, the ζ-dependent term can be seen as a perturbation driving a RG flow from the standard Wilson loop in the UV to the supersymmetric Wilson loop in the IR. Both at weak and strong coupling we find that the logarithm of the expectation value of the standard Wilson loop for the circular contour is larger than that of the supersymmetric one, which appears to be in agreement with the 1d analog of the F-theorem.
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NASA Technical Reports Server (NTRS)
Choi, Benjamin B.; Brown, Gerald V.
2017-01-01
It is essential to design a propulsion powertrain real-time simulator using the hardware-in-the-loop (HIL) system that emulates an electrified aircraft propulsion (EAP) systems power grid. This simulator would enable us to facilitate in-depth understanding of the system principles, to validate system model analysis and performance prediction, and to demonstrate the proof-of-concept of the EAP electrical system. This paper describes how subscale electrical machines with their controllers can mimic the power components in an EAP powertrain. In particular, three powertrain emulations are presented to mimic 1) a gas turbo-=shaft engine driving a generator, consisting of two permanent magnet (PM) motors with brushless motor drives, coupled by a shaft, 2) a motor driving a propulsive fan, and 3) a turbo-shaft engine driven fan (turbofan engine) operation. As a first step towards the demonstration, experimental dynamic characterization of the two motor drive systems, coupled by a mechanical shaft, were performed. The previously developed analytical motor models1 were then replaced with the experimental motor models to perform the real-time demonstration in the predefined flight path profiles. This technique can convert the plain motor system into a unique EAP power grid emulator that enables rapid analysis and real-time simulation performance using hardware-in-the-loop (HIL).
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Wei, Zhao; Guo, Haiyang; Liu, Zhaojian; Zhang, Xiyu; Liu, Qiao; Qian, Yanyan; Gong, Yaoqin; Shao, Changshun
2015-02-01
Tumor suppressor p53 is known to regulate the level of intracellular reactive oxygen species (ROS). It can either alleviate oxidative stress under physiological and mildly stressed conditions or exacerbate oxidative stress under highly stressed conditions. We here report that a p53-ROS positive feedback loop drives a senescence program in normal human fibroblasts (NHFs) and this senescence-driving loop is negatively regulated by CUL4B. CUL4B, which can assemble various ubiquitin E3 ligases, was found to be downregulated in stress-induced senescent cells, but not in replicative senescent cells. We observed that p53-dependent ROS production was significantly augmented and stress-induced senescence was greatly enhanced when CUL4B was absent or depleted. Ectopic expression of CUL4B, on the other hand, blunted p53 activation, reduced ROS production, and attenuated cellular senescence in cells treated with H2O2. CUL4B was shown to promote p53 ubiquitination and proteosomal degradation in NHFs exposed to oxidative stress, thus dampening the p53-dependent cellular senescence. Together, our results established a critical role of CUL4B in negatively regulating the p53-ROS positive feedback loop that drives cellular senescence. Copyright © 2014 Elsevier Inc. All rights reserved.
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ERIC Educational Resources Information Center
Jefimenko, Oleg
1974-01-01
Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)
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Extrusion without a motor: a new take on the loop extrusion model of genome organization
Johnson, J.; Michieletto, D.; Morozov, A. N.; Nicodemi, M.; Cook, P. R.; Marenduzzo, D.
2018-01-01
ABSTRACT Chromatin loop extrusion is a popular model for the formation of CTCF loops and topological domains. Recent HiC data have revealed a strong bias in favour of a particular arrangement of the CTCF binding motifs that stabilize loops, and extrusion is the only model to date which can explain this. However, the model requires a motor to generate the loops, and although cohesin is a strong candidate for the extruding factor, a suitable motor protein (or a motor activity in cohesin itself) has yet to be found. Here we explore a new hypothesis: that there is no motor, and thermal motion within the nucleus drives extrusion. Using theoretical modelling and computer simulations we ask whether such diffusive extrusion could feasibly generate loops. Our simulations uncover an interesting ratchet effect (where an osmotic pressure promotes loop growth), and suggest, by comparison to recent in vitro and in vivo measurements, that diffusive extrusion can in principle generate loops of the size observed in the data. Extra View on : C. A. Brackley, J. Johnson, D. Michieletto, A. N. Morozov, M. Nicodemi, P. R. Cook, and D. Marenduzzo “Non-equilibrium chromosome looping via molecular slip-links”, Physical Review Letters 119 138101 (2017) PMID:29300120
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Gregory, Murray R.
2009-01-01
Over the past five or six decades, contamination and pollution of the world’s enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials (generally known as ‘marine debris’) has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as ‘hangers-on and hitch-hikers’ as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats. PMID:19528053
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Gregory, Murray R
2009-07-27
Over the past five or six decades, contamination and pollution of the world's enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials (generally known as 'marine debris') has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as 'hangers-on and hitch-hikers' as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats.
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The Structure, Design, and Closed-Loop Motion Control of a Differential Drive Soft Robot.
Wu, Pang; Jiangbei, Wang; Yanqiong, Fei
2018-02-01
This article presents the structure, design, and motion control of an inchworm inspired pneumatic soft robot, which can perform differential movement. This robot mainly consists of two columns of pneumatic multi-airbags (actuators), one sensor, one baseboard, front feet, and rear feet. According to the different inflation time of left and right actuators, the robot can perform both linear and turning movements. The actuators of this robot are composed of multiple airbags, and the design of the airbags is analyzed. To deal with the nonlinear performance of the soft robot, we use radial basis function neural networks to train the turning ability of this robot on three different surfaces and create a mathematical model among coefficient of friction, deflection angle, and inflation time. Then, we establish the closed-loop automatic control model using three-axis electronic compass sensor. Finally, the automatic control model is verified by linear and turning movement experiments. According to the experiment, the robot can finish the linear and turning movements under the closed-loop control system.
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Study of Fluid Cooling Loop System in Chinese Manned Spacecraft
NASA Astrophysics Data System (ADS)
Jiang, Jun; Xu, Jiwan; Fan, Hanlin; Huang, Jiarong
2002-01-01
change. To solve the questions, a fluid cooling loop system must be applied to Chinese manned spacecraft besides other conventional thermal control methods, such as thermal control coatings, multiplayer insulation blankets, heat pipes, electro-heating adjustment temperature devices, and so on. The paper will introduce the thermal design of inner and outer fluid loop including their constitution and fundamental, etc. The capability of heat transportation and the accuracy of control temperature for the fluid loop will be evaluated and analyzed. To insure the air temperature of sealed cabins within 21+/-4, the inlet liquid temperature of condensing heat exchanger needs to be controlled within 9+/-2. To insure this, the inlet liquid temperature of middle heat exchanger needs to be controlled within 8+/-1.8. The inlet temperature point is controlled by a subsidiary loop adjusting: when the computer receives feedbacks of the deviation and the variety rate of deviation from the controlled temperature point. It drives the temperature control valve to adjust the flow flux distribution between the main loop through radiator and the subsidiary loop which isn't through radiator to control the temperature of the mixed fluid within 8+/-1.8. The paper will also introduce thermal designs of key parts in the cooling loop, such as space radiators, heat exchangers and cooling plates. Thermal simulated tests on the ground and flight tests have been performed to verify correctness of thermal designs. rational and the loop system works order. It realizes the circulation of absorbing heat dissipation to the loop and transferring it to radiator then radiating it to space. (2) loop control system controls inlet temperature of middle heat exchanger within 8+/-1.8 under various thermal cases. Thermal design of the middle heat exchanger insures inlet temperature of condensing heat within 9+/-2. Thereby, the air temperature of sealed cabins is controlled within about 21+/-4 accurately. (3) The
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Seeburger, Joerg; Noack, Thilo; Winkfein, Michael; Ender, Joerg; Mohr, Friedrich Wilhelm
2010-01-01
The loop technique facilitates mitral valve repair for leaflet prolapse by implantation of Gore-Tex neo-chordae. The key feature of the technique is a premade bundle of four loops made out of one suture. The loops are available in different lengths ranging from 10 to 26 mm. After assessment of the ideal length of neo-chordae with a caliper the loops are then secured to the body of the papillary muscle over an additional felt pledget. In the following step, the free ends of the loops are distributed along the free margin of the prolapsing segment using one additional suture for each loop.
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Slow Magnetosonic Waves and Fast Flows in Active Region Loops
NASA Technical Reports Server (NTRS)
Ofman, L.; Wang, T. J.; Davila, J. M.
2012-01-01
Recent extreme ultraviolet spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast (approx 100-300 km/s) quasiperiodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow-driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux tubes and the establishment of siphon flow.We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast-mode waves. The phase speed of the slow magnetosonic waves is close to the coronal sound speed. When the amplitude of the driving pulses is increased we find that slow shock-like wave trains are produced. When the upflows are driven periodically, undamped oscillations are produced with periods determined by the periodicity of the upflows. Based on the results of the 3D MHD model we suggest that the observed slow magnetosonic waves and persistent upflows may be produced by the same impulsive events at the bases of ARs.
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Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola
2016-01-01
Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique. PMID:27426442
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Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola
2016-07-18
Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique.
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NASA Astrophysics Data System (ADS)
Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola
2016-07-01
Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique.
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Lower hybrid current drive experiments in the HT-6M tokamak
NASA Astrophysics Data System (ADS)
Jiang, Tongwen; Liu, Yuexiu; Guo, Wenkang; Zhang, Xuelei; Luo, Jiarong
1987-07-01
Lower hybrid current drive (LHCD) experiments with a multijunction grill have been performed in the HT-6M tokamak. When the RF power pulse with 15ms risetime is injected into the plasma, the toroidal current amplitude is raised, but the temporal variation of the loop voltage does not have measurable change. The efficiency of current drive is Irf/Prf=0.57kA/kW at bar ne=3 × 1012cm-3 and Bt=8KG. It seems that the multijunction grill has the same efficiency as the ordinary grill on the LHCD experiments.
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PLZT Ceramic Driving Rotary Micro-mirror Based on Photoelectric-electrostatic Mechanism
NASA Astrophysics Data System (ADS)
Tang, Yujuan; Yang, Zhong; Chen, Yusong; Wang, Xinjie
2017-12-01
Based on the anomalous photovoltaic effect of PLZT, a rotary micro-mirror driven by hybrid photoelectric-electrostatic actuation of PLZT ceramic is proposed. Firstly, the mathematical modelling of coupled multi-physics fields of PLZT ceramic is established during illumination and light off phases. Then, the relationship between the rotation angle and the photovoltage of PLZT ceramics is established. In addition, the feasibility of rotary micro-mirror with hybrid photoelectric-electrostatic driving is verified via closed-loop control for photo-induced voltage of PLZT ceramic. The experimental results show that the photo-induced voltage of PLZT ceramics has good dynamic control precision using on-off closed-loop control method.
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Short and long sympathetic-sensory feedback loops in white fat
Ryu, Vitaly
2014-01-01
We previously demonstrated white adipose tissue (WAT) innervation using the established WAT retrograde sympathetic nervous system (SNS)-specific transneuronal viral tract tracer pseudorabies virus (PRV152) and showed its role in the control of lipolysis. Conversely, we demonstrated WAT sensory innervation using the established anterograde sensory system (SS)-specific transneuronal viral tracer, the H129 strain of herpes simplex virus-1, with sensory nerves showing responsiveness with increases in WAT SNS drive. Several brain areas were part of the SNS outflow to and SS inflow from WAT between these studies suggesting SNS-SS feedback loops. Therefore, we injected both PRV152 and H129 into inguinal WAT (IWAT) of Siberian hamsters. Animals were perfused on days 5 and 6 postinoculation after H129 and PRV152 injections, respectively, and brains, spinal cords, sympathetic, and dorsal root ganglia (DRG) were processed for immunohistochemical detection of each virus across the neuroaxis. The presence of H129+PRV152-colocalized neurons (∼50%) in the spinal segments innervating IWAT suggested short SNS-SS loops with significant coinfections (>60%) in discrete brain regions, signifying long SNS-SS loops. Notably, the most highly populated sites with the double-infected neurons were the medial part of medial preoptic nucleus, medial preoptic area, hypothalamic paraventricular nucleus, lateral hypothalamus, periaqueductal gray, oral part of the pontine reticular nucleus, and the nucleus of the solitary tract. Collectively, these results strongly indicate the neuroanatomical reality of the central SNS-SS feedback loops with short loops in the spinal cord and long loops in the brain, both likely involved in the control of lipolysis or other WAT pad-specific functions. PMID:24717676
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Le Garrec, Jean-François; Ivanovitch, Kenzo D; Raphaël, Etienne; Bangham, J Andrew; Torres, Miguel; Coen, Enrico; Mohun, Timothy J
2017-01-01
How left-right patterning drives asymmetric morphogenesis is unclear. Here, we have quantified shape changes during mouse heart looping, from 3D reconstructions by HREM. In combination with cell labelling and computer simulations, we propose a novel model of heart looping. Buckling, when the cardiac tube grows between fixed poles, is modulated by the progressive breakdown of the dorsal mesocardium. We have identified sequential left-right asymmetries at the poles, which bias the buckling in opposite directions, thus leading to a helical shape. Our predictive model is useful to explore the parameter space generating shape variations. The role of the dorsal mesocardium was validated in Shh-/- mutants, which recapitulate heart shape changes expected from a persistent dorsal mesocardium. Our computer and quantitative tools provide novel insight into the mechanism of heart looping and the contribution of different factors, beyond the simple description of looping direction. This is relevant to congenital heart defects. PMID:29179813
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Renormalization of loop functions for all loops
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brandt, R.A.; Neri, F.; Sato, M.
1981-08-15
It is shown that the vacuum expectation values W(C/sub 1/,xxx, C/sub n/) of products of the traces of the path-ordered phase factors P exp(igcontour-integral/sub C/iA/sub ..mu../(x)dx/sup ..mu../) are multiplicatively renormalizable in all orders of perturbation theory. Here A/sub ..mu../(x) are the vector gauge field matrices in the non-Abelian gauge theory with gauge group U(N) or SU(N), and C/sub i/ are loops (closed paths). When the loops are smooth (i.e., differentiable) and simple (i.e., non-self-intersecting), it has been shown that the generally divergent loop functions W become finite functions W when expressed in terms of the renormalized coupling constant and multipliedmore » by the factors e/sup -K/L(C/sub i/), where K is linearly divergent and L(C/sub i/) is the length of C/sub i/. It is proved here that the loop functions remain multiplicatively renormalizable even if the curves have any finite number of cusps (points of nondifferentiability) or cross points (points of self-intersection). If C/sub ..gamma../ is a loop which is smooth and simple except for a single cusp of angle ..gamma.., then W/sub R/(C/sub ..gamma../) = Z(..gamma..)W(C/sub ..gamma../) is finite for a suitable renormalization factor Z(..gamma..) which depends on ..gamma.. but on no other characteristic of C/sub ..gamma../. This statement is made precise by introducing a regularization, or via a loop-integrand subtraction scheme specified by a normalization condition W/sub R/(C-bar/sub ..gamma../) = 1 for an arbitrary but fixed loop C-bar/sub ..gamma../. Next, if C/sub ..beta../ is a loop which is smooth and simple except for a cross point of angles ..beta.., then W(C/sub ..beta../) must be renormalized together with the loop functions of associated sets S/sup i//sub ..beta../ = )C/sup i//sub 1/,xxx, C/sup i//sub p/i) (i = 2,xxx,I) of loops C/sup i//sub q/ which coincide with certain parts of C/sub ..beta../equivalentC/sup 1//sub 1/. Then W/sub R/(S/sup i//sub ..beta../) = Z/sup i
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Integral Sensor Fault Detection and Isolation for Railway Traction Drive.
Garramiola, Fernando; Del Olmo, Jon; Poza, Javier; Madina, Patxi; Almandoz, Gaizka
2018-05-13
Due to the increasing importance of reliability and availability of electric traction drives in Railway applications, early detection of faults has become an important key for Railway traction drive manufacturers. Sensor faults are important sources of failures. Among the different fault diagnosis approaches, in this article an integral diagnosis strategy for sensors in traction drives is presented. Such strategy is composed of an observer-based approach for direct current (DC)-link voltage and catenary current sensors, a frequency analysis approach for motor current phase sensors and a hardware redundancy solution for speed sensors. None of them requires any hardware change requirement in the actual traction drive. All the fault detection and isolation approaches have been validated in a Hardware-in-the-loop platform comprising a Real Time Simulator and a commercial Traction Control Unit for a tram. In comparison to safety-critical systems in Aerospace applications, Railway applications do not need instantaneous detection, and the diagnosis is validated in a short time period for reliable decision. Combining the different approaches and existing hardware redundancy, an integral fault diagnosis solution is provided, to detect and isolate faults in all the sensors installed in the traction drive.
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Integral Sensor Fault Detection and Isolation for Railway Traction Drive
del Olmo, Jon; Poza, Javier; Madina, Patxi; Almandoz, Gaizka
2018-01-01
Due to the increasing importance of reliability and availability of electric traction drives in Railway applications, early detection of faults has become an important key for Railway traction drive manufacturers. Sensor faults are important sources of failures. Among the different fault diagnosis approaches, in this article an integral diagnosis strategy for sensors in traction drives is presented. Such strategy is composed of an observer-based approach for direct current (DC)-link voltage and catenary current sensors, a frequency analysis approach for motor current phase sensors and a hardware redundancy solution for speed sensors. None of them requires any hardware change requirement in the actual traction drive. All the fault detection and isolation approaches have been validated in a Hardware-in-the-loop platform comprising a Real Time Simulator and a commercial Traction Control Unit for a tram. In comparison to safety-critical systems in Aerospace applications, Railway applications do not need instantaneous detection, and the diagnosis is validated in a short time period for reliable decision. Combining the different approaches and existing hardware redundancy, an integral fault diagnosis solution is provided, to detect and isolate faults in all the sensors installed in the traction drive. PMID:29757251
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Analysis and design of a 3rd order velocity-controlled closed-loop for MEMS vibratory gyroscopes.
Wu, Huan-ming; Yang, Hai-gang; Yin, Tao; Jiao, Ji-wei
2013-09-18
The time-average method currently available is limited to analyzing the specific performance of the automatic gain control-proportional and integral (AGC-PI) based velocity-controlled closed-loop in a micro-electro-mechanical systems (MEMS) vibratory gyroscope, since it is hard to solve nonlinear functions in the time domain when the control loop reaches to 3rd order. In this paper, we propose a linearization design approach to overcome this limitation by establishing a 3rd order linear model of the control loop and transferring the analysis to the frequency domain. Order reduction is applied on the built linear model's transfer function by constructing a zero-pole doublet, and therefore mathematical expression of each control loop's performance specification is obtained. Then an optimization methodology is summarized, which reveals that a robust, stable and swift control loop can be achieved by carefully selecting the system parameters following a priority order. Closed-loop drive circuits are designed and implemented using 0.35 μm complementary metal oxide semiconductor (CMOS) process, and experiments carried out on a gyroscope prototype verify the optimization methodology that an optimized stability of the control loop can be achieved by constructing the zero-pole doublet, and disturbance rejection capability (D.R.C) of the control loop can be improved by increasing the integral term.
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OncomiR Addiction Is Generated by a miR-155 Feedback Loop in Theileria-Transformed Leukocytes
Medjkane, Souhila; Perichon, Martine; Yin, Qinyan; Flemington, Erik; Weitzman, Matthew D.; Weitzman, Jonathan B.
2013-01-01
The intracellular parasite Theileria is the only eukaryote known to transform its mammalian host cells. We investigated the host mechanisms involved in parasite-induced transformation phenotypes. Tumour progression is a multistep process, yet ‘oncogene addiction’ implies that cancer cell growth and survival can be impaired by inactivating a single gene, offering a rationale for targeted molecular therapies. Furthermore, feedback loops often act as key regulatory hubs in tumorigenesis. We searched for microRNAs involved in addiction to regulatory loops in leukocytes infected with Theileria parasites. We show that Theileria transformation involves induction of the host bovine oncomiR miR-155, via the c-Jun transcription factor and AP-1 activity. We identified a novel miR-155 target, DET1, an evolutionarily-conserved factor involved in c-Jun ubiquitination. We show that miR-155 expression led to repression of DET1 protein, causing stabilization of c-Jun and driving the promoter activity of the BIC transcript containing miR-155. This positive feedback loop is critical to maintain the growth and survival of Theileria-infected leukocytes; transformation is reversed by inhibiting AP-1 activity or miR-155 expression. This is the first demonstration that Theileria parasites induce the expression of host non-coding RNAs and highlights the importance of a novel feedback loop in maintaining the proliferative phenotypes induced upon parasite infection. Hence, parasite infection drives epigenetic rewiring of the regulatory circuitry of host leukocytes, placing miR-155 at the crossroads between infection, regulatory circuits and transformation. PMID:23637592
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Two-loop hard-thermal-loop thermodynamics with quarks
NASA Astrophysics Data System (ADS)
Andersen, Jens O.; Petitgirard, Emmanuel; Strickland, Michael
2004-08-01
We calculate the quark contribution to the free energy of a hot quark-gluon plasma to two-loop order using hard-thermal-loop (HTL) perturbation theory. All ultraviolet divergences can be absorbed into renormalizations of the vacuum energy and the HTL quark and gluon mass parameters. The quark and gluon HTL mass parameters are determined self-consistently by a variational prescription. Combining the quark contribution with the two-loop HTL perturbation theory free energy for pure glue we obtain the total two-loop QCD free energy. Comparisons are made with lattice estimates of the free energy for Nf=2 and with exact numerical results obtained in the large-Nf limit.
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EUV Waves Driven by the Sudden Expansion of Transequatorial Loops Caused by Coronal Jets
NASA Astrophysics Data System (ADS)
Shen, Yuandeng; Tang, Zehao; Miao, Yuhu; Su, Jiangtao; Liu, Yu
2018-06-01
We present two events to study the driving mechanism of extreme-ultraviolet (EUV) waves that are not associated with coronal mass ejections (CMEs), by using high-resolution observations taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Observational results indicate that the observed EUV waves were accompanied by flares and coronal jets, but not the CMEs that were regarded as drivers of most EUV waves in previous studies. In the first case, it is observed that a coronal jet is ejected along a transequatorial loop system at a plane-of-the-sky (POS) speed of 335 ± 22 km s{}-1; in the meantime, an arc-shaped EUV wave appeared on the eastern side of the loop system. In addition, the EUV wave further interacted with another interconnecting loop system and launched a fast propagating (QFP) magnetosonic wave along the loop system, which had a period of 200 s and a speed of 388 ± 65 km s{}-1, respectively. In the second case, we observed a coronal jet that ejected at a POS speed of 282 ± 44 km s{}-1 along a transequatorial loop system as well as the generation of bright EUV waves on the eastern side of the loop system. Based on the observational results, we propose that the observed EUV waves on the eastern side of the transequatorial loop systems are fast-mode magnetosonic waves and that they are driven by the sudden lateral expansion of the transequatorial loop systems due to the direct impingement of the associated coronal jets, while the QFP wave in the fist case formed due to the dispersive evolution of the disturbance caused by the interaction between the EUV wave and the interconnecting coronal loops. It is noted that EUV waves driven by sudden loop expansions have shorter lifetimes than those driven by CMEs.
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Observations of decay-less low-amplitude kink oscillations of EUV coronal loops
NASA Astrophysics Data System (ADS)
Nisticò, Giuseppe; Nakariakov, Valery; Anfinogentov, Sergey
The high spatial and temporal resolution observations at Extreme Ultra-Violet (EUV) wavelengths from the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO) reveal new features in kink oscillations of coronal loops. We show that, in addition to the well-known rapidly decaying oscillations, a new type of kink waves is present, characterized by low-amplitude and undamped oscillations, that we define as decay-less. Typical periods range from 2.5 to 12 min in both regimes and are different for different loops, increasing with the loop length. Estimates of the loop lengths are supported by three dimensional reconstruction of the loop geometry. The amplitude for the decay-less regime is about 1 Mm, close to the spatial resolution of the AIA instruments. The oscillation phase, measured by the cross-correlation method, is found to be constant along each analysed loop, and the spatial structure of the phase of the oscillations corresponds to the fundamental standing kink mode. We show that the observed behaviours are consistent with the empirical model of a damped linear oscillator excited by a continuous low-amplitude harmonic driver, in addition to an eventual impulsive high-amplitude driver. The observed life-time of the oscillations is likely to be determined by the observational conditions rather than any physical damping. However, the balance between the driving and damping is a necessary ingredient of this model. The properties of this type of transverse oscillations make them interesting object of study in the framework of resonant absorption theory and coronal heating process.
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Eglin virtual range database for hardware-in-the-loop testing
NASA Astrophysics Data System (ADS)
Talele, Sunjay E.; Pickard, J. W., Jr.; Owens, Monte A.; Foster, Joseph; Watson, John S.; Amick, Mary Amenda; Anthony, Kenneth
1998-07-01
Realistic backgrounds are necessary to support high fidelity hardware-in-the-loop testing. Advanced avionics and weapon system sensors are driving the requirement for higher resolution imagery. The model-test-model philosophy being promoted by the T&E community is resulting in the need for backgrounds that are realistic or virtual representations of actual test areas. Combined, these requirements led to a major upgrade of the terrain database used for hardware-in-the-loop testing at the Guided Weapons Evaluation Facility (GWEF) at Eglin Air Force Base, Florida. This paper will describe the process used to generate the high-resolution (1-foot) database of ten sites totaling over 20 square kilometers of the Eglin range. this process involved generating digital elevation maps from stereo aerial imagery and classifying ground cover material using the spectral content. These databases were then optimized for real-time operation at 90 Hz.
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Behaviour of fractional loop delay zero crossing digital phase locked loop (FR-ZCDPLL)
NASA Astrophysics Data System (ADS)
Nasir, Qassim
2018-01-01
This article analyses the performance of the first-order zero crossing digital phase locked loops (FR-ZCDPLL) when fractional loop delay is added to loop. The non-linear dynamics of the loop is presented, analysed and examined through bifurcation behaviour. Numerical simulation of the loop is conducted to proof the mathematical analysis of the loop operation. The results of the loop simulation show that the proposed FR-ZCDPLL has enhanced the performance compared to the conventional zero crossing DPLL in terms of wider lock range, captured range and stable operation region. In addition, extensive experimental simulation was conducted to find the optimum loop parameters for different loop environmental conditions. The addition of the fractional loop delay network in the conventional loop also reduces the phase jitter and its variance especially when the signal-to-noise ratio is low.
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Frequencies of Flare Occurrence: Interaction between Convection and Coronal Loops
NASA Astrophysics Data System (ADS)
Mullan, D. J.; Paudel, R. R.
2018-02-01
Observations of solar and stellar flares have revealed the presence of power-law dependences between the flare energy and the time interval between flares. Various models have been proposed to explain these dependences and the numerical value of the power-law indices. Here, we propose a model in which convective flows in granules force the footpoints of coronal magnetic loops, which are frozen-in to photospheric gas, to undergo a random walk. In certain conditions, this can lead to a twist in the loop, which drives the loop unstable if the twist exceeds a critical value. The possibility that a solar flare is caused by such a twist-induced instability in a loop has been in the literature for decades. Here, we quantify the process in an approximate way with a view to replicating the power-law index. We find that, for relatively small flares, the random walk twisting model leads to a rather steep power-law slope that agrees very well with the index derived from a sample of 56,000+ solar X-ray flares reported by the GOES satellites. For relatively large flares, we find that the slope of the power law is shallower. The empirical power-law slopes reported for flare stars also have a range that overlaps with the slopes obtained here. We suggest that in the coolest stars, a significant change in slope should occur when the frozen-flux assumption breaks down due to low electrical conductivity.
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iDriving (Intelligent Driving)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Malikopoulos, Andreas
2012-09-17
iDriving identifies the driving style factors that have a major impact on fuel economy. An optimization framework is used with the aim of optimizing a driving style with respect to these driving factors. A set of polynomial metamodels is constructed to reflect the responses produced in fuel economy by changing the driving factors. The optimization framework is used to develop a real-time feedback system, including visual instructions, to enable drivers to alter their driving styles in responses to actual driving conditions to improve fuel efficiency.
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BMP signaling controls buckling forces to modulate looping morphogenesis of the gut.
Nerurkar, Nandan L; Mahadevan, L; Tabin, Clifford J
2017-02-28
Looping of the initially straight embryonic gut tube is an essential aspect of intestinal morphogenesis, permitting proper placement of the lengthy small intestine within the confines of the body cavity. The formation of intestinal loops is highly stereotyped within a given species and results from differential-growth-driven mechanical buckling of the gut tube as it elongates against the constraint of a thin, elastic membranous tissue, the dorsal mesentery. Although the physics of this process has been studied, the underlying biology has not. Here, we show that BMP signaling plays a critical role in looping morphogenesis of the avian small intestine. We first exploited differences between chicken and zebra finch gut morphology to identify the BMP pathway as a promising candidate to regulate differential growth in the gut. Next, focusing on the developing chick small intestine, we determined that Bmp2 expressed in the dorsal mesentery establishes differential elongation rates between the gut tube and mesentery, thereby regulating the compressive forces that buckle the gut tube into loops. Consequently, the number and tightness of loops in the chick small intestine can be increased or decreased directly by modulation of BMP activity in the small intestine. In addition to providing insight into the molecular mechanisms underlying intestinal development, our findings provide an example of how biochemical signals act on tissue-level mechanics to drive organogenesis, and suggest a possible mechanism by which they can be modulated to achieve distinct morphologies through evolution.
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BMP signaling controls buckling forces to modulate looping morphogenesis of the gut
Nerurkar, Nandan L.; Mahadevan, L.; Tabin, Clifford J.
2017-01-01
Looping of the initially straight embryonic gut tube is an essential aspect of intestinal morphogenesis, permitting proper placement of the lengthy small intestine within the confines of the body cavity. The formation of intestinal loops is highly stereotyped within a given species and results from differential-growth–driven mechanical buckling of the gut tube as it elongates against the constraint of a thin, elastic membranous tissue, the dorsal mesentery. Although the physics of this process has been studied, the underlying biology has not. Here, we show that BMP signaling plays a critical role in looping morphogenesis of the avian small intestine. We first exploited differences between chicken and zebra finch gut morphology to identify the BMP pathway as a promising candidate to regulate differential growth in the gut. Next, focusing on the developing chick small intestine, we determined that Bmp2 expressed in the dorsal mesentery establishes differential elongation rates between the gut tube and mesentery, thereby regulating the compressive forces that buckle the gut tube into loops. Consequently, the number and tightness of loops in the chick small intestine can be increased or decreased directly by modulation of BMP activity in the small intestine. In addition to providing insight into the molecular mechanisms underlying intestinal development, our findings provide an example of how biochemical signals act on tissue-level mechanics to drive organogenesis, and suggest a possible mechanism by which they can be modulated to achieve distinct morphologies through evolution. PMID:28193855
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Laine, Christopher M.; Valero-Cuevas, Francisco J.
2018-01-01
Involuntary force variability below 15 Hz arises from, and is influenced by, many factors including descending neural drive, proprioceptive feedback, and mechanical properties of muscles and tendons. However, their potential interactions that give rise to the well-structured spectrum of involuntary force variability are not well understood due to a lack of experimental techniques. Here, we investigated the generation, modulation, and interactions among different sources of force variability using a physiologically-grounded closed-loop simulation of an afferented muscle model. The closed-loop simulation included a musculotendon model, muscle spindle, Golgi tendon organ (GTO), and a tracking controller which enabled target-guided force tracking. We demonstrate that closed-loop control of an afferented musculotendon suffices to replicate and explain surprisingly many cardinal features of involuntary force variability. Specifically, we present 1) a potential origin of low-frequency force variability associated with co-modulation of motor unit firing rates (i.e.,‘common drive’), 2) an in-depth characterization of how proprioceptive feedback pathways suffice to generate 5-12 Hz physiological tremor, and 3) evidence that modulation of those feedback pathways (i.e., presynaptic inhibition of Ia and Ib afferents, and spindle sensitivity via fusimotor drive) influence the full spectrum of force variability. These results highlight the previously underestimated importance of closed-loop neuromechanical interactions in explaining involuntary force variability during voluntary ‘isometric’ force control. Furthermore, these results provide the basis for a unifying theory that relates spinal circuitry to various manifestations of altered involuntary force variability in fatigue, aging and neurological disease. PMID:29309405
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2016-09-15
A series of active regions stretched along the right side of the sun exhibited a wide variety of loops cascading above them (Sept. 12-14, 2016). The active region near the center has tightly coiled loops, while the region rotating over the right edge has some elongated and some very stretched loops above it. The loops are actually charged particles spiraling along magnetic field lines, observed here in a wavelength of extreme ultraviolet light. Near the middle of the video the Earth quickly passes in front of a portion of the sun as viewed by SDO. http://photojournal.jpl.nasa.gov/catalog/PIA16997
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Closed loop cavitation control - A step towards sonomechatronics.
Saalbach, Kai-Alexander; Ohrdes, Hendrik; Twiefel, Jens
2018-06-01
In the field of sonochemistry, many processes are made possible by the generation of cavitation. This article is about closed loop control of ultrasound assisted processes with the aim of controlling the intensity of cavitation-based sonochemical processes. This is the basis for a new research field which the authors call "sonomechatronics". In order to apply closed loop control, a so called self-sensing technique is applied, which uses the ultrasound transducer's electrical signals to gain information about cavitation activity. Experiments are conducted to find out if this self-sensing technique is capable of determining the state and intensity of acoustic cavitation. A distinct frequency component in the transducer's current signal is found to be a good indicator for the onset and termination of transient cavitation. Measurements show that, depending on the boundary conditions, the onset and termination of transient cavitation occur at different thresholds, with the onset occurring at a higher value in most cases. This known hysteresis effect offers the additional possibility of achieving an energetic optimization by controlling cavitation generation. Using the cavitation indicator for the implementation of a double set point closed loop control, the mean driving current was reduced by approximately 15% compared to the value needed to exceed the transient cavitation threshold. The results presented show a great potential for the field of sonomechatronics. Nevertheless, further investigations are necessary in order to design application-specific sonomechatronic processes. Copyright © 2018 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Li, Yuan; Zhou, Yusheng; Wang, Yong; Ling, Qiang; Chen, Bing; Dou, Yan; Zhang, Wei; Gao, Weiqing; Guo, Zhiqiang; Zhang, Junxiang
2018-03-01
We theoretically study the squeezed probe light passing through a double electromagnetically induced transparency (DEIT) system, in which a microwave field and two coupling lights drive a loop transition. It is shown that the output squeezing can be maintained in both two transparency windows of DEIT, and it can also be manipulated by the relative phase of the three driving fields. The influence of the intensity of applied fields and the optical depth of atoms on the squeezing is also investigated. This study offers possibilities to manipulate the squeezing propagation in atomic media by the phase of electromagnetic fields.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Vukovic, M.; Harper, M.; Breun, R.
1995-12-31
Current drive experiments on the Phaedrus-T tokamak performed with a low field side two-strap fast wave antenna at frequencies below {omega}{sub cH} show loop volt drops of up to 30% with strap phasing (0, {pi}/2). RF induced density fluctuations in the plasma core have also been observed with a microwave reflectometer. It is believed that they are caused by kinetic Alfven waves generated by mode conversion of fast waves at the Alfven resonance. Correlation of the observed density fluctuations with the magnitude of the {Delta}V{sub loop} suggest that the {Delta}V{sub loop} is attributable to current drive/heating due to mode convertedmore » kinetic Alfven waves. The toroidal cold plasma wave code LION is used to model the Alfven resonance mode conversion surfaces in the experiments while the cylindrical hot plasma kinetic wave code ISMENE is used to model the behavior of kinetic Alfven waves at the Alfven resonance location. Initial results obtained from limited density, magnetic field, antenna phase, and impurity scans show good agreement between the RF induced density fluctuations and the predicted behavior of the kinetic Alfven waves. Detailed comparisons between the density fluctuations and the code predictions are presented.« less
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Intelligent Gate Drive for Fast Switching and Crosstalk Suppression of SiC Devices
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhang, Zheyu; Dix, Jeffery; Wang, Fei Fred
This study presents an intelligent gate drive for silicon carbide (SiC) devices to fully utilize their potential of high switching-speed capability in a phase-leg configuration. Based on the SiC device's intrinsic properties, a gate assist circuit consisting of two auxiliary transistors with two diodes is introduced to actively control gate voltages and gate loop impedances of both devices in a phase-leg configuration during different switching transients. Compared to conventional gate drives, the proposed circuit has the capability of accelerating the switching speed of the phase-leg power devices and suppressing the crosstalk to below device limits. Based on Wolfspeed 1200-V SiCmore » MOSFETs, the test results demonstrate the effectiveness of this intelligent gate drive under varying operating conditions. More importantly, the proposed intelligent gate assist circuitry is embedded into a gate drive integrated circuit, offering a simple, compact, and reliable solution for end-users to maximize benefits of SiC devices in actual power electronics applications.« less
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Intelligent Gate Drive for Fast Switching and Crosstalk Suppression of SiC Devices
Zhang, Zheyu; Dix, Jeffery; Wang, Fei Fred; ...
2017-01-19
This study presents an intelligent gate drive for silicon carbide (SiC) devices to fully utilize their potential of high switching-speed capability in a phase-leg configuration. Based on the SiC device's intrinsic properties, a gate assist circuit consisting of two auxiliary transistors with two diodes is introduced to actively control gate voltages and gate loop impedances of both devices in a phase-leg configuration during different switching transients. Compared to conventional gate drives, the proposed circuit has the capability of accelerating the switching speed of the phase-leg power devices and suppressing the crosstalk to below device limits. Based on Wolfspeed 1200-V SiCmore » MOSFETs, the test results demonstrate the effectiveness of this intelligent gate drive under varying operating conditions. More importantly, the proposed intelligent gate assist circuitry is embedded into a gate drive integrated circuit, offering a simple, compact, and reliable solution for end-users to maximize benefits of SiC devices in actual power electronics applications.« less
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Loop-the-Loop: An Easy Experiment, A Challenging Explanation
NASA Astrophysics Data System (ADS)
Asavapibhop, B.; Suwonjandee, N.
2010-07-01
A loop-the-loop built by the Institute for the Promotion of Teaching Science and Technology (IPST) was used in Thai high school teachers training program to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. We took videos using high speed camera to record the motions of a spherical steel ball moving down the aluminum inclined track at different released positions. The ball then moved into the circular loop and underwent a projectile motion upon leaving the track. We then asked the teachers to predict the landing position of the ball if we changed the height of the whole loop-the-loop system. We also analyzed the videos using Tracker, a video analysis software. It turned out that most teachers did not realize the effect of the friction between the ball and the track and could not obtain the correct relationship hence their predictions were inconsistent with the actual landing positions of the ball.
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Loop-the-Loop: Bringing Theory into Practice
ERIC Educational Resources Information Center
Suwonjandee, N.; Asavapibhop, B.
2012-01-01
During the Thai high-school physics teacher training programme, we used an aluminum loop-the-loop system built by the Institute for the Promotion of Teaching Science and Technology (IPST) to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. There were 27 high-school teachers from three provinces,…
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NASA Technical Reports Server (NTRS)
Nishikawa, K.-I.; Sakai, J.-I.; Zhao, Jie; Neubert, T.; Buneman, Oscar
1994-01-01
We have studied the dynamics of a coalescence of current loops using three-dimensional electromagnetic (EM) particle simulation code. Our focus is the investigation of such kinetic processes as energy trasnfer, heating particles, and electromagnetic emissions associated with a current loop coalescence which cannot be studied by MHD simulations. First, the two loops undergo a pinching oscillation due to a pressure imbalance between the inside and outside of the current loop. During the pinching oscillation, a kinetic kink instability is excited and electrons in the loops are heated perpendicularly to an ambient magnetic field. Next, the two current loops collide and coalesce, while at the same time a helical structure grows further. Subsequently, the perturbed current, which is due to these helically bunched electrons, can drive a whistler instability. It should be noted in this case that the whistler wave is excited by the kinetic kink instability and not a beam instability. After the coalescence of two helical loops, tilting motions can be observed in the direction of left-hand rotation, and the helical structure will relax resulting in strong plasma heating mostly in the direction perpendicular to the ambient magnetic field. It is also shown that high-frequency electromagnetic waves can be emitted from the region where the two loops coalesce and propagate strongly in the direction of the electron drift velocity. These processes may be important in understanding heating mechansims for coronal loops as well as radio wave emission mechanisms from active regions of solar plasmas.
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Bio-Inspired Controller on an FPGA Applied to Closed-Loop Diaphragmatic Stimulation
Zbrzeski, Adeline; Bornat, Yannick; Hillen, Brian; Siu, Ricardo; Abbas, James; Jung, Ranu; Renaud, Sylvie
2016-01-01
Cervical spinal cord injury can disrupt connections between the brain respiratory network and the respiratory muscles which can lead to partial or complete loss of ventilatory control and require ventilatory assistance. Unlike current open-loop technology, a closed-loop diaphragmatic pacing system could overcome the drawbacks of manual titration as well as respond to changing ventilation requirements. We present an original bio-inspired assistive technology for real-time ventilation assistance, implemented in a digital configurable Field Programmable Gate Array (FPGA). The bio-inspired controller, which is a spiking neural network (SNN) inspired by the medullary respiratory network, is as robust as a classic controller while having a flexible, low-power and low-cost hardware design. The system was simulated in MATLAB with FPGA-specific constraints and tested with a computational model of rat breathing; the model reproduced experimentally collected respiratory data in eupneic animals. The open-loop version of the bio-inspired controller was implemented on the FPGA. Electrical test bench characterizations confirmed the system functionality. Open and closed-loop paradigm simulations were simulated to test the FPGA system real-time behavior using the rat computational model. The closed-loop system monitors breathing and changes in respiratory demands to drive diaphragmatic stimulation. The simulated results inform future acute animal experiments and constitute the first step toward the development of a neuromorphic, adaptive, compact, low-power, implantable device. The bio-inspired hardware design optimizes the FPGA resource and time costs while harnessing the computational power of spike-based neuromorphic hardware. Its real-time feature makes it suitable for in vivo applications. PMID:27378844
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Sequence-structure relationships in RNA loops: establishing the basis for loop homology modeling.
Schudoma, Christian; May, Patrick; Nikiforova, Viktoria; Walther, Dirk
2010-01-01
The specific function of RNA molecules frequently resides in their seemingly unstructured loop regions. We performed a systematic analysis of RNA loops extracted from experimentally determined three-dimensional structures of RNA molecules. A comprehensive loop-structure data set was created and organized into distinct clusters based on structural and sequence similarity. We detected clear evidence of the hallmark of homology present in the sequence-structure relationships in loops. Loops differing by <25% in sequence identity fold into very similar structures. Thus, our results support the application of homology modeling for RNA loop model building. We established a threshold that may guide the sequence divergence-based selection of template structures for RNA loop homology modeling. Of all possible sequences that are, under the assumption of isosteric relationships, theoretically compatible with actual sequences observed in RNA structures, only a small fraction is contained in the Rfam database of RNA sequences and classes implying that the actual RNA loop space may consist of a limited number of unique loop structures and conserved sequences. The loop-structure data sets are made available via an online database, RLooM. RLooM also offers functionalities for the modeling of RNA loop structures in support of RNA engineering and design efforts.
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LOOP CALCULUS AND BELIEF PROPAGATION FOR Q-ARY ALPHABET: LOOP TOWER
DOE Office of Scientific and Technical Information (OSTI.GOV)
CHERTKOV, MICHAEL; CHERNYAK, VLADIMIR
Loop calculus introduced in [1], [2] constitutes a new theoretical tool that explicitly expresses symbol Maximum-A-Posteriori (MAP) solution of a general statistical inference problem via a solution of the Belief Propagation (BP) equations. This finding brought a new significance to the BP concept, which in the past was thought of as just a loop-free approximation. In this paper they continue a discussion of the Loop Calculus, partitioning the results into three Sections. In Section 1 they introduce a new formulation of the Loop Calculus in terms of a set of transformations (gauges) that keeping the partition function of the problemmore » invariant. The full expression contains two terms referred to as the 'ground state' and 'excited states' contributions. The BP equations are interpreted as a special (BP) gauge fixing condition that emerges as a special orthogonality constraint between the ground state and excited states, which also selects loop contributions as the only surviving ones among the excited states. In Section 2 they demonstrate how the invariant interpretation of the Loop Calculus, introduced in Section 1, allows a natural extension to the case of a general q-ary alphabet, this is achieved via a loop tower sequential construction. The ground level in the tower is exactly equivalent to assigning one color (out of q available) to the 'ground state' and considering all 'excited' states colored in the remaining (q-1) colors, according to the loop calculus rule. Sequentially, the second level in the tower corresponds to selecting a loop from the previous step, colored in (q-1) colors, and repeating the same ground vs excited states splitting procedure into one and (q-2) colors respectively. The construction proceeds till the full (q-1)-levels deep loop tower (and the corresponding contributions to the partition function) are established. In Section 3 they discuss an ultimate relation between the loop calculus and the Bethe-Free energy variational
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Livermore Compiler Analysis Loop Suite
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hornung, R. D.
2013-03-01
LCALS is designed to evaluate compiler optimizations and performance of a variety of loop kernels and loop traversal software constructs. Some of the loop kernels are pulled directly from "Livermore Loops Coded in C", developed at LLNL (see item 11 below for details of earlier code versions). The older suites were used to evaluate floating-point performances of hardware platforms prior to porting larger application codes. The LCALS suite is geared toward assissing C++ compiler optimizations and platform performance related to SIMD vectorization, OpenMP threading, and advanced C++ language features. LCALS contains 20 of 24 loop kernels from the older Livermoremore » Loop suites, plus various others representative of loops found in current production appkication codes at LLNL. The latter loops emphasize more diverse loop constructs and data access patterns than the others, such as multi-dimensional difference stencils. The loops are included in a configurable framework, which allows control of compilation, loop sampling for execution timing, which loops are run and their lengths. It generates timing statistics for analysis and comparing variants of individual loops. Also, it is easy to add loops to the suite as desired.« less
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Neuromorphic meets neuromechanics, part II: the role of fusimotor drive.
Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Joon Sohn, Won; Loeb, Gerald E; Sanger, Terence D; Valero-Cuevas, Francisco J
2017-04-01
We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bi-directional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our Neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function-and its pathologies such as dystonia and spasticity. In
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Ganther, Jr., Kenneth R.; Snapp, Lowell D.
2002-09-10
A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.
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Introduction to Loop Heat Pipes
NASA Technical Reports Server (NTRS)
Ku, Jentung
2015-01-01
This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.
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NASA Astrophysics Data System (ADS)
Sever, Amit; Vieira, Pedro; Wang, Tianheng
2011-11-01
We extend the Operator Product Expansion for Null Polygon Wilson loops to the Mason-Skinner-Caron-Huot super loop dual to non MHV gluon amplitudes. We explain how the known tree level amplitudes can be promoted into an infinite amount of data at any loop order in the OPE picture. As an application, we re-derive all one loop NMHV six gluon amplitudes by promoting their tree level expressions. We also present some new all loops predictions for these amplitudes.
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Looped star polymers show conformational transition from spherical to flat toroidal shapes.
Reiss, Pascal; Fritsche, Miriam; Heermann, Dieter W
2011-11-01
Inspired by the topological organization of the circular Escherichia coli chromosome, which is compacted by separate domains, we study a polymer architecture consisting of a central ring to which either looped or linear side chains are grafted. A shape change from a spherical to a toroidal organization takes place as soon as the inner ring becomes large enough for the attached arms to fit within its circumference. Building up a torus, the system flattens, depending on the effective bending rigidity of the chain induced by entropic repulsion of the attached loops and, to a lesser extent, linear arms. Our results suggest that the natural formation of a toroidal structure with a decreased amount of writhe induced by a specific underlying topology could be one driving force, among others, that nature exploits to ensure proper packaging of the genetic material within a rod-shaped, bacterial envelope.
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Data That Drive: Closing the Loop in the Learning Hospital System
Liu, Vincent X.; Morehouse, John W.; Baker, Jennifer M.; Greene, John D.; Kipnis, Patricia; Escobar, Gabriel J.
2017-01-01
The learning healthcare system describes a vision of US healthcare that capitalizes on science, information technology, incentives, and care culture to drive improvements in the quality of health care. The inpatient setting, one of the most costly and impactful domains of healthcare, is an ideal setting in which to use data and information technology to foster continuous learning and quality improvement. The rapid digitization of inpatient medicine offers incredible new opportunities to use data from routine care to generate new discovery and thus close the virtuous cycle of learning. We use an object lesson—sepsis care within the 21 hospitals of the Kaiser Permanente Northern California integrated healthcare delivery system—to offer insight into the critical elements necessary for developing a learning hospital system. We then describe how a hospital-wide data-driven approach to inpatient care can facilitate improvements in the quality of hospital care. PMID:27805797
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Green, W.L.
1980-12-01
An improved continuous-path-positioning servo-control system is provided for reducing the effects of friction arising at very low cutting speeds in the drive trains of numerically controlled cutting machines, and the like. The improvement comprises a feed forward network for altering the gain of the servo-control loop at low positioning velocities to prevent stick-slip movement of the cutting tool holder being positioned by the control system. The feed forward network shunts conventional lag-compensators in the control loop, or loops, so that the error signal used for positioning varies linearly when the value is small, but being limited for larger values. Thus, at higher positioning speeds there is little effect of the added component upon the control being achieved.
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Banks, Victoria A; Stanton, Neville A
2016-11-01
To the average driver, the concept of automation in driving infers that they can become completely 'hands and feet free'. This is a common misconception, however, one that has been shown through the application of Network Analysis to new Cruise Assist technologies that may feature on our roads by 2020. Through the adoption of a Systems Theoretic approach, this paper introduces the concept of driver-initiated automation which reflects the role of the driver in highly automated driving systems. Using a combination of traditional task analysis and the application of quantitative network metrics, this agent-based modelling paper shows how the role of the driver remains an integral part of the driving system implicating the need for designers to ensure they are provided with the tools necessary to remain actively in-the-loop despite giving increasing opportunities to delegate their control to the automated subsystems. Practitioner Summary: This paper describes and analyses a driver-initiated command and control system of automation using representations afforded by task and social networks to understand how drivers remain actively involved in the task. A network analysis of different driver commands suggests that such a strategy does maintain the driver in the control loop.
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Automatic control of the preload in adaptive friction drives of chemical production machines
NASA Astrophysics Data System (ADS)
Balakin, P. D.
2017-08-01
Being based on the principle of providing the systems with adaptation property to the real parameters and operational condition, the energy effective mechanical system constructed on the base of friction gear with automated preload is offered and this allows keeping mechanical efficiency value adequate transforming drive path to in the terms of multimode operation. This is achieved by integrated control loop, operating on the basis of the laws of motion with the energy of the main power flow by changing automatically the kinematic dimension of the section and, hence, the value of preload in the friction contact. The given ratios of forces and deformations in the control loop are required at the stage of conceptual design to determine design dimensions of power transmission elements with new properties.
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Zhang, Zheng Z.; Pannunzio, Nicholas R.; Han, Li; Hsieh, Chih-Lin; Yu, Kefei; Lieber, Michael R.
2014-01-01
SUMMARY R-loops exist at the murine IgH switch regions and possibly other locations, but their functional importance is unclear. In biochemical systems, R-loop initiation requires DNA sequence regions containing clusters of G nucleotides, but cellular studies have not been done. Here, we vary the G-clustering, total switch region length, and the number of target sites (WGCW sites for the activation-induced deaminase) at synthetic switch regions in a murine B cell line to determine the effect on class switch recombination (CSR). G-clusters increase CSR, regardless of their immediate proximity to the WGCW sites. This increase is accompanied by an increase in R-loop formation. CSR efficiency correlates better with the absolute number of WGCW sites in the switch region rather than the total switch region length or density of WGCW sites. Thus, the overall strength of the switch region depends on G-clusters, which initiate R-loop formation, and on the number of WGCW sites. PMID:25017067
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NASA Astrophysics Data System (ADS)
Liu, Sen; Gang, Tieqiang
2018-03-01
Harmonic drives are widely used in aerospace and industrial robots. Flexibility, friction and parameter uncertainty will result in transmission performance degradation. In this paper, an adaptive back-stepping method with friction compensation is proposed to improve the tracking performance of the harmonic drive system. The nonlinear friction is described by LuGre model and compensated with a friction observer, and the uncertainty of model parameters is resolved by adaptive parameter estimation method. By using Lyapunov stability theory, it is proved that all the errors of the closed-loop system are uniformly ultimately bounded. Simulations illustrate the effectiveness of our friction compensation method.
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Abe-Yoshizumi, Rei; Kobayashi, Shiori; Gohara, Mizuki; Hayashi, Kokoro; Kojima, Chojiro; Kojima, Seiji; Sudo, Yuki; Asami, Yasuo; Homma, Michio
2013-01-01
Flagellar motors embedded in bacterial membranes are molecular machines powered by specific ion flows. Each motor is composed of a stator and a rotor and the interactions of those components are believed to generate the torque. Na+ influx through the PomA/PomB stator complex of Vibrio alginolyticus is coupled to torque generation and is speculated to trigger structural changes in the cytoplasmic domain of PomA that interacts with a rotor protein in the C-ring, FliG, to drive the rotation. In this study, we tried to overproduce the cytoplasmic loop of PomA (PomA-Loop), but it was insoluble. Thus, we made a fusion protein with a small soluble tag (GB1) which allowed us to express and characterize the recombinant protein. The structure of the PomA-Loop seems to be very elongated or has a loose tertiary structure. When the PomA-Loop protein was produced in E. coli, a slight dominant effect was observed on motility. We conclude that the cytoplasmic loop alone retains a certain function. PMID:27493537
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Multiple Flow Loop SCADA System Implemented on the Production Prototype Loop
DOE Office of Scientific and Technical Information (OSTI.GOV)
Baily, Scott A.; Dalmas, Dale Allen; Wheat, Robert Mitchell
2015-11-16
The following report covers FY 15 activities to develop supervisory control and data acquisition (SCADA) system for the Northstar Moly99 production prototype gas flow loop. The goal of this effort is to expand the existing system to include a second flow loop with a larger production-sized blower. Besides testing the larger blower, this system will demonstrate the scalability of our solution to multiple flow loops.
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Open and closed loop manipulation of charged microchiplets in an electric field
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lu, J. P., E-mail: jplu@parc.com; Thompson, J. D.; Whiting, G. L.
We demonstrate the ability to orient, position, and transport microchips (“chiplets”) with electric fields. In an open-loop approach, modified four phase traveling wave potential patterns manipulate chiplets in a dielectric solution using dynamic template agitation techniques. Repeatable parallel assembly of chiplets is demonstrated to a positional accuracy of 6.5 μm using electrodes of 200 μm pitch. Chiplets with dipole surface charge patterns are used to show that orientation can be controlled by adding unique charge patterns on the chiplets. Chip path routing is also demonstrated. With a closed-loop control system approach using video feedback, dielectric, and electrophoretic forces are used to achievemore » positioning accuracy of better than 1 μm with 1 mm pitch driving electrodes. These chip assembly techniques have the potential to enable future printer systems where inputs are electronic chiplets and the output is a functional electronic system.« less
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Pulsed phase locked loop strain monitor
NASA Technical Reports Server (NTRS)
Froggatt, Mark E. (Inventor)
1995-01-01
A pulse phase locked loop system according to the present invention is described. A frequency generator such as a voltage controlled oscillator (VCO) generates an output signal and a reference signal having a frequency equal to that of the output signal. A transmitting gate gates the output frequency signal and this gated signal drives a transmitting transducer which transmits an acoustic wave through a material. A sample/hold samples a signal indicative of the transmitted wave which is received by a receiving transducer. Divide-by-n counters control these gating and sampling functions in response to the reference signal of the frequency generator. Specifically, the output signal is gated at a rate of F/h, wherein F is the frequency of the output signal and h is an integer; and the received signal is sampled at a delay of F/n wherein n is an integer.
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A new driving method for piezo deformable mirrors: open loop control and MOAO made easy
NASA Astrophysics Data System (ADS)
Ouattara, Issa; Gach, Jean-Luc; Amram, Philippe
2016-07-01
This paper presents the design and the realisation of a technique to attenuate the hysteresis nonlinear phenomenon of piezoelectric actuators. Piezoelectric actuator are widely utilised for deformable mirrors used for MOAO and power laser beam shaping techniques. The nonlinearities of piezo are usually iteratively compensa- ted using closed-loop set-ups. In open-loop control, the hysteresis and the creep of the piezo cannot be corrected, thus this nonlinearities must be removed or at least minimised. The concept has been demonstrated on high displacement Amplified Piezoelectric Actuators (APA) mounted in a Fabry-Perot interferometer. The hysteresis attenuation technique aims to assist the Fabry-Perots nano-positioning control system to attain its main scientific specification. In such system, each APA has a maximum stroke of 270 μm within a 170 V (-20 V to +150 V) range and is used to position a high reflective mirror plate. The Fabry-Perots nano-positioning control system is specified to limit the APAs positioning steady-state noise to 3nm rms, but the hysteresis limits the positioning accuracy. In order to attenuate hysteresis, a hybrid amplifier circuit built with a high power operational amplifier has been designed and applied for each APA. The experiments results show that the hysteresis effect has almost been eliminated, and consequently the positioning steady-state noise can significantly been reduced. Because of the excellent results of this hybrid amplifier, a patent application has been introduced in June 12, 2015 under number No.1555381 and is being reviewed now.
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GIANT CORONAL LOOPS DOMINATE THE QUIESCENT X-RAY EMISSION IN RAPIDLY ROTATING M STARS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cohen, O.; Yadav, R.; Garraffo, C.
2017-01-01
Observations indicate that magnetic fields in rapidly rotating stars are very strong, on both small and large scales. What is the nature of the resulting corona? Here we seek to shed some light on this question. We use the results of an anelastic dynamo simulation of a rapidly rotating fully convective M star to drive a physics-based model for the stellar corona. We find that due to the several kilo Gauss large-scale magnetic fields at high latitudes, the corona, and its X-ray emission are dominated by star-size large hot loops, while the smaller, underlying colder loops are not visible muchmore » in the X-ray. Based on this result, we propose that, in rapidly rotating stars, emission from such coronal structures dominates the quiescent, cooler but saturated X-ray emission.« less
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N -loop running should be combined with N -loop matching
NASA Astrophysics Data System (ADS)
Braathen, Johannes; Goodsell, Mark D.; Krauss, Manuel E.; Opferkuch, Toby; Staub, Florian
2018-01-01
We investigate the high-scale behavior of Higgs sectors beyond the Standard Model, pointing out that the proper matching of the quartic couplings before applying the renormalization group equations (RGEs) is of crucial importance for reliable predictions at larger energy scales. In particular, the common practice of leading-order parameters in the RGE evolution is insufficient to make precise statements on a given model's UV behavior, typically resulting in uncertainties of many orders of magnitude. We argue that, before applying N -loop RGEs, a matching should even be performed at N -loop order in contrast to common lore. We show both analytical and numerical results where the impact is sizable for three minimal extensions of the Standard Model: a singlet extension, a second Higgs doublet and finally vector-like quarks. We highlight that the known two-loop RGEs tend to moderate the running of their one-loop counterparts, typically delaying the appearance of Landau poles. For the addition of vector-like quarks we show that the complete two-loop matching and RGE evolution hints at a stabilization of the electroweak vacuum at high energies, in contrast to results in the literature.
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Unmixing Magnetic Hysteresis Loops
NASA Astrophysics Data System (ADS)
Heslop, D.; Roberts, A. P.
2012-04-01
Magnetic hysteresis loops provide important information in rock and environmental magnetic studies. Natural samples often contain an assemblage of magnetic particles composed of components with different origins. Each component potentially carries important environmental information. Hysteresis loops, however, provide information concerning the bulk magnetic assemblage, which makes it difficult to isolate the specific contributions from different sources. For complex mineral assemblages an unmixing strategy with which to separate hysteresis loops into their component parts is therefore essential. Previous methods to unmix hysteresis data have aimed at separating individual loops into their constituent parts using libraries of type-curves thought to correspond to specific mineral types. We demonstrate an alternative approach, which rather than decomposing a single loop into monomineralic contributions, examines a collection of loops to determine their constituent source materials. These source materials may themselves be mineral mixtures, but they provide a genetically meaningful decomposition of a magnetic assemblage in terms of the processes that controlled its formation. We show how an empirically derived hysteresis mixing space can be created, without resorting to type-curves, based on the co-variation within a collection of measured loops. Physically realistic end-members, which respect the expected behaviour and symmetries of hysteresis loops, can then be extracted from the mixing space. These end-members allow the measured loops to be described as a combination of invariant parts that are assumed to represent the different sources in the mixing model. Particular attention is paid to model selection and estimating the complexity of the mixing model, specifically, how many end-members should be included. We demonstrate application of this approach using lake sediments from Butte Valley, northern California. Our method successfully separates the hysteresis loops
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Neuromorphic meets neuromechanics, part II: the role of fusimotor drive
NASA Astrophysics Data System (ADS)
Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Sohn, Won Joon; Loeb, Gerald E.; Sanger, Terence D.; Valero-Cuevas, Francisco J.
2017-04-01
Objective. We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. Approach. As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bi-directional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. Main results. We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. Significance. We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our Neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function—and its
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Neuromorphic Meets Neuromechanics, Part II: The Role of Fusimotor Drive
Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Joon Sohn, Won; Loeb, Gerald E.; Sanger, Terence D.; Valero-Cuevas, Francisco J.
2017-01-01
Objective We studied the fundamentals of muscle afferentation by building a neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. Approach As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bidirectional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. Results We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. Significance We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function — and its pathologies
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Extended driving impairs nocturnal driving performances.
Sagaspe, Patricia; Taillard, Jacques; Akerstedt, Torbjorn; Bayon, Virginie; Espié, Stéphane; Chaumet, Guillaume; Bioulac, Bernard; Philip, Pierre
2008-01-01
Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3-5 am, 1-5 am and 9 pm-5 am) on open highway. Fourteen young healthy men (mean age [+/-SD] = 23.4 [+/-1.7] years) participated Inappropriate line crossings (ILC) in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3-5 am) driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05) for the intermediate (1-5 am) driving session and by 4.0 (CI, 1.7 to 9.4; P<.001) for the long (9 pm-5 am) driving session. Compared to the reference session (9-10 pm), the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001), 15.4 (CI, 4.6 to 51.5; P<.001) and 24.3 (CI, 7.4 to 79.5; P<.001), respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05) and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01). At night, extended driving impairs driving performances and therefore should be limited.
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Data that drive: Closing the loop in the learning hospital system.
Liu, Vincent X; Morehouse, John W; Baker, Jennifer M; Greene, John D; Kipnis, Patricia; Escobar, Gabriel J
2016-11-01
The learning healthcare system describes a vision of US healthcare that capitalizes on science, information technology, incentives, and care culture to drive improvements in the quality of health care. The inpatient setting, one of the most costly and impactful domains of healthcare, is an ideal setting in which to use data and information technology to foster continuous learning and quality improvement. The rapid digitization of inpatient medicine offers incredible new opportunities to use data from routine care to generate new discovery and thus close the virtuous cycle of learning. We use an object lesson-sepsis care within the 21 hospitals of the Kaiser Permanente Northern California integrated healthcare delivery system-to offer insight into the critical elements necessary for developing a learning hospital system. We then describe how a hospital-wide data-driven approach to inpatient care can facilitate improvements in the quality of hospital care. Journal of Hospital Medicine 2016;11:S11-S17. © 2016 Society of Hospital Medicine. © 2016 Society of Hospital Medicine.
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Golebiowski, Jérôme; Antonczak, Serge; Fernandez-Carmona, Juan; Condom, Roger; Cabrol-Bass, Daniel
2004-12-01
Nanosecond molecular dynamics using the Ewald summation method have been performed to elucidate the structural and energetic role of the closing base pair in loop-loop RNA duplexes neutralized by Mg2+ counterions in aqueous phases. Mismatches GA, CU and Watson-Crick GC base pairs have been considered for closing the loop of an RNA in complementary interaction with HIV-1 TAR. The simulations reveal that the mismatch GA base, mediated by a water molecule, leads to a complex that presents the best compromise between flexibility and energetic contributions. The mismatch CU base pair, in spite of the presence of an inserted water molecule, is too short to achieve a tight interaction at the closing-loop junction and seems to force TAR to reorganize upon binding. An energetic analysis has allowed us to quantify the strength of the interactions of the closing and the loop-loop pairs throughout the simulations. Although the water-mediated GA closing base pair presents an interaction energy similar to that found on fully geometry-optimized structure, the water-mediated CU closing base pair energy interaction reaches less than half the optimal value.
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Coupled dual loop absorption heat pump
Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.
1985-01-01
A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.
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The diversity of H3 loops determines the antigen-binding tendencies of antibody CDR loops.
Tsuchiya, Yuko; Mizuguchi, Kenji
2016-04-01
Of the complementarity-determining regions (CDRs) of antibodies, H3 loops, with varying amino acid sequences and loop lengths, adopt particularly diverse loop conformations. The diversity of H3 conformations produces an array of antigen recognition patterns involving all the CDRs, in which the residue positions actually in contact with the antigen vary considerably. Therefore, for a deeper understanding of antigen recognition, it is necessary to relate the sequence and structural properties of each residue position in each CDR loop to its ability to bind antigens. In this study, we proposed a new method for characterizing the structural features of the CDR loops and obtained the antigen-binding ability of each residue position in each CDR loop. This analysis led to a simple set of rules for identifying probable antigen-binding residues. We also found that the diversity of H3 loop lengths and conformations affects the antigen-binding tendencies of all the CDR loops. © 2016 The Protein Society.
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Guan, Liu; Zhao, Jiahao; Yu, Shijie; Li, Peng; You, Zheng
2010-01-01
Micro-cantilever sensors for mass detection using resonance frequency have attracted considerable attention over the last decade in the field of gas sensing. For such a sensing system, an oscillator circuit loop is conventionally used to actuate the micro-cantilever, and trace the frequency shifts. In this paper, gas experiments are introduced to investigate the mechanical resonance frequency shifts of the micro-cantilever within the circuit loop(mechanical resonance frequency, MRF) and resonating frequency shifts of the electric signal in the oscillator circuit (system working frequency, SWF). A silicon beam with a piezoelectric zinc oxide layer is employed in the experiment, and a Self-Actuating-Detecting (SAD) circuit loop is built to drive the micro-cantilever and to follow the frequency shifts. The differences between the two resonating frequencies and their shifts are discussed and analyzed, and a coefficient α related to the two frequency shifts is confirmed. PMID:22163588
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A Fabry-Pérot electro-optic sensing system using a drive-current-tuned wavelength laser diode.
Kuo, Wen-Kai; Wu, Pei-Yu; Lee, Chang-Ching
2010-05-01
A Fabry-Pérot enhanced electro-optic sensing system that utilizes a drive-current-tuned wavelength laser diode is presented. An electro-optic prober made of LiNbO(3) crystal with an asymmetric Fabry-Pérot cavity is used in this system. To lock the wavelength of the laser diode at resonant condition, a closed-loop power control scheme is proposed. Experiment results show that the system can keep the electro-optic prober at high sensitivity for a long working time when the closed-loop control function is on. If this function is off, the sensitivity may be fluctuated and only one-third of the best level in the worst case.
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Massless spectra and gauge couplings at one-loop on non-factorisable toroidal orientifolds
NASA Astrophysics Data System (ADS)
Berasaluce-González, Mikel; Honecker, Gabriele; Seifert, Alexander
2018-01-01
So-called 'non-factorisable' toroidal orbifolds can be rewritten in a factorised form as a product of three two-tori by imposing an additional shift symmetry. This finding of Blaszczyk et al. [1] provides a new avenue to Conformal Field Theory methods, by which the vector-like massless matter spectrum - and thereby the type of gauge group enhancement on orientifold invariant fractional D6-branes - and the one-loop corrections to the gauge couplings in Type IIA orientifold theories can be computed in addition to the well-established chiral matter spectrum derived from topological intersection numbers among three-cycles. We demonstrate this framework for the Z4 × ΩR orientifolds on the A3 ×A1 ×B2-type torus. As observed before for factorisable backgrounds, also here the one-loop correction can drive the gauge groups to stronger coupling as demonstrated by means of a four-generation Pati-Salam example.
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Power flow control based solely on slow feedback loop for heart pump applications.
Wang, Bob; Hu, Aiguo Patrick; Budgett, David
2012-06-01
This paper proposes a new control method for regulating power flow via transcutaneous energy transfer (TET) for implantable heart pumps. Previous work on power flow controller requires a fast feedback loop that needs additional switching devices and resonant capacitors to be added to the primary converter. The proposed power flow controller eliminates these additional components, and it relies solely on a slow feedback loop to directly drive the primary converter to meet the heart pump power demand and ensure zero voltage switching. A controlled change in switching frequency varies the resonant tank shorting period of a current-fed push-pull resonant converter, thus changing the magnitude of the primary resonant voltage, as well as the tuning between primary and secondary resonant tanks. The proposed controller has been implemented successfully using an analogue circuit and has reached an end-to-end power efficiency of 79.6% at 10 W with a switching frequency regulation range of 149.3 kHz to 182.2 kHz.
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Hard-thermal-loop perturbation theory to two loops
NASA Astrophysics Data System (ADS)
Andersen, Jens O.; Braaten, Eric; Petitgirard, Emmanuel; Strickland, Michael
2002-10-01
We calculate the pressure for pure-glue QCD at high temperature to two-loop order using hard-thermal-loop (HTL) perturbation theory. At this order, all the ultraviolet divergences can be absorbed into renormalizations of the vacuum energy density and the HTL mass parameter. We determine the HTL mass parameter by a variational prescription. The resulting predictions for the pressure fail to agree with results from lattice gauge theory at temperatures for which they are available.
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NASA Astrophysics Data System (ADS)
Vilar, Jose M. G.; Saiz, Leonor
2006-06-01
DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switchlike transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.
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Zhang, Xuena; Wu, Anshi; Yao, Shanglong; Xue, Zhanggang; Yue, Yun
2015-01-01
Background The CONCERT-CL closed-loop infusion system designed by VERYARK Technology Co., Ltd. (Guangxi, China) is an innovation using TCI combined with closed-loop controlled intravenous anesthesia under the guide of BIS. In this study we performed a randomized, controlled, multicenter study to compare closed-loop control and open-loop control of propofol by using the CONCERT-CL closed-loop infusion system. Methods 180 surgical patients from three medical centers undergone TCI intravenous anesthesia with propofol and remifentanil were randomly assigned to propofol closed-loop group and propofol opened-loop groups. Primary outcome was global score (GS, GS = (MDAPE+Wobble)/% of time of bispectral index (BIS) 40-60). Secondary outcomes were doses of the anesthetics and emergence time from anesthesia, such as, time to tracheal extubation. Results There were 89 and 86 patients in the closed-loop and opened-loop groups, respectively. GS in the closed-loop groups (22.21±8.50) were lower than that in the opened-loop group (27.19±15.26) (p=0.009). The higher proportion of time of BIS between 40 and 60 was also observed in the closed-loop group (84.11±9.50%), while that was 79.92±13.17% in the opened-loop group, (p=0.016). No significant differences in propofol dose and time of tracheal extubation were observed. The frequency of propofol regulation in the closed-loop group (31.55±9.46 times/hr) was obverse higher than that in the opened-loop group (6.84±6.21 times/hr) (p=0.000). Conclusion The CONCERT-CL closed-loop infusion system can automatically regulate the TCI of propofol, maintain the BIS value in an adequate range and reduce the workload of anesthesiologists better than open-loop system. Trial Registration ChiCTR ChiCTR-OOR-14005551 PMID:25886041
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Loop-loop interactions govern multiple steps in indole-3-glycerol phosphate synthase catalysis
Zaccardi, Margot J; O'Rourke, Kathleen F; Yezdimer, Eric M; Loggia, Laura J; Woldt, Svenja; Boehr, David D
2014-01-01
Substrate binding, product release, and likely chemical catalysis in the tryptophan biosynthetic enzyme indole-3-glycerol phosphate synthase (IGPS) are dependent on the structural dynamics of the β1α1 active-site loop. Statistical coupling analysis and molecular dynamic simulations had previously indicated that covarying residues in the β1α1 and β2α2 loops, corresponding to Arg54 and Asn90, respectively, in the Sulfolobus sulfataricus enzyme (ssIGPS), are likely important for coordinating functional motions of these loops. To test this hypothesis, we characterized site mutants at these positions for changes in catalytic function, protein stability and structural dynamics for the thermophilic ssIGPS enzyme. Although there were only modest changes in the overall steady-state kinetic parameters, solvent viscosity and solvent deuterium kinetic isotope effects indicated that these amino acid substitutions change the identity of the rate-determining step across multiple temperatures. Surprisingly, the N90A substitution had a dramatic effect on the general acid/base catalysis of the dehydration step, as indicated by the loss of the descending limb in the pH rate profile, which we had previously assigned to Lys53 on the β1α1 loop. These changes in enzyme function are accompanied with a quenching of ps-ns and µs-ms timescale motions in the β1α1 loop as measured by nuclear magnetic resonance studies. Altogether, our studies provide structural, dynamic and functional rationales for the coevolution of residues on the β1α1 and β2α2 loops, and highlight the multiple roles that the β1α1 loop plays in IGPS catalysis. Thus, substitution of covarying residues in the active-site β1α1 and β2α2 loops of indole-3-glycerol phosphate synthase results in functional, structural, and dynamic changes, highlighting the multiple roles that the β1α1 loop plays in enzyme catalysis and the importance of regulating the structural dynamics of this loop through noncovalent
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Current Sensor Fault Reconstruction for PMSM Drives
Huang, Gang; Luo, Yi-Ping; Zhang, Chang-Fan; He, Jing; Huang, Yi-Shan
2016-01-01
This paper deals with a current sensor fault reconstruction algorithm for the torque closed-loop drive system of an interior PMSM. First, sensor faults are equated to actuator ones by a new introduced state variable. Then, in αβ coordinates, based on the motor model with active flux linkage, a current observer is constructed with a specific sliding mode equivalent control methodology to eliminate the effects of unknown disturbances, and the phase current sensor faults are reconstructed by means of an adaptive method. Finally, an αβ axis current fault processing module is designed based on the reconstructed value. The feasibility and effectiveness of the proposed method are verified by simulation and experimental tests on the RT-LAB platform. PMID:26840317
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Tsai, Yu-Cheng; Cooke, Nancy E.; Liebhaber, Stephen A.
2016-01-01
Abstract The relationships of higher order chromatin organization to mammalian gene expression remain incompletely defined. The human Growth Hormone (hGH) multigene cluster contains five gene paralogs. These genes are selectively activated in either the pituitary or the placenta by distinct components of a remote locus control region (LCR). Prior studies have revealed that appropriate activation of the placental genes is dependent not only on the actions of the LCR, but also on the multigene composition of the cluster itself. Here, we demonstrate that the hGH LCR ‘loops’ over a distance of 28 kb in primary placental nuclei to make specific contacts with the promoters of the two GH genes in the cluster. This long-range interaction sequesters the GH genes from the three hCS genes which co-assemble into a tightly packed ‘hCS chromatin hub’. Elimination of the long-range looping, via specific deletion of the placental LCR components, triggers a dramatic disruption of the hCS chromatin hub. These data reveal a higher-order structural pathway by which long-range looping from an LCR impacts on local chromatin architecture that is linked to tissue-specific gene regulation within a multigene cluster. PMID:26893355
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Hartwich, Franziska; Beggiato, Matthias; Krems, Josef F
2018-02-23
Automated driving has the potential to improve the safety and efficiency of future traffic and to extend elderly peoples' driving life, provided it is perceived as comfortable and joyful and is accepted by drivers. Driving comfort could be enhanced by familiar automated driving styles based on drivers' manual driving styles. In a two-stage driving simulator study, effects of driving automation and driving style familiarity on driving comfort, enjoyment and system acceptance were examined. Twenty younger and 20 older drivers performed a manual and four automated drives of different driving style familiarity. Acceptance, comfort and enjoyment were assessed after driving with standardised questionnaires, discomfort during driving via handset control. Automation increased both age groups' comfort, but decreased younger drivers' enjoyment. Younger drivers showed higher comfort, enjoyment and acceptance with familiar automated driving styles, whereas older drivers preferred unfamiliar, automated driving styles tending to be faster than their age-affected manual driving styles. Practitioner Summary: Automated driving needs to be comfortable and enjoyable to be accepted by drivers, which could be enhanced by driving style individualisation. This approach was evaluated in a two-stage driving simulator study for different age groups. Younger drivers preferred familiar driving styles, whereas older drivers preferred driving styles unaffected by age.
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Fiber lasers with loop reflectors.
Urquhart, P
1989-09-01
The theory of homogeneously broadened four level fiber lasers, which use fiber loops as distributed reflective elements, is examined. Such cavities can be made entirely from rare earth doped fiber. The amplifying characteristics of doped fiber loops are examined. The threshold pump power and the loop reflectivity necessary to optimize the lasing output power from an oscillator formed from two loops in series are predicted.
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Shang, Jer-Yu; Mei, Joseph S.; Slagle, Frank D.; Notestein, John E.
1984-01-01
The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.
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Glaucoma and Driving: On-Road Driving Characteristics
Wood, Joanne M.; Black, Alex A.; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia
2016-01-01
Purpose To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Methods Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Results Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Conclusions Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness. PMID:27472221
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Glaucoma and Driving: On-Road Driving Characteristics.
Wood, Joanne M; Black, Alex A; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia
2016-01-01
To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sabau, Adrian; Wright, Ian
Boiler tubes in steam power plants experience tube blockages due to exfoliation of oxide grown on the inner side of the tubes. In extreme cases, significant tube blockages can lead to forced power plant outages. It is thus desired to predict through modeling the amount of tube blockage in order to inform power plant operators of possible forced outages. SpalLoop solves for the stress-strain equations in an axisymmetric geometry, tracking the stress/strain evolution during boiler operation including outages for the entire boiler tube length. At each operational outage, i.e., temperature excursions down to room temperature, the amount of exfoliated areamore » for the entire tube loop is estimated the amount of tube blockage is predicted based assumed blockage geometry and site. The SpaLLoop code contains modules developed for oxide growth, stress analysis, tube loop geometry, blockage area by taking into account the following phenomena and features, (a) Plant operation schedule with periodic alternate full-load and partial-load regimes and shut-downs, i.e., temperature excursions from high-load to room temperature, (b) axisymmetric formulation for cylindrical tubes, (c) oxide growth in a temperature gradient with multiple oxide layers, (d) geometry of a boiler tube with a single tube loop or two tube loops, (e) temperature variation along the tube length based on hot gas temperature distribution outside the tube and inlet steam temperature, (f) non-uniform oxide growth along the tube length according to the local steam tube temperature, (g) exfoliated area module: at each operational outage considered, the amount of exfoliated area and exfoliated volume along the tube is estimated, (h) blockage module: at each operational outage considered, the exfoliated volume/mass for each tube loop is estimated from which the amount of tube blockage is predicted based on given blockage geometry (length, location, and geometry). The computer program is written in FORTRAN90. Its
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Bandwidth controller for phase-locked-loop
NASA Technical Reports Server (NTRS)
Brockman, Milton H. (Inventor)
1992-01-01
A phase locked loop utilizing digital techniques to control the closed loop bandwidth of the RF carrier phase locked loop in a receiver provides high sensitivity and a wide dynamic range for signal reception. After analog to digital conversion, a digital phase locked loop bandwidth controller provides phase error detection with automatic RF carrier closed loop tracking bandwidth control to accommodate several modes of transmission.
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Ge, Yan; Zhang, Qian; Zhao, Wenguo; Zhang, Kan; Qu, Weina
2017-11-01
To explore the effect of anger behind the wheel on driving behavior and accident involvement has been the subject of many studies. However, few studies have explored the interaction between anger and driving experience on dangerous driving behavior. This study is a moderated mediation analysis of the effect of trait anger, driving anger, and driving experience on driving behavior. A sample of 303 drivers was tested using the Trait Anger Scale (TAS), the Driving Anger Scale (DAS), and the Dula Dangerous Driving Index (DDDI). The results showed that trait anger and driving anger were positively correlated with dangerous driving behavior. Driving anger partially mediated the effect of trait anger on dangerous driving behavior. Driving experience moderated the relationship between trait anger and driving anger. It also moderated the effect of driving anger on dangerous driving behavior. These results suggest that drivers with more driving experience may be safer as they are not easily irritated during driving. © 2017 Wiley Periodicals, Inc.
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NASA Astrophysics Data System (ADS)
Xiao, Dingbang; Su, Jianbin; Chen, Zhihua; Hou, Zhanqiang; Wang, Xinghua; Wu, Xuezhong
2013-04-01
In order to improve its structural sensitivity, a vibratory microgyroscope is commonly sealed in high vacuum to increase the drive mode quality factor. The sense mode quality factor of the microgyroscope will also increase simultaneously after vacuum sealing, which will lead to a long decay time of free response and even self-oscillation of the sense mode. As a result, the mechanical performance of the microgyroscope will be seriously degraded. In order to solve this problem, a closed-loop control technique is presented to adjust and optimize the sense mode quality factor. A velocity feedback loop was designed to increase the electric damping of the sense mode vibration. A circuit was fabricated based on this technique, and experimental results indicate that the sense mode quality factor of the microgyroscope was adjusted from 8052 to 428. The decay time of the sense mode free response was shortened from 3 to 0.5 s, and the vibration-rejecting ability of the microgyroscope was improved obviously without sensitivity degradation.
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NASA Technical Reports Server (NTRS)
Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros
2008-01-01
One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense warm loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.
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Intelligent vehicle safety control strategy in various driving situations
NASA Astrophysics Data System (ADS)
Moon, Seungwuk; Cho, Wanki; Yi, Kyongsu
2010-12-01
This paper describes a safety control strategy for intelligent vehicles with the objective of optimally coordinating the throttle, brake, and active front steering actuator inputs to obtain both lateral stability and longitudinal safety. The control system consists of a supervisor, control algorithms, and a coordinator. From the measurement and estimation signals, the supervisor determines the active control modes among normal driving, longitudinal safety, lateral stability, and integrated safety control mode. The control algorithms consist of longitudinal and lateral stability controllers. The longitudinal controller is designed to improve the driver's comfort during normal, safe-driving situations, and to avoid rear-end collision in vehicle-following situations. The lateral stability controller is designed to obtain the required manoeuvrability and to limit the vehicle body's side-slip angle. To obtain both longitudinal safety and lateral stability control in various driving situations, the coordinator optimally determines the throttle, brake, and active front steering inputs based on the current status of the subject vehicle. Closed-loop simulations with the driver-vehicle-controller system are conducted to investigate the performance of the proposed control strategy. From these simulation results, it is shown that the proposed control algorithm assists the driver in combined severe braking/large steering manoeuvring so that the driver can maintain good manoeuvrability and prevent the vehicle from crashing in vehicle-following situations.
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RCD+: Fast loop modeling server.
López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo
2016-07-08
Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.
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NASA Astrophysics Data System (ADS)
Wang, Wanjun; He, Tian
1996-01-01
A five degrees of freedom high precision micropositioner based on spring suspension and electromagnetic driving has been designed, constructed, and tested. The device consists of two parts: a moving part and a stationary part. The moving part, named as ``motor'', is formed with a rigid frame and three groups of coils fixed on it. The stationary part of the device, called ``stator'', includes a chassis and twelve U-shaped magnetic ``shoes''. The motor is attached to the stator with flat springs whose linear suspension allows it to move in all dimensions except the rotation around z axis. The coils have been laid out in such a way that fractions of them pass through the air gaps between the facing magnets in the magnetic shoes. When electrical currents are supplied to the coils, the resulting Lorenz forces drive the motor to move in the five degrees of freedom allowed by the spring suspension. Since the system is inherently stable and there is no mechanical friction, the open-loop resolutions of the device are found to be limited only by that of the 12-bit D/A board used. A closed-loop translation resolution of 0.3 μm has been achieved over a working space of 180 μm by 180 μm by 680 μm. A closed-loop rotation resolution of 2.73×10-6 rad has been achieved over a working space of 1.38×10-3 rad. Potentially the device can be used for high precision microprobing and testing, cellular biology, microsurgery, and testing of micromechanical devices in the fast developing MEMS area.
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Fragmentation of cosmic-string loops
NASA Technical Reports Server (NTRS)
York, Thomas
1989-01-01
The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. Such reconnection enhances the production of small fragments, but not drastically. With or without reconnections, the fragmentation process produces a collection of nonself-intersecting loops whose typical length is on the order of the persistence length of the initial loop.
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Particle pinch with fully noninductive lower hybrid current drive in Tore Supra.
Hoang, G T; Bourdelle, C; Pégourié, B; Schunke, B; Artaud, J F; Bucalossi, J; Clairet, F; Fenzi-Bonizec, C; Garbet, X; Gil, C; Guirlet, R; Imbeaux, F; Lasalle, J; Loarer, T; Lowry, C; Travère, J M; Tsitrone, E
2003-04-18
Recently, plasmas exceeding 4 min have been obtained with lower hybrid current drive (LHCD) in Tore Supra. These LHCD plasmas extend for over 80 times the resistive current diffusion time with zero loop voltage. Under such unique conditions the neoclassical particle pinch driven by the toroidal electric field vanishes. Nevertheless, the density profile remains peaked for more than 4 min. For the first time, the existence of an inward particle pinch in steady-state plasma without toroidal electric field, much larger than the value predicted by the collisional neoclassical theory, is experimentally demonstrated.
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Chaumeil, Julie; Micsinai, Mariann; Ntziachristos, Panagiotis; Deriano, Ludovic; Wang, Joy M-H; Ji, Yanhong; Nora, Elphege P.; Rodesch, Matthew J.; Jeddeloh, Jeffrey A.; Aifantis, Iannis; Kluger, Yuval; Schatz, David G.; Skok, Jane A.
2013-01-01
SUMMARY V(D)J recombination is essential for generating a diverse array of B and T cell receptors that can recognize and combat foreign antigen. As with any recombination event, tight control is essential to prevent the occurrence of genetic anomalies that drive cellular transformation. One important aspect of regulation is directed targeting of the RAG recombinase. Indeed, RAG accumulates at the 3’ end of individual antigen receptor loci poised for rearrangement, however, it is not known whether focal binding is involved in regulating cleavage, and what mechanisms lead to enrichment of RAG in this region. Here we show that mono-allelic looping out of the 3’ end of Tcra, coupled with transcription and increased chromatin/nuclear accessibility, are linked to focal RAG binding and ATM-mediated regulated mono-allelic cleavage on looped out 3’ regions. Our data identify higher order loop formation as a key determinant of directed RAG targeting and the maintenance of genome stability. PMID:23416051
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Suppressing Transients In Digital Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Thomas, J. B.
1993-01-01
Loop of arbitrary order starts in steady-state lock. Method for initializing variables of digital phase-locked loop reduces or eliminates transients in phase and frequency typically occurring during acquisition of lock on signal or when changes made in values of loop-filter parameters called "loop constants". Enables direct acquisition by third-order loop without prior acquisition by second-order loop of greater bandwidth, and eliminates those perturbations in phase and frequency lock occurring when loop constants changed by arbitrarily large amounts.
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Towards the use of Structural Loop Analysis to Study System Behaviour of Socio-Ecological Systems.
NASA Astrophysics Data System (ADS)
Abram, Joseph; Dyke, James
2016-04-01
Maintaining socio-ecological systems in desirable states is key to developing a growing economy, alleviating poverty and achieving a sustainable future. While the driving forces of an environmental system are often well known, the dynamics impacting these drivers can be hidden within a tangled structure of causal chains and feedback loops. A lack of understanding of a system's dynamic structure and its influence on a system's behaviour can cause unforeseen side-effects during model scenario testing and policy implementation. Structural Loop analysis of socio-ecological system models identifies dominant feedback structures during times of behavioural shift, allowing the user to monitor key influential drivers during model simulation. This work carries out Loop Eigenvalue Elasticity Analysis (LEEA) on three system dynamic models, exploring tipping points in lake systems undergoing eutrophication. The purpose is to explore the potential benefits and limitations of the technique in the field of socio-ecology. The LEEA technique shows promise for socio-ecological systems which undergo regime shifts or express oscillatory trends, but shows limited usefulness with large models. The results of this work highlight changes in feedback loop dominance, years prior to eutrophic tipping events in lake systems. LEEA could be used as an early warning signal to impending system changes, complementary to other known early warning signals. This approach could improve our understanding during critical times of a system's behaviour, changing how we approach model analysis and the way scenario testing and policy implementation are addressed in socio-ecological system models.
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Self-rated Driving and Driving Safety in Older Adults
Ross, Lesley A.; Dodson, Joan; Edwards, Jerri D.; Ackerman, Michelle L.; Ball, Karlene
2012-01-01
Many U.S. states rely on older adults to self-regulate their driving and determine when driving is no longer a safe option. However, the relationship of older adults’ self-rated driving in terms of actual driving competency outcomes is unclear. The current study investigates self-rated driving in terms of (1) systematic differences between older adults with high (good/excellent) versus low (poor/fair/average) self-ratings, and (2) the predictive nature of self-rated driving to adverse driving outcomes in older drivers (n=350; mean age 73.9, SD=5.25, range 65–91). Adverse driving outcomes included self-reported incidences of (1) being pulled over by the police, (2) receiving a citation, (3) receiving a recommendation to cease or limit driving, (4) crashes, and (5) state-reported crashes. Results found that older drivers with low self-ratings reported more medical conditions, less driving frequency, and had been given more suggestions to stop/limit their driving; there were no other significant differences between low and high self-raters. Logistic regression revealed older drivers were more likely to have a state-reported crash and receive a suggestion to stop or limit driving. Men were more likely to report all adverse driving outcomes except for receiving a suggestion to stop or limit driving. Regarding self-rated driving, older adults with high ratings were 66% less likely (OR=0.34, 95% CI=0.14–0.85) to have received suggestions to limit or stop driving after accounting for demographics, health and driving frequency. Self-ratings were not predictive of other driving outcomes (being pulled over by the police, receiving a citation, self-reported crashes, or state-reported crashes, ps>.05). Most older drivers (85.14%) rated themselves as either good or excellent drivers regardless of their actual previous citation or crash rates. Self-rated driving is likely not related to actual driving proficiency as indicated by previous crash involvement in older adults
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Closed Loop Control of a Tethered Magnetic Capsule Endoscope
Taddese, Addisu Z.; Slawinski, Piotr R.; Obstein, Keith L.; Valdastri, Pietro
2017-01-01
Magnetic field gradients have repeatedly been shown to be the most feasible mechanism for gastrointestinal capsule endoscope actuation. An inverse quartic magnetic force variation with distance results in large force gradients induced by small movements of a driving magnet; this necessitates robotic actuation of magnets to implement stable control of the device. A typical system consists of a serial robot with a permanent magnet at its end effector that actuates a capsule with an embedded permanent magnet. We present a tethered capsule system where a capsule with an embedded magnet is closed loop controlled in 2 degree-of-freedom in position and 2 degree-of-freedom in orientation. Capitalizing on the magnetic field of the external driving permanent magnet, the capsule is localized in 6-D allowing for both position and orientation feedback to be used in a control scheme. We developed a relationship between the serial robot's joint parameters and the magnetic force and torque that is exerted onto the capsule. Our methodology was validated both in a dynamic simulation environment where a custom plug-in for magnetic interaction was written, as well as on an experimental platform. The tethered capsule was demonstrated to follow desired trajectories in both position and orientation with accuracy that is acceptable for colonoscopy. PMID:28286886
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Closed Loop Control of a Tethered Magnetic Capsule Endoscope.
Taddese, Addisu Z; Slawinski, Piotr R; Obstein, Keith L; Valdastri, Pietro
2016-06-01
Magnetic field gradients have repeatedly been shown to be the most feasible mechanism for gastrointestinal capsule endoscope actuation. An inverse quartic magnetic force variation with distance results in large force gradients induced by small movements of a driving magnet; this necessitates robotic actuation of magnets to implement stable control of the device. A typical system consists of a serial robot with a permanent magnet at its end effector that actuates a capsule with an embedded permanent magnet. We present a tethered capsule system where a capsule with an embedded magnet is closed loop controlled in 2 degree-of-freedom in position and 2 degree-of-freedom in orientation. Capitalizing on the magnetic field of the external driving permanent magnet, the capsule is localized in 6-D allowing for both position and orientation feedback to be used in a control scheme. We developed a relationship between the serial robot's joint parameters and the magnetic force and torque that is exerted onto the capsule. Our methodology was validated both in a dynamic simulation environment where a custom plug-in for magnetic interaction was written, as well as on an experimental platform. The tethered capsule was demonstrated to follow desired trajectories in both position and orientation with accuracy that is acceptable for colonoscopy.
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Study of the Open Loop and Closed Loop Oscillator Techniques
DOE Office of Scientific and Technical Information (OSTI.GOV)
Imel, George R.; Baker, Benjamin; Riley, Tony
This report presents the progress and completion of a five-year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques.The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this report we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign tomore » measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems.« less
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Study of the open loop and closed loop oscillator techniques
DOE Office of Scientific and Technical Information (OSTI.GOV)
Baker, Benjamin; Riley, Tony; Langbehn, Adam
This paper presents some aspects of a five year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques. The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this paper we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign tomore » measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems. (authors)« less
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Automatic inoculating apparatus. [includes movable carraige, drive motor, and swabbing motor
NASA Technical Reports Server (NTRS)
Wilkins, J. R.; Mills, S. M. (Inventor)
1974-01-01
An automatic inoculating apparatus for agar trays is described and using a simple inoculating element, such as a cotton swab or inoculating loop. The apparatus includes a movable carriage for supporting the tray to be inoculated, a drive motor for moving the tray along a trackway, and a swabbing motor for automatically swabbing the tray during the movement. An actuator motor controls lowering of the inoculating element onto the tray and lifting of the inoculating element. An electrical control system, including limit microswitches, enables automatic control of the actuator motor and return of the carriage to the initial position after inoculating is completed.
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A drive unit for the instrument pointing system
NASA Technical Reports Server (NTRS)
Birner, R.; Roth, M.
1981-01-01
The requirements, capabilities, and unique design features of the instrument pointing system drive units (DU) are presented. The DU's are identical for all three gimbal axes (elevation, cross elevation, and azimuth) and provide alternating rotation of shaft versus the housing of + or - 180 deg. The design features include: two ball bearing cartridges using cemented carbide balls coated with TiC a layer; redundant brushless torque motors and resolvers; a load by-pass mechanism driven by a dc torque motor to off-load the bearings during ascent/descent, ground transportation, and to provide an emergency breaking capability; and cabling over each gimbal axis by means of cable follow-up consisting of 13 signal and 15 power flat band cable loops. Test results of disturbance torque characteristics are presented.
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Compact vehicle drive module having improved thermal control
Meyer, Andreas A.; Radosevich, Lawrence D.; Beihoff, Bruce C.; Kehl, Dennis L.; Kannenberg, Daniel G.
2006-01-03
An electric vehicle drive includes a thermal support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support, which may be controlled in a closed-loop manner. Interfacing between circuits, circuit mounting structure, and the support provide for greatly enhanced cooling. The support may form a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.
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Design and Modeling of a Liquid Lithium LiMIT Loop
NASA Astrophysics Data System (ADS)
Szott, Matthew; Christenson, Michael; Stemmley, Steven; Ahn, Chisung; Andruczyk, Daniel; Ruzic, David
2017-10-01
The use of flowing liquid lithium in plasma facing components has been shown to reduce erosion and thermal stress damage, prolong device lifetime, decrease edge recycling, reduce impurities, and increase plasma performance, all while providing a clean and self-healing surface. The Liquid Metal Infused Trench (LiMIT) system has proven the concept of controlled thermoelectric magnetohydrodynamic-driven lithium flow for use in fusion relevant conditions, through tests at UIUC, HT-7, and Magnum PSI. As the use of liquid lithium in fusion devices progresses, emphasis must now be placed on full systems integration of flowing liquid metal concepts. The LiMIT system will be upgraded to include a full liquid lithium loop, which will pump lithium into the fusion device, utilize TEMHD to drive lithium through the vessel, and remove lithium for filtration and degassing. Flow control concepts recently developed at UIUC - including wetting control, dryout control, and flow velocity control - will be tested in conjunction in order to demonstrate a robust system. Lithium loop system requirements, designs, and modeling work will be presented, along with plans for installation and testing on the HIDRA device at UIUC. This work is supported by DOE/ALPS DE-FG02-99ER54515.
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Can arousing feedback rectify lapses in driving? Prediction from EEG power spectra.
Lin, Chin-Teng; Huang, Kuan-Chih; Chuang, Chun-Hsiang; Ko, Li-Wei; Jung, Tzyy-Ping
2013-10-01
This study explores the neurophysiological changes, measured using an electroencephalogram (EEG), in response to an arousing warning signal delivered to drowsy drivers, and predicts the efficacy of the feedback based on changes in the EEG. Eleven healthy subjects participated in sustained-attention driving experiments. The driving task required participants to maintain their cruising position and compensate for randomly induced lane deviations using the steering wheel, while their EEG and driving performance were continuously monitored. The arousing warning signal was delivered to participants who experienced momentary behavioral lapses, failing to respond rapidly to lane-departure events (specifically the reaction time exceeded three times the alert reaction time). The results of our previous studies revealed that arousing feedback immediately reversed deteriorating driving performance, which was accompanied by concurrent EEG theta- and alpha-power suppression in the bilateral occipital areas. This study further proposes a feedback efficacy assessment system to accurately estimate the efficacy of arousing warning signals delivered to drowsy participants by monitoring the changes in their EEG power spectra immediately thereafter. The classification accuracy was up 77.8% for determining the need for triggering additional warning signals. The findings of this study, in conjunction with previous studies on EEG correlates of behavioral lapses, might lead to a practical closed-loop system to predict, monitor and rectify behavioral lapses of human operators in attention-critical settings.
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Joosten, Simon A; Landry, Shane A; Sands, Scott A; Terrill, Philip I; Mann, Dwayne; Andara, Christopher; Skuza, Elizabeth; Turton, Anthony; Berger, Philip; Hamilton, Garun S; Edwards, Bradley A
2017-11-01
Obstructive sleep apnoea (OSA) is typically worse in the supine versus lateral sleeping position. One potential factor driving this observation is a decrease in lung volume in the supine position which is expected by theory to increase a key OSA pathogenic factor: dynamic ventilatory control instability (i.e. loop gain). We aimed to quantify dynamic loop gain in OSA patients in the lateral and supine positions, and to explore the relationship between change in dynamic loop gain and change in lung volume with position. Data from 20 patients enrolled in previous studies on the effect of body position on OSA pathogenesis were retrospectively analysed. Dynamic loop gain was calculated from routinely collected polysomnographic signals using a previously validated mathematical model. Lung volumes were measured in the awake state with a nitrogen washout technique. Dynamic loop gain was significantly higher in the supine than in the lateral position (0.77 ± 0.15 vs 0.68 ± 0.14, P = 0.012). Supine functional residual capacity (FRC) was significantly lower than lateral FRC (81.0 ± 15.4% vs 87.3 ± 18.4% of the seated FRC, P = 0.021). The reduced FRC we observed on moving to the supine position was predicted by theory to increase loop gain by 10.2 (0.6, 17.1)%, a value similar to the observed increase of 8.4 (-1.5, 31.0)%. Dynamic loop gain increased by a small but statistically significant amount when moving from the lateral to supine position and this may, in part, contribute to the worsening of OSA in the supine sleeping position. © 2017 Asian Pacific Society of Respirology.
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Self-rated driving and driving safety in older adults.
Ross, Lesley A; Dodson, Joan E; Edwards, Jerri D; Ackerman, Michelle L; Ball, Karlene
2012-09-01
Many U.S. states rely on older adults to self-regulate their driving and determine when driving is no longer a safe option. However, the relationship of older adults' self-rated driving in terms of actual driving competency outcomes is unclear. The current study investigates self-rated driving in terms of (1) systematic differences between older adults with high (good/excellent) versus low (poor/fair/average) self-ratings, and (2) the predictive nature of self-rated driving to adverse driving outcomes in older adults (n=350; mean age 73.9, SD=5.25, range 65-91). Adverse driving outcomes included self-reported incidences of (1) being pulled over by the police, (2) receiving a citation, (3) receiving a recommendation to cease or limit driving, (4) crashes, and (5) state-reported crashes. Results found that older drivers with low self-ratings reported more medical conditions, less driving frequency, and had been given more suggestions to stop/limit their driving; there were no other significant differences between low and high self-raters. Logistic regression revealed older drivers were more likely to have a state-reported crash and receive a suggestion to stop or limit driving. Men were more likely to report all adverse driving outcomes except for receiving a suggestion to stop or limit driving. Regarding self-rated driving, older adults with high ratings were 66% less likely (OR=0.34, 95% CI=0.14-0.85) to have received suggestions to limit or stop driving after accounting for demographics, health and driving frequency. Self-ratings were not predictive of other driving outcomes (being pulled over by the police, receiving a citation, self-reported crashes, or state-reported crashes, ps>0.05). Most older drivers (85.14%) rated themselves as either good or excellent drivers regardless of their actual previous citation or crash rates. Self-rated driving is likely not related to actual driving proficiency as indicated by previous crash involvement in older adults
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Loop Heat Pipe Startup Behaviors
NASA Technical Reports Server (NTRS)
Ku, Jentung
2014-01-01
A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.
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Chemical Looping Technology: Oxygen Carrier Characteristics.
Luo, Siwei; Zeng, Liang; Fan, Liang-Shih
2015-01-01
Chemical looping processes are characterized as promising carbonaceous fuel conversion technologies with the advantages of manageable CO2 capture and high energy conversion efficiency. Depending on the chemical looping reaction products generated, chemical looping technologies generally can be grouped into two types: chemical looping full oxidation (CLFO) and chemical looping partial oxidation (CLPO). In CLFO, carbonaceous fuels are fully oxidized to CO2 and H2O, as typically represented by chemical looping combustion with electricity as the primary product. In CLPO, however, carbonaceous fuels are partially oxidized, as typically represented by chemical looping gasification with syngas or hydrogen as the primary product. Both CLFO and CLPO share similar operational features; however, the optimum process configurations and the specific oxygen carriers used between them can vary significantly. Progress in both CLFO and CLPO is reviewed and analyzed with specific focus on oxygen carrier developments that characterize these technologies.
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NASA Astrophysics Data System (ADS)
Huang, Ann; Miansari, Morteza; Friend, James
The growing interest in acoustic manipulation of particles in micro to nanofluidics using surface acoustic waves (SAW), together with the many applications of magnetic nanoparticles-whether individual or in arrays-underpins our discovery of how these forces can be used to rapidly, easily, and irreversibly form 1D chains and 2D films. These films and chains are currently difficult to produce yet offer many advantages over individual nanoparticles in suspension. Making use of the scale of the structures formed, 10-9 to 10-5 m, and by taking a balance of the relevant external and interparticle forces, the underlying mechanisms responsible for the phenomena become apparent. For 1D chains, the magnetic field alone is sufficient, though applying an acoustic field drives a topology change from loosely connected chains to loops of 10 -100 particles. Adding the acoustic field drives a transition from these looped structures to dense 2D arrays via interparticle Bjerknes forces. Inter-particle drainage of the surrounding fluid leaves these structures intact after removal of the externally applied forces. Clear morphology transitions are present and depend on the relative amplitude of the incident Brownian, Bjerknes, and magnetic forces. UCSD: Frontiers of Innovation Scholars Program (U-1024).
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Transverse Oscillations of Coronal Loops
NASA Astrophysics Data System (ADS)
Ruderman, Michael S.; Erdélyi, Robert
2009-12-01
On 14 July 1998 TRACE observed transverse oscillations of a coronal loop generated by an external disturbance most probably caused by a solar flare. These oscillations were interpreted as standing fast kink waves in a magnetic flux tube. Firstly, in this review we embark on the discussion of the theory of waves and oscillations in a homogeneous straight magnetic cylinder with the particular emphasis on fast kink waves. Next, we consider the effects of stratification, loop expansion, loop curvature, non-circular cross-section, loop shape and magnetic twist. An important property of observed transverse coronal loop oscillations is their fast damping. We briefly review the different mechanisms suggested for explaining the rapid damping phenomenon. After that we concentrate on damping due to resonant absorption. We describe the latest analytical results obtained with the use of thin transition layer approximation, and then compare these results with numerical findings obtained for arbitrary density variation inside the flux tube. Very often collective oscillations of an array of coronal magnetic loops are observed. It is natural to start studying this phenomenon from the system of two coronal loops. We describe very recent analytical and numerical results of studying collective oscillations of two parallel homogeneous coronal loops. The implication of the theoretical results for coronal seismology is briefly discussed. We describe the estimates of magnetic field magnitude obtained from the observed fundamental frequency of oscillations, and the estimates of the coronal scale height obtained using the simultaneous observations of the fundamental frequency and the frequency of the first overtone of kink oscillations. In the last part of the review we summarise the most outstanding and acute problems in the theory of the coronal loop transverse oscillations.
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The Structure of Coronal Loops
NASA Technical Reports Server (NTRS)
Antiochos, Spiro K.
2009-01-01
It is widely believed that the simple coronal loops observed by XUV imagers, such as EIT, TRACE, or XRT, actually have a complex internal structure consisting of many (perhaps hundreds) of unresolved, interwoven "strands". According to the nanoflare model, photospheric motions tangle the strands, causing them to reconnect and release the energy required to produce the observed loop plasma. Although the strands, themselves, are unresolved by present-generation imagers, there is compelling evidence for their existence and for the nanoflare model from analysis of loop intensities and temporal evolution. A problem with this scenario is that, although reconnection can eliminate some of the strand tangles, it cannot destroy helicity, which should eventually build up to observable scales. we consider, therefore, the injection and evolution of helicity by the nanoflare process and its implications for the observed structure of loops and the large-scale corona. we argue that helicity does survive and build up to observable levels, but on spatial and temporal scales larger than those of coronal loops. we discuss the implications of these results for coronal loops and the corona, in general .
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Weidel, Philipp; Djurfeldt, Mikael; Duarte, Renato C; Morrison, Abigail
2016-01-01
In order to properly assess the function and computational properties of simulated neural systems, it is necessary to account for the nature of the stimuli that drive the system. However, providing stimuli that are rich and yet both reproducible and amenable to experimental manipulations is technically challenging, and even more so if a closed-loop scenario is required. In this work, we present a novel approach to solve this problem, connecting robotics and neural network simulators. We implement a middleware solution that bridges the Robotic Operating System (ROS) to the Multi-Simulator Coordinator (MUSIC). This enables any robotic and neural simulators that implement the corresponding interfaces to be efficiently coupled, allowing real-time performance for a wide range of configurations. This work extends the toolset available for researchers in both neurorobotics and computational neuroscience, and creates the opportunity to perform closed-loop experiments of arbitrary complexity to address questions in multiple areas, including embodiment, agency, and reinforcement learning.
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Weidel, Philipp; Djurfeldt, Mikael; Duarte, Renato C.; Morrison, Abigail
2016-01-01
In order to properly assess the function and computational properties of simulated neural systems, it is necessary to account for the nature of the stimuli that drive the system. However, providing stimuli that are rich and yet both reproducible and amenable to experimental manipulations is technically challenging, and even more so if a closed-loop scenario is required. In this work, we present a novel approach to solve this problem, connecting robotics and neural network simulators. We implement a middleware solution that bridges the Robotic Operating System (ROS) to the Multi-Simulator Coordinator (MUSIC). This enables any robotic and neural simulators that implement the corresponding interfaces to be efficiently coupled, allowing real-time performance for a wide range of configurations. This work extends the toolset available for researchers in both neurorobotics and computational neuroscience, and creates the opportunity to perform closed-loop experiments of arbitrary complexity to address questions in multiple areas, including embodiment, agency, and reinforcement learning. PMID:27536234
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Fabrication techniques for superconducting readout loops
NASA Technical Reports Server (NTRS)
Payne, J. E.
1982-01-01
Procedures for the fabrication of superconducting readout loops out of niobium on glass substrates were developed. A computer program for an existing fabrication system was developed. Both positive and negative resist procedures for the production of the readout loops were investigated. Methods used to produce satisfactory loops are described and the various parameters affecting the performance of the loops are analyzed.
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Kadumuri, Rajashekar Varma; Vadrevu, Ramakrishna
2017-10-01
Due to their crucial role in function, folding, and stability, protein loops are being targeted for grafting/designing to create novel or alter existing functionality and improve stability and foldability. With a view to facilitate a thorough analysis and effectual search options for extracting and comparing loops for sequence and structural compatibility, we developed, LoopX a comprehensively compiled library of sequence and conformational features of ∼700,000 loops from protein structures. The database equipped with a graphical user interface is empowered with diverse query tools and search algorithms, with various rendering options to visualize the sequence- and structural-level information along with hydrogen bonding patterns, backbone φ, ψ dihedral angles of both the target and candidate loops. Two new features (i) conservation of the polar/nonpolar environment and (ii) conservation of sequence and conformation of specific residues within the loops have also been incorporated in the search and retrieval of compatible loops for a chosen target loop. Thus, the LoopX server not only serves as a database and visualization tool for sequence and structural analysis of protein loops but also aids in extracting and comparing candidate loops for a given target loop based on user-defined search options.
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NASA Astrophysics Data System (ADS)
Ni, Jun; Hu, Jibin
2017-06-01
In this paper, a novel dynamics controller for autonomous vehicle to simultaneously control it to the driving limits and follow the desired path is proposed. The dynamics controller consists of longitudinal and lateral controllers. In longitudinal controller, the G-G diagram is utilized to describe the driving and handling limits of the vehicle. The accurate G-G diagram is obtained based on phase plane approach and a nonlinear vehicle dynamic model with accurate tyre model. In lateral controller, the tyre cornering stiffness is estimated to improve the robustness of the controller. The stability analysis of the closed-looped error dynamics shows that the controller remains stable against parameters uncertainties in extreme condition such as tyre saturation. Finally, an electric autonomous Formula race car developed by the authors is used to validate the proposed controller. The autonomous driving experiment on an oval race track shows the efficiency and robustness of the proposed controller.
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Coronal loops and active region structure
NASA Technical Reports Server (NTRS)
Webb, D. F.; Zirin, H.
1981-01-01
Synoptic H-alpha Ca K, magnetograph and Skylab soft X-ray and EUV data were compared for the purpose of identifying the basic coronal magnetic structure of loops in a 'typical' active region and studying its evolution. A complex of activity in July 1973, especially McMath 12417, was emphasized. The principal results are: (1) most of the brightest loops connected the bright f plage to either the sunspot penumbra or to p satellite spots; no non-flaring X-ray loops end in umbrae; (2) short, bright loops had one or both ends in regions of emergent flux, strong field or high field gradients; (3) stable, strongly sheared loop arcades formed over filaments; (4) EFRs were always associated with compact X-ray arcades; and (5) loops connecting to other active regions had their bases in outlying plage of weak field strength in McM 417 where H-alpha fibrils marked the direction of the loops
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A Hydrodynamic Model of Alfvénic Wave Heating in a Coronal Loop and Its Chromospheric Footpoints
NASA Astrophysics Data System (ADS)
Reep, Jeffrey W.; Russell, Alexander J. B.; Tarr, Lucas A.; Leake, James E.
2018-02-01
Alfvénic waves have been proposed as an important energy transport mechanism in coronal loops, capable of delivering energy to both the corona and chromosphere and giving rise to many observed features of flaring and quiescent regions. In previous work, we established that resistive dissipation of waves (ambipolar diffusion) can drive strong chromospheric heating and evaporation, capable of producing flaring signatures. However, that model was based on a simplified assumption that the waves propagate instantly to the chromosphere, an assumption that the current work removes. Via a ray-tracing method, we have implemented traveling waves in a field-aligned hydrodynamic simulation that dissipate locally as they propagate along the field line. We compare this method to and validate against the magnetohydrodynamics code Lare3D. We then examine the importance of travel times to the dynamics of the loop evolution, finding that (1) the ionization level of the plasma plays a critical role in determining the location and rate at which waves dissipate; (2) long duration waves effectively bore a hole into the chromosphere, allowing subsequent waves to penetrate deeper than previously expected, unlike an electron beam whose energy deposition rises in height as evaporation reduces the mean-free paths of the electrons; and (3) the dissipation of these waves drives a pressure front that propagates to deeper depths, unlike energy deposition by an electron beam.
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Casutt, Gianclaudio; Theill, Nathan; Martin, Mike; Keller, Martin; Jäncke, Lutz
2014-01-01
Background: Age-related cognitive decline is often associated with unsafe driving behavior. We hypothesized that 10 active training sessions in a driving simulator increase cognitive and on-road driving performance. In addition, driving simulator training should outperform cognitive training. Methods: Ninety-one healthy active drivers (62–87 years) were randomly assigned to one of three groups: (1) a driving simulator training group, (2) an attention training group (vigilance and selective attention), or (3) a control group. The main outcome variables were on-road driving and cognitive performance. Seventy-seven participants (85%) completed the training and were included in the analyses. Training gains were analyzed using a multiple regression analysis with planned orthogonal comparisons. Results: The driving simulator-training group showed an improvement in on-road driving performance compared to the attention-training group. In addition, both training groups increased cognitive performance compared to the control group. Conclusion: Driving simulator training offers the potential to enhance driving skills in older drivers. Compared to the attention training, the simulator training seems to be a more powerful program for increasing older drivers' safety on the road. PMID:24860497
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DriveWise: an interdisciplinary hospital-based driving assessment program.
O'Connor, Margaret G; Kapust, Lissa R; Hollis, Ann M
2008-01-01
Health care professionals working with the elderly have opportunities through research and clinical practice to shape public policy affecting the older driver. This article describes DriveWise, an interdisciplinary hospital-based driving assessment program developed in response to clinical concerns about the driving safety of individuals with medical conditions. DriveWise clinicians use evidence-based, functional assessments to determine driving competence. In addition, the program was designed to meet the emotional needs of individuals whose driving safety has been called into question. To date, approximately 380 participants have been assessed through DriveWise. The following report details the DriveWise mission, DriveWise team members, and road test results. We continue to refine the assessment process to promote safety and support the dignity and independence of all participants. The DriveWise interdisciplinary approach to practice is a concrete example of how gerontological education across professions can have direct benefits to the older adult.
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Numerical Modeling of an Integrated Vehicle Fluids System Loop for Pressurizing a Cryogenic Tank
NASA Technical Reports Server (NTRS)
LeClair, A. C.; Hedayat, A.; Majumdar, A. K.
2017-01-01
This paper presents a numerical model of the pressurization loop of the Integrated Vehicle Fluids (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance to reduce system weight and enhance reliability, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) conducted tests to verify the functioning of the IVF system using a flight-like tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to support the test program. This paper presents the simulation of three different test series, comparison of numerical prediction and test data and a novel method of presenting data in a dimensionless form. The paper also presents a methodology of implementing a compressor map in a system level code.
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Run-time parallelization and scheduling of loops
NASA Technical Reports Server (NTRS)
Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay
1990-01-01
Run time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases, where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run time, wave fronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run time reordering of loop indices can have a significant impact on performance. Furthermore, the overheads associated with this type of reordering are amortized when the loop is executed several times with the same dependency structure.
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Coronal Loops: Observations and Modeling of Confined Plasma.
Reale, Fabio
Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered and, therefore, topics such as loop oscillations and flaring loops (except for non-solar ones, which provide information on stellar loops) are not specifically addressed here. The observational section discusses the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. More specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC) and impulsive (DC) heating. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.
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On higher order discrete phase-locked loops.
NASA Technical Reports Server (NTRS)
Gill, G. S.; Gupta, S. C.
1972-01-01
An exact mathematical model is developed for a discrete loop of a general order particularly suitable for digital computation. The deterministic response of the loop to the phase step and the frequency step is investigated. The design of the digital filter for the second-order loop is considered. Use is made of the incremental phase plane to study the phase error behavior of the loop. The model of the noisy loop is derived and the optimization of the loop filter for minimum mean-square error is considered.
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Stephens, A N; Hill, T; Sullman, M J M
2016-03-01
Trait driving anger is often, but not always, found to predict both the intensity of anger while driving and subsequent crash-related behaviours. However, a number of studies have not found support for a direct relationship between one's tendency to become angry and anger reported while driving, suggesting that other factors may mediate this relationship. The present self-report study investigated whether, in anger provoking driving situations, the appraisals made by drivers influence the relationship between trait and state anger. A sample of 339 drivers from Ukraine completed the 33-item version of the Driver Anger Scale (DAS; Deffenbacher et al., 1994) and eight questions about their most recent experience of driving anger. A structural equation model found that the intensity of anger experienced was predicted by the negative evaluations of the situation, which was in turn predicted by trait driving anger. However, trait driving anger itself did not predict anger intensity; supporting the hypothesis that evaluations of the driving situation mediate the relationship between trait and state anger. Further, the unique structure of the DAS required to fit the data from the Ukrainian sample, may indicate that the anger inducing situations in Ukraine are different to those of a more developed country. Future research is needed to investigate driving anger in Ukraine in a broader sample and also to confirm the role of the appraisal process in the development of driving anger in both developed and undeveloped countries. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Patel, Malhar P; Schettini, Priscille; O'Leary, Colin P; Bosworth, Hayden B; Anderson, John B; Shah, Kevin P
2018-05-01
Ideally, a referral from a primary care physician (PCP) to a specialist results in a completed specialty appointment with results available to the PCP. This is defined as "closing the referral loop." As health systems grow more complex, regulatory bodies increase vigilance, and reimbursement shifts towards value, closing the referral loop becomes a patient safety, regulatory, and financial imperative. To assess the ability of a large health system to close the referral loop, we used electronic medical record (EMR)-generated data to analyze referrals from a large primary care network to 20 high-volume specialties between July 1, 2015 and June 30, 2016. The primary metric was documented specialist appointment completion rate. Explanatory analyses included documented appointment scheduling rate, individual clinic differences, appointment wait times, and geographic distance to appointments. Of the 103,737 analyzed referral scheduling attempts, only 36,072 (34.8%) resulted in documented complete appointments. Low documented appointment scheduling rates (38.9% of scheduling attempts lacked appointment dates), individual clinic differences in closing the referral loop, and significant differences in wait times and distances to specialists between complete and incomplete appointments drove this gap. Other notable findings include high variation in wait times among specialties and correlation between high wait times and low documented appointment completion rates. The rate of closing the referral loop in this health system is low. Low appointment scheduling rates, individual clinic differences, and patient access issues of wait times and geographic proximity explain much of the gap. This problem is likely common among large health systems with complex provider networks and referral scheduling. Strategies that improve scheduling, decrease variation among clinics, and improve patient access will likely improve rates of closing the referral loop. More research is necessary to
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2017-03-16
When an active region rotated over to the edge of the sun, it presented us with a nice profile view of its elongated loops stretching and swaying above it (Mar. 8-9, 2017). These loops are actually charged particles (made visible in extreme ultraviolet light) swirling along the magnetic field lines of the active region. The video covers about 30 hours of activity. Also of note is a darker twisting mass of plasma to the left of the active region being pulled and spun about by magnetic forces. Video is available at http://photojournal.jpl.nasa.gov/catalog/PIA21562
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Run-time parallelization and scheduling of loops
NASA Technical Reports Server (NTRS)
Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay
1991-01-01
Run-time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run-time, wavefronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing, and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run-time reordering of loop indexes can have a significant impact on performance.
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Hyperstaticity and loops in frictional granular packings
NASA Astrophysics Data System (ADS)
Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.
2009-06-01
The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.
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Loop Heat Pipe Startup Behaviors
NASA Technical Reports Server (NTRS)
Ku, Jentung
2016-01-01
A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.
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High Curie temperature drive layer materials for ion-implanted magnetic bubble devices
NASA Technical Reports Server (NTRS)
Fratello, V. J.; Wolfe, R.; Blank, S. L.; Nelson, T. J.
1984-01-01
Ion implantation of bubble garnets can lower the Curie temperature by 70 C or more, thus limiting high temperature operation of devices with ion-implanted propagation patterns. Therefore, double-layer materials were made with a conventional 2-micron bubble storage layer capped by an ion-implantable drive layer of high Curie temperature, high magnetostriction material. Contiguous disk test patterns were implanted with varying doses of a typical triple implant. Quality of propagation was judged by quasistatic tests on 8-micron period major and minor loops. Variations of magnetization, uniaxial anisotropy, implant dose, and magnetostriction were investigated to ensure optimum flux matching, good charged wall coupling, and wide operating margins. The most successful drive layer compositions were in the systems (SmDyLuCa)3(FeSi)5O12 and (BiGdTmCa)3(FeSi)5O12 and had Curie temperatures 25-44 C higher than the storage layers.
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NASA Technical Reports Server (NTRS)
Cliff, R. A. (Inventor)
1975-01-01
An digital phase-locked loop is provided for deriving a loop output signal from an accumulator output terminal. A phase detecting exclusive OR gate is fed by the loop digital input and output signals. The output of the phase detector is a bi-level digital signal having a duty cycle indicative of the relative phase of the input and output signals. The accumulator is incremented at a first rate in response to a first output level of the phase detector and at a second rate in response to a second output level of the phase detector.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
REN, GANG; LIU, JINXIN; LI, HONGCHANG
A closed-loop proportional-integral (PI) control software is provided for fully mechanically controlled automated electron microscopic tomography. The software is developed based on Gatan DigitalMicrograph, and is compatible with Zeiss LIBRA 120 transmission electron microscope. However, it can be expanded to other TEM instrument with modification. The software consists of a graphical user interface, a digital PI controller, an image analyzing unit, and other drive units (i.e.: image acquire unit and goniometer drive unit). During a tomography data collection process, the image analyzing unit analyzes both the accumulated shift and defocus value of the latest acquired image, and provides the resultsmore » to the digital PI controller. The digital PI control compares the results with the preset values and determines the optimum adjustments of the goniometer. The goniometer drive unit adjusts the spatial position of the specimen according to the instructions given by the digital PI controller for the next tilt angle and image acquisition. The goniometer drive unit achieves high precision positioning by using a backlash elimination method. The major benefits of the software are: 1) the goniometer drive unit keeps pre-aligned/optimized beam conditions unchanged and achieves position tracking solely through mechanical control; 2) the image analyzing unit relies on only historical data and therefore does not require additional images/exposures; 3) the PI controller enables the system to dynamically track the imaging target with extremely low system error.« less
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Driving simulation for evaluation and rehabilitation of driving after stroke.
Akinwuntan, Abiodun Emmanuel; Wachtel, Jerry; Rosen, Peter Newman
2012-08-01
Driving is an important activity of daily living. Loss of driving privileges can lead to depression, decreased access to medical care, and increased healthcare costs. The ability to drive is often affected after stroke. In approximately 30% of stroke survivors, it is clear from the onset that driving will no longer be possible. Approximately 33% of survivors will be able to return to driving with little or no retraining, and 35% will require driving-related rehabilitation before they can resume safe driving again. The ability to drive is not routinely evaluated after stroke, and there is no established rehabilitation program for poststroke driving. When driving evaluation does occur, it is not always clear which tests are the most salient for accurately assessing poststroke driving ability. Investigators have examined the efficacy of various methodologies to predict driving performance after stroke and have found mixed results, with each method having unique weaknesses, including poor predictive ability, poor face validity, poor sensitivity or specificity, and limited reliability. Here we review common models of driving to gain insight into why single-construct visual or cognitive off-road measures are inadequate for evaluating driving, a complex and dynamic activity that involves timely interaction of multiple motor, visual, cognitive, and perceptual skills. We also examine the potential for driving simulators to overcome the problems currently faced in the evaluation and rehabilitation of driving after stroke. Finally, we offer suggestions for the future direction of simulator-based poststroke driving evaluation and training. Copyright © 2012 National Stroke Association. Published by Elsevier Inc. All rights reserved.
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Method of implementing digital phase-locked loops
NASA Technical Reports Server (NTRS)
Stephens, Scott A. (Inventor); Thomas, Jess Brooks, Jr. (Inventor)
1993-01-01
In a new formulation for digital phase-locked loops, loop-filter constants are determined from loop roots that can each be selectively placed in the s-plane on the basis of a new set of parameters, each with simple and direct physical meaning in terms of loop noise bandwidth, root-specific decay rate, or root-specific damping. Loops of first to fourth order are treated in the continuous-update approximation (BLT yields 0) and in a discrete-update formulation with arbitrary BLT. Deficiencies of the continuous-update approximation in large-BLT applications are avoided in the new discrete-update formulation. A new method for direct, transient-free acquisition with third- and fourth-order loops can improve the versatility and reliability of acquisition with such loops.
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Closed-Loop Targeted Memory Reactivation during Sleep Improves Spatial Navigation.
Shimizu, Renee E; Connolly, Patrick M; Cellini, Nicola; Armstrong, Diana M; Hernandez, Lexus T; Estrada, Rolando; Aguilar, Mario; Weisend, Michael P; Mednick, Sara C; Simons, Stephen B
2018-01-01
Sounds associated with newly learned information that are replayed during non-rapid eye movement (NREM) sleep can improve recall in simple tasks. The mechanism for this improvement is presumed to be reactivation of the newly learned memory during sleep when consolidation takes place. We have developed an EEG-based closed-loop system to precisely deliver sensory stimulation at the time of down-state to up-state transitions during NREM sleep. Here, we demonstrate that applying this technology to participants performing a realistic navigation task in virtual reality results in a significant improvement in navigation efficiency after sleep that is accompanied by increases in the spectral power especially in the fast (12-15 Hz) sleep spindle band. Our results show promise for the application of sleep-based interventions to drive improvement in real-world tasks.
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Palkowski, Marek; Bielecki, Wlodzimierz
2017-06-02
RNA secondary structure prediction is a compute intensive task that lies at the core of several search algorithms in bioinformatics. Fortunately, the RNA folding approaches, such as the Nussinov base pair maximization, involve mathematical operations over affine control loops whose iteration space can be represented by the polyhedral model. Polyhedral compilation techniques have proven to be a powerful tool for optimization of dense array codes. However, classical affine loop nest transformations used with these techniques do not optimize effectively codes of dynamic programming of RNA structure predictions. The purpose of this paper is to present a novel approach allowing for generation of a parallel tiled Nussinov RNA loop nest exposing significantly higher performance than that of known related code. This effect is achieved due to improving code locality and calculation parallelization. In order to improve code locality, we apply our previously published technique of automatic loop nest tiling to all the three loops of the Nussinov loop nest. This approach first forms original rectangular 3D tiles and then corrects them to establish their validity by means of applying the transitive closure of a dependence graph. To produce parallel code, we apply the loop skewing technique to a tiled Nussinov loop nest. The technique is implemented as a part of the publicly available polyhedral source-to-source TRACO compiler. Generated code was run on modern Intel multi-core processors and coprocessors. We present the speed-up factor of generated Nussinov RNA parallel code and demonstrate that it is considerably faster than related codes in which only the two outer loops of the Nussinov loop nest are tiled.
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Observations of loops and prominences
NASA Technical Reports Server (NTRS)
Strong, Keith T.
1994-01-01
We review recent observations by the Yohkoh-SXT (Soft X-ray Telescope) in collaboration with other spacecraft and ground-based observatories of coronal loops and prominences. These new results point to problems that SoHO will be able to address. With a unique combination of rapid-cadence digital imaging (greater than or equal to 32 s full-disk and greater than or equal to 2 s partial-frame images), high spatial resolution (greater than or equal to 2.5 arcsec pixels), high sensitivity (EM less than or equal to 10(exp 42) cm(exp -3)), a low-scatter mirror, and large dynamic range, SXT can observe a vast range of targets on the Sun. Over the first 21 months of Yohkoh operations SXT has taken over one million images of the corona and so is building up an invaluable long-term database on the large-scale corona and loop geometry. The most striking thing about the SXT images is the range of loop sizes and shapes. The active regions are a bright tangle of magnetic field lines, surrounded by a network of large-scale quiet-Sun loops stretching over distances in excess of 105 km. The cross-section of most loops seems to be constant. Loops displaying significant Gamma's are the exception, not the rule, implying the presence of widespread currents in the corona. All magnetic structures show changes. Time scales range from seconds to months. The question of how these structures are formed, become filled with hot plasma, and are maintained is still open. While we see the propagation of brightenings along the length of active-region loops and in X-ray jets with velocities of several hundred km/s, much higher velocities are seen in the quiet Sun. In XBP flares, for example, velocities of over 1000 km/s are common. Active-region loops seem to be in constant motion, moving slowly outward, carrying plasma with them. During flares, loops often produce localized brightenings at the base and later at the apex of the loop. Quiescent filaments and prominences have been observed regularly
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Decay-less kink oscillations in coronal loops
NASA Astrophysics Data System (ADS)
Anfinogentov, S.; Nisticò, G.; Nakariakov, V. M.
2013-12-01
Context. Kink oscillations of coronal loops in an off-limb active region are detected with the Imaging Assembly Array (AIA) instruments of the Solar Dynamics Observatory (SDO) at 171 Å. Aims: We aim to measure periods and amplitudes of kink oscillations of different loops and to determinate the evolution of the oscillation phase along the oscillating loop. Methods: Oscillating coronal loops were visually identified in the field of view of SDO/AIA and STEREO/EUVI-A: the loop length was derived by three-dimensional analysis. Several slits were taken along the loops to assemble time-distance maps. We identified oscillatory patterns and retrieved periods and amplitudes of the oscillations. We applied the cross-correlation technique to estimate the phase shift between oscillations at different segments of oscillating loops. Results: We found that all analysed loops show low-amplitude undamped transverse oscillations. Oscillation periods of loops in the same active region range from 2.5 to 11 min, and are different for different loops. The displacement amplitude is lower than 1 Mm. The oscillation phase is constant along each analysed loop. The spatial structure of the phase of the oscillations corresponds to the fundamental standing kink mode. We conclude that the observed behaviour is consistent with the empirical model in terms of a damped harmonic resonator affected by a non-resonant continuously operating external force. A movie is available in electronic form at http://www.aanda.org
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... texting Having a medical condition which affects your driving For your safety and the safety of others, do not drive while impaired. Have someone else drive you or take public transportation when you cannot drive. If you need to take a call or send a text ...
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NASA Astrophysics Data System (ADS)
Lan, Ganhui
2015-09-01
We present here the analytical relation between the gain of eukaryotic gradient sensing network and the associated thermodynamic cost. By analyzing a general incoherent type-1 feed-forward loop, we derive the gain function (G ) through the reaction network and explicitly show that G depends on the nonequilibrium factor (0 ≤γ ≤1 with γ =0 and 1 representing irreversible and equilibrium reaction systems, respectively), the Michaelis constant (KM), and the turnover ratio (rcat) of the participating enzymes. We further find the maximum possible gain is intrinsically determined by KM/Gmax=(1 /KM+2 ) /4 . Our model also indicates that the dissipated energy (measured by -lnγ ), from the intracellular energy-bearing bioparticles (e.g., ATP), is used to generate a force field Fγ∝(1 -√{γ }) that reshapes and disables the effective potential around the zero gain region, which leads to the ultrasensitive response to external chemical gradients.
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Improving Drive Files for Vehicle Road Simulations
NASA Astrophysics Data System (ADS)
Cherng, John G.; Goktan, Ali; French, Mark; Gu, Yi; Jacob, Anil
2001-09-01
Shaker tables are commonly used in laboratories for automotive vehicle component testing to study durability and acoustics performance. An example is development testing of car seats. However, it is difficult to repeat the measured road data perfectly with the response of a shaker table as there are basic differences in dynamic characteristics between a flexible vehicle and substantially rigid shaker table. In addition, there are performance limits in the shaker table drive systems that can limit correlation. In practice, an optimal drive signal for the actuators is created iteratively. During each iteration, the error between the road data and the response data is minimised by an optimising algorithm which is generally a part of the feed back loop of the shake table controller. This study presents a systematic investigation to the errors in time and frequency domains as well as joint time-frequency domain and an evaluation of different digital signal processing techniques that have been used in previous work. In addition, we present an innovative approach that integrates the dynamic characteristics of car seats and the human body into the error-minimising iteration process. We found that the iteration process can be shortened and the error reduced by using a weighting function created by normalising the frequency response function of the car seat. Two road data test sets were used in the study.
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A qualitative exploration of driving stress and driving discourtesy.
Scott-Parker, B; Jones, C M; Rune, K; Tucker, J
2018-05-31
Driving courtesy, and conversely driving discourtesy, recently has been of great interest in the public domain. In addition, there has been increasing recognition of the negative impact of stress upon the individual's health and wellbeing, with a plethora of interventions aimed at minimising stress more generally. The research literature regarding driving dis/courtesy, in comparison, is scant, with a handful of studies examining the dis/courteous driving behaviour of road users, and the relationship between driving discourtesy and driving stress. To examine courteous and discourteous driving experiences, and to explore the impact of stress associated with such driving experiences. Thirty-eight drivers (20 females) from the Sunshine Coast region volunteered to participate in one of four 1-1.5 h focus groups. Content analysis used the verbatim utterances captured via an Mp3 device. Three themes pertaining to stressful and discourteous interactions were identified. Theme one pertained to the driving context: road infrastructure (eg, roundabouts, roadwork), vehicles (eg, features), location (eg, country vs city, unfamiliar areas), and temporal aspects (eg, holidays). Theme two pertained to other road users: their behaviour (eg, tailgating, merging), and unknown factors (eg, illicit and licit drug use). Theme three pertained to the self as road user: their own behaviours (eg, deliberate intimidation), and their emotions (eg, angry reaction to other drivers, being in control). Driving dis/courtesy and driving stress is a complex phenomenon, suggesting complex intervention efforts are required. Driving discourtesy was reported as being highly stressful, therefore intervention efforts which encourage driving courtesy and which foster emotional capacity to cope with stressful circumstances appear warranted. Copyright © 2018. Published by Elsevier Ltd.
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Precision increase in electric drive speed loop of robotic complexes and process lines
NASA Astrophysics Data System (ADS)
Tulegenov, E.; Imanova, A. A.; Platonov, V. V.
2018-05-01
The article presents the principles of synthesis of control structures for highprecision electric drives of robotic complexes and manipulators. It has been theoretically shown and experimentally confirmed that improved characteristics of speed maintenance in the zone of significant overloads are achieved in systems of series excitation. They are achieved due to the redistribution of control signals both in the zone of setting the armature current and in the excitation currents. At the same time, the characteristic of the electromagnetic torque becomes linear because the demagnetizing effect of the armature response is compensated by the setting of the excitation current. It is recommended in those cases when it is necessary to extend the range of speed control with a significant reduction in load to apply structures with two-zone speed control. The regulation of the weakening of the excitation flow is more convenient as a function of the voltage in the armature windings.
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Near optimum digital phase locked loops.
NASA Technical Reports Server (NTRS)
Polk, D. R.; Gupta, S. C.
1972-01-01
Near optimum digital phase locked loops are derived utilizing nonlinear estimation theory. Nonlinear approximations are employed to yield realizable loop structures. Baseband equivalent loop gains are derived which under high signal to noise ratio conditions may be calculated off-line. Additional simplifications are made which permit the application of the Kalman filter algorithms to determine the optimum loop filter. Performance is evaluated by a theoretical analysis and by simulation. Theoretical and simulated results are discussed and a comparison to analog results is made.
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Filter for third order phase locked loops
NASA Technical Reports Server (NTRS)
Crow, R. B.; Tausworthe, R. C. (Inventor)
1973-01-01
Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided.
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Wilson loop from a Dyson equation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pak, M.; Reinhardt, H.
2009-12-15
The Dyson equation proposed for planar temporal Wilson loops in the context of supersymmetric gauge theories is critically analyzed thereby exhibiting its ingredients and approximations involved. We reveal its limitations and identify its range of applicability in nonsupersymmetric gauge theories. In particular, we show that this equation is applicable only to strongly asymmetric planar Wilson loops (consisting of a long and a short pair of loop segments) and as a consequence the Wilsonian potential can be extracted only up to intermediate distances. By this equation the Wilson loop is exclusively determined by the gluon propagator. We solve the Dyson equationmore » in Coulomb gauge for the temporal Wilson loop with the instantaneous part of the gluon propagator and for the spatial Wilson loop with the static gluon propagator obtained in the Hamiltonian approach to continuum Yang-Mills theory and on the lattice. In both cases we find a linearly rising color potential.« less
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Closed loop computer control for an automatic transmission
Patil, Prabhakar B.
1989-01-01
In an automotive vehicle having an automatic transmission that driveably connects a power source to the driving wheels, a method to control the application of hydraulic pressure to a clutch, whose engagement produces an upshift and whose disengagement produces a downshift, the speed of the power source, and the output torque of the transmission. The transmission output shaft torque and the power source speed are the controlled variables. The commanded power source torque and commanded hydraulic pressure supplied to the clutch are the control variables. A mathematical model is formulated that describes the kinematics and dynamics of the powertrain before, during and after a gear shift. The model represents the operating characteristics of each component and the structural arrangement of the components within the transmission being controlled. Next, a close loop feedback control is developed to determine the proper control law or compensation strategy to achieve an acceptably smooth gear ratio change, one in which the output torque disturbance is kept to a minimum and the duration of the shift is minimized. Then a computer algorithm simulating the shift dynamics employing the mathematical model is used to study the effects of changes in the values of the parameters established from a closed loop control of the clutch hydraulic and the power source torque on the shift quality. This computer simulation is used also to establish possible shift control strategies. The shift strategies determined from the prior step are reduced to an algorithm executed by a computer to control the operation of the power source and the transmission.
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Numerical magnetohydrodynamic simulations of expanding flux ropes: Influence of boundary driving
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tacke, Thomas; Dreher, Jürgen; Sydora, Richard D.
2013-07-15
The expansion dynamics of a magnetized, current-carrying plasma arch is studied by means of time-dependent ideal MHD simulations. Initial conditions model the setup used in recent laboratory experiments that in turn simulate coronal loops [J. Tenfelde et al., Phys. Plasmas 19, 072513 (2012); E. V. Stenson and P. M. Bellan, Plasma Phys. Controlled Fusion 54, 124017 (2012)]. Boundary conditions of the electric field at the “lower” boundary, intersected by the arch, are chosen such that poloidal magnetic flux is injected into the domain, either localized at the arch footpoints themselves or halfway between them. These conditions are motivated by themore » tangential electric field expected to exist in the laboratory experiments due to the external circuit that drives the plasma current. The boundary driving is found to systematically enhance the expansion velocity of the plasma arch. While perturbations at the arch footpoints also deform its legs and create characteristic elongated segments, a perturbation between the footpoints tends to push the entire structure upwards, retaining an ellipsoidal shape.« less
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DNA looping by FokI: the impact of twisting and bending rigidity on protein-induced looping dynamics
Laurens, Niels; Rusling, David A.; Pernstich, Christian; Brouwer, Ineke; Halford, Stephen E.; Wuite, Gijs J. L.
2012-01-01
Protein-induced DNA looping is crucial for many genetic processes such as transcription, gene regulation and DNA replication. Here, we use tethered-particle motion to examine the impact of DNA bending and twisting rigidity on loop capture and release, using the restriction endonuclease FokI as a test system. To cleave DNA efficiently, FokI bridges two copies of an asymmetric sequence, invariably aligning the sites in parallel. On account of the fixed alignment, the topology of the DNA loop is set by the orientation of the sites along the DNA. We show that both the separation of the FokI sites and their orientation, altering, respectively, the twisting and the bending of the DNA needed to juxtapose the sites, have profound effects on the dynamics of the looping interaction. Surprisingly, the presence of a nick within the loop does not affect the observed rigidity of the DNA. In contrast, the introduction of a 4-nt gap fully relaxes all of the torque present in the system but does not necessarily enhance loop stability. FokI therefore employs torque to stabilise its DNA-looping interaction by acting as a ‘torsional’ catch bond. PMID:22373924
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Holokinetic drive: centromere drive in chromosomes without centromeres.
Bureš, Petr; Zedek, František
2014-08-01
Similar to how the model of centromere drive explains the size and complexity of centromeres in monocentrics (organisms with localized centromeres), our model of holokinetic drive is consistent with the divergent evolution of chromosomal size and number in holocentrics (organisms with nonlocalized centromeres) exhibiting holokinetic meiosis (holokinetics). Holokinetic drive is proposed to facilitate chromosomal fission and/or repetitive DNA removal (or any segmental deletion) when smaller homologous chromosomes are preferentially inherited or chromosomal fusion and/or repetitive DNA proliferation (or any segmental duplication) when larger homologs are preferred. The hypothesis of holokinetic drive is supported primarily by the negative correlation between chromosome number and genome size that is documented in holokinetic lineages. The supporting value of two older cross-experiments on holokinetic structural heterozygotes (the rush Luzula elegans and butterflies of the genus Antheraea) that indicate the presence of size-preferential homolog transmission via female meiosis for holokinetic drive is discussed, along with the further potential consequences of holokinetic drive in comparison with centromere drive. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.
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An Excitatory Loop with Astrocytes Contributes to Drive Neurons to Seizure Threshold
Chiavegato, Angela; Zonta, Micaela; Cammarota, Mario; Brondi, Marco; Vetri, Francesco; Uva, Laura; Pozzan, Tullio; de Curtis, Marco; Ratto, Gian Michele; Carmignoto, Giorgio
2010-01-01
Seizures in focal epilepsies are sustained by a highly synchronous neuronal discharge that arises at restricted brain sites and subsequently spreads to large portions of the brain. Despite intense experimental research in this field, the earlier cellular events that initiate and sustain a focal seizure are still not well defined. Their identification is central to understand the pathophysiology of focal epilepsies and to develop new pharmacological therapies for drug-resistant forms of epilepsy. The prominent involvement of astrocytes in ictogenesis was recently proposed. We test here whether a cooperation between astrocytes and neurons is a prerequisite to support ictal (seizure-like) and interictal epileptiform events. Simultaneous patch-clamp recording and Ca2+ imaging techniques were performed in a new in vitro model of focal seizures induced by local applications of N-methyl-D-aspartic acid (NMDA) in rat entorhinal cortex slices. We found that a Ca2+ elevation in astrocytes correlates with both the initial development and the maintenance of a focal, seizure-like discharge. A delayed astrocyte activation during ictal discharges was also observed in other models (including the whole in vitro isolated guinea pig brain) in which the site of generation of seizure activity cannot be precisely monitored. In contrast, interictal discharges were not associated with Ca2+ changes in astrocytes. Selective inhibition or stimulation of astrocyte Ca2+ signalling blocked or enhanced, respectively, ictal discharges, but did not affect interictal discharge generation. Our data reveal that neurons engage astrocytes in a recurrent excitatory loop (possibly involving gliotransmission) that promotes seizure ignition and sustains the ictal discharge. This neuron–astrocyte interaction may represent a novel target to develop effective therapeutic strategies to control seizures. PMID:20405049
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Cochran, C.B.
This patent describes a double nut setting tool and liner hanger assembly. It comprises a tool which is releasably coupled to the liner hanger by a nut means threadedly connected to the liner hanger: upon reaching a desired setting location, hanging the liner hanger in the well to support the weight of the liner and to permit rotation of the liner: manipulating the string of pipe to simultaneously rotate the nut means to a released condition relative to the liner hanger while rotating a lock nut in a clutch housing into a locking position in the clutch housing to engagemore » the clutch housing with the liner; and applying weight to the string of pipe to engage the clutch housing with the liner when the coupling nut is released and the lock nut is in a locking position so that the liner can be rotated by rotation of the string of pipe after the coupling nut is released.« less
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Tritium Management Loop Design Status
DOE Office of Scientific and Technical Information (OSTI.GOV)
Rader, Jordan D.; Felde, David K.; McFarlane, Joanna
This report summarizes physical, chemical, and engineering analyses that have been done to support the development of a test loop to study tritium migration in 2LiF-BeF2 salts. The loop will operate under turbulent flow and a schematic of the apparatus has been used to develop a model in Mathcad to suggest flow parameters that should be targeted in loop operation. The introduction of tritium into the loop has been discussed as well as various means to capture or divert the tritium from egress through a test assembly. Permeation was calculated starting with a Modelica model for a transport through amore » nickel window into a vacuum, and modifying it for a FLiBe system with an argon sweep gas on the downstream side of the permeation interface. Results suggest that tritium removal with a simple tubular permeation device will occur readily. Although this system is idealized, it suggests that rapid measurement capability in the loop may be necessary to study and understand tritium removal from the system.« less
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Driving Anger and Driving Behavior in Adults with ADHD
ERIC Educational Resources Information Center
Richards, Tracy L.; Deffenbacher, Jerry L.; Rosen, Lee A.; Barkley, Russell A.; Rodricks, Trisha
2006-01-01
Objective: This study assesses whether anger in the context of driving is associated with the negative driving outcomes experienced by individuals with ADHD. Method: ADHD adults (n = 56) complete measures of driving anger, driving anger expression, angry thoughts behind the wheel, and aggressive, risky, and crash-related behavior. Results are…
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Polyakov loop modeling for hot QCD
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fukushima, Kenji; Skokov, Vladimir
Here, we review theoretical aspects of quantum chromodynamics (QCD) at finite temperature. The most important physical variable to characterize hot QCD is the Polyakov loop, which is an approximate order parameter for quark deconfinement in a hot gluonic medium. Additionally to its role as an order parameter, the Polyakov loop has rich physical contents in both perturbative and non-perturbative sectors. This review covers a wide range of subjects associated with the Polyakov loop from topological defects in hot QCD to model building with coupling to the Polyakov loop.
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Capillary-Condenser-Pumped Heat-Transfer Loop
NASA Technical Reports Server (NTRS)
Silverstein, Calvin C.
1989-01-01
Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.
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Polyakov loop modeling for hot QCD
Fukushima, Kenji; Skokov, Vladimir
2017-06-19
Here, we review theoretical aspects of quantum chromodynamics (QCD) at finite temperature. The most important physical variable to characterize hot QCD is the Polyakov loop, which is an approximate order parameter for quark deconfinement in a hot gluonic medium. Additionally to its role as an order parameter, the Polyakov loop has rich physical contents in both perturbative and non-perturbative sectors. This review covers a wide range of subjects associated with the Polyakov loop from topological defects in hot QCD to model building with coupling to the Polyakov loop.
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Kalman Orbit Optimized Loop Tracking
NASA Technical Reports Server (NTRS)
Young, Lawrence E.; Meehan, Thomas K.
2011-01-01
Under certain conditions of low signal power and/or high noise, there is insufficient signal to noise ratio (SNR) to close tracking loops with individual signals on orbiting Global Navigation Satellite System (GNSS) receivers. In addition, the processing power available from flight computers is not great enough to implement a conventional ultra-tight coupling tracking loop. This work provides a method to track GNSS signals at very low SNR without the penalty of requiring very high processor throughput to calculate the loop parameters. The Kalman Orbit-Optimized Loop (KOOL) tracking approach constitutes a filter with a dynamic model and using the aggregate of information from all tracked GNSS signals to close the tracking loop for each signal. For applications where there is not a good dynamic model, such as very low orbits where atmospheric drag models may not be adequate to achieve the required accuracy, aiding from an IMU (inertial measurement unit) or other sensor will be added. The KOOL approach is based on research JPL has done to allow signal recovery from weak and scintillating signals observed during the use of GPS signals for limb sounding of the Earth s atmosphere. That approach uses the onboard PVT (position, velocity, time) solution to generate predictions for the range, range rate, and acceleration of the low-SNR signal. The low- SNR signal data are captured by a directed open loop. KOOL builds on the previous open loop tracking by including feedback and observable generation from the weak-signal channels so that the MSR receiver will continue to track and provide PVT, range, and Doppler data, even when all channels have low SNR.
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Indirect rotor position sensing in real time for brushless permanent magnet motor drives
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ertugrul, N.; Acarnley, P.P.
1998-07-01
This paper describes a modern solution to real-time rotor position estimation of brushless permanent magnet (PM) motor drives. The position estimation scheme, based on flux linkage and line-current estimation, is implemented in real time by using the abc reference frame, and it is tested dynamically. The position estimation model of the test motor, development of hardware, and basic operation of the digital signal processor (DSP) are discussed. The overall position estimation strategy is accomplished with a fast DSP (TMS320C30). The method is a shaft position sensorless method that is applicable to a wide range of excitation types in brushless PMmore » motors without any restriction on the motor model and the current excitation. Both rectangular and sinewave-excited brushless PM motor drives are examined, and the results are given to demonstrate the effectiveness of the method with dynamic loads in closed estimated position loop.« less
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Motorized CPM/CAM physiotherapy device with sliding-mode Fuzzy Neural Network control loop.
Ho, Hung-Jung; Chen, Tien-Chi
2009-11-01
Continuous passive motion (CPM) and controllable active motion (CAM) physiotherapy devices promote rehabilitation of damaged joints. This paper presents a computerized CPM/CAM system that obviates the need for mechanical resistance devices such as springs. The system is controlled by a computer which performs sliding-mode Fuzzy Neural Network (FNN) calculations online. CAM-type resistance force is generated by the active performance of an electric motor which is controlled so as to oppose the motion of the patient's leg. A force sensor under the patient's foot on the device pedal provides data for feedback in a sliding-mode FNN control loop built around the motor. Via an active impedance control feedback system, the controller drives the motor to behave similarly to a damped spring by generating and controlling the amplitude and direction of the pedal force in relation to the patient's leg. Experiments demonstrate the high sensitivity and speed of the device. The PC-based feedback nature of the control loop means that sophisticated auto-adaptable CPM/CAM custom-designed physiotherapy becomes possible. The computer base also allows extensive data recording, data analysis and network-connected remote patient monitoring.
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Advanced ECCD based NTM control in closed-loop operation at ASDEX Upgrade (AUG)
NASA Astrophysics Data System (ADS)
Reich, Matthias; Barrera-Orte, Laura; Behler, Karl; Bock, Alexander; Giannone, Louis; Maraschek, Marc; Poli, Emanuele; Rapson, Chris; Stober, Jörg; Treutterer, Wolfgang
2012-10-01
In high performance plasmas, Neoclassical Tearing Modes (NTMs) are regularly observed at reactor-grade beta-values. They limit the achievable normalized beta, which is undesirable because fusion performance scales as beta squared. The method of choice for controlling and avoiding NTMs at AUG is the deposition of ECCD inside the magnetic island for stabilization in real-time (rt). Our approach to tackling such complex control problems using real-time diagnostics allows rigorous optimization of all subsystems. Recent progress in rt-equilibrium reconstruction (< 3.5 ms), rt-localization of NTMs (< 8 ms) and rt beam tracing (< 25 ms) allows closed-loop feedback operation using multiple movable mirrors as the ECCD deposition actuator. The rt-equilibrium uses function parametrization or a fast Grad-Shafranov solver with an option to include rt-MSE measurements. The island localization is based on a correlation of ECE and filtered Mirnov signals. The rt beam-tracing module provides deposition locations and their derivative versus actuator position of multiple gyrotrons. The ``MHD controller'' finally drives the actuators. Results utilizing closed-loop operation with multiple gyrotrons and their effect on NTMs are shown.
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Parallel Digital Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Sadr, Ramin; Shah, Biren N.; Hinedi, Sami M.
1995-01-01
Wide-band microwave receivers of proposed type include digital phase-locked loops in which band-pass filtering and down-conversion of input signals implemented by banks of multirate digital filters operating in parallel. Called "parallel digital phase-locked loops" to distinguish them from other digital phase-locked loops. Systems conceived as cost-effective solution to problem of filtering signals at high sampling rates needed to accommodate wide input frequency bands. Each of M filters process 1/M of spectrum of signal.
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Meng, Annette; Siren, Anu
2012-11-01
Ageing in general is associated with functional decline that may have an adverse effect on driving. Nevertheless, older drivers have been found to show good judgement and to self-regulate their driving, which may enable them to continue driving safely despite functional decline. The process of the self-monitoring of driving ability and the awareness of functional decline, and its association with the self-regulation of driving is, however, not fully understood. The aim of the present study was to examine the perceived changes in driving skills, the discomfort experienced in driving, and the self-regulation of driving as measured by the avoidance of certain driving situations by older drivers with different levels of self-rated cognitive problems. Eight hundred and forty Danish drivers aged 75-95 completed a structured telephone interview. The results showed that the recognition of cognitive problems was associated with an experience of improvement in higher level driving skills but also of a decline in lower level driving skills. Moreover, cognitive problems recognised by drivers were associated with discomfort in, and avoidance of, driving situations. Finally, a linear relationship between discomfort in driving and avoidance was found and this tended to be stronger for drivers recognising cognitive problems. The results indicate that older drivers who recognise problems with cognitive functions display good self-assessment of changes in their driving skills. In addition, the results suggest that driving-related discomfort is an important factor affecting the self-regulation of driving. Finally, the findings indicate that driving-related discomfort functions as an indirect self-monitoring of driving ability and may contribute to the safe driving performance of Danish older drivers. Copyright © 2012 Elsevier Ltd. All rights reserved.
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State demonstration project : loop detectors.
DOT National Transportation Integrated Search
1985-01-01
The Virginia Department of Highways and Transportation frequently utilizes induction loops in its vehicle detector systems. Although not documented, there have been many instances of loop failure; therefore, the practices and materials used by the De...
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Steady State Model for Solar Coronal Loops
NASA Astrophysics Data System (ADS)
Sugiyama, L.; Asgari-Targhi, M.
2017-12-01
Solar coronal loops on the surface of the sun provide background magnetic and plasma structures for the release of a significant amount of the sun's energy, through energetic solar flares and coronal mass ejections and more gradual processes. Understanding their steady states is the first step in understanding loop dynamics. A consistent MHD steady state model, for a curved magnetic flux rope that contains plasma, has been developed[1] for simple coronal loops with both ends anchored in the photosphere. Plasma pressure or current makes the loop unstable to expansion in major radius and must be balanced by external forces, such as the solar gravity. The MHD momentum equation has a well defined small parameter ordering in the loop inverse aspect ratio ɛ=a/Ro (minor/major radius). Different types of common coronal loops fall in different parameter regimes, determined by the relative values of the plasma beta β=po/(Bo2/2μo), the MHD gravity parameter Ĝ≡ga/vA2 (the gravitational acceleration g normalized to the minor radius a and shear Alfvén velocity vA), and ɛ. The largest possible gravity, Ĝ ɛ1β, corresponds to the largest loops because it reduces the plasma density at the top of the loop exponentially compared to its lower ends, reducing the downward gravitational force -ρĜ there. The thin loops that are ubiquitous in solar active regions have ``high'' beta, β ɛ1, for ɛ≃0.02, and fit the predicted model scalings. The thicker loops that can give rise to flares and CMEs have ``low'' beta, β ɛ2. Cool loops, such as solar filaments outside active regions, that have a central pressure lower than that of the surrounding corona would have the strongest stability against radial expansion. The model raises a number of questions about the connection of loops to the photosphere and the force-free nature of the magnetic field there. [1] L. Sugiyama, M. Asgari-Targhi, Phys. Plasmas 24, 022904 (2017).
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A dynamic flare with anomalously dense flare loops
NASA Technical Reports Server (NTRS)
Svestka, Z.; Fontenla, J. M.; Machado, M. E.; Martin, S. F.; Neidig, D. F.
1986-01-01
The dynamic flare of November 6, 1980 developed a rich system of growing loops which could be followed in H-alpha for 1.5 hours. Throughout the flare, these loops, near the limb, were seen in emission against the disk. Theoretical computations of b-values for a hydrogen atom reveal that this requires electron densities in the loops to be close to 10 to the 12th per cu cm. From measured widths of higher Balmer lines the density at the tops of the loops was found to be 4 x 10 to the 12th per cu cm if no nonthermal motions were present. It is now general knowledge that flare loops are initially observed in X-rays and become visible in H-alpha only after cooling. For such a high density a loop would cool through radiation from 10 to the 7th K to 10 to the 4th K within a few minutes so that the dense H-alpha loops should have heights very close to the heights of the X-ray loops. This, however, contradicts the observations obtained by the HXIS and FCS instruments on board SMM which show the X-ray loops at much higher altitudes than the loops in H-alpha. Therefore, the density must have been significantly smaller when the loops were formed and the flare loops were apparently both shrinking and becoming denser while cooling.
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Automatic blocking of nested loops
NASA Technical Reports Server (NTRS)
Schreiber, Robert; Dongarra, Jack J.
1990-01-01
Blocked algorithms have much better properties of data locality and therefore can be much more efficient than ordinary algorithms when a memory hierarchy is involved. On the other hand, they are very difficult to write and to tune for particular machines. The reorganization is considered of nested loops through the use of known program transformations in order to create blocked algorithms automatically. The program transformations used are strip mining, loop interchange, and a variant of loop skewing in which invertible linear transformations (with integer coordinates) of the loop indices are allowed. Some problems are solved concerning the optimal application of these transformations. It is shown, in a very general setting, how to choose a nearly optimal set of transformed indices. It is then shown, in one particular but rather frequently occurring situation, how to choose an optimal set of block sizes.
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2018-06-11
Giant, bright coronal loops trace out the magnetic field lines above an active region from June 4-6, 2018. The wavelength of extreme ultraviolet light shown here is emitted by ionized iron travelling along the field lines, super-heated to approximately 1 million degrees K. Coronal loops were not seen in this level of detail until the Solar Dynamics Observatory was launched in 2010 and came online, giving solar scientists new data with which to study the Sun and its processes. https://photojournal.jpl.nasa.gov/catalog/PIA22508
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Larsen, T; Doll, J C; Loizeau, F; Hosseini, N; Peng, A W; Fantner, G; Ricci, A J; Pruitt, B L
2017-01-01
Electrothermal actuators have many advantages compared to other actuators used in Micro-Electro-Mechanical Systems (MEMS). They are simple to design, easy to fabricate and provide large displacements at low voltages. Low voltages enable less stringent passivation requirements for operation in liquid. Despite these advantages, thermal actuation is typically limited to a few kHz bandwidth when using step inputs due to its intrinsic thermal time constant. However, the use of pre-shaped input signals offers a route for reducing the rise time of these actuators by orders of magnitude. We started with an electrothermally actuated cantilever having an initial 10-90% rise time of 85 μs in air and 234 μs in water for a standard open-loop step input. We experimentally characterized the linearity and frequency response of the cantilever when operated in air and water, allowing us to obtain transfer functions for the two cases. We used these transfer functions, along with functions describing desired reduced rise-time system responses, to numerically simulate the required input signals. Using these pre-shaped input signals, we improved the open-loop 10-90% rise time from 85 μs to 3 μs in air and from 234 μs to 5 μs in water, an improvement by a factor of 28 and 47, respectively. Using this simple control strategy for MEMS electrothermal actuators makes them an attractive alternative to other high speed micromechanical actuators such as piezoelectric stacks or electrostatic comb structures which are more complex to design, fabricate, or operate.
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The Projectile Inside the Loop
ERIC Educational Resources Information Center
Varieschi, Gabriele U.
2006-01-01
The loop-the-loop demonstration can be easily adapted to study the kinematics of projectile motion, when the moving body falls inside the apparatus. Video capturing software can be used to reveal peculiar geometrical effects of this simple but educational experiment.
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ERIC Educational Resources Information Center
Cetin, Ibrahim
2015-01-01
The purpose of this study is to explore students' understanding of loops and nested loops concepts. Sixty-three mechanical engineering students attending an introductory programming course participated in the study. APOS (Action, Process, Object, Schema) is a constructivist theory developed originally for mathematics education. This study is the…
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Method of Implementing Digital Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Stephens, Scott A. (Inventor); Thomas, J. Brooks (Inventor)
1997-01-01
In a new formulation for digital phase-locked loops, loop-filter constants are determined from loop roots that can each be selectively placed in the s-plane on the basis of a new set of parameters, each with simple and direct physical meaning in terms of loop noise bandwidth, root-specific decay rate, and root-specific damping. Loops of first to fourth order are treated in the continuous-update approximation (B(sub L)T approaches 0) and in a discrete-update formulation with arbitrary B(sub L)T. Deficiencies of the continuous-update approximation in large-B(sub L)T applications are avoided in the new discrete-update formulation.
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Premeasured Chordal Loops for Mitral Valve Repair.
Gillinov, Marc; Quinn, Reed; Kerendi, Faraz; Gaudiani, Vince; Shemin, Richard; Barnhart, Glenn; Raines, Edward; Gerdisch, Marc W; Banbury, Michael
2016-09-01
Premeasured expanded polytetrafluoroethylene chordal loops with integrated sutures for attachment to the papillary muscle and leaflet edges facilitate correction of mitral valve prolapse. Configured as a group of 3 loops (length range 12 to 24 mm), the loops are attached to a pledget that is passed through the papillary muscle and tied. Each of the loops has 2 sutures with attached needles; these needles are passed through the free edge of the leaflet and then the sutures are tied to each other, securing the chordal loop to the leaflet. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
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Nonlinear mathematical modeling and sensitivity analysis of hydraulic drive unit
NASA Astrophysics Data System (ADS)
Kong, Xiangdong; Yu, Bin; Quan, Lingxiao; Ba, Kaixian; Wu, Liujie
2015-09-01
The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity
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Loop Evolution Observed with AIA and Hi-C
NASA Technical Reports Server (NTRS)
Mulu-Moore, Fana; Winebarger, Amy R.; Cirtain, Jonathan W.; Kobayashi, Ken; Korreck, Kelly E.; Golub, Leon; Kuzin, Sergei; Walsh, Robert William; DeForest, Craig E.; De Pontieu, Bart;
2012-01-01
In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data. In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data.
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Yamashita, Takahiro; Tose, Koji; Shichida, Yoshinori
2008-01-01
G protein-coupled receptors (GPCRs) are classified into several families based on their amino acid sequences. In family 1, GPCRs such as rhodopsin and adrenergic receptor, the structure-function relationship has been extensively investigated to demonstrate that exposure of the third cytoplasmic loop is essential for selective G protein activation. In contrast, much less is known about other families. Here we prepared chimeric mutants between Gt-coupled rhodopsin and Gi/Go- and Gs-coupled glucagon-like peptide-1 (GLP-1) receptor of family 2 and tried to identify the loop region that functions at the third cytoplasmic loop position of rhodopsin. We succeeded in expressing a mutant having the first cytoplasmic loop of GLP-1 receptor and found that this mutant activated Gi and Go efficiently but did not activate Gt. Moreover, the rhodopsin mutant having the first loop of Gs-coupled secretin receptor of family 2 decreased the Gi and Go activation efficiencies. Therefore, the first loop of GLP-1 receptor would share a similar role to the third loop of rhodopsin in G protein activation. This result strongly suggested that different families of GPCRs have maintained molecular architectures of their ancestral types to generate a common mechanism, namely exposure of the cytoplasmic loop, to activate peripheral G protein.
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Insulin Patch Pumps: Their Development and Future in Closed-Loop Systems
Bohannon, Nancy J.V.
2010-01-01
Abstract Steady progress is being made toward the development of a so-called “artificial pancreas,” which may ultimately be a fully automated, closed-loop, glucose control system comprising a continuous glucose monitor, an insulin pump, and a controller. The controller will use individualized algorithms to direct delivery of insulin without user input. A major factor propelling artificial pancreas development is the substantial incidence of—and attendant patient, parental, and physician concerns about—hypoglycemia and extreme hyperglycemia associated with current means of insulin delivery for type 1 diabetes mellitus (T1DM). A successful fully automated artificial pancreas would likely reduce the frequency of and anxiety about hypoglycemia and marked hyperglycemia. Patch-pump systems (“patch pumps”) are likely to be used increasingly in the control of T1DM and may be incorporated into the artificial pancreas systems of tomorrow. Patch pumps are free of tubing, small, lightweight, and unobtrusive. This article describes features of patch pumps that have been approved for U.S. marketing or are under development. Included in the review is an introduction to control algorithms driving insulin delivery, particularly the two major types: proportional integrative derivative and model predictive control. The use of advanced algorithms in the clinical development of closed-loop systems is reviewed along with projected next steps in artificial pancreas development. PMID:20515308
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NASA Astrophysics Data System (ADS)
Opolski, Antoni
2014-12-01
Professor Antoni Opolski was actively interested in astronomy after his retirement in 1983. He especially liked to study the works of the famous astronomer Copernicus getting inspiration for his own work. Opolski started his work on planetary loops in 2011 continuing it to the end of 2012 . During this period calculations, drawings, tables, and basic descriptions of all the planets of the Solar System were created with the use of a piece of paper and a pencil only. In 2011 Antoni Opolski asked us to help him in editing the manuscript and preparing it for publication. We have been honored having the opportunity to work on articles on planetary loops with Antoni Opolski in his house for several months. In the middle of 2012 the detailed material on Jupiter was ready. However, professor Opolski improved the article by smoothing the text and preparing new, better drawings. Finally the article ''Loops of Jupiter'', written by the 99- year old astronomer, was published in the year of his 100th birthday.
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NASA Technical Reports Server (NTRS)
Thomas, Jr., Jess B. (Inventor)
1991-01-01
An improved digital phase lock loop incorporates several distinctive features that attain better performance at high loop gain and better phase accuracy. These features include: phase feedback to a number-controlled oscillator in addition to phase rate; analytical tracking of phase (both integer and fractional cycles); an amplitude-insensitive phase extractor; a more accurate method for extracting measured phase; a method for changing loop gain during a track without loss of lock; and a method for avoiding loss of sampled data during computation delay, while maintaining excellent tracking performance. The advantages of using phase and phase-rate feedback are demonstrated by comparing performance with that of rate-only feedback. Extraction of phase by the method of modeling provides accurate phase measurements even when the number-controlled oscillator phase is discontinuously updated.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Dressel, M.O.
1979-10-30
A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfacesmore » of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the different gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft. 11 claims.« less
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Dressel, Michael O.
1979-01-01
A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfaces of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the differential gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft.
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Dimensions of driving anger and their relationships with aberrant driving.
Zhang, Tingru; Chan, Alan H S; Zhang, Wei
2015-08-01
The purpose of this study was to investigate the relationship between driving anger and aberrant driving behaviours. An internet-based questionnaire survey was administered to a sample of Chinese drivers, with driving anger measured by a 14-item short Driving Anger Scale (DAS) and the aberrant driving behaviours measured by a 23-item Driver Behaviour Questionnaire (DBQ). The results of Confirmatory Factor Analysis demonstrated that the three-factor model (hostile gesture, arrival-blocking and safety-blocking) of the DAS fitted the driving anger data well. The Exploratory Factor Analysis on DBQ data differentiated four types of aberrant driving, viz. emotional violation, error, deliberate violation and maintaining progress violation. For the anger-aberration relation, it was found that only "arrival-blocking" anger was a significant positive predictor for all four types of aberrant driving behaviours. The "safety-blocking" anger revealed a negative impact on deliberate violations, a finding different from previously established positive anger-aberration relation. These results suggest that drivers with different patterns of driving anger would show different behavioural tendencies and as a result intervention strategies may be differentially effective for drivers of different profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Hardware-in-the-Loop emulator for a hydrokinetic turbine
NASA Astrophysics Data System (ADS)
Rat, C. L.; Prostean, O.; Filip, I.
2018-01-01
Hydroelectric power has proven to be an efficient and reliable form of renewable energy, but its impact on the environment has long been a source of concern. Hydrokinetic turbines are an emerging class of renewable energy technology designed for deployment in small rivers and streams with minimal environmental impact on the local ecosystem. Hydrokinetic technology represents a truly clean source of energy, having the potential to become a highly efficient method of harvesting renewable energy. However, in order to achieve this goal, extensive research is necessary. This paper presents a Hardware-in-the-Loop emulator for a run-of-the-river type hydrokinetic turbine. The HIL system uses an ABB ACS800 drive to control an induction machine as a significant means of replicating the behavior of the real turbine. The induction machine is coupled to a permanent magnet synchronous generator and the corresponding load. The ACS800 drive is controlled through the software system, which comprises of the hydrokinetic turbine real-time simulation through mathematical modeling in the LabVIEW programming environment running on a NI CompactRIO (cRIO) platform. The advantages of this method are that it can provide a means for testing many control configurations without requiring the presence of the real turbine. This paper contains the basic principles of a hydrokinetic turbine, particularly the run-of-the-river configurations along with the experimental results obtained from the HIL system.
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Optimum design of hybrid phase locked loops
NASA Technical Reports Server (NTRS)
Lee, P.; Yan, T.
1981-01-01
The design procedure of phase locked loops is described in which the analog loop filter is replaced by a digital computer. Specific design curves are given for the step and ramp input changes in phase. It is shown that the designed digital filter depends explicitly on the product of the sampling time and the noise bandwidth of the phase locked loop. This technique of optimization can be applied to the design of digital analog loops for other applications.
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Loop-quantum-gravity vertex amplitude.
Engle, Jonathan; Pereira, Roberto; Rovelli, Carlo
2007-10-19
Spin foam models are hoped to provide the dynamics of loop-quantum gravity. However, the most popular of these, the Barrett-Crane model, does not have the good boundary state space and there are indications that it fails to yield good low-energy n-point functions. We present an alternative dynamics that can be derived as a quantization of a Regge discretization of Euclidean general relativity, where second class constraints are imposed weakly. Its state space matches the SO(3) loop gravity one and it yields an SO(4)-covariant vertex amplitude for Euclidean loop gravity.
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THE CORONAL LOOP INVENTORY PROJECT: EXPANDED ANALYSIS AND RESULTS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schmelz, J. T.; Christian, G. M.; Chastain, R. A., E-mail: jschmelz@usra.edu
We have expanded upon earlier work that investigates the relative importance of coronal loops with isothermal versus multithermal cross-field temperature distributions. These results are important for determining if loops have substructure in the form of unresolved magnetic strands. We have increased the number of loops targeted for temperature analysis from 19 to 207 with the addition of 188 new loops from multiple regions. We selected all loop segments visible in the 171 Å images of the Atmospheric Imaging Assembly (AIA) that had a clean background. Eighty-six of the new loops were rejected because they could not be reliably separated frommore » the background in other AIA filters. Sixty-one loops required multithermal models to reproduce the observations. Twenty-eight loops were effectively isothermal, that is, the plasma emission to which AIA is sensitive could not be distinguished from isothermal emission, within uncertainties. Ten loops were isothermal. Also, part of our inventory was one small flaring loop, one very cool loop whose temperature distribution could not be constrained by the AIA data, and one loop with inconclusive results. Our survey can confirm an unexpected result from the pilot study: we found no isothermal loop segments where we could properly use the 171-to-193 ratio method, which would be similar to the analysis done for many loops observed with TRACE and EIT. We recommend caution to observers who assume the loop plasma is isothermal, and hope that these results will influence the direction of coronal heating models and the effort modelers spend on various heating scenarios.« less
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Study of the post-flare loops on 29 July 1973. I - Dynamics of the X-ray loops
NASA Technical Reports Server (NTRS)
Nolte, J. T.; Gerassimenko, M.; Krieger, A. S.; Petrasso, R. D.; Svestka, Z.
1979-01-01
We derive an empirical model of the X-ray emitting post-flare loops observed during the decay phase of the 29 July 1973 flare. We find that the loops are elliptical, with the brightest emitting region at the tops. We determine the height, velocity of growth, and ratio of height to width of the loops at times from 3 to 12 hr after the flare onset.
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Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump.
Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit
2017-06-09
Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.
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A simple second-order digital phase-locked loop.
NASA Technical Reports Server (NTRS)
Tegnelia, C. R.
1972-01-01
A simple second-order digital phase-locked loop has been designed for the Viking Orbiter 1975 command system. Excluding analog-to-digital conversion, implementation of the loop requires only an adder/subtractor, two registers, and a correctable counter with control logic. The loop considers only the polarity of phase error and corrects system clocks according to a filtered sequence of this polarity. The loop is insensitive to input gain variation, and therefore offers the advantage of stable performance over long life. Predictable performance is guaranteed by extreme reliability of acquisition, yet in the steady state the loop produces only a slight degradation with respect to analog loop performance.
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Frequency-modulated laser ranging sensor with closed-loop control
NASA Astrophysics Data System (ADS)
Müller, Fabian M.; Böttger, Gunnar; Janeczka, Christian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Schneider-Ramelow, Martin
2018-02-01
Advances in autonomous driving and robotics are creating high demand for inexpensive and mass-producible distance sensors. A laser ranging system (Lidar), based on the frequency-modulated continuous-wave (FMCW) method is built in this work. The benefits of an FMCW Lidar system are the low-cost components and the performance in comparison to conventional time-of-flight Lidar systems. The basic system consists of a DFB laser diode (λ= 1308 nm) and an asymmetric fiber-coupled Mach-Zehnder interferometer with a fixed delay line in one arm. Linear tuning of the laser optical frequency via injection current modulation creates a beat signal at the interferometer output. The frequency of the beat signal is proportional to the optical path difference in the interferometer. Since the laser frequency-to-current response is non-linear, a closed-loop feed-back system is designed to improve the tuning linearity, and consequently the measurement resolution. For fast active control, an embedded system with FPGA is used, resulting in a nearly linear frequency tuning, realizing a narrow peak in the Fourier spectrum of the beat signal. For free-space measurements, a setup with two distinct interferometers is built. The fully fiber-coupled Mach-Zehnder reference interferometer is part of the feed-back loop system, while the other - a Michelson interferometer - has a free-space arm with collimator lens and reflective target. A resolution of 2:0 mm for a 560 mm distance is achieved. The results for varying target distances show high consistency and a linear relation to the measured beat-frequency.
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Study of the post-flare loops on 29 July 1973. II - Physical parameters in the X-ray loops
NASA Technical Reports Server (NTRS)
Petrasso, R. D.; Nolte, J. T.; Gerassimenko, M.; Krieger, A. S.; Krogstad, R.; Seguin, F. H.; Svestka, Z.
1979-01-01
We use the filter ratio method of analysis to determine spatially resolved values of plasma parameters in the X-ray emitting post-flare loop system which developed on 29 and 30 July 1973. We find that the loops were hotter and had higher plasma pressure at their tops than near their footpoints. The loop tops were at nearly the same temperature at different places 3 hr after the flare maximum and were also at nearly this same temperature 3 and 8 hr later. Variations in brightness transverse to the loops were due to variations in emission measure. We show by consideration of radiative losses alone that energy must have been added to the hottest part of the flare, at the tops of the loops, late in the decay phase of the flare.
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Binary phase locked loops for Omega receivers
NASA Technical Reports Server (NTRS)
Chamberlin, K.
1974-01-01
An all-digital phase lock loop (PLL) is considered because of a number of problems inherent in an employment of analog PLL. The digital PLL design presented solves these problems. A single loop measures all eight Omega time slots. Memory-aiding leads to the name of this design, the memory-aided phase lock loop (MAPLL). Basic operating principles are discussed and the superiority of MAPLL over the conventional digital phase lock loop with regard to the operational efficiency for Omega applications is demonstrated.
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NASA Technical Reports Server (NTRS)
Lee, Kimyeong; Holman, Richard; Kolb, Edward W.
1987-01-01
Wilson-loop symmetry breaking is considered on a space-time of the form M4 x K, where M4 is a four-dimensional space-time and K is an internal space with nontrivial and finite fundamental group. It is shown in a simple model that the different vacua obtained by breaking a non-Abelian gauge group by Wilson loops are separated in the space of gauge potentials by a finite energy barrier. An interpolating gauge configuration is then constructed between these vacua and shown to have minimum energy. Finally some implications of this construction are discussed.
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Loop quantum cosmology and singularities.
Struyve, Ward
2017-08-15
Loop quantum gravity is believed to eliminate singularities such as the big bang and big crunch singularity. This belief is based on studies of so-called loop quantum cosmology which concerns symmetry-reduced models of quantum gravity. In this paper, the problem of singularities is analysed in the context of the Bohmian formulation of loop quantum cosmology. In this formulation there is an actual metric in addition to the wave function, which evolves stochastically (rather than deterministically as the case of the particle evolution in non-relativistic Bohmian mechanics). Thus a singularity occurs whenever this actual metric is singular. It is shown that in the loop quantum cosmology for a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker space-time with arbitrary constant spatial curvature and cosmological constant, coupled to a massless homogeneous scalar field, a big bang or big crunch singularity is never obtained. This should be contrasted with the fact that in the Bohmian formulation of the Wheeler-DeWitt theory singularities may exist.
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Optical injection phase-lock loops
NASA Astrophysics Data System (ADS)
Bordonalli, Aldario Chrestani
Locking techniques have been widely applied for frequency synchronisation of semiconductor lasers used in coherent communication and microwave signal generation systems. Two main locking techniques, the optical phase-lock loop (OPLL) and optical injection locking (OIL) are analysed in this thesis. The principal limitations on OPLL performance result from the loop propagation delay, which makes difficult the implementation of high gain and wide bandwidth loops, leading to poor phase noise suppression performance and requiring the linewidths of the semiconductor laser sources to be less than a few megahertz for practical values of loop delay. The OIL phase noise suppression is controlled by the injected power. The principal limitations of the OIL implementation are the finite phase error under locked conditions and the narrow stable locking range the system provides at injected power levels required to reduce the phase noise output of semiconductor lasers significantly. This thesis demonstrates theoretically and experimentally that it is possible to overcome the limitations of OPLL and OIL systems by combining them, to form an optical injection phase-lock loop (OIPLL). The modelling of an OIPLL system is presented and compared with the equivalent OPLL and OIL results. Optical and electrical design of an homodyne OIPLL is detailed. Experimental results are given which verify the theoretical prediction that the OIPLL would keep the phase noise suppression as high as that of the OIL system over a much wider stable locking range, even with wide linewidth lasers and long loop delays. The experimental results for lasers with summed linewidth of 36 MHz and a loop delay of 15 ns showed measured phase error variances as low as 0.006 rad2 (500 MHz bandwidth) for locking bandwidths greater than 26 GHz, compared with the equivalent OPLL phase error variance of around 1 rad2 (500 MHz bandwidth) and the equivalent OIL locking bandwidth of less than 1.2 GHz.
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Statistical Characteristic of Global Tropical Cyclone Looping Motion
NASA Astrophysics Data System (ADS)
Shen, W.; Song, J.; Wang, Y.
2016-12-01
Statistical characteristic of looping motion of tropical cyclones (TCs) in the Western North Pacific (WPAC), North Atlantic (NATL), Eastern North Pacific (EPAC), Northern Indian Ocean (NIO), Southern Indian Ocean (SIO) and South Pacific (SPAC) basins are investigated by using IBTrACS archive maintained by NOAA. From global perspective, about ten percent TCs experience a looping motion in the above six basins. The southern hemisphere (SH) including SIO and SPAC basins have higher looping percentage than the northern hemisphere (NH), while the EPAC basin has the least looping percentage. The interannual variation of the number of looping TCs are significantly correlated with that of total TCs in the NATL, SIO and SPAC basins, while there are no correlations between the EPAC and NIO basins. The numbers of looping TCs have a higher percentage in the early and late cyclone season in the NH rather than the peak period of cyclone season, while the SIO and SPAC basins have the higher looping percentage in the early and late cyclone season, respectively. The looping motion of TCs mainly concentrates on the scale of tropical depression to category 2 and has its peak value on the scale of tropical storm. The looping motion appears more frequently and has a higher percentage at the pre-mature stage than the post-mature stage of TCs in most basins except EPAC. Comparing the intensity and intensity variation caused by the looping motion, the weaker TCs tend to intensify after looping, while the more intense ones weaken.
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Space Station evolution study oxygen loop closure
NASA Technical Reports Server (NTRS)
Wood, M. G.; Delong, D.
1993-01-01
In the current Space Station Freedom (SSF) Permanently Manned Configuration (PMC), physical scars for closing the oxygen loop by the addition of oxygen generation and carbon dioxide reduction hardware are not included. During station restructuring, the capability for oxygen loop closure was deferred to the B-modules. As such, the ability to close the oxygen loop in the U.S. Laboratory module (LAB A) and the Habitation A module (HAB A) is contingent on the presence of the B modules. To base oxygen loop closure of SSF on the funding of the B-modules may not be desirable. Therefore, this study was requested to evaluate the necessary hooks and scars in the A-modules to facilitate closure of the oxygen loop at or subsequent to PMC. The study defines the scars for oxygen loop closure with impacts to cost, weight and volume and assesses the effects of byproduct venting. In addition, the recommended scenarios for closure with regard to topology and packaging are presented.
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Closed-Loop Neuromorphic Benchmarks
Stewart, Terrence C.; DeWolf, Travis; Kleinhans, Ashley; Eliasmith, Chris
2015-01-01
Evaluating the effectiveness and performance of neuromorphic hardware is difficult. It is even more difficult when the task of interest is a closed-loop task; that is, a task where the output from the neuromorphic hardware affects some environment, which then in turn affects the hardware's future input. However, closed-loop situations are one of the primary potential uses of neuromorphic hardware. To address this, we present a methodology for generating closed-loop benchmarks that makes use of a hybrid of real physical embodiment and a type of “minimal” simulation. Minimal simulation has been shown to lead to robust real-world performance, while still maintaining the practical advantages of simulation, such as making it easy for the same benchmark to be used by many researchers. This method is flexible enough to allow researchers to explicitly modify the benchmarks to identify specific task domains where particular hardware excels. To demonstrate the method, we present a set of novel benchmarks that focus on motor control for an arbitrary system with unknown external forces. Using these benchmarks, we show that an error-driven learning rule can consistently improve motor control performance across a randomly generated family of closed-loop simulations, even when there are up to 15 interacting joints to be controlled. PMID:26696820
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Two-phase Heating in Flaring Loops
NASA Astrophysics Data System (ADS)
Zhu, Chunming; Qiu, Jiong; Longcope, Dana W.
2018-03-01
We analyze and model a C5.7 two-ribbon solar flare observed by the Solar Dynamics Observatory, Hinode, and GOES on 2011 December 26. The flare is made of many loops formed and heated successively over one and half hours, and their footpoints are brightened in the UV 1600 Å before enhanced soft X-ray and EUV missions are observed in flare loops. Assuming that anchored at each brightened UV pixel is a half flaring loop, we identify more than 6700 half flaring loops, and infer the heating rate of each loop from the UV light curve at the footpoint. In each half loop, the heating rate consists of two phases: intense impulsive heating followed by a low-rate heating that is persistent for more than 20 minutes. Using these heating rates, we simulate the evolution of their coronal temperatures and densities with the model of the “enthalpy-based thermal evolution of loops.” In the model, suppression of thermal conduction is also considered. This model successfully reproduces total soft X-ray and EUV light curves observed in 15 passbands by four instruments GOES, AIA, XRT, and EVE. In this flare, a total energy of 4.9 × 1030 erg is required to heat the corona, around 40% of this energy is in the slow-heating phase. About two-fifths of the total energy used to heat the corona is radiated by the coronal plasmas, and the other three fifth transported to the lower atmosphere by thermal conduction.
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DriveWise: An Interdisciplinary Hospital-Based Driving Assessment Program
ERIC Educational Resources Information Center
O'Connor, Margaret G.; Kapust, Lissa R.; Hollis, Ann M.
2008-01-01
Health care professionals working with the elderly have opportunities through research and clinical practice to shape public policy affecting the older driver. This article describes DriveWise, an interdisciplinary hospital-based driving assessment program developed in response to clinical concerns about the driving safety of individuals with…
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Control-structure interaction in precision pointing servo loops
NASA Technical Reports Server (NTRS)
Spanos, John T.
1989-01-01
The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and pointing system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.
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Chacko, Ajay; Tikku, Tripti; Khanna, Rohit; Maurya, Rana Pratap; Srivastava, Kamna
2018-05-28
Retraction in lingual orthodontics has biomechanical differences when compared to labial orthodontics, which is not yet established. Thus, we have intended to compare the biomechanical characteristics of closed helical loop and T-loop on 1 mm activation with 30° of compensatory curvatures during retraction in lingual orthodontics. STb lingual brackets were indirectly bonded to maxillary typhodont model that was scanned to obtain FEM model. Closed helical loop (2 × 7 mm) and T-loop (6 × 2 × 7 mm) of 0.016″ × 0.016″ TMA wire were modeled without preactivation bends. Preactivation bends at 30° were given in the software. Boundary conditions were set. The force (F) and moment (M) of both the loops were determined on 1 mm activation, using ANSYS software. M/F ratio was also calculated for both the loops. T-loop exerted less force, thus increased M/F ratio as compared to closed helical loop on 1 mm activation. When torque has to be preserved in the anterior segment during retraction in lingual orthodontics, T-loop can be preferred over closed helical loop.
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Equilibrium evolution in oscillating-field current-drive experiments
NASA Astrophysics Data System (ADS)
McCollam, K. J.; Anderson, J. K.; Blair, A. P.; Craig, D.; Den Hartog, D. J.; Ebrahimi, F.; O'Connell, R.; Reusch, J. A.; Sarff, J. S.; Stephens, H. D.; Stone, D. R.; Brower, D. L.; Deng, B. H.; Ding, W. X.
2010-08-01
Oscillating-field current drive (OFCD) is a proposed method of steady-state toroidal plasma sustainment in which ac poloidal and toroidal loop voltages are applied to produce a dc plasma current. OFCD is added to standard, inductively sustained reversed-field pinch plasmas in the Madison Symmetric Torus [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. Equilibrium profiles and fluctuations during a single cycle are measured and analyzed for different relative phases between the two OFCD voltages and for OFCD off. For OFCD phases leading to the most added plasma current, the measured energy confinement is slightly better than that for OFCD off. By contrast, the phase of the maximum OFCD helicity-injection rate also has the maximum decay rate, which is ascribed to transport losses during discrete magnetic-fluctuation events induced by OFCD. Resistive-magnetohydrodynamic simulations of the experiments reproduce the observed phase dependence of the added current.
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A novel integrated chassis controller for full drive-by-wire vehicles
NASA Astrophysics Data System (ADS)
Song, Pan; Tomizuka, Masayoshi; Zong, Changfu
2015-02-01
In this paper, a systematic design with multiple hierarchical layers is adopted in the integrated chassis controller for full drive-by-wire vehicles. A reference model and the optimal preview acceleration driver model are utilised in the driver control layer to describe and realise the driver's anticipation of the vehicle's handling characteristics, respectively. Both the sliding mode control and terminal sliding mode control techniques are employed in the vehicle motion control (MC) layer to determine the MC efforts such that better tracking performance can be attained. In the tyre force allocation layer, a polygonal simplification method is proposed to deal with the constraints of the tyre adhesive limits efficiently and effectively, whereby the load transfer due to both roll and pitch is also taken into account which directly affects the constraints. By calculating the motor torque and steering angle of each wheel in the executive layer, the total workload of four wheels is minimised during normal driving, whereas the MC efforts are maximised in extreme handling conditions. The proposed controller is validated through simulation to improve vehicle stability and handling performance in both open- and closed-loop manoeuvres.
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Self-regulation of driving and its relationship to driving ability among older adults.
Baldock, M R J; Mathias, J L; McLean, A J; Berndt, A
2006-09-01
Although it is known that older drivers limit their driving, it is not known whether this self-regulation is related to actual driving ability. A sample of 104 older drivers, aged between 60 and 92, completed a questionnaire about driving habits and attitudes. Ninety of these drivers also completed a structured on-road driving test. A measure of self-regulation was derived from drivers' self-reported avoidance of difficult driving situations. The on-road driving test involved a standard assessment used to determine fitness to drive. Driving test scores for the study were based on the number of errors committed in the driving tests, with weightings given according to the seriousness of the errors. The most commonly avoided difficult driving situations, according to responses on the questionnaire, were parallel parking and driving at night in the rain, while the least avoided situation was driving alone. Poorer performance on the driving test was not related to overall avoidance of difficult driving situations. Stronger relationships were found between driving ability and avoidance of specific difficult driving situations. These specific driving situations were the ones in which the drivers had low confidence and that the drivers were most able to avoid if they wished to.
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Acquisition and Tracking Behavior of Phase-Locked Loops
NASA Technical Reports Server (NTRS)
Viterbi, A. J.
1958-01-01
Phase-locked or APC loops have found increasing applications in recent years as tracking filters, synchronizing devices, and narrowband FM discriminators. Considerable work has been performed to determine the noise-squelching properties of the loop when it is operating in or near phase lock and is functioning as a linear coherent detector. However, insufficient consideration has been devoted to the non-linear behavior of the loop when it is out of lock and in the process of pulling in. Experimental evidence has indicated that there is a strong tendency for phase-locked loops to achieve lock under most circumstances. However, the analysis which has appeared in the literature iis limited to the acquisition of a constant frequency reference signal with only one phase-locked loop filter configuration. This work represents an investigation of frequency acquisition properties of phase-locked loops for a variety of reference-signal behavior and loop configurations
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A totally diverting loop colostomy.
Merrett, N. D.; Gartell, P. C.
1993-01-01
A technique is described where the distal limb of a loop colostomy is tied with nylon or polydioxanone. This ensures total faecal diversion and dispenses with the supporting rod, enabling early application of stoma appliances. The technique does not interfere with the traditional transverse closure of a loop colostomy. PMID:8379632
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Older driver fitness-to-drive evaluation using naturalistic driving data.
Guo, Feng; Fang, Youjia; Antin, Jonathan F
2015-09-01
As our driving population continues to age, it is becoming increasingly important to find a small set of easily administered fitness metrics that can meaningfully and reliably identify at-risk seniors requiring more in-depth evaluation of their driving skills and weaknesses. Sixty driver assessment metrics related to fitness-to-drive were examined for 20 seniors who were followed for a year using the naturalistic driving paradigm. Principal component analysis and negative binomial regression modeling approaches were used to develop parsimonious models relating the most highly predictive of the driver assessment metrics to the safety-related outcomes observed in the naturalistic driving data. This study provides important confirmation using naturalistic driving methods of the relationship between contrast sensitivity and crash-related events. The results of this study provide crucial information on the continuing journey to identify metrics and protocols that could be applied to determine seniors' fitness to drive. Published by Elsevier Ltd.
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Allan, Claire; Coxon, Kristy; Bundy, Anita; Peattie, Laura; Keay, Lisa
2016-06-01
Safety concerns together with aging of the driving population has prompted research into clinic-based driving assessments. This study investigates the relationship between the DriveSafe and DriveAware assessments and restriction of driving. Community-dwelling adults aged more than 75 (n = 380) were recruited in New South Wales, Australia. Questionnaires were administered to assess driving habits and functional assessments to assess driving-related function. Self-reported restriction was prevalent in this cross-sectional sample (62%) and was related to DriveSafe scores and personal circumstances but not DriveAware scores. DriveSafe scores were correlated with better performance on the Trail-Making Test (TMT; β = -2.94, p < .0001) and better contrast sensitivity (β = 48.70, p < .0001). Awareness was associated with better performance on the TMT (β = 0.08, p < .0001). Our data suggest that DriveSafe and DriveAware are sensitive to deficits in vision and cognition, and drivers with worse DriveSafe scores self-report restricting their driving. © The Author(s) 2015.
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Wilson loops in supersymmetric gauge theories
NASA Astrophysics Data System (ADS)
Pestun, Vasily
This thesis is devoted to several exact computations in four-dimensional supersymmetric gauge field theories. In the first part of the thesis we prove conjecture due to Erickson-Semenoff-Zarembo and Drukker-Gross which relates supersymmetric circular Wilson loop operators in the N = 4 supersymmetric Yang-Mills theory with a Gaussian matrix model. We also compute the partition function and give a new matrix model formula for the expectation value of a supersymmetric circular Wilson loop operator for the pure N = 2 and the N* = 2 supersymmetric Yang-Mills theory on a four-sphere. Circular supersymmetric Wilson loops in four-dimensional N = 2 superconformal gauge theory are treated similarly. In the second part we consider supersymmetric Wilson loops of arbitrary shape restricted to a two-dimensional sphere in the four-dimensional N = 4 supersymmetric Yang-Mills theory. We show that expectation value for these Wilson loops can be exactly computed using a two-dimensional theory closely related to the topological two-dimensional Higgs-Yang-Mills theory, or two-dimensional Yang-Mills theory for the complexified gauge group.
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On-the-fly reduction of open loops
NASA Astrophysics Data System (ADS)
Buccioni, Federico; Pozzorini, Stefano; Zoller, Max
2018-01-01
Building on the open-loop algorithm we introduce a new method for the automated construction of one-loop amplitudes and their reduction to scalar integrals. The key idea is that the factorisation of one-loop integrands in a product of loop segments makes it possible to perform various operations on-the-fly while constructing the integrand. Reducing the integrand on-the-fly, after each segment multiplication, the construction of loop diagrams and their reduction are unified in a single numerical recursion. In this way we entirely avoid objects with high tensor rank, thereby reducing the complexity of the calculations in a drastic way. Thanks to the on-the-fly approach, which is applied also to helicity summation and for the merging of different diagrams, the speed of the original open-loop algorithm can be further augmented in a very significant way. Moreover, addressing spurious singularities of the employed reduction identities by means of simple expansions in rank-two Gram determinants, we achieve a remarkably high level of numerical stability. These features of the new algorithm, which will be made publicly available in a forthcoming release of the OpenLoops program, are particularly attractive for NLO multi-leg and NNLO real-virtual calculations.
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Mitotic chromosome compaction via active loop extrusion
NASA Astrophysics Data System (ADS)
Goloborodko, Anton; Imakaev, Maxim; Marko, John; Mirny, Leonid; MIT-Northwestern Team
During cell division, two copies of each chromosome are segregated from each other and compacted more than hundred-fold into the canonical X-shaped structures. According to earlier microscopic observations and the recent Hi-C study, chromosomes are compacted into arrays of consecutive loops of ~100 kilobases. Mechanisms that lead to formation of such loop arrays are largely unknown. Here we propose that, during cell division, chromosomes can be compacted by enzymes that extrude loops on chromatin fibers. First, we use computer simulations and analytical modeling to show that a system of loop-extruding enzymes on a chromatin fiber self-organizes into an array of consecutive dynamic loops. Second, we model the process of loop extrusion in 3D and show that, coupled with the topo II strand-passing activity, it leads to robust compaction and segregation of sister chromatids. This mechanism of chromosomal condensation and segregation does not require additional proteins or specific DNA markup and is robust against variations in the number and properties of such loop extruding enzymes. Work at NU was supported by the NSF through Grants DMR-1206868 and MCB-1022117, and by the NIH through Grants GM105847 and CA193419. Work at MIT was supported by the NIH through Grants GM114190 R01HG003143.
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A portable hardware-in-the-loop (HIL) device for automotive diagnostic control systems.
Palladino, A; Fiengo, G; Lanzo, D
2012-01-01
In-vehicle driving tests for evaluating the performance and diagnostic functionalities of engine control systems are often time consuming, expensive, and not reproducible. Using a hardware-in-the-loop (HIL) simulation approach, new control strategies and diagnostic functions on a controller area network (CAN) line can be easily tested in real time, in order to reduce the effort and the cost of the testing phase. Nowadays, spark ignition engines are controlled by an electronic control unit (ECU) with a large number of embedded sensors and actuators. In order to meet the rising demand of lower emissions and fuel consumption, an increasing number of control functions are added into such a unit. This work aims at presenting a portable electronic environment system, suited for HIL simulations, in order to test the engine control software and the diagnostic functionality on a CAN line, respectively, through non-regression and diagnostic tests. The performances of the proposed electronic device, called a micro hardware-in-the-loop system, are presented through the testing of the engine management system software of a 1.6 l Fiat gasoline engine with variable valve actuation for the ECU development version. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.
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Microwave generation with photonic frequency octupling using a DPMZM in a Sagnac loop
NASA Astrophysics Data System (ADS)
Gao, Yongsheng; Wen, Aijun; Li, Ningning; Wu, Xiaohui; Zhang, Huixing
2015-09-01
A photonic microwave signal generation scheme with frequency octupling is proposed and experimentally demonstrated. The scheme is based on bi-directional use of a dual-parallel Mach-Zehnder modulator (DPMZM) in a Sagnac loop. The two sub-modulators in the DPMZM are driven by two low-frequency signals with a π/2 phase difference, and the dc biases of the modulator are all set at the maximum transmission points. Due to the velocity mismatch of the modulator, only the light wave along the clockwise direction is effectively modulated by the drive signals to generate an optical signal with a carrier and ±4th order sidebands, while the modulation of the light wave along the counterclockwise direction is far less effective and can be ignored. By properly adjusting the polarization of the light wave output from the Sagnac loop, the optical carrier can be significantly suppressed at a polarizer, and then an optical signal with only ±4th order sidebands is generated. In the experiment, a pure 24-GHz microwave signal without additional phase noise from the optical system is generated using a 3-GHz local oscillator signal. As no electrical or optical filter is used, the photonic frequency octupler is of good frequency tunability.
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Bojowald, Martin
2008-01-01
Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time. Supplementary material is available for this article at 10.12942/lrr-2008-4.
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The performance of a sampled data delay lock loop implemented with a Kalman loop filter
NASA Astrophysics Data System (ADS)
Eilts, H. S.
1980-01-01
The purpose of this study is to evaluate the steady-state and transient (lock-up) performance of a tracking loop implemented with a Kalman filter. Steady-state performance criteria are errors due to measurement noise (jitter) and Doppler errors due to motion of the tracking loop. Trade-offs exist between the two criteria such that increasing performance with respect to either one will cause performance decrease with respect to the other. It is shown that by carefully selecting filter parameters reasonable performance can be obtained for both criteria simultaneously. It is also shown that lock-up performance for the loop is acceptable when these parameters are used.
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NASA Technical Reports Server (NTRS)
1987-01-01
Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.
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Osmotic mechanism of the loop extrusion process
NASA Astrophysics Data System (ADS)
Yamamoto, Tetsuya; Schiessel, Helmut
2017-09-01
The loop extrusion theory assumes that protein factors, such as cohesin rings, act as molecular motors that extrude chromatin loops. However, recent single molecule experiments have shown that cohesin does not show motor activity. To predict the physical mechanism involved in loop extrusion, we here theoretically analyze the dynamics of cohesin rings on a loop, where a cohesin loader is in the middle and unloaders at the ends. Cohesin monomers bind to the loader rather frequently and cohesin dimers bind to this site only occasionally. Our theory predicts that a cohesin dimer extrudes loops by the osmotic pressure of cohesin monomers on the chromatin fiber between the two connected rings. With this mechanism, the frequency of the interactions between chromatin segments depends on the loading and unloading rates of dimers at the corresponding sites.
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Direct-contact closed-loop heat exchanger
Berry, Gregory F.; Minkov, Vladimir; Petrick, Michael
1984-01-01
A high temperature heat exchanger with a closed loop and a heat transfer liquid within the loop, the closed loop having a first horizontal channel with inlet and outlet means for providing direct contact of a first fluid at a first temperature with the heat transfer liquid, a second horizontal channel with inlet and outlet means for providing direct contact of a second fluid at a second temperature with the heat transfer liquid, and means for circulating the heat transfer liquid.
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Driving Safety and Fitness to Drive in Sleep Disorders.
Tippin, Jon; Dyken, Mark Eric
2017-08-01
Driving an automobile while sleepy increases the risk of crash-related injury and death. Neurologists see patients with sleepiness due to obstructive sleep apnea, narcolepsy, and a wide variety of neurologic disorders. When addressing fitness to drive, the physician must weigh patient and societal health risks and regional legal mandates. The Driver Fitness Medical Guidelines published by the National Highway Traffic Safety Administration (NHTSA) and the American Association of Motor Vehicle Administrators (AAMVA) provide assistance to clinicians. Drivers with obstructive sleep apnea may continue to drive if they have no excessive daytime sleepiness and their apnea-hypopnea index is less than 20 per hour. Those with excessive daytime sleepiness or an apnea-hypopnea index of 20 per hour or more may not drive until their condition is effectively treated. Drivers with sleep disorders amenable to pharmaceutical treatment (eg, narcolepsy) may resume driving as long as the therapy has eliminated excessive daytime sleepiness. Following these guidelines, documenting compliance to recommended therapy, and using the Epworth Sleepiness Scale to assess subjective sleepiness can be helpful in determining patients' fitness to drive.
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Loop equations and bootstrap methods in the lattice
Anderson, Peter D.; Kruczenski, Martin
2017-06-17
Pure gauge theories can be formulated in terms of Wilson Loops by means of the loop equation. In the large-N limit this equation closes in the expectation value of single loops. In particular, using the lattice as a regulator, it becomes a well defined equation for a discrete set of loops. In this paper we study different numerical approaches to solving this equation.
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Mathematical Modeling of Loop Heat Pipes
NASA Technical Reports Server (NTRS)
Kaya, Tarik; Ku, Jentung; Hoang, Triem T.; Cheung, Mark L.
1998-01-01
The primary focus of this study is to model steady-state performance of a Loop Heat Pipe (LHP). The mathematical model is based on the steady-state energy balance equations at each component of the LHP. The heat exchange between each LHP component and the surrounding is taken into account. Both convection and radiation environments are modeled. The loop operating temperature is calculated as a function of the applied power at a given loop condition. Experimental validation of the model is attempted by using two different LHP designs. The mathematical model is tested at different sink temperatures and at different elevations of the loop. Tbc comparison of the calculations and experimental results showed very good agreement (within 3%). This method proved to be a useful tool in studying steady-state LHP performance characteristics.
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Te homogeneous precipitation in Ge dislocation loop vicinity
DOE Office of Scientific and Technical Information (OSTI.GOV)
Perrin Toinin, J.; Portavoce, A., E-mail: alain.portavoce@im2np.fr; Texier, M.
2016-06-06
High resolution microscopies were used to study the interactions of Te atoms with Ge dislocation loops, after a standard n-type doping process in Ge. Te atoms neither segregate nor precipitate on dislocation loops, but form Te-Ge clusters at the same depth as dislocation loops, in contradiction with usual dopant behavior and thermodynamic expectations. Atomistic kinetic Monte Carlo simulations show that Te atoms are repulsed from dislocation loops due to elastic interactions, promoting homogeneous Te-Ge nucleation between dislocation loops. This phenomenon is enhanced by coulombic interactions between activated Te{sup 2+} or Te{sup 1+} ions.
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Driving Performance Under Alcohol in Simulated Representative Driving Tasks
Kenntner-Mabiala, Ramona; Kaussner, Yvonne; Jagiellowicz-Kaufmann, Monika; Hoffmann, Sonja; Krüger, Hans-Peter
2015-01-01
Abstract Comparing drug-induced driving impairments with the effects of benchmark blood alcohol concentrations (BACs) is an approved approach to determine the clinical relevance of findings for traffic safety. The present study aimed to collect alcohol calibration data to validate findings of clinical trials that were derived from a representative test course in a dynamic driving simulator. The driving performance of 24 healthy volunteers under placebo and with 0.05% and 0.08% BACs was measured in a double-blind, randomized, crossover design. Trained investigators assessed the subjects’ driving performance and registered their driving errors. Various driving parameters that were recorded during the simulation were also analyzed. Generally, the participants performed worse on the test course (P < 0.05 for the investigators’ assessment) under the influence of alcohol. Consistent with the relevant literature, lane-keeping performance parameters were sensitive to the investigated BACs. There were significant differences between the alcohol and placebo conditions in most of the parameters analyzed. However, the total number of errors was the only parameter discriminating significantly between all three BAC conditions. In conclusion, data show that the present experimental setup is suitable for future psychopharmacological research. Thereby, for each drug to be investigated, we recommend to assess a profile of various parameters that address different levels of driving. On the basis of this performance profile, the total number of driving errors is recommended as the primary endpoint. However, this overall endpoint should be completed by a specifically sensitive parameter that is chosen depending on the effect known to be induced by the tested drug. PMID:25689289
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NASA Technical Reports Server (NTRS)
Collins, J. J.; De Luca, C. J.; Pavlik, A. E.; Roy, S. H.; Emley, M. S.; Young, L. R. (Principal Investigator)
1995-01-01
Stabilogram-diffusion analysis was used to examine how prolonged periods in microgravity affect the open-loop and closed-loop postural control mechanisms. It was hypothesized that following spaceflight: (1) the effective stochastic activity of the open-loop postural control schemes in astronauts is increased; (2) the effective stochastic activity and uncorrelated behavior, respectively, of the closed-loop postural control mechanisms in astronauts are increased; and (3) astronauts utilized open-loop postural controls schemes for shorter time intervals and smaller displacements. Four crew members and two alternates from the 14-day Spacelab Life Sciences 2 Mission were included in the study. Each subject was tested under eyes-open, quiet-standing conditions on multiple preflight and postflight days. The subjects' center-of-pressure trajectories were measured with a force platform and analyzed according to stabilogram-diffusion analysis. It was found that the effective stochastic activity of the open-loop postural control schemes in three of the four crew members was increased following spaceflight. This result is interpreted as an indication that there may be in-flight adaptations to higher-level descending postural control pathways, e.g., a postflight increase in the tonic activation of postural muscles. This change may also be the consequence of a compensatory (e.g., "stiffening") postural control strategy that is adopted by astronauts to account for general feeling of postflight unsteadiness. The crew members, as a group, did not exhibit any consistent preflight/postflight differences in the steady-state behavior of their closed-loop postural control mechanisms or in the functional interaction of their open-loop and closed-loop postural control mechanisms. These results are interpreted as indications that although there may be in-flight adaptations to the vestibular system and/or proprioceptive system, input from the visual system can compensate for such changes
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REVIEWS OF TOPICAL PROBLEMS: Coronal magnetic loops
NASA Astrophysics Data System (ADS)
Zaitsev, Valerii V.; Stepanov, Alexander V.
2008-11-01
The goal of this review is to outline some new ideas in the physics of coronal magnetic loops, the fundamental structural elements of the atmospheres of the Sun and flaring stars, which are involved in phenomena such as stellar coronal heating, flare energy release, charged particle acceleration, and the modulation of optical, radio, and X-ray emissions. The Alfvén-Carlqvist view of a coronal loop as an equivalent electric circuit allows a good physical understanding of loop processes. Describing coronal loops as MHD-resonators explains various ways in which flaring emissions from the Sun and stars are modulated, whereas modeling them by magnetic mirror traps allows one to describe the dynamics and emission of high-energy particles. Based on these approaches, loop plasma and fast particle parameters are obtained and models for flare energy release and stellar corona heating are developed.
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Papenfort, Kai; Espinosa, Elena; Casadesús, Josep; Vogel, Jörg
2015-08-25
Horizontal gene transfer via plasmid conjugation is a major driving force in microbial evolution but constitutes a complex process that requires synchronization with the physiological state of the host bacteria. Although several host transcription factors are known to regulate plasmid-borne transfer genes, RNA-based regulatory circuits for host-plasmid communication remain unknown. We describe a posttranscriptional mechanism whereby the Hfq-dependent small RNA, RprA, inhibits transfer of pSLT, the virulence plasmid of Salmonella enterica. RprA employs two separate seed-pairing domains to activate the mRNAs of both the sigma-factor σ(S) and the RicI protein, a previously uncharacterized membrane protein here shown to inhibit conjugation. Transcription of ricI requires σ(S) and, together, RprA and σ(S) orchestrate a coherent feedforward loop with AND-gate logic to tightly control the activation of RicI synthesis. RicI interacts with the conjugation apparatus protein TraV and limits plasmid transfer under membrane-damaging conditions. To our knowledge, this study reports the first small RNA-controlled feedforward loop relying on posttranscriptional activation of two independent targets and an unexpected role of the conserved RprA small RNA in controlling extrachromosomal DNA transfer.
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Direct-contact closed-loop heat exchanger
Berry, G.F.; Minkov, V.; Petrick, M.
1981-11-02
A high temperature heat exchanger is disclosed which has a closed loop and a heat transfer liquid within the loop, the closed loop having a first horizontal channel with inlet and outlet means for providing direct contact of a first fluid at a first temperature with the heat transfer liquid, a second horizontal channel with inlet and outlet means for providing direct contact of a second fluid at a second temperature with the heat transfer liquid, and means for circulating the heat transfer liquid.
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ERIC Educational Resources Information Center
Williams-Wright, Vera
2013-01-01
The purpose of this research study was two-fold. The first purpose was to investigate the impact of looping on academic achievement of students in selected public schools in Mississippi. The students' results on the 2010 and 2011 Mississippi Curriculum Test, Second Edition (MCT2) were used to determine whether looping students score differently in…
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Jeliazkov, Jeliazko R.; Sljoka, Adnan; Kuroda, Daisuke; Tsuchimura, Nobuyuki; Katoh, Naoki; Tsumoto, Kouhei; Gray, Jeffrey J.
2018-01-01
Antibodies can rapidly evolve in specific response to antigens. Affinity maturation drives this evolution through cycles of mutation and selection leading to enhanced antibody specificity and affinity. Elucidating the biophysical mechanisms that underlie affinity maturation is fundamental to understanding B-cell immunity. An emergent hypothesis is that affinity maturation reduces the conformational flexibility of the antibody’s antigen-binding paratope to minimize entropic losses incurred upon binding. In recent years, computational and experimental approaches have tested this hypothesis on a small number of antibodies, often observing a decrease in the flexibility of the complementarity determining region (CDR) loops that typically comprise the paratope and in particular the CDR-H3 loop, which contributes a plurality of antigen contacts. However, there were a few exceptions and previous studies were limited to a small handful of cases. Here, we determined the structural flexibility of the CDR-H3 loop for thousands of recent homology models of the human peripheral blood cell antibody repertoire using rigidity theory. We found no clear delineation in the flexibility of naïve and antigen-experienced antibodies. To account for possible sources of error, we additionally analyzed hundreds of human and mouse antibodies in the Protein Data Bank through both rigidity theory and B-factor analysis. By both metrics, we observed only a slight decrease in the CDR-H3 loop flexibility when comparing affinity matured antibodies to naïve antibodies, and the decrease was not as drastic as previously reported. Further analysis, incorporating molecular dynamics simulations, revealed a spectrum of changes in flexibility. Our results suggest that rigidification may be just one of many biophysical mechanisms for increasing affinity. PMID:29545810
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A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.
Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A
2005-11-01
While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.
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Protein Loop Structure Prediction Using Conformational Space Annealing.
Heo, Seungryong; Lee, Juyong; Joo, Keehyoung; Shin, Hang-Cheol; Lee, Jooyoung
2017-05-22
We have developed a protein loop structure prediction method by combining a new energy function, which we call E PLM (energy for protein loop modeling), with the conformational space annealing (CSA) global optimization algorithm. The energy function includes stereochemistry, dynamic fragment assembly, distance-scaled finite ideal gas reference (DFIRE), and generalized orientation- and distance-dependent terms. For the conformational search of loop structures, we used the CSA algorithm, which has been quite successful in dealing with various hard global optimization problems. We assessed the performance of E PLM with two widely used loop-decoy sets, Jacobson and RAPPER, and compared the results against the DFIRE potential. The accuracy of model selection from a pool of loop decoys as well as de novo loop modeling starting from randomly generated structures was examined separately. For the selection of a nativelike structure from a decoy set, E PLM was more accurate than DFIRE in the case of the Jacobson set and had similar accuracy in the case of the RAPPER set. In terms of sampling more nativelike loop structures, E PLM outperformed E DFIRE for both decoy sets. This new approach equipped with E PLM and CSA can serve as the state-of-the-art de novo loop modeling method.
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3D MHD Models of Active Region Loops
NASA Technical Reports Server (NTRS)
Ofman, Leon
2004-01-01
Present imaging and spectroscopic observations of active region loops allow to determine many physical parameters of the coronal loops, such as the density, temperature, velocity of flows in loops, and the magnetic field. However, due to projection effects many of these parameters remain ambiguous. Three dimensional imaging in EUV by the STEREO spacecraft will help to resolve the projection ambiguities, and the observations could be used to setup 3D MHD models of active region loops to study the dynamics and stability of active regions. Here the results of 3D MHD models of active region loops are presented, and the progress towards more realistic 3D MHD models of active regions. In particular the effects of impulsive events on the excitation of active region loop oscillations, and the generation, propagations and reflection of EIT waves are shown. It is shown how 3D MHD models together with 3D EUV observations can be used as a diagnostic tool for active region loop physical parameters, and to advance the science of the sources of solar coronal activity.
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EXAMINATION OF Zr AND Ti RECOMBINER LOOP SPECIMENS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Rittenhouse, P.L.
1958-12-19
Cold-worked specimens of iodide zirconium, Zircaloy-2, iodide titanium, and A-55 titanium were tested in a high-pressure recombiner loop in an attempt to duplicate anomalous results obtained in a prior recombiner loop. Hydrogen analyses and metallographic examinations were made on all specimens. The titanium materials and Zircaloy-2 picked up major amounts of hydrogen in the cell section. None of the materials tested showed appreciable hydrogen absorption in the recombiner section. Complete recrystallization occurred in all cell specimens while only Zircaloy-2, of the recombiner specimens, showed any degree of recrystallization. No explanation for this behavior can be given. A survnnary of themore » data obtained in previous recombiner loops is compared with the results of this loop. Conclusions were based on the results of three recombiner loops. Primarlly because of the hydrogen absorption data obtained in all three recombiner loops it is recommended that the zirconium and titunium materials tested not be used in environments similar to those encountered in high pressure recombiner loops. (auth)« less
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Closed-loop control of gimbal-less MEMS mirrors for increased bandwidth in LiDAR applications
NASA Astrophysics Data System (ADS)
Milanović, Veljko; Kasturi, Abhishek; Yang, James; Hu, Frank
2017-05-01
In 2016, we presented a low SWaP wirelessly controlled MEMS mirror-based LiDAR prototype which utilized an OEM laser rangefinder for distance measurement [1]. The MEMS mirror was run in open loop based on its exceptionally fast design and high repeatability performance. However, to further extend the bandwidth and incorporate necessary eyesafety features, we recently focused on providing mirror position feedback and running the system in closed loop control. Multiple configurations of optical position sensors, mounted on both the front- and the back-side of the MEMS mirror, have been developed and will be presented. In all cases, they include a light source (LED or laser) and a 2D photosensor. The most compact version is mounted on the backside of the MEMS mirror ceramic package and can "view" the mirror's backside through openings in the mirror's PCB and its ceramic carrier. This version increases the overall size of the MEMS mirror submodule from 12mm x 12mm x 4mm to 15mm x 15mm x 7mm. The sensors also include optical and electronic filtering to reduce effects of any interference from the application laser illumination. With relatively simple FPGA-based PID control running at the sample rate of 100 kHz, we could configure the overall response of the system to fully utilize the MEMS mirror's native bandwidth which extends well beyond its first resonance. When compared to the simple open loop method of suppressing overshoot and ringing which significantly limits bandwidth utilization, running the mirrors in closed loop control increased the bandwidth to nearly 3.7 times. A 2.0mm diameter integrated MEMS mirror with a resonant frequency of 1300 Hz was limited to 500Hz bandwidth in open loop driving but was increased to 3kHz bandwidth with the closed loop controller. With that bandwidth it is capable of very sharply defined uniform-velocity scans (sawtooth or triangle waveforms) which are highly desired in scanned mirror LiDAR systems. A 2.4mm diameter mirror with
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Iterative LQG Controller Design Through Closed-Loop Identification
NASA Technical Reports Server (NTRS)
Hsiao, Min-Hung; Huang, Jen-Kuang; Cox, David E.
1996-01-01
This paper presents an iterative Linear Quadratic Gaussian (LQG) controller design approach for a linear stochastic system with an uncertain open-loop model and unknown noise statistics. This approach consists of closed-loop identification and controller redesign cycles. In each cycle, the closed-loop identification method is used to identify an open-loop model and a steady-state Kalman filter gain from closed-loop input/output test data obtained by using a feedback LQG controller designed from the previous cycle. Then the identified open-loop model is used to redesign the state feedback. The state feedback and the identified Kalman filter gain are used to form an updated LQC controller for the next cycle. This iterative process continues until the updated controller converges. The proposed controller design is demonstrated by numerical simulations and experiments on a highly unstable large-gap magnetic suspension system.
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A dual-loop model of the human controller
NASA Technical Reports Server (NTRS)
Hess, R. A.
1977-01-01
A representative model of the human controller in single-axis compensatory tracking tasks that exhibits an internal feedback loop which is not evident in single-loop models now in common use is presented. This hypothetical inner-loop involves a neuromuscular command signal derived from the time rate of change of controlled element output which is due to control activity. It is not contended that the single-loop human controller models now in use are incorrect, but that they contain an implicit but important internal loop closure, which, if explicitly considered, can account for a good deal of the adaptive nature of the human controller in a systematic manner.
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Cable, R.E.; Goode, W.B. Jr.; Henderson, W.K.; Montillon, G.H.
1962-06-26
An improved anode assembly is deslgned for use in electrolytlc cells ln the productlon of hydrogen and fluorlne from a moIten electrolyte. The anode assembly comprises a copper post, a copper hanger supported by the post, a plurality of carbon anode members, and bolt means for clamplng half of the anode members to one slde of the hanger and for clamplng the other half of the anode members to the other slde of the hanger. The heads of the clamplng bolts are recessed withln the anode members and carbon plugs are inserted ln the recesses above the bolt heads to protect the boIts agalnst corroslon. A copper washer is provided under the head of each clamplng boIt such that the anode members can be tightly clamped to the hanger with a resultant low anode jolnt resistance. (AEC)
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Closed-loop fiber optic gyroscope with homodyne detection
NASA Astrophysics Data System (ADS)
Zhu, Yong; Qin, BingKun; Chen, Shufen
1996-09-01
Interferometric fiber optic gyroscope (IFOG) has been analyzed with autocontrol theory in this paper. An open-loop IFOG system is not able to restrain the bias drift, but a closed-loop IFOG system can do it very well using negative feedback in order to suppress zero drift. The result of our theoretic analysis and computer simulation indicate that the bias drift of a closed-loop system is smaller than an open- loop one.
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Studying DNA Looping by Single-Molecule FRET
Le, Tung T.; Kim, Harold D.
2014-01-01
Bending of double-stranded DNA (dsDNA) is associated with many important biological processes such as DNA-protein recognition and DNA packaging into nucleosomes. Thermodynamics of dsDNA bending has been studied by a method called cyclization which relies on DNA ligase to covalently join short sticky ends of a dsDNA. However, ligation efficiency can be affected by many factors that are not related to dsDNA looping such as the DNA structure surrounding the joined sticky ends, and ligase can also affect the apparent looping rate through mechanisms such as nonspecific binding. Here, we show how to measure dsDNA looping kinetics without ligase by detecting transient DNA loop formation by FRET (Fluorescence Resonance Energy Transfer). dsDNA molecules are constructed using a simple PCR-based protocol with a FRET pair and a biotin linker. The looping probability density known as the J factor is extracted from the looping rate and the annealing rate between two disconnected sticky ends. By testing two dsDNAs with different intrinsic curvatures, we show that the J factor is sensitive to the intrinsic shape of the dsDNA. PMID:24998459
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Studying DNA looping by single-molecule FRET.
Le, Tung T; Kim, Harold D
2014-06-28
Bending of double-stranded DNA (dsDNA) is associated with many important biological processes such as DNA-protein recognition and DNA packaging into nucleosomes. Thermodynamics of dsDNA bending has been studied by a method called cyclization which relies on DNA ligase to covalently join short sticky ends of a dsDNA. However, ligation efficiency can be affected by many factors that are not related to dsDNA looping such as the DNA structure surrounding the joined sticky ends, and ligase can also affect the apparent looping rate through mechanisms such as nonspecific binding. Here, we show how to measure dsDNA looping kinetics without ligase by detecting transient DNA loop formation by FRET (Fluorescence Resonance Energy Transfer). dsDNA molecules are constructed using a simple PCR-based protocol with a FRET pair and a biotin linker. The looping probability density known as the J factor is extracted from the looping rate and the annealing rate between two disconnected sticky ends. By testing two dsDNAs with different intrinsic curvatures, we show that the J factor is sensitive to the intrinsic shape of the dsDNA.
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Perception as a closed-loop convergence process.
Ahissar, Ehud; Assa, Eldad
2016-05-09
Perception of external objects involves sensory acquisition via the relevant sensory organs. A widely-accepted assumption is that the sensory organ is the first station in a serial chain of processing circuits leading to an internal circuit in which a percept emerges. This open-loop scheme, in which the interaction between the sensory organ and the environment is not affected by its concurrent downstream neuronal processing, is strongly challenged by behavioral and anatomical data. We present here a hypothesis in which the perception of external objects is a closed-loop dynamical process encompassing loops that integrate the organism and its environment and converging towards organism-environment steady-states. We discuss the consistency of closed-loop perception (CLP) with empirical data and show that it can be synthesized in a robotic setup. Testable predictions are proposed for empirical distinction between open and closed loop schemes of perception.
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Equilibrium models of coronal loops that involve curvature and buoyancy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hindman, Bradley W.; Jain, Rekha, E-mail: hindman@solarz.colorado.edu
2013-12-01
We construct magnetostatic models of coronal loops in which the thermodynamics of the loop is fully consistent with the shape and geometry of the loop. This is achieved by treating the loop as a thin, compact, magnetic fibril that is a small departure from a force-free state. The density along the loop is related to the loop's curvature by requiring that the Lorentz force arising from this deviation is balanced by buoyancy. This equilibrium, coupled with hydrostatic balance and the ideal gas law, then connects the temperature of the loop with the curvature of the loop without resorting to amore » detailed treatment of heating and cooling. We present two example solutions: one with a spatially invariant magnetic Bond number (the dimensionless ratio of buoyancy to Lorentz forces) and the other with a constant radius of the curvature of the loop's axis. We find that the density and temperature profiles are quite sensitive to curvature variations along the loop, even for loops with similar aspect ratios.« less
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Digital Filters for Digital Phase-locked Loops
NASA Technical Reports Server (NTRS)
Simon, M.; Mileant, A.
1985-01-01
An s/z hybrid model for a general phase locked loop is proposed. The impact of the loop filter on the stability, gain margin, noise equivalent bandwidth, steady state error and time response is investigated. A specific digital filter is selected which maximizes the overall gain margin of the loop. This filter can have any desired number of integrators. Three integrators are sufficient in order to track a phase jerk with zero steady state error at loop update instants. This filter has one zero near z = 1.0 for each integrator. The total number of poles of the filter is equal to the number of integrators plus two.
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Protein-mediated looping of DNA under tension requires supercoiling
Yan, Yan; Leng, Fenfei; Finzi, Laura; Dunlap, David
2018-01-01
Abstract Protein-mediated DNA looping is ubiquitous in chromatin organization and gene regulation, but to what extent supercoiling or nucleoid associated proteins promote looping is poorly understood. Using the lac repressor (LacI), a paradigmatic loop-mediating protein, we measured LacI-induced looping as a function of either supercoiling or the concentration of the HU protein, an abundant nucleoid protein in Escherichia coli. Negative supercoiling to physiological levels with magnetic tweezers easily drove the looping probability from 0 to 100% in single DNA molecules under slight tension that likely exists in vivo. In contrast, even saturating (micromolar) concentrations of HU could not raise the looping probability above 30% in similarly stretched DNA or 80% in DNA without tension. Negative supercoiling is required to induce significant looping of DNA under any appreciable tension. PMID:29365152
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LMFBR with booster pump in pumping loop
Rubinstein, H.J.
1975-10-14
A loop coolant circulation system is described for a liquid metal fast breeder reactor (LMFBR) utilizing a low head, high specific speed booster pump in the hot leg of the coolant loop with the main pump located in the cold leg of the loop, thereby providing the advantages of operating the main pump in the hot leg with the reliability of cold leg pump operation.
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Phase-lock loop frequency control and the dropout problem
NASA Technical Reports Server (NTRS)
Attwood, S.; Kline, A. J.
1968-01-01
Technique automatically sets the frequency of narrow band phase-lock loops within automatic lock-in-range. It presets a phase-lock loop to a desired center frequency with a closed loop electronic frequency discriminator and holds the phase-lock loop to that center frequency until lock is achieved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
D Critton; L Tautz; R Page
2011-12-31
Phosphotyrosine hydrolysis by protein tyrosine phosphatases (PTPs) involves substrate binding by the PTP loop and closure over the active site by the WPD loop. The E loop, located immediately adjacent to the PTP and WPD loops, is conserved among human PTPs in both sequence and structure, yet the role of this loop in substrate binding and catalysis is comparatively unexplored. Hematopoietic PTP (HePTP) is a member of the kinase interaction motif (KIM) PTP family. Compared to other PTPs, KIM-PTPs have E loops that are unique in both sequence and structure. In order to understand the role of the E loopmore » in the transition between the closed state and the open state of HePTP, we identified a novel crystal form of HePTP that allowed the closed-state-to-open-state transition to be observed within a single crystal form. These structures, which include the first structure of the HePTP open state, show that the WPD loop adopts an 'atypically open' conformation and, importantly, that ligands can be exchanged at the active site, which is critical for HePTP inhibitor development. These structures also show that tetrahedral oxyanions bind at a novel secondary site and function to coordinate the PTP, WPD, and E loops. Finally, using both structural and kinetic data, we reveal a novel role for E-loop residue Lys182 in enhancing HePTP catalytic activity through its interaction with Asp236 of the WPD loop, providing the first evidence for the coordinated dynamics of the WPD and E loops in the catalytic cycle, which, as we show, is relevant to multiple PTP families.« less
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Current systems of coronal loops in 3D MHD simulations
NASA Astrophysics Data System (ADS)
Warnecke, J.; Chen, F.; Bingert, S.; Peter, H.
2017-11-01
Aims: We study the magnetic field and current structure associated with a coronal loop. Through this we investigate to what extent the assumptions of a force-free magnetic field break down and where they might be justified. Methods: We analyze a three-dimensional (3D) magnetohydrodynamic (MHD) model of the solar corona in an emerging active region with the focus on the structure of the forming coronal loops. The lower boundary of this simulation is taken from a model of an emerging active region. As a consequence of the emerging magnetic flux and the horizontal motions at the surface a coronal loop forms self-consistently. We investigate the current density along magnetic field lines inside (and outside) this loop and study the magnetic and plasma properties in and around this loop. The loop is defined as the bundle of field lines that coincides with enhanced emission in extreme UV. Results: We find that the total current along the emerging loop changes its sign from being antiparallel to parallel to the magnetic field. This is caused by the inclination of the loop together with the footpoint motion. Around the loop, the currents form a complex non-force-free helical structure. This is directly related to a bipolar current structure at the loop footpoints at the base of the corona and a local reduction of the background magnetic field (I.e., outside the loop) caused by the plasma flow into and along the loop. Furthermore, the locally reduced magnetic pressure in the loop allows the loop to sustain a higher density, which is crucial for the emission in extreme UV. The action of the flow on the magnetic field hosting the loop turns out to also be responsible for the observed squashing of the loop. Conclusions: The complex magnetic field and current system surrounding it can only be modeled in 3D MHD models where the magnetic field has to balance the plasma pressure. A one-dimensional coronal loop model or a force-free extrapolation cannot capture the current system
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Innovative hybrid pile oscillator technique in the Minerve reactor: open loop vs. closed loop
NASA Astrophysics Data System (ADS)
Geslot, Benoit; Gruel, Adrien; Bréaud, Stéphane; Leconte, Pierre; Blaise, Patrick
2018-01-01
Pile oscillator techniques are powerful methods to measure small reactivity worth of isotopes of interest for nuclear data improvement. This kind of experiments has long been implemented in the Mineve experimental reactor, operated by CEA Cadarache. A hybrid technique, mixing reactivity worth estimation and measurement of small changes around test samples is presented here. It was made possible after the development of high sensitivity miniature fission chambers introduced next to the irradiation channel. A test campaign, called MAESTRO-SL, took place in 2015. Its objective was to assess the feasibility of the hybrid method and investigate the possibility to separate mixed neutron effects, such as fission/capture or scattering/capture. Experimental results are presented and discussed in this paper, which focus on comparing two measurements setups, one using a power control system (closed loop) and another one where the power is free to drift (open loop). First, it is demonstrated that open loop is equivalent to closed loop. Uncertainty management and methods reproducibility are discussed. Second, results show that measuring the flux depression around oscillated samples provides valuable information regarding partial neutron cross sections. The technique is found to be very sensitive to the capture cross section at the expense of scattering, making it very useful to measure small capture effects of highly scattering samples.
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Architecture of kangaroo rat inner medulla: segmentation of descending thin limb of Henle's loop.
Urity, Vinoo B; Issaian, Tadeh; Braun, Eldon J; Dantzler, William H; Pannabecker, Thomas L
2012-03-15
We hypothesize that the inner medulla of the kangaroo rat Dipodomys merriami, a desert rodent that concentrates its urine to more than 6,000 mosmol/kgH(2)O water, provides unique examples of architectural features necessary for production of highly concentrated urine. To investigate this architecture, inner medullary nephron segments in the initial 3,000 μm below the outer medulla were assessed with digital reconstructions from physical tissue sections. Descending thin limbs of Henle (DTLs), ascending thin limbs of Henle (ATLs), and collecting ducts (CDs) were identified by immunofluorescence using antibodies that label segment-specific proteins associated with transepithelial water flux (aquaporin 1 and 2, AQP1 and AQP2) and chloride flux (the chloride channel ClC-K1); all tubules and vessels were labeled with wheat germ agglutinin. In the outer 3,000 μm of the inner medulla, AQP1-positive DTLs lie at the periphery of groups of CDs. ATLs lie inside and outside the groups of CDs. Immunohistochemistry and reconstructions of loops that form their bends in the outer 3,000 μm of the inner medulla show that, relative to loop length, the AQP1-positive segment of the kangaroo rat is significantly longer than that of the Munich-Wistar rat. The length of ClC-K1 expression in the prebend region at the terminal end of the descending side of the loop in kangaroo rat is about 50% shorter than that of the Munich-Wistar rat. Tubular fluid of the kangaroo rat DTL may approach osmotic equilibrium with interstitial fluid by water reabsorption along a relatively longer tubule length, compared with Munich-Wistar rat. A relatively shorter-length prebend segment may promote a steeper reabsorptive driving force at the loop bend. These structural features predict functionality that is potentially significant in the production of a high urine osmolality in the kangaroo rat.
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Sweeping Arches and Loops [video
2014-07-10
Two active regions with their intense magnetic fields produced towering arches and spiraling coils of solar loops above them (June 29 - July 1, 2014) as they rotated into view. When viewed in extreme ultraviolet light, magnetic field lines are revealed by charged particles that travel along them. These active regions appear as dark sunspots when viewed in filtered light. Note the small blast in the upper of the two major active regions, followed by more coils of loops as the region reorganizes itself. The still was taken on June 30 at 10:33 UT. Credit: NASA/Solar Dynamics Observatory Two active regions with their intense magnetic fields produced towering arches and spiraling coils of solar loops above them (June 29 - July 1, 2014) as they rotated into view. When viewed in extreme ultraviolet light, magnetic field lines are revealed by charged particles that travel along them. These active regions appear as dark sunspots when viewed in filtered light. Note the small blast in the upper of the two major active regions, followed by more coils of loops as the region reorganizes itself. The still was taken on June 30 at 10:33 UT. Credit: Solar Dynamics Observatory/NASA.
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Smorti, Martina; Guarnieri, Silvia
2016-01-01
The present study examined the contribution of impulsiveness and aggressive and negative emotional driving to the prediction of traffic violations and accidents taking into account potential mediation effects. Three hundred and four young drivers completed self-report measures assessing impulsiveness, aggressive and negative emotional driving, driving violations, and accidents. Structural equation modeling was used to assess the direct and indirect effects of impulsiveness on violations and accidents among young drivers through aggressive and negative emotional driving. Impulsiveness only indirectly influenced drivers' violations on the road via both the behavioral and emotional states of the driver. On the contrary, impulsiveness was neither directly nor indirectly associated with traffic accidents. Therefore, impulsiveness modulates young drivers' behavioral and emotional states while driving, which in turn influences risky driving.
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Acceptance of drinking and driving and alcohol-involved driving crashes in California.
MacLeod, Kara E; Karriker-Jaffe, Katherine J; Ragland, David R; Satariano, William A; Kelley-Baker, Tara; Lacey, John H
2015-08-01
Alcohol-impaired driving accounts for substantial proportion of traffic-related fatalities in the U.S. Risk perceptions for drinking and driving have been associated with various measures of drinking and driving behavior. In an effort to understand how to intervene and to better understand how risk perceptions may be shaped, this study explored whether an objective environmental-level measure (proportion of alcohol-involved driving crashes in one's residential city) were related to individual-level perceptions and behavior. Using data from a 2012 cross-sectional roadside survey of 1147 weekend nighttime drivers in California, individual-level self-reported acceptance of drinking and driving and past-year drinking and driving were merged with traffic crash data using respondent ZIP codes. Population average logistic regression modeling was conducted for the odds of acceptance of drinking and driving and self-reported, past-year drinking and driving. A non-linear relationship between city-level alcohol-involved traffic crashes and individual-level acceptance of drinking and driving was found. Acceptance of drinking and driving did not mediate the relationship between the proportion of alcohol-involved traffic crashes and self-reported drinking and driving behavior. However, it was directly related to behavior among those most likely to drink outside the home. The present study surveys a particularly relevant population and is one of few drinking and driving studies to evaluate the relationship between an objective environmental-level crash risk measure and individual-level risk perceptions. In communities with both low and high proportions of alcohol-involved traffic crashes there was low acceptance of drinking and driving. This may mean that in communities with low proportions of crashes, citizens have less permissive norms around drinking and driving, whereas in communities with a high proportion of crashes, the incidence of these crashes may serve as an
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Acceptance of drinking and driving and alcohol-involved driving crashes in California
Karriker-Jaffe, Katherine J.; Ragland, David R.; Satariano, William A.; Kelley-Baker, Tara; Lacey, John H.
2016-01-01
Background Alcohol-impaired driving accounts for substantial proportion of traffic-related fatalities in the U.S. Risk perceptions for drinking and driving have been associated with various measures of drinking and driving behavior. In an effort to understand how to intervene and to better understand how risk perceptions may be shaped, this study explored whether an objective environmental-level measure (proportion of alcohol-involved driving crashes in one's residential city) were related to individual-level perceptions and behavior. Methods Using data from a 2012 cross-sectional roadside survey of 1,147 weekend nighttime drivers in California, individual-level self-reported acceptance of drinking and driving and past-year drinking and driving were merged with traffic crash data using respondent ZIP codes. Population average logistic regression modeling was conducted for the odds of acceptance of drinking and driving and self-reported, past-year drinking and driving. Results A non-linear relationship between city-level alcohol-involved traffic crashes and individual-level acceptance of drinking and driving was found. Acceptance of drinking and driving did not mediate the relationship between the proportion of alcohol-involved traffic crashes and self-reported drinking and driving behavior. However, it was directly related to behavior among those most likely to drink outside the home. Discussion The present study surveys a particularly relevant population and is one of few drinking and driving studies to evaluate the relationship between an objective environmental-level crash risk measure and individual-level risk perceptions. In communities with both low and high proportions of alcohol-involved traffic crashes there was low acceptance of drinking and driving. This may mean that in communities with low proportions of crashes, citizens have less permissive norms around drinking and driving, whereas in communities with a high proportion of crashes, the incidence of
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Feedback loop compensates for rectifier nonlinearity
NASA Technical Reports Server (NTRS)
1966-01-01
Signal processing circuit with two negative feedback loops rectifies two sinusoidal signals which are 180 degrees out of phase and produces a single full-wave rectified output signal. Each feedback loop incorporates a feedback rectifier to compensate for the nonlinearity of the circuit.
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Surface NMR imaging with simultaneously energized transmission loops
NASA Astrophysics Data System (ADS)
Irons, T. P.; Kass, A.; Parsekian, A.
2016-12-01
Surface nuclear magnetic resonance (sNMR) is a unique geophysical technique which allows for the direct detection of liquid-phase water. In saturated media the sNMR response also provides estimates of hydrologic properties including porosity and permeability. The most common survey deployment consists of a single coincident loop performing both transmission and receiving. Because the sNMR method is relatively slow, tomography using coincident loops is time-intensive. Surveys using multiple receiver loops (but a single transmitter) provide additional sensitivity; however, they still require iterating transmission over the loops, and do not decrease survey acquisition time. In medical rotating frame imaging, arrays of transmitters are employed in order to decrease acquisition time, whilst optimizing image resolving power-a concept which we extend to earth's field imaging. Using simultaneously energized transmission loops decreases survey time linearly with the number of channels. To demonstrate the efficacy and benefits of multiple transmission loops, we deployed simultaneous sNMR transmission arrays using minimally coupled loops and a specially modified instrument at the Red Buttes Hydrogeophysics Experiment Site-a well-characterized location near Laramie, Wyoming. The proposed survey proved capable of acquiring multiple-channel imaging data with comparable noise levels to figure-eight configurations. Finally, the channels can be combined after acquisition or inverted simultaneously to provide composite datasets and images. This capability leverages the improved near surface resolving power of small loops but retains sensitivity to deep media through the use of synthetic aperature receivers. As such, simultaneously acquired loop arrays provide a great deal of flexibility.
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Automated Driving System Architecture to Ensure Safe Delegation of Driving Authority
NASA Astrophysics Data System (ADS)
YUN, Sunkil; NISHIMURA, Hidekazu
2016-09-01
In this paper, the architecture of an automated driving system (ADS) is proposed to ensure safe delegation of driving authority between the ADS and a driver. Limitations of the ADS functions may activate delegation of driving authority to a driver. However, it leads to severe consequences in emergency situations where a driver may be drowsy or distracted. To address these issues, first, the concept model for the ADS in the situation for delegation of driving authority is described taking the driver's behaviour and state into account. Second, the behaviour / state of a driver and functional flow / state of ADS and the interactions between them are modelled to understand the context where the ADS requests to delegate the driving authority to a driver. Finally, the proposed architecture of the ADS is verified under the simulations based on the emergency braking scenarios. In the verification process using simulation, we have derived the necessary condition for safe delegation of driving authority is that the ADS should assist s driver even after delegating driving authority to a driver who has not enough capability to regain control of the driving task.
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Driving reduction and cessation : transitioning to not driving.
DOT National Transportation Integrated Search
2009-09-01
This project examined the process of driving reduction and cessation from the perspective of older adults (current and former drivers) and adult children. The objectives were to identify common markers of the process of driving cessation and to gain ...
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A class of optimum digital phase locked loops
NASA Technical Reports Server (NTRS)
Kumar, R.; Hurd, W. J.
1986-01-01
This paper presents a class of optimum digital filters for digital phase locked loops, for the important case in which the maximum update rate of the loop filter and numerically controlled oscillator (NCO) is limited. This case is typical when the loop filter is implemented in a microprocessor. In these situations, pure delay is encountered in the loop transfer function and thus the stability and gain margin of the loop are of crucial interest. The optimum filters designed for such situations are evaluated in terms of their gain margin for stability, dynamic error, and steady-state error performance. For situations involving considerably high phase dynamics an adaptive and programmable implementation is also proposed to obtain an overall optimum strategy.
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In-Flight Performance of the TES Loop Heat Pipe Rejection System: Seven Years in Space
NASA Technical Reports Server (NTRS)
Rodriguez, Jose I.; Na-Nakornpanom, Arthur
2012-01-01
The Tropospheric Emission Spectrometer (TES) instrument heat rejection system has been operating in space for nearly 8 years since launched on NASA's EOS Aura Spacecraft. The instrument is an infrared imaging fourier transform spectrometer with spectral coverage of 3.2 to 15.4 microns. The loop heat pipe (LHP) based heat rejection system manages all of the instrument components waste heat including the two mechanical cryocoolers and their drive electronics. Five propylene LHPs collect and transport the instrument waste heat to the near room temperature nadir viewing radiators. During the early months of the mission, ice contamination of the cryogenic surfaces including the focal planes led to increased cryocooler loads and the need for periodic decontamination cycles. Focal plane decontamination cycles require power cycling both cryocoolers which also requires the two cryocooler LHPs to turn off and on during each cycle. To date, the cryocooler LHPs have undergone 24 start-ups in orbit successfully. This paper reports on the TES cryocooler loop heat pipe based heat rejection system performance. After a brief overview of the instrument thermal design, the paper presents detailed data on the highly successful space operation of the loop heat pipes since instrument turn-on in 2004. The data shows that the steady-state and transient operation of the LHPs has not changed since 2004 and shows consistent and predictable performance. The LHP based heat rejection system has provided a nearly constant heat rejection heat sink for all of its equipment which has led to exceptional overall instrument performance with world class science.
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Functional Loop Dynamics of the Streptavidin-Biotin Complex
Song, Jianing; Li, Yongle; Ji, Changge; Zhang, John Z. H.
2015-01-01
Accelerated molecular dynamics (aMD) simulation is employed to study the functional dynamics of the flexible loop3-4 in the strong-binding streptavidin-biotin complex system. Conventional molecular (cMD) simulation is also performed for comparison. The present study reveals the following important properties of the loop dynamics: (1) The transition of loop3-4 from open to closed state is observed in 200 ns aMD simulation. (2) In the absence of biotin binding, the open-state streptavidin is more stable, which is consistent with experimental evidences. The free energy (ΔG) difference is about 5 kcal/mol between two states. But with biotin binding, the closed state is more stable due to electrostatic and hydrophobic interactions between the loop3-4 and biotin. (3) The closure of loop3-4 is concerted to the stable binding of biotin to streptavidin. When the loop3-4 is in its open-state, biotin moves out of the binding pocket, indicating that the interactions between the loop3-4 and biotin are essential in trapping biotin in the binding pocket. (4) In the tetrameric streptavidin system, the conformational change of the loop3-4 in each monomer is independent of each other. That is, there is no cooperative binding for biotin bound to the four subunits of the tetramer. PMID:25601277
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Damped transverse oscillations of interacting coronal loops
NASA Astrophysics Data System (ADS)
Soler, Roberto; Luna, Manuel
2015-10-01
Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can be used to probe the physical conditions of the coronal medium. Some observations suggest that interaction between neighboring oscillating loops in an active region may be important and can modify the properties of the oscillations. Here we theoretically investigate resonantly damped transverse oscillations of interacting nonuniform coronal loops. We provide a semi-analytic method, based on the T-matrix theory of scattering, to compute the frequencies and damping rates of collective oscillations of an arbitrary configuration of parallel cylindrical loops. The effect of resonant damping is included in the T-matrix scheme in the thin boundary approximation. Analytic and numerical results in the specific case of two interacting loops are given as an application.
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Perception as a closed-loop convergence process
Ahissar, Ehud; Assa, Eldad
2016-01-01
Perception of external objects involves sensory acquisition via the relevant sensory organs. A widely-accepted assumption is that the sensory organ is the first station in a serial chain of processing circuits leading to an internal circuit in which a percept emerges. This open-loop scheme, in which the interaction between the sensory organ and the environment is not affected by its concurrent downstream neuronal processing, is strongly challenged by behavioral and anatomical data. We present here a hypothesis in which the perception of external objects is a closed-loop dynamical process encompassing loops that integrate the organism and its environment and converging towards organism-environment steady-states. We discuss the consistency of closed-loop perception (CLP) with empirical data and show that it can be synthesized in a robotic setup. Testable predictions are proposed for empirical distinction between open and closed loop schemes of perception. DOI: http://dx.doi.org/10.7554/eLife.12830.001 PMID:27159238
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A comparative approach to closed-loop computation.
Roth, E; Sponberg, S; Cowan, N J
2014-04-01
Neural computation is inescapably closed-loop: the nervous system processes sensory signals to shape motor output, and motor output consequently shapes sensory input. Technological advances have enabled neuroscientists to close, open, and alter feedback loops in a wide range of experimental preparations. The experimental capability of manipulating the topology-that is, how information can flow between subsystems-provides new opportunities to understand the mechanisms and computations underlying behavior. These experiments encompass a spectrum of approaches from fully open-loop, restrained preparations to the fully closed-loop character of free behavior. Control theory and system identification provide a clear computational framework for relating these experimental approaches. We describe recent progress and new directions for translating experiments at one level in this spectrum to predictions at another level. Operating across this spectrum can reveal new understanding of how low-level neural mechanisms relate to high-level function during closed-loop behavior. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Two AFC Loops For Low CNR And High Dynamics
NASA Technical Reports Server (NTRS)
Hinedi, Sami M.; Aguirre, Sergio
1992-01-01
Two alternative digital automatic-frequency-control (AFC) loops proposed to acquire (or reacquire) and track frequency of received carrier radio signal. Intended for use where carrier-to-noise ratios (CNR's) low and carrier frequency characterized by high Doppler shift and Doppler rate because of high relative speed and acceleration, respectively, between transmitter and receiver. Either AFC loops used in place of phase-locked loop. New loop concepts integrate ideas from classical spectrum-estimation, digital-phase-locked-loop, and Kalman-Filter theories.
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Development of a hardware-in-loop attitude control simulator for a CubeSat satellite
NASA Astrophysics Data System (ADS)
Tapsawat, Wittawat; Sangpet, Teerawat; Kuntanapreeda, Suwat
2018-01-01
Attitude control is an important part in satellite on-orbit operation. It greatly affects the performance of satellites. Testing of an attitude determination and control subsystem (ADCS) is very challenging since it might require attitude dynamics and space environment in the orbit. This paper develops a low-cost hardware-in-loop (HIL) simulator for testing an ADCS of a CubeSat satellite. The simulator consists of a numerical simulation part, a hardware part, and a HIL interface hardware unit. The numerical simulation part includes orbital dynamics, attitude dynamics and Earth’s magnetic field. The hardware part is the real ADCS board of the satellite. The simulation part outputs satellite’s angular velocity and geomagnetic field information to the HIL interface hardware. Then, based on this information, the HIL interface hardware generates I2C signals mimicking the signals of the on-board rate-gyros and magnetometers and consequently outputs the signals to the ADCS board. The ADCS board reads the rate-gyro and magnetometer signals, calculates control signals, and drives the attitude actuators which are three magnetic torquers (MTQs). The responses of the MTQs sensed by a separated magnetometer are feedback to the numerical simulation part completing the HIL simulation loop. Experimental studies are conducted to demonstrate the feasibility and effectiveness of the simulator.
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Schwaiberger, David; Pickerodt, Philipp A; Pomprapa, Anake; Tjarks, Onno; Kork, Felix; Boemke, Willehad; Francis, Roland C E; Leonhardt, Steffen; Lachmann, Burkhard
2018-06-01
Adherence to low tidal volume (V T ) ventilation and selected positive end-expiratory pressures are low during mechanical ventilation for treatment of the acute respiratory distress syndrome. Using a pig model of severe lung injury, we tested the feasibility and physiological responses to a novel fully closed-loop mechanical ventilation algorithm based on the "open lung" concept. Lung injury was induced by surfactant washout in pigs (n = 8). Animals were ventilated following the principles of the "open lung approach" (OLA) using a fully closed-loop physiological feedback algorithm for mechanical ventilation. Standard gas exchange, respiratory- and hemodynamic parameters were measured. Electrical impedance tomography was used to quantify regional ventilation distribution during mechanical ventilation. Automatized mechanical ventilation provided strict adherence to low V T -ventilation for 6 h in severely lung injured pigs. Using the "open lung" approach, tidal volume delivery required low lung distending pressures, increased recruitment and ventilation of dorsal lung regions and improved arterial blood oxygenation. Physiological feedback closed-loop mechanical ventilation according to the principles of the open lung concept is feasible and provides low tidal volume ventilation without human intervention. Of importance, the "open lung approach"-ventilation improved gas exchange and reduced lung driving pressures by opening atelectasis and shifting of ventilation to dorsal lung regions.
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Shortening a loop can increase protein native state entropy.
Gavrilov, Yulian; Dagan, Shlomi; Levy, Yaakov
2015-12-01
Protein loops are essential structural elements that influence not only function but also protein stability and folding rates. It was recently reported that shortening a loop in the AcP protein may increase its native state conformational entropy. This effect on the entropy of the folded state can be much larger than the lower entropic penalty of ordering a shorter loop upon folding, and can therefore result in a more pronounced stabilization than predicted by polymer model for loop closure entropy. In this study, which aims at generalizing the effect of loop length shortening on native state dynamics, we use all-atom molecular dynamics simulations to study how gradual shortening a very long or solvent-exposed loop region in four different proteins can affect their stability. For two proteins, AcP and Ubc7, we show an increase in native state entropy in addition to the known effect of the loop length on the unfolded state entropy. However, for two permutants of SH3 domain, shortening a loop results only with the expected change in the entropy of the unfolded state, which nicely reproduces the observed experimental stabilization. Here, we show that an increase in the native state entropy following loop shortening is not unique to the AcP protein, yet nor is it a general rule that applies to all proteins following the truncation of any loop. This modification of the loop length on the folded state and on the unfolded state may result with a greater effect on protein stability. © 2015 Wiley Periodicals, Inc.
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MULTI-STRAND CORONAL LOOP MODEL AND FILTER-RATIO ANALYSIS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bourouaine, Sofiane; Marsch, Eckart, E-mail: bourouaine@mps.mpg.d
2010-01-10
We model a coronal loop as a bundle of seven separate strands or filaments. Each of the loop strands used in this model can independently be heated (near their left footpoints) by Alfven/ion-cyclotron waves via wave-particle interactions. The Alfven waves are assumed to penetrate the strands from their footpoints, at which we consider different wave energy inputs. As a result, the loop strands can have different heating profiles, and the differential heating can lead to a varying cross-field temperature in the total coronal loop. The simulation of Transition Region and Coronal Explorer (TRACE) observations by means of this loop modelmore » implies two uniform temperatures along the loop length, one inferred from the 171:195 filter ratio and the other from the 171:284 ratio. The reproduced flat temperature profiles are consistent with those inferred from the observed extreme-ultraviolet coronal loops. According to our model, the flat temperature profile is a consequence of the coronal loop consisting of filaments, which have different temperatures but almost similar emission measures in the cross-field direction. Furthermore, when we assume certain errors in the simulated loop emissions (e.g., due to photometric uncertainties in the TRACE filters) and use the triple-filter analysis, our simulated loop conditions become consistent with those of an isothermal plasma. This implies that the use of TRACE or EUV Imaging Telescope triple filters for observation of a warm coronal loop may not help in determining whether the cross-field isothermal assumption is satisfied or not.« less
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The IL-6/JAK/Stat3 feed-forward loop drives tumorigenesis and metastasis.
Chang, Qing; Bournazou, Eirini; Sansone, Pasquale; Berishaj, Marjan; Gao, Sizhi Paul; Daly, Laura; Wels, Jared; Theilen, Till; Granitto, Selena; Zhang, Xinmin; Cotari, Jesse; Alpaugh, Mary L; de Stanchina, Elisa; Manova, Katia; Li, Ming; Bonafe, Massimiliano; Ceccarelli, Claudio; Taffurelli, Mario; Santini, Donatella; Altan-Bonnet, Gregoire; Kaplan, Rosandra; Norton, Larry; Nishimoto, Norihiro; Huszar, Dennis; Lyden, David; Bromberg, Jacqueline
2013-07-01
We have investigated the importance of interleukin-6 (IL-6) in promoting tumor growth and metastasis. In human primary breast cancers, increased levels of IL-6 were found at the tumor leading edge and positively correlated with advanced stage, suggesting a mechanistic link between tumor cell production of IL-6 and invasion. In support of this hypothesis, we showed that the IL-6/Janus kinase (JAK)/signal transducer and activator of transcription 3 (Stat3) pathway drives tumor progression through the stroma and metastatic niche. Overexpression of IL-6 in tumor cell lines promoted myeloid cell recruitment, angiogenesis, and induced metastases. We demonstrated the therapeutic potential of interrupting this pathway with IL-6 receptor blockade or by inhibiting its downstream effectors JAK1/2 or Stat3. These clinically relevant interventions did not inhibit tumor cell proliferation in vitro but had profound effects in vivo on tumor progression, interfering broadly with tumor-supportive stromal functions, including angiogenesis, fibroblast infiltration, and myeloid suppressor cell recruitment in both the tumor and pre-metastatic niche. This study provides the first evidence for IL-6 expression at the leading edge of invasive human breast tumors and demonstrates mechanistically that IL-6/JAK/Stat3 signaling plays a critical and pharmacologically targetable role in orchestrating the composition of the tumor microenvironment that promotes growth, invasion, and metastasis.
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Man-in-the-control-loop simulation of manipulators
NASA Technical Reports Server (NTRS)
Chang, J. L.; Lin, Tsung-Chieh; Yae, K. Harold
1989-01-01
A method to achieve man-in-the-control-loop simulation is presented. Emerging real-time dynamics simulation suggests a potential for creating an interactive design workstation with a human operator in the control loop. The recursive formulation for multibody dynamics simulation is studied to determine requirements for man-in-the-control-loop simulation. High speed computer graphics techniques provides realistic visual cues for the simulator. Backhoe and robot arm simulations are implemented to demonstrate the capability of man-in-the-control-loop simulation.
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On the nature of fast sausage waves in coronal loops
NASA Astrophysics Data System (ADS)
Bahari, Karam
2018-05-01
The effect of the parameters of coronal loops on the nature of fast sausage waves are investigated. To do this three models of the coronal loop considered, a simple loop model, a current-carrying loop model and a model with radially structured density called "Inner μ" profile. For all the models the Magnetohydrodynamic (MHD) equations solved analytically in the linear approximation and the restoring forces of oscillations obtained. The ratio of the magnetic tension force to the pressure gradient force obtained as a function of the distance from the axis of the loop. In the simple loop model for all values of the loop parameters the fast sausages wave have a mixed nature of Alfvénic and fast MHD waves, in the current-carrying loop model with thick annulus and low density contrast the fast sausage waves can be considered as purely Alfvénic wave in the core region of the loop, and in the "Inner μ" profile for each set of the parameters of the loop the wave can be considered as a purely Alfvénic wave in some regions of the loop.
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Kostermans, Evelien; Stoolmiller, Mike; de Leeuw, Rebecca N H; Engels, Rutger C M E; Sargent, James D
2014-01-01
We examine the association between exposure to depictions of reckless driving in movies and unsafe driving, modeling inattentive and reckless driving as separate outcomes. Data were obtained by telephone from 1,630 US adolescents aged 10 to 14 years at baseline who were drivers at a survey 6 years later. Exposure to movie reckless driving was measured based on movies seen from a randomly selected list of 50 movie titles that had been content coded for reckless driving among characters. Associations were tested with inattentive and reckless driving behaviors in the subsequent survey-controlling for baseline age, sex, socioeconomic status, parental education, school performance, extracurricular activities, daily television and video/computer game exposure, number of movies watched per week, self-regulation and sensation seeking. Exposure to movie reckless driving was common, with approximately 10% of movie characters having driven recklessly. Confirmatory factor analysis revealed a significant distinction between items tapping reckless and inattentive driving at the 6th wave. Age and exposure to movie reckless driving at baseline were directly associated with wave-6 reckless (but not inattentive) driving. Additionally, growth in sensation seeking mediated a prospective relation between the total number of movies watched per week at baseline and reckless driving, independent of exposure to movie reckless driving. Males and high sensation seekers reported lower seatbelt usage and more reckless driving, whereas lower self-regulation predicted inattentive driving. In this study, exposure to movie reckless driving during early adolescence predicted adolescents' reckless driving, suggesting a direct modeling effect. Other aspects of movies were also associated with reckless driving, with that association mediated through growth in sensation seeking. Predictors of reckless driving were different from predictors of inattentive driving, with lower self-regulation associated
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Kostermans, Evelien; Stoolmiller, Mike; de Leeuw, Rebecca N. H.; Engels, Rutger C. M. E.; Sargent, James D.
2014-01-01
Objective We examine the association between exposure to depictions of reckless driving in movies and unsafe driving, modeling inattentive and reckless driving as separate outcomes. Methods Data were obtained by telephone from 1,630 US adolescents aged 10 to 14 years at baseline who were drivers at a survey 6 years later. Exposure to movie reckless driving was measured based on movies seen from a randomly selected list of 50 movie titles that had been content coded for reckless driving among characters. Associations were tested with inattentive and reckless driving behaviors in the subsequent survey–controlling for baseline age, sex, socioeconomic status, parental education, school performance, extracurricular activities, daily television and video/computer game exposure, number of movies watched per week, self-regulation and sensation seeking. Results Exposure to movie reckless driving was common, with approximately 10% of movie characters having driven recklessly. Confirmatory factor analysis revealed a significant distinction between items tapping reckless and inattentive driving at the 6th wave. Age and exposure to movie reckless driving at baseline were directly associated with wave-6 reckless (but not inattentive) driving. Additionally, growth in sensation seeking mediated a prospective relation between the total number of movies watched per week at baseline and reckless driving, independent of exposure to movie reckless driving. Males and high sensation seekers reported lower seatbelt usage and more reckless driving, whereas lower self-regulation predicted inattentive driving. Discussion In this study, exposure to movie reckless driving during early adolescence predicted adolescents’ reckless driving, suggesting a direct modeling effect. Other aspects of movies were also associated with reckless driving, with that association mediated through growth in sensation seeking. Predictors of reckless driving were different from predictors of inattentive driving
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Spring control of wire harness loops
NASA Technical Reports Server (NTRS)
Curcio, P. J.
1979-01-01
Negator spring control guides wire harness between movable and fixed structure. It prevents electrical wire harness loop from jamming or being severed as wire moves in response to changes in position of aircraft rudder. Spring-loaded coiled cable controls wire loop regardless of rudder movement.
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Orlowska-Kowalska, Teresa; Kaminski, Marcin
2014-01-01
The paper deals with the implementation of optimized neural networks (NNs) for state variable estimation of the drive system with an elastic joint. The signals estimated by NNs are used in the control structure with a state-space controller and additional feedbacks from the shaft torque and the load speed. High estimation quality is very important for the correct operation of a closed-loop system. The precision of state variables estimation depends on the generalization properties of NNs. A short review of optimization methods of the NN is presented. Two techniques typical for regularization and pruning methods are described and tested in detail: the Bayesian regularization and the Optimal Brain Damage methods. Simulation results show good precision of both optimized neural estimators for a wide range of changes of the load speed and the load torque, not only for nominal but also changed parameters of the drive system. The simulation results are verified in a laboratory setup.
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NASA Technical Reports Server (NTRS)
Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)
2011-01-01
A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.
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Loop corrections to primordial non-Gaussianity
NASA Astrophysics Data System (ADS)
Boran, Sibel; Kahya, E. O.
2018-02-01
We discuss quantum gravitational loop effects to observable quantities such as curvature power spectrum and primordial non-Gaussianity of cosmic microwave background (CMB) radiation. We first review the previously shown case where one gets a time dependence for zeta-zeta correlator due to loop corrections. Then we investigate the effect of loop corrections to primordial non-Gaussianity of CMB. We conclude that, even with a single scalar inflaton, one might get a huge value for non-Gaussianity which would exceed the observed value by at least 30 orders of magnitude. Finally we discuss the consequences of this result for scalar driven inflationary models.
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Genome Organization Drives Chromosome Fragility.
Canela, Andres; Maman, Yaakov; Jung, Seolkyoung; Wong, Nancy; Callen, Elsa; Day, Amanda; Kieffer-Kwon, Kyong-Rim; Pekowska, Aleksandra; Zhang, Hongliang; Rao, Suhas S P; Huang, Su-Chen; Mckinnon, Peter J; Aplan, Peter D; Pommier, Yves; Aiden, Erez Lieberman; Casellas, Rafael; Nussenzweig, André
2017-07-27
In this study, we show that evolutionarily conserved chromosome loop anchors bound by CCCTC-binding factor (CTCF) and cohesin are vulnerable to DNA double strand breaks (DSBs) mediated by topoisomerase 2B (TOP2B). Polymorphisms in the genome that redistribute CTCF/cohesin occupancy rewire DNA cleavage sites to novel loop anchors. While transcription- and replication-coupled genomic rearrangements have been well documented, we demonstrate that DSBs formed at loop anchors are largely transcription-, replication-, and cell-type-independent. DSBs are continuously formed throughout interphase, are enriched on both sides of strong topological domain borders, and frequently occur at breakpoint clusters commonly translocated in cancer. Thus, loop anchors serve as fragile sites that generate DSBs and chromosomal rearrangements. VIDEO ABSTRACT. Published by Elsevier Inc.
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Hostility, driving anger, and dangerous driving: the emerging role of hemispheric preference.
Gidron, Yori; Gaygısız, Esma; Lajunen, Timo
2014-12-01
Various studies have implicated psychosocial variables (e.g., hostility) in risk of dangerous driving and traffic accidents. However, whether these variables are related to more basic neurobiological factors, and whether such associations have implications for the modification of psychosocial risk factors in the context of driving, have not been examined in depth. This study examined the relationship between hemispheric preference (HP), hostility and self-reported dangerous driving, and the ability to affect driving anger via hemisphere activating cognitive exercises (HACE). In Study 1, 254 Turkish students completed questionnaires of hostility, HP and driving behavior. In Study 2, we conducted a "proof of concept" experimental study, and tested effects of left, right and neutral HACE on driving anger, by exposing N=650 Turkish students to written scenarios including either logical (left hemisphere), visuo-spatial (right hemisphere) or "mild doses" of both types of contents (control). In Study 1, left-HP was associated with higher hostility and with more dangerous driving, and hostility mediated the relationship between L-HP and reported driving behavior. In Study 2, only right-HACE led to immediate significant reductions in self-reported driving anger. Left-HP is related to hostility and to dangerous driving, and it may be possible to partly reduce driving anger by right-HACE. Future studies must replicate these findings with objective measures, more enduring interventions and longer follow-ups. Copyright © 2014. Published by Elsevier Ltd.
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System identification from closed-loop data with known output feedback dynamics
NASA Technical Reports Server (NTRS)
Phan, Minh; Juang, Jer-Nan; Horta, Lucas G.; Longman, Richard W.
1992-01-01
This paper presents a procedure to identify the open loop systems when it is operating under closed loop conditions. First, closed loop excitation data are used to compute the system open loop and closed loop Markov parameters. The Markov parameters, which are the pulse response samples, are then used to compute a state space representation of the open loop system. Two closed loop configurations are considered in this paper. The closed loop system can have either a linear output feedback controller or a dynamic output feedback controller. Numerical examples are provided to illustrate the proposed closed loop identification method.
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Radiation Enhanced Absorption of Frank Loops by Nanovoids in Cu
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chen, Youxing; Zhang, Xinghang; Wang, Jian
Neutron and heavy ion irradiation generally induces voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage [Y. Chen et al., Nat. Commun. 6:7036 (2015)]. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacentmore » to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop-nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.« less
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Radiation Enhanced Absorption of Frank Loops by Nanovoids in Cu
Chen, Youxing; Zhang, Xinghang; Wang, Jian
2016-11-01
Neutron and heavy ion irradiation generally induces voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage [Y. Chen et al., Nat. Commun. 6:7036 (2015)]. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacentmore » to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop-nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.« less
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Smith, Jordan; Mansfield, Neil; Gyi, Diane; Pagett, Mark; Bateman, Bob
2015-07-01
The primary purposes of a vehicle driver's seat, is to allow them to complete the driving task comfortably and safely. Within each class of vehicle (e.g. passenger, commercial, industrial, agricultural), there is an expected driving position to which a vehicle cabin is designed. This paper reports a study that compares two driving positions, in relation to Light Commercial Vehicles (LCVs), in terms of driver performance and driver discomfort. In the 'elevated' driving position, the seat is higher than usually used in road vehicles; this is compared to a standard driving position replicating the layout for a commercially available vehicle. It is shown that for a sample of 12 drivers, the elevated position did not, in general, show more discomfort than the standard position over a 60 min driving simulation, although discomfort increased with duration. There were no adverse effects shown for emergency stop reaction time or for driver headway for the elevated posture compared to the standard posture. The only body part that showed greater discomfort for the elevated posture compared to the standard posture was the right ankle. A second experiment confirmed that for 12 subjects, a higher pedal stiffness eliminated the ankle discomfort problem. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.
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Browns Ferry-1 single-loop operation tests
DOE Office of Scientific and Technical Information (OSTI.GOV)
March-Leuba, J.; Wood, R.T.; Otaduy, P.J.
1985-09-01
This report documents the results of the stability tests performed on February 9, 1985, at the Browns Ferry Nuclear Power Plant Unit 1 under single-loop operating conditions. The observed increase in neutron noise during single-loop operation is solely due to an increase in flow noise. The Browns Ferry-1 reactor has been found to be stable in all modes of operation attained during the present tests. The most unstable test plateau corresponded to minimum recirculation pump speed in single-loop operation (test BFTP3). This operating condition had the minimum flow and maximum power-to-flow ratio. The estimated decay ratio in this plateau ismore » 0.53. The decay ratio decreased as the flow was increased during single-loop operation (down to 0.34 for test plateau BFTP6). This observation implies that the core-wide reactor stability follows the same trends in single-loop as it does in two-loop operation. Finally, no local or higher mode instabilities were found in the data taken from local power range monitors. The decay ratios estimated from the local power range monitors were not significantly different from those estimated from the average power range monitors.« less
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Paës, Gabriel; Cortés, Juan; Siméon, Thierry; O'Donohue, Michael J.; Tran, Vinh
2012-01-01
Dynamics is a key feature of enzyme catalysis. Unfortunately, current experimental and computational techniques do not yet provide a comprehensive understanding and description of functional macromolecular motions. In this work, we have extended a novel computational technique, which combines molecular modeling methods and robotics algorithms, to investigate functional motions of protein loops. This new approach has been applied to study the functional importance of the so-called thumb-loop in the glycoside hydrolase family 11 xylanase from Thermobacillus xylanilyticus (Tx-xyl). The results obtained provide new insight into the role of the loop in the glycosylation/deglycosylation catalytic cycle, and underline the key importance of the nature of the residue located at the tip of the thumb-loop. The effect of mutations predicted in silico has been validated by in vitro site-directed mutagenesis experiments. Overall, we propose a comprehensive model of Tx-xyl catalysis in terms of substrate and product dynamics by identifying the action of the thumb-loop motion during catalysis. PMID:24688637
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Transequatorial loops interconnecting McMath regions 12472 and 12474
NASA Technical Reports Server (NTRS)
Svestka, Z.; Krieger, A. S.; Chase, R. C.; Howard, R.
1977-01-01
The paper reviews the life history of one transequatorial loop in a system observed in soft X-rays for at least 1.5 days and which interconnected a newly born active region with an old region. The birth of the selected loop is discussed along with properties of the interconnected active regions, sharpening and brightening of the loop, decay of the loop system, and physical relations between the interconnected regions. It is concluded that: (1) the loop was most probably born via reconnection of magnetic-field lines extending from the two active regions toward the equator, which occurred later than 33 hr after the younger region was born; (2) the fully developed interconnection was composed of several loops, all of which appeared to be rooted in a spotless magnetic hill of preceding northern polarity but were spread over two separate spotty regions of southern polarity in the magnetically complex new region; (3) the loop electron temperature increased from 2.1 million to 3.1 million K in one to three hours when the loop system brightened; and (4) the loops became twisted during the brightening, possibly due to their rise in the corona while remaining rooted in moving magnetic features in the younger region.
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Proprioceptive coupling within motor neurons drives C. elegans forward locomotion
Wen, Quan; Po, Michelle; Hulme, Elizabeth; Chen, Sway; Liu, Xinyu; Kwok, Sen Wai; Gershow, Marc; Leifer, Andrew M; Butler, Victoria; Fang-Yen, Christopher; Kawano, Taizo; Schafer, William R; Whitesides, George
2012-01-01
Summary Locomotion requires coordinated motor activity throughout an animal’s body. In both vertebrates and invertebrates, chains of coupled Central Pattern Generators (CPGs) are commonly evoked to explain local rhythmic behaviors. In C. elegans, we report that proprioception within the motor circuit is responsible for propagating and coordinating rhythmic undulatory waves from head to tail during forward movement. Proprioceptive coupling between adjacent body regions transduces rhythmic movement initiated near the head into bending waves driven along the body by a chain of reflexes. Using optogenetics and calcium imaging to manipulate and monitor motor circuit activity of moving C. elegans held in microfluidic devices, we found that the B-type cholinergic motor neurons transduce the proprioceptive signal. In C. elegans, a sensorimotor feedback loop operating within a specific type of motor neuron both drives and organizes body movement. PMID:23177960
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Harwell high pressure heat transfer loop
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, A.W.; Keeys, R.K.F.
1967-12-15
A detailed description is presented of the Harwell (Chemical Engineering and Process Technology Division) high pressure, steam-water heat transfer loop; this description is aimed at supplementing the information given in reports on individual experiments. The operating instructions for the loop are given in an appendix. (auth)
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... Alcohol Club Drugs Cocaine Fentanyl Hallucinogens Inhalants Heroin Marijuana MDMA (Ecstasy/Molly) Methamphetamine Opioids Over-the-Counter ... in the past year. Middle Figure: Driving after marijuana use is more common than driving after alcohol ...
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Dynamical behaviour in coronal loops
NASA Technical Reports Server (NTRS)
Haisch, Bernhard M.
1986-01-01
Rapid variability has been found in two active region coronal loops observed by the X-ray Polychromator (XRP) and the Hard X-ray Imaging Spectrometer (HXIS) onboard the Solar Maximum Mission (SMM). There appear to be surprisingly few observations of the short-time scale behavior of hot loops, and the evidence presented herein lends support to the hypothesis that coronal heating may be impulsive and driven by flaring.
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Dynamical behaviour in coronal loops
NASA Astrophysics Data System (ADS)
Haisch, Bernhard M.
Rapid variability has been found in two active region coronal loops observed by the X-ray Polychromator (XRP) and the Hard X-ray Imaging Spectrometer (HXIS) onboard the Solar Maximum Mission (SMM). There appear to be surprisingly few observations of the short-time scale behavior of hot loops, and the evidence presented herein lends support to the hypothesis that coronal heating may be impulsive and driven by flaring.
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Assessment of driving-related performance in chronic whiplash using an advanced driving simulator.
Takasaki, Hiroshi; Treleaven, Julia; Johnston, Venerina; Rakotonirainy, Andry; Haines, Andrew; Jull, Gwendolen
2013-11-01
Driving is often nominated as problematic by individuals with chronic whiplash associated disorders (WAD), yet driving-related performance has not been evaluated objectively. The purpose of this study was to test driving-related performance in persons with chronic WAD against healthy controls of similar age, gender and driving experience to determine if driving-related performance in the WAD group was sufficiently impaired to recommend fitness to drive assessment. Driving-related performance was assessed using an advanced driving simulator during three driving scenarios; freeway, residential and a central business district (CBD). Total driving duration was approximately 15min. Five driving tasks which could cause a collision (critical events) were included in the scenarios. In addition, the effect of divided attention (identify red dots projected onto side or rear view mirrors) was assessed three times in each scenario. Driving performance was measured using the simulator performance index (SPI) which is calculated from 12 measures. z-Scores for all SPI measures were calculated for each WAD subject based on mean values of the control subjects. The z-scores were then averaged for the WAD group. A z-score of ≤-2 indicated a driving failing grade in the simulator. The number of collisions over the five critical events was compared between the WAD and control groups as was reaction time and missed response ratio in identifying the red dots. Seventeen WAD and 26 control subjects commenced the driving assessment. Demographic data were comparable between the groups. All subjects completed the freeway scenario but four withdrew during the residential and eight during the CBD scenario because of motion sickness. All scenarios were completed by 14 WAD and 17 control subjects. Mean z-scores for the SPI over the three scenarios was statistically lower in the WAD group (-0.3±0.3; P<0.05) but the score was not below the cut-off point for safe driving. There were no
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On the Loop Current Penetration into the Gulf of Mexico
NASA Astrophysics Data System (ADS)
Weisberg, Robert H.; Liu, Yonggang
2017-12-01
The Gulf of Mexico Loop Current generally intrudes some distance into the Gulf of Mexico before shedding an anticyclonic eddy and retreating back to its more direct entry to exit pathway. The control of this aperiodic process remains only partially known. Here we describe the evolution of the Loop Current throughout the era of satellite altimetry, and offer a mechanistic hypothesis on Loop Current intrusion. As a complement to the known effects of Loop Current forcing on the west Florida shelf circulation, we argue that the west Florida shelf, in turn, impacts the Loop Current evolution. A Self-Organizing Map analysis shows that anomalous northward penetrations of the Loop Current into the Gulf of Mexico occur when the eastern side of Loop Current is positioned west from the southwest corner of the west Florida shelf, whereas the more direct inflow to outflow route occurs when the eastern side of the Loop Current comes in contact with the southwest corner of the west Florida shelf. In essence, we argue that the west Florida shelf anchors the Loop Current in its direct path configuration and that farther northward penetration into the Gulf of Mexico occurs when such anchoring is released. To test of this hypothesis heuristically, we estimate that the dissipation and buoyancy work due to known Loop Current forcing of the west Florida shelf circulation (when in contact with the southwest corner) may exceed the pressure work required for the Loop Current to advance against the ambient Gulf of Mexico fluid.
Plain Language SummaryThe Gulf of Mexico <span class="hlt">Loop</span> Current may intrude far into the Gulf of Mexico or take a more direct entry to exit pathway. Such <span class="hlt">Loop</span> Current behaviors are described using remote observations by satellites, and a heuristic hypothesis on the control of <span class="hlt">Loop</span> Current intrusion is presented. We argue that energy dissipation and buoyancy work by the west Florida shelf circulation, when the <span class="hlt">Loop</span> Current contacts</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27328019','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27328019"><span>The effects of cognitively demanding dual-task <span class="hlt">driving</span> condition on elderly people's <span class="hlt">driving</span> performance; Real <span class="hlt">driving</span> monitoring.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ebnali, Mahdi; Ahmadnezhad, Pedram; Shateri, Alireza; Mazloumi, Adel; Ebnali Heidari, Majid; Nazeri, Ahmad Reza</p> <p>2016-09-01</p> <p>Using in-vehicle audio technologies such as audio systems and voice messages is regarded as a common secondary task. Such tasks, known as the sources of non-visual distraction, affect the <span class="hlt">driving</span> performance. Given the elderly drivers' cognitive limitations, <span class="hlt">driving</span> can be even more challenging to drivers. The current study examined how listening to economic news, as a cognitively demanding secondary task, affects elderly subjects' <span class="hlt">driving</span> performance and whether their comprehension accuracy is associated with these effects. Participants of the study (N=22) drove in a real condition with and without listening to economic news. Measurements included <span class="hlt">driving</span> performance (speed control, forward crash risk, and lateral lane position) and task performance (comprehension accuracy). The mean <span class="hlt">driving</span> speed, duration of <span class="hlt">driving</span> in unsafe zones and numbers of overtaking decreased significantly when drivers were engaged in the dual-task condition. Moreover, the cognitive secondary task led to a higher speed variability. Our results demonstrate that there was not a significant relationship between the lane changes and the activity of listening to economic news. However, a meaningful difference was observed between general comprehension and deep comprehension on the one hand and <span class="hlt">driving</span> performance on the other. Another aspect of our study concerning the drivers' ages and their comprehension revealed a significant relationship between age above 75 and comprehension level. Drivers aging 75 and older showed a lower level of deep comprehension. Our study demonstrates that elderly drivers compensated <span class="hlt">driving</span> performance with safety margin adoption while they were cognitively engaged. In this condition, however, maintaining speed proved more demanding for drivers aging 75 and older. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5257216','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5257216"><span><span class="hlt">Driving</span> and dementia</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lee, Linda; Molnar, Frank</p> <p>2017-01-01</p> <p>Abstract Objective To provide primary care physicians with an approach to <span class="hlt">driving</span> safety concerns when older persons present with memory difficulties. Sources of information The approach is based on an accredited memory clinic training program developed by the Centre for Family Medicine Primary Care Collaborative Memory Clinic. Main message One of the most challenging aspects of dementia care is the assessment of <span class="hlt">driving</span> safety. Drivers with dementia are at higher risk of motor vehicle collisions, yet many drivers with mild dementia might be safely able to continue <span class="hlt">driving</span> for several years. Because safe <span class="hlt">driving</span> is dependent on multiple cognitive and functional skills, clinicians should carefully consider many factors when determining if cognitive concerns affect <span class="hlt">driving</span> safety. Specific findings on corroborated history and office-based cognitive testing might aid in the physician’s decisions to refer for comprehensive on-road <span class="hlt">driving</span> evaluation and whether to notify transportation authorities in accordance with provincial reporting requirements. Sensitive communication and a person-centred approach are essential. Conclusion Primary care physicians must consider many factors when determining if cognitive concerns might affect <span class="hlt">driving</span> safety in older drivers. PMID:28115437</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.523a2061B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.523a2061B"><span>Multi-<span class="hlt">loop</span> Integrand Reduction with Computational Algebraic Geometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Badger, Simon; Frellesvig, Hjalte; Zhang, Yang</p> <p>2014-06-01</p> <p>We discuss recent progress in multi-<span class="hlt">loop</span> integrand reduction methods. Motivated by the possibility of an automated construction of multi-<span class="hlt">loop</span> amplitudes via generalized unitarity cuts we describe a procedure to obtain a general parameterisation of any multi-<span class="hlt">loop</span> integrand in a renormalizable gauge theory. The method relies on computational algebraic geometry techniques such as Gröbner bases and primary decomposition of ideals. We present some results for two and three <span class="hlt">loop</span> amplitudes obtained with the help of the MACAULAY2 computer algebra system and the Mathematica package BASISDET.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhDT.........6P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhDT.........6P"><span>Experiments Using Local Helicity Injectors in the Lower Divertor Region as the Majority Current <span class="hlt">Drive</span> in a Tokamak Plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perry, Justin M.</p> <p></p> <p>Local helicity injection (LHI) is a non-solenoidal current <span class="hlt">drive</span> capable of achieving high-Ip tokamak startup with a relatively compact and non-invasive array of current injectors in the plasma scrape-off layer. The choice of injector location within the edge region is flexible, but has a profound influence on the nature of the current <span class="hlt">drive</span> in LHI discharges. Past experiments on the Pegasus ST with injection on the low-field-side near the outboard midplane produced plasmas dominated by inductive <span class="hlt">drive</span> resulting primarily from plasma geometry evolution over the discharge. Recent experiments with injection on the high-field- side in the lower divertor region produce plasmas dominated by helicity injection current <span class="hlt">drive</span>, with relatively static plasma geometry, and thus negligible inductive <span class="hlt">drive</span>. Plasma current up to 200 kA is driven with helicity injection as the dominant current <span class="hlt">drive</span> using a pair of 4 cm2 area injectors sourcing 8 kA of total injected current. Steady sustainment with LHI current <span class="hlt">drive</span> alone is demonstrated, with 100 kA sustained for 18 ms. Maximum achievable plasma current is found to scale approximately linearly with a plasma-geometry- normalized form of the effective <span class="hlt">loop</span> voltage from LHI, Vnorm = AinjVinj/Rinj, where A inj is the total injector area, Vinj is the injector bias voltage, and Rinj is the major radius of the injectors. A newly-discovered MHD regime for LHI-driven plasmas is described, in which the large-amplitude n = 1 fluctuations at 20-50 kHz which are generally dominant during LHI are abruptly reduced by an order of magnitude on the outboard side. High frequency fluctuations ( f > 400 kHz) increase inside the plasma edge at the same time. This regime results in improved plasma current and pervasive changes to plasma behavior, and may suggest short wavelength turbulence as a current <span class="hlt">drive</span> mechanism during LHI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvD..97j5006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvD..97j5006C"><span>Universality hypothesis breakdown at one-<span class="hlt">loop</span> order</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carvalho, P. R. S.</p> <p>2018-05-01</p> <p>We probe the universality hypothesis by analytically computing the at least two-<span class="hlt">loop</span> corrections to the critical exponents for q -deformed O (N ) self-interacting λ ϕ4 scalar field theories through six distinct and independent field-theoretic renormalization group methods and ɛ -expansion techniques. We show that the effect of q deformation on the one-<span class="hlt">loop</span> corrections to the q -deformed critical exponents is null, so the universality hypothesis is broken down at this <span class="hlt">loop</span> order. Such an effect emerges only at the two-<span class="hlt">loop</span> and higher levels, and the validity of the universality hypothesis is restored. The q -deformed critical exponents obtained through the six methods are the same and, furthermore, reduce to their nondeformed values in the appropriated limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24792385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24792385"><span>Creating stable stem regions for <span class="hlt">loop</span> elongation in Fcabs - insights from combining yeast surface display, in silico <span class="hlt">loop</span> reconstruction and molecular dynamics simulations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hasenhindl, Christoph; Lai, Balder; Delgado, Javier; Traxlmayr, Michael W; Stadlmayr, Gerhard; Rüker, Florian; Serrano, Luis; Oostenbrink, Chris; Obinger, Christian</p> <p>2014-09-01</p> <p>Fcabs (Fc antigen binding) are crystallizable fragments of IgG where the C-terminal structural <span class="hlt">loops</span> of the CH3 domain are engineered for antigen binding. For the design of libraries it is beneficial to know positions that will permit <span class="hlt">loop</span> elongation to increase the potential interaction surface with antigen. However, the insertion of additional <span class="hlt">loop</span> residues might impair the immunoglobulin fold. In the present work we have probed whether stabilizing mutations flanking the randomized and elongated <span class="hlt">loop</span> region improve the quality of Fcab libraries. In detail, 13 libraries were constructed having the C-terminal part of the EF <span class="hlt">loop</span> randomized and carrying additional residues (1, 2, 3, 5 or 10, respectively) in the absence and presence of two flanking mutations. The latter have been demonstrated to increase the thermal stability of the CH3 domain of the respective solubly expressed proteins. Assessment of the stability of the libraries expressed on the surface of yeast cells by flow cytometry demonstrated that <span class="hlt">loop</span> elongation was considerably better tolerated in the stabilized libraries. By using in silico <span class="hlt">loop</span> reconstruction and mimicking randomization together with MD simulations the underlying molecular dynamics were investigated. In the presence of stabilizing stem residues the backbone flexibility of the engineered EF <span class="hlt">loop</span> as well as the fluctuation between its accessible conformations were decreased. In addition the CD <span class="hlt">loop</span> (but not the AB <span class="hlt">loop</span>) and most of the framework regions were rigidified. The obtained data are discussed with respect to the design of Fcabs and available data on the relation between flexibility and affinity of CDR <span class="hlt">loops</span> in Ig-like molecules. Copyright © 2014. Published by Elsevier B.V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSH31B2569Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSH31B2569Y"><span>Fine flow structures in the transition region small-scale <span class="hlt">loops</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, L.; Peter, H.; He, J.; Wei, Y.</p> <p>2016-12-01</p> <p>The observation and model have suggested that the transition region EUV emission from the quiet sun region is contributed by very small scale <span class="hlt">loops</span> which have not been resolved. Recently, the observation from IRIS has revealed that this kind of small scale <span class="hlt">loops</span>. Based on the high resolution spectral and imaging observation from IRIS, much more detail work needs to be done to reveal the fine flow features in this kind of <span class="hlt">loop</span> to help us understand the <span class="hlt">loop</span> heating. Here, we present a detail statistical study of the spatial and temporal evolution of Si IV line profiles of small scale <span class="hlt">loops</span> and report the spectral features: there is a transition from blue (red) wing enhancement dominant to red (blue) wing enhancement dominant along the cross-section of the <span class="hlt">loop</span>, which is independent of time. This feature appears as the <span class="hlt">loop</span> appear and disappear as the <span class="hlt">loop</span> un-visible. This is probably the signature of helical flow along the <span class="hlt">loop</span>. The result suggests that the brightening of this kind of <span class="hlt">loop</span> is probably due to the current dissipation heating in the twisted magnetic field flux tube.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27021591','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27021591"><span><span class="hlt">Driving</span> Task: How Older Drivers' On-Road <span class="hlt">Driving</span> Performance Relates to Abilities, Perceptions, and Restrictions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koppel, Sjaan; Charlton, Judith L; Langford, Jim; Di Stefano, Marilyn; MacDonald, Wendy; Vlahodimitrakou, Zafiroula; Mazer, Barbara L; Gelinas, Isabelle; Vrkljan, Brenda; Eliasz, Kinga; Myers, Anita; Tuokko, Holly A; Marshall, Shawn C</p> <p>2016-06-01</p> <p>This study examined a cohort of 227 older drivers and investigated the relationship between performance on the electronic Driver Observation Schedule (eDOS) <span class="hlt">driving</span> task and: (1) driver characteristics; (2) functional abilities; (3) perceptions of <span class="hlt">driving</span> comfort and abilities; and (4) self-reported <span class="hlt">driving</span> restrictions. Participants (male: 70%; age: M = 81.53 years, SD = 3.37 years) completed a series of functional ability measures and scales on perceived <span class="hlt">driving</span> comfort, abilities, and <span class="hlt">driving</span> restrictions from the Year 2 Candrive/Ozcandrive assessment protocol, along with an eDOS <span class="hlt">driving</span> task. Observations of participants' <span class="hlt">driving</span> behaviours during the <span class="hlt">driving</span> task were recorded for intersection negotiation, lane-changing, merging, low-speed maneuvers, and maneuver-free <span class="hlt">driving</span>. eDOS <span class="hlt">driving</span> task scores were high (M = 94.74; SD = 5.70) and significantly related to participants' perceived <span class="hlt">driving</span> abilities, reported frequency of <span class="hlt">driving</span> in challenging situations, and number of <span class="hlt">driving</span> restrictions. Future analyses will explore potential changes in <span class="hlt">driving</span> task scores over time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994IJSSC..29...67E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994IJSSC..29...67E"><span>Multifrequency zero-jitter delay-locked <span class="hlt">loop</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Efendovich, Avner; Afek, Yachin; Sella, Coby; Bikowsky, Zeev</p> <p>1994-01-01</p> <p>The approach of an all-digital phase locked <span class="hlt">loop</span> is used in this delay-locked <span class="hlt">loop</span> circuit. This design is designated to a system with two processing units, a master CPU and a slave system chip, that share the same bus. It allows maximum utilization of the bus, as the minimal skew between the clocks of the two components significantly reduces idle periods, and also set-up and hold times. Changes in the operating frequency are possible, without falling out of synchronization. Due to the special lead-lag phase detector, the jitter of the clock is zero, when the <span class="hlt">loop</span> is locked, under any working conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1413920-polyakov-loop-correlator-perturbation-theory','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1413920-polyakov-loop-correlator-perturbation-theory"><span>Polyakov <span class="hlt">loop</span> correlator in perturbation theory</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Berwein, Matthias; Brambilla, Nora; Petreczky, Péter; ...</p> <p>2017-07-25</p> <p>We study the Polyakov <span class="hlt">loop</span> correlator in the weak coupling expansion and show how the perturbative series re-exponentiates into singlet and adjoint contributions. We calculate the order g 7 correction to the Polyakov <span class="hlt">loop</span> correlator in the short distance limit. We show how the singlet and adjoint free energies arising from the re-exponentiation formula of the Polyakov <span class="hlt">loop</span> correlator are related to the gauge invariant singlet and octet free energies that can be defined in pNRQCD, namely we find that the two definitions agree at leading order in the multipole expansion, but differ at first order in the quark-antiquark distance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1413920-polyakov-loop-correlator-perturbation-theory','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1413920-polyakov-loop-correlator-perturbation-theory"><span>Polyakov <span class="hlt">loop</span> correlator in perturbation theory</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Berwein, Matthias; Brambilla, Nora; Petreczky, Péter</p> <p></p> <p>We study the Polyakov <span class="hlt">loop</span> correlator in the weak coupling expansion and show how the perturbative series re-exponentiates into singlet and adjoint contributions. We calculate the order g 7 correction to the Polyakov <span class="hlt">loop</span> correlator in the short distance limit. We show how the singlet and adjoint free energies arising from the re-exponentiation formula of the Polyakov <span class="hlt">loop</span> correlator are related to the gauge invariant singlet and octet free energies that can be defined in pNRQCD, namely we find that the two definitions agree at leading order in the multipole expansion, but differ at first order in the quark-antiquark distance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29327083','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29327083"><span>R-<span class="hlt">loops</span>: targets for nuclease cleavage and repeat instability.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Freudenreich, Catherine H</p> <p>2018-01-11</p> <p>R-<span class="hlt">loops</span> form when transcribed RNA remains bound to its DNA template to form a stable RNA:DNA hybrid. Stable R-<span class="hlt">loops</span> form when the RNA is purine-rich, and are further stabilized by DNA secondary structures on the non-template strand. Interestingly, many expandable and disease-causing repeat sequences form stable R-<span class="hlt">loops</span>, and R-<span class="hlt">loops</span> can contribute to repeat instability. Repeat expansions are responsible for multiple neurodegenerative diseases, including Huntington's disease, myotonic dystrophy, and several types of ataxias. Recently, it was found that R-<span class="hlt">loops</span> at an expanded CAG/CTG repeat tract cause DNA breaks as well as repeat instability (Su and Freudenreich, Proc Natl Acad Sci USA 114, E8392-E8401, 2017). Two factors were identified as causing R-<span class="hlt">loop</span>-dependent breaks at CAG/CTG tracts: deamination of cytosines and the MutLγ (Mlh1-Mlh3) endonuclease, defining two new mechanisms for how R-<span class="hlt">loops</span> can generate DNA breaks (Su and Freudenreich, Proc Natl Acad Sci USA 114, E8392-E8401, 2017). Following R-<span class="hlt">loop</span>-dependent nicking, base excision repair resulted in repeat instability. These results have implications for human repeat expansion diseases and provide a paradigm for how RNA:DNA hybrids can cause genome instability at structure-forming DNA sequences. This perspective summarizes mechanisms of R-<span class="hlt">loop</span>-induced fragility at G-rich repeats and new links between DNA breaks and repeat instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21316295-wilson-loops-qcd-string-scattering-amplitudes','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21316295-wilson-loops-qcd-string-scattering-amplitudes"><span>Wilson <span class="hlt">loops</span> and QCD/string scattering amplitudes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Makeenko, Yuri; Olesen, Poul; Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen O</p> <p>2009-07-15</p> <p>We generalize modern ideas about the duality between Wilson <span class="hlt">loops</span> and scattering amplitudes in N=4 super Yang-Mills theory to large N QCD by deriving a general relation between QCD meson scattering amplitudes and Wilson <span class="hlt">loops</span>. We then investigate properties of the open-string disk amplitude integrated over reparametrizations. When the Wilson-<span class="hlt">loop</span> is approximated by the area behavior, we find that the QCD scattering amplitude is a convolution of the standard Koba-Nielsen integrand and a kernel. As usual poles originate from the first factor, whereas no (momentum-dependent) poles can arise from the kernel. We show that the kernel becomes a constant whenmore » the number of external particles becomes large. The usual Veneziano amplitude then emerges in the kinematical regime, where the Wilson <span class="hlt">loop</span> can be reliably approximated by the area behavior. In this case, we obtain a direct duality between Wilson <span class="hlt">loops</span> and scattering amplitudes when spatial variables and momenta are interchanged, in analogy with the N=4 super Yang-Mills theory case.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20377660','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20377660"><span>Closing the <span class="hlt">loop</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dassau, E; Atlas, E; Phillip, M</p> <p>2010-02-01</p> <p>The dream of closing the <span class="hlt">loop</span> is actually the dream of creating an artificial pancreas and freeing the patients from being involved with the care of their own diabetes. Insulin-dependent diabetes (type 1) is a chronic incurable disease which requires constant therapy without the possibility of any 'holidays' or insulin-free days. It means that patients have to inject insulin every day of their life, several times per day, and in order to do it safely they also have to measure their blood glucose levels several times per day. Patients need to plan their meals, their physical activities and their insulin regime - there is only very small room for spontaneous activities. This is why the desire for an artificial pancreas is so strong despite the fact that it will not cure the diabetic patients. Attempts to develop a closed-<span class="hlt">loop</span> system started in the 1960s but never got to a clinical practical stage of development. In recent years the availability of continuous glucose sensors revived those efforts and stimulated the clinician and researchers to believe that closing the <span class="hlt">loop</span> might be possible nowadays. Many papers have been published over the years describing several different ideas on how to close the <span class="hlt">loop</span>. Most of the suggested systems have a sensing arm that measures the blood glucose repeatedly or continuously, an insulin delivery arm that injects insulin upon command and a computer that makes the decisions of when and how much insulin to deliver. The differences between the various published systems in the literature are mainly in their control algorithms. However, there are also differences related to the method and site of glucose measurement and insulin delivery. SC glucose measurements and insulin delivery are the most studied option but other combinations of insulin measurements and glucose delivery including intravascular and intraperitoneal (IP) are explored. We tried to select recent publications that we believe had influenced and inspired people interested</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910035220&hterms=digital+phase+locked+loop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddigital%2Bphase%2Blocked%2Bloop','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910035220&hterms=digital+phase+locked+loop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddigital%2Bphase%2Blocked%2Bloop"><span>An estimator-predictor approach to PLL <span class="hlt">loop</span> filter design</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Statman, Joseph I.; Hurd, William J.</p> <p>1990-01-01</p> <p>The design of digital phase locked <span class="hlt">loops</span> (DPLL) using estimation theory concepts in the selection of a <span class="hlt">loop</span> filter is presented. The key concept, that the DPLL closed-<span class="hlt">loop</span> transfer function is decomposed into an estimator and a predictor, is discussed. The estimator provides recursive estimates of phase, frequency, and higher-order derivatives, and the predictor compensates for the transport lag inherent in the <span class="hlt">loop</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24073774','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24073774"><span>Chinese carless young drivers' self-reported <span class="hlt">driving</span> behavior and simulated <span class="hlt">driving</span> performance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Qian; Jiang, Zuhua; Zheng, Dongpeng; Man, Dong; Xu, Xunnan</p> <p>2013-01-01</p> <p>Carless young drivers refers to those drivers aged between 18 and 25 years who have a driver's license but seldom have opportunities to practice their <span class="hlt">driving</span> skills because they do not have their own cars. Due to China's lower private car ownership, many young drivers become carless young drivers after licensure, and the safety issue associated with them has raised great concern in China. This study aims to provide initial insight into the self-reported <span class="hlt">driving</span> behaviors and simulated <span class="hlt">driving</span> performance of Chinese carless young drivers. Thirty-three carless young drivers and 32 young drivers with their own cars (as a comparison group) participated in this study. A modified Driver Behavior Questionnaire (DBQ) with a 4-factor structure (errors, violations, attention lapses, and memory lapses) was used to study carless young drivers' self-reported <span class="hlt">driving</span> behaviors. A simulated <span class="hlt">driving</span> experiment using a low-cost, fixed-base <span class="hlt">driving</span> simulator was conducted to measure their simulated <span class="hlt">driving</span> performance (errors, violations, attention lapses, <span class="hlt">driving</span> maintenance, reaction time, and accidents). Self-reported DBQ outcomes showed that carless young drivers reported similar errors, more attention lapses, fewer memory lapses, and significantly fewer violation behaviors relative to young drivers with their own cars, whereas simulated <span class="hlt">driving</span> results revealed that they committed significantly more errors, attention lapses, and violation behaviors than the comparison group. Carless young drivers had a lower ability to maintain the stability of speed and lane position, drove more cautiously approaching and passing through red traffic lights, and committed more accidents during simulated <span class="hlt">driving</span>. A tendency to speed was not found among carless young drivers; their average speed and speeding frequency were all much lower than that of the comparison group. Lifetime mileage was the only significant predictor of carless young drivers' self-reported violations, simulated violations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Cross+AND+fit&pg=6&id=EJ1151916','ERIC'); return false;" href="https://eric.ed.gov/?q=Cross+AND+fit&pg=6&id=EJ1151916"><span>N-<span class="hlt">Loop</span> Learning: Part II--An Empirical Investigation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Simonin, Bernard L.</p> <p>2017-01-01</p> <p>Purpose: Through a survey of firm's experiences with strategic alliances and a structural equation modeling approach, the aim of this study is to stimulate further interest in modeling and empirical research in the area of N-<span class="hlt">loop</span> learning. Although the concepts of single-<span class="hlt">loop</span> and double-<span class="hlt">loop</span> learning, in particular, are well established in the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170004338','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170004338"><span>Reconfigurable <span class="hlt">Drive</span> Current System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alhorn, Dean C. (Inventor); Dutton, Kenneth R. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)</p> <p>2017-01-01</p> <p>A reconfigurable <span class="hlt">drive</span> current system includes <span class="hlt">drive</span> stages, each of which includes a high-side transistor and a low-side transistor in a totem pole configuration. A current monitor is coupled to an output of each <span class="hlt">drive</span> stage. Input channels are provided to receive input signals. A processor is coupled to the input channels and to each current monitor for generating at least one <span class="hlt">drive</span> signal using at least one of the input signals and current measured by at least one of the current monitors. A pulse width modulation generator is coupled to the processor and each <span class="hlt">drive</span> stage for varying the <span class="hlt">drive</span> signals as a function of time prior to being supplied to at least one of the <span class="hlt">drive</span> stages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130003201','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130003201"><span>Coronal <span class="hlt">Loop</span> Evolution Observed with AIA and Hi-C</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mulu-Moore, Fana; Winebarger, A.; Cirtain, J.; Kobayashi, K.; Korreck, K.; Golub, L.; Kuzin. S.; Walsh, R.; DeForest, C.; DePontieu, B.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20130003201'); toggleEditAbsImage('author_20130003201_show'); toggleEditAbsImage('author_20130003201_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20130003201_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20130003201_hide"></p> <p>2012-01-01</p> <p>Despite much progress toward understanding the dynamics of the solar corona, the physical properties of coronal <span class="hlt">loops</span> are not yet fully understood. Recent investigations and observations from different instruments have yielded contradictory results about the true physical properties of coronal <span class="hlt">loops</span>. In the past, the evolution of <span class="hlt">loops</span> has been used to infer the <span class="hlt">loop</span> substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this poster we discuss the first results of <span class="hlt">loop</span> analysis comparing AIA and Hi-C data. We find signatures of cooling in a pixel selected along a <span class="hlt">loop</span> structure in the AIA multi-filter observations. However, unlike previous studies, we find that the cooling time is much longer than the draining time. This is inconsistent with previous cooling models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=illegal+AND+legal+AND+drugs&pg=5&id=EJ480716','ERIC'); return false;" href="https://eric.ed.gov/?q=illegal+AND+legal+AND+drugs&pg=5&id=EJ480716"><span>Young, Drunk, Dangerous and <span class="hlt">Driving</span>: Underage Drinking and <span class="hlt">Driving</span> Research Findings.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Little, Robert; Clontz, Kenneth</p> <p>1994-01-01</p> <p>Summarizes major, recent research findings concerning illegal alcohol use and intoxicated <span class="hlt">driving</span> among American youth. Examines what research revealed about the nature of underage drinking and <span class="hlt">driving</span>; what health, social, and legal ramifications are associated with drinking and <span class="hlt">driving</span>; and what characteristics and behavioral patterns are found…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740000274','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740000274"><span>Digital second-order phase-locked <span class="hlt">loop</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Holmes, J. K.; Carl, C. C.; Tagnelia, C. R.</p> <p>1975-01-01</p> <p>Actual tests with second-order digital phase-locked <span class="hlt">loop</span> at simulated relative Doppler shift of 1x0.0001 produced phase lock with timing error of 6.5 deg and no appreciable Doppler bias. <span class="hlt">Loop</span> thus appears to achieve subcarrier synchronization and to remove bias due to Doppler shift in range of interest.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21965362','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21965362"><span>Review article: closed-<span class="hlt">loop</span> systems in anesthesia: is there a potential for closed-<span class="hlt">loop</span> fluid management and hemodynamic optimization?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rinehart, Joseph; Liu, Ngai; Alexander, Brenton; Cannesson, Maxime</p> <p>2012-01-01</p> <p>Closed-<span class="hlt">loop</span> (automated) controllers are encountered in all aspects of modern life in applications ranging from air-conditioning to spaceflight. Although these systems are virtually ubiquitous, they are infrequently used in anesthesiology because of the complexity of physiologic systems and the difficulty in obtaining reliable and valid feedback data from the patient. Despite these challenges, closed-<span class="hlt">loop</span> systems are being increasingly studied and improved for medical use. Two recent developments have made fluid administration a candidate for closed-<span class="hlt">loop</span> control. First, the further description and development of dynamic predictors of fluid responsiveness provides a strong parameter for use as a control variable to guide fluid administration. Second, rapid advances in noninvasive monitoring of cardiac output and other hemodynamic variables make goal-directed therapy applicable for a wide range of patients in a variety of clinical care settings. In this article, we review the history of closed-<span class="hlt">loop</span> controllers in clinical care, discuss the current understanding and limitations of the dynamic predictors of fluid responsiveness, and examine how these variables might be incorporated into a closed-<span class="hlt">loop</span> fluid administration system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27156178','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27156178"><span>Ocular disease and <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wood, Joanne M; Black, Alex A</p> <p>2016-09-01</p> <p>As the <span class="hlt">driving</span> population ages, the number of drivers with visual impairment resulting from ocular disease will increase given the age-related prevalence of ocular disease. The increase in visual impairment in the <span class="hlt">driving</span> population has a number of implications for <span class="hlt">driving</span> outcomes. This review summarises current research regarding the impact of common ocular diseases on <span class="hlt">driving</span> ability and safety, with particular focus on cataract, glaucoma, age-related macular degeneration, hemianopia and diabetic retinopathy. The evidence considered includes self-reported <span class="hlt">driving</span> outcomes, <span class="hlt">driving</span> performance (on-road and simulator-based) and various motor vehicle crash indices. Collectively, this review demonstrates that <span class="hlt">driving</span> ability and safety are negatively affected by ocular disease; however, further research is needed in this area. Older drivers with ocular disease need to be aware of the negative consequences of their ocular condition and in the case where treatment options are available, encouraged to seek these earlier for optimum <span class="hlt">driving</span> safety and quality of life benefits. © 2016 Optometry Australia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3097428','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3097428"><span><span class="hlt">Driving</span> and Neurodegenerative Diseases</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Uc, Ergun Y.; Rizzo, Matthew</p> <p>2011-01-01</p> <p>The proportion of elderly in the general population is rising, resulting in greater numbers of drivers with neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). These neurodegenerative disorders impair cognition, visual perception, and motor function, leading to reduced driver fitness and greater crash risk. Yet medical diagnosis or age alone is not reliable enough to predict driver safety or crashes, or revoke the <span class="hlt">driving</span> privileges of these drivers. <span class="hlt">Driving</span> research utilizes tools such as questionnaires about <span class="hlt">driving</span> habits and history, <span class="hlt">driving</span> simulators, standardized road tests utilizing instrumented vehicles, and state <span class="hlt">driving</span> records. Research challenges include outlining the evolution of <span class="hlt">driving</span> safety, understanding the mechanisms of <span class="hlt">driving</span> impairment, and developing a reliable and efficient standardized test battery for prediction of driver safety in neurodegenerative disorders. This information will enable healthcare providers to advise their patients with neurodegenerative disorders with more certainty, affect policy, and help to develop rehabilitative measures for <span class="hlt">driving</span>. PMID:18713573</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720045438&hterms=digital+phase+locked+loop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Ddigital%2Bphase%2Blocked%2Bloop','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720045438&hterms=digital+phase+locked+loop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Ddigital%2Bphase%2Blocked%2Bloop"><span>Digital simulation of hybrid <span class="hlt">loop</span> operation in RFI backgrounds.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ziemer, R. E.; Nelson, D. R.</p> <p>1972-01-01</p> <p>A digital computer model for Monte-Carlo simulation of an imperfect second-order hybrid phase-locked <span class="hlt">loop</span> (PLL) operating in radio-frequency interference (RFI) and Gaussian noise backgrounds has been developed. Characterization of hybrid <span class="hlt">loop</span> performance in terms of cycle slipping statistics and phase error variance, through computer simulation, indicates that the hybrid <span class="hlt">loop</span> has desirable performance characteristics in RFI backgrounds over the conventional PLL or the costas <span class="hlt">loop</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvL.119m8101B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvL.119m8101B"><span>Nonequilibrium Chromosome <span class="hlt">Looping</span> via Molecular Slip Links</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brackley, C. A.; Johnson, J.; Michieletto, D.; Morozov, A. N.; Nicodemi, M.; Cook, P. R.; Marenduzzo, D.</p> <p>2017-09-01</p> <p>We propose a model for the formation of chromatin <span class="hlt">loops</span> based on the diffusive sliding of molecular slip links. These mimic the behavior of molecules like cohesin, which, along with the CTCF protein, stabilize <span class="hlt">loops</span> which contribute to organizing the genome. By combining 3D Brownian dynamics simulations and 1D exactly solvable nonequilibrium models, we show that diffusive sliding is sufficient to account for the strong bias in favor of convergent CTCF-mediated chromosome <span class="hlt">loops</span> observed experimentally. We also find that the diffusive motion of multiple slip links along chromatin is rectified by an intriguing ratchet effect that arises if slip links bind to the chromatin at a preferred "loading site." This emergent collective behavior favors the extrusion of <span class="hlt">loops</span> which are much larger than the ones formed by single slip links.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12850081','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12850081"><span>Assessing the <span class="hlt">driving</span> performance of older adult drivers: on-road versus simulated <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Hoe C; Cameron, Don; Lee, Andy H</p> <p>2003-09-01</p> <p>To validate a laboratory-based <span class="hlt">driving</span> simulator in measuring on-road <span class="hlt">driving</span> performance, 129 older adult drivers were assessed with both the simulator and an on-road test. The <span class="hlt">driving</span> performance of the participants was gauged by appropriate and reliable age-specific assessment criteria, which were found to be negatively correlated with age. Using principal component analysis, two performance indices were developed from the criteria to represent the overall performance in simulated <span class="hlt">driving</span> and the on-road assessment. There was significant positive association between the two indices, with the simulated <span class="hlt">driving</span> performance index explaining over two-thirds of the variability of the on-road <span class="hlt">driving</span> performance index, after adjustment for age and gender of the drivers. The results supported the validity of the <span class="hlt">driving</span> simulator and it is a safer and more economical method than the on-road testing to assess the <span class="hlt">driving</span> performance of older adult drivers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5774811','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5774811"><span>Proactive vs. reactive car <span class="hlt">driving</span>: EEG evidence for different <span class="hlt">driving</span> strategies of older drivers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wascher, Edmund; Getzmann, Stephan</p> <p>2018-01-01</p> <p>Aging is associated with a large heterogeneity in the extent of age-related changes in sensory, motor, and cognitive functions. All these functions can influence the performance in complex tasks like car <span class="hlt">driving</span>. The present study aims to identify potential differences in underlying cognitive processes that may explain inter-individual variability in <span class="hlt">driving</span> performance. Younger and older participants performed a one-hour monotonous <span class="hlt">driving</span> task in a <span class="hlt">driving</span> simulator under varying crosswind conditions, while behavioral and electrophysiological data were recorded. Overall, younger and older drivers showed comparable <span class="hlt">driving</span> performance (lane keeping). However, there was a large difference in <span class="hlt">driving</span> lane variability within the older group. Dividing the older group in two subgroups with low vs. high <span class="hlt">driving</span> lane variability revealed differences between the two groups in electrophysiological correlates of mental workload, consumption of mental resources, and activation and sustaining of attention: Older drivers with high <span class="hlt">driving</span> lane variability showed higher frontal Alpha and Theta activity than older drivers with low <span class="hlt">driving</span> lane variability and—with increasing crosswind—a more pronounced decrease in Beta activity. These results suggest differences in <span class="hlt">driving</span> strategies of older and younger drivers, with the older drivers using either a rather proactive and alert <span class="hlt">driving</span> strategy (indicated by low <span class="hlt">driving</span> lane variability and lower Alpha and Beta activity), or a rather reactive strategy (indicated by high <span class="hlt">driving</span> lane variability and higher Alpha activity). PMID:29352314</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950007647','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950007647"><span>VERDEX: A virtual environment demonstrator for remote <span class="hlt">driving</span> applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stone, Robert J.</p> <p>1991-01-01</p> <p>One of the key areas of the National Advanced Robotics Centre's enabling technologies research program is that of the human system interface, phase 1 of which started in July 1989 and is currently addressing the potential of virtual environments to permit intuitive and natural interactions between a human operator and a remote robotic vehicle. The aim of the first 12 months of this program (to September, 1990) is to develop a virtual human-interface demonstrator for use later as a test bed for human factors experimentation. This presentation will describe the current state of development of the test bed, and will outline some human factors issues and problems for more general discussion. In brief, the virtual telepresence system for remote <span class="hlt">driving</span> has been designed to take the following form. The human operator will be provided with a helmet-mounted stereo display assembly, facilities for speech recognition and synthesis (using the Marconi Macrospeak system), and a VPL DataGlove Model 2 unit. The vehicle to be used for the purposes of remote <span class="hlt">driving</span> is a Cybermotion Navmaster K2A system, which will be equipped with a stereo camera and microphone pair, mounted on a motorized high-speed pan-and-tilt head incorporating a closed-<span class="hlt">loop</span> laser ranging sensor for camera convergence control (currently under contractual development). It will be possible to relay information to and from the vehicle and sensory system via an umbilical or RF link. The aim is to develop an interactive audio-visual display system capable of presenting combined stereo TV pictures and virtual graphics windows, the latter featuring control representations appropriate for vehicle <span class="hlt">driving</span> and interaction using a graphical 'hand,' slaved to the flex and tracking sensors of the DataGlove and an additional helmet-mounted Polhemus IsoTrack sensor. Developments planned for the virtual environment test bed include transfer of operator control between remote <span class="hlt">driving</span> and remote manipulation, dexterous end</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22370040-unresolved-fine-scale-structure-solar-coronal-loop-tops','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22370040-unresolved-fine-scale-structure-solar-coronal-loop-tops"><span>Unresolved fine-scale structure in solar coronal <span class="hlt">loop</span>-tops</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Scullion, E.; Van der Voort, L. Rouppe; Wedemeyer, S.</p> <p>2014-12-10</p> <p>New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal <span class="hlt">loops</span> in greater detail. We continue to discover even finer substructures within coronal <span class="hlt">loop</span> cross-sections, in order to understand the nature of the solar corona. Here, we push this lower limit further to search for the finest coronal <span class="hlt">loop</span> substructures, through taking advantage of the resolving power of the Swedish 1 m Solar Telescope/CRisp Imaging Spectro-Polarimeter (CRISP), together with co-observations from the Solar Dynamics Observatory/Atmospheric Image Assembly (AIA). High-resolution imaging of the chromospheric Hα 656.28 nm spectral line core and wings can, under certainmore » circumstances, allow one to deduce the topology of the local magnetic environment of the solar atmosphere where its observed. Here, we study post-flare coronal <span class="hlt">loops</span>, which become filled with evaporated chromosphere that rapidly condenses into chromospheric clumps of plasma (detectable in Hα) known as a coronal rain, to investigate their fine-scale structure. We identify, through analysis of three data sets, large-scale catastrophic cooling in coronal <span class="hlt">loop</span>-tops and the existence of multi-thermal, multi-stranded substructures. Many cool strands even extend fully intact from <span class="hlt">loop</span>-top to footpoint. We discover that coronal <span class="hlt">loop</span> fine-scale strands can appear bunched with as many as eight parallel strands within an AIA coronal <span class="hlt">loop</span> cross-section. The strand number density versus cross-sectional width distribution, as detected by CRISP within AIA-defined coronal <span class="hlt">loops</span>, most likely peaks at well below 100 km, and currently, 69% of the substructure strands are statistically unresolved in AIA coronal <span class="hlt">loops</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21063868','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21063868"><span>Positive effects of Red Bull® Energy Drink on <span class="hlt">driving</span> performance during prolonged <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mets, Monique A J; Ketzer, Sander; Blom, Camilla; van Gerven, Maartje H; van Willigenburg, Gitta M; Olivier, Berend; Verster, Joris C</p> <p>2011-04-01</p> <p>The purpose of this study was to examine if Red Bull® Energy Drink can counteract sleepiness and <span class="hlt">driving</span> impairment during prolonged <span class="hlt">driving</span>. Twenty-four healthy volunteers participated in this double-blind placebo-controlled crossover study. After 2 h of highway <span class="hlt">driving</span> in the STISIM <span class="hlt">driving</span> simulator, subjects had a 15-min break and consumed Red Bull® Energy Drink (250 ml) or placebo (Red Bull® Energy Drink without the functional ingredients: caffeine, taurine, glucuronolactone, B vitamins (niacin, pantothenic acid, B6, B12), and inositol) before <span class="hlt">driving</span> for two additional hours. A third condition comprised 4 h of uninterrupted <span class="hlt">driving</span>. Primary parameter was the standard deviation of lateral position (SDLP), i.e., the weaving of the car. Secondary parameters included SD speed, subjective <span class="hlt">driving</span> quality, sleepiness, and mental effort to perform the test. No significant differences were observed during the first 2 h of <span class="hlt">driving</span>. Red Bull® Energy Drink significantly improved <span class="hlt">driving</span> relative to placebo: SDLP was significantly reduced during the 3rd (p < 0.046) and 4th hour of <span class="hlt">driving</span> (p < 0.011). Red Bull® Energy Drink significantly reduced the standard deviation of speed (p < 0.004), improved subjective <span class="hlt">driving</span> quality (p < 0.0001), and reduced mental effort to perform the test (p < 0.024) during the 3rd hour of <span class="hlt">driving</span>. Subjective sleepiness was significantly decreased during both the 3rd and 4th hour of <span class="hlt">driving</span> after Red Bull® Energy Drink (p < 0.001 and p < 0.009, respectively). Relative to uninterrupted <span class="hlt">driving</span>, Red Bull® Energy Drink significantly improved each parameter. Red Bull® Energy Drink significantly improves <span class="hlt">driving</span> performance and reduces driver sleepiness during prolonged highway <span class="hlt">driving</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1237305','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1237305"><span>Hardware-in-the-<span class="hlt">Loop</span> Testing of Utility-Scale Wind Turbine Generators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Schkoda, Ryan; Fox, Curtiss; Hadidi, Ramtin</p> <p>2016-01-26</p> <p>Historically, wind turbine prototypes were tested in the field, which was--and continues to be--a slow and expensive process. As a result, wind turbine dynamometer facilities were developed to provide a more cost-effective alternative to field testing. New turbine designs were tested and the design models were validated using dynamometers to <span class="hlt">drive</span> the turbines in a controlled environment. Over the years, both wind turbine dynamometer testing and computer technology have matured and improved, and the two are now being joined to provide hardware-in-the-<span class="hlt">loop</span> (HIL) testing. This type of testing uses a computer to simulate the items that are missing from amore » dynamometer test, such as grid stiffness, voltage, frequency, rotor, and hub. Furthermore, wind input and changing electric grid conditions can now be simulated in real time. This recent advance has greatly increased the utility of dynamometer testing for the development of wind turbine systems.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4329470','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4329470"><span>Mechanosignaling through YAP and TAZ <span class="hlt">drives</span> fibroblast activation and fibrosis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Fei; Lagares, David; Choi, Kyoung Moo; Stopfer, Lauren; Marinković, Aleksandar; Vrbanac, Vladimir; Probst, Clemens K.; Hiemer, Samantha E.; Sisson, Thomas H.; Horowitz, Jeffrey C.; Rosas, Ivan O.; Fredenburgh, Laura E.; Feghali-Bostwick, Carol; Varelas, Xaralabos; Tager, Andrew M.</p> <p>2014-01-01</p> <p>Pathological fibrosis is driven by a feedback <span class="hlt">loop</span> in which the fibrotic extracellular matrix is both a cause and consequence of fibroblast activation. However, the molecular mechanisms underlying this process remain poorly understood. Here we identify yes-associated protein (YAP) (homolog of drosophila Yki) and transcriptional coactivator with PDZ-binding motif (TAZ) (also known as Wwtr1), transcriptional effectors of the Hippo pathway, as key matrix stiffness-regulated coordinators of fibroblast activation and matrix synthesis. YAP and TAZ are prominently expressed in fibrotic but not healthy lung tissue, with particularly pronounced nuclear expression of TAZ in spindle-shaped fibroblastic cells. In culture, both YAP and TAZ accumulate in the nuclei of fibroblasts grown on pathologically stiff matrices but not physiologically compliant matrices. Knockdown of YAP and TAZ together in vitro attenuates key fibroblast functions, including matrix synthesis, contraction, and proliferation, and does so exclusively on pathologically stiff matrices. Profibrotic effects of YAP and TAZ operate, in part, through their transcriptional target plasminogen activator inhibitor-1, which is regulated by matrix stiffness independent of transforming growth factor-β signaling. Immortalized fibroblasts conditionally expressing active YAP or TAZ mutant proteins overcome soft matrix limitations on growth and promote fibrosis when adoptively transferred to the murine lung, demonstrating the ability of fibroblast YAP/TAZ activation to <span class="hlt">drive</span> a profibrotic response in vivo. Together, these results identify YAP and TAZ as mechanoactivated coordinators of the matrix-driven feedback <span class="hlt">loop</span> that amplifies and sustains fibrosis. PMID:25502501</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.115l1603G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.115l1603G"><span><span class="hlt">Loop</span> Integrands for Scattering Amplitudes from the Riemann Sphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geyer, Yvonne; Mason, Lionel; Monteiro, Ricardo; Tourkine, Piotr</p> <p>2015-09-01</p> <p>The scattering equations on the Riemann sphere give rise to remarkable formulas for tree-level gauge theory and gravity amplitudes. Adamo, Casali, and Skinner conjectured a one-<span class="hlt">loop</span> formula for supergravity amplitudes based on scattering equations on a torus. We use a residue theorem to transform this into a formula on the Riemann sphere. What emerges is a framework for <span class="hlt">loop</span> integrands on the Riemann sphere that promises to have a wide application, based on off-shell scattering equations that depend on the <span class="hlt">loop</span> momentum. We present new formulas, checked explicitly at low points, for supergravity and super-Yang-Mills amplitudes and for n -gon integrands at one <span class="hlt">loop</span>. Finally, we show that the off-shell scattering equations naturally extend to arbitrary <span class="hlt">loop</span> order, and we give a proposal for the all-<span class="hlt">loop</span> integrands for supergravity and planar super-Yang-Mills theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/19016','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/19016"><span>Installation report, state demonstration project, <span class="hlt">loop</span> detectors.</span></a></p> <p><a target="_blank" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>1982-01-01</p> <p>The Virginia Department of Highways and Transportation frequently utilizes induction <span class="hlt">loops</span> in its vehicle detector systems. Although not documented, there have been many instances of <span class="hlt">loop</span> failure; therefore, the practices and materials used by the De...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..DPPJP6013N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..DPPJP6013N"><span>Process Model of A Fusion Fuel Recovery System for a Direct <span class="hlt">Drive</span> IFE Power Reactor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Natta, Saswathi; Aristova, Maria; Gentile, Charles</p> <p>2008-11-01</p> <p>A task has been initiated to develop a detailed representative model for the fuel recovery system (FRS) in the prospective direct <span class="hlt">drive</span> inertial fusion energy (IFE) reactor. As part of the conceptual design phase of the project, a chemical process model is developed in order to observe the interaction of system components. This process model is developed using FEMLAB Multiphysics software with the corresponding chemical engineering module (CEM). Initially, the reactants, system structure, and processes are defined using known chemical species of the target chamber exhaust. Each step within the Fuel recovery system is modeled compartmentally and then merged to form the closed <span class="hlt">loop</span> fuel recovery system. The output, which includes physical properties and chemical content of the products, is analyzed after each step of the system to determine the most efficient and productive system parameters. This will serve to attenuate possible bottlenecks in the system. This modeling evaluation is instrumental in optimizing and closing the fusion fuel cycle in a direct <span class="hlt">drive</span> IFE power reactor. The results of the modeling are presented in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22364342','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22364342"><span><span class="hlt">Drive</span> for muscularity and <span class="hlt">drive</span> for thinness: the impact of pro-anorexia websites.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Juarez, Lilia; Soto, Ernesto; Pritchard, Mary E</p> <p>2012-01-01</p> <p>In recent years, websites that stress the message of thinness as the ideal and only choice have surfaced on the internet. The possibility that pro-anorexia websites may reinforce restrictive eating and exercise behaviors is an area of concern. In addition, friends may be influencing one another to view these websites, further contributing to <span class="hlt">drive</span> for thinness in women and <span class="hlt">drive</span> for muscularity in men. Three hundred male and female undergraduate psychology students responded to questionnaires assessing: internalization of pro-anorexia website content, internalization of general media content, influence of friends to view pro-anorexia websites, peer influence, <span class="hlt">drive</span> for muscularity, and <span class="hlt">drive</span> for thinness. Results showed internalization of pro-anorexia website content was positively correlated with <span class="hlt">drive</span> for thinness in women, and negatively correlated with <span class="hlt">drive</span> for muscularity in men. Internalization of pro-anorexia website content was found to be related to both <span class="hlt">drive</span> for thinness in women and <span class="hlt">drive</span> for muscularity in men.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4361471','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4361471"><span>Reading Text While <span class="hlt">Driving</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Horrey, William J.; Hoffman, Joshua D.</p> <p>2015-01-01</p> <p>Objective In this study, we investigated how drivers adapt secondary-task initiation and time-sharing behavior when faced with fluctuating <span class="hlt">driving</span> demands. Background Reading text while <span class="hlt">driving</span> is particularly detrimental; however, in real-world <span class="hlt">driving</span>, drivers actively decide when to perform the task. Method In a test track experiment, participants were free to decide when to read messages while <span class="hlt">driving</span> along a straight road consisting of an area with increased <span class="hlt">driving</span> demands (demand zone) followed by an area with low demands. A message was made available shortly before the vehicle entered the demand zone. We manipulated the type of <span class="hlt">driving</span> demands (baseline, narrow lane, pace clock, combined), message format (no message, paragraph, parsed), and the distance from the demand zone when the message was available (near, far). Results In all conditions, drivers started reading messages (drivers’ first glance to the display) before entering or before leaving the demand zone but tended to wait longer when faced with increased <span class="hlt">driving</span> demands. While reading messages, drivers looked more or less off road, depending on types of <span class="hlt">driving</span> demands. Conclusions For task initiation, drivers avoid transitions from low to high demands; however, they are not discouraged when <span class="hlt">driving</span> demands are already elevated. Drivers adjust time-sharing behavior according to <span class="hlt">driving</span> demands while performing secondary tasks. Nonetheless, such adjustment may be less effective when total demands are high. Application This study helps us to understand a driver’s role as an active controller in the context of distracted <span class="hlt">driving</span> and provides insights for developing distraction interventions. PMID:25850162</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27756701','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27756701"><span>Tonic accommodation predicts closed-<span class="hlt">loop</span> accommodation responses.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Chunming; Drew, Stefanie A; Borsting, Eric; Escobar, Amy; Stark, Lawrence; Chase, Christopher</p> <p>2016-12-01</p> <p>The purpose of this study is to examine the potential relationship between tonic accommodation (TA), near work induced TA-adaptation and the steady state closed-<span class="hlt">loop</span> accommodation response (AR). Forty-two graduate students participated in the study. Various aspects of their accommodation system were objectively measured using an open-field infrared auto-refractor (Grand Seiko WAM-5500). Tonic accommodation was assessed in a completely dark environment. The association between TA and closed-<span class="hlt">loop</span> AR was assessed using linear regression correlations and t-test comparisons. Initial mean baseline TA was 1.84diopter (D) (SD±1.29D) with a wide distribution range (-0.43D to 5.14D). For monocular visual tasks, baseline TA was significantly correlated with the closed-<span class="hlt">loop</span> AR. The slope of the best fit line indicated that closed-<span class="hlt">loop</span> AR varied by approximately 0.3D for every 1D change in TA. This ratio was consistent across a variety of viewing distances and different near work tasks, including both static targets and continuous reading. Binocular reading conditions weakened the correlation between baseline TA and AR, although results remained statistically significant. The 10min near reading task with a 3D demand did not reveal significant near work induced TA-adaptation for either monocular or binocular conditions. Consistently, the TA-adaptation did not show any correlation with AR during reading. This study found a strong association between open-<span class="hlt">loop</span> TA and closed-<span class="hlt">loop</span> AR across a variety of viewing distances and different near work tasks. Difference between the correlations under monocular and binocular reading condition suggests a potential role for vergence compensation during binocular closed-<span class="hlt">loop</span> AR. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JChPh.148d4903Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JChPh.148d4903Z"><span>Phase transitions in single macromolecules: <span class="hlt">Loop</span>-stretch transition versus <span class="hlt">loop</span> adsorption transition in end-grafted polymer chains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Shuangshuang; Qi, Shuanhu; Klushin, Leonid I.; Skvortsov, Alexander M.; Yan, Dadong; Schmid, Friederike</p> <p>2018-01-01</p> <p>We use Brownian dynamics simulations and analytical theory to compare two prominent types of single molecule transitions. One is the adsorption transition of a <span class="hlt">loop</span> (a chain with two ends bound to an attractive substrate) driven by an attraction parameter ɛ and the other is the <span class="hlt">loop</span>-stretch transition in a chain with one end attached to a repulsive substrate, driven by an external end-force F applied to the free end. Specifically, we compare the behavior of the respective order parameters of the transitions, i.e., the mean number of surface contacts in the case of the adsorption transition and the mean position of the chain end in the case of the <span class="hlt">loop</span>-stretch transition. Close to the transition points, both the static behavior and the dynamic behavior of chains with different length N are very well described by a scaling ansatz with the scaling parameters (ɛ - ɛ*)Nϕ (adsorption transition) and (F - F*)Nν (<span class="hlt">loop</span>-stretch transition), respectively, where ϕ is the crossover exponent of the adsorption transition and ν is the Flory exponent. We show that both the <span class="hlt">loop</span>-stretch and the <span class="hlt">loop</span> adsorption transitions provide an exceptional opportunity to construct explicit analytical expressions for the crossover functions which perfectly describe all simulation results on static properties in the finite-size scaling regime. Explicit crossover functions are based on the ansatz for the analytical form of the order parameter distributions at the respective transition points. In contrast to the close similarity in equilibrium static behavior, the dynamic relaxation at the two transitions shows qualitative differences, especially in the strongly ordered regimes. This is attributed to the fact that the surface contact dynamics in a strongly adsorbed chain is governed by local processes, whereas the end height relaxation of a strongly stretched chain involves the full spectrum of Rouse modes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4118681','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4118681"><span>Creating stable stem regions for <span class="hlt">loop</span> elongation in Fcabs — Insights from combining yeast surface display, in silico <span class="hlt">loop</span> reconstruction and molecular dynamics simulations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hasenhindl, Christoph; Lai, Balder; Delgado, Javier; Traxlmayr, Michael W.; Stadlmayr, Gerhard; Rüker, Florian; Serrano, Luis; Oostenbrink, Chris; Obinger, Christian</p> <p>2014-01-01</p> <p>Fcabs (Fc antigen binding) are crystallizable fragments of IgG where the C-terminal structural <span class="hlt">loops</span> of the CH3 domain are engineered for antigen binding. For the design of libraries it is beneficial to know positions that will permit <span class="hlt">loop</span> elongation to increase the potential interaction surface with antigen. However, the insertion of additional <span class="hlt">loop</span> residues might impair the immunoglobulin fold. In the present work we have probed whether stabilizing mutations flanking the randomized and elongated <span class="hlt">loop</span> region improve the quality of Fcab libraries. In detail, 13 libraries were constructed having the C-terminal part of the EF <span class="hlt">loop</span> randomized and carrying additional residues (1, 2, 3, 5 or 10, respectively) in the absence and presence of two flanking mutations. The latter have been demonstrated to increase the thermal stability of the CH3 domain of the respective solubly expressed proteins. Assessment of the stability of the libraries expressed on the surface of yeast cells by flow cytometry demonstrated that <span class="hlt">loop</span> elongation was considerably better tolerated in the stabilized libraries. By using in silico <span class="hlt">loop</span> reconstruction and mimicking randomization together with MD simulations the underlying molecular dynamics were investigated. In the presence of stabilizing stem residues the backbone flexibility of the engineered EF <span class="hlt">loop</span> as well as the fluctuation between its accessible conformations were decreased. In addition the CD <span class="hlt">loop</span> (but not the AB <span class="hlt">loop</span>) and most of the framework regions were rigidified. The obtained data are discussed with respect to the design of Fcabs and available data on the relation between flexibility and affinity of CDR <span class="hlt">loops</span> in Ig-like molecules. PMID:24792385</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPD....4810612D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPD....4810612D"><span>Ponderomotive Acceleration in Coronal <span class="hlt">Loops</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dahlburg, Russell B.; Laming, J. Martin; Taylor, Brian; Obenschain, Keith</p> <p>2017-08-01</p> <p>Ponderomotive acceleration has been asserted to be a cause of the First Ionization Potential (FIP) effect, the by now well known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal <span class="hlt">loops</span>, with the appropriate magnitude and direction, as a ``byproduct'' of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of a coronal <span class="hlt">loops</span> with an axial magnetic field from 0.005 Teslas to 0.02 Teslas and lengths from 25000 km to 75000 km are presented. In the simulations the footpoints of the axial <span class="hlt">loop</span> magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets which act to heat the <span class="hlt">loop</span>. As a consequence of coronal magnetic reconnection, small scale, high speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/20849665-current-drive','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/20849665-current-drive"><span>Current <span class="hlt">Drive</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Faulconer, D.W</p> <p>2004-03-15</p> <p>Certain devices aimed at magnetic confinement of thermonuclear plasma rely on the steady flow of an electric current in the plasma. In view of the dominant place it occupies in both the world magnetic-confinement fusion effort and the author's own activity, the tokamak toroidal configuration is selected as prototype for discussing the question of how such a current can be maintained. Tokamaks require a stationary toroidal plasma current, this being traditionally provided by a pulsed magnetic induction which <span class="hlt">drives</span> the plasma ring as the secondary of a transformer. Since this mechanism is essentially transient, and steady-state fusion reactor operation hasmore » manifold advantages, significant effort is now devoted to developing alternate steady-state means of generating toroidal current. These methods are classed under the global heading of 'noninductive current <span class="hlt">drive</span>' or simply 'current <span class="hlt">drive</span>', generally, though not exclusively, employing the injection of waves and/or toroidally directed particle beams. In what follows we highlight the physical mechanisms underlying surprisingly various approaches to <span class="hlt">driving</span> current in a tokamak, downplaying a number of practical and technical issues. When a significant data base exists for a given method, its experimental current <span class="hlt">drive</span> efficiency and future prospects are detailed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27340971','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27340971"><span>Drinking-and-<span class="hlt">Driving</span>-Related Cognitions Mediate the Relationship Between Alcohol Demand and Alcohol-Impaired <span class="hlt">Driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Amlung, Michael; Morris, David H; Hatz, Laura E; Teeters, Jenni B; Murphy, James G; McCarthy, Denis M</p> <p>2016-07-01</p> <p>Elevated behavioral economic demand for alcohol has been shown to be associated with drinking and <span class="hlt">driving</span> in college students. The present study sought to clarify the underlying mechanisms of this relationship by examining whether drinking-and-<span class="hlt">driving</span>-related cognitions (e.g., attitudes, perceptions, and normative beliefs) mediate the association between alcohol demand and drinking and <span class="hlt">driving</span>. A total of 134 young adult social drinkers completed an alcohol purchase task and measures of perceived dangerousness of drinking and <span class="hlt">driving</span>, normative beliefs about drinking and <span class="hlt">driving</span>, and perceived <span class="hlt">driving</span> limit (i.e., perceived number of drinks one could consume and still <span class="hlt">drive</span> safely). The frequency of drinking and <span class="hlt">driving</span> in the past year was assessed via self-report. Individuals who reported drinking and <span class="hlt">driving</span> exhibited greater alcohol demand (intensity, Omax, and elasticity) compared with those who did not engage in drinking and <span class="hlt">driving</span>. Increased demand was also correlated with more favorable drinking-and-<span class="hlt">driving</span> cognitions. Indirect effects tests revealed that perceived <span class="hlt">driving</span> limit partially mediated the relationship between alcohol demand and drinking-and-<span class="hlt">driving</span> behavior, even after accounting for drinking level, sex, and delay discounting. These findings provide further support for the utility of behavioral economic theory in understanding drinking-and-<span class="hlt">driving</span> behavior. In particular, they provide evidence for one mechanism-drinking-and-<span class="hlt">driving</span>-related cognitions-by which alcohol demand influences drinking and <span class="hlt">driving</span>. Additional research using longitudinal and experimental designs is required to confirm this model and to identify other potential mediators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26951244','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26951244"><span><span class="hlt">Loop</span> Diuretics in the Treatment of Hypertension.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Malha, Line; Mann, Samuel J</p> <p>2016-04-01</p> <p><span class="hlt">Loop</span> diuretics are not recommended in current hypertension guidelines largely due to the lack of outcome data. Nevertheless, they have been shown to lower blood pressure and to offer potential advantages over thiazide-type diuretics. Torsemide offers advantages of longer duration of action and once daily dosing (vs. furosemide and bumetanide) and more reliable bioavailability (vs. furosemide). Studies show that the previously employed high doses of thiazide-type diuretics lower BP more than furosemide. <span class="hlt">Loop</span> diuretics appear to have a preferable side effect profile (less hyponatremia, hypokalemia, and possibly less glucose intolerance). Studies comparing efficacy and side effect profiles of <span class="hlt">loop</span> diuretics with the lower, currently widely prescribed, thiazide doses are needed. Research is needed to fill gaps in knowledge and common misconceptions about <span class="hlt">loop</span> diuretic use in hypertension and to determine their rightful place in the antihypertensive arsenal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820054023&hterms=corkscrew&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcorkscrew','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820054023&hterms=corkscrew&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcorkscrew"><span>A magnetohydrodynamic theory of coronal <span class="hlt">loop</span> transients</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yeh, T.</p> <p>1982-01-01</p> <p>The physical and geometrical characteristics of solar coronal <span class="hlt">loop</span> transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a <span class="hlt">loop</span> is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the <span class="hlt">loop</span> off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the <span class="hlt">loop</span> to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26171288','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26171288"><span>Closed-<span class="hlt">loop</span> conductance scanning tunneling spectroscopy: demonstrating the equivalence to the open-<span class="hlt">loop</span> alternative.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hellenthal, Chris; Sotthewes, Kai; Siekman, Martin H; Kooij, E Stefan; Zandvliet, Harold J W</p> <p>2015-01-01</p> <p>We demonstrate the validity of using closed-<span class="hlt">loop</span> z(V) conductance scanning tunneling spectroscopy (STS) measurements for the determination of the effective tunneling barrier by comparing them to more conventional open-<span class="hlt">loop</span> I(z) measurements. Through the development of a numerical model, the individual contributions to the effective tunneling barrier present in these experiments, such as the work function and the presence of an image charge, are determined quantitatively. This opens up the possibility of determining tunneling barriers of both vacuum and molecular systems in an alternative and more detailed manner.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023585','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023585"><span>Linear Back-<span class="hlt">Drive</span> Differentials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Waydo, Peter</p> <p>2003-01-01</p> <p>Linear back-<span class="hlt">drive</span> differentials have been proposed as alternatives to conventional gear differentials for applications in which there is only limited rotational motion (e.g., oscillation). The finite nature of the rotation makes it possible to optimize a linear back-<span class="hlt">drive</span> differential in ways that would not be possible for gear differentials or other differentials that are required to be capable of unlimited rotation. As a result, relative to gear differentials, linear back-<span class="hlt">drive</span> differentials could be more compact and less massive, could contain fewer complex parts, and could be less sensitive to variations in the viscosities of lubricants. Linear back-<span class="hlt">drive</span> differentials would operate according to established principles of power ball screws and linear-motion <span class="hlt">drives</span>, but would utilize these principles in an innovative way. One major characteristic of such mechanisms that would be exploited in linear back-<span class="hlt">drive</span> differentials is the possibility of designing them to <span class="hlt">drive</span> or back-<span class="hlt">drive</span> with similar efficiency and energy input: in other words, such a mechanism can be designed so that a rotating screw can <span class="hlt">drive</span> a nut linearly or the linear motion of the nut can cause the screw to rotate. A linear back-<span class="hlt">drive</span> differential (see figure) would include two collinear shafts connected to two parts that are intended to engage in limited opposing rotations. The linear back-<span class="hlt">drive</span> differential would also include a nut that would be free to translate along its axis but not to rotate. The inner surface of the nut would be right-hand threaded at one end and left-hand threaded at the opposite end to engage corresponding right- and left-handed threads on the shafts. A rotation and torque introduced into the system via one shaft would <span class="hlt">drive</span> the nut in linear motion. The nut, in turn, would back-<span class="hlt">drive</span> the other shaft, creating a reaction torque. Balls would reduce friction, making it possible for the shaft/nut coupling on each side to operate with 90 percent efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CQGra..29x9001D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CQGra..29x9001D"><span>BOOK REVIEW: A First Course in <span class="hlt">Loop</span> Quantum Gravity A First Course in <span class="hlt">Loop</span> Quantum Gravity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dittrich, Bianca</p> <p>2012-12-01</p> <p>Students who are interested in quantum gravity usually face the difficulty of working through a large amount of prerequisite material before being able to deal with actual quantum gravity. A First Course in <span class="hlt">Loop</span> Quantum Gravity by Rodolfo Gambini and Jorge Pullin, aimed at undergraduate students, marvellously succeeds in starting from the basics of special relativity and covering basic topics in Hamiltonian dynamics, Yang Mills theory, general relativity and quantum field theory, ending with a tour on current (<span class="hlt">loop</span>) quantum gravity research. This is all done in a short 173 pages! As such the authors cannot cover any of the subjects in depth and indeed this book should be seen more as a motivation and orientation guide so that students can go on to follow the hints for further reading. Also, as there are many subjects to cover beforehand, slightly more than half of the book is concerned with more general subjects (special and general relativity, Hamiltonian dynamics, constrained systems, quantization) before the starting point for <span class="hlt">loop</span> quantum gravity, the Ashtekar variables, are introduced. The approach taken by the authors is heuristic and uses simplifying examples in many places. However they take care in motivating all the main steps and succeed in presenting the material pedagogically. Problem sets are provided throughout and references for further reading are given. Despite the shortness of space, alternative viewpoints are mentioned and the reader is also referred to experimental results and bounds. In the second half of the book the reader gets a ride through <span class="hlt">loop</span> quantum gravity; the material covers geometric operators and their spectra, the Hamiltonian constraints, <span class="hlt">loop</span> quantum cosmology and, more broadly, black hole thermodynamics. A glimpse of recent developments and open problems is given, for instance a discussion on experimental predictions, where the authors carefully point out the very preliminary nature of the results. The authors close with an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25490807','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25490807"><span>Carryover effects of highly automated convoy <span class="hlt">driving</span> on subsequent manual <span class="hlt">driving</span> performance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Skottke, Eva-Maria; Debus, Günter; Wang, Lei; Huestegge, Lynn</p> <p>2014-11-01</p> <p>In the present study, we tested to what extent highly automated convoy <span class="hlt">driving</span> involving small spacing ("platooning") may affect time headway (THW) and standard deviation of lateral position (SDLP) during subsequent manual <span class="hlt">driving</span>. Although many previous studies have reported beneficial effects of automated <span class="hlt">driving</span>, some research has also highlighted potential drawbacks, such as increased speed and reduced THW during the activation of semiautomated <span class="hlt">driving</span> systems. Here, we rather focused on the question of whether switching from automated to manual <span class="hlt">driving</span> may produce unwanted carryover effects on safety-relevant <span class="hlt">driving</span> performance. We utilized a pre-post simulator design to measure THW and SDLP after highly automated <span class="hlt">driving</span> and compared the data with those for a control group (manual <span class="hlt">driving</span> throughout). Our data revealed that THW was reduced and SDLP increased after leaving the automation mode. A closer inspection of the data suggested that specifically the effect on THW is likely due to sensory and/or cognitive adaptation processes. Behavioral adaptation effects need to be taken into account in future implementations of automated convoy systems. Potential application areas of this research comprise automated freight traffic (truck convoys) and the design of driver assistance systems in general. Potential countermeasures against following at short distance as behavioral adaptation should be considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25756846','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25756846"><span>Association between alcohol-impaired <span class="hlt">driving</span> enforcement-related strategies and alcohol-impaired <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sanem, Julia R; Erickson, Darin J; Rutledge, Patricia C; Lenk, Kathleen M; Nelson, Toben F; Jones-Webb, Rhonda; Toomey, Traci L</p> <p>2015-05-01</p> <p>All states in the U.S. prohibit alcohol-impaired <span class="hlt">driving</span> but active law enforcement is necessary for effectively reducing this behavior. Sobriety checkpoints, saturation patrols, open container laws, and media campaigns related to enforcement efforts are all enforcement-related strategies for reducing alcohol-impaired <span class="hlt">driving</span>. We conducted surveys of all state patrol agencies and a representative sample of local law enforcement agencies to assess their use of alcohol-impaired <span class="hlt">driving</span> enforcement-related strategies and to determine the relationship between these enforcement-related strategies and self-reported alcohol-impaired <span class="hlt">driving</span> behavior obtained from the Behavioral Risk Factor Surveillance System. We found that sobriety checkpoints, saturation patrols, and enforcement of open container laws were associated with a lower prevalence of alcohol-impaired <span class="hlt">driving</span> but, more importantly, a combination of enforcement-related strategies was associated with a greater decrease in alcohol-impaired <span class="hlt">driving</span> than any individual enforcement-related activity. In addition, alcohol-impaired <span class="hlt">driving</span> enforcement-related strategies were associated with decreased alcohol-impaired <span class="hlt">driving</span> above and beyond their association with decreased binge drinking. Results suggest law enforcement agencies should give greater priority to using a combination of strategies rather than relying on any one individual enforcement activity. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28115437','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28115437"><span><span class="hlt">Driving</span> and dementia: Efficient approach to <span class="hlt">driving</span> safety concerns in family practice.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Linda; Molnar, Frank</p> <p>2017-01-01</p> <p>To provide primary care physicians with an approach to <span class="hlt">driving</span> safety concerns when older persons present with memory difficulties. The approach is based on an accredited memory clinic training program developed by the Centre for Family Medicine Primary Care Collaborative Memory Clinic. One of the most challenging aspects of dementia care is the assessment of <span class="hlt">driving</span> safety. Drivers with dementia are at higher risk of motor vehicle collisions, yet many drivers with mild dementia might be safely able to continue <span class="hlt">driving</span> for several years. Because safe <span class="hlt">driving</span> is dependent on multiple cognitive and functional skills, clinicians should carefully consider many factors when determining if cognitive concerns affect <span class="hlt">driving</span> safety. Specific findings on corroborated history and office-based cognitive testing might aid in the physician's decisions to refer for comprehensive on-road <span class="hlt">driving</span> evaluation and whether to notify transportation authorities in accordance with provincial reporting requirements. Sensitive communication and a person-centred approach are essential. Primary care physicians must consider many factors when determining if cognitive concerns might affect <span class="hlt">driving</span> safety in older drivers. Copyright© the College of Family Physicians of Canada.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/985019-use-deception-improve-client-honeypot-detection-drive-download-attacks','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/985019-use-deception-improve-client-honeypot-detection-drive-download-attacks"><span>Use of Deception to Improve Client Honeypot Detection of <span class="hlt">Drive</span>-by-Download Attacks</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Popovsky, Barbara; Narvaez Suarez, Julia F.; Seifert, Christian</p> <p>2009-07-24</p> <p>This paper presents the application of deception theory to improve the success of client honeypots at detecting malicious web page attacks from infected servers programmed by online criminals to launch <span class="hlt">drive</span>-by-download attacks. The design of honeypots faces three main challenges: deception, how to design honeypots that seem real systems; counter-deception, techniques used to identify honeypots and hence defeating their deceiving nature; and counter counter-deception, how to design honeypots that deceive attackers. The authors propose the application of a deception model known as the deception planning <span class="hlt">loop</span> to identify the current status on honeypot research, development and deployment. The analysis leadsmore » to a proposal to formulate a landscape of the honeypot research and planning of steps ahead.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EPJC...78..261O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EPJC...78..261O"><span>Charged string <span class="hlt">loops</span> in Reissner-Nordström black hole background</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oteev, Tursinbay; Kološ, Martin; Stuchlík, Zdeněk</p> <p>2018-03-01</p> <p>We study the motion of current carrying charged string <span class="hlt">loops</span> in the Reissner-Nordström black hole background combining the gravitational and electromagnetic field. Introducing new electromagnetic interaction between central charge and charged string <span class="hlt">loop</span> makes the string <span class="hlt">loop</span> equations of motion to be non-integrable even in the flat spacetime limit, but it can be governed by an effective potential even in the black hole background. We classify different types of the string <span class="hlt">loop</span> trajectories using effective potential approach, and we compare the innermost stable string <span class="hlt">loop</span> positions with loci of the charged particle innermost stable orbits. We examine string <span class="hlt">loop</span> small oscillations around minima of the string <span class="hlt">loop</span> effective potential, and we plot radial profiles of the string <span class="hlt">loop</span> oscillation frequencies for both the radial and vertical modes. We construct charged string <span class="hlt">loop</span> quasi-periodic oscillations model and we compare it with observed data from microquasars GRO 1655-40, XTE 1550-564, and GRS 1915+105. We also study the acceleration of current carrying string <span class="hlt">loops</span> along the vertical axis and the string <span class="hlt">loop</span> ejection from RN black hole neighbourhood, taking also into account the electromagnetic interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19333824','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19333824"><span>The relationship between impaired <span class="hlt">driving</span> crashes and beliefs about impaired <span class="hlt">driving</span>: do residents in high crash rate counties have greater concerns about impaired <span class="hlt">driving</span>?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Beck, Kenneth H; Yan, Alice F; Wang, Min Qi; Kerns, Timothy J; Burch, Cynthia A</p> <p>2009-04-01</p> <p>The purpose of this investigation was to examine the relationship between impaired <span class="hlt">driving</span> crashes and public beliefs and concerns about impaired <span class="hlt">driving</span> across each of Maryland's twenty-four counties (including Baltimore City). It was hypothesized that residents of counties that experience higher impaired <span class="hlt">driving</span> crashes would express more concerns about impaired <span class="hlt">driving</span> and perceive more risks about <span class="hlt">driving</span> impaired than residents of counties that have lower rates of impaired <span class="hlt">driving</span>. Data for alcohol impaired <span class="hlt">driving</span> crashes were obtained for the years 2004-2006. These data were compared to public opinion data that was obtained annually by random-digit-dial telephone surveys from 2004 to 2007. Concerns about drunk <span class="hlt">driving</span> as well as perceptions of the likelihood of being stopped by the police if one were to <span class="hlt">drive</span> after having too much to drink were related to counties with higher serious impaired <span class="hlt">driving</span> crash rates, as were perceptions that the police and the legal system were too lenient. Perceptions about the likelihood of being stopped by the police were higher in those counties with more impaired <span class="hlt">driving</span> enforcement activity. Perceptions of concern appear to be shaped more by crash exposure than enforcement activity. Campaigns that address impaired <span class="hlt">driving</span> prevention should substantially increase enforcement, strengthen the adjudication process of impaired drivers, and emphasize the potential seriousness of drinking-<span class="hlt">driving</span> crashes in their promotional activities.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3068882','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3068882"><span>Support for stroke patients in resumption of <span class="hlt">driving</span>: patient survey and <span class="hlt">driving</span> simulator trial</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hitosugi, Masahito; Takehara, Itaru; Watanabe, Shu; Hayashi, Yasufumi; Tokudome, Shogo</p> <p>2011-01-01</p> <p>Background: Encouragement of stroke patients to resume <span class="hlt">driving</span> is important to promote their reintegration into the community. Limited rehabilitation has been performed in this regard, owing to lack of specific knowledge on the part of medical staff. To establish an effective support program for stroke patients who wish to resume <span class="hlt">driving</span>, we propose comprehensive training by medical staff using a <span class="hlt">driving</span> simulator. Methods: A survey of stroke patients admitted to the Tokyo Metropolitan Rehabilitation Hospital was first performed. A questionnaire was sent to 525 patients. Of 218 responses, the answers of 118 patients who had been <span class="hlt">driving</span> before their stroke were analyzed. More than 80% of stroke patients did not obtain enough information about resuming <span class="hlt">driving</span> during their hospital stay, and 38.1% of patients would have liked to have had <span class="hlt">driving</span> training with a simulator. From these results, we set out to determine the effect of <span class="hlt">driving</span> training using a realistic and technically advanced <span class="hlt">driving</span> simulator. Twenty-four stroke patients and 20 healthy controls were included in the study. Results: Repeat training with the simulator resulted in an increased ability to perform braking and an improvement in <span class="hlt">driving</span> ability. The majority of stroke patients who had the mental and physical ability to <span class="hlt">drive</span> a car were likely to be assessed as being able to resume <span class="hlt">driving</span> as a result of the training program. Conclusion: This study indicates that comprehensive support by medical staff and provision of adequate information about resumption of <span class="hlt">driving</span> and the opportunity for training on a <span class="hlt">driving</span> simulator are likely to aid resumption of <span class="hlt">driving</span> by stroke patients, thus enhancing their rehabilitation and social reintegration. PMID:21475633</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-03-10/pdf/2011-5117.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-03-10/pdf/2011-5117.pdf"><span>76 FR 13067 - Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-03-10</p> <p>... and strut forward bulkhead of the forward engine mount and adjacent support structure, and visual... cracked <span class="hlt">hanger</span> fittings, back-up angles, and bulkhead of the forward engine mount, which could lead to failure of the <span class="hlt">hanger</span> fitting and bulkhead and consequent separation of the engine from the airplane...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-07-08/pdf/2010-16606.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-07-08/pdf/2010-16606.pdf"><span>75 FR 39185 - Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-07-08</p> <p>... and torque checks of the <span class="hlt">hanger</span> fittings and strut forward bulkhead of the forward engine mount and... requires repetitive inspections and torque checks of the <span class="hlt">hanger</span> fittings and strut forward bulkhead of the... corrective actions are replacing the fasteners; removing loose fasteners; tightening all Group A [[Page 39187...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2833150','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2833150"><span>Mining protein <span class="hlt">loops</span> using a structural alphabet and statistical exceptionality</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2010-01-01</p> <p>Background Protein <span class="hlt">loops</span> encompass 50% of protein residues in available three-dimensional structures. These regions are often involved in protein functions, e.g. binding site, catalytic pocket... However, the description of protein <span class="hlt">loops</span> with conventional tools is an uneasy task. Regular secondary structures, helices and strands, have been widely studied whereas <span class="hlt">loops</span>, because they are highly variable in terms of sequence and structure, are difficult to analyze. Due to data sparsity, long <span class="hlt">loops</span> have rarely been systematically studied. Results We developed a simple and accurate method that allows the description and analysis of the structures of short and long <span class="hlt">loops</span> using structural motifs without restriction on <span class="hlt">loop</span> length. This method is based on the structural alphabet HMM-SA. HMM-SA allows the simplification of a three-dimensional protein structure into a one-dimensional string of states, where each state is a four-residue prototype fragment, called structural letter. The difficult task of the structural grouping of huge data sets is thus easily accomplished by handling structural letter strings as in conventional protein sequence analysis. We systematically extracted all seven-residue fragments in a bank of 93000 protein <span class="hlt">loops</span> and grouped them according to the structural-letter sequence, named structural word. This approach permits a systematic analysis of <span class="hlt">loops</span> of all sizes since we consider the structural motifs of seven residues rather than complete <span class="hlt">loops</span>. We focused the analysis on highly recurrent words of <span class="hlt">loops</span> (observed more than 30 times). Our study reveals that 73% of <span class="hlt">loop</span>-lengths are covered by only 3310 highly recurrent structural words out of 28274 observed words). These structural words have low structural variability (mean RMSd of 0.85 Å). As expected, half of these motifs display a flanking-region preference but interestingly, two thirds are shared by short (less than 12 residues) and long <span class="hlt">loops</span>. Moreover, half of recurrent motifs exhibit a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20132552','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20132552"><span>Mining protein <span class="hlt">loops</span> using a structural alphabet and statistical exceptionality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Regad, Leslie; Martin, Juliette; Nuel, Gregory; Camproux, Anne-Claude</p> <p>2010-02-04</p> <p>Protein <span class="hlt">loops</span> encompass 50% of protein residues in available three-dimensional structures. These regions are often involved in protein functions, e.g. binding site, catalytic pocket... However, the description of protein <span class="hlt">loops</span> with conventional tools is an uneasy task. Regular secondary structures, helices and strands, have been widely studied whereas <span class="hlt">loops</span>, because they are highly variable in terms of sequence and structure, are difficult to analyze. Due to data sparsity, long <span class="hlt">loops</span> have rarely been systematically studied. We developed a simple and accurate method that allows the description and analysis of the structures of short and long <span class="hlt">loops</span> using structural motifs without restriction on <span class="hlt">loop</span> length. This method is based on the structural alphabet HMM-SA. HMM-SA allows the simplification of a three-dimensional protein structure into a one-dimensional string of states, where each state is a four-residue prototype fragment, called structural letter. The difficult task of the structural grouping of huge data sets is thus easily accomplished by handling structural letter strings as in conventional protein sequence analysis. We systematically extracted all seven-residue fragments in a bank of 93000 protein <span class="hlt">loops</span> and grouped them according to the structural-letter sequence, named structural word. This approach permits a systematic analysis of <span class="hlt">loops</span> of all sizes since we consider the structural motifs of seven residues rather than complete <span class="hlt">loops</span>. We focused the analysis on highly recurrent words of <span class="hlt">loops</span> (observed more than 30 times). Our study reveals that 73% of <span class="hlt">loop</span>-lengths are covered by only 3310 highly recurrent structural words out of 28274 observed words). These structural words have low structural variability (mean RMSd of 0.85 A). As expected, half of these motifs display a flanking-region preference but interestingly, two thirds are shared by short (less than 12 residues) and long <span class="hlt">loops</span>. Moreover, half of recurrent motifs exhibit a significant level of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22364966-fine-structures-overlying-loops-confined-solar-flares','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22364966-fine-structures-overlying-loops-confined-solar-flares"><span>FINE STRUCTURES AND OVERLYING <span class="hlt">LOOPS</span> OF CONFINED SOLAR FLARES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Yang, Shuhong; Zhang, Jun; Xiang, Yongyuan, E-mail: shuhongyang@nao.cas.cn</p> <p>2014-10-01</p> <p>Using the Hα observations from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we focus on the fine structures of three confined flares and the issue why all the three flares are confined instead of eruptive. All the three confined flares take place successively at the same location and have similar morphologies, so can be termed homologous confined flares. In the simultaneous images obtained by the Solar Dynamics Observatory, many large-scale coronal <span class="hlt">loops</span> above the confined flares are clearly observed in multi-wavelengths. At the pre-flare stage, two dipoles emerge near the negative sunspot, and the dipolar patches aremore » connected by small <span class="hlt">loops</span> appearing as arch-shaped Hα fibrils. There exists a reconnection between the small <span class="hlt">loops</span>, and thus the Hα fibrils change their configuration. The reconnection also occurs between a set of emerging Hα fibrils and a set of pre-existing large <span class="hlt">loops</span>, which are rooted in the negative sunspot, a nearby positive patch, and some remote positive faculae, forming a typical three-legged structure. During the flare processes, the overlying <span class="hlt">loops</span>, some of which are tracked by activated dark materials, do not break out. These direct observations may illustrate the physical mechanism of confined flares, i.e., magnetic reconnection between the emerging <span class="hlt">loops</span> and the pre-existing <span class="hlt">loops</span> triggers flares and the overlying <span class="hlt">loops</span> prevent the flares from being eruptive.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018A%26A...613L...3K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018A%26A...613L...3K"><span>Excitation of vertical coronal <span class="hlt">loop</span> oscillations by impulsively driven flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohutova, P.; Verwichte, E.</p> <p>2018-05-01</p> <p>Context. Flows of plasma along a coronal <span class="hlt">loop</span> caused by the pressure difference between <span class="hlt">loop</span> footpoints are common in the solar corona. Aims: We aim to investigate the possibility of excitation of <span class="hlt">loop</span> oscillations by an impulsively driven flow triggered by an enhanced pressure in one of the <span class="hlt">loop</span> footpoints. Methods: We carry out 2.5D magnetohydrodynamic (MHD) simulations of a coronal <span class="hlt">loop</span> with an impulsively driven flow and investigate the properties and evolution of the resulting oscillatory motion of the <span class="hlt">loop</span>. Results: The action of the centrifugal force associated with plasma moving at high speeds along the curved axis of the <span class="hlt">loop</span> is found to excite the fundamental harmonic of a vertically polarised kink mode. We analyse the dependence of the resulting oscillations on the speed and kinetic energy of the flow. Conclusions: We find that flows with realistic speeds of less than 100 km s-1 are sufficient to excite oscillations with observable amplitudes. We therefore propose plasma flows as a possible excitation mechanism for observed transverse <span class="hlt">loop</span> oscillations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/1433058','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/1433058"><span>Dementia and <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>O'Neill, D; Neubauer, K; Boyle, M; Gerrard, J; Surmon, D; Wilcock, G K</p> <p>1992-04-01</p> <p>Many European countries test cars, but not their drivers, as they age. There is evidence to suggest that human factors are more important than vehicular factors as causes of motor crashes. The elderly also are involved in more accidents per distance travelled than middle-aged drivers. As the UK relies on self-certification of health by drivers over the age of 70 years, we examined the <span class="hlt">driving</span> practices of patients with dementia attending a Memory Clinic. Nearly one-fifth of 329 patients with documented dementia continued to <span class="hlt">drive</span> after the onset of dementia, and impaired <span class="hlt">driving</span> ability was noted in two-thirds of these. Their families experienced great difficulty in persuading patients to stop <span class="hlt">driving</span>, and had to invoke outside help in many cases. Neuropsychological tests did not help to identify those who drove badly while activity of daily living scores were related to <span class="hlt">driving</span> ability. These findings suggest that many patients with dementia <span class="hlt">drive</span> in an unsafe fashion after the onset of the illness. The present system of self-certification of health by the elderly for driver-licensing purposes needs to be reassessed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1294722','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1294722"><span>Dementia and <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>O'Neill, D; Neubauer, K; Boyle, M; Gerrard, J; Surmon, D; Wilcock, G K</p> <p>1992-01-01</p> <p>Many European countries test cars, but not their drivers, as they age. There is evidence to suggest that human factors are more important than vehicular factors as causes of motor crashes. The elderly also are involved in more accidents per distance travelled than middle-aged drivers. As the UK relies on self-certification of health by drivers over the age of 70 years, we examined the <span class="hlt">driving</span> practices of patients with dementia attending a Memory Clinic. Nearly one-fifth of 329 patients with documented dementia continued to <span class="hlt">drive</span> after the onset of dementia, and impaired <span class="hlt">driving</span> ability was noted in two-thirds of these. Their families experienced great difficulty in persuading patients to stop <span class="hlt">driving</span>, and had to invoke outside help in many cases. Neuropsychological tests did not help to identify those who drove badly while activity of daily living scores were related to <span class="hlt">driving</span> ability. These findings suggest that many patients with dementia <span class="hlt">drive</span> in an unsafe fashion after the onset of the illness. The present system of self-certification of health by the elderly for driver-licensing purposes needs to be reassessed. PMID:1433058</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19068291','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19068291"><span>Dialling and <span class="hlt">driving</span>: factors influencing intentions to use a mobile phone while <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Walsh, Shari P; White, Katherine M; Hyde, Melissa K; Watson, Barry</p> <p>2008-11-01</p> <p>Despite being identified as an unsafe (and, in some jurisdictions, illegal) <span class="hlt">driving</span> practice, the psychological factors underlying people's decision to use their mobile phone while <span class="hlt">driving</span> have received little attention. The present study utilised the theory of planned behaviour (TPB) to examine the role of attitudes, norms, control factors, and risk perceptions, in predicting people's intentions to use their mobile phone while <span class="hlt">driving</span>. We examined the predictors of intentions to use a mobile phone while <span class="hlt">driving</span> in general, and for calling and text messaging in 4 scenarios differing in descriptions of vehicle speed and time pressure. There was some support for the TPB given that attitudes consistently predicted intentions to <span class="hlt">drive</span> while using a mobile phone and that pressure from significant others (norms) determined some phone use while <span class="hlt">driving</span> intentions, although less support was found for the role of perceptions of control. Risk was not generally predictive of safer <span class="hlt">driving</span> intentions. These findings indicate that different factors influence each form of mobile phone use while <span class="hlt">driving</span> and, hence, a multi-strategy approach is likely to be required to address the issue.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24913481','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24913481"><span>Relationships between frequency of <span class="hlt">driving</span> under the influence of cannabis, self-reported reckless <span class="hlt">driving</span> and risk-taking behavior observed in a <span class="hlt">driving</span> simulator.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bergeron, Jacques; Paquette, Martin</p> <p>2014-06-01</p> <p>The role of cannabis consumption in traffic crashes is unclear and the causal link between cannabis and collisions is still to be demonstrated. While cannabis use is very likely to impair <span class="hlt">driving</span> ability, there is as yet no overwhelming evidence that cannabis use in isolation contributes more to collisions than other characteristics inherent to cannabis users. As noted in a growing body of literature, individuals <span class="hlt">driving</span> under the influence of cannabis (DUIC) seem to exhibit a general reckless <span class="hlt">driving</span> style putting them at higher risk to be involved in traffic crashes. This study aims at investigating the relationship between self-reported DUIC and reckless <span class="hlt">driving</span> by means of self-reported measures and direct observations made in a <span class="hlt">driving</span> simulator. Participants (n=72) were required to be between 18 and 25 years of age, to hold a valid driver's license, and to <span class="hlt">drive</span> at least twice a week. They completed standard <span class="hlt">driving</span> simulation tasks recreating everyday on-road trivial conditions. Results show that people admitting that they commit more real-life dangerous <span class="hlt">driving</span> behaviors reached higher maximum speed and demonstrated more reckless <span class="hlt">driving</span> behaviors on the <span class="hlt">driving</span> simulation tasks. Self-reported DUIC is associated with a risky <span class="hlt">driving</span> style including a broad range of reckless on-road behaviors and support the problem <span class="hlt">driving</span> behavior theory. Moreover, beyond confounding factors, both self-report DUIC and observed dangerous behaviors are associated with real-life traffic violations. Since DUIC appears to be related to an overall reckless style of <span class="hlt">driving</span>, it is proposed that public safety policies should be more holistic, simultaneously targeting multiple on-road dangerous behaviors for intervention. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MSSP..105...68Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MSSP..105...68Z"><span>Optimal control of mode transition for four-wheel-<span class="hlt">drive</span> hybrid electric vehicle with dry dual-clutch transmission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Zhiguo; Lei, Dan; Chen, Jiayi; Li, Hangyu</p> <p>2018-05-01</p> <p>When the four-wheel-<span class="hlt">drive</span> hybrid electric vehicle (HEV) equipped with a dry dual clutch transmission (DCT) is in the mode transition process from pure electrical rear wheel <span class="hlt">drive</span> to front wheel <span class="hlt">drive</span> with engine or hybrid <span class="hlt">drive</span>, the problem of vehicle longitudinal jerk is prominent. A mode transition robust control algorithm which resists external disturbance and model parameter fluctuation has been developed, by taking full advantage of fast and accurate torque (or speed) response of three electrical power sources and getting the clutch of DCT fully involved in the mode transition process. Firstly, models of key components of driveline system have been established, and the model of five-degrees-of-freedom vehicle longitudinal dynamics has been built by using a Uni-Tire model. Next, a multistage optimal control method has been produced to realize the decision of engine torque and clutch-transmitted torque. The sliding-mode control strategy for measurable disturbance has been proposed at the stage of engine speed dragged up. Meanwhile, the double tracking control architecture that integrates the model calculating feedforward control with H∞ robust feedback control has been presented at the stage of speed synchronization. Finally, the results from Matlab/Simulink software and hardware-in-the-<span class="hlt">loop</span> test both demonstrate that the proposed control strategy for mode transition can not only coordinate the torque among different power sources and clutch while minimizing vehicle longitudinal jerk, but also provide strong robustness to model uncertainties and external disturbance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22766131','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22766131"><span>Cognitive impairment and <span class="hlt">driving</span> safety.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eby, David W; Molnar, Lisa J</p> <p>2012-11-01</p> <p>As the populations of many countries continue to age, cognitive impairment will likely become more common. Individuals with cognitive impairment pose special challenges for families, health professionals, <span class="hlt">driving</span> safety professionals, and the larger community, particularly if these older adults depend on <span class="hlt">driving</span> as their primary means of community mobility. It is vital that we continue to extend our knowledge about the <span class="hlt">driving</span> behavior of individuals' with cognitive impairment, as well as try to develop effective means of screening and assessing these individuals for fitness to <span class="hlt">drive</span> and help facilitate their transition to non-<span class="hlt">driving</span> when appropriate. This special issue is intended to provide researchers and practitioners an opportunity to present the most recent research findings on <span class="hlt">driving</span>-related issues among older adults with cognitive impairment. The issue contains 11 original contributions from seven countries. The topics covered by these papers are: crash risks; screening, assessment, and fitness to <span class="hlt">drive</span>; <span class="hlt">driving</span> performance using a <span class="hlt">driving</span> simulator; and <span class="hlt">driving</span> behaviors and <span class="hlt">driving</span>-related decisions of people with cognitive impairments. Copyright © 2012. Published by Elsevier Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20196300','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20196300"><span>Text messaging during simulated <span class="hlt">driving</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drews, Frank A; Yazdani, Hina; Godfrey, Celeste N; Cooper, Joel M; Strayer, David L</p> <p>2009-10-01</p> <p>This research aims to identify the impact of text messaging on simulated <span class="hlt">driving</span> performance. In the past decade, a number of on-road, epidemiological, and simulator-based studies reported the negative impact of talking on a cell phone on <span class="hlt">driving</span> behavior. However, the impact of text messaging on simulated <span class="hlt">driving</span> performance is still not fully understood. Forty participants engaged in both a single task (<span class="hlt">driving</span>) and a dual task (<span class="hlt">driving</span> and text messaging) in a high-fidelity <span class="hlt">driving</span> simulator. Analysis of <span class="hlt">driving</span> performance revealed that participants in the dual-task condition responded more slowly to the onset of braking lights and showed impairments in forward and lateral control compared with a <span class="hlt">driving</span>-only condition. Moreover, text-messaging drivers were involved in more crashes than drivers not engaged in text messaging. Text messaging while <span class="hlt">driving</span> has a negative impact on simulated <span class="hlt">driving</span> performance. This negative impact appears to exceed the impact of conversing on a cell phone while <span class="hlt">driving</span>. The results increase our understanding of driver distraction and have potential implications for public safety and device development.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26042818','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26042818"><span>State all-driver distracted <span class="hlt">driving</span> laws and high school students' texting while <span class="hlt">driving</span> behavior.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qiao, Nan; Bell, Teresa Maria</p> <p>2016-01-01</p> <p>Texting while <span class="hlt">driving</span> is highly prevalent among adolescents and young adults in the United States. Texting while <span class="hlt">driving</span> can significantly increase the risk of road crashes and is associated with other risky <span class="hlt">driving</span> behaviors. Most states have enacted distracted <span class="hlt">driving</span> laws to prohibit texting while <span class="hlt">driving</span>. This study examines effects of different all-driver distracted <span class="hlt">driving</span> laws on texting while <span class="hlt">driving</span> among high school students. High school student data were extracted from the 2013 National Youth Risk Behavior Survey. Distracted <span class="hlt">driving</span> law information was collected from the National Conference of State Legislatures. The final sample included 6,168 high school students above the restricted <span class="hlt">driving</span> age in their states and with access to a vehicle. Logistic regression was applied to estimate odds ratios of laws on texting while <span class="hlt">driving</span>. All-driver text messaging bans with primary enforcement were associated with a significant reduction in odds of texting while <span class="hlt">driving</span> among high school students (odds ratio = 0.703; 95% confidence interval, 0.513-0.964), whereas all-driver phone use bans with primary enforcement did not have a significant association with texting while <span class="hlt">driving</span> (odds ratio = 0.846; 95% confidence interval, 0.501-1.429). The findings indicate that all-driver distracted <span class="hlt">driving</span> laws that specifically target texting while <span class="hlt">driving</span> as opposed to all types of phone use are effective in reducing the behavior among high school students.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20380903','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20380903"><span>Using <span class="hlt">driving</span> simulators to assess <span class="hlt">driving</span> safety.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boyle, Linda Ng; Lee, John D</p> <p>2010-05-01</p> <p>Changes in drivers, vehicles, and roadways pose substantial challenges to the transportation safety community. Crash records and naturalistic <span class="hlt">driving</span> data are useful for examining the influence of past or existing technology on drivers, and the associations between risk factors and crashes. However, they are limited because causation cannot be established and technology not yet installed in production vehicles cannot be assessed. <span class="hlt">Driving</span> simulators have become an increasingly widespread tool to understand evolving and novel technologies. The ability to manipulate independent variables in a randomized, controlled setting also provides the added benefit of identifying causal links. This paper introduces a special issue on simulator-based safety studies. The special issue comprises 25 papers that demonstrate the use of <span class="hlt">driving</span> simulators to address pressing transportation safety problems and includes topics as diverse as neurological dysfunction, work zone design, and driver distraction. Copyright (c) 2010 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090002582','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090002582"><span>Similarity Metrics for Closed <span class="hlt">Loop</span> Dynamic Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whorton, Mark S.; Yang, Lee C.; Bedrossian, Naz; Hall, Robert A.</p> <p>2008-01-01</p> <p>To what extent and in what ways can two closed-<span class="hlt">loop</span> dynamic systems be said to be "similar?" This question arises in a wide range of dynamic systems modeling and control system design applications. For example, bounds on error models are fundamental to the controller optimization with modern control design methods. Metrics such as the structured singular value are direct measures of the degree to which properties such as stability or performance are maintained in the presence of specified uncertainties or variations in the plant model. Similarly, controls-related areas such as system identification, model reduction, and experimental model validation employ measures of similarity between multiple realizations of a dynamic system. Each area has its tools and approaches, with each tool more or less suited for one application or the other. Similarity in the context of closed-<span class="hlt">loop</span> model validation via flight test is subtly different from error measures in the typical controls oriented application. Whereas similarity in a robust control context relates to plant variation and the attendant affect on stability and performance, in this context similarity metrics are sought that assess the relevance of a dynamic system test for the purpose of validating the stability and performance of a "similar" dynamic system. Similarity in the context of system identification is much more relevant than are robust control analogies in that errors between one dynamic system (the test article) and another (the nominal "design" model) are sought for the purpose of bounding the validity of a model for control design and analysis. Yet system identification typically involves open-<span class="hlt">loop</span> plant models which are independent of the control system (with the exception of limited developments in closed-<span class="hlt">loop</span> system identification which is nonetheless focused on obtaining open-<span class="hlt">loop</span> plant models from closed-<span class="hlt">loop</span> data). Moreover the objectives of system identification are not the same as a flight test and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.nrel.gov/transportation/drive.html','SCIGOVWS'); return false;" href="https://www.nrel.gov/transportation/drive.html"><span><span class="hlt">DRIVE</span>: <span class="hlt">Drive</span>-Cycle Rapid Investigation, Visualization, and Evaluation</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>specialized <em>statistical</em> clustering <em>methods</em>. <em>The</em> duration of these representative <span class="hlt">drive</span> cycles, which aim to , <span class="hlt">DRIVE</span> can benefit a variety of users. <em>For</em> example: Fleet managers can use <em>the</em> tool to make educated investment decisions by determining, in advance, <em>the</em> payback period <em>for</em> a given technology. Vehicle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005NIMPB.235...40G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005NIMPB.235...40G"><span>Second-order electron self-energy <span class="hlt">loop-after-loop</span> correction for low- Z hydrogen-like ions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goidenko, Igor; Labzowsky, Leonti; Plunien, Günter; Soff, Gerhard</p> <p>2005-07-01</p> <p>The second-order electron self-energy <span class="hlt">loop-after-loop</span> correction is investigated for hydrogen-like ions in the region of low nuclear charge numbers Z. Both irreducible and reducible parts of this correction are evaluated for the 1s1/2-state within the Fried-Yennie gauge. We confirm the result obtained first by Mallampalli and Sapirstein. The reducible part of this correction is evaluated numerically for the first time and it is consistent with the corresponding analytical αZ-expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=supernova&id=EJ362816','ERIC'); return false;" href="https://eric.ed.gov/?q=supernova&id=EJ362816"><span>The Cygnus <span class="hlt">Loop</span>: An Older Supernova Remnant.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Straka, William</p> <p>1987-01-01</p> <p>Describes the Cygnus <span class="hlt">Loop</span>, one of brightest and most easily studied of the older "remnant nebulae" of supernova outbursts. Discusses some of the historical events surrounding the discovery and measurement of the Cygnus <span class="hlt">Loop</span> and makes some projections on its future. (TW)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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