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Sample records for 22-250 fampridine ac

  1. Sustained-release fampridine in Multiple Sclerosis.

    Hadavi, S; Baker, M D; Dobson, R

    2014-01-01

    Sustained-release fampridine, a slow release formulation of 4-aminopryridine, is a voltage-dependent potassium channel blocker licensed for the treatment of walking difficulties in multiple sclerosis (MS). Studies have demonstrated that approximately one-third of MS patients respond with a clear benefit to their walking speed. Sustained-release Fampridine is not currently available on the National Health Service (NHS), although it has been approved by the Food and Drug Administration (FDA) in the USA and European Medicine Agency (EMA). It appears to have an acceptable adverse event profile, with data from open-label extension studies now becoming available. Concerns have been raised that the use of fampridine may increase the risk of seizures, which were seen at higher rates in patients treated with high doses of sustained-release fampridine. The rate of seizures in those patients on lower doses has not been found to be significantly increased. There are significant barriers at present to the widespread use of fampridine in the UK, which have limited its use in clinical practice to date. Patients with MS are in need of interventions to improve walking and many clinicians feel that this drug may have a role in the symptomatic management of MS. PMID:25877967

  2. Changes in cognition, arm function and lower body function after slow-release Fampridine treatment

    Jensen, H; Ravnborg, M; Mamoei, S;

    2014-01-01

    meaningful change on the SSST compared with 25.7% on the T25FW. The response to treatment with SR Fampridine did not correlate with age, sex, Expanded Disability Status Scale and disease duration. CONCLUSION: SR Fampridine treatment has significant effects on different domains including upper and lower body...

  3. Fampridine-PR (prolonged released 4-aminopyridine) is not effective in patients with inflammatory demyelination of the peripheral nervous system.

    Leussink, Verena-Isabell; Stettner, Mark; Warnke, Clemens; Hartung, Hans-Peter

    2016-06-01

    Fampridine-PR is a voltage-gated potassium channel inhibitor potentially improving nerve conduction in demyelinated axons. Based on its established clinical efficacy in patients with demyelination in the central nervous system, we assessed if fampridine-PR is also effective in patients with inflammatory demyelination of the peripheral nerve. In this small open-label study, 10 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) were treated with fampridine-PR 10 mg BID for 28 days and assessed clinically as well as by nerve conduction studies. In this study, Fampridine-PR failed to improve CIDP based on clinical measures and nerve conduction studies. Our findings suggest that Fampridine-PR appears to be ineffective in demyelinating polyneuropathies. These observations may indicate a more complex mode of action beyond improving action potential conduction in demyelinated axons. PMID:26968589

  4. Distribution-based estimates of minimum clinically important difference in cognition, arm function and lower body function after slow release-fampridine treatment of patients with multiple sclerosis

    Jensen, H B; Mamoei, Sepehr; Ravnborg, M;

    2016-01-01

    OBJECTIVE: To provide distribution-based estimates of the minimal clinical important difference (MCID) after slow release fampridine treatment on cognition and functional capacity in people with MS (PwMS). METHOD: MCID values were determined after SR-Fampridine treatment in 105 PwMS. Testing...

  5. Assessing the long-term clinical benefit of prolonged-release fampridine tablets in a real-world setting: a review of 67 cases

    Prugger M

    2013-10-01

    Full Text Available Michael Prugger, Thomas Berger Neuroimmunology and Multiple Sclerosis Clinic and Research Unit, Clinical Department of Neurology, Innsbruck Medical University, Innsbruck, Austria Purpose: To assess the long-term effects of prolonged-release (PR fampridine tablets (dalfampridine extended release in clinical practice in patients with multiple sclerosis (MS with walking impairment. Patients and methods: MS patients with walking impairment deemed candidates for treatment with PR-fampridine tablets were included in this case series. Clinical assessments included the Expanded Disability Status Scale (EDSS, Timed 25-Foot Walk (T25FW, 12-item Multiple Sclerosis Walking Scale (MSWS-12, EuroQoL-5D, and the Fatigue Severity Scale (FSS. The T25FW was videotaped at each visit. Assessments were performed at baseline and after 4 weeks of treatment with PR-fampridine tablets 10 mg twice daily. Clinical benefit of treatment was defined as any improvement in T25FW or MSWS-12 score at 4 weeks. Patients who demonstrated clinical benefit continued treatment and were assessed at 3 and 6 months. Results: Among all patients (N = 67; mean MS duration, 16.5 years; mean EDSS score, 4.8; mean T25FW, 13.9 seconds, 65, 52, and 48 completed the 4-week, 3-month, and 6-month visits, respectively. After 4 weeks, 50.7% and 32.8% of patients walked ≥10% and ≥20% faster, respectively; and in 65.7% of patients, MSWS-12 scores improved. Three patients experienced adverse events (nausea, n = 2, insomnia, n = 1 that resulted in discontinuation of treatment. After 6 months, 38.8% and 16.4% of patients walked ≥10% and ≥20% faster versus baseline, respectively; and in 59.7% of patients, MSWS-12 scores improved. Among patients who demonstrated clinical benefit of treatment at 6 months, FSS scores improved on average by 1 point and MSWS-12 scores by 10 points. Three case studies showing different outcomes of PR-fampridine treatment are detailed with a visual depiction of the changes

  6. Comparison of LC-UV and LC-MS methods for simultaneous determination of teriflunomide, dimethyl fumarate and fampridine in human plasma: application to rat pharmacokinetic study.

    Suneetha, A; Raja, Rajeswari K

    2016-09-01

    This study describes a comparison between LC-UV and LC-MS method for the simultaneous analyses of a few disease-modifying agents of multiple sclerosis. Quantitative determination of fampridine (FAM), teriflunomide (TFM) and dimethyl fumarate (DMF) was performed in human plasma with the recovery values in the range of 85-115%. A reversed-phase high-performance liquid chromatography (HPLC) with UV as well as MS detection is used. The method utilizes an XBridge C18 silica column and a gradient elution with mobile phase consisting of ammonium formate and acetonitrile at a flow rate of 0.5 mL min(-1) . The method adequately resolves FAM, TFM and DMF within a run time of 15 min. Owing to low molecular weights, the estimation of DMF and FAM is more versatile in UV than MS detection. With LC-UV, the detection limits of FAM, TFM and DMF were 0.1, 0.05, 0.05 μg and the quantification limit for all the analytes was 1 μg. With LC-MS, the detection and quantification limits for all of the analytes were 1 and 5 ng, respectively. The two techniques were completely validated and shown to be reproducible and sensitive. They were applied to a pharmacokinetic study in rats by a single oral dose. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26849839

  7. ACAC Converters for UPS

    Rusalin Lucian R. Păun

    2008-05-01

    Full Text Available This paper propose a new control technique forsingle – phase ACAC converters used for a on-line UPSwith a good dynamic response, a reduced-partscomponents, a good output characteristic, a good powerfactorcorrection(PFC. This converter no needs anisolation transformer. A power factor correction rectifierand an inverter with the proposed control scheme has beendesigned and simulated using Caspoc2007, validating theconcept.

  8. AC power supply systems

    An ac power supply system includes a rectifier fed by a normal ac supply, and an inverter connected to the rectifier by a dc link, the inverter being effective to invert the dc output of the receiver at a required frequency to provide an ac output. A dc backup power supply of lower voltage than the normal dc output of the rectifier is connected across the dc link such that the ac output of the rectifier is derived from the backup supply if the voltage of the output of the inverter falls below that of the backup supply. The dc backup power may be derived from a backup ac supply. Use in pumping coolant in nuclear reactor is envisaged. (author)

  9. AcEST: DK950971 [AcEST

    Full Text Available optera acutorost... 37 0.66 tr|B1ACS6|B1ACS6_BALBN DMP1 (Fragment) OS=Balaenoptera ...bonaerens... 37 0.66 tr|B1ACS5|B1ACS5_BALED DMP1 (Fragment) OS=Balaenoptera edeni... GN=... 37 0.66 tr|B1ACS4|B1ACS4_BALBO DMP1 (Fragment) OS=Balaenoptera borealis ... 37 0.66 tr|B1ACS3|B1ACS3..._BALMU DMP1 (Fragment) OS=Balaenoptera musculus ... 37 0.86 tr|B1ACS1|B1ACS1_MEGNO DMP1 (Fragment) OS=Megapt...1ACS2_BALPH DMP1 (Fragment) OS=Balaenoptera physalus ... 37 1.1 tr|B1ACT6|B1ACT6_MESPE DMP1 (Fragment) OS=Me

  10. AC1 Wing

    Adrian DOBRE

    2010-03-01

    Full Text Available The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  11. AC1 Wing

    Adrian DOBRE

    2010-01-01

    The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  12. ac bidirectional motor controller

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  13. AC/RF Superconductivity

    Ciovati, Gianluigi [JLAB

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  14. AC/RF Superconductivity

    Ciovati, G.

    2015-01-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  15. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity

  16. Hermetisk AC-Krets

    Hirsch, Carl; Smirnoff, Alexander

    2007-01-01

    Under sex månader våren 2007 har ett samarbete mellan Volvo Lastvagnar och två studenter från KTH, inriktning Integrerad produktutveckling vid institutionen för maskinkonstruktion, pågått i form av ett examensarbete på 20 poäng. Dagens AC-system i Volvos lastbilar avger 20-40 g/år av köldmediet R134a som är en kraftfull växthusgas. Detta sker främst genom diffusion via slangar och tätningsmaterial. Syftet med detta examensarbete är att ta fram förslag på tekniska lösningar på ett nytt AC-syst...

  17. High performance AC drives

    Ahmad, Mukhtar

    2010-01-01

    This book presents a comprehensive view of high performance ac drives. It may be considered as both a text book for graduate students and as an up-to-date monograph. It may also be used by R & D professionals involved in the improvement of performance of drives in the industries. The book will also be beneficial to the researchers pursuing work on multiphase drives as well as sensorless and direct torque control of electric drives since up-to date references in these topics are provided. It will also provide few examples of modeling, analysis and control of electric drives using MATLAB/SIMULIN

  18. Superconducting ac cable

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.)

  19. Ac Hybrid Charge Controller

    Shalini S. Durgam

    2015-03-01

    Full Text Available One of the primary needs for socio-economic development in any nation in the world is the provision of reliable electricity supply systems with lower carbon footprint levels. The purpose of this work is the development of a hybrid Power system that harnesses the renewable energy in sun and electricity to generate electricity. The working model can able to run on dual mode- solar and electricity. It can also be driven independently either by solar or electricity. The battery can be charge from solar panel (40W or by power supply. The household single phase A.C. power supply of 230V is converted into 12V D.C. using step down transformer and rectifying circuit. The working model can achieve energy saving, low carbon emission, environmental protection for the upcoming future of human life.

  20. AcEST: BP920072 [AcEST

    Full Text Available YMU001_000132_F11 525 Adiantum capillus-veneris mRNA. clone: YMU001_000132_F11. BP920072 - Show ... YGMYGEGEKALETFADMEKSGIVPDSVVFIAII 617 Query: 139 NACSR SCLFHECHSYFEAMSTHHGIVPCLEHHSCVV 32 ACS S L E + FE M ... KLMTRDVVSWNTLIAGYAQVGQNEGLFCTFSDMLGQRVKPDLITFVIVLNACSR ... 125 VF+ + +D VSWN++I+GY Q G F M+ + D IT++++++ +R S ... YGVHGYGKKAIQIFEEMLANGASP 384 Query: 166 DLITFVIVLNACSR SCLFHECHSYFEAMSTHHGIVPCLEHHSCVV 32 +TFV VL ACS L E ... KLMTRDVVSWNTLIAGYAQVGQNEGLFCTFSDMLGQRVKPDLITFVIVLNACSR S 122 +VFDK R + WN L G E + + M V+ D T+ VL AC S Sbjc ...

  1. Induction Motor Control through AC/DC/AC Converters

    Elfadili, Abderrahim; Giri, Fouad; Ouadi, Hamid; El Magri, Abdelmounime; Dugard, Luc; Abouloifa, Abdelmajid

    2010-01-01

    We consider the problem of controlling inductions motors driven through AC/DC rectifiers and DC/AC inverters. The control objectives are threefold: (i) forcing the motor speed to track a reference signal, (ii) regulating the DC Link voltage, (iii) assuring a satisfactory power factor correction (PFC) with respect to the power supply net. First, a nonlinear model of the whole controlled system is developed in the Park-coordinates. Then, a nonlinear multi-loop controller is synthesized using th...

  2. AcEST: BP920905 [AcEST

    Full Text Available EM + + D ++S L AC Sbjct: 374 NSAYKLFERMPKKNVVAWNAIISGYSQHGHPHEALALFIEMQAQGIKPDSFAIVSVLPAC 433 Query: 71 SHSSTLNDGKLIHFYILMNNFE...EM++ ++ + V + S L +C Sbjct: 255 SSERIFEKIAKKNAVSWTAMISSYNRGEFSEKALRSFSEMIKSGIEPNLVTLYSVLSSCG 314 Query: 68 HSSTLNDGKLIHFYILMNNFE...VVVMSCLKACS 69 ++ +F RRD VTW A+I GYA HG E A+ LF+ M+ EN+ + V +S L+AC+ Sbjct: 656 DSRLMFEKSLRRDFVTWNAMICGYAHHGKGEEAIQLFERMILEN...ELEKMHNKRLQEMCVSWNSIISGYVMKEQSEDAQMLFTRMME 596 Query: 122 ENVDTDGVVVMSCLKACSHSSTLNDGKLIHFYILMNNFE ...FCEADT-NVITWNAMIASYVHCEQSEKAIALFDRMVSENFKPSSITLVTLLMAC 543 Query: 71 SHSSTLNDGKLIHFYILMNNFEL 3 ++ +L G++

  3. AcEST: DK950147 [AcEST

    Full Text Available TST38A01NGRL0007_O05 706 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0007_O05. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  4. AcEST: DK959344 [AcEST

    Full Text Available TST39A01NGRL0004_G23 714 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0004_G23. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  5. AcEST: DK949716 [AcEST

    Full Text Available TST38A01NGRL0006_L20 613 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0006_L20. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  6. AC drives for industrial plants. Plant kudoyo AC drive sochi

    Miyazaki, M.; Shibata, M.; Yamada, S. (Toshiba Corp., Tokyo (Japan))

    1992-08-01

    Features and product series of AC drives for industrial plants were outlined. Configurations and features of various types of AC drives were briefly discussed which are put into market to meet various requirements for industrial plants and wide ranges of output voltage and capacity. The following product series were outlined; the power bipolar transistor inverter for 3.5-600 kVA in output capacity, IGBT inverter for AC 400 V in output voltage and 1,000 kVA or less, GTO inverter for AC 600 V and 700-2,000 kVA, and cycloconverter for AC 1,000-3,000 V and 1,000 kW-20 MW. The following subjects were outlined as current technical trends of AC drives for industrial plants; increasing in capacity of voltage-source PWM inverters, downsizing of converters through highly efficient cooling and highly dense mounting, spreading of sensorless vector controls, and development of high-voltage large-capacity PWM inverters. 6 figs., 2 tabs.

  7. AcEST: DK955197 [AcEST

    Full Text Available TST39A01NGRL0022_H07 532 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0022_H07. 5' end seq ... KDEVTALPLLK 192 Query: 194 RFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLRARF 373 R+ F +AC+L S ... KDEVMALPLLK 192 Query: 194 RFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLRARF 373 R+ F +AC+L S ... KDEVKVLP 189 Query: 185 LMKRFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLR 364 L++ F IA L + +Q+ ... KDEATVLP 177 Query: 185 LMKRFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLR 364 L+K F +A L E+ QE ...

  8. AcEST: BP915640 [AcEST

    Full Text Available YMU001_000074_A01 462 Adiantum capillus-veneris mRNA. clone: YMU001_000074_A01. BP915640 CL3685C ... y: 462 GPLILRACLVYMQGAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI IHRLIAAFKEVG 283 G IL+AC YM+G +GSL +D V ++VGF+LMLAK ... : 1032 GYYILKACDAYMKGYLIGSLTKDASVIDERSS-ANSTSVGFKLMLAKI APKLFSALSEVG 1090 Query: 282 AYCDAYE 262 A C+ ++ Sb ... uery: 453 ILRACLVYMQGAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI IHRLIAAFKEVGAYC 274 +L AC YM+G PVGS A G ST GF++ML+K ... ame = -1 Query: 423 GAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI I----HRLIAAFKEVGAYCD 271 G P+ L D +S GK + S RL + L+ ...

  9. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Rakan Kh Antar

    2013-05-01

    Full Text Available    This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.

  10. Nuclear structure of $^{231}$Ac

    Boutami, R; Mach, H; Kurcewicz, W; Fraile, L M; Gulda, K; Aas, A J; García-Raffi, L M; Løvhøiden, G; Martínez, T; Rubio, B; Taín, J L; Tengblad, O

    2008-01-01

    The low-energy structure of 231Ac has been investigated by means of gamma ray spectroscopy following the beta-decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  11. AcEST: BP920800 [AcEST

    Full Text Available DLNLALQVHSRMVRFGFNAEVEACGALINMYGKCGKVLYAQRVFDDT 298 Query: 206 RQQDVISWNDIISACAQRGHGTEALENFSQMLHEGIVPNSMTFTSVMQA---CNSIEGG...G L +A S F ++ +D+ISW +I +Q EA+ F Sbjct: 217 SEKNEATSNCLINGYMGLGNLEQAESLFNQMPVKDIISWTTMIKGYSQNKRYREAIAVFY 276 Query: 119 QMLHEG...EKAWRIFDGVSCKNLPSWNAIITGCVQGGLLEEAIDLYRHMK 281 Query: 110 HEGIVPNSMTFTSVMQAC---NSIEGGR 36 + + PN +T +V+ AC +...N IIS AQ G +EA+E ++ M Sbjct: 383 DITIGNAVVVMYAKLGLVDSARAVFNWLPNTDVISWNTIISGYAQNGFASEAIEMYNIME 442 Query: 110 HEG...EIDLGEQIHSLSVKTGFESDMYVSGVLIDMYSKYGWLEKARRVLEML 406 Query: 206 RQQDVISWNDIISACAQRGHGTEALENFSQMLHEGIVPNSMTFTSVMQACNSIEGG

  12. AcEST: DK945549 [AcEST

    Full Text Available AGGCGATTTCATCTTTTCTGAGAACCCTGATTTTGTGATTGTGTAATTACA ACTGTGGAACAGAAGGATGAGAAGTCTACTGACACAACAAGATATCTCTGGAGAGGAGA...A AATTGAGAAGGTTTGAGTTCTCAACAATGGGCTATGAGGCAATAATGGGAAGGCACCGAT TGTGGGCTTGTATAGGTTTTGAC...LCTG 239 L++R+LRR + + ++ G AC+ DP +P PLC+G Sbjct: 108 LQQRELRRKLLADSGALNTNSVNGPRNWKACVQQDPSSRPGTPLCSG 154 >sp|A6UUY8|RNZ_META3...49 Tissue type young leaves Developmental stage sporophyte Contig ID CL454Contig1 Sequence GATGAGCGA...CCACCTGTGCAACCGTCAGCGCCTTTGTGCACTGGTG CAATGTCCTGTGGTTACCTTGTTTGGAATCTTAATTGTTCTCATGTAT

  13. AcEST: BP917632 [AcEST

    Full Text Available YMU001_000103_D10 554 Adiantum capillus-veneris mRNA. clone: YMU001_000103_D10. BP917632 - Show ... YSKCKIHQKALELLVLML 154 Query: 466 KDSLEPDEVTYLNVLKACARE EDLKV 543 +D++ P+ TY +VL++C D+++ Sbjct: 155 RDNVRPN ... 185 Query: 415 GHSDSS--KEALKLLTQMRKDSLEPDEVTYLNVLKACARE EDLK 540 + EA KL +M+ ++ PDE+ N++ AC R +++ Sbjct: 18 ...

  14. AcEST: DK961189 [AcEST

    Full Text Available OS=A... 127 7e-29 sp|Q94B08|GCP1_ARATH Germination-specific cysteine protease 1 OS... 125 2e-28 sp|P00785|AC...IRNSWGLNWGDSGYVKLQRNIDDPFGKCGIAMMPSYP 347 >sp|Q94B08|GCP1_ARATH Germination-specific cysteine protease 1 OS=

  15. AcEST: DK946687 [AcEST

    Full Text Available YMU02A01NGRL0013_G11 544 Adiantum capillus-veneris mRNA. clone: YMU02A01NGRL0013_G11. 5' end seq ... + G P+ TY+ + AC+ E Sbjct: 97 YSFNYMIRGLTNTWN-------DHEA ---ALSLYRRMKFSGLKPDKFTYNFVFIACAKLE 146 Query: 214 A ... Sbjct: 71 LIPKAVELGDFNYSSFLFSVTEEPNHYSFNYMIRGLTNTWNDHEA ALSLYRRMKFSGLKP 130 Query: 469 DGATFSCVLRACGNVGALDV ...

  16. AcEST: DK949372 [AcEST

    Full Text Available TST38A01NGRL0005_N02 627 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0005_N02. 5' end seq ... 363 DQLREKTC-GVDKFDDIVMACXXXXXXXXXXXXXXXXXXKARVHAYGVCD DPEYFYDYVQ 539 Q++EK G+ FDDIV+AC KA+VHA+ VCD DP+YFYD ... 264 QQVQEKKVPGITFFDDIVVACGSGGSIAGLSLGSYLSNLKAKVHAFAVCD DPDYFYDYTQ 323 Query: 540 GLLDGMNANIASRDIVNVIDAKGLG ...

  17. Energy saving in ac generators

    Nola, F. J.

    1980-01-01

    Circuit cuts no-load losses, without sacrificing full-load power. Phase-contro circuit includes gate-controlled semiconductor switch that cuts off applied voltage for most of ac cycle if generator idling. Switch "on" time increases when generator is in operation.

  18. Apuntes de Acústica

    Martín Domingo, Agustín

    2014-01-01

    Esta publicacion contiene unos apuntes para la parte de Acústica de las asignaturas de la ETSAM, junto con cierta cantidad de material adicional que excede el ámbito del curso. Aunque está lejos de ser completa y de estar libre de errores, el autor espera sea útil.

  19. SSTI Clark ACS Technology Demonstrations

    Freesland, Douglas

    1997-01-01

    SSTI Clark, one of two spacecraft built under NASA's Small Satellite Technology Initiative, includes seven ACS technology demonstrations. The technologies redefine the performance cost envelope, providing improved sensor and actuator performance at reduced costs. Six sensing technologies are being flown consisting of both hardware and algorithmic demonstrations: autonomous star tracker, hemispherical resonating gyro, GPS attitude determination, miniature horizon sensors, low cost course sun s...

  20. AcEST: DK950895 [AcEST

    Full Text Available |A7SFA3|A7SFA3_NEMVE Predicted protein OS=Nematostella vectens... 210 5e-53 tr|Q0CVA9|Q0CVA9_ASPTN ATP-citrate synthase subunit...stX Result : Swiss-Prot sp_hit_id Q54YA0 Definition sp|Q54YA0|ACLY_DICDI Probable ATP-citrate synthase OS=Dictyos...PIDYSWAQELGLIRKPAAFISTI 404 >sp|Q8X097|ACL1_NEUCR Probable ATP-citrate synthase subunit 1 OS=Neurospora cras...IRKPASFMTSI 844 >sp|Q9P7W3|ACL1_SCHPO Probable ATP-citrate synthase subunit 1 OS=Schizosaccharomyces pombe G....done Score E Sequences producing significant alignments: (bits) Value sp|Q54YA0|ACLY_DICDI Probable ATP-citrate synthase OS=Dictyos

  1. AcEST: BP914304 [AcEST

    Full Text Available IDEHTFVFTLRAC 4 V+ NA++ Y G+ E A++ + +M+ E++ + TF+ LRAC Sbjct: 670 VTWNAMICGYAHHGKGEEAIQLFERMILENIKPNHVTFISI...KSLRRDFVTWNAMICGYAHHGKGEEAIQLFERMILENIKPN 703 Query: 339 NLTYVSLFKACGNVLDFGQG-RTIHGEARANGFSSDRFICTTLI...TFVFTLRAC 4 +F + + V+ N ++ +YV A +++M + D TL+AC Sbjct: 484 QIFERMCDRDNVTWNTIIGSYVQDENESEAFDLFKRMNLCGIVSDGACL...K + A+Q+ + R + +W++MI++ +A + ++ M Sbjct: 93 LGNSLINFYSKFEDVASAEQVFRRMTLRDVVTWSSMIAAYAGNNHPAKAFDTFERMTDAN 152... + R + +W++MI++ +A + ++ M Sbjct: 93 LGNSLINFYSKFEDVASAEQVFRRMTLRDVVTWSSMIAAYAGNNHPAKAFDTFERM

  2. AcEST: BP911793 [AcEST

    Full Text Available + +VSWN +++ Y QHG + ++L+ M+AE T N + + A Sbjct: 58 EAKFVFERIQNKDVVSWNCIINGYSQHGPSGSSHVMELFQRMRAENTAPNAHTFAGVF... N + + A Sbjct: 58 EAKFVFERIQNKDVVSWNCIINGYSQHGPSGSSHVMELFQRMRAENTAPNAHTFAGVFTA 117 Query: 359 CIQTGNLELCKQM...D VT S+LSACSH G + +G YF Sbjct: 602 IIGGSAQHGRGQDALQLFERMKMEGVKPDIVTFVSLLSACSHAGLLEEGRRYF 654 Score = 115 bit...53 QTGNLELCKQMHFNIVSAGNELNPSLASSLIRTYGNCGSMLDAHAVFDSLPLPDIVSWNV 174 Q +E+ K++ F+++ N S +++I Y CG + +A +FD +P D VSW Sbjct: 324 QGERME... L+ M +E + I+LV +L AC+ TG+LE + +H Sbjct: 498 VITWNAMIASYVHCEQSEKAIALFDRMVSENFKPSSITLVTLLMACVNTGSLER

  3. AcEST: BP921649 [AcEST

    Full Text Available 40 + ++LV YAK L + ++ +P R W+ +I+ + + ++E AL+ + M+ G Sbjct: 144 VASSLVGMYAKFNLFENSLQVFDEMPERDVASWNTVISCFYQSGEAEKALELFGRME...LDCYKEM 52 ++L +GNALVD YAKCG L A ++ +R+ R V W+ +I Y + E A D +K M Sbjct: 461 KNLFVGNALVDMYAKCGALEDARQIFERMCDRDNVTWNTIIGSYVQDEN...RD+ WNA+I Sbjct: 237 LEQGKQIHCYAIRSG-IESDVLVVNGLVNMYAKCGNVNTAHKLFERMPIRDVASWNAIIG 295 Query: 411 GYVNHGRAEVALDCFGKME...SNDVV-GNALVNMYAKCGNVNSAYKLFERMPKKNVVAWNAIIS 396 Query: 411 GYVNHGRAEVALDCFGKME... HGR + AL F +M+ EG PD +TF +L AC G + + + + Sbjct: 603 IGGSAQHGRGQDALQLFERMKMEGVKPDIVTFVSLLSACSHAGLLEEGRRYFCSM

  4. AcEST: BP919669 [AcEST

    Full Text Available D + RDV SW ++S + + G+ ++F M G +P+ Sbjct: 148 LVGMYAKFNLFENSLQVFDEMPERDVASWNTVISCFYQSGEAEKALELFGRMESSGFEPN 20...+ +++AC L + +G+E+H + K+G EL V Sbjct: 190 EKALELFGRMESSGFEPNSVSLTVAISACSRLLWLERGKE...F Sbjct: 468 IY---VVNSLIDSYGKCSHVEDAERIFEECTIGDLVSFTSMITAYAQYGQGEEALKLFLE 524 Query: 226 MVGEGTKPDSISLLVVLRA-YNF...+ IR DV W +LMSGY+K D ++F ++ Sbjct: 44 SLINVYFTCKDHCSARHVFENFDIRSDVYIWNSLMSGYSKNSMFHDTLEVFKRLLNCSIC 103 Query: 208 KPDSISLLVVLRAYNF...KPD Sbjct: 261 VDMYAKCGCIETAVEVFEKLTRRNVFSWAALIGGYAAYGYAKKATTCLDRIEREDGIKPD 320 Query: 199 SISLLVVLRAYNFLGFP

  5. AcEST: DK957916 [AcEST

    Full Text Available PQKQPVPAVSHSPQKSSTPPTPAATKPKEEPSVPKEVPKLQQGKLEKT 967 Query: 577 --TTEASQGIPVEEG...G E+ P+ P Sbjct: 1974 QEQGRAPSQDQEAPSPEALPSPGQEPAAGASPRRGELRRGSSAESALPRAGP 2025 >sp|Q05175|BASP_RAT Brain ac... +P AP P Sbjct: 388 ERETAASAGPQG----AFPEPRPAQPSAGPEPRPAQPSAGPEPRPAQPSAAPEPRP---- 439 Query: 571 GQTTE... L ++ +A+ +E AP Sbjct: 406 IVTTPEPEGSGEEDVPKPDEIPEKEVTEEELIKVSTAAPAKASPEEEVVKATTLAPSEED 465 Query: 550 VSPYIASGQTTE... Query: 424 KGQAYEAIPDPHVDPAAGVHERLAQLQLGDEPEATKPKEAPG-VSPYI--ASGQTTEASQ 594 K A E P + + G E + E EA P A G +P

  6. AcEST: DK956923 [AcEST

    Full Text Available CCATAGTCTCAA CAGCGATAAGCAGGAAATGCATGCAGTGACCATGGGTAAGAAAAGGGTCATGGTGGGCGC CATTAACACGATACTTATCCTA...CTCCTCTTGCAGTTTATGAAGCAATGTTCTTCCTCTTC TAGTCATGATGATGATGGCGATGCCTTTGCGGATGACACTCTAAGCAGACGCAACGAT...AC GGTCGAGTCTGCTCCTCGACATTGGCCAAGGCGAATGCTGGGCAGCCAAGAACCTGCCTC CAACAAGACTTCATATGGTATTCCTGAT...H At1g73965 (CLE13 / CLAVATA3/ESR-Related 13) (CLE13) OS=Arabidopsis thaliana Align length 25 Sco...icant alignments: (bits) Value tr|Q6NMF0|Q6NMF0_ARATH At1g73965 (CLE13 / CLAVATA3/ESR-Related 1... 49 3e-04

  7. AcEST: BP921492 [AcEST

    Full Text Available + AL +G+ +H Sbjct: 286 DVASWNAIIGGYSLNSQHHEALAFFNRMQVRGIKPNSITMVSVLPACAHLFAL... ++ L +GK +H Sbjct: 178 NLVSWTAMVSGYAQGGFADEALRMFYEMQGEDVKANYVTVASVLPACAQLSDLQQGKEIH 237 Query: 153 AC...FDRMPEK 171 Query: 333 DVVSWSAMIAMYGQQGCGKEAFQLFQEMACEGGMPNRVTYVSILDACASVAALPEGKLVH 154 +V+W+++++ + Q G EA Q+F +M G P+ T+VS+L ACA...333 DVVSWSAMIAMYGQQGCGKEAFQLFQEMACE-GGMPNRVTYVSILDACASVAALPEGKLV 157 +V +W+AMI+ YG G G++A +LF +M + G +PN VT+V++L ACA...SKL 85 Query: 288 GCGKEAFQLFQEMACEGGMPNRVTYVSILDACASVAALPEGKLVHACFMESELELDVVVG 109 ++ M P+ T+ S++ +CA ++AL G

  8. Performance of AC/graphite capacitors at high weight ratios of AC/graphite

    Wang, Hongyu [IM and T Ltd., Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki [Advanced Research Center, Department of Applied Chemistry, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2008-03-01

    The effect of negative to positive electrode materials' weight ratio on the electrochemical performance of both activated carbon (AC)/AC and AC/graphite capacitors has been investigated, especially in the terms of capacity and cycle-ability. The limited capacity charge mode has been proposed to improve the cycle performance of AC/graphite capacitors at high weight ratios of AC/graphite. (author)

  9. Simultaneous distribution of AC and DC power

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  10. AcEST: DK948526 [AcEST

    Full Text Available TST38A01NGRL0003_I19 675 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0003_I19. 5' end seq ... IAMVRTTTPVYV 214 Query: 542 ALALFNQARVSSLPIIDDNGSLIDIY ARSDITALARDDTY 661 AL +F Q RVS+LP++D+ G ++DIY ++ D+ ... LA + TY Sbjct: 215 ALGIFVQHRVSALPVVDEKGRVVDIY SKFDVINLAAEKTY 254 >sp|Q09138|AAKG1_PIG 5'-AMP-acti ... IAMVRTTTPVYV 215 Query: 542 ALALFNQARVSSLPIIDDNGSLIDIY ARSDITALARDDTY 661 AL +F Q RVS+LP++D+ G ++DIY ++ D+ ... LA + TY Sbjct: 216 ALGIFVQHRVSALPVVDEKGRVVDIY SKFDVINLAAEKTY 255 >sp|O54950|AAKG1_MOUSE 5'-AMP-ac ...

  11. AcEST: DK962916 [AcEST

    Full Text Available TST39A01NGRL0015_C06 596 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0015_C06. 5' end seq ... NA. clone: TST39A01NGRL0015_C06. 5' end sequence. Acce ssion DK962916 Tissue type prothallia with plantlet ... 2 Query: 317 MPKSKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 442 MP+ K+PC ++AC+IQ CL NN++ +C VI+ L+ CC + Sbjct ... me = +2 Query: 335 PCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 442 PC +EAC IQ CL+ + + +C VI+ L CC K Sbjct: 4 PCQ ... = +2 Query: 326 SKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE KCNSK 454 + E C+ CD +TC +K F +C AL CCE KC K Sbjct: 4 ...

  12. AcEST: DK955705 [AcEST

    Full Text Available TST39A01NGRL0023_N02 635 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0023_N02. 5' end seq ... NA. clone: TST39A01NGRL0023_N02. 5' end sequence. Acce ssion DK955705 Tissue type prothallia with plantlet ... 2 Query: 296 MPKSKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 421 MP+ K+PC ++AC+IQ CL NN++ +C VI+ L+ CC + Sbjct ... me = +2 Query: 314 PCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 421 PC +EAC IQ CL+ + + +C VI+ L CC K Sbjct: 4 PCQ ... = +2 Query: 305 SKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE KCNSK 433 + E C+ CD +TC +K F +C AL CCE KC K Sbjct: 4 ...

  13. AcEST: DK961330 [AcEST

    Full Text Available FWVPCMHTPIKQEKHTHA 405 +AR P W +++PI+ ++C++ P + AK+ PL DVTH+F+V + +QE Sbjct: 61 VARRTRP-SWHEDNPINYVQCDISDPDD...+IL +D PGGPWKVYG Sbjct: 4 WWAGAIGAAKKKLEEDDAPPKHS---SVALIVGVTGIIGNSLAEILPLADTPGGP...AWHEDNPINYIQCDISDPDDSLAKLSPLTDVTHVFYVTCANR--STEPENCE 117 Query: 406 MATHMFENIIGVLLTHAPNLQHVCMQTSDKHY-... : Swiss-Prot sp_hit_id Q7MXT7 Definition sp|Q7MXT7|LPXD_PORGI UDP-3-O-[3-hydroxymyristoyl] glucosamine N-ac...lue sp|Q7MXT7|LPXD_PORGI UDP-3-O-[3-hydroxymyristoyl] glucosamine N-... 34 0.62 sp|P60369|KR103_HUMAN Kerati

  14. AcEST: BP913772 [AcEST

    Full Text Available N VT V L C+ G G+ H Sbjct: 350 NVVTWSAVIAGYAQRGLGFEALDVFRQMRLCGSEPNVVTLVSLLSGCALAGTLLHGKETH 409 Query: 376 IEIER--RGLLEVDP-...VFNKLSVQDIVSW 236 + + A ++G+++H I RRGL + PV+ + LV MY R G L Q VF+++ +D+VSW Sbjct: 296 ASLAALEQGKLIHGYILRRGLDSILPVI-S... TF M+ +PN+VT V VL+AC+ + Q + Sbjct: 250 SWSAMIACYAKNGKAFEALRTFREMMRETKDSSPNSVTMVSVLQACASLA...MIEGGVAPNAVTFVVVLRACSQTGSYSQSQTFFEAMSKNF 50 + G A G + F+ M + GV PNAVTFV VLR CS G + Q F++M F Sbjct: 312 ALNGLAMNGFGEKCLELFSL...L YA G + + +F++ D+ +TA + + Sbjct: 48 IHAAILRHNLLLHPRYPVLNLKLHRAYASHGKIRHSLALFHQTIDP

  15. AcEST: DK952954 [AcEST

    Full Text Available TST38A01NGRL0015_H21 616 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0015_H21. 5' end seq ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS ... 541 ++ Q K +HA I + D + V + L+++Y+KCGSI DA F +++T+ ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS GS 547 + + IHA S D ++ LV LYS+CG IE+++ F + ++ W+ ++S ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS ... 541 DL + IH+ I+ + ++ +V S L+++Y+K G ++ A ++ + A + ... EA+ LF +M G+ P + + L AC Sbjct: 243 RVFDGLRLKDHSSWVAMIS GLSKNECEAEAIRLFCDMYVLGIMPTPYAFSSVLSACKKIE 302 Query ...

  16. AcEST: BP912540 [AcEST

    Full Text Available YMU001_000020_B03 501 Adiantum capillus-veneris mRNA. clone: YMU001_000020_B03. BP912540 - Show ... 2 EELTVHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAV 181 EE VH TAS+GDVE LKA LA G +KDE+DSEGRTAL ... ry: 14 VHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAVDAVD 193 +H A V ++ LL GAD KD G LH AC YG AE ... uery: 26 ASVGDVEALKALLAEGADKDEKDSEGR--TALHFACGYGEVMCAE VLLEAGVAVDAVDKN 199 + GD+E +K L + + + +D EGR T LHFA ... ry: 14 VHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAVDAVD 193 +H A ++E + LL GAD + +D G LH A YG ...

  17. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Rakan Kh Antar

    2013-01-01

       This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time fo...

  18. Universality of ac conduction in disordered solids

    Dyre, Jeppe; Schrøder, Thomas

    2000-01-01

    non-power-law universalities. It is argued that ac universality reflects an underlying percolation determining dc as well as ac conductivity in the extreme disorder limit. Three analytical approximations to the universal ac conductivities are presented and compared to computer simulations. Finally......The striking similarity of ac conduction in quite different disordered solids is discussed in terms of experimental results, modeling, and computer simulations. After giving an overview of experiment, a macroscopic and a microscopic model are reviewed. For both models the normalized ac conductivity...... as a function of a suitably scaled frequency becomes independent of details of the disorder in the extreme disorder limit, i.e., when the local randomly varying mobilities cover many orders of magnitude. The two universal ac conductivities are similar, but not identical; both are examples of unusual...

  19. Short term dynamic aperture with AC dipoles

    Mönig, Saskia; Persson, Tobias Hakan Bjorn; Coello De Portugal, Jaime; Langner, Andy; Tomas, Rogelio; CERN. Geneva. ATS Department

    2015-01-01

    The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. The effect of the AC dipole on the dynamic aperture is studied within this note.

  20. ac electroosmosis in rectangular microchannels.

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects. PMID:16351310

  1. DESARROLLO RURAL A.C.

    Alfredo Aguilar Valdés

    2015-01-01

    Full Text Available El objetivo de este trabajo fue analizar el diagnostico situacional de una Empresa de Servicios Profesionales en el caso de: Instituto de Promoción Para el Desarrollo Rural A.C., a través de la Metodología “UALAE” así como la oportunidad que como empresa presenta. Este estudio se realizó en el municipio de Saltillo, Coahuila, México. Adoptó esta Metodología UALAE y se difundió su opinión. El Instituto de Promoción Para el Desarrollo Rural A.C., está formado por profesionistas y productores cuya finalidad es la de contribuir al desarrollo del medio rural con proyectos de viabilidad técnica, económica y social, sobre la base de necesidades reales y al aprovechamiento sustentable del potencial de los recursos naturales. Su buen funcionamiento es indispensable e importante para el desarrollo de los productores agropecuarios principalmente, debido a que se ven muy beneficiados con todos los servicios que se les brinda, se han logrado buenos proyectos, buenas capacitaciones y un gran crecimiento de sus productos. Mediante el proceso de asistencia técnica a organizaciones de productores, se induce la formulación adecuada de proyectos viables desde el punto visto del mercado, la rentabilidad económica, las tecnologías disponibles y de la organización social.

  2. AcEST: BP920845 [AcEST

    Full Text Available 45|Adiantum capillus-veneris mRNA, clone: YMU001_000142_D08. (514 letters) Database: uniprot_sprot.fasta 412,525 seq...P7 OS=Magnapor... 33 1.0 sp|Q7VF68|SYH_HELHP Histidyl-tRNA synthetase OS=Helicobacter hep... 31 3.8 sp|P1305...90 FTGFLVLHSEPRQQPQVDL 1608 >sp|A4QX49|DBP7_MAGGR ATP-dependent RNA helicase DBP7 OS=Magnaporthe grise...T PT VT+H + T+ AC+ A+TT+ H H Sbjct: 481 PPKETKPTK------PVTNHTESTVGKACYITSAANTTITLHKLH 519 >sp|Q7VF68|SYH_HELHP His...rot_trembl.fasta 7,341,751 sequences; 2,391,615,440 total letters Searching.................................

  3. AcEST: DK960083 [AcEST

    Full Text Available ome P450 71D7 OS=Solanum chacoense ... 96 1e-19 sp|Q9SAB6|C71AI_ARATH Cytochrome ...... 96 2e-19 sp|P93530|C71D6_SOLCH Cytochrome P450 71D6 OS=Solanum chacoense ... 94 5e-19 sp|Q9T0K2|C71AK_AR... paten... 176 1e-42 tr|Q9AXP9|Q9AXP9_POPJC Cinnamate 4-hydroxylase OS=Populus jackii... 176 2e-42 tr|Q40907|Q40907_POPKI Cinnamic ac...8 KVVQQSRGAWEDEALRVIQDLKA 160 >tr|Q9AXP9|Q9AXP9_POPJC Cinnamate 4-hydroxylase OS=Populus jackii GN=C4H PE=2 ...e-42 tr|A9PBZ7|A9PBZ7_POPTR Putative uncharacterized protein OS=Popul... 176 2e-4

  4. AcEST: DK955376 [AcEST

    Full Text Available TST39A01NGRL0022_O23 611 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0022_O23. 5' end seq ... LMDETRAAGIKL 210 Query: 602 AIC 610 A+C Sbjct: 211 AVC ... 213 >tr|A9SM81|A9SM81_PHYPA Predicted protein OS=P ... C 610 VLELMD A+ KGLKVA+C Sbjct: 196 VLELMDAAREKGLKVAVC ... 213 >tr|Q8L7U1|Q8L7U1_ARATH AT4g39970/T5J17_140 OS ... LKVAIC 610 LMDEA+A G K+A+C Sbjct: 182 RLMDEAKAAGKKLAVC ... 197 >tr|Q680K2|Q680K2_ARATH MRNA, complete cds, cl ... LKVAIC 610 LMDEA+A G K+A+C Sbjct: 182 RLMDEAKAAGKKLAVC ... 197 >tr|Q8LAS1|Q8LAS1_ARATH Putative uncharacteriz ...

  5. AcEST: BP913416 [AcEST

    Full Text Available GCATGTAGTTTGGA CAGAGATG ■■Homology search results ■■ - Swiss-Prot (release 56.9) Link to BlastX Result : Swi...AC_BACFN Uronate isomerase OS=Bacteroides fragilis (... 30 4.5 sp|Q3ITT7|SYA_NATPD Alanyl-tRNA synthetase OS=Natronomonas phar...C++ N IP+ M C Sbjct: 417 LSYPRHEYFRRTLCNLLGCDVENGEIPLSEMERVC 451 >sp|Q3ITT7|SYA_NATPD Alanyl-tRNA synthetase OS=Natronomonas phar...ng, Webb Miller, and David J. Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database searc...148,809,765 total letters Searching..................................................done Score E Sequences

  6. AcEST: DK947388 [AcEST

    Full Text Available Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database search programs, Nucleic Ac...ids Res. 25:3389-3402. Query= DK947388|Adiantum capillus-veneris mRNA, clone: YMU02A01NGRL0015_L18, 5' (587 letters) Databa... generation of protein database search programs, Nucleic Acids Res. 25:3389-3402. Query= DK947388|Adiantum c...apillus-veneris mRNA, clone: YMU02A01NGRL0015_L18, 5' (587 letters) Database: uniprot_trembl.fasta...-ribosylation factor 1 OS=Salix bakko GN... 268 1e-71 sp|P49076|ARF_MAIZE ADP-ribosylation factor OS=Zea may

  7. AcEST: BP916217 [AcEST

    Full Text Available inase kinase 7-interacting protein 3 OS=Mus musculus Align length 119 Score (bit) 35.0 E-value 0.16 Report B...visiae GN... 30 6.8 >sp|Q571K4|TAB3_MOUSE Mitogen-activated protein kinase kinase kinase 7-interacting protein 3 OS=Mus musculus...protein kinase kinase kinase 7 interacting protein 3 OS=Mus musculus GN=Map3k7ip3 PE=2 SV=1 Length = 716 Sco...(3)malignant brain tumor-like 2 prot... 31 2.3 sp|P33234|ADIY_ECOLI HTH-type transcriptional regulator adiY ...ZZC3_PSEU2 Membrane protein, putative OS=Pseudomonas... 35 2.5 tr|Q5U7D5|Q5U7D5_9BACI OpuAC OS=Halobacillus trueperi GN=opu

  8. AcEST: DK953324 [AcEST

    Full Text Available |LSRR_PHOLL Transcriptional regulator lsrR OS=Photorhab... 30 6.1 sp|A0JY64|ATPB_ARTS2 ATP synthase subunit beta OS=Arthroba...cter s... 30 6.1 sp|A1R7V3|ATPB_ARTAT ATP synthase subunit beta OS=Arthroba...ATP synthase subunit beta OS=Arthrobacter sp. (strain FB24) GN=atpD PE=3 SV=1 Len...KD 372 Query: 311 HLHFTHRGKQRL 346 H + R KQ L Sbjct: 373 HYNTAVRVKQIL 384 >sp|A1R7V3|ATPB_ARTAT ATP synthase subunit beta OS=Arthroba...T and PSI-BLAST: a new generation of protein database search programs, Nucleic Ac

  9. AcEST: DK945049 [AcEST

    Full Text Available R 148 >sp|Q9X5X3|ATCU_SINMW Copper-transporting P-type ATPase OS=Sinorhizobium medicae (strain WSM419) GN=ac...|Q4EPP8|Q4EPP8_LISMO Heavy metal-binding protein OS=Listeria m... 34 3.2 tr|A6AST1|A6AST1_VIBHA Copper-trans..... 31 2.7 sp|Q4X0S7|DPH1_ASPFU Diphthamide biosynthesis protein 1 OS=Asper... 30 4.5 sp|A2VDJ0|T131L_HUMAN Transmembran...P58342|ATCU2_RHIME Copper-transporting ATPase 2 OS=Rhizobium meliloti Align length 75 Score (bit) 34.7 E-val...sophila ... 30 7.8 >sp|P58342|ATCU2_RHIME Copper-transporting ATPase 2 OS=Rhizobium me

  10. SINGLE PHASE HIGH FREQUENCY AC CONVERTER FOR INDUCTION HEATING APPLICATION

    M.A INAYATHULLAAH,; Dr. R. Anita

    2010-01-01

    The proposed topology reduces the total harmonic distortion (THD) of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with ...

  11. Characterization of AcMNPV with a deletion of ac69 gene

    Jianhao Ke

    2011-07-01

    Full Text Available ORF69 (Ac69 of Autographa californica multiple nucleopolyhedrovirus (AcMNPV is conserved in some baculovirus genomes. Although it has been shown that Ac69 has cap 0-dependent methyltransferase activity and is not required for budded virus production in Spodoptera frugiperda Sf-9 cells, its role in occlusion-derived virus synthesis and virus oral infectivity is not known. This paper describes generation of an ac69 knockout AcMNPV bacmid mutant and analyses of the influence of ac69 deletion on the viral infectivity in Sf-9 cells and Trichoplusia ni larvae so as to investigate the role of ac69 in the viral life cycle. Results indicated that ac69 deletion has little effect on the production rates and morphogenesis of budded virus and occlusion-derived virus in Sf-9 cells. In addition, animal experiment revealed that the deletion mutant did not affect AcMNPV infectivity for Trichoplusia ni larvae in LD50 and LT50 bioassay when administered orally. These results suggest that ac69 may be dispensable for viral infectivity both in vitro and in vivo.

  12. Noise reduction in AC-coupled amplifiers

    Serrano Finetti, Roberto Ernesto; Pallàs Areny, Ramon

    2014-01-01

    AC-coupled amplifiers are noisier than dc-coupled amplifiers because of the thermal noise of the resistor(s) in the ac-coupling network and the increased contribution of the amplifier input noise current i(n). Both contributions, however, diminish if the corner frequency f(c) of the high-pass filter observed by the signal is lowered, the cost being a longer transient response. At the same time, the presence of large resistors in the ac-coupling network suggests that the use of FET-input ampli...

  13. The Effect of the Feedback Controller on Superconducting Tokamak AC Losses + AC-CRPP user manual

    Superconducting coils in a Tokamak are subject to AC losses when the field transverse to the coil current varies. A simple model to evaluate the AC losses has been derived and benchmarked against a complete model used in the ITER design procedure. The influence of the feedback control strategy on the AC losses is examined using this model. An improved controller is proposed, based on this study. (author)

  14. Guiding Principles in Selecting AC To DC Converters For Power Factor Corrections in AC Transmission System

    Ibekwe B.E

    2014-10-01

    Full Text Available The ac to dc converters’ power factors correction in ac transmission system were investigated. The studies include: phase-controlled converter; pulse width modulated (PWM converter and ac input current shaped converter. Using Fourier series, power factors of these converters were calculated and simulated using MATLAB. The resulting curves are displayed in the hard copies for practical guides in the choice of converters; and comparatively, current shaped type is the best.

  15. A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System

    Marian GAICEANU; Emil ROSU

    2003-01-01

    In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM) is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller) 30 MIPS 32-bit fixed-point digital signal processor (DSP), were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation ...

  16. Transport AC losses in YBCO coated conductors

    Majoros, M [Ohio State University, Columbus, OH 43210 (United States); Ye, L [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Velichko, A V [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Coombs, T A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Sumption, M D [Ohio State University, Columbus, OH 43210 (United States); Collings, E W [Ohio State University, Columbus, OH 43210 (United States)

    2007-09-15

    Transport AC loss measurements have been made on YBCO-coated conductors prepared on two different substrate templates-RABiTS (rolling-assisted biaxially textured substrate) and IBAD (ion-beam-assisted deposition). RABiTS samples show higher losses compared with the theoretical values obtained from the critical state model, with constant critical current density, at currents lower than the critical current. An origin of this extra AC loss was demonstrated experimentally by comparison of the AC loss of two samples with different I-V curves. Despite a difference in I-V curves and in the critical currents, their measured losses, as well as the normalized losses, were practically the same. However, the functional dependence of the losses was affected by the ferromagnetic substrate. An influence of the presence of a ferromagnetic substrate on transport AC losses in YBCO film was calculated numerically by the finite element method. The presence of a ferromagnetic substrate increases transport AC losses in YBCO films depending on its relative magnetic permeability. The two loss contributions-transport AC loss in YBCO films and ferromagnetic loss in the substrate-cannot be considered as mutually independent.

  17. The Sloan Lens ACS Survey. V. The full ACS strong-lens sample

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Gavazzi, Raphael; Moustakas, Leonidas A.; Wayth, Randall; Schlegel, David J.

    2008-01-01

    We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift c

  18. AC losses in filamentary YBCO/hastelloy

    Full text: The AC hysteresis loss of a long YBCO thin-film superconducting strip in a perpendicular AC magnetic field can be reduced by subdividing the film into narrow parallel strips (filaments). The hysteresis loss depends on the film critical current density Jc, the film thickness d, the filament width 2a and the lateral spacing L between filaments as well as on the AC magnetic field amplitude Hm. In addition, if the film is deposited onto a YSZ/hastelloy substrate to form a flexible tape, eddy current loss occurs in the hastelloy metal. The eddy current loss depends on the resistivity p of the hastelloy, the width 2w and thickness dm of the hastelloy substrate as well as on the frequency f and amplitude Hm. We have calculated the hysteresis and eddy current losses as a function of Jc, d, 2a, L, p, w, dm, f, and Hm to find optimal design parameters for a YBCO/hastelloy tape. As the AC loss is related to the loss component X'' of the AC susceptibility, we have measured X'' at different frequencies f and amplitudes Hm for several filamentary designs of YBCO/hastelloy tapes and compared our experimental results with our model calculations

  19. AC loss performance of CS insert coil

    The ITER Central Solenoid (CS) model coil and the CS insert coil were fabricated, and the test was carried out. The AC loss measurement of the coil is one of the most important tests to determine coil performance. The AC loss of a short sample conductor for the CS insert coil was measured by using the calorimetric method, and the coupling time constants of the conductor were estimated to be 30 ms and 20 ms for pulse and discharge tests, respectively. The AC loss of the CS insert coil was measured by using the calorimetric method for pulse and discharge tests. The coupling time constant estimated from the result of the pulse tests was 34 ms and almost equal to that of the short sample. The coupling time constant for the discharge test was estimated to be 140 ms and about 4 times that of the pulse test. (author)

  20. ac propulsion system for an electric vehicle

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  1. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  2. ACS air bearing test-bed design

    Glitt, Sascha

    2010-01-01

    This thesis is about the construction and design of a new air bearing test-bed to verify the programmed ACS attitude control algorithm and to validate the ACS MATLAB/SimuLink¬ model of NPSAT1, the second small satellite currently under development at the Naval Postgraduate School Space Systems Academic Group. The software was already verified and validated using a comparable air bearing test-bed. But due to changes in hardware from commercial magnetic torque rods to custom, NPS-built, magneti...

  3. The Effective AC Response of Nonlinear Composites

    WEI En-Bo; GU Guo-Qing

    2001-01-01

    A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form J = σ E + χ|E|2 E with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media vith a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility χ*3ω at the third harmonic frequency.

  4. YBCO thin films in ac and dc films

    Shahzada, S

    2001-01-01

    We report studies on the dc magnetization of YBCO thin films in simultaneously applied dc and ac fields. The effect of the ac fields is to decrease the irreversible magnetization drastically leading to complete collapse of the hysteresis loops for relatively small ac fields (250e). The magnitude of the decrease depends on the component of the ac field parallel to the c-axis. The decrease is non-linear with ac amplitude and is explained in the framework of the critical state response of ultra thin films in perpendicular geometry. The ac fields increase the relaxation rapidly at short times while the long time response appears unaffected. (author)

  5. SINGLE PHASE HIGH FREQUENCY AC CONVERTER FOR INDUCTION HEATING APPLICATION

    M.A INAYATHULLAAH,

    2010-12-01

    Full Text Available The proposed topology reduces the total harmonic distortion (THD of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with extremely low distortion.. This power converter is more suitable and acceptable for cost effective high frequency (HF consumer induction heating applications.

  6. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx. PMID:26672449

  7. AC power generation from microbial fuel cells

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  8. Performance of Halbach magnetized brushless AC motors

    Zhu, Z.Q.; Xia, Z.P.; Shi, Y.F.; Howe, D.; Pride, A.; X. J. Chen

    2003-01-01

    The steady-state performance of Halbach magnetized brushless ac machines when operated in constant torque and flux-weakening modes is investigated both theoretically and experimentally, with particular emphasis on the influence of cross-coupling magnetic saturation on the torque capability.

  9. Ac-dc converter firing error detection

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal

  10. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    2000-01-01

    The present study discusses the AC loss in high-temperature superconductors. Superconducting materials with a relatively high critical temperature were discovered in 1986. They are presently developed for use in large-scale power-engineering devices such as power-transmission cables, transformers an

  11. Digital model for harmonic interactions in AC/DC/AC systems

    Guarini, A.P.; Rangel, R.D.; Pilotto, L.A.S.; Pinto, R.J.; Passos Junior, R. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The main purpose of this paper is to present a model for calculation of HVdc converter harmonics taking into account the influence of the harmonic interactions between the ac systems in dc link transmissions. The ideas and methodologies used in the model development take into account the dc current ripple and ac voltage distortion in the ac systems. The theory of switching functions is applied to contemplate for the frequency conversions between the ac and dc sides, in an iterative process. It is possible then to obtain, even in balanced situations, non-characteristic harmonics that are produced by frequencies originated in the other terminal, which can be significant in a strongly coupled system, such as back-to-back configuration. (author) 9 refs., 3 figs.

  12. A Comparison Between Two Average Modelling Techniques of AC-AC Power Converters

    Pawel Szczesniak

    2015-03-01

    Full Text Available In this paper, a comparative evaluation of two modelling tools for switching AC-AC power converters is presented. Both of them are based on average modelling techniques. The first approach is based on the circuit averaging technique and consists in the topological manipulations, applied to a converters states. The second approach makes use of state-space averaged model of the converter and is based on analytical manipulations using the different state representations of a converter. The two modelling techniques are applied to a same AC-AC converter called matrix-reactance frequency converter based on buck-boost topology. These techniques are compared on the basis of their rapidity, quantity of calculations and transformations and its limitations.

  13. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  14. Rapid cycling synchrotron magnet with separate ac and dc circuit

    In present rapid cycling synchrotron magnets ac and dc currents flow in the same coil to give the desired field. The circuit reactance is made zero at dc and the operating frequency by running the magnet in series with an external parallel resonant LC current. We propose to return the ac flux in a gap next to the synchrotron. The dc coil encloses the ac magnetic circuit and thus links no ac flux. A shorted turn between the dc coil and ac flux enhances the separation of the two circuits. Several interesting developments are possible. The dc coil could be a stable superconductor to save power. The ac flux return gap could be identical with the synchrotron gap and contain a second synchrotron. This would double the output of the system. If the return flux gap were used for a booster, the ac coil power could be greatly reduced or radiation hardening of the ac coil could be simplified

  15. Design of Three Phase Matrix Converter AC-AC Utility Power Supply using SPWM Technique

    Sagar.S.Pawar; Prakash.T.Patil

    2015-01-01

    This paper describes the control analysis and design of an three phase matrix AC-AC utility power supply .The SPWM modulation techniques is used to control the desired output voltage and gives the control output voltage and reduced input harmonic distortions .In this Matrix converter Input is directly connected to output no DC link components is required. Simulation had been done using mat lab simulink and Simulated results are observed

  16. Design of Three Phase Matrix Converter AC-AC Utility Power Supply using SPWM Technique

    Sagar. S. Pawar

    2015-04-01

    Full Text Available This paper describes the control analysis and design of an three phase matrix AC-AC utility power supply .The SPWM modulation techniques is used to control the desired output voltage and gives the control output voltage and reduced input harmonic distortions .In this Matrix converter Input is directly connected to output no DC link components is required. Simulation had been done using mat lab simulink and Simulated results are observed

  17. A Comparison Between Two Average Modelling Techniques of AC-AC Power Converters

    Pawel Szczesniak

    2015-01-01

    In this paper, a comparative evaluation of two modelling tools for switching AC-AC power converters is presented. Both of them are based on average modelling techniques. The first approach is based on the circuit averaging technique and consists in the topological manipulations, applied to a converters states. The second approach makes use of state-space averaged model of the converter and is based on analytical manipulations using the different state representations of a converter. The two m...

  18. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

  19. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    S. Arumugam S. Ramareddy M. Sridhar

    2011-01-01

    This paper presents a novel soft-switching pulse width modulation (PWM) utility frequency AC to high frequency (HF) AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which ...

  20. Adaptive Nonlinear Control of Induction Motors through AC/DC/AC Converters

    Elfadili, Abderrahim; Giri, Fouad; El Magri, Abdelmounime; Dugard, Luc; Chaoui, Fatima Zara

    2012-01-01

    The problem of controlling induction motors, together with associated AC/DC rectifiers and DC/AC inverters, is addressed. The control objectives are threefold: (i) the motor speed should track any reference signal despite mechanical parameter uncertainties and variations; (ii) the DC Link voltage must be tightly regulated; (iii) the power factor correction (PFC) w.r.t. the power supply net must be performed in a satisfactory way. First, a nonlinear model of the whole controlled system is deve...

  1. Robust control of synchronous motors through AC/DC/AC converters

    El Magri, Abdelmounime; Giri, Fouad; Abouloifa, Abdelmajid; Chaoui, Fatima Zara

    2010-01-01

    The problem of controlling synchronous motors, driven through AC/DC rectifiers and DC/AC inverters is addressed. The control objectives are three fold: (i) forcing the motor speed to track a varying reference signal in presence of motor parameter uncertainties;(ii) regulating the DC Link voltage; (iii )assuring a satisfactory power factor correction (PFC) with respect to the power supply net .First, a nonlinear model of the whole controlled system is developed in the Park-coordinates. Then, a...

  2. A new class of hybrid AC/AC direct power converters

    Klumpner, Christian; Wijekoon, Thiwanka; Wheeler, Patrick

    2005-01-01

    Variable voltage and variable frequency conversion of electrical energy from an AC source to an AC load is done in traditional power converters via a DC-link where an energy storage element (electrolytic capacitors) is situated. Despite its well-known benefits, it has the disadvantage of being bulky and to limit the converter lifetime. On the other hand, Direct Power Conversion (DPC) is an attractive concept, which doesn’t need an energy storage buffer, but has two main disadvantages: reduced...

  3. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion...... will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration....

  4. AC losses in a HTS coil carrying DC current in AC external magnetic field

    We electrically measured AC losses in a Bi2223/Ag-sheathed pancake coil excited by a DC current in AC external magnetic field. Losses in the coil contain two kinds of loss components that are the magnetization losses and dynamic resistance losses. In the measurement, current leads to supply a current to the coil were specially arranged to suppress electromagnetic coupling between the coil current and the AC external magnetic field. A double pick-up coils method was used to suppress a large inductive voltage component contained in voltage signal for measuring the magnetization losses. It was observed that the magnetization losses were dependent on the coil current and that a peak of a curve of the loss factor vs. amplitude of the AC external magnetic field shifted to lower amplitude of the AC magnetic field as the coil current increased. This result suggests the full penetration magnetic field of the coil tape decreases as the coil current increases. The dynamic resistance losses were measured by measuring a DC voltage appearing between the coil terminals. It was observed that the DC voltage appearing in the coil subject to the AC external magnetic field was much larger than that in the coil subject to DC magnetic field

  5. 21 CFR 880.5500 - AC-powered patient lift.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  6. AC LED的研究现状与发展%Current research and development of AC LED

    满瑞; 李秋俊

    2012-01-01

    介绍了AC LED的特征及其工作原理,分析了AC LED相比于DC LED的优缺点,概述了AC LED在国内外的研究进展及其应用现状,讨论了AC LED技术发展过程中面临的挑战,并展望了其发展趋势.%The characteristics and operation principles of AC LED were presented.The advantages and disadvantages of AC LED compared with the DC LED were analyzed.The development and the latest application of AC LED were described.The challenges of the competition with the traditional light source were discussed,as well as the development trend of AC LED.

  7. Dicty_cDB: FCL-AC08 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC08 (Link to dictyBase) - - - Contig-U15080-1 FCL-AC08P ...(Link to Original site) FCL-AC08F 616 FCL-AC08Z 291 FCL-AC08P 907 - - Show FCL-AC08 Library FCL (Link to library) Clone ID FCL-...-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC08Q....Seq.d/ Representative seq. ID FCL-AC08P (Link to Original site) Representative DNA sequence >FCL-AC08 (FCL-AC08Q) /CSM/FCL/FCL-...ignificant alignments: (bits) Value FCL-AC08 (FCL-AC08Q) /CSM/FCL/FCL-AC/FCL-AC08Q.Seq.d/ 1322 0.0 SFA226 (S

  8. Fractional ac Josephson effect in unconventional superconductors

    For certain orientations of Josephson junctions between two px-wave or two d-wave superconductors, the subgap Andreev bound states produce a 4π-periodic relation between the Josephson current I and the phase difference ψ: I propor to sin(ψ/2) . Consequently, the ac Josephson current has the fractional frequency eV/h where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction

  9. AC motor drive system for electric cars

    Morohoshi, Yukinobu; Yoshinori, Naoto; Naito, Hironobu (Fuji Electric Co., Ltd., Tokyo, (Japan))

    1989-08-10

    Various main circuit equipment with large capacity GTO thyristors are outlined for AC and DC electric cars. The configuration of a PWM converter system is presented for the AC main motor drive system of the Shinkansen trains, and its following features are described: the high power factor control capable of keeping a power factor 100% constantly, energy saving by power regenerative braking, the small triple structure with large capacity reverse-conducting GTO thyristors of 4,500V/3,000A, and the reduction of equivalent interfering current and harmonic current by three phase-triple phase difference operation. Furthermore, a control logic equipment with 16 bit MPU and a main transformer are outlined, and the verification test results of the control logic equipment by an analog model simulation and the combinational test results of the commercial equipment are reported. Prototype VVVF inverter system for DC electric cars is also presented. 6 refs., 13 figs., 3 tabs.

  10. β-delayed fission from 230Ac

    ThO2 is irradiated with 60 MeV/u 18O beams. 230Ra is produced via the multi-nucleon transfer and dissipative fragmentation reactions of the target. 230Ra is radio-chemical separated from ThO2 and the other reaction products. The thin Ra sources are prepared. The mica fission track detectors are exposed to the Ra sources. γ-rays of Ra decay in the sources are measured by a HPGe detector. The mica foil is etched in HF solution. The etched mica foil is scanned with an optical microscope. The fission tracks that should come from β-delayed fission of 230Ac are observed. The β-delayed fission probability of 230Ac is determined to be (1.19 +- 0.85) x 10-8

  11. AC Dielectrophoresis Using Elliptic Electrode Geometry

    S. M. Rezaul Hasan; Aanan Khurma

    2011-01-01

    This paper presents negative AC dielectrophoretic investigations using elliptic electrode geometry. Simulations of the electric field gradient variation using various ratios of the semimajor and the semiminor axis were carried out to determine the optimum elliptic geometry for the dielectrophoretic electrokinetics of specimen in an assay with laminar (low Reynolds number) fluid flow. Experimental setup of the elliptic electrode assembly using PCB fabrication and electrokinetic accumulation of...

  12. Lazy AC-Pattern Matching for Rewriting

    Belkhir, Walid; 10.4204/EPTCS.82.3

    2012-01-01

    We define a lazy pattern-matching mechanism modulo associativity and commutativity. The solutions of a pattern-matching problem are stored in a lazy list composed of a first substitution at the head and a non-evaluated object that encodes the remaining computations. We integrate the lazy AC-matching in a strategy language: rewriting rule and strategy application produce a lazy list of terms.

  13. Entropy production in ac-calorimetry

    Garden, Jean-Luc; Richard, Jacques

    2007-01-01

    In calorimetry and particularly in heat capacity measurements, different characteristic relaxation time constants may perturb the experiment which cannot be considered at thermodynamic equilibrium. In this case, thermodynamics of irreversible processes has to be taken into account and the calorimetric measurements must be considered as dynamic. In a temperature modulated experiment, such as ac-calorimetry, these non-equilibrium experiments give rise to the notion of frequency dependent comple...

  14. Development of a hardware-based AC microgrid for AC stability assessment

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  15. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    S. Arumugam S. Ramareddy M. Sridhar

    2011-12-01

    Full Text Available This paper presents a novel soft-switching pulse width modulation (PWM utility frequency AC to high frequency (HF AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching operation ranges.. The simulation circuits are models are developed and they are simulated using ORCAD.

  16. Implementation and Control of an AC/DC/AC Converter for Double Wound Flywheel Application

    Oliveira, J. G.; Schettino, H.; Gama, V; Carvalho, R.; H. Bernhoff

    2012-01-01

    An all-electric driveline based on a double wound flywheel, connected in series between main energy storage and a wheel motor, is presented. The flywheel works as a power buffer, allowing the battery to deliver optimized power. It also separates electrically the system in two sides, with the battery connected to the low voltage side and the wheel motor connected to the high voltage side. This paper presents the implementation and control of the AC/DC/AC converter, used to connect the flywheel...

  17. GRID-CONNECTECD DOUBLE-STAGE AC-AC POWER CONVERTER FOR CSP RENEWABLE ENERGY SYSTEMS

    Sorrentino, Vincenzo

    2015-01-01

    In the last years the renewable energy sources have known a state of their advanced diffusion considering their advantages compared to the traditional energy sources like fossil fuels. For this reason the combined heat and power (CHP) plant fueled by renewable sources are widely used. The purpose of this Ph.D. thesis is the design of a new Grid-connected Double-Stage AC-DC/DC-AC Power Converter (DSACPC) for a Concentrating Solar plant for Combined generation of Heat and Power (CS-CHP), th...

  18. AcEST Contig - AcEST | LSDB Archive [Life Science Database Archive metadata

    Full Text Available [ Credit s ] BLAST Search Image Search Home About Archive Update History Contact us AcEST AcEST C ... c.jp/togodb/view/archive_acestcontig#en Data acquisit ion method - Data analysis method - Number of data ... entries 4,298 entries Data it em Description Contig ID ID of contig sequence of A ... ris Number of clones The number of EST clones constit uting the contig sequence of Adiantum capillus-vene ... ris Definit ion Definit ion Link to clone list In the TogoDB edi ...

  19. Realization of a Direct Soft Switching AC/AC Converter for Wireless Power Transfer Applications

    Vuorsalo, Simo

    2015-01-01

    This thesis describes the design, realization and testing of a three-phase to one-phase direct AC/AC converter, also known as the matrix converter. The switching is using the soft-switching strategy which is also known in the literature as the Zero Current Switching strategy. To achieve ZCS, the circuit needs resonant behavior which is achieved by the transmitter primary side that is an LC circuit. This circuit acts as a tank circuit and the switching frequency is the resonant frequency of th...

  20. Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count

    Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;

    2007-01-01

    This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled to...... low cost alternative to sensitive applications that need to ride-through frequent input voltage sags. For confirming the converter performance, experimental testing using a constructed laboratory prototype is performed with its captured results presented in a later section of the paper....

  1. Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count

    Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;

    2009-01-01

    This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low-cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled to...... semiconductor commutations, and hence, no increase in switching losses. The proposed converter therefore offers a low-cost alternative to applications that need to ride through frequent input voltage sags. For confirming the converter performance, experimental testing using a constructed laboratory prototype is...

  2. Dicty_cDB: FCL-AC03 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC03 (Link to dictyBase) - - - Contig-U16477-1 FCL-AC03P ...(Link to Original site) FCL-AC03F 538 FCL-AC03Z 570 FCL-AC03P 1108 - - Show FCL-AC03 Library FCL (Link to library) Clone ID FCL-...7-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC03Q....Seq.d/ Representative seq. ID FCL-AC03P (Link to Original site) Representative DNA sequence >FCL-AC03 (FCL-AC03Q) /CSM/FCL/FCL-...AC/FCL-AC03Q.Seq.d/ AATTTTTAAAAAAAAAAGAAAATAAAAAAAAAAATAATATTTTATTAGTCATTATAAAAT TGTGAAT

  3. Dicty_cDB: FCL-AC20 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC20 (Link to dictyBase) - - - Contig-U15117-1 FCL-AC20Z ...(Link to Original site) - - FCL-AC20Z 600 - - - - Show FCL-AC20 Library FCL (Link to library) Clone ID FCL-A... http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC20Q.Seq.d/ Representative seq. ID FCL-...AC20Z (Link to Original site) Representative DNA sequence >FCL-AC20 (FCL-AC20Q) /CSM/FCL/FCL-AC/FCL-...Homology vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value FCL-AC20 (FCL-AC20Q) /CSM/FCL/FCL-AC/FCL-

  4. Levantamiento del campo acústico de una fuente sonora subacuática en el tanque hidroacústico del Instituto de Acústica

    Ranz Guerra, Carlos; Cobo, Pedro

    2000-01-01

    6 pp.-- PACS nrs.: 43.30.Jx, 43.30.Sf.-- Comunicación presentada en los siguientes congresos: Acústica 2000, II Congreso Iberoamericano de Acústica. XXXI Congreso Nacional de Acústica: TecniAcústica 2000. II Congreso Ibérico de Acústica. II Jornadas Iberoamericanas de Acústica. EAA Symposium on Architectural Acoustics.

  5. DC injection into low voltage AC networks

    NONE

    2005-07-01

    This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.

  6. Mapa acústico parcial de Benetusser

    MORILLA CASTELLANOS, EMILIO

    2012-01-01

    Se establece el mapa de ruido del municipio de Benetússer para evaluar y conocer su exposición al ruido ambiental y así poder dar cumplimiento a la Directiva Europea sobre Gestión y Evaluación de Ruido Ambiental (2002/49/CE) y a la Ley nacional 37/2003 del Ruido. Los mapas estratégicos de ruido nos aportan la información fundamental para diagnosticar la situación acústica y para la gestión del ruido ambiental.

  7. An ac biased superconducting flux transformer

    The coupled motion of the vortex lattice of two electrically insulated, superimposed, superconducting thin films (primary and secondary) in a perpendicular magnetic field, is predicted to exhibit a Josephson-like behavior. For a dc applied current flowing in the primary film, the voltage difference between the time-averaged primary and secondary flux flow voltages obeys the equations of a resistively shunted junction model. If an ac current is superimposed on the dc current. Shapiro-type steps are predicted in the current-voltage characteristic. In contrast to the conventional Josephson effect, the voltage positions of these steps can be tuned by the applied magnetic field. (orig.)

  8. Flexible AC transmission systems modelling and control

    Zhang, Xiao-Ping; Pal, Bikash

    2012-01-01

    The extended and revised second edition of this successful monograph presents advanced modeling, analysis and control techniques of Flexible AC Transmission Systems (FACTS). The book covers comprehensively a range of power-system control problems: from steady-state voltage and power flow control, to voltage and reactive power control, to voltage stability control, to small signal stability control using FACTS controllers. In the six years since the first edition of the book has been published research on the FACTS has continued to flourish while renewable energy has developed into a mature and

  9. Estudio acústico del Conservatorio de Piles

    VILLA MORANT, SARA

    2014-01-01

    El objetivo de este proyecto es realizar un estudio acústico general de la "Casa de la Cultura" de Piles, sobre todo de los recintos que más lo requieren, como la sala principal de música. El edificio, al tratarse de una construcción antigua, no reúne las especificaciones acústicas establecidas en el Código Técnico vigente en la actualidad. En primer lugar, se realiza el estudio del acondicionamiento acústico de la sala principal, entendiéndose como acondicionamiento acústico la definición de...

  10. AC Own Motion Percentage of Randomly Sampled Cases

    Social Security Administration — Longitudinal report detailing the numbers and percentages of Appeals Council (AC) own motion review actions taken on un-appealed favorable hearing level decisions...

  11. AC electric motors control advanced design techniques and applications

    Giri, Fouad

    2013-01-01

    The complexity of AC motor control lies in the multivariable and nonlinear nature of AC machine dynamics. Recent advancements in control theory now make it possible to deal with long-standing problems in AC motors control. This text expertly draws on these developments to apply a wide range of model-based control designmethods to a variety of AC motors. Contributions from over thirty top researchers explain how modern control design methods can be used to achieve tight speed regulation, optimal energetic efficiency, and operation reliability and safety, by considering online state var

  12. Study of AC electrical conduction mechanisms in an epoxy polymer

    Jilani, Wissal; Mzabi, Nissaf; Gallot-Lavallée, Olivier; Fourati, Najla; Zerrouki, Chouki; Zerrouki, Rachida; Guermazi, Hajer

    2015-11-01

    The AC conductivity of an epoxy resin was investigated in the frequency range 10^{-1} - 106 Hz at temperatures ranging from -100 to 120 °C. The frequency dependence of σ_{ac} was described by the law: σ_{ac}=ω \\varepsilon0\\varepsilon^''_{HN}+Aωs. The study of temperature variation of the exponent (s) reveals two conduction models: the AC conduction dependence upon temperature is governed by the small polaron tunneling mechanism (SPTM) at low temperature (-100 -60 °C) and the correlated barrier hopping (CHB) model at high temperature (80-120 °C).

  13. Djungle power. A more remote AC bus

    Boehnke, Heinz W. [Technosol, Jork (Germany)

    2010-07-01

    The Dzanga-Sangha Reserve in the Central African Republic is probably one of the world's most remote protected rainforest areas, much to the benefit of the rare species of lowland gorilla, forest elephant and local pygmy population Ba'Aka. The park is co-managed by the ''WWF-World Wide Fund for Nature'' with sponsoring from the German Regenwald-Stiftung. In 2008 wwf decided to switch from the old, failing generator supply to a solar hybrid mini-grid, along with stringent measures of energy conservation and management. After a careful energy audit Technosol designed an AC-bus system with a 22 kWp PV generator which should overcome the dependency on the old generators and their fuel demands. For 15 buildings, an entirely new distribution network was installed, state of the art energy saving devices introduced and an energy metering system deviced. The installation is operating since August 2009. In such remote locations, the reliability of the AC-bus over other generator-based solutions will be demonstrated and with the support of international organisations like the wwf the practical application of solar hybrid supply becomes a landmark of sustainable energy concepts. (orig.)

  14. An improved AC-amplifier for electrophysiology

    Jorgovanović Nikola

    2009-01-01

    Full Text Available We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA. The design target was to increase the common mode rejection ratio (CMRR, thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier's first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper.

  15. Dicty_cDB: FCL-AC29 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC29 (Link to dictyBase) - - - Contig-U15392-1 FCL-AC29P ...(Link to Original site) FCL-AC29F 104 FCL-AC29Z 591 FCL-AC29P 695 - - Show FCL-AC29 Library FCL (Link to library) Clone ID FCL-...-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC29Q....Seq.d/ Representative seq. ID FCL-AC29P (Link to Original site) Representative DNA sequence >FCL-AC29 (FCL-AC29Q) /CSM/FCL/FCL-...roducing significant alignments: (bits) Value VSC293 (VSC293Q) /CSM/VS/VSC2-D/VSC293Q.Seq.d/ 1063 0.0 FCL-AC29 (FCL-

  16. A Non-linear Controller for Single-Phase AC-AC Power Converter to meet UPS Performance Index

    Abdelhafid Ait Elmahjoub

    2012-07-01

    Full Text Available This article focuses on AC-AC power converter that can be used for uninterruptible power supply (UPS. The converter is built on two stages: a AC-DC input stage and a DC-AC output stage. The two blocks are connected by an intermediate DC bus. The aim of control is threefold: i power factor correction ii regulation of DC bus iii generating a sinusoidal voltage at the output. The synthesis of controllers has been achieved through the technique of nonlinear backstepping control. A detailed analysis of the stability control system is presented. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.

  17. [Intestinal occlusion and abdominal compartment syndrome (ACS)].

    Stagnitti, Franco

    2009-01-01

    Intestinal occlusion is defined as an independent predictive factor of intra-abdominal hypertension (IAH) which represents an independent predictor of mortality. Baggot in 1951 classified patients operated with intestinal occlusion as being at risk for IAH ("abdominal blow-out"), recommending them for open abdomen surgery proposed by Ogilvie. Abdominal surgery provokes IAH in 44.7% of cases with mortality which, in emergency, triples with respect to elective surgery (21.9% vs 6.8%). In particular, IAH is present in 61.2% of ileus and bowel distension and is responsible for 52% of mortality (54.8% in cases with intra-abdominal infection). These patients present with an increasing intra-abdominal pressure (IAP) which, over 20-25 mmHg, triggers an Abdominal Compartment Syndrome (ACS) with altered functions in some organs arriving at Multiple Organ Dysfunction Syndrome (MODS). The intestine normally covers 58% of abdominal volume but when there is ileus distension, intestinal pneumatosis develops (third space) which can occupy up to 90% of the entire cavity. At this moment, Gastro Intestinal Failure (GIF) can appear, which is a specific independent risk factor of mortality, motor of "Organ Failure". The pathophysiological evolution has many factors in 45% of cases: intestinal pneumatosis is associated with mucosal and serous edema, capillary leakage with an increase in extra-cellular volume and peritoneal fluid collections (fourth space). The successive loss of the mucous barrier permits a bacterial translocation which includes bacteria, toxins, pro-inflammatory factors and oxygen free radicals facilitating the passage from an intra-abdominal to inter-systemic vicious cyrcle. IAH provokes the raising of the diaphragm, and vascular and visceral compressions which induce hypertension in the various spaces with compartmental characteristics. These trigger hypertension in the renal, hepatic, pelvic, thoracic, cardiac, intracranial, orbital and lower extremity areas, giving

  18. Cooperative Frequency Control for Autonomous AC Microgrids

    Shafiee, Qobad; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.; Nasirian, Vahidreza; Davoudi, Ali

    2015-01-01

    Distributed secondary control strategies have been recently studied for frequency regulation in droop-based AC Microgrids. Unlike centralized secondary control, the distributed one might fail to provide frequency synchronization and proportional active power sharing simultaneously, due to having...... different control parameters. This paper introduces a cooperative algorithm that regulates the system frequency while maintaining the power sharing properties of droop control. Dynamic consensus protocol is used to estimate the average of normalized active powers in the entire MG. This estimation is then...... added to primary control, compensating the frequency drop caused by the droop mechanism. The proposed controller is fully distributed, meaning that each source exchange information with only its direct neighbors through a sparse communication network. This controller has a unique feature that it does...

  19. Mapa Acústico del Gran Madrid

    Santiago Páez, José Salvador; Perera, P

    2006-01-01

    El desarrollo urbanístico de Madrid desde los años 1980 a finales de la década de los 90 hizo que su Ayuntamiento, que ya había promovido la realización entre 1985 y 1991 de un Mapa Acústico parcial de la ciudad, pensase en extender el ámbito de éste a todo el término municipal. Siguiendo el mismo criterio anterior, se superpuso una cuadrícula sobre el plano de Madrid, y se llevaron a cabo registros sonoros de 5 minutos en cada vértice de la misma, en los puntos de medición fuera del área ant...

  20. Josephson arrays for dc and ac metrology

    Large series arrays of underdamped SIS tunnel junctions are the basic element of the primary dc voltage standards used at present. The development of versatile quantum voltmeters for dc and ac metrology requires the preparation of large and perfect series arrays of overdamped Josephson junctions. Overdamped junctions can be realized by externally shunted SIS junctions or by internally shunted SNS or SINIS junctions. Arrays of up to 8000 SINIS junctions or 30000 SNS junctions were successfully operated at the 1 V dc level. In addition to being used in large arrays for voltage metrology and oscillators, the described junction types may become very useful for the preparation of highly integrated single-flux-quantum digital devices. (author)

  1. An ac bridge readout for bolometric detectors

    Rieke, F. M.; Lange, A. E.; Beeman, J. W.; Haller, E. E.

    1989-01-01

    The authors have developed a bolometer readout circuit which greatly improves the low-frequency stability of bolometric detectors. The circuit uses an ac bias voltage and two matched bolometers and allows stable dc bolometer operation for integration times greater than 10 s. In astronomical applications the readout allows for qualitatively different observation modes (e.g. staring or slow-drift scanning) which are particularly well suited for space observations and for the use of arrays. In many applications the readout can increase sensitivity. The authors present noise spectra for 4He temperature bolometers with no excess noise at frequencies greater than 0.1 Hz. The measured optical responsivity of a bolometer operated with the present readout is the same as that of a bolometer operated with a conventional readout.

  2. Composite Based EHV AC Overhead Transmission Lines

    Sørensen, Thomas Kjærsgaard

    Overhead lines at transmission level are the backbone of any national power grid today. New overhead line projects however are at the same time subject to ever greater public resistance due to the lines environmental impact. As full undergrounding of transmission lines at extra high voltage (EHV......) levels are still not seen as possibility, the future expansion of transmission grids are dependent on new solutions with lessened environment impact, especially with regard to the visual impact. In the present Thesis, composite materials and composite based overhead line components are presented and...... analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...

  3. Effective ac response in weakly nonlinear composites

    Wei Enbo [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Yang Zidong [College of Power Engineering, University of Shanghai Science and Technology, Shanghai 200093 (China); Gu Guoqing [Information College of Science and Technology, East China Normal University, Shanghai 200062 (China)

    2004-01-07

    The perturbation method is developed to deal with the problem of determining the effective nonlinear conductivity of Kerr-like nonlinear media under an external ac electric field. As an example, we have considered the cylindrical inclusion embedded in a host under the sinusoidal external field E{sub 1} sin (<{omega}t) + E{sub 3} sin (3<{omega}t) with frequencies{omega} and 3{omega}. The potentials of composites at higher harmonics are derived in both local inclusion particle and host regions. The effective responses of bulk nonlinear composites at basic frequency and harmonics are given for cylindrical composites in the dilute limit. Moreover, the relationships between the nonlinear effective responses at the basic frequency and the third harmonics are derived.

  4. Modeling of long High Voltage AC Underground

    Gudmundsdottir, Unnur Stella; Bak, Claus Leth; Wiechowski, W. T.

    2010-01-01

    This paper presents the work and findings of a PhD project focused on accurate high frequency modelling of long High Voltage AC Underground cables. The project is cooperation between Aalborg University and Energinet.dk. The objective of the project is to investigate the accuracy of most up to date...... cable models, perform highly accurate field measurements for validating the model and identifying possible disadvantages of the cable model. Furthermore the project suggests and implements improvements and validates them against several field measurements. It is shown in this paper how a new method for...... calculating the frequency dependent cables impedance greatly improves the modeling procedure and gives a highly accurate result for high frequency simulations....

  5. Nonlinear ac conductivity of interacting 1d electron systems

    Rosenow, Bernd; Nattermann, Thomas

    2004-01-01

    We consider low energy charge transport in one-dimensional (1d) electron systems with short range interactions under the influence of a random potential. Combining RG and instanton methods, we calculate the nonlinear ac conductivity and discuss the crossover between the nonanalytic field dependence of the electric current at zero frequency and the linear ac conductivity at small electric fields and finite frequency.

  6. Flexible AC transmission systems: the state of the art

    Edris, Abdel-Aty [Electric Power Research Inst., Palo Alto, CA (United States). Electric Systems Division

    1994-12-31

    Flexible AC transmission systems (FACTS) is a concept promoting the use of power electronic controllers to enhance the controllability and usable capacity of AC transmission. This paper presents the state of the art of FACTS and the status of the current projects for the application of the FACTS controllers in transmission systems. (author) 8 refs., 8 figs.

  7. 78 FR 39345 - ACS Wireless, Inc.; Notice of Application

    2013-07-01

    ... will transfer to AWN all remaining tangible and intangible assets owned, leased or held by ACS Wireless.... \\6\\ ACS Group will cause certain of its other subsidiaries to transfer wireless spectrum licenses and...'' as the power to exercise a controlling influence over the management or policies of a company,...

  8. Operation of AC Adapters Visualized Using Light-Emitting Diodes

    Regester, Jeffrey

    2016-01-01

    A bridge rectifier is a diamond-shaped configuration of diodes that serves to convert alternating current(AC) into direct current (DC). In our world of AC outlets and DC electronics, they are ubiquitous. Of course, most bridge rectifiers are built with regular diodes, not the light-emitting variety, because LEDs have a number of disadvantages. For…

  9. Search for β-delayed fission of 228Ac

    Radium was radiochemically separated from natural thorium. Thin 228Ra→β-228Ac sources were prepared and exposed to mica fission track detectors, and measured by an HPGe γ-ray detector. The β-delayed fission events of 228Ac were observed and its β-delayed fission probability was found to be (5±2)x10-12

  10. Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

    Qin, Zian

    proposed new active power decoupling method, the ripple power in the converter can be compensated in a more efficient and more compact way. Then, Chapter 5 changes the scope of the thesis to three-phase converters, and the nine-switch converter, as a reduced switch version of two three-phase full......-bridges connected back-to-back, is studied. Application criteria of the nine-switch converter are investigated for reducing the relatively high stress introduced by the less number of switches. In Chapter 6 a rotating speed controller design method is proposed for improving the thermal loading of the three...... to users. Their performances including cost, efficiency, reliability, and so on, therefore are more important concerns than they were. The objective of this thesis is to study and propose advanced design methods for robust ac-dc-ac converters, which are widely used interfaces in energy conversion...

  11. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    2010-07-01

    ... Procedures § 86.162-00 Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2. The alternative air conditioning test procedures AC1 and AC2 are approved by the Administrator... requirements of paragraph (a) of this section and meet the requirements of § 86.163-00. Air conditioning...

  12. Determination for β-delayed fission probability of 230Ac

    袁双贵; 杨维凡; 徐岩冰; 肖永厚; 罗亦孝

    2002-01-01

    The 230Ra has been produced via 232Th-2p reaction induced by 60 MeV/u 18O ion irradia-tion of natural thorium. The radium was radiochemically separated from the mixture of thorium andreaction products. Thin Ra sources in which 230Ac was got through 230Ra β- → 230Ac were pre-pared for observing fission fragments from β-delayed fission of 230Ac. The sources were exposedto the mica fission track detectors and measured by the HPGe γ detector. The precursor 230Ac wasidentified by means of observed two fission events as well as γ spectra, and the β-delayed fissionprobability of 230Ac was obtained to be (1.19±0.85) × 10-8.

  13. Development of YBCO HTS cable with low AC loss

    High temperature superconducting (HTS) cables using YBCO tapes are expected to be more economical because AC losses will be much smaller than conventional cables. To reduce AC loss, 10 mm wide YBCO tapes were divided into five strips using a YAG laser. Using narrower strips and optimizing the space between the strips were effective in reducing AC loss. A 1 m conductor was fabricated, and AC loss was 0.048 W/m at 1 kA and 50 Hz. Based on the successful AC loss reduction in the 1 m conductor, we will fabricate a 10 m HTS cable with a three-layer HTS conductor, electrical insulation, and a one-layer HTS shield and cupper protection layer for overcurrent. In addition, we have developed a prototype of the HTS cable joint that can withstand an overcurrent condition of 31.5 kA for 2 s

  14. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær;

    2012-01-01

    performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity...... bladder 18 ± 3% (15–21%). The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of...... the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction....

  15. Ac response of a coupled double quantum dot

    Xu Jie; W.Z. Shangguan; Zhan Shi-Chang

    2005-01-01

    The effect of phase-breaking process on the ac response of a coupled double quantum dot is studied in this paper based on the nonequilibrium Green function formalism. A general expression is derived for the ac current in the presence of electron-phonon interaction. The ac conductance is numerically computed and the results are compared with those in [Anatram M P and Datts S 1995 Phys. Rev. B 51 7632]. Our results reveal that the inter-dot electron tunnelling interplays with that between dots and electron reservoirs, and contributes prominently to the ac current when inter-dot tunnelling coupling is much larger than the tunnelling coupling between dots and electron reservoirs. In addition, the phase-breaking process is found to have a significant effect on the ac transport through the coupled double dot.

  16. A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System

    Marian GAICEANU

    2003-12-01

    Full Text Available In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller 30 MIPS 32-bit fixed-point digital signal processor (DSP, were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation at the load changes can be reduced. In this way a small DC link capacitor is required to handle the dc voltage error control. The feed-forward (Sul and Lipo, 1990 current component provides fast correction of the reference control to load power variation. In order to obtain the feed-forward current component, the load power must to be known. In this paper the load power is estimated from the dc link, indirectly, through a dc load current estimator. In this way the author overcomes the use of the serial communication between control boards (Gaiceanu, 2004 in order to deliver the load power information from the inverter side. The load current estimator is based on the DC link voltage and on the load current of the supply converter. This method presents certain advantages instead of using measured method, which requires a low pass filter: no time delay, the feed-forward current component has no ripple, no additional hardware, and more fast control response. Through simulation and experimental results the performances of the proposed load current estimator scheme are demonstrated.

  17. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  18. Sustainable AC/AC hybrid electrochemical capacitors in aqueous electrolyte approaching the performance of organic systems

    Abbas, Qamar; Babuchowska, Paulina; Frąckowiak, Elżbieta; Béguin, François

    2016-09-01

    A high energy hybrid AC/AC electrochemical capacitor has been realized in aqueous Li2SO4+KI electrolyte mixture. Owing to the redox processes associated with the 2I-/I2 system, the positive electrode operates in narrow potential range and displays high capacity. During prolonged potentiostatic floating at 1.6 V, the hybrid cell demonstrates remarkably stable capacitance and resistance. Analyses by temperature programmed desorption after floating at 1.6 V proved that oxidation of the positive AC electrode is prevented by the use of Li2SO4+KI, which enables the maximum potential of this electrode to be shifted below the water oxidation potential. When charged at 0.2 A g-1 up to U = 1.6 V, the hybrid cell displays a high capacitance of 75 F g-1 (300 F g-1 per mass of one electrode) compared to 47 F g-1 (188 F g-1 per mass of one electrode) for a symmetric cell in Li2SO4. At 0.2 A g-1 up to 1.6 V, the hybrid capacitor in Li2SO4+KI displays an energy density of 26 Wh kg-1 which approaches the energy density of 30.9 Wh kg-1 measured when the same carbon is implemented in a capacitor using TEABF4/ACN electrolyte and charged up to 2.5 V.

  19. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach it is not...

  20. La acústica submarina y su desarrollo desde la creación del Instituto de Acústica

    Ranz Guerra, Carlos; Cobo, Pedro; Carbó, Rafael; Santiago Páez, José Salvador; Soler, A. M.; Briones, J. M.; Jimeno, I.; Muñoz, N; Camarasa, M.; Recuero López, Manuel

    2000-01-01

    PACS: 43.30.Xm; 43.30.Yj; 43.30.Vh; 43.30.Nb; 43.30.Ma.-- Publicado en el Vol. XXXI, núm. 3-4, tercer y cuarto trimestre 2000 de la Revista de Acústica: Número especial dedicado al XXV Aniversario del Instituto de Acústica del C.S.I.C.

  1. Numerical estimation of AC loss in superconductors with ripple current

    Highlights: •The loss energy density with ripple current is numerically calculated. •Irie–Yamafuji model is used for magnetic field dependence of critical current. •Calculated result of cylindrical superconductor agrees with theoretical result. •AC loss of strip superconductor becomes large at small ripple current amplitude. •Strip superconductor should be used as a form of hollow cylinder to reduce AC loss. -- Abstract: The loss energy density (AC loss) with ripple current is numerically calculated by finite element method for cylindrical and strip superconductors based on Irie–Yamafuji model in which the magnetic field dependence of the critical current density is taken into account for design of DC transmission cable system. It is confirmed that calculated result of the AC loss in the cylindrical superconductor with the ripple current agrees well with theoretical estimation which was reported in the previous work. On the contrary, the AC loss in the strip superconductor with the ripple current is obtained only by numerical calculation. It is found that the AC loss in the strip superconductor of the ripple current becomes larger than that without DC current at small ripple current amplitude, since the penetration depth of magnetic field becomes large. Therefore, it is recommended that strip superconductor is better to use as cylindrical hollow superconductor for DC transmission cable system to reduce the AC loss

  2. Importance of Attenuation Correction (AC for Small Animal PET Imaging

    Henrik H. El Ali

    2012-10-01

    Full Text Available The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7 were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II. CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%, for kidneys 20 ± 1% (19–21%, and for bladder 18 ± 3% (15–21%. The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction.

  3. Analytical description of AC losses for high temperature superconductors

    Full text: AC losses for high temperature superconductors have been calculated by considering the effects of the temperature distribution and the flux flow resistance. Maxwell's equations and thermal diffusion equation are used to calculate the distribution of magnetic field and the temperature inside the superconductors, respectively. The flux flow effect on the AC losses is calculated by using the extended critical state model. An analytical expression of the AC losses is obtained using a superposition approximation in which the cases of complete and incomplete magnetic field penetration have been distinguished. The expression can well explain the experimental observations of the frequency dependence of the AC losses per cycle in high temperature superconductors. It is clearly shown from the analytical expression that the effect of the thermal distribution inside the superconductors is different from the effect caused by flux flow resistance. In the case of incomplete magnetic penetration, the temperature distribution results in the increase of the AC losses per cycle upon frequency whereas the flux flow leads to the decrease of the AC losses per cycle upon frequency. In the case of complete magnetic penetration the results are opposite to those in the previous case. Due to the extremely strong flux flow in high temperature superconducting materials, the effect of the flux flow on the AC losses is dominant, and the overall dependence of AC losses per cycle upon frequency is controlled by the flux flow. On the other hand, because the inhomogeneous distribution of the temperature inside the superconductors which is normal higher in the center than near the edge, there is an upper limit for the frequency beyond which the superconductivity will be totally destroyed by AC losses. Analytical expressions for the critical frequency, distributions of magnetic field and critical current density are also obtained

  4. Operation of AC Adapters Visualized Using Light-Emitting Diodes

    Regester, Jeffrey

    2016-01-01

    A bridge rectifier is a diamond-shaped configuration of diodes that serves to convert alternating current (AC) into direct current (DC). In our world of AC outlets and DC electronics, they are ubiquitous. Of course, most bridge rectifiers are built with regular diodes, not the light-emitting variety, because LEDs have a number of disadvantages. For educational purposes, however, an LED-based rectifier is ideal because it allows students to literally see the rectifier operating. Here I'll discuss the practical aspects of building a full AC adapter incorporating an LED-based rectifier and ideas on how to use it in class.

  5. Theoretical analysis of ac losses in high temperature superconducting bulks

    Ac loss behavior in HTS bulk materials is studied by developing an analytic method. The self-heating effect on the distributions of temperature in HTS bulks has been calculated. A critical frequency which sets the upper limit for driving frequency of the external field in sustaining a superconducting state is obtained. Our model provides useful information of understanding the experimental phenomena, including an anomalous ac loss behavior, a retardation of the inner field respect to the external ac field, etc., in HTS bulk materials

  6. Advanced DC/AC inverters applications in renewable energy

    Luo, Fang Lin

    2013-01-01

    DC/AC inversion technology is of vital importance for industrial applications, including electrical vehicles and renewable energy systems, which require a large number of inverters. In recent years, inversion technology has developed rapidly, with new topologies improving the power factor and increasing power efficiency. Proposing many novel approaches, Advanced DC/AC Inverters: Applications in Renewable Energy describes advanced DC/AC inverters that can be used for renewable energy systems. The book introduces more than 100 topologies of advanced inverters originally developed by the authors,

  7. Analysis of Input and Output Ripples of PWM AC Choppers

    Pekik Argo Dahono

    2008-11-01

    Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.

  8. An Improved AC-BM Algorithm for Monitoring Watch List

    Mo Yiwen

    2013-07-01

    Full Text Available With the expanding of database of the watch list of anti-money laundering, improving the speed in matching between the watch list and the database of account holders and clients’ transaction is especially important. This paper proposes an improved AC-BM Algorithm, a matching algorithm of subsection, to improve the speed of matching. Experiment results show the time performance of the improved algorithm is better than traditional BM algorithm, AC algorithm and the AC-BM algorithm. It can improve the efficiency of on-line monitoring of anti-money laundering.  

  9. DC and AC biasing of a transition edge sensor microcalorimeter

    We are developing AC-biased transition edge sensor (TES) microcalorimeters for use in large arrays with frequency-domain multiplexing. Using DC bias, we have achieved a resolution of 17 eV FWHM at 2.6 keV with a decay time of 90 μs and an effective detector diameter of 300 μm. We have successfully measured thermal pulses with a TES microcalorimeter operated with an AC bias. We present here preliminary results from a single pixel detector operated under DC and AC bias conditions

  10. Study on radioimmunoassay of Bt Cry1Ac protein

    Bt Cry1Ac protein was extracted from incubation of Bacillus thuringiensis HD-73, and cutting into more specific protein segment with high insect-resistance. High-affinity multi-colonial antibodies of Bt Cry1 Ac protein were obtained after injected it into New Zealand rabbits. By 125I labeling of Bt Cry1 Ac protein, a RIA kit was established. In this method, centrifuge for separation was not necessary due to the use of magnetic micro-particle and the specifications of the kit were found equal to those of imported ELISA. (authors)

  11. Stochastic Dynamics of DC and AC Driven Dislocation Kinks

    Vardanyan, A.; Kteyan, A.

    2013-02-01

    Dynamics of a pinned dislocation kink controlled by the acting DC and AC forces is studied analytically. The motion of the kink, described by sine-Gordon (sG) equation, is explored within the framework of McLaughlin-Scott perturbation theory. Assuming weakness of the acting AC force, the equation of motion of the dislocation kink in the pinning potential is linearized. Based on the equations derived, we study stochastic behavior of the kink, and determine the probability of its depinning. The dependencies of the depinning probability on DC and AC forces are analyzed in detail.

  12. Observation of β-delayed fission from 230Ac

    β-delayed fission for 230Ac was searched. 230Ra was produced via multinucleon transfer reaction by 60 MeV/u 18O ion irradiation of 232Th target. Thin 230Ra→230Ac sources of 108 atoms were acquired through radiochemical separations. The mica track detectors were used to record the fission events. The β-delayed fission nucleus 230Ac was identified via the observed two fission events and the measured γ-ray spectra. Its β-delayed fission probability was obtained to be (1.19 +- 0.85) x 10-8

  13. Neurinoma central do nervo acústico

    Paulo Pinto Pupo

    1950-03-01

    Full Text Available O autor apresenta o caso de uma paciente com 45 anos, com hipertensão arterial, queixando-se de tonturas e surdez progressiva à esquerda que, ao exame neurológico, apresentava síndrome protuberancial, com hemi-anestesia táctil e dolorosa à direita respeitando a face, hemiparesia direita, ataxia de tipo sensitivo nos membros da direita, paralisia facial de tipo periférico, hipoacusia, paresia de motor ocular externo à esquerda, síndrome vertiginosa e nistagmo horizontal ao olhar para a direita. À necrópsia foi encontrado um tumor na hemicalota protuberancial esquerda e foco malácico adjacente, secundário a distúrbio circulatório. O tumor, intimamente dependente das raízes intraprotuberanciais do nervo acústico, se apresentava com as características histológicas dos neurinomas. Além dessas particularidades, a lesão do feixe central da calota e conseqüente degeneração "hipertrófica" da oliva bulbar constituem outro aspecto de grande interêsse dêste caso.

  14. AC Impedance Behaviour of Black Diamond Films

    Haitao YE; Olivier GAUDIN; Richard B.JACKMAN

    2005-01-01

    The first measurement of impedance on free-standing diamond films from 0.1 Hz to 10 MHz up to 300℃ were reported. A wide range of chemical vapour deposition (CVD) materials were investigated, but here we concentrate are well fitted to a RC parallel circuit model and the equivalent resistance and capacitance for the diamond films have been estimated using the Zview curve fitting. The results show only one single semicircle response at each temperature measured. It was found that the resistance decreases from 62 MΩ at room temperature to 4 kΩ at300℃, with an activation energy around 0.51 eV. The equivalent capacitance is maintained at the level of 100 pF up to 300℃ suggesting that the diamond grain boundaries are dominating the conduction. At 400℃, the impedance at low frequencies shows a linear tail, which can be explained that the AC polarization of diamond/Au interface occurs.

  15. Dicty_cDB: FCL-AC22 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC22 (Link to dictyBase) - G03266 DDB0186811 Contig-U14995-1 FCL-...AC22P (Link to Original site) FCL-AC22F 430 FCL-AC22Z 521 FCL-AC22P 951 - - Show FCL-AC22 Library FC...L (Link to library) Clone ID FCL-AC22 (Link to dictyBase) Atlas ID - NBRP ID G03266 dictyBase ID DDB0186811 ...Link to Contig Contig-U14995-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-...AC22Q.Seq.d/ Representative seq. ID FCL-AC22P (Link to Original site) Representative DNA sequence >FCL-

  16. Dicty_cDB: FCL-AC23 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC23 (Link to dictyBase) - G01760 DDB0186002 Contig-U16043-1 FCL-...AC23P (Link to Original site) FCL-AC23F 132 FCL-AC23Z 582 FCL-AC23P 714 - - Show FCL-AC23 Library FC...L (Link to library) Clone ID FCL-AC23 (Link to dictyBase) Atlas ID - NBRP ID G01760 dictyBase ID DDB0186002 ...Link to Contig Contig-U16043-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-...AC23Q.Seq.d/ Representative seq. ID FCL-AC23P (Link to Original site) Representative DNA sequence >FCL-

  17. Absorption and Attenuation Coefficients Using the WET Labs ac-s in the Mid-Atlantic Bight: Field Measurements and Data Analysis

    Ohi, Nobuaki; Makinen, Carla P.; Mitchell, Richard; Moisan, Tiffany A.

    2008-01-01

    Ocean color algorithms are based on the parameterization of apparent optical properties as a function of inherent optical properties. WET Labs underwater absorption and attenuation meters (ac-9 and ac-s) measure both the spectral beam attenuation [c (lambda)] and absorption coefficient [a (lambda)]. The ac-s reports in a continuous range of 390-750 nm with a band pass of 4 nm, totaling approximately 83 distinct wavelengths, while the ac-9 reports at 9 wavelengths. We performed the ac-s field measurements at nine stations in the Mid-Atlantic Bight from water calibrations to data analysis. Onboard the ship, the ac-s was calibrated daily using Milli Q-water. Corrections for the in situ temperature and salinity effects on optical properties of water were applied. Corrections for incomplete recovery of the scattered light in the ac-s absorption tube were performed. The fine scale of spectral and vertical distributions of c (lambda) and a (lambda) were described from the ac-s. The significant relationships between a (674) and that of spectrophotometric analysis and chlorophyll a concentration of discrete water samples were observed.

  18. A precursor of β-delayed fission:230Ac

    2002-01-01

    The 230Ra has been produced via multinucleon transfer and dissipativefragmentation of heavy target in the 60 MeV/u 18O ion reaction with natural thorium.The radium was radiochemically separated from irradiated thorium targets. 230Acwas obtained by 230Ra β-→ 230Ac. Thin Ra sources were prepared for observing fissionfragments from β-delayed fission of 230Ac. The sources were exposed to the micafission track detectors and measured by a HPGe γ detector. The two fission eventswere obtained and could been assigned to theβ-delayed fission of 230Ac. The β-delayedfission probability of 230Ac was determined to be (1.19+0.85) × 10-8.

  19. AC susceptibility of polycrystalline (Bi-Pb 2223 superconductors

    H. Salamati

    2004-06-01

    Full Text Available   The temperature dependence of ac susceptibility of (Bi-Pb2223 polycrystalline samples was measured as a function of frequency and ac field amplitude. Analysis of the temperature dependence of the AC susceptibility near the transition temperature (Tc has been done employing Bean’s critical state model. The observed variation of intergranular critical current densities (Jc with temperature indicates that the weak links are superconductor- normal metal-superconductor (SNS type for this sample. The frequency effect on AC susceptibility was also measured. As the frequency increases, (TP shifts to higher temperatures. This effect can be interpreted in terms of flux creep. The temperature T, and field, , dependence of activation energy obtained from the Arrhenius plot for the frequency ( f and ( TP , can be described as: U(Hac,T=U0(1-T/TCHac-0.18

  20. Performance of an x-ray microcalorimeter under ac biasing

    Frequency domain multiplexing (FDM) is an attractive option for the readout of imaging arrays of microcalorimeters. Implementation of FDM requires ac biasing of the individual microcalorimeters. In this letter we present a small signal model for the behavior of a microcalorimeter under ac bias. Moreover, we have measured the behavior of the same microcalorimeter under ac (at 46 kHz) and dc bias. These experiments show that the performance of the device is very similar in terms of energy resolution, pulse shapes, and current-voltage characteristics. The measured energy resolution at 5.89 keV is 6.9 eV for ac bias and 5.5 eV for dc bias. The effective time constant in both cases is 100 μs

  1. Dc to ac converter operates efficiently at low input voltages

    1965-01-01

    Self-oscillating dc to ac converter with transistor switching to produce a square wave output is used for low and high voltage power sources. The converter has a high efficiency throughout a wide range of loads.

  2. Ferromagnetic resonance driven by an ac current: a brief review

    Excitation of ferromagnetic resonance (FMR) by an ac current has been observed in macroscopic ferromagnetic films for decades and typically relies on the ac Oersted field of the current to drive magnetic moments into precession and classical rectification of ac signals to detect the resonance. Recently, current-driven ferromagnetic resonances have attracted renewed attention with the discovery of the spin-transfer torque (STT) effect due to its potential applications in magnetic memory and microwave technologies. Here STT associated with the ac current is used to drive magnetodynamics on the nanoscale that enables FMR studies in sample volumes smaller by a factor of 1000 compared to conventional resonance techniques. In this paper, we briefly review the basics of STT-FMR technique and the results of various STT-FMR experiments.

  3. c-axis ac susceptibility in high-Tc superconductors

    We have investigated the angle and magnetic field dependence of the ac susceptibility in Bi2Sr2CaCu2O8 and YBa2Cu3O7 single crystals at low external fields. The ac field was applied perpendicular to the CuO2 planes. The first and third harmonics of the ac susceptibility exhibit remarkably sharp features when the dc field component perpendicular to the CuO2 planes passes a threshold field Hth. Hth is strongly temperature dependent, but is independent of the parallel field component. We propose a simple model which excellently explains the data. Within this model the peak structures are related to the irreversibility line. We discuss the implications of the model for the interpretation of the ac susceptibility. copyright 1996 The American Physical Society

  4. Fabrication of alumina films with laminated structures by ac anodization

    Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50–200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials. (paper)

  5. American Community Survey (ACS) 5-Year Estimates for Coastal Geographies

    National Oceanic and Atmospheric Administration, Department of Commerce — The American Community Survey (ACS) is an ongoing statistical survey that samples a small percentage of the population every year. These data have been apportioned...

  6. Muc5ac mucin expression during rat skin development

    V. Ferretti; Á. Segal-Eiras; Barbeito, C.G.; Croce, M. V.

    2015-01-01

    Some mucin genes have been detected during human embryonic and fetal organ development; however, little is known about mucin expression in epidermal development, neither in humans nor in other species. The present research was developed to explore Muc5ac skin expression during prenatal and postnatal rat development. Immunohistochemistry (IHC), Western blotting (WB) and RT-PCR were employed. By IHC, Muc5ac protein was found early in embryonic epidermis from day 13 of gestation until seven days...

  7. Dynamics of a nanowire superlattice in an ac electric field

    Zhang, Aizhen; Voon, L. C. Lew Yan; M. Willatzen

    2005-01-01

    With a one-band envelope function theory, we investigate the dynamics of a finite nanowire superlattice driven by an ac electric field by solving numerically the time-dependent Schroedinger equation. We find that for an ac electric field resonant with two energy levels located in two different minibands, the coherent dynamics in nanowire superlattices is much more complex as compared to the standard two-level description. Depending on the energy levels involved in the transitions, the coheren...

  8. Fractal AC circuits and propagating waves on fractals

    Akkermans, Eric; Dunne, Gerald; Rogers, Luke G; Teplyaev, Alexander

    2015-01-01

    We extend Feynman's analysis of the infinite ladder AC circuit to fractal AC circuits. We show that the characteristic impedances can have positive real part even though all the individual impedances inside the circuit are purely imaginary. This provides a physical setting for analyzing wave propagation of signals on fractals, by analogy with the Telegrapher's Equation, and generalizes the real resistance metric on a fractal, which provides a measure of distance on a fractal, to complex impedances.

  9. Autonomous Operation of Hybrid Microgrid With AC and DC Subgrids

    Chiang Loh, Poh; Li, Ding; Kang Chai, Yi;

    2013-01-01

    This paper investigates on power-sharing issues of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac subgrids interconnected by power electronic interfaces. The main challenge here is to manage power flows among all...... converters. Suitable control and normalization schemes are now developed for controlling them with the overall hybrid microgrid performance already verified in simulation and experiment....

  10. AC resistivity of d-wave ceramic superconductors

    Li, Mai Suan; Dominguez, Daniel

    2000-01-01

    We model d-wave ceramic superconductors with a three-dimensional lattice of randomly distributed $\\pi$ Josephson junctions with finite self-inductance. The linear and nonlinear ac resistivity of the d-wave ceramic superconductors is obtained as function of temperature by solving the corresponding Langevin dynamical equations. We find that the linear ac resistivity remains finite at the temperature $T_p$ where the third harmonics of resistivity has a peak. The current amplitude dependence of t...

  11. Scaling and universality of ac conduction in disordered solids

    Schrøder, Thomas; Dyre, Jeppe

    2000-01-01

    Recent scaling results for the ac conductivity of ionic glasses by Roling et al. [Phys. Rev. Lett. 78, 2160 (1997)] and Sidebottom [Phys. Rev. Lett. 82, 3653 (1999)] are discussed. We prove that Sidebottom's version of scaling is completely general. A new approximation to the universal ac conduct...... conductivity arising in the extreme disorder limit of the symmetric hopping model, the "diffusion cluster approximation," is presented and compared to computer simulations and experiments....

  12. ISTTOK upgrade towards AC and remote operation

    ISTTOK has performed one of the earliest experiments of AC tokamak operation showing that long discharges could be produced merely with inductive current drive. However, due to the design of the machine, the data acquisition system and the power supplies, a limit of 250 ms (six times the nominal forward shot duration) is currently imposed.In this paper the relevant constrains to attain current operation up to the limit of the stable toroidal magnetic field (3s) are discussed and the work being carried out to achieve this goal is presented.The conditions that shall be accomplished are: (i) removing the power deposited on the limiters; (ii) density control through gas puffing and monitoring the recycling from the walls; (iii) assessment of the free magnetic flux available on the iron core (Wmax=0.2 Vs); (iv) reformulation of the data acquisition system towards an event driven philosophy maintaining the actual distributed architecture but allowing a real-time control; (v) active control of the equilibrium magnetic fields implementing a digital plasma position estimator and actuator through new power supplies for the poloidal magnetic fields. As a new high level software was needed to implement all this features, the ISTTOK data acquisition system and control has been totally redesigned in JAVA/SQL database technology and time stamps events were adopted to catalogue the data. This software has been design keeping in mind the needs for remote participation and operation of the machine. Therefore, a cooperative environment has been implemented where several persons can be connected together to the platform, programming their own devices and exchanging knowledge or opinions through an embedded chat

  13. ISTTOK upgrade towards AC and remote operation

    Fernandes, H.; Silva, C.; Carvalho, B.; Sousa, J.; Valcárcel, D.; Neto, A.; Fortunato, J.; Carvalho, I.; Varandas, C. A. F.

    2006-12-01

    ISTTOK has performed one of the earliest experiments of AC tokamak operation showing that long discharges could be produced merely with inductive current drive. However, due to the design of the machine, the data acquisition system and the power supplies, a limit of 250 ms (six times the nominal forward shot duration) is currently imposed. In this paper the relevant constrains to attain current operation up to the limit of the stable toroidal magnetic field (3s) are discussed and the work being carried out to achieve this goal is presented. The conditions that shall be accomplished are: (i) removing the power deposited on the limiters; (ii) density control through gas puffing and monitoring the recycling from the walls; (iii) assessment of the free magnetic flux available on the iron core (Wmax=0.2 Vs); (iv) reformulation of the data acquisition system towards an event driven philosophy maintaining the actual distributed architecture but allowing a real-time control; (v) active control of the equilibrium magnetic fields implementing a digital plasma position estimator and actuator through new power supplies for the poloidal magnetic fields. As a new high level software was needed to implement all this features, the ISTTOK data acquisition system and control has been totally redesigned in JAVA/SQL database technology and time stamps events were adopted to catalogue the data. This software has been design keeping in mind the needs for remote participation and operation of the machine. Therefore, a cooperative environment has been implemented where several persons can be connected together to the platform, programming their own devices and exchanging knowledge or opinions through an embedded chat.

  14. Simulation of the Relaxation Potential Profile of an ac-dc-ac Test

    Kerry N. Allahar

    2014-01-01

    Full Text Available The relaxation period of the accelerated ac-dc-ac test for coatings is associated with the transient electrochemistry that occurs when the immersed coated system is allowed to return to a stable open-circuit condition after being subjected to a cathodic potential. A mathematical model of the transient electrochemistry that occurs during this relaxation period is presented for coated aluminum. Expressions for the corrosion potential and corrosion current as functions of the local pH at the metal-coating interface were developed using reported experimental results. These expressions enabled the simulation of the transient electrochemistry under the constraint of balanced anodic and cathodic current densities. Regression of the transient relaxation potential profiles to exponential decay functions provided time-constant characterization of the profiles. Simulated results are presented that demonstrate the influences of the coating's porosity and thickness, the applied dc potential and the metal-coating interface condition on the time-constants associated with the relaxation profile. Interpretation of experimentally reported relaxation potential profiles supported the analysis of the simulated results.

  15. Diagnostics of the Fermilab Tevatron using an AC dipole

    Miyamoto, Ryoichi; /Texas U.

    2008-08-01

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f {approx} 20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  16. Controlo de um conversor AC-DC-AC para turbinas eólicas baseadas no PMSG

    Bulhosa, João Paulo Rodrigues

    2009-01-01

    A dissertação teve como objectivo o estudo e implementação do controlo de um conversor AC-DC-AC, constituído por um conversor DC/DC elevador e um inversor de tensão monofásico, para efectuar a ligação à rede de turbinas eólicas baseadas no gerador síncrono de ímanes permanentes. O controlo global do conversor AC-DC-AC seguiu uma estratégia na qual o controlo do conversor elevador e do inversor de tensão monofásico é implementado de modo independente. O primeiro visa maximizar a potência ex...

  17. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach it is not required to do any measurements, thus making it more reliable. Initial testing made on the prototype prove the feasibility of the approach. (au)

  18. Monoclonal antibodies AC-43 and AC-29 disrupt Plasmodium vivax development in the Indian malaria vector Anopheles culicifacies (Diptera: culicidae)

    Manoj Chugh; B R Gulati; S K Gakhar

    2010-03-01

    A repertoire of monoclonal antibodies (mAbs) was generated against the midgut proteins of Anopheles culicifacies mosquitoes. The mAbs AC-43 and AC-29 significantly inhibited Plasmodium vivax development inside the mosquito midgut. The number of oocysts that developed was reduced by 78.6% when mosquitoes ingested a combination of these two mAbs along with the blood meal. AC-43 mAb binds to the epitope common in 97, 80 and 43 kDa polypeptides from the midgut protein extract, as indicated by western blot analysis. Similarly, the mAb AC-29 recognized 52, 44, 40 and 29 kDa polypeptides. These female midgut-specific polypeptides are shared between An. culicifacies and An. stephensi, two major vectors of malaria in India. Deglycosylation assays revealed that -linked carbohydrates are the major components in epitopes corresponding to AC-43 and AC-29. Gold particle labelling revealed that both these mAbs preferentially bind to glycoproteins at the apical microvilli and the microvillus-associated network present inside transverse sections of the gut epithelium. These regions are particularly known to have receptors for ookinetes, which enable them to cross this epithelial barrier and provide them with certain necessary chemicals or components for further development into oocysts. Therefore, these glycoproteins appear to be potential candidates for a vectordirected transmission-blocking vaccine (TBV).

  19. Temas de Física para Ingeniería: Acústica

    Beléndez Vázquez, Augusto

    1992-01-01

    Acústica, fluidos y termodinámica: "Acústica". Ondas sonoras, propagación. Sonidos puros, sonidos complejos y ruidos. Velocidad de propagación del sonido. Intensidad del sonido y potencia acústica. Impedancia acústica y transmisión del sonido. Medición del campo acústico: niveles. Audición. Interferencia de ondas sonoras y pulsaciones. Tubos sonoros. Efecto Doppler.

  20. Analysis of AC loss in superconducting power devices calculated from short sample data

    Rabbers, J.J.; Haken, ten, Bennie; Kate, ten, F.J.W.

    2003-01-01

    A method to calculate the AC loss of superconducting power devices from the measured AC loss of a short sample is developed. In coils and cables the magnetic field varies spatially. The position dependent field vector is calculated assuming a homogeneous current distribution. From this field profile and the transport current, the local AC loss is calculated. Integration over the conductor length yields the AC loss of the device. The total AC loss of the device is split up in different compone...

  1. Behaviour analysis of AC-600 passive safety systems

    Southwest Center of Reactor Engineering Research and Design has finished the first step conceptual design of 600 mwe advanced PWR (AC-600). The main research emphases of AC-600 conceptual design include the advanced reactor core, the passive safety systems and the simplification. The passive safety systems of AC-600 consist of two reactor make up water tanks, two accumulators, two emergency feedwater tanks, two emergency natural draft air condensers, a containment water jacket and an enhanced primary cycle natural circulation flow system. 25% of the rated reactor power can be removed by the natural circulation cooling. The full pressure reactor make up water tanks are able to provide enough borated water which would be injected into the reactor coolant system during small LOCA. The coolant natural circulations can be established in the primary system and the passive secondary emergency feedwater system, removing residual heat from the reactor core to the atmosphere when station blackout occurs. It is indicated from analysis that the containment diameter of AC-600 is about 35 m. The large tanks and the large vertical distances between the tanks and reactor core are the main reason of using the big containment. It is also indicated from analysis that the low head safety injection pumps are required in AC-600 design to assure the recirculation system operation when large LOCA occurs. The reliability of AC-600 engineered safety systems is increased because the function of the passive safety systems is conducted through the immutable natural laws. The paper discusses the natural circulation ability and safety behavior of the passive safety systems during LOCA or station blackout for AC-600. The passive limits to excess reactivity and thermal hydraulic transients are also preliminarily discussed. Figs and tabs

  2. An AC/AC Direct Power Conversion Topology Having Multiple Power Grid Connections with Adjustable Loading

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    these fraction power will be a necessary feature on a deregulated energy market. This paper presents a new topology of a power converter based on the Direct Power Conversion concept, which is able to connect to multiple grids and provide complete decoupling between without circulating power between the......Normally, a power converter has one supply port to connect to the power grid and one or multiple output ports to connect to AC loads that require variable voltage and variable frequency. As the trend on the energy market is towards deregulation, new converter topologies are needed to allow...... to minimize the overall energy cost or in case of special applications, to improve the system redundancy. Also, having a generator that can simultaneously feed fractions of its power into multiple grids which are not coupled (different voltage, frequency, displacement angle) and continuously adjust...

  3. Isolation of MA-ACS Gene Family and Expression Study of MA-ACS1 Gene in Musa acuminata Cultivar Pisang Ambon Lumut

    LISTYA UTAMI KARMAWAN

    2009-03-01

    Full Text Available Musa acuminata cultivar pisang ambon lumut is a native climacteric fruit from Indonesia. Climacteric fruit ripening process is triggered by the gaseous plant hormone ethylene. The rate limiting enzyme involved in ethylene biosynthesis is ACC synthase (ACS which is encoded by ACS gene family. The objective of this study is to identify MA-ACS gene family in M. acuminata cultivar pisang ambon lumut and to study the MA-ACS1 gene expression. The result showed that there were nine M. acuminata ACS gene family members called MA-ACS1–9. Two of them (MA-ACS1 and MA-ACS2 were assessed using reverse transcriptase PCR (RT-PCR for gene expression study and it was only MA-ACS1 correlated with fruit ripening. The MA-ACS1 gene fragment has been successfully isolated and characterized and it has three introns, four exons, and one stop codon. It also shows highest homology with MACS1 gene from M. acuminata cultivar Hsian Jien Chiao (GenBank accession number AF056164. Expression analysis of MA-ACS1 using quantitative PCR (qPCR showed that MA-ACS1 gene expression increased significantly in the third day, reached maximum at the fifth day, and then decreased in the seventh day after harvesting. The qPCR expression analysis result correlated with the result of physical analysis during fruit ripening.

  4. Modelling ac ripple currents in HTS coated conductors

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  5. AC Zeeman potentials for atom chip-based ultracold atoms

    Fancher, Charles; Pyle, Andrew; Ziltz, Austin; Aubin, Seth

    2015-05-01

    We present experimental and theoretical progress on using the AC Zeeman force produced by microwave magnetic near-fields from an atom chip to manipulate and eventually trap ultracold atoms. These AC Zeeman potentials are inherently spin-dependent and can be used to apply qualitatively different potentials to different spin states simultaneously. Furthermore, AC Zeeman traps are compatible with the large DC magnetic fields necessary for accessing Feshbach resonances. Applications include spin-dependent trapped atom interferometry and experiments in 1D many-body physics. Initial experiments and results are geared towards observing the bipolar detuning-dependent nature of the AC Zeeman force at 6.8 GHz with ultracold 87Rb atoms trapped in the vicinity of an atom chip. Experimental work is also underway towards working with potassium isotopes at frequencies of 1 GHz and below. Theoretical work is focused on atom chip designs for AC Zeeman traps produced by magnetic near-fields, while also incorporating the effect of the related electric near-fields. Electromagnetic simulations of atom chip circuits are used for mapping microwave propagation in on-chip transmission line structures, accounting for the skin effect, and guiding impedance matching.

  6. Aragonite coating solutions (ACS) based on artificial seawater

    Tas, A. Cuneyt

    2015-03-01

    Aragonite (CaCO3, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca10(PO4)6(OH)2), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry.

  7. AC losses in circular arrangements of parallel superconducting tapes

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Däumling, Manfred; Olsen, Søren Krüger; Tønnesen, Ole

    The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two arrangem......The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two...... arrangements, scale with the number of tapes and hence appear to be independent of the diameter.However, the AC loss per tape (for a given current per tape) appears to decrease with increasing diameter of the circular arrangement. Compared to a model for the AC loss in a continuous superconducting layer...... (Monoblock model) the measured values are about half an order of magnitude higher than expected for the small diameter arrangement. When compared to the AC loss calculated for N individual superconducting tapes using a well known model ( Norris elliptical) the difference is slightly smaller....

  8. AC losses in circular arrangements of parallel superconducting tapes

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Däumling, Manfred;

    1998-01-01

    The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two arrangem......The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two...... arrangements, scale with the number of tapes and hence appear to be independent of the diameter.However, the AC loss per tape (for a given current per tape) appears to decrease with increasing diameter of the circular arrangement. Compared to a model for the AC loss in a continuous superconducting layer...... (Monoblock model) the measured values are about half an order of magnitude higher than expected for the small diameter arrangement. When compared to the AC loss calculated for N individual superconducting tapes using a well known model ( Norris elliptical) the difference is slightly smaller....

  9. System and method for determining stator winding resistance in an AC motor using motor drives

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  10. On the Application of TLS Techniques to AC Electrical Drives

    M. Cirrincione

    2005-03-01

    Full Text Available This paper deals with the application of a new neuron, the TLS EXIN neuron, to AC induction motor drives. In particular, it addresses two important subjects of AC induction motor drives: the on-line estimation of the electrical parameters of the machine and the speed estimation in sensorless drives. On this basis, this work summarizes the parameter estimation and sensorless techniques already developed by the authors over these last few years, all based on the TLS EXIN. With regard to sensorless, two techniques are proposed: one based on the MRAS and the other based on the full-order Luenberger observer. The work show some of the most significant results obtained by the authors in these fields and stresses the important potentiality of this new neural technique in AC induction machine drives.

  11. Voltage drop of the SACLA AC power supply

    We installed the AC power supply of SACLA by construction. The AC power supply is connected to an inverter power supply. Because of charge and discharge to a modulator, it is necessary to supply pulsatile electricity. The total consumption electricity of approximately 70 modulators extends to 5,000kVA. A severe electric current flows, and repeats relaxing. The influence of the voltage change by the impedance of the distribution system grows big, too. In SACLA, we designed the voltage regulation at less than 10%. SACLA succeeded in laser oscillation in this June. Because we was able to put it in the predetermined voltage regulation in the machine AC power supply, I report the details. (author)

  12. Neural network based PWM AC chopper fed induction motor drive

    Venkatesan Jamuna

    2009-01-01

    Full Text Available In this paper, a new Simulink model for a neural network controlled PWM AC chopper fed single phase induction motor is proposed. Closed loop speed control is achieved using a neural network controller. To maintain a constant fluid flow with a variation in pressure head, drives like fan and pump are operated with closed loop speed control. The need to improve the quality and reliability of the drive circuit has increased because of the growing demand for improving the performance of motor drives. With the increased availability of MOSFET's and IGBT's, PWM converters can be used efficiently in low and medium power applications. From the simulation studies, it is seen that the PWM AC chopper has a better harmonic spectrum and lesser copper loss than the Phase controlled AC chopper. It is observed that the drive system with the proposed model produces better dynamic performance, reduced overshoot and fast transient response. .

  13. Microdischarges of AC-coupled silicon strip sensors

    Microdischarge at the edges of strips in AC-coupled silicon strip sensors has been investigated. A steep increase in the leakage current (breakdown) and a sudden onset of burst noise were observed at a low reverse-bias voltage when the bias potential was across the AC-coupling capacitor. This can be explained by the occurrence of microdischarges along the edges of strips. These discharges have been confirmed by observing IR light emission. A calculation of the field strength at the strip edge suggests that a fringe field of the external electrode generates the microdischarge at the strip edge when the bias voltage is 50-80 V. This is consistent with our observations. We discuss a design for AC-coupled sensors that eliminates this discharge problem. (orig.)

  14. Reliability of emergency ac power systems at nuclear power plants

    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project

  15. Analysis of ac Surface Photovoltages in Accumulation Region

    Munakata, Chusuke

    1988-05-01

    Equations for ac surface photovoltages (SPVs) excited with a chopped photon beam (PB) in the accumulation region are proposed for such semiconductors as silicon and germanium. Following the previously reported half-sided junction model for the depleted or inverted region, equations for photocurrent density and surface impedance per unit area have been newly deduced. When the surface potential is highly negative in p-type semiconductors, the maximum ac SPV in the accumulation region is limited by the conductance due to majority carrier diffusion flow. This is compared with the strong inversion region, where the mathematically maximum SPV depends upon the minority carrier diffusion flow. The voltage ratio between the two maximum ac SPVs is the same as that previously reported using the different models for dc SPVs excited with a continuous PB.

  16. Experiments on Corona Discharge Under AC and DC Composite Voltage

    ZHU Zhengyi; LI Ruihai; WANG Guoli; CHEN Can; JIA Zhidong; GUAN Zhicheng

    2012-01-01

    Converter transformers are one of the most important electrical apparatuses in the ultra high voltage(UHV) DC transmission systems.The valve side and the low voltage(LV) bushing are stressed by long-term AC and DC composite voltage leading to significant partial discharge(PD) and posing great danger to the insulation system.In this paper AC and DC composite voltage is applied on a metal needle-plate model to produce PD signal sequences,and then the pulse waveshape and frequency spectrum are analyzed and compared with PD signals under conventional AC or DC voltage.In the end,the phase-resolved distribution is analyzed to depict the new characteristics of PD under this composite voltage.

  17. Encapsulation of α-Particle–Emitting 225Ac3+ Ions Within Carbon Nanotubes

    Matson, Michael L.; Villa, Carlos H.; Ananta, Jeyarama S.; Law, Justin J.; Scheinberg, David A.; Wilson, Lon J.

    2016-01-01

    225Ac3+ is a generator of α-particle–emitting radionuclides with 4 net α-particle decays that can be used therapeutically. Targeting 225Ac3+ by use of ligands conjugated to traditional bifunctional chelates limits the amount of 225Ac3+ that can be delivered. Ultrashort, single-walled carbon nanotubes (US-tubes), previously demonstrated as sequestering agents of trivalent lanthanide ions and small molecules, also successfully incorporate 225Ac3+. Methods Aqueous loading of both 225Ac3+ ions and Gd3+ ions via bath sonication was used to construct 225Ac@gadonanotubes (225Ac@GNTs). The 225Ac@GNTs were subsequently challenged with heat, time, and human serum. Results US-tubes internally loaded with both 225Ac3+ ions and Gd3+ ions show 2 distinct populations of 225Ac3+ ions: one rapidly lost in human serum and one that remains bound to the US-tubes despite additional challenge with heat, time, and serum. The presence of the latter population depended on cosequestration of Gd3+ and 225Ac3+ ions. Conclusion US-tubes successfully sequester 225Ac3+ ions in the presence of Gd3+ ions and retain them after a human serum challenge, rendering 225Ac@GNTs candidates for radioimmunotherapy for delivery of 225Ac3+ ions at higher concentrations than is currently possible for traditional ligand carriers. PMID:25931476

  18. AC power losses in Bi-2223/Ag HTS tapes

    Full text: We report measurements at 77 K of the transport ac losses of Bi-2223/Ag composite tapes. The investigated tapes vary from single filament to multifilament construction and include both conventional tapes and other conductor shapes with twisted filaments. The self-field ac losses were determined at 77 K and 60 Hz as a function of ac current amplitude (0 - 100 A). We observe different behaviour among tapes depending on their quality and strain history. For 'good' virgin tapes the experimental data are well described by the Norris equations for the dependence of power loss P on the amplitude Im of the transport current. The data of good monofilament tapes are fitted to the Norris equation P ∼ Imn for an elliptical cross section (ie. n = 3) and the data of good multifilament tapes are fitted to the Norris equation for a rectangular strip (ie. n = 4). Many specimens, however, show a range of behaviour with lower values of n. Based on our work on the effect of strain on the dc transport properties of tapes, we carried out detailed investigations of the effect of controlled applied bend strain on the ac loss. Our results show that irreversible damage to superconducting filaments (ie. cracks) cause the ac loss to rise and n to decrease with increasing strain. In addition, applied strains much greater than the irreversible strain limit cause the ac loss to increase by several orders of magnitude and become ohmic in character with n = 2. Theoretical work is in progress to model the observed behaviour

  19. Aligned Immobilization of Proteins Using AC Electric Fields.

    Laux, Eva-Maria; Knigge, Xenia; Bier, Frank F; Wenger, Christian; Hölzel, Ralph

    2016-03-01

    Protein molecules are aligned and immobilized from solution by AC electric fields. In a single-step experiment, the enhanced green fluorescent proteins are immobilized on the surface as well as at the edges of planar nanoelectrodes. Alignment is found to follow the molecules' geometrical shape with their longitudinal axes parallel to the electric field. Simultaneous dielectrophoretic attraction and AC electroosmotic flow are identified as the dominant forces causing protein movement and alignment. Molecular orientation is determined by fluorescence microscopy based on polarized excitation of the proteins' chromophores. The chromophores' orientation with respect to the whole molecule supports X-ray crystal data. PMID:26779699

  20. AC transport in graphene-based Fabry-Perot devices

    Rocha, Claudia G; Torres, Luis E. F. Foa; Cuniberti, Gianaurelio

    2009-01-01

    We report on a theoretical study of the effects of time-dependent fields on electronic transport through graphene nanoribbon devices. The Fabry-P\\'{e}rot interference pattern is modified by an ac gating in a way that depends strongly on the shape of the graphene edges. While for armchair edges the patterns are found to be regular and can be controlled very efficiently by tuning the ac field, samples with zigzag edges exhibit a much more complex interference pattern due to their peculiar elect...

  1. A.C. losses in current-carrying superconductors

    The feasibility of superconductors for alternating current use depends on successful reduction of losses. Moreover, the demand for large field amplitudes is a stimulation for investigating the nature of a.c. losses (e.g. in the set of poloidal coils in a TOKAMAK). In this thesis, measurements are performed at a.c. superconductivity. Attention is given to various external field conditions as well as to self-field instability. Measurements are performed on different types of wires. A type of wire is searched for with both low losses and a good stabilization under self-field conditions. (G.J.P.)

  2. AC Loss Analysis on the Superconducting Coupling Magnet in MICE

    Wu, Hong; Wang, Li; Green, Michael; Li, LanKai; Xu, FengYu; Liu, XiaoKun; Jia, LinXinag

    2008-07-08

    A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC losses on the temperature distribution within the cold mass during charging and rapid discharging process is analyzed also. The analysis result will be further confirmed by the experiment of the prototype solenoid for coupling solenoid, which will be designed, fabricated and tested at ICST.

  3. Comportamiento acústico de espacios cubiertos con estructuras textiles

    Maya Simoes, Flavio

    2000-01-01

    En el presente trabajo estudiamos el comportamiento acústico de espacios cubiertos con textiles. Presentamos una reseña histórica de usos de textiles en la arquitectura, de la prehistoria hasta hoy. Realizamos una búsqueda bibliográfica y presentamos los resultados encontrados. Presentamos la metodología actual de análisis acústico que se utiliza en ensayos de laboratorio, simulaciones y mediciones. Estudiamos la absorción sonora de los materiales de las cubiertas textiles, en ensayos de labo...

  4. Interplay between electron overheating and ac Josephson effect

    De Cecco, A.; Le Calvez, K.; Sacépé, B.; Winkelmann, C. B.; Courtois, H.

    2016-05-01

    We study the response of high-critical-current proximity Josephson junctions to a microwave excitation. Electron overheating in such devices is known to create hysteretic dc voltage-current characteristics. Here we demonstrate that it also strongly influences the ac response. The interplay of electron overheating and ac Josephson dynamics is revealed by the evolution of the Shapiro steps with the microwave drive amplitude. Extending the resistively shunted Josephson junction model by including a thermal balance for the electronic bath coupled to phonons, a strong electron overheating is obtained.

  5. EHV AC undergrounding electrical power performance and planning

    Benato, Roberto

    2010-01-01

    EHV AC Undergrounding Electrical Power discusses methods of analysis for cable performance and for the behaviour of cable, mixed and overhead lines. The authors discuss the undergrounding of electrical power and develop procedures based on the standard equations of transmission lines. They also provide technical and economical comparisons of a variety of cables and analysis methods, in order to examine the performance of AC power transmission systems. A range of topics are covered, including: energization and de-energization phenomena of transmission lines; power quality; and cable safety cons

  6. Geodetska dela pri izgradnji AC priključka Naklo

    Pavc, Iztok

    2015-01-01

    V diplomski nalogi sem predstavil geodetska dela pri izgradnji AC priključka Naklo. Opisana so dela pred, med in po izgradnji objekta. V prvem poglavju sem predstavil smernice in načrte nove ureditve priključka na avtocesto ter obseg gradnje AC priključka Naklo. Nadaljeval sem z geodetskimi deli pred gradnjo, ki so potrebni za pripravo dobrega izhodišča za nadaljnja delo med gradnjo. Opisani so vsi postopki, ki so bili opravljeni pred pripravo projekta za gradbeno dovoljenje (PGD) in tudi pre...

  7. Dynamic conductivity of ac-dc-driven graphene superlattice

    Kukhar', E. I.; Kryuchkov, S. V.; Ionkina, E. S.

    2016-06-01

    The dynamic conductivity of graphene superlattice in the presence of ac electric field and dc electric field with longitudinal and transversal components with respect to superlattice axis was calculated. In the case of strong transversal component of dc field conductivity of graphene superlattice was shown to be such as if the electrons had got the effective mass. In the case of weak transversal component of dc field conductivity was shown to change its sign if the frequency of ac field was an integer multiple of half of Bloch frequency.

  8. Development of an AC Module System: Final Technical Report

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become

  9. Stretched exponential relaxation and ac universality in disordered dielectrics

    Milovanov, Alexander V.; Rypdal, Kristoffer; Juul Rasmussen, Jens

    2007-01-01

    This paper is concerned with the connection between the properties of dielectric relaxation and alternating-current (ac) conduction in disordered dielectrics. The discussion is divided between the classical linear-response theory and a self-consistent dynamical modeling. The key issues are...... stretched exponential character of dielectric relaxation, power-law power spectral density, and anomalous dependence of ac conduction coefficient on frequency. We propose a self-consistent model of dielectric relaxation in which the relaxations are described by a stretched exponential decay function...

  10. L’acétaminophène chez les enfants

    Goldman, Ran D.

    2013-01-01

    Résumé Question Je suggère fréquemment aux parents d’utiliser de l’acétaminophène comme traitement de la fièvre et de la douleur pour leurs enfants. J’ai récemment reçu un enfant à mon cabinet qui s’est présenté avec une éruption cutanée sous forme de lésions en cibles une journée après avoir pris de l’acétaminophène. L’éruption s’est résorbée 3 jours après qu’on ait arrêté l’administration d’acétaminophène. L’acétaminophène comporte-t-elle des risques d’événements indésirables comme celui-ci? Réponse Comme les autres médicaments ou substances actives, les préparations d’acétaminophène pourraient poser des risques d’événements indésirables. Au cours des dernières années, on a procédé à une investigation concernant une association potentielle entre l’acétaminophène et l’asthme et la Food and Drug Administration des États-Unis a récemment publié un avertissement à propos de réactions cutanées éventuelles, graves mais rares, associées à l’acétaminophène. Même si l’acétaminophène est principalement un médicament sûr, les professionnels de la santé devraient être alertes et informer les parents à propos de la possibilité d’événements indésirables rares mais sévères.

  11. Programmable Power Supply for AC Switching Magnet of Proton Accelerator

    Jeong, Seong-Hun; Kang Heung Sik; Lee, Chi-Hwan; Lee, Hong-Gi; Park, Ki-Hyeon; Ryu, Chun-Kil; Sik Han, Hong; Suck Suh, Hyung

    2005-01-01

    The 100-MeV PEFP proton linac has two proton beam extraction lines for user' experiment. Each extraction line has 5 beamlines and has 5 Hz operating frequency. An AC switching magnet is used to distribute the proton beam to the 5 beamlines, An AC switching magnet is powered by PWM-controlled bipolar switching-mode converters. This converter is designed to operate at ±350A, 5 Hz programmable step output. The power supply is employed IGBT module and has controlled by a DSP (Digital Signal Process). This paper describes the design and test results of the power supply.

  12. Dicty_cDB: FCL-AC27 [Dicty_cDB

    Full Text Available GGSILASLSTFQQMWISKEEYDESGPSIVHRKCF*tnkqktsdesashkylc kiyi**iliflfilfsc*slsdfpnikkkkkkkk Homology vs CSM-cDNA Score E Sequences pr... http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC27Q.Seq.d/ Representativ...e seq. ID FCL-AC27Z (Link to Original site) Representative DNA sequence >FCL-AC27 (FCL-AC27Q) /CSM/FCL/FCL-A...VDIRKDLYGNVVLSGGTTMFPGIADRMNKELTALAPSTMKIKIIAPP ERKYSVWIGGSILASLSTFQQMWISKEEYDESGPSIVHRKCF*tnkqktsdesas.../CSM/SF/SFJ3-A/SFJ302Q.Seq.d/ 1045 0.0 own update 2004.12.25 Homology vs DNA Score E Sequences producing sig

  13. Dicty_cDB: FCL-AC10 [Dicty_cDB

    Full Text Available http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC10Q.Seq.d/ Representativ...e seq. ID FCL-AC10Z (Link to Original site) Representative DNA sequence >FCL-AC10 (FCL-AC10Q) /CSM/FCL/FCL-A...LTALAPSTMKIKIIAPP ERKYSVWIGGSILASLSTFQQMWISKEEYDESGPSIVHRKCF*tiktsdesashtnkyi* my...GNVVLSGGTTMFPGIADRMNKELTALAPSTMKIKIIAPP ERKYSVWIGGSILASLSTFQQMWISKEEYDESGPSIVHRKCF*tiktsdesashtnkyi* mynnnki....00 m_ : 1.00 40.0 %: nuclear 36.0 %: cytoplasmic 12.0 %: cytoskeletal 8.0 %: mitochondrial 4.0 %: peroxisomal >> pre

  14. Impacts on Power Factor of AC Voltage Controllers Under Non-Sinusoidal Conditions

    Mukhtiar Ahmed Mahar

    2012-04-01

    Full Text Available AC-AC conversion is obtained with the help of Cyclo-converters, DC Link converters and AC Voltage Controllers. AC voltage controllers are also referred to as voltage regulators. Main issue concerned to these converters is that they generate harmonics due to periodic variable structure system. The generated harmonics create disturbances and degrade the performance of converter. The power factor of supply side is affected due to these harmonics. This paper focuses on source side power factor of ac voltage controllers under nonsinusoidal conditions. In order to observe the power factor, measurement tool of power factor and simulation model of ac voltage controller is also developed in MATLAB software.

  15. Two very long chain fatty acid acyl-CoA synthetase genes, acs-20 and acs-22, have roles in the cuticle surface barrier in Caenorhabditis elegans.

    Eriko Kage-Nakadai

    Full Text Available In multicellular organisms, the surface barrier is essential for maintaining the internal environment. In mammals, the barrier is the stratum corneum. Fatty acid transport protein 4 (FATP4 is a key factor involved in forming the stratum corneum barrier. Mice lacking Fatp4 display early neonatal lethality with features such as tight, thick, and shiny skin, and a defective skin barrier. These symptoms are strikingly similar to those of a human skin disease called restrictive dermopathy. FATP4 is a member of the FATP family that possesses acyl-CoA synthetase activity for very long chain fatty acids. How Fatp4 contributes to skin barrier function, however, remains to be elucidated. In the present study, we characterized two Caenorhabditis elegans genes, acs-20 and acs-22, that are homologous to mammalian FATPs. Animals with mutant acs-20 exhibited defects in the cuticle barrier, which normally prevents the penetration of small molecules. acs-20 mutant animals also exhibited abnormalities in the cuticle structure, but not in epidermal cell fate or cell integrity. The acs-22 mutants rarely showed a barrier defect, whereas acs-20;acs-22 double mutants had severely disrupted barrier function. Moreover, the barrier defects of acs-20 and acs-20;acs-22 mutants were rescued by acs-20, acs-22, or human Fatp4 transgenes. We further demonstrated that the incorporation of exogenous very long chain fatty acids into sphingomyelin was reduced in acs-20 and acs-22 mutants. These findings indicate that C. elegans Fatp4 homologue(s have a crucial role in the surface barrier function and this model might be useful for studying the fundamental molecular mechanisms underlying human skin barrier and relevant diseases.

  16. Effect of combining a DC bias current with an AC transport current on AC losses in a High Temperature Superconductor

    Dolez, Patricia; Ligneris, Benoit des; Aubin, Marcel; Zhu, When; Cave, Julian

    1998-01-01

    Creating complex flux configurations by superposing a dc current or magnetic field onto the ac current in a type II superconducting tape should lead to a variety of peculiar behaviors. An example is the appearance of the Clem valley, a minimum in the ac losses as a function of the dc bias amplitude, which has been theoretically studied by LeBlanc et al., in the continuation of Clem's calculations. These situations have been investigated by applying a dc current to a silver-gold sheathed Bi-22...

  17. HIGH-FREQUENCY QUASI-SINGLE-STAGE (QSS) ISOLATED AC-DC AND DC-AC POWER CONVERSION

    Wang, Kunrong

    1998-01-01

    The generic concept of quasi-single-stage (QSS) power conversion topology for ac-dc rectification and dc-ac inversion is proposed. The topology is reached by direct cascading and synchronized switching of two variety of buck or two variety of boost switching networks. The family of QSS power converters feature single-stage power processing without a dc-link low-pass filter, a unidirectional pulsating dc-link voltage, soft-switching capability with minimal extra commutation circuitry, simple...

  18. Context based computational analysis and characterization of ARS consensus sequences (ACS) of Saccharomyces cerevisiae genome.

    Singh, Vinod Kumar; Krishnamachari, Annangarachari

    2016-09-01

    Genome-wide experimental studies in Saccharomyces cerevisiae reveal that autonomous replicating sequence (ARS) requires an essential consensus sequence (ACS) for replication activity. Computational studies identified thousands of ACS like patterns in the genome. However, only a few hundreds of these sites act as replicating sites and the rest are considered as dormant or evolving sites. In a bid to understand the sequence makeup of replication sites, a content and context-based analysis was performed on a set of replicating ACS sequences that binds to origin-recognition complex (ORC) denoted as ORC-ACS and non-replicating ACS sequences (nrACS), that are not bound by ORC. In this study, DNA properties such as base composition, correlation, sequence dependent thermodynamic and DNA structural profiles, and their positions have been considered for characterizing ORC-ACS and nrACS. Analysis reveals that ORC-ACS depict marked differences in nucleotide composition and context features in its vicinity compared to nrACS. Interestingly, an A-rich motif was also discovered in ORC-ACS sequences within its nucleosome-free region. Profound changes in the conformational features, such as DNA helical twist, inclination angle and stacking energy between ORC-ACS and nrACS were observed. Distribution of ACS motifs in the non-coding segments points to the locations of ORC-ACS which are found far away from the adjacent gene start position compared to nrACS thereby enabling an accessible environment for ORC-proteins. Our attempt is novel in considering the contextual view of ACS and its flanking region along with nucleosome positioning in the S. cerevisiae genome and may be useful for any computational prediction scheme. PMID:27508123

  19. Autographa californica multiple nucleopolyhedrovirus gene ac81 is required for nucleocapsid envelopment.

    Dong, Fang; Wang, Jinwen; Deng, Riqiang; Wang, Xunzhang

    2016-08-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly pathogenic Baculoviridae that targets insects, whose core gene, ac81, has an unknown function. To determine the role of ac81 in the life cycle of AcMNPV, an ac81-knockout (Ac-81KO-GP) was constructed through homologous recombination in Escherichia coli. We determined that no budded virions were produced in Ac-81KO-GP-transfected Sf9 cells, while there was no effect on viral DNA replication. Electron microscopy (EM) analysis revealed that occlusion-derived virions (ODVs) envelopment and the subsequent embedding of virions into occlusion bodies (OBs) were aborted due to ac81 deletion. Interestingly, confocal microscopy and immunofluorescence analysis revealed that Ac81 was predominantly localized to the ring zone of nuclei during the late phase of infection. In addition, Ac81 was localized to the mature and premature ODVs in virus-infected cells within the ring zone as revealed by immuno-electron microscopy (IEM) analysis. Furthermore, we determined that Ac81 contained a functional hydrophobic transmembrane (TM) domain, whose deletion resulted in a phenotype similar to that of Ac-81KO-GP. These results suggest that Ac81 might be a TM protein that played an important role in nucleocapsid envelopment. PMID:27212683

  20. Biocontrol activity of Paenibacillus polymyxa AC-1 against Pseudomonas syringae and its interaction with Arabidopsis thaliana.

    Hong, Chi Eun; Kwon, Suk Yoon; Park, Jeong Mee

    2016-04-01

    Paenibacillus polymyxa AC-1 (AC-1) is a plant growth-promoting rhizobacterium (PGPR) that has been used as a soil inoculant for biocontrol of plant pathogenic fungi and to promote plant growth. In this study, we examine the effects of AC-1 on the bacterial phytopathogen Pseudomonas syringae and internal colonization of AC-1 by counting bacterial populations that colonize plants. AC-1 inhibited the growth of both P. syringae pv. tomato DC3000 (Pst) and P. syringae pv. tabaci (Pta) in a concentration-dependent manner in in vitro assays. Upon treatment of AC-1 dropping at root tip of axenically grown Arabidopsis, we found that most of the AC-1 was detected in interior of leaves of Arabidiopsis plants rather than roots after 5 days post infection, indicating systemic spreading of AC-1 occur. We examined further AC-1 colonization patterns in Arabidopsis mutants deficient in phytohormone signaling pathways. These results indicated that abscisic acid (ABA) and jasmonic acid (JA) signaling pathways positively and negatively contributed, respectively, to AC-1 colonization of leaves, whereas epiphytic accumulation of AC-1 around root tissues was not affected. This study shows that AC-1 is an effective biocontrol agent to suppress P. syringae growth, possibly owing to its colonization patterns as a leaf-inhabiting endophyte. The results showed in this work will help to expand our understanding of the mode of action of AC-1 as a biological control agent and consequently, its application in agriculture. PMID:26946374

  1. Expression and immunocytochemical analysis of Autographa californica nucleopolyhedrovirus (AcMNPV) orf74 gene

    SHI-HENG AN; ZHONG-JIANG GUO; XIN-MING YIN

    2006-01-01

    Autographa californica nucleopolyhedrovirus orf74 (Ac74) is located between 62 311 and 63 108bp in the AcMNPV genome, which encodes 265 amino acid residues with a predicted 31 kDa molecular weight. The homologues of Ac74 were searched using BLASTP in protein databases, GenBank/EMBL and SWISS-PROT. The result revealed that deduced Ac74 protein was homologous to the predicted products from 10 lepidoptera NPV ORFs. The multiple sequence alignments of Ac74 and its 10 homologues manifested only one amino acid residue was completely conserved. The transcript analysis revealed that the transcript of Ac74 was detected from 24-72 hours post-infection (hpi). The product of Ac74was detected at 24 hpi and lasted until 72 bpi by Western blot using anti-Ac74 antiserum,consistent with reverse transcriptase polymerase chain reaction results. These results suggested Ac74 was expressed during the later stages of infection. The product of Ac74 was 31 kDa in size, consistent with predicted molecular weight. The subcellular localization of Ac74 proteins manifested Ac74 protein in the cytoplasm, and was hardly present in the nucleus at 24 bpi. The fluorescence was also observed in polyhedra, except cytoplasm at 72hpi. Together, Ac74 is a functional protein with 31kDa molecular weight and is located in the cytoplasm and the polyhedra.

  2. Heat Transfer Analysis for Industrial AC Electric Arc Furnace

    (U)nal (C)amdali; Murat Tun(c)

    2005-01-01

    The heat transfer analysis was performed for an AC electric arc furnace (EAF). Heat losses by conduction, convection and radiation from outer surface, roof, bottom and electrodes of EAF were determined in detail. Some suggestions about decreasing heat losses were presented.

  3. Current Control of Grid Converters Connected with Series AC Capacitor

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang;

    2015-01-01

    The series ac capacitor has recently been used with the transformerless grid-connected converters in the distribution power grids. The capacitive characteristic of the resulting series LC filter restricts the use of conventional synchronous integral or stationary resonant current controllers. Thus...

  4. Offshore windfarm connection with low frequency AC transmission technology

    Qin, Nan; Xu, Zhao; You, Shi;

    2009-01-01

    This paper investigates the feasibility of using the low frequency AC transmission (LFAC) system, e.g. fraction of 50 Hz or 60 Hz, for connecting the large offshore wind farm to the grid by modelling and simulation. The LFAC system improves the transmission capacity and distance compared to the c...

  5. AcTA: Accessdatabase Telen met toekomst - Alterra

    Smit, A.; Zwart, K.B.

    2003-01-01

    Binnen het project Telen met toekomst wordt een groot aantal metingen verricht, die op een overzichtelijke manier moeten worden opgeslagen. Er is gekozen voor en relationele database in MS-Access. De database zal AcTA worden genoemd (Access-database voor Telen met toekomst Alterra). Dit rapport bevat de beschrijving van de structuur van de database.

  6. Combined AC electroosmosis and dielectrophoresis for controlled rotation of microparticles.

    Walid Rezanoor, Md; Dutta, Prashanta

    2016-03-01

    Electrorotation is widely used for characterization of biological cells and materials using a rotating electric field. Generally, multiphase AC electric fields and quadrupolar electrode configuration are needed to create a rotating electric field for electrorotation. In this study, we demonstrate a simple method to rotate dielectrophoretically trapped microparticles using a stationary AC electric field. Coplanar interdigitated electrodes are used to create a linearly polarized nonuniform AC electric field. This nonuniform electric field is employed for dielectrophoretic trapping of microparticles as well as for generating electroosmotic flow in the vicinity of the electrodes resulting in rotation of microparticles in a microfluidic device. The rotation of barium titanate microparticles is observed in 2-propanol and methanol solvent at a frequency below 1 kHz. A particle rotation rate as high as 240 revolutions per minute is observed. It is demonstrated that precise manipulation (both rotation rate and equilibrium position) of the particles is possible by controlling the frequency of the applied electric field. At low frequency range, the equilibrium positions of the microparticles are observed between the electrode edge and electrode center. This method of particle manipulation is different from electrorotation as it uses induced AC electroosmosis instead of electric torque as in the case of electrorotation. Moreover, it has been shown that a microparticle can be rotated along its own axis without any translational motion. PMID:27014394

  7. Evolution of ac conductivity in nonequilibrium warm dense gold

    Using a chirped pulse probe technique, we have obtained single-shot measurements of temporal evolution of ac conductivity at 1.55 eV (800 nm) during electron energy relaxation in nonequilibrium warm dense gold with energy densities up to 4.1 MJ/kg (8*1010 J/m3). The results uncover important changes that have been masked in an earlier experiment. Equally significant, they provide valuable tests of an ab initio model for the calculation of electron heat capacity, electron-ion coupling, and ac conductivity in a single, first principles framework. While measurements of the real part of ac conductivity corroborate our theoretical temperature-dependent electron heat capacity, they point to an electron-ion coupling factor of 2.2*1016 W/m3K, significantly below that predicted by theory. In addition, measurements of the imaginary part of ac conductivity reveal the need to improve theoretical treatment of intraband contributions at very low photon energy. (authors)

  8. Exchange anisotropy determined by magnetic field dependence of ac susceptibility

    Rodríguez-Suárez, R. L.; Vilela Leão, L. H.; de Aguiar, F. M.; Rezende, S. M.; Azevedo, A.

    2003-10-01

    ac susceptibility measurements of ferromagnetic/antiferromagnetic (FM/AF) bilayers are usually performed as a function of the temperature. In this work we describe measurements of transverse biased ac susceptibility (χt) of FM/AF bilayers as a function of the applied magnetic field H0. The measurements were carried out at room temperature by means of an ac magneto-optical Kerr effect susceptometer. The χt-1(H0) dependence, at the saturation magnetization regime, exhibits a linear behavior with the applied field parallel and perpendicular to the exchange bias direction. The linear extrapolation of χt-1 versus H0 cuts the abscissa at asymmetrical values of field due to the exchange bias coupling. The inverse susceptibility is calculated in the saturation regime by a model, which takes into account the free energy of both layers plus a term corresponding to the interfacial coupling. The exchange coupling field (HE) and uniaxial anisotropy (HU) are extracted from the best fit to the experimental results. The results obtained are crosschecked by those obtained from ferromagnetic resonance (FMR) and dc magnetometry. The measurements of the exchange bias and the uniaxial field in all of the three analyzed bilayers gave values that are consistently lower when measured by FMR than those obtained by ac and dc magnetometry. It is argued that the apparently discrepant values of HE and HU, obtained by different techniques, might be explained by existence of unstable AF grains at the AF/FM interface.

  9. Introducing AC Inductive Reactance with a Power Tool

    Bryant, Wesley; Baker, Blane

    2016-01-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance…

  10. Droop-free Distributed Control for AC Microgrids

    Nasirian, Vahidreza; Shafiee, Qobad; Guerrero, Josep M.;

    2016-01-01

    A cooperative distributed secondary/primary control paradigm for AC microgrids is proposed. This solution replaces the centralized secondary control and the primary-level droop mechanism of each inverter with three separate regulators: voltage, reactive power, and active power regulators. A spars...

  11. On Conformal Field Theories With Extremal a/c Values

    Zhiboedov, Alexander

    2013-01-01

    Unitary conformal field theories (CFTs) are believed to have positive (non-negative) energy correlators. Energy correlators are universal observables in higher-dimensional CFTs built out of integrated Wightman functions of the stress-energy tensor. We analyze energy correlators in parity invariant four-dimensional CFTs. The goal is to use the positivity of energy correlators to further constrain unitary CFTs. It is known that the positivity of the simplest one-point energy correlator implies that 1/3 <= a/c <= 31/18 where a and c are the Weyl anomaly coefficients. We use the positivity of higher point energy correlators to show that CFTs with extremal values of a/c have trivial scattering observables. More precisely, for a/c=1/3 and a/c=31/18 all energy correlators are fixed to be the ones of the free boson and the free vector theory correspondingly. Similarly, we show that the positivity and finiteness of energy correlators together imply that the three-point function of the stress tensor in a CFT cann...

  12. Magnetophoresis of neutral particles in AC electric field

    Ovchinnikov, A. A.

    2002-01-01

    It has been shown that under joint action of DC magnetic and AC electric fields neutral particles (atoms,molecules,nano-size particles etc.) nearby interface move with permanent velocity along the surface. The driving force depends on non-linear dynamical properties of polarization of the particles and a coupling between the polarisation and the position of the particles on a surface.

  13. A simple technique for a.c. conductivity measurements

    R Padma Suvarna; K Raghavendra Rao; K Subbarangaiah

    2002-12-01

    An inexpensive, indigenous and a simple electronic instrument based on voltage follower, current–to–voltage converter, zero crossing detector and a phase detector has been developed for measurement of a.c. conductivity. Real and imaginary parts of complex impedance are determined for a given sample as a function of frequency and the given sample is represented by a pure electronic model.

  14. Acústica, fluidos y termodinámica

    Beléndez Vázquez, Augusto

    1992-01-01

    Acústica. Estática de fluidos. Dinámica de fluidos y fluidos reales. Temperatura y propagación del calor. Primer principio de la Termodinámica. Gases ideales. Segundo principio de la Termodinámica.

  15. Dielectric relaxation and ac conductivity of sodium tungsten phosphate glasses

    B Singh; P S Tarsikka; L Singh

    2002-10-01

    Studies of dielectric relaxation and ac conductivity have been made on three samples of sodium tungsten phosphate glasses over a temperature range of 77–420 K. Complex relative permittivity data have been analyzed using dielectric modulus approach. Conductivity relaxation frequency increases with the increase of temperature. Activation energy for conductivity relaxation has also been evaluated. Measured ac conductivity (m()) has been found to be higher than dc at low temperatures whereas at high temperature m() becomes equal to dc at all frequencies. The ac conductivity obeys the relation ac() = A over a considerable range of low temperatures. Values of exponent are nearly equal to unity at about 78 K and the values decrease non-linearly with the increase of temperature. Values of the number density of states at Fermi level ((F)) have been evaluated at 80 K assuming values of electron wave function decay constant to be 0.5 (Å)-1. Values of (F) have the order 1020 which are well within the range suggested for localized states. Present values of (F) are smaller than those for tungsten phosphate glasses.

  16. Financial Analysis - AC Sparta Praha a.s.

    Mayer, David

    2010-01-01

    This thesis analyzes and assesses the financial situation of the Czech football club AC Sparta Praha football, a. s. There are used the classical methods of financial analysis in this thesis, taking into account the specifics of the business environment. Considerable attention is paid to comparison with Czech and foreign football clubs.

  17. Evaluating conversion of AC power transmission lines to DC

    Edris, A. [EPRI, Palo Alto, CA (United States); Barthold, L. [IMod Inc., Lafayette, LA (United States); Douglass, D. [Power Delivery Consultants, Ballston Lake, NY (United States); Litzenberger, W. [Litzenberger Consultant (United States); Woodford, D. [Electranix, Winnipeg, MB (Canada)

    2008-07-01

    Conversion of alternating current (AC) transmission lines has been of significant interest for several years but has never been implemented to expand transmission line capacity or improve system security. This paper outlined the procedures necessary to identify and assess feasibility of specific AC to direct current (DC) conversion opportunities, with special focus on emerging DC transmission technologies. The paper outlined the process for investigating the conversion of an AC transmission line to DC. The investigation examined both bipole and tripole applications. A summary of the characteristics for alternative DC conversion configuration was presented. These characteristics included maximum transfer capability; redundancy; losses; overhead ratio; switching requirements; reactive power requirement; and accommodation of taps. The challenges and objectives of the project were also described. The paper provided a summary of the cost and benefit analysis for the various AC to DC conversion technologies for the Grand Coulee to Olympia transmission line. It was concluded that the project was particularly timely in that current work on the prospect of major North American system segmentation could benefit substantially, both technically and economically by having inter-system links take fuller advantage of the inherent DC capability of the circuits involved, thereby encouraging greater inter-regional energy exchange and providing the basis for lower energy supply costs. 12 refs., 2 tabs., 3 figs., 1 appendix.

  18. Aragonite coating solutions (ACS) based on artificial seawater

    Graphical abstract: - Highlights: • Developed completely inorganic solutions for the deposition of monolayers of aragonite spherules (or ooids). • Solutions mimicked the artificial seawater. • Biomimetic crystallization was performed at the tropical sea surface temperature of 30 °C. - Abstract: Aragonite (CaCO3, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca10(PO4)6(OH)2), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry

  19. Aragonite coating solutions (ACS) based on artificial seawater

    Tas, A. Cuneyt, E-mail: c_tas@hotmail.com

    2015-03-01

    Graphical abstract: - Highlights: • Developed completely inorganic solutions for the deposition of monolayers of aragonite spherules (or ooids). • Solutions mimicked the artificial seawater. • Biomimetic crystallization was performed at the tropical sea surface temperature of 30 °C. - Abstract: Aragonite (CaCO{sub 3}, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry.

  20. A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller

    Ahmet ALTINTAŞ

    2009-04-01

    Full Text Available A lot of topologies of pulse-width modulated (PWM-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with ability of generating fewer harmonics. In the proposed control method, both the traditional AC voltage controllers and the PWM-AC controllers are combined; and smaller THD values are obtained. Thus, the harmonic pollution in the power system will be reduced; and consequently, the power quality will be increased. For this purpose, computer simulations are performed in order to investigate the proposed controller performance. The obtained results are compared with the conventional PWM-AC controller.

  1. Expression characteristics of CS-ACS1, CS-ACS2 and CS-ACS3, three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in cucumber (Cucumis sativus L.) fruit under carbon dioxide stress.

    Mathooko, F M; Mwaniki, M W; Nakatsuka, A; Shiomi, S; Kubo, Y; Inaba, A; Nakamura, R

    1999-02-01

    We investigated the expression pattern of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes, CS-ACS1, CS-ACS2 and CS-ACS3 in cucumber (Cucumis sativus L.) fruit under CO2 stress. CO2 stress-induced ethylene production paralleled the accumulation of only CS-ACS1 transcripts which disappeared upon withdrawal of CO2. Cycloheximide inhibited the CO2 stress-induced ethylene production but superinduced the accumulation of CS-ACS1 transcript. At higher concentrations, cycloheximide also induced the accumulation of CS-ACS2 and CS-ACS3 transcripts. In the presence of CO2 and cycloheximide, the accumulation of CS-ACS2 transcript occurred within 1 h, disappeared after 3 h and increased greatly upon withdrawal of CO2. Inhibitors of protein kinase and types 1 and 2A protein phosphatases which inhibited and stimulated, respectively, CO2 stress-induced ethylene production had little effect on the expression of these genes. The results presented here identify CS-ACS1 as the main ACC synthase gene responsible for the increased ethylene biosynthesis in cucumber fruit under CO2 stress and suggest that this gene is a primary response gene and its expression is under negative control since it is expressed by treatment with cycloheximide. The results further suggest that the regulation of CO2 stress-induced ethylene biosynthesis by reversible protein phosphorylation does not result from enhanced ACC synthase transcription. PMID:10202812

  2. Transposition of Ac from the P Locus of Maize into Unreplicated Chromosomal Sites

    Chen, Jychian; Greenblatt, Irwin M.; Dellaporta, Stephen L.

    1987-01-01

    We have analyzed donor and target sites of the mobile element Activator (Ac) that are altered as a result of somatic transposition from the P locus in maize. Previous genetic analysis has indicated that the two mitotic daughter lineages which result from Ac transposition from P differ in their Ac constitution at the P locus. Both lineages, however, usually contain transposed Ac elements which map to the same genetic position. Using methylation-sensitive restriction enzymes and genomic blot a...

  3. A transgenic system for generation of transposon Ac/Ds-induced chromosome rearrangements in rice

    Yu, Chuanhe; Han, FangPu; Zhang, Jianbo; Birchler, James; Peterson, Thomas

    2012-01-01

    The maize Activator (Ac)/Dissociation (Ds) transposable element system has been used in a variety of plants for insertional mutagenesis. Ac/Ds elements can also generate genome rearrangements via alternative transposition reactions which involve the termini of closely linked transposons. Here, we introduced a transgene containing reverse-oriented Ac/Ds termini together with an Ac transposase gene into rice (Oryza sativa ssp. japonica cv. Nipponbare). Among the transgenic progeny, we identifie...

  4. Control of hybrid AC/DC microgrid under islanding operational conditions

    Ding, G.; Gao, F.; Zhang, S.;

    2014-01-01

    interlinking converter with DC-link capacitor or energy storage, which will devote to the proper power sharing between AC and DC sub-microgrids to maintain AC and DC side voltage stable, is reviewed. Combining the specific control methods developed for AC and DC sub-microgrids with interlinking converter, the...

  5. AC Losses in the MICE Channel Magnets -- Is This a Curse or aBlessing?

    Green, M.A.; Wu, H.; Wang, L.; Kai, L.L.; Jia, L.X.; Yang, S.Q.

    2008-01-31

    This report discusses the AC losses in the MICE channelmagnets during magnet charging and discharging. This report talks aboutthe three types of AC losses in the MICE magnets; the hysteretic AC lossin the superconductor, the coupling AC loss in the superconductor and theeddy current AC loss in the magnet mandrel and support structure. AClosses increase the heat load at 4 K. The added heat load increases thetemperature of the second stage of the cooler. In addition, AC losscontributes to the temperature rise between the second stage cold headand the high field point of the magnet, which is usually close to themagnet hot spot. These are the curses of AC loss in the MICE magnet thatcan limit the rate at which the magnet can be charge or discharged. Ifone is willing to allow some of the helium that is around the magnet toboil away during a magnet charge or discharge, AC losses can become ablessing. The boil off helium from the AC losses can be used to cool theupper end of the HTS leads and the surrounding shield. The AC losses arepresented for all three types of MICE magnets. The AC loss temperaturedrops within the coupling magnet are presented as an example of how boththe curse and blessing of the AC losses can be combined.

  6. AC losses and transient field stability of PF-FSJS sample

    This series of 17 slides deals with AC losses and transient field stability of poloidal field full-size-joint sample) which is relevant to the poloidal field coils of ITER. The topic is divided into 6 parts: 1) general - AC losses, 2) conductor magnetization, 3) conductor calorimetry, 4) conclusion on AC losses, 5) stability, and 6) conclusion on stability

  7. AC losses and transient field stability of PF-FSJS sample

    Zani, L

    2003-07-01

    This series of 17 slides deals with AC losses and transient field stability of poloidal field full-size-joint sample) which is relevant to the poloidal field coils of ITER. The topic is divided into 6 parts: 1) general - AC losses, 2) conductor magnetization, 3) conductor calorimetry, 4) conclusion on AC losses, 5) stability, and 6) conclusion on stability.

  8. 21 CFR 880.5510 - Non-AC-powered patient lift.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport...

  9. Advanced reliability improvement of AC-modules (ARIA)

    The AC-module is a relatively new development in PV-system technology and offers significant advantages over conventional PV-systems with a central inverter : e.g. increased modularity, ease of installation and freedom of system design. The Netherlands and Switzerland have a leading position in the field of AC-modules, both in terms of technology and of commercial and large-scale application. An obstacle towards large-scale market introduction of AC-modules is that the reliability and operational lifetime of AC-modules and the integrated inverters in particular are not yet proven. Despite the advantages, no module-integrated inverter has yet achieved large scale introduction. The AC-modules will lower the barrier towards market penetration. But due to the great interest in the new AC-module technology there is the risk of introducing a not fully proven product. This may damage the image of PV-systems. To speed up the development and to improve the reliability, research institutes and PV-industry will address the aspects of reliability and operational lifetime of AC-modules. From field experiences we learn that in general the inverter is still the weakest point in PV-systems. The lifetime of inverters is an important factor on reliability. Some authors are indicating a lifetime of 1.5 years, whereas the field experiences in Germany and Switzerland have shown that for central inverter systems, an availability of 97% has been achieved in the last years. From this point of view it is highly desirable that the operational lifetime and reliability of PV-inverters and especially AC-modules is demonstrated/improved to make large scale use of PV a success. Module Integrated Inverters will most likely be used in modules in the power range between 100 and 300 Watt DC-power. These are modules with more than 100 cells in series, assuming that the module inverter will benefit from the higher voltage. Hot-spot is the phenomenon that can occur when one or more cells of a string

  10. Removal of pharmaceutically active compounds (PhACs) and toxicological response of Cyperus alternifolius exposed to PhACs in microcosm constructed wetlands.

    Yan, Qing; Feng, Guozhong; Gao, Xu; Sun, Chengxiao; Guo, Jin-song; Zhu, Zhiwei

    2016-01-15

    This study investigated the effects of selected four pharmaceutically active compounds (PhACs) (carbamazepine, sulfamethoxazole, ofloxacin, and roxithromycin) on the photosynthesis and antioxidant enzymes of Cyperus alternifolius in constructed wetlands (CWs). Moreover, the removal and kinetics of PhACs in CWs were evaluated to explore the related removal mechanisms. Results showed that C. alternifolius can uptake and withstand certain PhACs. The PhAC tolerance of C. alternifolius might be attributed to their capacity to maintain relatively normal photosynthetic activity and elevated antioxidative defense. CWs offered comparable or even higher removal efficiencies for the selected PhACs compared with conventional WWTPs. The removal of the target PhACs was enhanced in the planted CWs versus the unplanted CWs mostly because of plant uptake and rhizosphere effects. In particular, carbamazepine, which is considered the most recalcitrant of the PhACs, was significantly reduced (p<0.05). The removal of target PhACs fitted into two distinct periods. The initial fast step (within the first 2 h) was essentially attributed to the adsorption onto the CW medium surface. The subsequent slow process (2-12 h) closely followed first-order kinetics probably because of the interaction between microorganisms and plants. The obtained results indicate that C. alternifolius can phytoremediate PhAC-contaminated waters in CWs. PMID:26465971

  11. A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller

    Ahmet ALTINTAŞ

    2009-01-01

    A lot of topologies of pulse-width modulated (PWM)-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with abi...

  12. Dicty_cDB: FC-AC21 [Dicty_cDB

    Full Text Available FC (Link to library) FC-AC21 (Link to dictyBase) - - - Contig-U15104-1 FC-AC21E (Li...nk to Original site) - - - - - - FC-AC21E 527 Show FC-AC21 Library FC (Link to library) Clone ID FC-AC21 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15104-1 Original site URL http://dict...ce KDSLDVIIFPEMVKLVGLTPNTMEKVLTYFQDNDTIDLSTFPMEIQVEQLSGKYIFICTH KQKDQRCGYCGPILVDQLRDQIKERSLEKEIQVFGTSHVGGHKY... Frames) Frame A: KDSLDVIIFPEMVKLVGLTPNTMEKVLTYFQDNDTIDLSTFPMEIQVEQLSGKYIFICTH KQ

  13. An improved inclusive measurement of Ac using the SLD detector

    The authors report a new measurement of Ac using data obtained by SLD in 1993--97. This measurement uses a vertex tag technique, where the selection of a c hemisphere is based on the reconstructed mass of the charm hadron decay vertex. The method uses the 3D vertexting capabilities of SLD's CCD vertex detector and the small and stable SLC beams to obtain a high c-event tagging efficiency and purity of 28% and 81%, respectively. Charged kaons identified by the CRID detector and the charge of the reconstructed vertex provide an efficient quark-antiquark tag. They obtain a preliminary result of Ac = 0.650 ± 0.041 ± 0.033

  14. Design and AC loss analysis of a superconducting synchronous motor

    This paper gives a conceptual design of a superconducting synchronous motor consisting of both high-temperature superconducting rotating field winding and armature winding. The AC losses of the armature winding of the motor have been investigated experimentally and numerically, by considering the self-field of the superconducting coils and the rotating magnetic field exposed on the armature winding. The recent developments of YBCO-coated conductors present the possibility of achieving a wholly superconducting machine of significantly smaller size and weight than a conventional machine. Both the rotating field winding and the armature winding are composed of YBCO high-temperature superconducting (HTS) coils. A low AC loss armature winding design has been developed for this superconducting synchronous motor. The performance of the machine was investigated by modelling with the finite-element method. The machine's torque is calculated from first principles by considering the angle between the field and the armature main flux lines

  15. Strongly nonlinear dynamics of electrolytes in large ac voltages

    Olesen, Laurits H; Bruus, Henrik

    2009-01-01

    We study the response of a model micro-electrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two novel features - significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasi-equilibrium structure of the double layers. The former leads to the prediction of "ac capacitive desalination", since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and co...

  16. Towards an AC-MOT of CaF

    Anderegg, Loic; Chae, Eunmi; Ravi, Aakash; Augenbraun, Benjamin; Hemmerling, Boerge; Drayna, Garrett; Hutzler, Nicholas; Collopy, Alejandra; Wu, Yewei; Ding, Shiqian; Ye, Jun; Ketterle, Wolfgang; Doyle, John

    2016-05-01

    Ultra-cold diatomic molecules have rich prospects as candidates to study controlled ultra-cold chemistry, strongly correlated systems and precision measurements. They are also considered as possible qubits in quantum computing and simulation schemes. We report on progress towards loading CaF into a molecular magneto-optical trap (MOT). An AC-MOT will be used to actively remix magnetic dark states via both polarization and magnetic field switching. In order to load a molecular MOT, we have successfully laser slowed a CaF beam to near the expected capture velocity. We describe our AC-MOT apparatus, which is designed to co-trap CaF and Li. We outline our planned study of CaF-Li collisions to explore the feasibility of sympathetically cooling molecules to ultra-cold temperatures.

  17. The minimization of ac phase noise in interferometric systems

    Filinski, Ignacy; Gordon, R A

    1994-01-01

    A simple step-by-step procedure, including several novel techniques discussed in the Appendices, is given for minimizing ac phase noise in typical interferometric systems such as two-beam interferometers, holographic setups, four-wave mixers, etc. Special attention is given to index of refraction...... fluctuations, direct mechanical coupling, and acoustic coupling, whose importance in determining ac phase noise in interferometric systems has not been adequately treated. The minimization procedure must be carried out while continuously monitoring the phase noise which can be done very simply by using a...... in optics. Thus, the necessity of eliminating the effects of index of refraction fluctuations which degrade the performance of all interferometers is pointed out as the first priority. A substantial decrease of the effects of all vibrating, rotating, or flowing masses (e.g., cooling lines) in direct...

  18. Improvement program for polycarbonate capacitors. [hermetically sealed, and ac wound

    Bailey, R. R.; Waterman, K. D.

    1973-01-01

    Hermetically sealed, wound, AC, polycarbonate capacitors incorporating design improvements recommended in a previous study were designed and built. A 5000 hour, 400 Hz ac life test was conducted using 384 of these capacitors to verify the adequacy of the design improvements. The improvements incorporated in the capacitors designed for this program eliminated the major cause of failure found in the preceding work, termination failure. A failure cause not present in the previous test became significant in this test with capacitors built from one lot of polycarbonate film. The samples from this lot accounted for 25 percent of the total test complement. Analyses of failed samples showed that the film had an excessive solvent content. This solvent problem was found in 37 of the total 46 failures which occurred in this test. The other nine were random failures resulting from causes such as seal leaks, foreign particles, and possibly wrinkles.

  19. Narrow strand YBCO Roebel cable for lowered AC loss

    We have constructed test lengths of Roebel cable from wide strips of second generation YBCO wire. The strand width is 2mm to allow for lowered AC losses in comparison with standard HTS wires. Up to 10 strands can be cut from the 40mm wide strip and assembled into a 10 strand cable with a transposition length of 90mm. Electrical measurements show good retention of critical current through the cutting and cabling processes. Initial AC loss measurements confirm the reduction expected from full width wire. Results from mechanical modeling are presented which have been used to optimise strand geometry to reduce stress concentrations. Manufacturing capability to produce up to 100m lengths has been demonstrated

  20. AC magnetization losses in striated YBCO-123/Hastelloy coated conductors

    In this work we present experimental results of reductions in AC magnetization losses due to a striation process in YBCO-123/Hastelloy coated conductors. The measurements were carried out in a sinusoidally varying external magnetic field, with amplitudes up to 100 mT, in a frequency range of 8.5-85.4 Hz, and at a temperature of 77 K. The field was oriented perpendicularly to the face of the tapes. Sample tapes were successively patterned into the form of narrow parallel strips, by means of a photoresist lithography and chemical wet etching technique. Experimental results are discussed in the framework of existing theoretical models for energy dissipation in thin films in perpendicular AC magnetic fields

  1. Effective nonlinear AC response to composite with spherical particles

    Chen Xiao-Gang; Liang Fang-Chu; Wei En-Bo

    2005-01-01

    An effective nonlinear alternative-current (AC) response to granular nonlinear-composite with spherical inclusions embedded in a host medium under the action of an external AC field is investigated by using a perturbation approach.The local potentials of composite at higher harmonics are derived both in a region of local inclusion particles and in a local host region under the action of a sinusoidal field E1 sinωt + E3sin3ωt. An effective nonlinear-response to composite and the relationship between the effective nonlinear-responses at the fundamental frequency and the third harmonics are also studied for the spherical inclusions in a dilute limit.

  2. Fiber Materials AC Impedance Characteristics and Principium Analysis

    Wang, Jianjun; Li, Xiaofeng

    With an invariable amplitude and variable frequency inspiriting, impedance of fiber materials rapidly decrease at first and then increase speedy followed with increasing of signal frequency. For the impedance curve of frequency is section of bathtub, this phenomenon is defined as alternating current electric conductive bathtub effect of fiber material. With analysis tools,of circuit theory and medium polarization theory, the phenomenon can be deeply detected that in AC electric field there are four different kind of currents in fiber material: absorbing current, conductance current, charging current and superficial current. With more analyzing it's discovered this phenomenon can be explained by medium polarize theory. Make using of fiber AC electric conductivity bathtub effect, fast testing equipment on fiber moisture regain can be invent, and disadvantages of conventional impedance technique, such as greatness test error and electrode polarization easily. This paper affords directions to design novel speediness fiber moisture test equipments in theory.

  3. Total loss of AC power analysis for EPR reactor

    Darnowski, Piotr, E-mail: piotr.darnowski@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Skrzypek, Eleonora, E-mail: eleonora.skrzypek@ncbj.gov.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); National Centre for Nuclear Research (NCBJ), A. Sołtana 7, 05-400 Otwock-Świerk (Poland); Mazgaj, Piotr, E-mail: piotr.mazgaj@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Świrski, Konrad [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Gandrille, Pascal [AREVA NP SAS, Tour AREVA, 1 place Jean Millier, 92084 Paris La Défense (France)

    2015-08-15

    Highlights: • Total loss of AC power (Station Blackout) was simulated for the EPR reactor model. • In-vessel phase of the accident is under consideration. • Comparison of MELCOR and MAAP results is presented. • MELCOR and MAAP results are comparable. - Abstract: In this paper the results of severe accident simulations for the EPR reactor in the case of loss of offsite power combined with total failure of all diesel generators (total loss of AC power) are presented. Calculations were performed with MELCOR 2.1 computer code for in-vessel phase of the accident. In this scenario, the unavailability of all offsite and onsite power sources and the lack of cooling leads directly to core degradation, material relocation to the lower plenum and rupture of the reactor pressure vessel. MELCOR results were compared qualitatively and quantitatively with MAAP4 code results and show a good agreement.

  4. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

    Dall' Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

    2016-07-01

    This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the controllers is grounded on a dual ..epsilon..-subgradient method, while semidefinite programming relaxations are advocated to bypass the non-convexity of AC OPF formulations. Global convergence of inverter output powers is analytically established for diminishing stepsize rules for cases where: i) computational limits dictate asynchronous updates of the controller signals, and ii) inverter reference inputs may be updated at a faster rate than the power-output settling time.

  5. Design and AC loss analysis of a superconducting synchronous motor

    Jiang, Q [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Majoros, M [Department of Materials Science and Engineering, Ohio State University (United States); Hong, Z [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Campbell, A M [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2006-11-15

    This paper gives a conceptual design of a superconducting synchronous motor consisting of both high-temperature superconducting rotating field winding and armature winding. The AC losses of the armature winding of the motor have been investigated experimentally and numerically, by considering the self-field of the superconducting coils and the rotating magnetic field exposed on the armature winding. The recent developments of YBCO-coated conductors present the possibility of achieving a wholly superconducting machine of significantly smaller size and weight than a conventional machine. Both the rotating field winding and the armature winding are composed of YBCO high-temperature superconducting (HTS) coils. A low AC loss armature winding design has been developed for this superconducting synchronous motor. The performance of the machine was investigated by modelling with the finite-element method. The machine's torque is calculated from first principles by considering the angle between the field and the armature main flux lines.

  6. On-Chip AC self-test controller

    Flanagan, John D.; Herring, Jay R.; Lo, Tin-Chee

    2009-09-29

    A system for performing AC self-test on an integrated circuit that includes a system clock for normal operation is provided. The system includes the system clock, self-test circuitry, a first and second test register to capture and launch test data in response to a sequence of data pulses, and a logic circuit to be tested. The self-test circuitry includes an AC self-test controller and a clock splitter. The clock splitter generates the sequence of data pulses including a long data capture pulse followed by an at speed data launch pulse and an at speed data capture pulse followed by a long data launch pulse. The at speed data launch pulse and the at speed data capture pulse are generated for a common cycle of the system clock.

  7. Bouncing of a Droplet on Superhydrophobic Surface in AC Electrowetting

    Kang, Kwan Hyoung; Lee, Seung Jun; Hong, Jiwoo

    2009-11-01

    Oscillation of a droplet is induced in ac electrowetting by time-dependent electrical wetting tension. A droplet placed on a superhydrophobic surface bounces up like a rubber ball when an ac signal is applied. The bouncing pattern is highly frequency dependent. We investigated how the shape deformation and bouncing of a droplet are affected by applied frequency. The droplet motion is analyzed with the spectral method. The droplet is modeled as a simple linear oscillator, and the mass and spring constants are determined based on analytical results. We found that bouncing occurs periodically at a resonance frequency of the droplet. The motion of a sessile droplet released from a fixed shape is analyzed based on the phase field method. The numerical results show qualitative agreement with the experimental results for a bouncing droplet. Details on the flow field inside a bouncing droplet will be discussed based on numerical results.

  8. Ac magnetic susceptibility study of in vivo nanoparticle biodistribution

    Gutierrez, L; Veintemillas-Verdaguer, S; Serna, C J; Morales, M P [Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Sor Juana Ines de la Cruz 3, Cantoblanco 28049, Madrid (Spain); MejIas, R; Barber, D F [Centro Nacional de BiotecnologIa, CNB-CSIC, Darwin 3, Cantoblanco 28049, Madrid (Spain); Lazaro, F J, E-mail: lucia@icmm.csic.es [Departamento de Ciencia y Tecnologia de Materiales y Fluidos, Universidad de Zaragoza, Maria de Luna 3, 50018, Zaragoza (Spain)

    2011-06-29

    We analysed magnetic nanoparticle biodistribution, before and after cytokine conjugation, in a mouse model by ac susceptibility measurements of the corresponding resected tissues. Mice received repeated intravenous injections of nanoparticle suspension for two weeks and they were euthanized 1 h after the last injection. In general, only 10% of the total injected nanoparticles after multiple exposures were found in tissues. The rest of the particles may probably be metabolized or excreted by the organism. Our findings indicate that the adsorption of interferon to DMSA-coated magnetic nanoparticles changes their biodistribution, reducing the presence of nanoparticles in lungs and therefore their possible toxicity. The specific targeting of the particles to tumour tissues by the use of an external magnetic field has also been studied. Magnetic nanoparticles were observed by transmission electron microscopy in the targeted tissue and quantified by ac magnetic susceptibility.

  9. ac power control in the Core Flow Test Loop

    This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. The initial considerations, design, and analysis of a closed-loop controller prototype are detailed. The design is then analyzed for improved performance possibilities and failure modes are investigated at length. A summary of the work completed to date and a proposed outline for continued development completes the report

  10. SNL software manual for the ACS Data Analytics Project.

    Stearley, Jon R.; McLendon, William Clarence, III; Rodrigues, Arun F.; Williams, Aaron S.; Hooper, Russell Warren; Robinson, David Gerald; Stickland, Michael G.

    2011-10-01

    In the ACS Data Analytics Project (also known as 'YumYum'), a supercomputer is modeled as a graph of components and dependencies, jobs and faults are simulated, and component fault rates are estimated using the graph structure and job pass/fail outcomes. This report documents the successful completion of all SNL deliverables and tasks, describes the software written by SNL for the project, and presents the data it generates. Readers should understand what the software tools are, how they fit together, and how to use them to reproduce the presented data and additional experiments as desired. The SNL YumYum tools provide the novel simulation and inference capabilities desired by ACS. SNL also developed and implemented a new algorithm, which provides faster estimates, at finer component granularity, on arbitrary directed acyclic graphs.

  11. Development of ac corona discharge modes at atmospheric pressure

    Corona discharges in gases exist under several distinctive forms. In this paper, a survey study has been made of ac corona discharge modes generated in some different gases fed in a wire-duct reactor with a constant rate of flowing at atmospheric pressure. The properties of different corona modes are analyzed under some condition transitions from Trichel pulses to a steady glow. In the course of the presented experimental work, numerous apparent contradictions with earlier observations necessitated further study and are given to provide more information on the physical mechanisms of the ac corona discharges. Furthermore, we have gained insight into some new technologies and applications of the environmentally friendly corona and plasma discharges.

  12. Security analysis of interconnected AC/DC systems

    Eriksson, Robert

    2015-01-01

    any line or transformer limits. Simulations were performed in a model of the Nordic power system where a dc grid is placed on top. The simulation supports the method as a tool to consider transfer limits in the grid to avoid violate the same and increase the security after a converter outage.......This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid....... The redistribution of power has a sudden effect on the power-flow in the interconnected ac system. This may cause overloading of lines and transformers resulting in disconnection of equipment, and as a consequence cascading failure. The PTDF is used as a method to analyze and avoid violating limits by in the dc...

  13. Low power DCVSL circuits employing AC power supply

    2002-01-01

    In view of changing the type of energy conversion in CMOS circuits, this paper investigates low power CMOS circuit design, which adopts a gradually changing power clock. First, we discuss the algebraic expressions and the corresponding properties of clocked power signals. Then the design procedure is summed up for converting complementary CMOS logic gates employing DC power to the power-clocked CMOS gates employing AC power. On this basis, the design of differential cascode voltage switch logic (DCVSL) circuits employing AC power clocks is proposed. The PSPICE simulations using a sinusoidal power-clock demonstrate that the designed power-clocked DCVSL circuit has a correct logic function and low power characteristics. Finally, an interface circuit to convert clocked signals into the standard logic levels of a CMOS circuit is proposed, and its validity is verified by computer simulations.

  14. Ac magnetic susceptibility study of in vivo nanoparticle biodistribution

    We analysed magnetic nanoparticle biodistribution, before and after cytokine conjugation, in a mouse model by ac susceptibility measurements of the corresponding resected tissues. Mice received repeated intravenous injections of nanoparticle suspension for two weeks and they were euthanized 1 h after the last injection. In general, only 10% of the total injected nanoparticles after multiple exposures were found in tissues. The rest of the particles may probably be metabolized or excreted by the organism. Our findings indicate that the adsorption of interferon to DMSA-coated magnetic nanoparticles changes their biodistribution, reducing the presence of nanoparticles in lungs and therefore their possible toxicity. The specific targeting of the particles to tumour tissues by the use of an external magnetic field has also been studied. Magnetic nanoparticles were observed by transmission electron microscopy in the targeted tissue and quantified by ac magnetic susceptibility.

  15. AC system stabilization via phase shift transformer with thyristor commutation

    Oliveira, Jose Carlos de; Guimaraes, Geraldo Caixeta; Moraes, Adelio Jose [Uberlandia Univ., MG (Brazil); Abreu, Jose Policarpo G. de [Escola Federal de Engenharia de Itajuba, MG (Brazil); Oliveira, Edimar Jose de [Juiz de Fora Univ., MG (Brazil)

    1994-12-31

    This article aims to present initially the constructive and operative forms of a phase-shift autotransformer which provides both magnitude and phase angle change through thyristor commutation, including a technic to reduce the number of thyristors. Following, it is proposed a control system to make such equipment an efficient AC system stabilizing tool. It is presented some simulation results to show the operation of this transformer in an electrical system. (author) 3 refs., 11 figs., 3 tabs.

  16. MD 349: Impedance Localization with AC-dipole

    Biancacci, Nicolo; Metral, Elias; Salvant, Benoit; Papotti, Giulia; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the distribution of the transverse impedance of the LHC by observing the phase advance variation with intensity between the machine BPMs. Four injected bunches with different intensities are excited with an AC dipole and the turn by turn data is acquired from the BPM system. Through post-processing analysis the phase variation along the machine is depicted and, from this information, first conclusions of the impedance distribution can be drawn.

  17. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

    Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

    2014-01-01

    This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the...

  18. Improved speed estimation in sensorless PM brushless AC drives

    Shen, J. X.; Zhu, Z.Q.; Howe, D.

    2002-01-01

    The application of flux-observer-based sensorless control to permanent-magnet brushless AC motor drives is described. Current methods of speed estimation are assessed, both theoretically and experimentally, and an improved method, which combines the best features of methods in which speed is derived from the differential of rotor position and from the ratio of the electromotive force to excitation flux linkage, is proposed. Its performance is verified experimentally.

  19. Power Loss Modeling of Isolated AC/DC Converter

    Ahmad Khan, Naveed

    2012-01-01

    Several research activities at KTH are carried out related to Isolated AC/DC converters in order to improve the design and efficiency. Concerning the improvement in the mentioned constraints, losses of the elements in the prototype converter are modeled in this thesis work. The obtained loss model is capable of calculating the losses under different circumstances. The individual contribution of losses for each element at different conditions can be obtained, which is further useful in improvi...

  20. Hybrid immersed interface-immersed boundary methods for AC dielectrophoresis

    Hossan, Mohammad Robiul; Dillon, Robert; Dutta, Prashanta

    2014-08-01

    Dielectrophoresis, a nonlinear electrokinetic transport mechanism, has become popular in many engineering applications including manipulation, characterization and actuation of biomaterials, particles and biological cells. In this paper, we present a hybrid immersed interface-immersed boundary method to study AC dielectrophoresis where an algorithm is developed to solve the complex Poisson equation using a real variable formulation. An immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles and an immersed boundary method is used for the fluid equations and particle transport. The convergence of the proposed algorithm as well as validation of the hybrid scheme with experimental results is presented. In this paper, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, this study eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. A comparative study between Maxwell stress tensor and point dipole methods for computing dielectrophoretic forces are presented. The hybrid method is used to investigate the physics of dielectrophoresis in microfluidic devices using an AC electric field. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis. Our numerical results also show that electrically neutral particles form a chain parallel to the applied electric field irrespective of their initial orientation when an AC electric field is applied. This proposed hybrid numerical scheme will help to better understand dielectrophoresis and to design and optimize microfluidic devices.

  1. Hybrid immersed interface-immersed boundary methods for AC dielectrophoresis

    Dielectrophoresis, a nonlinear electrokinetic transport mechanism, has become popular in many engineering applications including manipulation, characterization and actuation of biomaterials, particles and biological cells. In this paper, we present a hybrid immersed interface–immersed boundary method to study AC dielectrophoresis where an algorithm is developed to solve the complex Poisson equation using a real variable formulation. An immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles and an immersed boundary method is used for the fluid equations and particle transport. The convergence of the proposed algorithm as well as validation of the hybrid scheme with experimental results is presented. In this paper, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, this study eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. A comparative study between Maxwell stress tensor and point dipole methods for computing dielectrophoretic forces are presented. The hybrid method is used to investigate the physics of dielectrophoresis in microfluidic devices using an AC electric field. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis. Our numerical results also show that electrically neutral particles form a chain parallel to the applied electric field irrespective of their initial orientation when an AC electric field is applied. This proposed hybrid numerical scheme will help to better understand dielectrophoresis and to design and optimize microfluidic devices

  2. Hybrid immersed interface-immersed boundary methods for AC dielectrophoresis

    Hossan, Mohammad Robiul [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States); Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034-5209 (United States); Dillon, Robert [Department of Mathematics, Washington State University, Pullman, WA 99164-3113 (United States); Dutta, Prashanta, E-mail: dutta@mail.wsu.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States)

    2014-08-01

    Dielectrophoresis, a nonlinear electrokinetic transport mechanism, has become popular in many engineering applications including manipulation, characterization and actuation of biomaterials, particles and biological cells. In this paper, we present a hybrid immersed interface–immersed boundary method to study AC dielectrophoresis where an algorithm is developed to solve the complex Poisson equation using a real variable formulation. An immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles and an immersed boundary method is used for the fluid equations and particle transport. The convergence of the proposed algorithm as well as validation of the hybrid scheme with experimental results is presented. In this paper, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, this study eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. A comparative study between Maxwell stress tensor and point dipole methods for computing dielectrophoretic forces are presented. The hybrid method is used to investigate the physics of dielectrophoresis in microfluidic devices using an AC electric field. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis. Our numerical results also show that electrically neutral particles form a chain parallel to the applied electric field irrespective of their initial orientation when an AC electric field is applied. This proposed hybrid numerical scheme will help to better understand dielectrophoresis and to design and optimize microfluidic devices.

  3. AC Complex Impedance Analysis of Doped Strontium Titanate Multifunctional Ceramics

    2002-01-01

    Doped SrTiO3 capacitor-varistor multifunctional ceramics were fabricated by a single sintering process. AC compleximpedance analysis was performed to investigate electrical features ofgrains and grain boundaries for both as-reducedceramic and reoxidized ceramics. The results showed that the as-reduced ceramic exhibited inductive response athigh frequencies above 2 MHz, which is attributed to the contribution of electron behavior in semiconducting grains.The high frequency inductive response disappeared in impedance plots of reoxidized ceramics.

  4. Does a phase shift occur in an AC arc?

    Steinmetz, Charles Proteus

    2016-01-01

    This is a translation of a classic paper in German showing that the apparent power in an AC arc is larger than the active power although no phase shift exists between the voltage and the current, indicating that the reactive power vanishes. The phenomenon studied in this paper gave rise to a variety of mutually conflicting "power triangle" models relating the active, reactive, and apparent powers P, Q, and S whose merits are still under debate today.

  5. Eddy Current Rail Inspection Using AC Bridge Techniques

    Liu, Ze; Koffman, Andrew D; Waltrip, Bryan C; Wang, Yicheng

    2013-01-01

    AC bridge techniques commonly used for precision impedance measurements have been adapted to develop an eddy current sensor for rail defect detection. By using two detection coils instead of just one as in a conventional sensor, we can balance out the large baseline signals corresponding to a normal rail. We have significantly enhanced the detection sensitivity of the eddy current method by detecting and demodulating the differential signal of the two coils induced by rail defects, using a di...

  6. A Linear-Programming Approximation of AC Power Flows

    Coffrin, Carleton; Van Hentenryck, Pascal

    2012-01-01

    Linear active-power-only DC power flow approximations are pervasive in the planning and control of power systems. However, these approximations fail to capture reactive power and voltage magnitudes, both of which are necessary in many applications to ensure voltage stability and AC power flow feasibility. This paper proposes linear-programming models (the LPAC models) that incorporate reactive power and voltage magnitudes in a linear power flow approximation. The LPAC models are built on a co...

  7. DIAGNOSTIC FEATURES RESEARCH OF AC ELECTRIC POINT MOTORS

    S. YU. Buryak

    2014-05-01

    Full Text Available Purpose.Considerable responsibility for safety of operation rests on signal telephone and telegraph department of railway. One of the most attackable nodes (both automation systems, and railway in whole is track switches. The aim of this investigation is developing such system for monitoring and diagnostics of track switches, which would fully meet the requirements of modern conditions of high-speed motion and heavy trains and producing diagnostics, collection and systematization of data in an automated way. Methodology. In order to achieve the desired objectives research of a structure and the operating principle description of the switch electric drive, sequence of triggering its main units were carried out. The operating characteristics and settings, operating conditions, the causes of failures in the work, andrequirements for electric drives technology and their service were considered and analyzed. Basic analysis principles of dependence of nature of the changes the current waveform, which flows in the working circuit of AC electric point motor were determined. Technical implementation of the monitoring and diagnosing system the state of AC electric point motors was carried out. Findings. Signals taken from serviceable and defective electric turnouts were researched. Originality. Identified a strong interconnectionbetween the technical condition of the track switchand curve shape that describes the current in the circuit of AC electric point motor during operation which is based on the research processes that have influence on it during operation. Practical value. Shown the principles of the technical approach to the transition from scheduled preventive maintenance to maintenance of real condition for a more objective assessment and thus more rapid response to emerging or failures when they occur gradually, damages and any other shortcomings in the work track switch AC drives.

  8. "KOMANSKI PRIVJESCI" I POJASNI JEZIČAC S BRIBIRSKE GLAVICE

    Petrinec, Maja

    2007-01-01

    U radu se razmatraju polumjesečasti privjesci s obručastim dodacima u dnu s groba/ja u Kašiću i Velimu, te jezičac tipa Hohenberg s Bribirske glavice s obzirom na prikaz na zidnoj freski u crkvi Santa Maria Antiqua u Rimu, te se predlaže njihovo vremensko opredjeljivanje u drugu polovinu 8. st.

  9. Electric drives of traction rolling stocks with AC motors

    Leonas Povilas LINGAITIS; Liudvinavičius, Lionginas

    2006-01-01

    The paper considers the variation of circuit design of the electric drives in traction rolling stocks when traditional DC electric machines are replaced with AC electric machines. Simplified circuit diagrams of the electric drives using electric machines of non-commutator type are offered. Operational defects of DC traction engines are weighed against some positive characteristics of direct current series excitation in traction engines, determining their extensive use in the electric drives o...

  10. Research on AC Variable Frequency Speed Regulation System

    Ou Bing-Xian; Li Qing-Zhong; Yan Jun-Xia

    2013-01-01

    In view of shortcomings existing in shear speed control system, shearer AC speed regulating system is designed and studied. The mathematical model of three-phase asynchronous motor in rotating coordinate system is established, and PWM technology of space vector is discussed. Software and hardware of the asynchronous motor vector control variable frequency speed regulating system are designed. The simulation of system based on Matlab is made and the correctness and feasibility of the sys...

  11. AC Power Local Network with Multiple Power Routers

    Ryo Takahashi; Yutaro Kitamori; Takashi Hikihara

    2013-01-01

    Controlling power flow and achieving appropriate matching between power sources and loads according to the quality of energy is expected to be one of the approaches to reduce wasted energy consumption. A power router, proposed recently, has the capability of realizing circuit switching in a power distribution network. This study focuses on the feasibility of an AC power routing network system composed of multiple power routers. To evaluate the feasibility, we experimentally confirm the circui...

  12. The Autographa californica multiple nucleopolyhedrovirus ac110 gene encodes a new per os infectivity factor.

    Jiantao Liu; Zhu, Leyuan; Zhang, Shan; Deng, Zihao; Huang, Zhihong; Yuan, Meijin; Wu, Wenbi; Yang, Kai

    2016-08-01

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac110 gene is especially conserved in lepidopteran-specific baculoviruses and is uncharacterized. To investigate the role of ac110 in the baculovirus life cycle, an ac110-knockout (vAc110KO) and a repair (vAc110:HA) viruses were constructed in this study. Budded virion production and occlusion body formation were unaffected in vAc110KO-transfected or infected Sf9 cells. Intrahemocoelic injection of budded virions of vAc110KO killed Trichoplusia ni larvae as efficiently as the repair or the wild-type viruses. However, per os inoculation of occlusion bodies of vAc110KO failed to establish infection in T. ni larvae, while the repair virus was as efficient as the wild-type virus. Treatment with calcofluor white, a reagent that damages the peritrophic membrane, did not rescue the oral infectivity of vAc110KO. These results suggested that Ac110 is a new per os infectivity factor that may play a role after occlusion-derived virions pass through the peritrophic membrane during oral infection. PMID:27212681

  13. Performance testing of the AC propulsion ELX electric vehicle

    Kramer, W.E.; MacDowall, R.D.; Burke, A.F.

    1994-06-01

    Performance testing of the AC Propulsion ELX electric vehicle is described. Test data are presented and analyzed. The ELX vehicle is the first of a series of electric vehicles of interest to the California Air Resources Board. The test series is being conducted under a Cooperative Research and Development Agreement (CRADA) between the US Department of energy and the California Air Resources Board. The tests which were conducted showed that the AC Propulsion ELX electric vehicle has exceptional acceleration and range performance. when the vehicle`s battery was fully charged, the vehicle can accelerate from 0 to 96 km/h in about 10 seconds. Energy consumption and range tests using consecutive FUDS and HWFET Driving cycles (the all-electric cycle) indicate that the energy economy of the AC Propulsion ELX electric vehicle with regenerative braking is 97 W{center_dot}h/km, with a range of 153 km (95 miles). Computer simulations performed using the SIMPLEV Program indicate that the vehicle would have a range of 327 km (203 miles) on the all-electric cycle if the lead acid batteries were replaced with NiMH batteries having an energy density of 67 W{center_dot}h/kg. Comparisons of FUDS test data with and without regenerative braking indicated that regenerative braking reduced the energy consumption of the ELX vehicle by approximately 25%.

  14. The ACS-NUCL Division 50th Anniversary: Introduction

    Hobart, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-10

    The ACS Division of Nuclear Chemistry and Technology was initiated in 1955 as a subdivision of the Division of Industrial and Engineering Chemistry. Probationary divisional status was lifted in 1965. The Division’s first symposium was held in Denver in 1964 and it is fitting that we kicked-off the 50th Anniversary in Denver in the spring of 2015. Listed as a small ACS Division with only about 1,000 members, NUCL’s impact over the past fifty years has been remarkable. National ACS meetings have had many symposia sponsored or cosponsored by NUCL that included Nobel Laureates, U.S. Senators, other high-ranking officials and many students as speakers. The range of subjects has been exceptional as are the various prestigious awards established by the Division. Of major impact has been the past 30 years of the NUCL Nuclear Chemistry Summer Schools to help fill the void of qualified nuclear scientists and technicians. In celebrating the 50th Anniversary we honor the past, celebrate the present and shape the future of the Division and nuclear science and technology. To celebrate this auspicious occasion a commemorative lapel pin has been designed for distribution to NUCL Division members.

  15. On conformal field theories with extremal (a/c) values

    Unitary conformal field theories (CFTs) are believed to have positive (non-negative) energy correlators. Energy correlators are universal observables in higher-dimensional CFTs built out of integrated Wightman functions of the stress-energy tensor. We analyze energy correlators in parity invariant four-dimensional CFTs. The goal is to use the positivity of energy correlators to further constrain unitary CFTs. It is known that the positivity of the simplest one-point energy correlator implies that (1/3)≤(a/c)≤(31/18) where a and c are the Weyl anomaly coefficients. We use the positivity of higher point energy correlators to show that CFTs with extremal values of (a/c) have trivial scattering observables. More precisely, for (a/c)=(1/3) and (a/c)=(31/18) all energy correlators are fixed to be the ones of the free boson and the free vector theory correspondingly. Similarly, we show that the positivity and finiteness of energy correlators together imply that the three-point function of the stress tensor in a CFT cannot be proportional to the one in the theory of free boson, free fermion or free vector field

  16. AC electric field induced vortex in laminar coflow diffusion flames

    Xiong, Yuan

    2014-09-22

    Experiments were performed by applying sub-critical high-voltage alternating current (AC) to the nozzle of laminar propane coflow diffusion flames. Light scattering, laser-induced incandescence and laser-induced fluorescence techniques were used to identify the soot zone, and the structures of OH and polycyclic aromatic hydrocarbons (PAHs). Particle image velocimetry was adopted to quantify the velocity field. Under certain AC conditions of applied voltage and frequency, the distribution of PAHs and the flow field near the nozzle exit were drastically altered, leading to the formation of toroidal vortices. Increased residence time and heat recirculation inside the vortex resulted in appreciable formation of PAHs and soot near the nozzle exit. Decreased residence time along the jet axis through flow acceleration by the vortex led to a reduction in the soot volume fraction in the downstream sooting zone. Electromagnetic force generated by AC was proposed as a viable mechanism for the formation of the toroidal vortex. The onset conditions for the vortex formation supported the role of an electromagnetic force acting on charged particles in the flame zone. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  17. Effects of AC Electric Field on Small Laminar Nonpremixed Flames

    Xiong, Yuan

    2015-04-01

    Electric field can be a viable method in controlling various combustion properties. Comparing to traditional actuators, an application of electric field requires very small power consumption. Especially, alternating current (AC) has received attention recently, since it could modulate flames appreciably even for the cases when direct current (DC) has minimal effects. In this study, the effect of AC electric fields on small coflow diffusion flames is focused with applications of various laser diagnostic techniques. Flow characteristics of baseline diffusion flames, which corresponds to stationary small coflow diffusion flames when electric field is not applied, were firstly investigated with a particular focus on the flow field in near-nozzle region with the buoyancy force exerted on fuels due to density differences among fuel, ambient air, and burnt gas. The result showed that the buoyancy force exerted on the fuel as well as on burnt gas significantly distorted the near-nozzle flow-fields. In the fuels with densities heavier than air, recirculation zones were formed very close to the nozzle exit. Nozzle heating effect influenced this near-nozzle flow-field particularly among lighter fuels. Numerical simulations were also conducted and the results showed that a fuel inlet boundary condition with a fully developed velocity profile for cases with long fuel tubes should be specified inside the fuel tube to obtain satisfactory agreement in both the flow and temperature fields with those from experiment. With sub-critical AC applied to the baseline flames, particle image velocimetry (PIV), light scattering, laser-induced incandescence (LII), and laser-induced fluores- cence (LIF) techniques were adopted to identify the flow field and the structures of OH, polycyclic aromatic hydrocarbons (PAHs), soot zone. Under certain AC condi- tions of applied voltage and frequency, the distribution of PAHs and the flow field near the nozzle exit were drastically altered from the

  18. Image optimization procedures for the Fuji AC-1

    Freedman, Matthew T.; Mun, Seong K.; Pe, Einar V.; Lo, Shih-Chung B.; Nelson, Martha C.

    1993-06-01

    The Fuji AC-1 is a popular system for digital radiography with great potential, but for many the initial implementation of the system in a radiology service is frustrating experience for lack of effective support and a clear operational manual. Adjusting the image processing settings for site specific image optimization has been, for most users, difficult and confusing. The effect of each of the image processing parameters available on the Fuji AC-1 is not easily understood by users of the machine. The application manual that comes with the machine briefly defines the parameters and gives recommended settings for different types of examinations, but the manual does not provide the user with adequate information or a suggested method to allow the user to easily optimize the image for that user's site. This paper defines in more precise terms the meaning of the various parameters and suggests a method of procedure to optimize the parameters to each radiologists preference. The results are based on experiments and measurements we performed with a Fuji AC-1 +. This information should assist the radiologist to use a more systematic method of image quality improvement rather than the somewhat random trial and error process that current users have described.

  19. AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications

    Highlights: ► Se nanoparticles were synthesized using a reverse-microemulsion process. ► AC osmotic fluid flow repulses the particles from electrode edges. ► Dielectrophoretic force attracts the particles to electrode edges. ► Dielectrophoresis electrode showed non-ohmic behavior. ► The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspended materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V p−p> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V p−p> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices

  20. AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications

    Mahmoodi, Seyed Reza [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bayati, Marzieh, E-mail: m-bayati@tums.ac.ir [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hosseinirad, Somayeh [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Foroumadi, Alireza [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Gilani, Kambiz [Department of Pharmaceutics, School of Pharmacy, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Rezayat, Seyed Mahdi [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2013-03-15

    Highlights: ► Se nanoparticles were synthesized using a reverse-microemulsion process. ► AC osmotic fluid flow repulses the particles from electrode edges. ► Dielectrophoretic force attracts the particles to electrode edges. ► Dielectrophoresis electrode showed non-ohmic behavior. ► The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspended materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V {sub p−p}> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V {sub p−p}> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices.

  1. Mapping the conformational epitope of a neutralizing antibody (AcV1) directed against the AcMNPV GP64 protein

    The envelope glycoprotein GP64 of Autographa californica nucleopolyhedrovirus (AcMNPV) is necessary and sufficient for the acid-induced membrane fusion activity that is required for fusion of the budded virus (BV) envelope and the endosome membrane during virus entry. Infectivity of the budded virus (BV) is neutralized by AcV1, a monoclonal antibody (MAb) directed against GP64. Prior studies indicated that AcV1 recognizes a conformational epitope and does not inhibit virus attachment to the cell, but instead inhibits entry at a step following virus attachment. We found that AcV1 recognition of GP64 was lost upon exposure of GP64 to low pH (pH 4.5) and restored by returning GP64 to pH 6.2. In addition, the AcV1 epitope was lost upon denaturation of GP64 in SDS, but the AcV1 epitope was restored by refolding the protein in the absence of SDS. Using truncated GP64 proteins expressed in insect cells, we mapped the AcV1 epitope to a 24 amino acid region in the central variable domain of GP64. When sequences within the mapped AcV1 epitope were substituted with a c-Myc epitope and the resulting construct was used to replace wt GP64 in recombinant AcMNPV viruses, the modified GP64 protein appeared to function normally. However, an anti-c-Myc monoclonal antibody did not neutralize infectivity of those viruses. Because binding of the c-Myc MAb to the same site in the GP64 sequence did not result in neutralization, these studies suggest that AcV1 neutralization may result from a specific structural constraint caused by AcV1 binding and not simply by steric hindrance caused by antibody binding at this position in GP64

  2. The cultivar-specific expression patterns of MdACS3 gene and apple fruit ripening and quality

    Ethylene plays an important role in diverse physiological and developmental processes of plants. In apple, two ethylene biosynthesis genes, MdACS1 and MdACS3, are expressed in fruit tissues. While MdACS1 expresses at late ripening stages, expression of MdACS3 can be detected as early as 6 weeks bef...

  3. The role of cultivar-specific expression patterns of MdACS3 gene on apple fruit ripening and quality

    Ethylene plays an important role in diverse physiological and developmental processes of plants. In apple, two ethylene biosynthesis genes, MdACS1 and MdACS3, are expressed in fruit tissues. While MdACS1 expresses at late ripening stages, expression of MdACS3 can be detected as early as 6 weeks befo...

  4. Removal of nitrate ions from water by activated carbons (ACs)—Influence of surface chemistry of ACs and coexisting chloride and sulfate ions

    Ota, Kazunari; Amano, Yoshimasa; Aikawa, Masami; Machida, Motoi

    2013-07-01

    Adsorptive removal of nitrate ions in aqueous solution using activated carbons (ACs) was examined. After ash was removed from Filtrasorb 400 AC, oxidation and outgassing and several heat treatments were carried out to modify the textural and surface properties of ACs. AC oxidized with 8 M nitric acid followed by outgassing at 900 °C (Ox-9OG) exhibited the greatest Langmuir adsorption capacity and affinity for nitrate removal among the total 7 ACs examined. Influence of coexisting chloride and sulfate ions was investigated as well to inspect the nitrate adsorption sites. The highest amount of sites which adsorbed nitrate ions exclusively could be observed for Ox-9OG adsorbent even though as great as 250 times greater number of chloride or sulfate ions over nitrate ions were present in the same aqueous system. Some basic oxygen species on carbon were estimated to work as selective adsorption sites for nitrate ions.

  5. H3K36ac Is an Evolutionary Conserved Plant Histone Modification That Marks Active Genes.

    Mahrez, Walid; Arellano, Minerva Susana Trejo; Moreno-Romero, Jordi; Nakamura, Miyuki; Shu, Huan; Nanni, Paolo; Köhler, Claudia; Gruissem, Wilhelm; Hennig, Lars

    2016-03-01

    In eukaryotic cells, histones are subject to a large number of posttranslational modifications whose sequential or combinatorial action affects chromatin structure and genome function. We identified acetylation at Lys-36 in histone H3 (H3K36ac) as a new chromatin modification in plants. The H3K36ac modification is evolutionary conserved in seed plants, including the gymnosperm Norway spruce (Picea abies) and the angiosperms rice (Oryza sativa), tobacco (Nicotiana tabacum), and Arabidopsis (Arabidopsis thaliana). In Arabidopsis, H3K36ac is highly enriched in euchromatin but not in heterochromatin. Genome-wide chromatin immunoprecipitation sequencing experiments revealed that H3K36ac peaks at the 5' end of genes, mainly on the two nucleosomes immediately distal to the transcription start site, independently of gene length. H3K36ac overlaps with H3K4me3 and the H2A.Z histone variant. The histone acetyl transferase GCN5 and the histone deacetylase HDA19 are required for H3K36ac homeostasis. H3K36ac and H3K36me3 show negative crosstalk, which is mediated by GCN5 and the histone methyl transferase SDG8. Although H3K36ac is associated with gene activity, we did not find a linear relationship between H3K36ac and transcript levels, suggesting that H3K36ac is a binary indicator of transcription. PMID:26764380

  6. Construction and function of recombinant AcMNPV with double copies of v-cath gene

    2002-01-01

    Two recombinant baculoviruses, dciAcMNPV and dcdAcMNPV in which another copy of the v-cath gene controlled by ie1 promoter and polh promoter was inserted, were respectively constructed by the Bac-to-Bac system. The expression of the v-cath gene of the recombinant baculoviruses in Sf9 cells at different phases was investigated by SDS- PAGE and Western blot. The results showed that only recombinant virus dciAcMNPV containing late gene v-cath driven by early gene promoter could express V-CATH protein, cathepsin encoded by virus genome, 12 h post-infection and dcdAcMNPV containing late gene v-cath driven by late and very late gene promoters could express more V-CATH protein. Negative control ncAcMNPV, a mutant deleted v- cath gene, could not express V-CATH protein at all. The Spodopera exigua larvae were infected with viruses respectively and the results showed that the toxicity was as follows: dcdAcMNPV>dciAcMNPV>wtAcMNPV>ncAcMNPV. The toxicity of recombinant viruses and the characters of dead larvae showed that the v-cath gene was relative to viral toxicity and host liquefaction. Recombinant baculovirus dcdAcMNPV might be used as a new kind of safe viral-pes- ticide, because of its high toxicity obtained by adding another gene copy and changing the expression level of its own gene relative to virulence.

  7. Overexpressing mouse model demonstrates the protective role of Muc5ac in the lungs.

    Ehre, Camille; Worthington, Erin N; Liesman, Rachael M; Grubb, Barbara R; Barbier, Diane; O'Neal, Wanda K; Sallenave, Jean-Michel; Pickles, Raymond J; Boucher, Richard C

    2012-10-01

    MUC5AC, a major gel-forming mucin expressed in the lungs, is secreted at increased rates in response to infectious agents, implying that mucins exert a protective role against inhaled pathogens. However, epidemiological and pathological studies suggest that excessive mucin secretion causes airways obstruction and inflammation. To determine whether increased MUC5AC secretion alone produces airway obstruction and/or inflammation, we generated a mouse model overexpressing Muc5ac mRNA ~20-fold in the lungs, using the rCCSP promoter. The Muc5ac cDNA was cloned from mouse lungs and tagged internally with GFP. Bronchoalveolar lavage fluid (BALF) analysis demonstrated an approximate 18-fold increase in Muc5ac protein, which formed high-molecular-weight polymers. Histopathological studies and cell counts revealed no airway mucus obstruction or inflammation in the lungs of Muc5ac-transgenic (Muc5ac-Tg) mice. Mucus clearance was preserved, implying that the excess Muc5ac secretion produced an "expanded" rather than more concentrated mucus layer, a prediction confirmed by electron microscopy. To test whether the larger mucus barrier conferred increased protection against pathogens, Muc5ac-Tg animals were challenged with PR8/H1N1 influenza viruses and showed significant decreases in infection and neutrophilic responses. Plaque assay experiments demonstrated that Muc5ac-Tg BALF and purified Muc5ac reduced infection, likely via binding to α2,3-linked sialic acids, consistent with influenza protection in vivo. In conclusion, the normal mucus transport and absence of a pulmonary phenotype in Muc5ac-Tg mice suggests that mucin hypersecretion alone is not sufficient to trigger luminal mucus plugging or airways inflammation/goblet cell hyperplasia. In contrast, increased Muc5ac secretion appears to exhibit a protective role against influenza infection. PMID:23012413

  8. Concurrent Electroencephalography Recording During Transcranial Alternating Current Stimulation (tACS).

    Fehér, Kristoffer D; Morishima, Yosuke

    2016-01-01

    Oscillatory brain activities are considered to reflect the basis of rhythmic changes in transmission efficacy across brain networks and are assumed to integrate cognitive neural processes. Transcranial alternating current stimulation (tACS) holds the promise to elucidate the causal link between specific frequencies of oscillatory brain activity and cognitive processes. Simultaneous electroencephalography (EEG) recording during tACS would offer an opportunity to directly explore immediate neurophysiological effects of tACS. However, it is not trivial to measure EEG signals during tACS, as tACS creates a huge artifact in EEG data. Here we explain how to set up concurrent tACS-EEG experiments. Two necessary considerations for successful EEG recording while applying tACS are highlighted. First, bridging of the tACS and EEG electrodes via leaking EEG gel immediately saturates the EEG amplifier. To avoid bridging via gel, the viscosity of the EEG gel is the most important parameter. The EEG gel must be viscous to avoid bridging, but at the same time sufficiently fluid to create contact between the tACS electrode and the scalp. Second, due to the large amplitude of the tACS artifact, it is important to consider using an EEG system with a high resolution analog-to-digital (A/D) converter. In particular, the magnitude of the tACS artifact can exceed 100 mV at the vicinity of a stimulation electrode when 1 mA tACS is applied. The resolution of the A/D converter is of importance to measure good quality EEG data from the vicinity of the stimulation site. By following these guidelines for the procedures and technical considerations, successful concurrent EEG recording during tACS will be realized. PMID:26862814

  9. AC Motor Drive Fed by Renewable Energy Sources with PWM

    J. Pavalam

    2014-01-01

    Full Text Available In this fast aproaching nature of technology the ned of Electricity becomes a mandatory in developing technology. The ned of Electricity increases the power demand where the power demand met by the conventional sources of energy has some disadvantage of polution, this disadvantage can be decreased by the use of the Renewable energy sources like Fuel Cel and available solar energy. When a FUEL cel produces AC power, basicaly two stages are required for conversion first a bosting stage and second is inversion stage. In this paper the Bost inverter topology is achieved where in the conventional methods the normal DC - AC power conversion method is used where as in this paper the PWM based DC - AC inverter has ben used which is useful in reducing the harmonics in the output of the Inverter. The voltage controled output is produced in the bost inverter the curent controled output is taken from dc-dc bidirectional converter. The Fuel cel canot be relied as a whole so a Solar PV module is conected acros the Load so while the Sunlight days the PV arays generate power and in the night time the Fuel cel is used to generate power for the load. Since, the Fuel cel and PV arays can generate power in Partial load they are prefered than any other sources. When the output from the Solar PV aray is low or when the sunlight available is not eficient in generating the power a automatic switch over is provided in the junction betwen the Solar PV aray and Fuel cel so that whenever it hapens the switch automaticaly switch over to another source. The simulation results are presented to confirm the operational feature of the proposed system.

  10. Spectroscopic AC susceptibility imaging (sASI) of magnetic nanoparticles

    Ficko, Bradley W., E-mail: Bradley.W.Ficko@Dartmouth.edu; Nadar, Priyanka M.; Diamond, Solomon G.

    2015-02-01

    This study demonstrates a method for alternating current (AC) susceptibility imaging (ASI) of magnetic nanoparticles (mNPs) using low cost instrumentation. The ASI method uses AC magnetic susceptibility measurements to create tomographic images using an array of drive coils, compensation coils and fluxgate magnetometers. Using a spectroscopic approach in conjunction with ASI, a series of tomographic images can be created for each frequency measurement set and is termed sASI. The advantage of sASI is that mNPs can be simultaneously characterized and imaged in a biological medium. System calibration was performed by fitting the in-phase and out-of-phase susceptibility measurements of an mNP sample with a hydrodynamic diameter of 100 nm to a Brownian relaxation model (R{sup 2}=0.96). Samples of mNPs with core diameters of 10 and 40 nm and a sample of 100 nm hydrodynamic diameter were prepared in 0.5 ml tubes. Three mNP samples were arranged in a randomized array and then scanned using sASI with six frequencies between 425 and 925 Hz. The sASI scans showed the location and quantity of the mNP samples (R{sup 2}=0.97). Biological compatibility of the sASI method was demonstrated by scanning mNPs that were injected into a pork sausage. The mNP response in the biological medium was found to correlate with a calibration sample (R{sup 2}=0.97, p<0.001). These results demonstrate the concept of ASI and advantages of sASI. - Highlights: • Development of an AC susceptibility imaging model. • Comparison of AC susceptibility imaging (ASI) and susceptibility magnitude imaging (SMI). • Demonstration of ASI and spectroscopic ASI (sASI) using three different magnetic nanoparticle types. • SASI scan separation of three different magnetic nanoparticles samples using 5 spectroscopic frequencies. • Demonstration of biological feasibility of sASI.

  11. Laser-modulated ac measurement of high temperature thermopower

    Fan Zhen-Jun; Zhang Dian-Lin

    2005-01-01

    An experimental set-up for ac-measurement of thermopower between room temperature and 1200K by using modulated laser-heating has been developed. The method shows many advantages compared with the conventional dc-measurements: convenience, applicability to small samples, possibility to measure the anisotropy of single crystals,and capability to continuously trace the temperature dependence of thermopower. The thermopower of a very short piece of pure Pt was measured with the present set-up to test the reliability and accuracy of our new method.

  12. Strongly nonlinear dynamics of electrolytes in large ac voltages

    Olesen, Laurits Højgaard; Bazant, Martin Z.; Bruus, Henrik

    2010-01-01

    , ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features—significant salt depletion in the...... suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional...... nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena....

  13. Warning: safety risk with some Apple AC Wall Plug Adapters

    CERN IT department

    2016-01-01

    Dear Mac and iOS Users, Apple has determined that some of its two prong Apple AC wall plug adapters may break and create a risk of electrical shock.   CERN users can now exchange their affected Apple wall plug adapters at the Service Desk. To find out if your adapter is affected and for any further information concerning the procedure to follow to exchange it, please check the following URL: https://cern.service-now.com/service-portal/view-outage.do?n=OTG0028639.

  14. AC dipole based optics measurement and correction at RHIC

    Shen, X; Bai, M; White, S; Robert-Domolaize, G; Luo, Y; Marusic, A; Tomas, R

    2013-01-01

    Independent component analysis (ICA) was applied to the AC dipole based optics measurement at RHIC to extract beta functions as well as phase advances at each BPM. Existence of excessive beta-beat was observed in both rings of RHIC at polarized proton store energy. A unique global optics correction scheme was then developed and tested successfully during the RHIC polarized proton run in 2013. The feasibility of using horizontal closed orbit bump at sextupole for arc beta-beat correction was also demonstrated.

  15. SCR-controlled digitally programmable ac power supply

    A digitally programmable ac power supply was designed, built, and tested. Its output voltage may be programmed to be any one of 41 equally spaced voltage levels and may be switched from any level to any other level in one 60-Hz period (16.67 ms). The switching of voltages is accomplished by turning on and off individual silicon-controlled rectifiers (SCR's) in a network of 14 pairs of SCR's. The concept of this power supply is readily extendable to more or fewer voltage levels or higher or lower output currents or voltages than the particular supply described

  16. Total synthesis and allelopathic activity of cytosporones A-C

    Zamberlam, Charles E.M.; Meza, Alisson; Lima, Denis P. de; Beatriz, Adilson [Centro de Ciencias Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil); Leite, Carla Braga; Marques, Maria Rita [Centro de Ciencias Biologicas e da Saude, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil)

    2012-07-01

    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  17. Photovoltaic Simplified Boost Z Source Inverter for Ac Module Applications

    J. Sam Alaric

    2014-08-01

    Full Text Available This study mainly proposed PV z source boost inverter used to boundary grid or ac module applications. Separate types of converter used for solar system due to its current lagging, here capacitor multiplier based boost converter introduced for maintain the current lagging and voltage gain. Here, the switched inductor z source inverter implemented for grid interface. Proposed z source inverter is controlled by pulse width modulation. A simplified capacitor multiplier controlled by continuous conduction mode, A detailed topology analysis and a generalized discussion are given. The multiplier boost converter has the merits of maintain voltage level and reducing cost and current lagging. Simulation results are implemented and analysis MATLAB software.

  18. Stimulated Raman clock transition without a differential ac Stark

    We considered a stimulated Raman clock transition between the ground hyperfine states of an alkali atom by using the second-order perturbation theory and the spherical tensor formalism. When the light fields are circularly polarized and properly detuned, the differential ac Stark shift of the clock transition vanishes with non-vanishing transition amplitude. With a two-zone Raman Ramsey method and a slow atomic beam, the proposed scheme should result in a clock with a systematic shift of the order of a few mHz for the case of cesium. (author)

  19. A PWM transistor inverter for an ac electric vehicle drive

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  20. Impedance Localization Measurements using AC Dipoles in the LHC

    Biancacci, Nicolo; Papotti, Giulia; Persson, Tobias; Salvant, Benoit; Tomás, Rogelio

    2016-01-01

    The knowledge of the LHC impedance is of primary importance to predict the machine performance and allow for the HL-LHC upgrade. The developed impedance model can be benchmarked with beam measurements in order to assess its validity and limit. This is routinely done, for example, moving the LHC collimator jaws and measuring the induced tune shift. In order to localize possible unknown impedance sources, the variation of phase advance with intensity between beam position monitors can be measured. In this work we will present the impedance localization measurements performed at injection in the LHC using AC dipoles as exciter as well as the underlying theory.

  1. Construction of Tunnel Diode Oscillator for AC Impedance Measurement

    Shin, J. H.; Kim, E.

    2014-03-01

    We construct a tunnel diode oscillator (TDO) to study electromagnetic response of a superconducting thin film. Highly sensitive tunnel diode oscillators allow us to detect extremely small changes in electromagnetic properties such as dielectric constant, ac magnetic susceptibility and magnetoresistance. A tunnel diode oscillator is a self-resonant oscillator of which resonance frequency is primarily determined by capacitance and inductance of a resonator. Amplitude of the signal depends on the quality factor of the resonator. The change in the impedance of the sample electromagnetic coupled to one of inductors in the resonator alters impedance of the inductor, and leads to the shift in the resonance frequency and the change of the amplitude.

  2. Total synthesis and allelopathic activity of cytosporones A-C

    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  3. Ac superconducting articles and a method for their manufacture

    A novel ac superconducting article is described comprising a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface. (auth)

  4. Aspectos acústicos do comportamento dos golfinhos

    Santos, Manuel Eduardo dos

    1989-01-01

    Este artigo pretende apresentar uma recolha bibliográfica de alguns dados e hipóteses relativos a adaptações sensoriais e comunicativas dos cetáceos, particularmente dos golfinhos. São consideradas as suas capacidades perceptivas e as potencialidades dos canais de comunicação de que dispõem, sendo realçada a sua considerável especialização na utilização do canal acústico. Depois de uma breve referência às suas capacidades auditivas concretas e às teorias explicativa...

  5. Propiedades acústicas de los paneles de carrizo

    Díaz, César

    2012-03-01

    Full Text Available Reed is a plant species very similar to common cane which is widespread all over the Earth. It is an ecological and sustainable material which is low-cost, aesthetically attractive, easy to obtain and install, and can be used in different construction systems. This work analyses the acoustic properties of reed panels from the point of view of sound absorption and sound insulation against airborne noise, according to the corresponding EN ISO standards. The experimental results obtained point to the conclusion that reed panels are suitable construction systems for controlling reverberant sound within a space, and that the sound reduction index values for different thicknesses of reed panels, or reed panels used in combination with wood particle boards, demonstrate the possibility of using them in construction as an element on the facades and roofs of buildings and for interior partitions.

    El carrizo es una especie vegetal, parecida a la caña común, que se encuentra ampliamente distribuida en la superficie terrestre. Es un material ecológico y sostenible de bajo coste, estéticamente aceptable, fácil de obtener y colocar, que permite generar diferentes sistemas constructivos. En este trabajo se analizan las propiedades acústicas de los paneles de carrizo en lo referente a la absorción acústica y al aislamiento acústico a ruido aéreo, para ello se han aplicado los procedimientos de las normas EN ISO correspondientes. De los resultados experimentales obtenidos se concluye que los paneles de carrizo son unos sistemas constructivos adecuados para el control del sonido reverberante en un recinto y que los valores del índice de reducción acústica de paneles de diferentes espesores o en combinación con tableros de partículas de madera muestran la posibilidad de utilizarlos en la edificación como elemento de fachada, en cubiertas de edificios y particiones interiores.

  6. AC Power Local Network with Multiple Power Routers

    Ryo Takahashi

    2013-12-01

    Full Text Available Controlling power flow and achieving appropriate matching between power sources and loads according to the quality of energy is expected to be one of the approaches to reduce wasted energy consumption. A power router, proposed recently, has the capability of realizing circuit switching in a power distribution network. This study focuses on the feasibility of an AC power routing network system composed of multiple power routers. To evaluate the feasibility, we experimentally confirm the circuit switching operation of the parallel and series configurations of the power routers, so that the network system can be designed by the combination of parallel and series configurations.

  7. Phonon-Induced Electron-Hole Excitation and ac Conductance in Molecular Junction

    Ueda, Akiko; Utsumi, Yasuhiro; Imamura, Hiroshi; Tokura, Yasuhiro

    2016-04-01

    We investigate the linear ac conductance of molecular junctions under a fixed dc bias voltage in the presence of an interaction between a transporting electron and a single local phonon in a molecule with energy ω0. The electron-phonon interaction is treated by the perturbation expansion. The ac conductance as a function of the ac frequency ωac decreases or increases compared with the noninteracting case depending on the magnitude of the dc bias voltage. Furthermore, a dip emerges at ωac ˜ 2ω0. The dip originates from the modification of electron-hole excitation by the ac field, which cannot be obtained by treating the phonon in the linear regime of a classical forced oscillation.

  8. Low-Cost Voltage Zero-Crossing Detector for AC-Grid Applications

    Vorobyov Maxim; Vitols Kristaps

    2014-01-01

    Renewable energy sources and energy storage devices are becoming more popular. Some of them like small hydropower turbines, wind turbines and diesel generators produce AC voltage with different frequency and voltage than the main grid. For them power electronics converters are necessary. Power electronics converters presented in industry use two or three level energy conversion, although direct AC to AC converters exist, but one of the main problems is the switch commutation when current or v...

  9. Optimizing DC Voltage Droop Settings for AC/DC System Interactions

    Eriksson, Robert; Beerten, Jef; Ghandari, Mehrdad; Belmans, Ronnie

    2014-01-01

    In this paper, a methodology is presented to optimize the dc voltage droop settings in a multiterminal voltage-source converter high-voltage direct-current system with respect to the ac system stability. Implementing dc voltage droop control enables having multiple converters assisting the system in case of a converter outage. However, the abrupt power setpoint changes create additional stress in the ac system, especially when multiple converters are connected to the same interconnected ac sy...

  10. Overexpressing mouse model demonstrates the protective role of Muc5ac in the lungs

    Ehre, Camille; Worthington, Erin N.; Liesman, Rachael M.; Grubb, Barbara R.; Barbier, Diane; O’Neal, Wanda K; Sallenave, Jean-Michel; Pickles, Raymond J.; Boucher, Richard C.

    2012-01-01

    MUC5AC, a major gel-forming mucin expressed in the lungs, is secreted at increased rates in response to infectious agents, implying that mucins exert a protective role against inhaled pathogens. However, epidemiological and pathological studies suggest that excessive mucin secretion causes airways obstruction and inflammation. To determine whether increased MUC5AC secretion alone produces airway obstruction and/or inflammation, we generated a mouse model overexpressing Muc5ac mRNA ∼20-fold in...

  11. An NPV and AC Analysis of a Stochastic Inventory System with Joint Manufacturing and Remanufacturing

    Laan, Erwin

    2000-01-01

    textabstractWhile the net present value (NPV) approach is widely accepted as the right framework for studying production and inventory control systems, average cost (AC) models are more widely used. For the well known EOQ model it can be veri_ed that (under certain conditions) the AC approach gives near optimal results. This paper investigates whether the same holds for two-source systems with joint manufacturing and remanufacturing. It appears that the performance of the AC approach stands o...

  12. Magnetic behaviour of the UCuxGey system by AC magnetic susceptibility measurements

    We have analyzed the temperature dependence of the AC susceptibility, χac(T), of UCuxGey samples (0.800≤x, y≤1.00) applying various frequencies and magnetic field strengths up to 1 T. This was done in order to verify the reentrant ferromagnetic behaviour of UCuxGe and the antiferromagnetic behaviour of UCuGey previously observed by DC susceptibility experiments. Our χac results are discussed on the basis of existing theories. (orig.)

  13. Application of AC servo motor on the in-core neutron flux instrumentation system

    The application of ac servo motor in the In-Core Neutron Flux Instrumentation System is described. The hardware component of ac servo motor control system is different from the dc motor control system. The effect of two control system on the instrumentation system is compared. The ac servo motor control system can improve the accuracy of the motion control, optimize the speed control and increase the reliability. (authors)

  14. Nonlinear dynamics of Josephson vortices in a film screen under dc and ac magnetic fields

    Sheikhzada, Ahmad; Gurevich, Alexander

    2014-01-01

    We present detailed numerical simulations of Josephson vortices in a long Josephson junction perpendicular to a thin film screen under strong dc and ac magnetic fields. By solving the sine-Gordon equation, we calculated the threshold magnetic field for penetration of fluxons as a function of frequency, and the power dissipated by oscillating fluxons as functions of the ac field amplitude and frequency. We considered the effects of superimposed ac and dc fields, and a bi-harmonic magnetic fiel...

  15. Glutathione preconditioning attenuates Ac-LDL-induced macrophage apoptosis via protein kinase C-dependent Ac-LDL trafficking.

    Rosenson-Schloss, Rene S; Chnari, Evangelia; Brieva, Thomas A; Dang, Anh; Moghe, Prabhas V

    2005-01-01

    Oxidized low-density lipoprotein (ox-LDL) incorporation into intimally resident vascular cells via scavenger receptors marks one of the early steps in atherosclerosis. Cellular apoptotic damage results from two major serial intracellular events: the binding and scavenger receptor-mediated uptake of oxidizable lipoproteins and the intracellular oxidative responses of accumulated lipoproteins. Most molecular approaches to prevent apoptotic damage have focused on singular events within the cascade of lipoprotein trafficking. To identify a multifocal strategy against LDL-induced apoptosis, we evaluated the role of cellular preconditioning by glutathione-ethyl ester (GSH-Et), a native redox regulator, in the prevention of the uptake and apoptotic effects of an oxidizable scavenger receptor-specific ligand, acetylated low-density lipoprotein (Ac-LDL). Our results indicate that GSH-Et-mediated protein kinase C (PKC) pathway modulation regulates Ac-LDL binding and incorporation into GSH-Et preconditioned cells and subsequently delays reactive oxygen intermediate generation and apoptotic conversion. The GSH-Et protective effects on apoptosis and Ac-LDL binding were reversed by calphostin C, a PKC inhibitor, and were accompanied by an increase in PKC phosphorylation. However, the rate of reactive oxygen intermediate accumulation was not increased following calphostin C treatment, suggesting that GSH-Et may play an important nonreactive oxygen-intermediate-based protective role in regulating apoptotic dynamics. Overall, we report on the novel role for GSH-Et preconditioning as a molecular strategy to limit lipoprotein entry into the cells, which presents a proactive modality to prevent cellular apoptosis in contrast with the prevalent antioxidant approaches that treat damage retroactively. PMID:15618124

  16. Current Control and Energy Balancing of a Square-Wave Powered 1AC-3AC Modular Multilevel Converter

    Schnarrenberger, Mathias; Kammerer, Felix; Gommeringer, Mario; Kolb, Johannes; Braun, Michael

    2015-01-01

    This paper presents a new control method for a Modular Multilevel Converter (MMC) fed by a push-pull converter via a medium frequency (MF) transformer. Application of this topology is a universal high-precision 3AC voltage source for a Power Hardware-in-the-Loop Emulator with a frequency range from DC up to almost the medium frequency. Advantages are high efficiency, very low harmonic distortion and high dynamics of the output voltage which can be used e.g. for simulation of electrical machin...

  17. Three-phase AC-AC power converters based on matrix converter topology matrix-reactance frequency converters concept

    Szczesniak, Pawel

    2013-01-01

    AC voltage frequency changes is one of the most important functions of solid state power converters. The most desirable features in frequency converters are the ability to generate load voltages with arbitrary amplitude and frequency, sinusoidal currents and voltages waveforms; the possibility of providing unity power factor for any load; and, finally, a simple and compact power circuit. Over the past decades, a number of different frequency converter topologies have appeared in the literature, but only the converters with either a voltage or current DC link are commonly used in industrial app

  18. Random sampling of an AC source A tool to teach probabilistic observations

    Chandi, P S; Shankar, R; Singh, R C

    2003-01-01

    An undergraduate level experiment is described to demonstrate the role of probabilistic observations in physics. A capacitor and a DC voltmeter are used to randomly sample an AC voltage source. The resulting probability distribution is analyzed to extract information about the AC source. Different characteristic probability distributions arising from various AC waveforms are calculated and experimentally measured. The reconstruction of the AC waveform is demonstrated from the measured probability distribution under certain restricted circumstances. The results are also compared with a simulated data sample. We propose this as a pedagogical tool to teach probabilistic measurements and their manipulations.

  19. Energy saving measures for automotive air conditioning (AC) system in the tropics

    Subiantoro, Alison; Ooi, Kim Tiow; Stimming, Ulrich

    2014-01-01

    Air conditioning (AC) is an integral component of modern cars in the tropics. However, AC usage in this region consumes a large amount of energy. In conventional internal combustion engine cars, it consumes up to 30% of the fuel, while in battery electric cars, AC may reduce the battery range by up to 40%. Fortunately, there are various ways to improve the efficiency of automotive ACs in the tropics. In this paper, three energy saving measures are discussed. These include a higher indoor temp...

  20. Redes de Control de la Contaminación Acústica

    Perera, P; Santiago Páez, José Salvador

    2006-01-01

    La Contaminación Acústica se concentra en las ciudades, que han crecido sin considerar el ruido como un factor determinante de la Planificación Urbana. La realidad actual, es que las ciudades son ruidosas y las administraciones tienen el deber de mejorar su calidad acústica. El primer paso para poder abordar el problema con garantías, es el conocimiento de su "realidad acústica". Los mapas acústicos son uno de los procedimientos utilizados para este cometido, pero la información que proporcio...

  1. Hybrid AC-DC offshore wind power plant topology: optimal design

    Prada Gil, Mikel de; Igualada González, Lucía; Corchero García, Cristina; Gomis Bellmunt, Oriol; Sumper, Andreas

    2015-01-01

    The aim of this paper is to present a hybrid AC-DC offshore wind power plant (OWPP) topology and to optimize its design in order to minimize the OWPP's total cost. This hybrid concept is based on clustering wind turbines and connecting each group to an AC/DC power converter installed on a collector platform which is located between the AC wind turbine array and the HVDC offshore platform. Thereby, individual power converters of each wind turbine are not required, since such AC/DC converters c...

  2. Harmonics of the AC susceptibility as probes to differentiate the various creep models

    Adesso*, M. G.; Senatore, C.; Polichetti, M.; Pace, S.

    2003-01-01

    We measured the temperature dependence of the 1st and the 3rd harmonics of the AC magnetic susceptibility on some type II superconducting samples at different AC field amplitudes, hAC. In order to interpret the measurements, we computed the harmonics of the AC susceptibility as function of the temperature T, by integrating the non-linear diffusion equation for the magnetic field with different creep models, namely the vortex glass-collective creep (single-vortex, small bundle and large bundle...

  3. Effect of AC electric fields on the stabilization of premixed bunsen flames

    Kim, Minkuk

    2011-01-01

    The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally for stoichiometric methane-air mixture by applying AC voltage to the nozzle with the single-electrode configuration. The detachment velocity either at blowoff or partial-detachment has been measured by varying the applied voltage and frequency of AC. The result showed that the detachment velocity increased with the applied AC electric fields, such that the flame could be nozzle-attached even over five times of the blowoff velocity without having electric fields. There existed four distinct regimes depending on applied AC voltage and frequency. In the low voltage regime, the threshold condition of AC electric fields was identified, below which the effect of electric fields on the detachment velocity is minimal. In the moderate voltage regime, the flame base oscillated with the frequency synchronized to AC frequency and the detachment velocity increased linearly with the applied AC voltage and nonlinearly with the frequency. In the high voltage regime, two different sub-regimes depending on AC frequency were observed. For relatively low frequency, the flame base oscillated with the applied AC frequency together with the half frequency and the variation of the detachment velocity was insensitive to the applied voltage. For relatively high frequency, the stabilization of the flame was significantly affected by the generation of streamers and the detachment velocity decreased with the applied voltage. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  4. Cabibbo-Suppressed Non-leptonic Decays of Ac and Final State Interaction

    CHEN Shao-Long; GUO Xin-Heng; LI Xue-Qian; WANG Guo-Li

    2003-01-01

    With the diquark structure of Ac, we investigate the branching ratio of Ac → nr+ and pro. The results show that without considering the final state interaction (FSI), the branching ratio of Ac → pπ0 is only of order 10-6 whereas this ratio could reach 10-4 and is at the same order as Ac → nr+ if taking into account the FSI effects. Concrete values depend on phenomenological parameters adopted in the calculations. These branching ratios can be measured in the experiments to come.

  5. Modelling of AC loss in coils made of thin tapes under DC bias current

    Pardo, Enric

    2013-01-01

    Many applications, such as magnets and SMES, are usually charged and discharged under a bias DC current, which may increase the AC loss. For their design, it is necessary to understand and predict the AC loss. This article analises the AC loss in magnet-like coils under DC bias contribution super-imposed to the AC current. The analysis is based on a numerical model that takes the interaction between magnetization currents in all turns into account. The studied example is a stack of 32 pancake...

  6. A New Approach for RRR Determination of Niobium Single Crystal Based on AC Magnetic Susceptibility

    Ermakov, Alexey; Korolev, Alexander V.; Singer, Waldemar; Singer, Xenia

    2011-03-01

    Residual resistivity ratio RRR is an important integral characteristic of material purity. It was proposed to determine the RRR on base of the AC susceptibility. AC susceptibility of a number of single crystal niobium samples of different orientations types ( , rpar; and differently treated (BCP 70, 150 μm, annealing 800° C/2h) was measured. The RRR value was determined on base of these results using a relation between the imaginary part of χ″ of AC magnetic susceptibility at low frequency, AC magnetic field and resistivity ρ of the sample.

  7. ac Stark gradient echo memory in cold atoms

    The burgeoning fields of quantum computing and quantum key distribution have created a demand for a quantum memory. The gradient echo memory scheme is a quantum memory candidate for light storage that can boast efficiencies approaching unity, as well as the flexibility to work with either two- or three-level atoms. The key to this scheme is the frequency gradient that is placed across the memory. Currently, the three-level implementation uses a Zeeman gradient and warm atoms. In this article we model an alternate gradient-creation mechanism--the ac Stark effect--to provide an improvement in the flexibility of gradient-creation and field-switching times. We propose this scheme in concert with a move to cold atoms (≅1 mK). These temperatures would increase the storage times possible, and the small ensemble volumes would enable large ac Stark shifts with reasonable laser power. We find that memory bandwidths on the order of MHz can be produced with experimentally achievable laser powers and trapping volumes, with high precision in gradient creation and switching times on the order of nanoseconds possible. By looking at the different decoherence mechanisms present in this system, we determine that coherence times on the order of tens of milliseconds are possible, as are delay-bandwidth products of approximately 50 and efficiencies over 90%.

  8. Accelerated life ac conductivity measurements of CRT oxide cathodes

    Hashim, A. A.; Barratt, D. S.; Hassan, A. K.; Nabok, A.

    2006-07-01

    The ac conductivity measurements have been carried out for the activated Ba/SrO cathode with additional 5% Ni powder for every 100 h acceleration life time at the temperature around 1125 K. The ac conductivity was studied as a function of temperature in the range 300-1200 K after conversion and activation of the cathode at 1200 K for 1 h in two cathodes face to face closed configuration. The experimental results prove that the hopping conductivity dominate in the temperature range 625-770 K through the traps of the WO 3 associate with activation energy Ea = 0.87 eV, whereas from 500-625 K it is most likely to be through the traps of the Al 2O 3 with activation energy of Ea = 1.05 eV. The hopping conductivity at the low temperature range 300-500 K is based on Ni powder link with some Ba contaminants in the oxide layer stricture which indicates very low activation energy Ea = 0.06 eV.

  9. Long-range response in ac electricity grids.

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013)EPJBFY1434-602810.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology-for example, caused by power outages or grid extensions-a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014)1951-635510.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found. PMID:27575148

  10. SOLAR TO AC POWER SOURCE FOR REMOTE AREAS USING SEIG

    MEHMET AKBABA

    2012-02-01

    Full Text Available Photovoltaic generators (PVG are increasingly used to provide electricity in remote areas. However, in many applications the DC generated electricity by a PVG need to be converted to AC. Traditionally DC to AC inverters have been widely used for this purpose. In this paper, a different system is proposed in which a self excited induction generator (SEIG driven by a permanent magnet DC motor (DCM and powered from a PVG through a maximum power point tracker (MPPT are used. A step-up chopper is utilized as an MPPT unit. The proposed system is modelled in time domain, and a detailed transient and steady-state analysis are presented. The main reason behind analyzing the system in the time domain is because of the fact that for unknown speeds, the methods developed for steady-state analysis of SEIGs can not be applied. The presented work shows that the full available power of the PVG can be harnessed by selecting suitable values for the duty cycle and the frequency of the step up chopper and the excitation capacitor of the SEIG. It is also shown that with such a combination power utilization efficiency of more than 83% can be achieved.

  11. Perfecting the Photometric Calibration of the ACS CCD Cameras

    Bohlin, Ralph C

    2016-01-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the CCD cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1\\% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC\\footnote{http://www.stsci.edu/hst/observatory/crds/calspec.html} database for three primary hot 30,000--60,000K WDs define the sensitivity calibrations for the WFC and HRC filters. The external uncertainty for the absolute flux is $\\sim$1\\%, while the internal consistency of the sensitivities in the broadband ACS filters is $\\sim$0.3\\% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1\\% at the WFC1-1K subarray position, which achieves the 1\\% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1\\% precision goal is achieved over the full ...

  12. Perfecting the Photometric Calibration of the ACS CCD Cameras

    Bohlin, Ralph C.

    2016-09-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the charge-coupled device cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC1 database for three primary hot 30,000–60,000K WDs define the sensitivity calibrations for the Wide Field Channel (WFC) and High Resolution Channel (HRC) filters. The external uncertainty for the absolute flux is ˜1%, while the internal consistency of the sensitivities in the broadband ACS filters is ˜0.3% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1% at the WFC1-1K subarray position, which achieves the 1% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1% precision goal is achieved over the full F814W WFC field of view for stars of K type and hotter. New encircled energies and absolute sensitivities replace the seminal results of Sirianni et al. that were published in 2005. After implementing the throughput updates, synthetic predictions of the WFC and HRC count rates for the average of the three primary WD standard stars agree with the observations to 0.1%.

  13. SQUIDs De-fluxing Using a Decaying AC Magnetic Field

    Matlashov, Andrei Nikolaevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Semenov, Vasili Kirilovich [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Anderson, Bill [Senior Scientific, LLC, Albuquerque, NM (United States)

    2016-06-08

    Flux trapping is the Achilles’ heel of all superconductor electronics. The most direct way to avoid flux trapping is a prevention of superconductor circuits from exposure to magnetic fields. Unfortunately this is not feasible if the circuits must be exposed to a strong DC magnetic field even for a short period of time. For example, such unavoidable exposures take place in superparamagnetic relaxation measurements (SPMR) and ultra-low field magnetic resonance imaging (ULF MRI) using unshielded thin-film SQUID-based gradiometers. Unshielded SQUIDs stop working after being exposed to DC magnetic fields of only a few Gauss in strength. In this paper we present experimental results with de-fluxing of planar thin-film LTS SQUID-based gradiometers using a strong decaying AC magnetic field. We used four commercial G136 gradiometers for SPMR measurements with up to a 10 mT magnetizing field. Strong 12.9 kHz decaying magnetic field pulses reliably return SQUIDs to normal operation 50 ms after zeroing the DC magnetizing field. This new AC de-fluxing method was also successfully tested with seven other different types of LTS SQUID sensors and has been shown to dissipate extremely low energy.

  14. Memory Convergence and Optimization with Fuzzy PSO and ACS

    Subhash C. Pandey

    2008-01-01

    Full Text Available Associative neural memories are models of biological phenomena that allow for the storage of pattern associations and the retrieval of the desired output pattern upon presentation of a possibly noisy or incomplete version of an input pattern. In this study, we introduce fuzzy swarm particle optimization technique for convergence of associative neural memories based on fuzzy set theory. A Fuzzy Particle Swarm Optimization (FPSO consists of clustering of swarm's particle by applying fuzzy c-mean algorithm to attain the neighborhood best. We present a singular value decomposition method for the selection of efficient rule from a given rule base required to attain the global best. Finally, we illustrate the proposed method by virtue of some examples. Further, ant colony system ACS algorithm is used to study the Symmetric Traveling Salesman Problem TSP. The optimum parameters for this algorithm have to found by trial and error. The ACS parameters working in a designed subset of TSP instances has also been optimized by virtue of Particle Swarm Optimization PSO.

  15. AcMNPV As A Model for Baculovirus DNA Replication

    Eric B. Carstens

    2009-01-01

    Baculoviruses were first identified as insect-specific pathogens, and it was this specificity that lead to their use as safe, target specific biological pesticides. For the past 30 years, AcMNPV has served as the subject of intense basic molecular research into the baculovirus infectious cycle including the interaction of the virus with a continuous insect cell line derived from Spodoptera frugiperda. The studies on baculoviruese have led to an in-depth understanding of the physical organization of the viral genomes including many complete genomic sequences, the time course of gene expression, and the application of this basic research to the use of baculoviruses not only as insecticides, but also as a universal eukaryotic protein expression system, and a potential vector in gene therapy. A great deal has also been discovered about the viral genes required for the replication of the baculovirus genome, while much remains to be learned about the mechanism of viral DNA replication. This report outlines the current knowledge of the factors involved in baculovirus DNA replication, using data on AcMNPV as a model for most members of the Baculoviridae.

  16. Resonant tunneling of interacting electrons in an AC electric field

    The problem of the effect of electron-electron interaction on the static and dynamic properties of a double-barrier nanostructure (resonant tunneling diode (RTD)) is studied in terms of a coherent tunneling model, which includes a set of Schrödinger and Poisson equations with open boundary conditions. Explicit analytical expressions are derived for dc and ac potentials and reduced (active and reactive) currents in the quasi-classical approximation over a wide frequency range. These expressions are used to analyze the frequency characteristics of RTD. It is shown that the interaction can radically change the form of these expressions, especially in the case of a hysteretic I-V characteristic. In this case, the active current and the ac potentials can increase sharply at both low and high frequencies. For this increase to occur, it is necessary to meet quantum regime conditions and to choose a proper working point in the I-V characteristic of RTD. The possibility of appearance of specific plasma oscillations, which can improve the high-frequency characteristics of RTD, is predicted. It is found that the active current can be comparable with the resonant dc current of RTD

  17. Resonant tunneling of interacting electrons in an AC electric field

    Elesin, V. F., E-mail: VFElesin@mephi.ru [National Research Nuclear University MEPhI (Russian Federation)

    2013-11-15

    The problem of the effect of electron-electron interaction on the static and dynamic properties of a double-barrier nanostructure (resonant tunneling diode (RTD)) is studied in terms of a coherent tunneling model, which includes a set of Schrödinger and Poisson equations with open boundary conditions. Explicit analytical expressions are derived for dc and ac potentials and reduced (active and reactive) currents in the quasi-classical approximation over a wide frequency range. These expressions are used to analyze the frequency characteristics of RTD. It is shown that the interaction can radically change the form of these expressions, especially in the case of a hysteretic I-V characteristic. In this case, the active current and the ac potentials can increase sharply at both low and high frequencies. For this increase to occur, it is necessary to meet quantum regime conditions and to choose a proper working point in the I-V characteristic of RTD. The possibility of appearance of specific plasma oscillations, which can improve the high-frequency characteristics of RTD, is predicted. It is found that the active current can be comparable with the resonant dc current of RTD.

  18. AcEST(EST sequences of Adiantum capillus-veneris and their annotation) - AcEST | LSDB Archive [Life Science Database Archive metadata

    Full Text Available AcEST AcEST(EST sequences of Adiantum capillus-veneris and their annotation) Data detail Data name AcEST(EST... sequences of Adiantum capillus-veneris and their annotation) Description of data contents EST sequence of Adiantum capi...db/view/archive_acest#en Data acquisition method Capillary sequencer Data analysi...atabases) Number of data entries Adiantum capillus-veneris ESTs: 30,540. Data item Description Clone id Clon...e ID of EST sequence of Adiantum capillus-veneris. Library Library name Length Nu

  19. La crisis del siglo XII A.C. pueblos del mar y guerra de Troya ca. 1215-1175 A.C.

    Mederos Martín, Alfredo

    2007-01-01

    Los ataques de los Pueblos del Mar se produjeron en dos momentos diferentes, separados por 32 años, ca. 1208 y ca. 1176 a.C., y fueron efectos colaterales de las crisis de dos grandes estados, primero Ahhiyawa y posteriormente Hatti. Esta fase de inestabilidad se generalizó en el Mediterráneo Oriental a partir de la muerte de Ramses II ca. 1213 a.C. y Tudhaliya IV, ca. 1215/1209 a.C., en la cual las tensiones internas dentro de Hatti y Egipto, por los problemas sucesorios, tuvieron una import...

  20. Mathematical modeling of Automatic Control System (ACS) and synchronous motor in high reliability power supply systems in Kozloduy NPP - set up optimization of ACS

    The article presents the models of Automatic Control System (ACS) and synchronous motor of the reversible generator-engine groups of the first category power supply section in the Kozloduy NPP units 1 to 4. The control parameter is the magnetic field. The research aims are optimal ACS setups, property control guaranties in accordance with the technical requirements. The used synchronous machine model is included in Matlab5.x library. For optimization the instruments of optimization toolbox - NCD out port block and plant actuator and created basic models of variable Discrete PID-regulator and PWM system are utilized. The results are applied for the setup of the real ACS. The results precision of the created models gives a possibility for a real summary model development and the achieved models implementation in cases of fluctuations of AC/DC reversible electromechanical supply

  1. Mathematical modeling of Automatic Control System (ACS) and synchronous generator in high reliability power supply systems in Kozloduy NPP - set up optimization of ACS

    The article presents the models of Automatic Control System (ACS) and synchronous generator of the reversible generator-engine groups of first category power supply section in the Kozloduy NPP units 1 to 4. The control parameter is the synchronous machine tension. The research aims are optimal ACS setups, property control guaranties in accordance with the technical requirements. The used synchronous machine model is included in Matlab5.x library. For optimization the instruments of optimization toolbox - NCD out port block and plant actuator and created basic models of variable Discrete PID-regulator and PWM system are utilized. The results are applied for the setup of the real ACS. The results precision of the created models gives a possibility for a real summary model development and the achieved models implementation in cases of fluctuations of AC/DC reversible electromechanical supply

  2. Intégration fonctionnelle autour des composants quatre quadrants
    Avec l'application à la conversion AC/AC

    Nguyen, Dac-Binh

    2008-01-01

    La thèse porte sur l'intégration fonctionnelle autour des composants commandables bidirectionnels en courant et en tension, avec pour application, la conversion AC-AC à prélèvement sinusoïdal (PFC). La première partie du document de thèse présente la mise en oeuvre d'un gradateur AC-AC à l'aide de dispositifs intégrables. Certains bénéfices sont clairement mis en évidence à travers une analyse fonctionnelle et une validation expérimentale complètes. La seconde partie du mémoire porte sur l'in...

  3. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Kajikawa, K., E-mail: kajikawa@sc.kyushu-u.ac.j [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Funaki, K. [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Shikimachi, K.; Hirano, N.; Nagaya, S. [Chubu Electric Power Co., Inc., 20-1 Kitasekiyama, Ohdaka-cho, Midori-ku, Nagoya 459-8522 (Japan)

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean's critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  4. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean’s critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  5. AC impedance studies of V2O5 containing glasses

    Glasses with composition V2O5-BaO-MO-B2O3(MO=SiO2,GeO2,P2O5) were studied using AC impedance analyzer. The measurements show that conductivities increase with V2O5 contents, and the P2O5 containing glasses have higher conductivities. The electric modulus was analyzed based on the Kohlrausch-Williams-Watts (KWW) relaxation function, φ(t)=exp[-(t/τ0)1-n]. The exponent n increases with V2O5 content. In addition, as the temperature approaches glass transition temperature, n increases with temperature. The results are interpreted in terms of Ngai's coupling model when applied to polaron conductivity relaxation

  6. Team-oriented Adaptive Droop Control for Autonomous AC Microgrids

    Shafiee, Qobad; Nasirian, Vahidreza; Guerrero, Josep M.; L. Lewis, Frank; Davoudi, Ali

    2014-01-01

    This paper proposes a distributed control strategy for voltage and reactive power regulation in ac Microgrids. First, the control module introduces a voltage regulator that maintains the average voltage of the system on the rated value, keeping all bus voltages within an acceptable range. Dynamic...... regulator, dynamically fine-tunes the Q-E coefficients to handle the proportional reactive power sharing. Accordingly, locally supplied reactive power of any source is compared with neighbor sources and the local droop coefficient is adjusted to mitigate and, ultimately, eliminate the load mismatch. The...... proposed controllers are fully distributed; i.e., each source requires information exchange with only a few other sources, those in direct contact through the communication infrastructure. A Microgrid test bench is used to verify the proposed controlmethodology, where different test scenarios such as load...

  7. Experimental investigation of a.c. losses in cabled superconductors

    A.c. losses in multifilamentary composite superconducting strands and cables have been measured in adiabatic conditions for transverse field sweep rates up to 50 T s-1. Measurements were performed on NbTi and Nb3Sn conductors of several configurations and surface preparations: single strands, soldered strands and cables of varying degrees of compaction composed of bare strands, with CuNi barriers and strands with chrome plating. The experimental data agree well with existing loss models. The data suggests that the total cable loss grows as approx.= 1/(void)3 below void fractions of 40%. This observed cable loss dependence on void fraction does not agree well with a previously proposed model. (author)

  8. Dc and ac Josephson effects in a granular material

    This paper reports on three-dimensional systems of point contacts that were prepared by pressing together Niobium grains of about 100 μm diameter inside a sapphire cylinder. Current-voltage characteristics were studied in dependence of temperature and, in addition, of the power of incident microwaves (X-bank). The results are similar to those established for a single weak link junction. Only for small currents the sample showed different behavior. The inverse a.c. Josephson effect was observed. The measured d.c. voltage shows and alternating temperature dependence which might be expected following the calculations of J.J. Chang for a weak link of small capacity and small resistance

  9. Modelado acústico de silenciadores con material absorbente

    TORRES PICAZO, MARÍA ISABEL

    2008-01-01

    Esta Tesis se centra en el desarrollo e implementación de métodos para el diseño y modelado acústico de silenciadores de motores de combustión interna, a través de herramientas basadas en soluciones analíticas y numéricas de la ecuación de ondas. La necesidad de técnicas de diseño que proporcionen rápida y eficazmente resultados precisos incluso a altas frecuencias ha aumentando con el tiempo, debido a que el ruido de los vehículos se ha convertido en una fuente importante de contaminación am...

  10. Soliton ratchetlike dynamics by ac forces with harmonic mixing

    Salerno, Mario; Zolotaryuk, Yaroslav

    2002-01-01

    The possibility of unidirectional motion of a kink (topological soliton) of a dissipative sine-Gordon equation in the presence of ac forces with harmonic mixing (at least biharmonic) and of zero mean, is presented. The dependence of the kink mean velocity on system parameters is investigated...... numerically and the results are compared with a perturbation analysis based on a point-particle representation of the soliton. We find that first order perturbative calculations lead to incomplete descriptions, due to the important role played by the soliton-phonon interaction in establishing the phenomenon...... mechanism, while for biharmonic drivers with even harmonic superposition, also a point-particle contribution to the drift velocity is present. The phenomenon is robust enough to survive the presence of thermal noise in the system and can lead to several interesting physical applications....

  11. Resistojet control and power for high frequency ac buses

    Gruber, Robert P.

    1987-01-01

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.

  12. A new LTPS TFT AC pixel circuit for an AMOLED

    This work presents a new voltage programmed pixel circuit for an active-matrix organic light-emitting diode (AMOLED) display. The proposed pixel circuit consists of six low temperature polycrystalline silicon thin-film transistors (LTPS TFTs), one storage capacitor, and one OLED, and is verified by simulation work using HSPICE software. Besides effectively compensating for the threshold voltage variation of the driving TFT and OLED, the proposed pixel circuit offers an AC driving mode for the OLED, which can suppress the degradation of the OLED. Moreover, a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period. (semiconductor integrated circuits)

  13. A new LTPS TFT AC pixel circuit for an AMOLED

    Zhang Yongwen; Chen Wenbin

    2013-01-01

    This work presents a new voltage programmed pixel circuit for an active-matrix organic light-emitting diode (AMOLED) display.The proposed pixel circuit consists of six low temperature polycrystalline silicon thin-film transistors (LTPS TFTs),one storage capacitor,and one OLED,and is verified by simulation work using HSPICE software.Besides effectively compensating for the threshold voltage variation of the driving TFT and OLED,the proposed pixel circuit offers an AC driving mode for the OLED,which can suppress the degradation of the OLED.Moreover,a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.

  14. Democracy against Nationalism. The A.C. Popovici Case

    Gelu SABĂU

    2013-03-01

    Full Text Available This article seeks out to analyze the critique of democracy in Romania during the first half of the twentieth century. The starting point of this analysis is the opposition between nationalism and democracy theorized by the Romanian political scientist Aurel C. Popovici. We can find the origin of A. C. Popovici’s conception in Eminescu’s critical attitude towards modern society and French liberalism. A.C. Popovici emphasizes the irreducible opposition between democracy, which is global and universal, and nationalism, which has the capacity to underline the cultural specificity of every nation. I will try to compare the way in which Popovici refers to democracy and nationalism with the approach of this ratio in Western societies (England or France.

  15. Engineering Design of the ITER AC/DC Power Supplies

    To design high power pulse power supplies, especially in huge power supplies have not designed till now, it is necessary to analyze a system's characteristics and relations with another systems as well as to know high voltage, high current control technologies. Contents of this project are; - Study for the engineering designs changed recently by ITER Organization(IO) and writing specifications for the power supplies to reduce project risk. - Detailed analysis of the AC/DC Converters and writing subtask reports on the Task Agreement. - Study for thyristor numbers, DCR's specifications for Korea-China sharing meetings. - Study for the grounding systems of the ITER power supply system. The results may used as one of reference for practical designs of the high power coil power supplies and also may used in various field such as electroplating, plasma arc furnaces, electric furnaces

  16. AC-ELECTROKINETICS BASED TOOLS IN NANOENGINEERING AND MOLECULAR ELECTRONICS

    R. Durán

    2005-08-01

    Full Text Available Slllcon-based mlcroeledronics has been following the integration prognosls of MOORE's Law durlng the past decades and posslbly will do so for another decade or two. Physlcal, technological and also flnancialllmlts In the foreseeable future will slow down the contlnued expansiOn of this branch of mlcroeledronlcs and instead wlll force a new technological approach based on molecular-scale eledronics (MOLETRONICS. New tools are needed to allow molecular devlce manufaduring and nanoscale engineering with hlgh precision and produdivlty. One group of methods with the potentlal for use In such a manufaduring process Is based on a.c. eledrokinetlcs effeds, which are descrlbed and discussed in this paper.

  17. Measurement of AC losses in different former materials

    Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa;

    1998-01-01

    A high temperature superconducting cable may be based on a centrally located cylindrical support, a so-called former. If electrically conductive, the former can contribute to the AC losses through eddy current losses caused by unbalanced axial and tangential magnetic fields. With these measurements...... we aim at investigating the eddy current losses of commonly used former materials. A one layer cable conductor was wound on a glass fibre reinforced polymer (GRFP) former. By inserting a variety of materials into this, it was possible to measure the eddy current losses of each of the former...... candidates separately; for example copper tubes, stainless steel braid, copper braid, corrugated stainless steel tubes, etc. The measured data are compared with the predictions of a theoretical model. Our results show that in most cases, the losses induced by eddy currents in the former are negligible...

  18. The AC magnetic susceptibility of high temperature superconductors

    Salim, M

    2001-01-01

    This research concerns the development of AC magnetic susceptometers and use of susceptometers in analysing high temperature superconductors. Two of the designs were a differential magnetic susceptometer (DMS) and a double coil screening susceptometer (DCSS) whose descriptions are given in detail including coil design, field measurements, susceptometer operation, experimental instrumentation, phase adjustment, susceptometer calibration and sensitivity for each design. Theoretical details are given regarding each design in order to calculate the complex external and internal susceptibility. Investigation concerning the demagnetisation factor of different geometries, and the significant features and limitation for each design are also provided. The susceptometers were applied to a wide range of YBCO samples, which includes bulk samples with different geometry (i.e. Slabs, disk, powder and thick film) and thin films with different oxygen contents. Several silver sheathed Bi-2223 tapes were also involved. This al...

  19. Measurement of AC losses in different former materials

    Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa;

    1998-01-01

    candidates separately; for example copper tubes, stainless steel braid, copper braid, corrugated stainless steel tubes, etc. The measured data are compared with the predictions of a theoretical model. Our results show that in most cases, the losses induced by eddy currents in the former are negligible......A high temperature superconducting cable may be based on a centrally located cylindrical support, a so-called former. If electrically conductive, the former can contribute to the AC losses through eddy current losses caused by unbalanced axial and tangential magnetic fields. With these measurements...... we aim at investigating the eddy current losses of commonly used former materials. A one layer cable conductor was wound on a glass fibre reinforced polymer (GRFP) former. By inserting a variety of materials into this, it was possible to measure the eddy current losses of each of the former...

  20. An AC electric trap for ground-state molecules

    van Veldhoven, J; Meijer, G; Veldhoven, Jacqueline van; Bethlem, Hendrick L.; Meijer, Gerard

    2005-01-01

    We here report on the realization of an electrodynamic trap, capable of trapping neutral atoms and molecules in both low-field and high-field seeking states. Confinement in three dimensions is achieved by switching between two electric field configurations that have a saddle-point at the center of the trap, i.e., by alternating a focusing and a defocusing force in each direction. AC trapping of 15ND3 molecules is experimentally demonstrated, and the stability of the trap is studied as a function of the switching frequency. A 1 mK sample of 15ND3 molecules in the high-field seeking component of the |J,K>=|1,1> level, the ground-state of para-ammonia, is trapped in a volume of about 1 mm^3.

  1. FLUXCAP: A flux-coupled ac/dc magnetizing device

    Gopman, Daniel B; Kent, Andrew D

    2012-01-01

    We report on an instrument for applying ac and dc magnetic fields by capturing the flux from a rotating permanent magnet and projecting it between two adjustable pole pieces. This can be an alternative to standard electromagnets for experiments with small samples or in probe stations in which an applied magnetic field is needed locally, with advantages that include a compact form-factor, very low power requirements and dissipation as well as fast field sweep rates. This flux capture instrument (FLUXCAP) can produce fields from -400 to +400 mT, with field resolution less than 1 mT. It generates static magnetic fields as well as ramped fields, with ramping rates as high as 10 T/s. We demonstrate the use of this apparatus for studying the magnetotransport properties of spin-valve nanopillars, a nanoscale device that exhibits giant magnetoresistance.

  2. AC motor controller with 180 degree conductive switches

    Oximberg, Carol A. (Inventor)

    1995-01-01

    An ac motor controller is operated by a modified time-switching scheme where the switches of the inverter are on for electrical-phase-and-rotation intervals of 180.degree. as opposed to the conventional 120.degree.. The motor is provided with three-phase drive windings, a power inverter for power supplied from a dc power source consisting of six switches, and a motor controller which controls the current controlled switches in voltage-fed mode. During full power, each switch is gated continuously for three successive intervals of 60.degree. and modulated for only one of said intervals. Thus, during each 60.degree. interval, the two switches with like signs are on continuously and the switch with the opposite sign is modulated.

  3. The ACS LCID Project: overview and first results

    Gallart, Carme

    2007-01-01

    The star formation history (SFH) of Local Group galaxies is a powerful tool for studying their evolution, including chemical enrichment histories and stellar population gradients, which in turn may shed light on the role of reionization or Supernovae feedback in galaxy formation and evolution. In particular, isolated dwarfs are ideal laboratories since their evolution has not been complicated by the vicinity of giant galaxies. In this paper, we present the project Local Cosmology from Isolated Dwarfs (LCID), aimed at deriving detailed SFHs for a sample of Local Group isolated dwarf galaxies. To accomplish this goal we have collected, using the ACS on board the HST, color-magnitude diagrams (CMD) reaching their oldest main sequence turnoff (V~28 or M_V~+3.5) with good photometric accuracy. Some preliminary results from the CMDs are shown and briefly discussed.

  4. Coherent Spin Polarization in an AC-Driven Mesoscopic Device

    Asham M. D.

    2012-01-01

    Full Text Available The spin transport characteristics through a mesoscopic device are investigated under the effect of an AC-field. This device consists of two-diluted magnetic semiconductor (DMS leads and a nonmagnetic semiconducting quantum dot. The conductance for both spin parallel and antiparallel alignment in the two DMS leads is deduced. The corresponding equations for giant magnetoresistance (GMR and spin polarization (SP are also deduced. Calculations show an oscillatory behavior of the present studied pa- rameters. These oscillations are due to the coupling of photon energy and spin-up & spin-down subbands and also due to Fano-resonance. This research work is very im- portant for spintronic devices.

  5. Dicty_cDB: FCL-AC28 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC28 (Link to dictyBase) - G03268 DDB0233386 Contig-U16045-1 FCL-AC28P ... t virus n gene for nucleocapsid protein, isolate 8-Hip ... 96-12, genomic RNA. 42 3e-05 2 AJ418779 |AJ418779. ...

  6. Update History of This Database - AcEST | LSDB Archive [Life Science Database Archive metadata

    Full Text Available [ Credits ] BLAST Search Image Search Home About Archive Update History Contact us AcEST Update History...iew/acest/ ) is released. Joomla SEF URLs by Artio About This Database Database Description Download License Update History... of This Database Site Policy | Contact Us Update History of This Database - AcEST | LSDB Archive ...

  7. Bioacústica de fondos marinos. Acústica aplicada a la pesca

    Carbó, Rafael; Molero, Adriana C.; Camarasa, M.; J.I. Linares

    2000-01-01

    PACS: 43.80.Ev, 43.30.Sf.-- Publicado en el Vol. XXXI, núm. 3-4, tercer y cuarto trimestre 2000 de la Revista de Acústica: Número especial dedicado al XXV Aniversario del Instituto de Acústica del C.S.I.C.

  8. Autographa californica multiple nucleopolyhedrovirus ac53 plays a role in nucleocapsid assembly

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf53 (ac53) is a highly conserved gene existing in all sequenced Lepidoptera and Hymenoptera baculoviruses, but its function remains unknown. To investigate its role in the baculovirus life cycle, an ac53 deletion virus (vAcac53KO-PH-GFP) was generated through homologous recombination in Escherichia coli. Fluorescence and light microscopy and titration analysis revealed that vAcac53KO-PH-GFP could not produce infectious budded virus in infected Sf9 cells. Real-time PCR demonstrated that the ac53 deletion did not affect the levels of viral DNA replication. Electron microscopy showed that many lucent tubular shells devoid of the nucleoprotein core are present in the virogenic stroma and ring zone, indicating that the ac53 knockout affected nucleocapsid assembly. With a recombinant virus expressing an Ac53-GFP fusion protein, we observed that Ac53 was distributed within the cytoplasm and nucleus at 24 h post-infection, but afterwards accumulated predominantly near the nucleus-cytoplasm boundary. These data demonstrate that ac53 is involved in nucleocapsid assembly and is an essential gene for virus production

  9. AC Losses and Their Thermal Effect in High-Temperature Superconducting Machines

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan;

    2016-01-01

    approximation and solves the H formulation. Afterward, the computed ac losses are considered as the heat source in a thermal model to study the temperature profile in HTS windings. The method proposed is able to evaluate ac losses and their thermal effect, thus providing a reference to design an HTS machine and...

  10. AC Losses and Their Thermal Effect in High Temperature Superconducting Machines

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan;

    2015-01-01

    homogeneous approximation and solves the H formulation. Afterwards, the computed AC losses are considered as the heat source in a thermal model to study the temperature profile in HTS windings. The method proposed is able to evaluate AC losses and their thermal effect, thus providing a reference to design an...

  11. Complex study of transport AC loss in various 2G HTS racetrack coils

    Chen, Yiran, E-mail: yc315@cam.ac.uk [University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Zhang, Min; Chudy, Michal; Matsuda, Koichi; Coombs, Tim [University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

    2013-04-15

    Highlights: ► Comparing transport AC losses of two types of 2G HTS racetrack coils. ► The magnetic substrate in the MAG RABITS coil is the main difference. ► Experimental data agree well with simulation results. ► The transport AC loss in the MAG RABITS coil is 36% higher than that in the IBAD coil. ► It is better to keep all the substrate non-magnetic. -- Abstract: HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance.

  12. Strain effects on the AC critical current of Bi-2223 superconducting tapes

    Axial tensile strains effects on the AC critical current of Bi-2223/Ag and Bi-2223/AgMn tapes produced by the powder-in-tube method have been studied, at 77 K. 5 μV/cm field criterion was used to determine the AC and DC critical current. The degradation of AC critical current due to axial tensile strain is irreversible, the normalized AC and DC critical current Icn vs tensile strain ε curves Icn(ε) of Ag and AgMn/Ag sheathed Bi-2223 superconducting composite tapes are almost the same when the axial tensile strain is less than ε0.9, when the axial tensile strain is larger than ε0.9, the AC critical current Icn decrease less rapidly than DC critical current Icn, and at the same strain, the normalized AC critical current is greater than normalized DC critical current. This may be due to the greater relative increment in DC voltage than in AC voltage when the strain is large enough to deteriorate the transport capacity of the tape. The AC and DC Icn(ε) curves have the same empirical formula as Icn=1-(ε/a)b, where a and b are constants

  13. An NPV and AC Analysis of a Stochastic Inventory System with Joint Manufacturing and Remanufacturing

    E.A. van der Laan (Erwin)

    2000-01-01

    textabstractWhile the net present value (NPV) approach is widely accepted as the right framework for studying production and inventory control systems, average cost (AC) models are more widely used. For the well known EOQ model it can be veri_ed that (under certain conditions) the AC approach gives

  14. Performance Analysis of Phase Controlled Unidirectional and Bidirectional AC Voltage Controllers

    Abdul Sattar Larik

    2011-01-01

    Full Text Available AC voltage controllers are used to vary the output ac voltage from a fixed ac input source. They are also commonly called ac voltage regulators or ac choppers. The output voltage is either controlled by PAC (Phase Angle Control method or on-off control method. Due to various advantages of ac voltage controllers, such as high efficiency, simplicity, low cost and ability to control large amount of power they efficiently control the speed of ac motors, light dimming and industrial heating, etc. These converters are variable structure systems and generate harmonics during the operation which will affect the power quality when connected to system network. During the last couple of years, a number of new semiconductor devices and various power electronic converters has been introduced. Accordingly the subject of harmonics and its problems are of great concern to power industry and customers. In this research work, initially the simulation models of single phase unidirectional and bidirectional ac voltage controllers were developed by using MATLAB software. The harmonics of these models are investigated by simulation. In the end, the harmonics were also analyzed experimentally. The simulated as well as experimental results are presented.

  15. Nuclear Structure Effects in the Exotic Decay of $^{225}$Ac via $^{14}$C Emission

    2002-01-01

    % IS323 \\\\ \\\\ We propose to build at Isolde a high intensity $^{225}$Ac source by $\\beta$-decay of $^{225}$(Ra+Fr) beam, to be used at the superconducting spectrometer SOLENO of IPN-Orsay in order to study a possible fine structure in the spectrum of $^{14}$C ions spontaneously emitted by $^{225}$Ac.

  16. Investigations on gradient a.c. conductivity characteristics of bamboo (Dendrocalamus strictus)

    Navin Chand; Deepak Jain; Archana Nigrawal

    2006-04-01

    Effect of temperature and frequency variation on a.c. conductivity of bamboo was determined by using a 4274 A Multi-Frequencies LCR meter. Electrical measurements were carried out in the temperature range 24–120°C and in the frequency range 4–100 kHz. It was observed that the a.c. conductivity increased initially and then decreased with increase of temperature and frequencies. The increase of distance from outer surface to the inner surface side increased the a.c. conductivity values and showed the grading in a.c. conductivity behaviour. Two phases of a.c. conductivity behaviour with temperature exist in bamboo. At 10 mm distance a.c. conductivity suddenly increases which is the critical depth from skin for this bamboo. Increase of temperature, at all the frequencies increases the a.c. conductivity initially and then decreases. Downward peaks in a.c. conductivities are observed at all the frequencies due to the presence of moisture in bamboo, which liberated on heating. Sharp peak is observed in case of sample 4, which is inner most strip. Maximum sharp peak is observed at lowest 4 kHz frequency.

  17. Aglomeración acústica de partículas

    Gallego Juárez, Juan Antonio; Rodríguez, Germán; Riera, Enrique; Gaete Garretón, Luis; Andrés Gallego, Eduardo; Montoya Vitini, Fausto; Elvira Segura, Luis; Hoffmann, Thomas L.; Vázquez, F.; Gálvez, J. C.; González Gómez, Icíar; Piñuel, L.; García Fernández, J. A.; Acosta Aparicio, Víctor Manuel

    2000-01-01

    PACS: 43.35, 43.25.-- Publicado en el Vol. XXXI, núm. 3-4, tercer y cuarto trimestre 2000 de la Revista de Acústica: Número especial dedicado al XXV Aniversario del Instituto de Acústica del C.S.I.C.

  18. ACCE/ACS National Educator and Leader of the Year Winners: AEC Congratulates These Outstanding Educators

    Australian Educational Computing, 2012

    2012-01-01

    This article presents the ACCE/ACS National Educator and Leader of the Year winners. Anne Mirtschin is the recipient of the ACCE/ACS 2012 Educator of the Year Award. Mirtschin is an innovative teacher at Hawkesdale P-12 College a small rural school that is isolated culturally and geographically. She uses online tools and technology to create…

  19. Dicty_cDB: FC-AC14 [Dicty_cDB

    Full Text Available FC (Link to library) FC-AC14 (Link to dictyBase) - - - Contig-U15335-1 FC-AC14F (Link to Origina ... **nciip*tns*s*g*g*s tndcrw*qmrfgi*ssshnw*rsrfskilr*sip *nlcqdscqr*gsflftrt*nqkrpq g*l*trkrqeeetikslysf--- ...

  20. Single phase AC-DC power factor corrected converter with high frequency isolation using buck converter

    R. Ramesh,

    2014-03-01

    Full Text Available Single phase ac-dc converters having high frequency isolation are implemented in buck, boost, buck-boost configuration with improving the power quality in terms of reducing the harmonics of input current. The paperpropose the circuit configuration, control mechanism, and simulation result for the single phase ac-dc converter.

  1. Binding of Bacillus thuringiensis toxin CrylAc to multiple sites of cadherin in pink bollworm

    Toxins from Bacillus thuringiensis (Bt) are widely used for pest control. In particular, Bt toxin Cry lAc produced by transgenic cotton kills some key lepidopteran pests. We found that CrylAc binds to recombinant peptides corresponding to extracellular regions of a cadherin protein (BtR) in a major ...

  2. Recovery of consciousness in broilers following combined dc and ac stunning

    Broilers in the United States are typically electrically stunned using low voltage-high frequency pulsed DC water bath stunners and in the European Union broilers are electrocuted using high voltage-low frequency AC. DC stunned broilers regain consciousness in the absence of exsanguination and AC st...

  3. AC loss measurements in HTS coil assemblies with hybrid coil structures

    Jiang, Zhenan; Long, Nicholas J.; Staines, Mike; Badcock, Rodney A.; Bumby, Chris W.; Buckley, Robert G.; Amemiya, Naoyuki

    2016-09-01

    Both AC loss and wire cost in coil windings are critical factors for high temperature superconductor (HTS) AC machinery applications. We present AC loss measurement results in three HTS coil assemblies at 77 K and 65 K which have a hybrid coil structure comprising one central winding (CW) and two end windings (EWs) wound with ReBCO and BSCCO wires with different self-field I c values at 77 K. All AC loss results in the coil assemblies are hysteretic and the normalized AC losses in the coil assemblies at different temperatures can be scaled with the I c value of the coil assemblies. The normalised results show that AC loss in a coil assembly with BSCCO CW can be reduced by using EWs wound with high I c ReBCO wires, whilst further AC loss reduction can be achieved by replacing the BSCCO CW with ReBCO CW. The results imply that a flexible hybrid coil structure is possible which considers both AC loss and wire cost in coil assemblies.

  4. Analysis of AC loss in superconducting power devices calculated from short sample data

    Rabbers, J.J.; Haken, ten B.; Kate, ten H.H.J.

    2003-01-01

    A method to calculate the AC loss of superconducting power devices from the measured AC loss of a short sample is developed. In coils and cables the magnetic field varies spatially. The position dependent field vector is calculated assuming a homogeneous current distribution. From this field profile

  5. Vector control of three-phase AC machines system development in the practice

    Quang, Nguyen Phung

    2008-01-01

    Covers the area of vector control of 3-phase AC machines, in particular induction motors with squirrel-cage rotor, permanent excited synchronous motors and doubly-fed induction machines. This title summarizes the basic structure of a field-oriented controlled 3-phase AC drive and grid voltage orientated controlled wind power plant.

  6. Spectroscopic AC Susceptibility Imaging (sASI) of Magnetic Nanoparticles

    Ficko, Bradley W.; Nadar, Priyanka M.; Diamond, Solomon G.

    2014-01-01

    This study demonstrates a method for alternating current (AC) susceptibility imaging (ASI) of magnetic nanoparticles (mNPs) using low cost instrumentation. The ASI method uses AC magnetic susceptibility measurement to create tomographic images using an array of drive coils, compensation coils and fluxgate magnetometers. Using a spectroscopic approach in conjunction with ASI, a series of tomographic images can be created for each frequency measurement and is termed sASI. The advantage of sASI is that mNPs can be simultaneously characterized and imaged in a biological medium. System calibration was performed by fitting the in-phase and out-of-phase susceptibility measurements of an mNP sample with a hydrodynamic diameter of 100 nm to a Brownian relaxation model (R2 = 0.96). Samples of mNPs with core diameters of 10 and 40 nm and a sample of 100 nm hydrodynamic diameter were prepared in 0.5 ml tubes. Three mNP samples were arranged in a randomized array and then scanned using sASI with six frequencies between 425 and 925 Hz. The sASI scans showed the location and quantity of the mNP samples (R2 = 0.97). Biological compatibility of the sASI method was demonstrated by scanning mNPs that were injected into a pork sausage. The mNP response in the biological medium was found to correlate with a calibration sample (R2 = 0.97, p <0.001). These results demonstrate the concept of ASI and advantages of sASI. PMID:25477704

  7. AC loss calculation of central solenoid model coil

    The AC loss of Central Solenoid Model Coil of ITER is calculated in order to be able to determine the allowable excitation current shape in time with respect to the available cooling capacity at liquid helium temperature. In Part A the theory is summarized essential to present calculation. This covers a semianalytical integral formulation to calculate the magnetic field distribution in the cross-section of a coil and also 2D and 3D differential formulations for eddy current calculation of jackets and structural steel components, respectively. In Part B the conditions and results of calculation are described in detail. Losses are calculated separately in different components. Also the different types of losses are separated, and only one of the followings is considered in the same time; eddy current loss, ferromagnetic hysteresis loss, superconducting hysteresis loss, coupling loss. The followings are concluded. The coupling loss was found to be the largest 83% of the total AC loss supposing 50 msec characteristic time constant. Also significant amount of heat is generated in structural steels, cooling is required for stainless steel structural components. The loss of joints is not large, however concentrated, therefore joints should receive attention. Specially Lap-type joints are critical components. The eddy current and coupling power losses can be significantly decreased by increasing the ramp-up time since they are proportional to the square of flux change rate, while superconducting and ferromagnetic hysteresis power losses decrease linearly with decreasing flux change rate. Joule losses are produced in joints even after the energizing process of the magnet, when it is driven by a constant excitation current. This propose us to keep the time of full power operation short. (J.P.N.)

  8. Effects of oxygenated fuels are questioned at ACS meeting

    The oxygenated fuels business is again under attack. A trio of scientific teams charges that atmospheric monitoring suggests reformulated gasoline is not significantly cutting carbon monoxide (CO) levels and could be raising ambient concentrations of such compounds as formaldehyde and nitrogen oxides. The results, presented at last week's meeting of the American Chemical Society (ACS) in Denver, come less than a month after heightened public concerns about the health effects of methyl tert-butyl ether (MTBE). The scientists reporting at the ACS meeting separately measured air pollution in Denver; Albuquerque, NM; and Brazil-areas that have used oxygenated fuels for several years. The preliminary results, they say, show oxygenates use has little impact on carbon monoxide. And the researchers say they have found relatively high levels of acetaldehyde, formaldehyde, and related compounds, including the mutagen peroxyacetyl nitrate (PAN), in the atmosphere. According to Daniel Grosjean, of environmental research firm DGA (Ventura, Ca), measured levels of acetaldehyde in three Brazilian cities - which began using ethanol fuels in the late 1970s - appear to be among the highest in the world. The findings could cast serious doubts on the ambitious U.S. oxygenates program, which is increasingly requiring cities to use reformulated fuels. In 1988, Denver became the first U.S. city which mandated oxygenated fuels requirements. The region now uses oxygenates-mainly MTBE-for four months each year. But, says Larry G. Anderson, a chemist at the University of Colorado (Denver), we have seen no statistical effect on CO in the air. He points to a predicted 15%-20% drop in ambient CO by 1993. There is considerable evidence formaldehyde increased, Anderson says

  9. Evaluation of AC losses for HT-7U CICC on plasma disruption

    AC loss is one of the main issues in the design of the CICC used for PF and TF coils of superconducting tokamak. A preliminary calculation of AC loss for the designed HT-7U CICCs used for TF magnets is given. The authors only consider the hysteresis and coupling losses related to transversal and longitudinal kinds. In addition to the strand resistive barriers (Pb-30Sn-2Sb coating for NbTi strands), a stainless steel strip has been used inside these cables to reduce the AC loss in this kind of conductor. The available theory has enabled to emphasize the role played by the stainless steel strip in the reduction of total AC losses in this kind of conductor. It was shown that AC losses of cable were affected by the structure and change rate of magnetic field

  10. Dicty_cDB: FC-AC19 [Dicty_cDB

    Full Text Available (... 297 1e-79 AY961548_1( AY961548 |pid:none) Lysiphlebus testaceipes ribosomal ... 297 2e-79 AY120723_1( A...FC-AC19Z (Link to Original site) Representative DNA sequence >FC-AC19 (FC-AC19Q) /CSM/FC/FC-AC/FC-AC19Q.Seq....AU013664 |AU013664.1 Schizosaccharomyces pombe cDNA, clone spc08473. 105 3e-27 3 BW049012 |BW049012.1 Ciona intes...n Score E Sequences producing significant alignments: (bits) Value ( P27685 ) RecName: Full=40S ribosomal protei...nk to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15674-1 Original site URL http:/

  11. Operation and Control of Grid Connected Hybrid AC/DC Microgrid using various RES

    Kodanda Ram R B P U S B

    2014-10-01

    Full Text Available This paper proposes a Hybrid AC/DC Microgrid in alliance with Photo Voltaic (PV energy, Wind Energy and Proton Exchange Membrane (PEM Fuel cells. Microgrids are becoming increasingly attractive to the researchers because of the less greenhouse gases, low running cost, and flexibility to operate in connection with utility grid. The Hybrid AC/DC Microgrid constitutes independent AC and DC subgrids, where all the corresponding sources and loads are connected to their respective buses and these buses are interfaced using an interfacing converter. The Hybrid AC/DC Microgrid increases system efficiency by reducing the multiple reverse conversions involved in conventional RES integration to grid. A Small Hybrid AC/DC Microgrid in grid connected mode was modeled and simulated in MATLAB-SIMULINK environment. The simulation results proves the stable operation considering the uncertainty of generations and loads.

  12. DC Voltage Droop Control Implementation in the AC/DC Power Flow Algorithm: Combinational Approach

    Akhter, F.; Macpherson, D.E.; Harrison, G.P.;

    2015-01-01

    In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include DC voltage droop control. In the VSC based MTDC grids, DC droop control is regarded as more advantageous in terms of...... operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without needing to...... use its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently....

  13. Modelling electroluminescence in insulating polymers under ac stress: effect of voltage offset and pre-stressing

    Ac electroluminescence (EL) in polyethylene films is well documented on experimental grounds but a detailed model encompassing injection and transport is still to be strengthened. In particular, different papers report that the EL under ac sinusoidal voltage for both divergent and uniform field configurations is independent of a superimposed dc voltage offset, which is confirmed by our own measurements. Based on modelling, we show that the dc offset voltage induces a transient behaviour of the ac EL; where the symmetry between the EL peaks occurring during each half cycle of the ac voltage is broken but the same steady state is reached for any value of dc offset. The transient duration is short relative to the timescale of a typical EL measurement explaining why it has not been reported experimentally. It depends on the injection level, charge mobility and recombination efficiency. The model also explains the dependence of ac EL on the presence of homo-space charge near the electrodes. (paper)

  14. Electron elastic scattering off endohedral fullerenes A@C60: The initial insight

    Dolmatov, V K; Hunter, H E

    2014-01-01

    The initial insight into electron elastic scattering off endohedral fullerenes A@C60 is gained in the framework of a theoretical approach where the C60 cage is modelled by a rectangular (in the radial coordinate) potential well, as in many other A@C60 studies. The effect of a noticeably weaker electron elastic scattering off A@C60 compared to that off empty C60 or even the isolated atom A itself, as well as a strong sensitivity of e + A@C60 scattering to the spin of the captured atom A are unraveled, for certain kinds of atoms. Obtained results lay out the initial qualitative basis for identifying interesting measurements and/or more rigorous calculations of e + A@C60 elastic scattering to perform.

  15. Flux avalanches triggered by AC magnetic fields in superconducting thin films

    Flux avalanches are known to occur as a consequence of thermomagnetic instabilities. Some of their fingerprints are jumps in magnetization curves, or a paramagnetic reentrance in AC susceptibility measurements. In this work we have studied flux avalanches triggered by an AC field cycle by means of AC susceptibility and residual magnetization after an applied AC field measured as a function of an AC excitation field (h). These measurements allow comparing both results with magneto-optical imaging carried out in similar conditions. The results show a correspondence for the onset of the avalanche activity, as well as between the residual magnetic moment and the mean gray value calculated from the magneto-optical images in the remanent state.

  16. Difracción acústica por fachadas escalonadas y su aplicación a la arquitectura modernista: una aproximación de su protección acústica

    Simón, Francisco; Rodríguez, Rosa M.ª; Pfretzschner, Jaime

    1999-01-01

    6 pp.-- PACS nr.: 43.20.Gp, 43.50.Gf.-- Comunicación presentada en los siguientes congresos: XXX Jornadas Nacionales de Acústica – TecniAcústica 1999. Encuentro Ibérico de Acústica (Ávila, 20-22 Octubre 1999). Publicado en número especial de la Revista de Acústica: Vol 30(1999).

  17. Data correction on January 10th, 2013 - AcEST | LSDB Archive [Life Science Database Archive metadata

    Full Text Available AcEST Data correction on January 10th, 2013 Errors regarding clone IDs and contig length were found on AcEST... Contig data, and they were corrected on January 10th, 2013. The contents of data correction are listed belo... of This Database Site Policy | Contact Us Data correction on January 10th, 2013 - AcEST | LSDB Archive ...

  18. Characteristics of the magnetic field under hybrid ac/dc high voltage transmission lines

    In recent years, the possibility for ac and dc transmission lines running parallel to each other, sharing the same right-of-way (ROW) or even the same-tower has increased. Design of such hybrid ac/dc networks requires a precise calculation of the magnetic field around and under them. This paper presents quantitative analysis of the magnetic field at 1-m height above ground surface for different hybrid ac/dc transmission lines. Lateral profiles for typical 275, 132 (running in Kuwait), 500, 220 and 132 kV (running in Egypt) ac transmission lines after adding bipolar dc lines are presented. The magnetic vector potential concept, as extended to multi-conductor transmission lines employing the superposition principle is used to model and calculate the RMS values of the magnetic field generated by the hybrid ac/dc lines at any point in the space. The RMS values of the field are determined directly without dividing the ac supply cycle into a sufficient number of subintervals. The presented graphs are useful for setting the maximum allowable ac and dc line current magnitudes, for existing lines, corresponding to a certain safe level of the magnetic field at the edge of right-of-way. (author)

  19. Achieving High Performance in AC-Field Driven Organic Light Sources

    Xu, Junwei; Carroll, David L.; Smith, Gregory M.; Dun, Chaochao; Cui, Yue

    2016-04-01

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m2 with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today’s OLEDs in performance.

  20. The scaling of transport AC losses in Roebel cables with varying strand parameters

    A Roebel cable is a good candidate for low-voltage windings in a high-temperature superconductor (HTS) transformer because of its high current-carrying capability and low AC loss. Transport AC loss measurements were carried out in 1.8 m long 15/5 (fifteen 5 mm wide strands) and 15/4 Roebel cables. The results were compared with those in many Roebel cables composed of 2 mm wide Roebel strands. Comparison of the AC losses hinted that the intrinsic difference in normalized transport AC losses is due to differences in the g/w (ratio of the horizontal gap between the Roebel strands over the Roebel strand width) values. The intrinsic difference was confirmed by measuring transport AC loss in a series of horizontally arranged parallel conductor pairs with various g values. A method to scale transport AC losses in Roebel cables with varying strand parameters was developed. The scaling method will be useful for a rough assessment of AC loss in one-layer solenoid winding coils, such as in a HTS transformer. (papers)

  1. MUC1 and MUC5AC mucin expression in liver fluke-associated intrahepatic cholangiocarcinoma

    Chanchai Boonla; Banchob Sripa; Peti Thuwajit; Ubon Cha-On; Anucha Puapairoj; Masanao Miwa; Sopit Wongkham

    2005-01-01

    AIM: To investigate the expressions of MUC1 and MUC5AC in intrahepatic cholangiocarcinoma (ICC). Association of expressions of mucins MUC1 and MUC5AC with clinical findings, metastasis, and survival of the liver fluke-associated ICC patients was determined.METHODS: The expressions of MUC1 and MUC5AC mucins were examined by immunohistochemical staining in 87cases of histologically-proven ICC. The expressions of mucins in relationship between clinicopathological significance and prognosis of the patients were evaluated.RESULTS: Fifty-two patients (60%) exhibited both MUC1 and MUC5AC expressions, whereas 31% expressed either MUC1or MUC5AC, and 9% expressed neither. High MUC1immunoreactivity displayed a significant correlation with tumor progression as reflected by vascular invasion (P<0.001),whereas high expression of MUC5AC significantly correlated with neural invasion (P = 0.022) and advanced ICC stage (P = 0.008). Patients with high expression of MUC1 had a significantly shorter survival (P = 0.0002). According to multivariate analyses, MUC1 reactivity (P = 0.026),histological grading and stage of tumor represented the least probability of survival.CONCLUSION: MUC1 is overexpressed in liver flukeassociated cholangiocarcinoma and relates to vascular invasion and poor prognosis, whereas MUC5AC mucin is neoexpressed and relates to neural invasion and advanced ICC stage. High MUC1 expression in tumor may be useful for predicting the poor outcome of ICC patients.

  2. Moderately nonlinear diffuse-charge dynamics under an ac voltage.

    Stout, Robert F; Khair, Aditya S

    2015-09-01

    The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of V_{o}/(k_{B}T/e), where V_{o} is the amplitude of the driving voltage and k_{B}T/e is the thermal voltage with k_{B} as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D/λ_{D}L, where D is the ion diffusivity, λ_{D} is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O(V_{o}^{3}) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in V_{o}. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing V_{o}. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer. PMID:26465471

  3. Development of Low AC Loss TFA-MOD Coated Conductors

    Katayama, K.; Machi, T.; Nakamura, T.; Takagi, Y.; Nakaoka, K.; Yoshizumi, M.; Izumi, T.; Shiohara, Y.

    TFA-MOD process is expected to be promising for future applications since it can produce high performance YBCO coated conductors (CCs) with low cost. Applying YBCO CCs to the power electric devices such as transformers and power cables, the reduction of alternating current (AC) loss for long wire is necessary. Multi-filamentation process, which is one of the most effective approaches for AC loss reduction, has been developed by the scribing process. We have developed the filamentation process using chemical etching. MOD derived CCs are, however, easily damaged in the chemical etching process due to existence of pores in a YBCO layer, resulting in critical current (Ic)-degradation and weak delamination strength. Consequently, it is difficult to scribe MOD derived CCs into 1mm-wide filaments for long length using the chemical etching process. Accordingly, we have studied a scribing process using an excimer laser without chemical etching. We defined P' value in this study as a function of irradiated laser power [J] divided by processing speed[m/s]. We studied relationship between the P' value and the results of scribing. It was found that we could scribe the C.C. with a sufficient depth in the condition of large P' value. Furthermore, we found that the Ic was degraded with further increase of the P' value. A 5 mm wide short sample was divided into 10 filaments by the excimer laser scribing process at the P' of 9[J/(m/s)]. The sample revealed reduction of the hysteresis loss down to 1/10 which could be expected from a theoretical prediction using the numbers of the filaments. Ic-degradation was suppressed as 28%, which was smaller than that of the scribed sample using chemical etching (Ic degradation was 38%). Subsequently, we applied the technique to a 100m long YBCO CC. The hysteresis loss of the 100m long MOD derived CC was reduced down to 1/10 (1/the number of filaments) after the multi-filamentation.

  4. AC impedance electrochemical modeling of lithium-ion positive electrodes

    Under Department of Energy's Advanced Technology Development Program,various analytical diagnostic studies are being carried out to examine the lithium-ion battery technology for hybrid electric vehicle applications, and a series of electrochemical studies are being conducted to examine the performance of these batteries. An electrochemical model was developed to associate changes that were observed in the post-test analytical diagnostic studies with the electrochemical performance loss during testing of lithium ion batteries. While both electrodes in the lithium-ion cell have been studied using a similar electrochemical model, the discussion here is limited to modeling of the positive electrode. The positive electrode under study has a composite structure made of a layered nickel oxide (LiNi0.8Co0.15Al0.05O2) active material, a carbon black and graphite additive for distributing current, and a PVDF binder all on an aluminum current collector. The electrolyte is 1.2M LiPF6 dissolved in a mixture of EC and EMC and a Celgard micro-porous membrane is used as the separator. Planar test cells (positive/separator/negative) were constructed with a special fixture and two separator membranes that allowed the placement of a micro-reference electrode between the separator membranes (1). Electrochemical studies including AC impedance spectroscopy were then conducted on the individual electrodes to examine the performance and ageing effects in the cell. The model was developed by following the work of Professor Newman at Berkeley (2). The solid electrolyte interface (SEI) region, based on post-test analytical results, was assumed to be a film on the oxide and an oxide layer at the surface of the oxide. A double layer capacity was added in parallel with the Butler-Volmer kinetic expression. The pertinent reaction, thermodynamic, and transport equations were linearized for a small sinusoidal perturbation (3). The resulting system of differential equations was solved numerically

  5. Fast or Slow, Either Head Can Start the Processive Run of Kinesin-2 KIF3AC.

    Zhang, Pengwei; Rayment, Ivan; Gilbert, Susan P

    2016-02-26

    Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organelle transport in neurons. Our recent studies showed that KIF3AC is as processive as conventional kinesin-1, suggesting that their ATPase mechanochemistry may be similar. However, the presence of two different motor polypeptides in KIF3AC implies that there must be a cellular advantage for the KIF3AC heterodimer. The hypothesis tested was whether there is an intrinsic bias within KIF3AC such that either KIF3A or KIF3C initiates the processive run. To pursue these experiments, a mechanistic approach was used to compare the pre-steady-state kinetics of KIF3AC to the kinetics of homodimeric KIF3AA and KIF3CC. The results indicate that microtubule collision at 11.4 μm(-1) s(-1) coupled with ADP release at 78 s(-1) are fast steps for homodimeric KIF3AA. In contrast, KIF3CC exhibits much slower microtubule association at 2.1 μm(-1) s(-1) and ADP release at 8 s(-1). For KIF3AC, microtubule association at 6.6 μm(-1) s(-1) and ADP release at 51 s(-1) are intermediate between the constants for KIF3AA and KIF3CC. These results indicate that either KIF3A or KIF3C can initiate the processive run. Surprisingly, the kinetics of the initial event of microtubule collision followed by ADP release for KIF3AC is not equivalent to 1:1 mixtures of KIF3AA plus KIF3CC homodimers at the same motor concentration. These results reveal that the intermolecular communication within the KIF3AC heterodimer modulates entry into the processive run regardless of whether the run is initiated by the KIF3A or KIF3C motor domain. PMID:26710851

  6. Power Balance Control in an AC/DC/AC Converter for Regenerative Braking in a Two-Voltage-Level Flywheel-Based Driveline

    Janaína G. Oliveira

    2011-01-01

    Full Text Available The integration of a flywheel as a power handling can increase the energy storage capacity and reduce the number of battery charge/discharge cycles. Furthermore, the ability of recovering energy of the vehicle during breaking can increase the system efficiency. The flywheel-based all-electric driveline investigated here has its novelty in the use of a double-wound flywheel motor/generator, which divides the system in two different voltage levels, enhancing the efficiency of the electric driveline. The connection of two AC electrical machines (i.e., the flywheel and the wheel motor with different and variable operation frequency is challenging. A power matching control applied to an AC/DC/AC converter has been implemented. The AC/DC/AC converter regenerates the electric power converted during braking to the flywheel machine, used here as power handling device. By controlling the power balance, the same hardware can be used for acceleration and braking, providing the reduction of harmonics and robust response. A simulation of the complete system during braking mode has been performed both in Matlab and Simulink, and their results have been compared. The functionality of the proposed control has been shown and discussed, with full regeneration achieved. A round-trip efficiency (wheel to wheel higher than 80% has been obtained.

  7. Segmented superconducting tape having reduced AC losses and method of making

    Foltyn, Stephen R. (Los Alamos, NM); Jia, Quanxi (Los Alamos, NM); Arendt, Paul N. (Los Alamos, NM); Holesinger, Terry G. (Los Alamos, NM); Wang, Haiyan (Los Alamos, NM)

    2009-09-22

    A superconducting tape having reduced AC losses. The tape has a high temperature superconductor layer that is segmented. Disruptive strips, formed in one of the tape substrate, a buffer layer, and the superconducting layer create parallel discontinuities in the superconducting layer that separate the current-carrying elements of the superconducting layer into strips or filament-like structures. Segmentation of the current-carrying elements has the effect of reducing AC current losses. Methods of making such a superconducting tape and reducing AC losses in such tapes are also disclosed.

  8. Estudio del impacto acústico de la llegada del AVE a Alicante

    Pamies Rodríguez, María Isabel

    2014-01-01

    Este estudio del impacto acústico de la alta velocidad en la ciudad de Alicante sirve para ver cómo ha afectado esta nueva línea a la ciudad, sus repercusiones acústicas. Se pretende evaluar el ruido ferreoviario antes y después de la llegada AVE comparando sus decibelios, sus frecuencias y los si los métodos de barrera son útiles y/o necesario. Para ello se van a emplear instrumentos de medida acústica así como el programa Cadna-A para la elaboración de los mapas de ruido junto con AutoCad....

  9. Expeditious synthesis of Mycobacterium tuberculosis sulfolipids SL-1 and Ac2SGL analogues.

    Sarpe, Vikram A; Kulkarni, Suvarn S

    2014-11-01

    M. tuberculosis sulfoglycolipids SL-1 and Ac2SGL are highly immunogenic and potential vaccine candidates. A short and efficient methodology is reported for the synthesis of SL-1 and Ac2SGL analogues via regioselective functionalization of α,α-D-trehalose employing a highly regioselective late stage sulfation, as a key step. The SL-1 analogues 3a and 4 were obtained in 10 and 9 steps in 13.4% and 23.9% overall yields, respectively. The Ac2SGL analogue 5 was synthesized in 5 steps in 18.4% yield. PMID:25322198

  10. A Simple and General Approach to Determination of Self and Mutual Inductances for AC machines

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2011-01-01

    developed so far for inductance determination are often associated with complicated machine magnetic field analysis, which exhibits a difficulty for most students. This paper describes a simple and general approach to the determination of self and mutual inductances of different types of AC machines. A new......Modelling of AC electrical machines plays an important role in electrical engineering education related to electrical machine design and control. One of the fundamental requirements in AC machine modelling is to derive the self and mutual inductances, which could be position dependant. Theories...... determination are given for a 3-phase, salient-pole synchronous machine, and an induction machine....

  11. Estudio y diseño de sistemas para el acondicionamiento acústico

    Jiménez Arranz, Guillermo

    2013-01-01

    La acústica arquitectónica es la rama de la acústica que se dedica al estudio y control del campo sonoro en espacios destinados a la música y la palabra. Esta ciencia tiene la finalidad de recrear las mejores condiciones de escucha en una sala. Las cualidades acústicas que debe tener un espacio varían en función de diversos factores, como el tipo de señal reproducida, la actividad que se va a desarrollar en la sala o incluso los gustos, preferencias y costumbres del público. El acondiciona...

  12. Effect of AC and DC voltage on dielectric properties of CeO2 films

    The capacitance-voltage characteristics have been studied for both AC and DC fields of Al/cerium oxide/Al thin film capacitor structures. Compared to DC fields, these structures can withstand higher AC fields. Capacitance increases with increase in AC and DC fields. The former behaviour is explained on the basis of presence of oxygen vacancies and the latter one is attributed for the Joule heating phenomena. The presence of oxygen vacancies was confirmed from the thermoluminescence studies on these films. (author)

  13. The effect of DC superimposed AC Voltage on Partial Discharges in Dielectric Bounded Cavities

    Olsen, Pål Keim; Mauseth, Frank; Ildstad, Erling

    2014-01-01

    Voltage source converters is used in HVDC stations in offshore HVDC transmission systems, between the AC and DC power grid. The AC ripple voltage on the DC side of the HVDC stations can be in the range of 1-10 % of the nominal DC voltage, depending on the size of the filter employed. For offshore HVDC grids, there is a drive to use polymeric insulated cables on the DC side. This work investigates how an AC voltage at power frequency superimposed on DC voltage influence the partial discharge m...

  14. Low frequency ac conduction and dielectric relaxation in poly(N-methyl pyrrole)

    Amarjeet K Narula; Ramadhar Singh; Subhas Chandra

    2000-06-01

    The ac conductivity and dielectric constant of poly(N-methyl pyrrole) thin films have been investigated in the temperature range 77–350 K and in the frequency range 102–106 Hz. The well defined loss peaks have been observed in the temperature region where measured ac conductivity approaches dc conductivity. These loss peaks are associated with the hopping of the charge carriers. The frequency and temperature dependence of ac conductivity have been qualitatively explained by considering the contribution from two mechanisms; one giving a linear dependence of conductivity on frequency and other having distribution of relaxation times giving rise to broad dielectric loss peak.

  15. Capacitive iris to adjust coupling factor between waveguide and ACS linac in J-PARC

    The beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac has been increased from 181 to 400 MeV by installing Annular-ring Coupled Structure (ACS) cavities in the maintenance period of 2013. Some of the ACS cavities require the correction of the coupling factor between waveguide and the cavity. To adjust the coupling factor, a capacitive iris in the rectangular waveguide was designed. And then, the rectangular waveguide with the capacitive iris was manufactured and installed to one of the ACS cavities. The capacitive iris corrected the coupling factor to the designed value and performed well under high-power operation. (author)

  16. Processamento por ajuste de campo em acústica submarina e aplicações

    C. Soares; Jesus, S.M.

    2004-01-01

    A acústica submarina encontra aplicação em variados problemas tais como detecçãao activa ou passiva e localização de navios e submarinos, comunicações acústicas, tomografia acústica, procura de objectos enterrados e monitorização remota de fenomenos naturais, entre outros. Parte destas aplicações tornaram-se possíveis graças aos avanços tecnológicos da última década, que trouxeram um aumento significativo da capacidade computacional disponível.

  17. Actuación acústica en centro de arte contemporáneo

    VAZQUEZ MARTINEZ, ALBERTO

    2011-01-01

    Trabajo científico técnico. El proyecto trata sobre una intervención acústica en un museo de arte contemporáneo de Valencia, y es un estudio sobre aislamiento y acondicionamiento acústico de las distintas salas del edificio, y que se realizó en colaboración con los autores del proyecto Vazquez Martinez, A. (2011). Actuación acústica en centro de arte contemporáneo. http://hdl.handle.net/10251/11934. Archivo delegado

  18. Reducing AC-Winding Losses in High-Current High-Power Inductors

    Nymand, Morten; Madawala, Udaya K.; Andersen, Michael Andreas E.;

    2009-01-01

    Foil windings are preferable in high-current high-power inductors to realize compact designs and to reduce dc-current losses. At high frequency, however, proximity effect will cause very significant increase in ac resistance in multi-layer windings, and lead to high ac winding losses. This paper...... presents design, analysis and experimental verification of a two winding technique, which significantly reduces ac winding losses without compromising dc losses. The technique uses an inner auxiliary winding, which is connected in parallel with an outer main winding. The auxiliary winding is optimally...

  19. Water calorimetry with thermistor bridge operated in DC and AC mode: comparative results

    Guerra, A.S.; Laitano, R.F.; Petrocchi, A. [Ist. Nazionale di Metrologia delle Radiazioni Ionizzanti, ENEA, Roma (Italy)

    1997-09-01

    An experimental study was carried out to find out the optimal conditions for measuring the output signal in a water calorimeter. To this end the thermistor bridge of the calorimeter was operated in AC and in DC mode, respectively. A comparative analysis of these two alternative methods was the made. In the AC mode measurement a lock-in amplifier based experimental assembly was used and compared to the more conventional system based on a high-sensitivty DC amplifier. The AC system resulted to be preferable as far as the short term and long term reproducibility is concerned. (orig.)

  20. Water calorimetry with thermistor bridge operated in DC and AC mode: comparative results

    An experimental study was carried out to find out the optimal conditions for measuring the output signal in a water calorimeter. To this end the thermistor bridge of the calorimeter was operated in AC and in DC mode, respectively. A comparative analysis of these two alternative methods was the made. In the AC mode measurement a lock-in amplifier based experimental assembly was used and compared to the more conventional system based on a high-sensitivty DC amplifier. The AC system resulted to be preferable as far as the short term and long term reproducibility is concerned. (orig.)

  1. Rotational diffusion model of orientational enhancement in AC field biased photorefractive polymers

    Pedersen, T.G.; Jespersen, K.G.; Johansen, P.M.

    2001-01-01

    The response of photorefractive (PR) polymers subject to AC field biasing is analyzed within the space-charge field formalism. The frequency dependence of orientational enhancement is taken into account using a rotational diffusion model for the angular distribution of chromophores. The possibili...... for simultaneous utilization of AC and orientational enhancement techniques in polymers is discussed for different values of the rotational diffusion time.......The response of photorefractive (PR) polymers subject to AC field biasing is analyzed within the space-charge field formalism. The frequency dependence of orientational enhancement is taken into account using a rotational diffusion model for the angular distribution of chromophores. The possibility...

  2. Flexible AC transmission system devices: allocation and transmission pricing

    The transmission of electricity differs from transportation of any typical commodity by some inherent aspects such as: the production needs to match the consumption at the same time; system control is not an easy task; the electricity flows do not usually follow the economic law. The last aspect is normally observed when transmission systems are included in, for instance, an economic dispatch problem. One way to minimize the operational costs caused by an overloaded transmission system is through the installation of Flexible AC Transmission System (FACTS) devices in the system. They are able to change power flows by modifying the network parameters. This paper focuses on the ability of FACTS devices to change the overall costs of the system and their impact on transmission pricing. The allocation and the determination of the FACTS required are also discussed. Some examples using the IEEE-14 system and the Brazilian electrical system of the Southern region are given to illustrate the concepts introduced in this paper. (author)

  3. Electrohydrodynamics of suspension of liquid drops in AC fields

    Abdul Halim, Md.; Esmaeeli, Asghar

    2012-11-01

    Manipulation of liquid drops by an externally applied electric field is currently the focus of increased attention because of its relevance in a broad range of industrial processes. The effect of a uniform DC electric field on a solitary drop is well studied; however, less is know about the impact of electric field on suspension of liquid drops, and very little information is available on the impact of AC field on a single or a suspension of drops. Here we report the results of Direct Numerical Simulations of electrohydrodynamics of suspension of liquid drops. The governing equations are solved using a front tracking/finite difference technique, in conjunction with Taylor's leaky dielectric model. The imposed electric potential comprises of two parts, a time-independent base and a time-dependent part. The goal is to explore the relative importance of these two components in setting the statistically steady state behavior of the suspension. To this end, we report the results of three sets of simulations, where (i) the time-dependent part act as a perturbation on the base potential, (ii) the two components are of the same order, and (iii) the time-dependent part is much larger than the base potential. The problem is studied as a function of the governing nondimensional parameters.

  4. On two-liquid AC electroosmotic system for thin films.

    Navarkar, Abhishek; Amiroudine, Sakir; Demekhin, Evgeny A

    2016-03-01

    Lab-on-chip devices employ EOF for transportation and mixing of liquids. However, when a steady (DC) electric field is applied to the liquids, there are undesirable effects such as degradation of sample, electrolysis, bubble formation, etc. due to large magnitude of electric potential required to generate the flow. These effects can be averted by using a time-periodic or AC electric field. Transport and mixing of nonconductive liquids remain a problem even with this technique. In the present study, a two-liquid system bounded by two rigid plates, which act as substrates, is considered. The potential distribution is derived by assuming a Boltzmann charge distribution and using the Debye-Hückel linearization. Analytical solution of this time-periodic system shows some effects of viscosity ratio and permittivity ratio on the velocity profile. Interfacial electrostatics is also found to play a significant role in deciding velocity gradients at the interface. High frequency of the applied electric field is observed to generate an approximately static velocity profile away from the Electric Double Layer (EDL). PMID:26773725

  5. AC Electrochemical Deposition of CdS Nanowire Arrays

    QIN; DongHuan

    2001-01-01

    Since the successful growth of carbon nanotubes, one-dimensional materials have been a focused research field both because of their fundamental importance and the wide-ranging potential applications in nano devices. Many approaches are used to fabricate nanowires, such as crystal growth. In order to obtain nanowires whose growth is more easily controlled, electrochemical synthesis in a template is taken as one of the most efficient methods. To date, Co, Fe, Ni, CuCo1-3 and other nanowire arrays have been fabricated successfully by electrodepositing corresponding metal ion into the porous aluminum oxide (PAO) membrane or other non-magnetic materials. Cadmium sulfide(CdS), as one of the most important semiconductor material, is a n-type semiconductor. The ability to fine tune their fundamental electronic and optical properties by simply varying the cruster size, rather than composition, makes them highly attractive for a variety of possible application. In this paper, we report our work of fabricating CdS nanowire arrays based on AC electrolysis into the pores of an anodic aluminum oxide(AAO), the structure and morphology were characterized by XRD and TEM.  ……

  6. AC Electrochemical Deposition of CdS Nanowire Arrays

    QIN DongHuan; LI HuLin

    2001-01-01

    @@ Since the successful growth of carbon nanotubes, one-dimensional materials have been a focused research field both because of their fundamental importance and the wide-ranging potential applications in nano devices. Many approaches are used to fabricate nanowires, such as crystal growth. In order to obtain nanowires whose growth is more easily controlled, electrochemical synthesis in a template is taken as one of the most efficient methods. To date, Co, Fe, Ni, CuCo1-3 and other nanowire arrays have been fabricated successfully by electrodepositing corresponding metal ion into the porous aluminum oxide (PAO) membrane or other non-magnetic materials. Cadmium sulfide(CdS), as one of the most important semiconductor material, is a n-type semiconductor. The ability to fine tune their fundamental electronic and optical properties by simply varying the cruster size, rather than composition, makes them highly attractive for a variety of possible application. In this paper, we report our work of fabricating CdS nanowire arrays based on AC electrolysis into the pores of an anodic aluminum oxide(AAO), the structure and morphology were characterized by XRD and TEM.

  7. Elastic constant of Dendrobium protoplasts in AC electric fields

    Pikul Wanichapichart

    2002-11-01

    Full Text Available This work reports elongation of Dendrobium protoplasts in an ac electric field between two cylindrical electrodes. A protoplast firstly was translated towards an electrode by dielectrophoretic force in 17 kV.m-1 field strength at 1 MHz, and secondly it was elongated due to an interaction between an induced electric dipole (μ and the electric field (E. Protoplast elongation was observed by varying both the field strength at 30, 45, 60, and 85 kV.m-1 and field frequency at 0.5, 1, 5, and 10 MHz. For a given field frequency and field strength, a parameter a/b (major/minor axis was measured as the protoplast elongation.Two-step elongation and restoration phases were observed. The former was completed within 2 minutes of field exposure, and the latter was completed within 15 seconds regardless of the field exposure time between 3 and 20 minutes. The evidence of a complete restoration indicated that the elasticity of the protoplast membrane obeyed Hooke’s law. This study also found that elastic constant k of the membrane varied non-linearly with the field strength. It was found to be from 0.04 to 0.08 mN.m-1, dependent on the field frequency.

  8. General analytical solutions for DC/AC circuit network analysis

    Rubido, Nicolás; Baptista, Murilo S

    2014-01-01

    In this work, we present novel general analytical solutions for the currents that are developed in the edges of network-like circuits when some nodes of the network act as sources/sinks of DC or AC current. We assume that Ohm's law is valid at every edge and that charge at every node is conserved (with the exception of the source/sink nodes). The resistive, capacitive, and/or inductive properties of the lines in the circuit define a complex network structure with given impedances for each edge. Our solution for the currents at each edge is derived in terms of the eigenvalues and eigenvectors of the Laplacian matrix of the network defined from the impedances. This derivation also allows us to compute the equivalent impedance between any two nodes of the circuit and relate it to currents in a closed circuit which has a single voltage generator instead of many input/output source/sink nodes. Contrary to solving Kirchhoff's equations, our derivation allows to easily calculate the redistribution of currents that o...

  9. Influence of compression forces on tablets disintegration by AC Biosusceptometry.

    Corá, Luciana A; Fonseca, Paulo R; Américo, Madileine F; Oliveira, Ricardo B; Baffa, Oswaldo; Miranda, José Ricardo A

    2008-05-01

    Analysis of physical phenomena that occurs during tablet disintegration has been studied by several experimental approaches; however none of them satisfactorily describe this process. The aim of this study was to investigate the influence of compression force on the tablets by associating the AC Biosusceptometry with consolidated methods in order to validate the biomagnetic technique as a tool for quality control in pharmaceutical processes. Tablets obtained at five compression levels were submitted to mechanical properties tests. For uncoated tablets, water uptake and disintegration force measurements were performed in order to compare with magnetic data. For coated tablets, magnetic measurements were carried out to establish a relationship between physical parameters of the disintegration process. According to the results, differences between the compression levels were found for water uptake, force development and magnetic area variation measurements. ACB method was able to estimate the disintegration properties as well as the kinetics of disintegration process for uncoated and coated tablets. This study provided a new approach for in vitro investigation and validated this biomagnetic technique as a tool for quality control for pharmaceutical industry. Moreover, using ACB will also be possible to test these parameters in humans allowing to establish an in vitro/in vivo correlation (IVIVC). PMID:18164605

  10. AC Electric Field Activated Shape Memory Polymer Composite

    Kang, Jin Ho; Siochi, Emilie J.; Penner, Ronald K.; Turner, Travis L.

    2011-01-01

    Shape memory materials have drawn interest for applications like intelligent medical devices, deployable space structures and morphing structures. Compared to other shape memory materials like shape memory alloys (SMAs) or shape memory ceramics (SMCs), shape memory polymers (SMPs) have high elastic deformation that is amenable to tailored of mechanical properties, have lower density, and are easily processed. However, SMPs have low recovery stress and long response times. A new shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive fillers to enhance its thermo-mechanical characteristics. A new composition of shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive functionalized graphene sheets (FGS) to enhance its thermo-mechanical characteristics. The elastic modulus of LaRC-SMPC is approximately 2.7 GPa at room temperature and 4.3 MPa above its glass transition temperature. Conductive FGSs-doped LaRC-SMPC exhibited higher conductivity compared to pristine LaRC SMP. Applying an electric field at between 0.1 Hz and 1 kHz induced faster heating to activate the LaRC-SMPC s shape memory effect relative to applying DC electric field or AC electric field at frequencies exceeding1 kHz.

  11. AC Circuit Measurements with a Differential Hall Element Magnetometer

    Calkins, Matthew W.; Nicks, B. Scott; Quintero, Pedro A.; Meisel, Mark W.

    2013-03-01

    As the biomedical field grows, there is an increasing need to quickly and efficiently characterize more samples at room temperature. An automated magnetometer was commissioned to do these room temperature magnetic characterizations. This magnetometer, which is inspired by a Differential Hall Element Magnetometer,[2] uses two commercially available Hall elements wired in series. One Hall element measures the external magnetic field of a 9 T superconducting magnet and the other measures the same external field plus the field due to the magnetization of the sample that sits on top of the Hall element. The difference between these two Hall elements is taken while a linear stepper motor sweeps through the external magnetic field. The linear motor and data acquisition are controlled by a LabVIEW program. Recently, the system was outfitted for AC circuit measurements and these data will be compared to DC circuit data. In addition, the lowest signal to noise ratio will be found in order to deduce the smallest amount of sample needed to register an accurate coercive field. Supported by the NSF via NHMFL REU (DMR-0654118), a single investigator grant (DMR-1202033 to MWM) and by the UF Undergraduate Scholars Program.

  12. Structural and AC conductivity study of CdTe nanomaterials

    Das, Sayantani; Banerjee, Sourish; Sinha, T. P.

    2016-04-01

    Cadmium telluride (CdTe) nanomaterials have been synthesized by soft chemical route using mercapto ethanol as a capping agent. Crystallization temperature of the sample is investigated using differential scanning calorimeter. X-ray diffraction and transmission electron microscope measurements show that the prepared sample belongs to cubic structure with the average particle size of 20 nm. Impedance spectroscopy is applied to investigate the dielectric relaxation of the sample in a temperature range from 313 to 593 K and in a frequency range from 42 Hz to 1.1 MHz. The complex impedance plane plot has been analyzed by an equivalent circuit consisting of two serially connected R-CPE units, each containing a resistance (R) and a constant phase element (CPE). Dielectric relaxation peaks are observed in the imaginary parts of the spectra. The frequency dependence of real and imaginary parts of dielectric permittivity is analyzed using modified Cole-Cole equation. The temperature dependence relaxation time is found to obey the Arrhenius law having activation energy ~0.704 eV. The frequency dependent conductivity spectra are found to follow the power law. The frequency dependence ac conductivity is analyzed by power law.

  13. Rapid magnetic microfluidic mixer utilizing AC electromagnetic field.

    Wen, Chih-Yung; Yeh, Cheng-Peng; Tsai, Chien-Hsiung; Fu, Lung-Ming

    2009-12-01

    This paper presents a novel simple micromixer based on stable water suspensions of magnetic nanoparticles (i.e. ferrofluids). The micromixer chip is built using standard microfabrication and simple soft lithography, and the design can be incorporated as a subsystem into any chemical microreactor or a miniaturized biological sensor. An electromagnet driven by an AC power source is used to induce transient interactive flows between a ferrofluid and Rhodamine B. The alternative magnetic field causes the ferrofluid to expand significantly and uniformly toward Rhodamine B, associated with a great number of extremely fine fingering structures on the interface in the upstream and downstream regions of the microchannel. These pronounced fingering patterns, which have not been observed by other active mixing methods utilizing only magnetic force, increase the mixing interfacial length dramatically. Along with the dominant diffusion effects occurring around the circumferential regions of the fine finger structures, the mixing efficiency increases significantly. The miscible fingering instabilities are observed and applied in the microfluidics for the first time. This work is carried with a view to developing functionalized ferrofluids that can be used as sensitive pathogen detectors and the present experimental results demonstrate that the proposed micromixer has excellent mixing capabilities. The mixing efficiency can be as high as 95% within 2.0 s and a distance of 3.0 mm from the inlet of the mixing channel, when the applied peak magnetic field is higher than 29.2 Oe and frequency ranges from 45 to 300 Hz. PMID:19921677

  14. Eddy Current Rail Inspection Using AC Bridge Techniques.

    Liu, Ze; Koffman, Andrew D; Waltrip, Bryan C; Wang, Yicheng

    2013-01-01

    AC bridge techniques commonly used for precision impedance measurements have been adapted to develop an eddy current sensor for rail defect detection. By using two detection coils instead of just one as in a conventional sensor, we can balance out the large baseline signals corresponding to a normal rail. We have significantly enhanced the detection sensitivity of the eddy current method by detecting and demodulating the differential signal of the two coils induced by rail defects, using a digital lock-in amplifier algorithm. We have also explored compensating for the lift-off effect of the eddy current sensor due to vibrations by using the summing signal of the detection coils to measure the lift-off distance. The dominant component of the summing signal is a constant resulting from direct coupling from the excitation coil, which can be experimentally determined. The remainder of the summing signal, which decreases as the lift-off distance increases, is induced by the secondary eddy current. This dependence on the lift-off distance is used to calibrate the differential signal, allowing for a more accurate characterization of the defects. Simulated experiments on a sample rail have been performed using a computer controlled X-Y moving table with the X-axis mimicking the train's motion and the Y-axis mimicking the train's vibrational bumping. Experimental results demonstrate the effectiveness of the new detection method. PMID:26401427

  15. AC Glow Discharge Plasma in N2O

    This paper considers the optical and electrical characterization of AC glow discharge plasma in the abnormal glow mode used for optical emission spectroscopy. The total discharge current and applied voltage are measured using conventional techniques. The electrical characteristics of the planer-cathode glow discharge confirmed that the plasma is operating at abnormal discharge mode characterized by the increases in the operating voltage as the current was raised under given pressure. Optical emission spectroscopy was used to determine the main emission lines of the glow discharge plasma of N2O at pressures between 0.5 and 4.0 Torr. It shows that the discharge emission range is mainly within 300-400 nm. The emission lines correspond to NO, O2, and O2+ are the dominant lines in the glow discharge plasma in the present study. Intensity of the emission lines show linear increase with the discharge current up to 0.4 A followed by saturation at higher currents. No emission lines were observed in this work corresponding to atomic oxygen or nitrogen

  16. ac susceptibility study of a magnetite magnetic fluid

    Ayala-Valenzuela, O. E.; Matutes-Aquino, J. A.; Galindo, J. T. Elizalde; Botez, C. E.

    2009-04-01

    Magnetite nanometric powder was synthesized from metal salts using a coprecipitation technique. The powders were used to produce magnetic fluid via a peptization method, with hydrocarbon Isopar M as liquid carrier and oleic acid as surfactant. The complex magnetic susceptibility χ =χ'+iχ″ was measured as a function of temperature T in steps of 2.5 K from 3 to 298 K for frequencies ranging from f =10 to 10 000 Hz. The magnetic fluid real and imaginary components of the ac susceptibility show a prominent maximum at temperatures that increase with the measuring frequency, which is attributed to a spin-glass-like behavior. The peak temperature Tp1 of χ″ depends on f following the Vogel-Fulcher law f =f0 exp[E /kB(Tp1-T0)], where f0 and E are positive constants and T0 is a parameter related to particle interactions. There is another kind of peak temperature, Tp2, in the loss factor tan δ =χ″/χ' which is related to a magnetic aftereffect. The peak temperature Tp2 is far less than Tp1 and shows an Arrhenius-type dependence on f.

  17. Fuzzy Controlled Parallel AC-DC Converter for PFC

    M Subba Rao

    2011-01-01

    Full Text Available Paralleling of converter modules is a well-known technique that is often used in medium-power applications to achieve the desired output power by using smaller size of high frequency transformers and inductors. In this paper, a parallel-connected single-phase PFC topology using flyback and forward converters is proposed to improve the output voltage regulation with simultaneous input power factor correction (PFC and control. The goal of the control is to stabilize the output voltage of the converter against the load variations. The paper presents the derivation of fuzzy control rules for the dc/dc converter circuit and control algorithm for regulating the dc/dc converter. This paper presents a design example and circuit analysis for 200 W power supply. The proposed approach offers cost effective, compact and efficient AC/DC converter by the use of parallel power processing. MATLAB/SIMULINK is used for implementation and simulation results show the performance improvement.

  18. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals

    Tresguerres, M.; Barott, KL; Barron, ME; Roa, JN

    2014-01-01

    Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3 -, and sAC has been confirmed to be a HCO3 - sensor in a variety of mammalian cell types. In addition, sA...

  19. Procedimiento para diseñar una cámara acústica reverberante para ensayos auditivos con animales

    Cobo, Pedro; Varela-Nieto, Isabel; Murillo-Cuesta, Silvia; Cediel, Rafael

    2008-01-01

    Procedimiento para diseñar una cámara acústica reverberante para ensayos auditivos con animales. El objeto principal de la presente invención es procedimiento para diseñar una cámara acústica reverberante de dimensiones (L1, L2, L3) cuyo campo acústico sea homogéneo espacial y espectralmente; las operaciones del procedimiento son: elegir una de las dimensiones L3; obtener las funciones (valor medio del campo acústico) y (desviación cuadrática media del campo acústico);...

  20. Comparison of Central Corneal Thickness Measured by AC-OCT and OCT%AC-OCT与OCT测量中央角膜厚度的比较

    曾阳发; 刘杏; 蔡小于; 黄晶晶; 郑小萍; 李媚; 王涛; 毛真

    2007-01-01

    [目的]探讨眼前段光学相干断层扫描仪(AC-OCT)测量中央角膜厚度(CCT),并与光学相干断层扫描仪(OCT)进行比较.[方法]分别用OCT和AC-OCT的高分辨单线扫描程序(High Resolution Corneal)、角膜地形图程序(Pachymerry Map)测量30例(30只眼)正常受试者的CCT.采用配对t检验对之进行比较;用相关分析方法分析两种仪器测量值之间的相关性;随机选择1只眼分别用两种OCT仪依次重复测量CCT 10次,采用变异系数作为评判标准,比较测量的可重复性.[结果]OCT测量的CCT平均值为526.0(s=29.4)μm;AC-OCT角膜地形图程序测量的中央2 mm区域最小值、最大值和平均值的均值分别是512.6(s=31.7)μm,522.0(s=32..3)μm和515.0(s=31.7)μm,高分辨单线扫描程序测得的CCT值为518.9(s=31.1)μm;OCT测量的CCT值比AC-OCT的各测量值分别大13.3(s=5.9)μm(P=0.000);3.9(s=6.3)μm(P=0.002);11.0(s=5.9)μm(P=0.000);7.0(s=6.4)μm(P=0.000).OCTCCT与AC-OCT各CCT值有很好的相关性(rOCT-AC-OCT Min=0.987,rOCT-AC-OCT Max=0.987,rOCT-AC-OCT Mean=0.988,rOCT-AC-OCT Flap=0.986,P均=0.000).OCT测量CCT值10次的变异系数为0.67%.AC-OCT角膜地形图中央2 mm区域中的最小值、最大值和平均值以及高分辨单线扫描程序测量值的变异系数分别为0.23%,0.48%,0.20%和0.37%.[结论]OCT测量的CCT值比AC-OCT的各CCT值大,两种OCT的测量值相关性较好;AC-OCT测量CCT的可重复性稍好于OCT.

  1. Fine tuning of cascaded d-q axis controller for AC-DC-AC converter without DC link capacitor using artificial neural network

    Padmanaban Sanjeevikumar; Balakrishnan GeethaLakshmi; Perumal Danajayan

    2008-01-01

    This paper presents an artificial neural network (ANN) based approach to tune the parameters of the cascaded d-q axis controller for an AC-DC-AC converter without dc link capacitor. The proposed converter uses the cascaded d-q axis controller on the rectifier side and space vector pulse width modulation on the inverter side. The feed-forward ANN with the error back-propagation training is employed to tune the parameters of the cascaded d-q axis controller. The converter topology provides simp...

  2. Influence of the iodide/iodine redox system on the self-discharge of AC/AC electrochemical capacitors in salt aqueous electrolyte

    Qamar Abbas

    2015-12-01

    Full Text Available Self-discharge (SD of AC/AC (AC=activated carbon electrochemical capacitors in aqueous solutions of lithium sulfate (Li2SO4 and lithium sulfate+iodide salts (Li2SO4+KI or Li2SO4+LiI was investigated at 24 °C and −40 °C after cell potential hold at values from 1 V to 1.6 V. At 24 °C, the cells exhibit lower SD in Li2SO4+KI than in Li2SO4, owing to the redox activity of the 2I−/I2 system which drives the positive AC electrode to operate in narrow potential range and display lower potential drop than in Li2SO4. At −40°C, the capacitors exhibit comparable and reduced SD both in Li2SO4+LiI and Li2SO4, whatever the holding cell potential. Three-electrode cell experiments demonstrate that, at −40 °C, hydrogen chemisorption is thermodynamically unfavored under negative polarization, while the activity of the 2I−/I2 redox system under positive polarization is only slightly reduced. As a consequence, the AC/AC cells in Li2SO4 exhibit a typical electrical double-layer performance at −40°C, whereas they still behave as hybrid ones in Li2SO4+LiI, with twice higher capacitance than in Li2SO4. The (Ui-Ut vs t1/2 plots demonstrate that SD is essentially controlled by diffusion at −40°C, suggesting that it originates from bulkier hydrated ions. Overall, in the investigated temperature range, the AC/AC capacitors in Li2SO4+LiI demonstrate low self-discharge and high capacitance, while being able to operate up to 1.6 V.

  3. Non-oxidized porous silicon-based power AC switch peripheries

    Menard, Samuel; Fèvre, Angélique; Valente, Damien; Billoué, Jérôme; Gautier, Gaël

    2012-10-01

    We present in this paper a novel application of porous silicon (PS) for low-power alternating current (AC) switches such as triode alternating current devices (TRIACs) frequently used to control small appliances (fridge, vacuum cleaner, washing machine, coffee makers, etc.). More precisely, it seems possible to benefit from the PS electrical insulation properties to ensure the OFF state of the device. Based on the technological aspects of the most commonly used AC switch peripheries physically responsible of the TRIAC blocking performances (leakage current and breakdown voltage), we suggest to isolate upper and lower junctions through the addition of a PS layer anodically etched from existing AC switch diffusion profiles. Then, we comment the voltage capability of practical samples emanating from the proposed architecture. Thanks to the characterization results of simple Al-PS-Si(P) structures, the experimental observations are interpreted, thus opening new outlooks in the field of AC switch peripheries.

  4. Top 10 Remand Reasons Cited by the AC on Remands of RRs or Own Motion Reviews

    Social Security Administration — Longitudinal report detailing the top 10 reasons for remands cited by the Appeals Council (AC) when returning requests for review (RRs) or own motion review actions...

  5. IEEE 802.11ac: Next Generation High Speed Wireless LAN Technology

    Ms. Laxmi Chaudhary

    2015-06-01

    Full Text Available This paper gives an overview of the IEEE 802.11ac which has been proposed to enhance the throughput of IEEE 802.11n beyond Gigabit-per second rates. 802.11ac adds multi-user access techniques in the form of downlink multi-user (DL MU multiple input multiple output (MIMOand 80 and 160 MHz channels in the 5 GHz band for applications such as multiple simultaneous video streams throughout the home. For this the IEEE 802.11ac task group is working on the amendment that has goal of reaching maximum network throughput of atleast 1 Gbps on bands below 6GHz & continuing to support the legacy of 5GHz 802.11 devices. In this paper we describe the 802.11ac key features, channelization, MAC modifications and modulation enhancements and its various applications in wireless technology.

  6. Help Desk Answers: Surgery vs conservative management for AC joint repair: How do the 2 compare?

    Matchin, Bruce; Yee, Bruce; Mott, Timothy

    2016-04-01

    When not considering the grade of acromioclavicular (AC) joint dislocation, both conservative and surgical management lead to positive outcomes, although surgically managed patients require more time out of work. PMID:27262254

  7. Power flow analysis for droop controlled LV hybrid AC-DC microgrids with virtual impedance

    Li, Chendan; Chaudhary, Sanjay; Vasquez, Juan Carlos;

    2014-01-01

    The AC-DC hybrid microgrid is an effective form of utilizing different energy resources and the analysis of this system requires a proper power flow algorithm. This paper proposes a suitable power flow algorithm for LV hybrid AC-DC microgrid based on droop control and virtual impedance. Droop and...... algorithm makes it a potential method for planning, dispatching and operation of droop controlled LV hybrid AC-DC....... virtual impedance concepts for AC network, DC network and interlinking converter are reviewed so as to model it in the power flow analysis. The validation of the algorithm is verified by comparing it with steady state results from detailed time domain simulation. The effectiveness of the proposed...

  8. Bridging in contaminated transformer oil under DC and AC electric field

    There are two experimental set up have been established to investigate the bridging effect between two electrodes with different potentials under ac and dc voltages. This paper will explain the full details of the experimental setup and the results. These experiments carried out on pressboard particles under three different levels of ac and dc voltages. Several contamination levels have been investigated. Optical images of particle accumulation have been recorded along with associated conduction current measurement during experiments. At higher voltages the rate of bridge formation is increased along with an associated current increase. The major differences between ac and dc bridges are the shapes of the particle accumulation. The bridge formation rate for ac is slower than dc

  9. System and Battery Charge Control for PV-Powered AC Lighting Systems

    Kern, G.

    1999-04-01

    This report reviews a number of issues specific to stand-alone AC lighting systems. A review of AC lighting technology is presented, which discusses the advantages and disadvantages of various lamps. The best lamps for small lighting systems are compact fluorescent. The best lamps for intermediate-size systems are high- or low-pressure sodium. Specifications for battery charging and load control are provided with the goal of achieving lamp lifetimes on the order of 16,000 to 24,000 hours and battery lifetimes of 4 to 5 years. A rough estimate of the potential domestic and global markets for stand-alone AC lighting systems is presented. DC current injection tests were performed on high-pressure sodium lamps and the test results are presented. Finally, a prototype system was designed and a prototype system controller (with battery charger and DC/AC inverter) was developed and built.

  10. Retention studies of recoiling daughter nuclides of 225Ac in polymer vesicles

    Alpha radionuclide therapy is steadily gaining importance and a large number of pre-clinical and clinical studies have been carried out. However, due to the recoil effects the daughter recoil atoms, most of which are alpha emitters as well, receive energies that are much higher than the energies of chemical bonds resulting in decoupling of the radionuclide from common targeting agents. Here, we demonstrate that polymer vesicles (i.e. polymersomes) can retain recoiling daughter nuclei based on an experimental study examining the retention of 221Fr and 213Bi when encapsulating 225Ac. - Highlights: • First reported loading of 213Bi and 225Ac in polymer vesicles (i.e. polymersomes). • Encapsulating 225Ac in polymersomes results in up to 69 % recoil retention of 221Fr. • Encapsulating 225Ac in polymersomes results in up to 53 % recoil retention of 213Bi

  11. Measurement of the efficiency of cell membrane electroporation using pulsed ac fields

    Electroporation is a long-established technique used to deliver molecules to cells. Most in vivo electroporation protocols entail applying square-wave, or monotonically-decreasing pulses but relatively few have explored the use of pulsed ac fields. This study measures the efficiency of electroporation in human kidney embryonal cells, using pulsed ac electric fields of peak amplitude 30-200 kV m-1. The results indicate that optimum electroporation efficiencies of up to 70% can be achieved using pulses at frequencies of 20-160 kHz. Increasing the field strength results in higher electroporation efficiency, but also increases cell kill. This study confirms that efficient electroporation may be achieved using pulsed ac fields. This finding raises the possibility of a wider range of clinical and laboratory applications based on ac technology and avoiding the use of invasive needle electrodes

  12. Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results

    Chandler, K.; Eudy, L.

    2007-03-01

    This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

  13. Spin exchange collision mixing of the K and Rb ac Stark shifts

    Chen, Yao; Fang, Jiancheng

    2016-01-01

    In a hybrid pumping alkali vapor cell that both K and Rb are filled, K atom spins are optically pumped by laser and Rb atom spins are polarized by the K spins through spin exchange. We find that the AC Stark shift of the Rb atoms is composed of not only the AC Stark shift of the Rb atoms caused by the far off resonant pumping laser which is tuned to the K absorption lines, but also the AC Stark shift of the K atom spins. The mixing of the light shifts through fast spin exchange between K and Rb atoms are studied in this paper and we demonstrate a K-Rb-21Ne co-magnetometer in which the AC Stark shift of the Rb atoms are reduced by the collision mixing.

  14. Download - AcEST | LSDB Archive [Life Science Database Archive metadata

    Full Text Available [ Credits ] BLAST Search Image Search Home About Archive Update History Contact us ...t This Database Database Description Download License Update History of This Database Site Policy | Contact Us Download - AcEST | LSDB Archive ...

  15. Complete Genome Sequences of Seven Helicoverpa armigera SNPV-AC53-Derived Strains

    2016-01-01

    Wild-type baculovirus isolates typically consist of multiple strains. We report the full genome sequences of seven alphabaculovirus strains derived by passage through tissue culture from Helicoverpa armigera SNPV-AC53 (KJ909666). PMID:27151787

  16. NCDC International Best Track Archive for Climate Stewardship (IBTrACS) Project, Version 3

    National Oceanic and Atmospheric Administration, Department of Commerce — The International Best Track Archive for Climate Stewardship (IBTrACS) dataset was developed by the NOAA National Climatic Data Center, which took the initial step...

  17. Structural and AC loss study for pure and doped MgB{sub 2} superconductor

    Hansdah, J. S.; Sarun, P. M., E-mail: sarun.res@gmail.com [Functional Ceramics Lab, Department of Applied Physics, Indian School of Mines (ISM), Dhanbad – 826004 (India)

    2015-06-24

    Superconducting polycrystalline bulk MgB{sub 2} samples doped with n-C, n-Y{sub 2}O{sub 3} and n-Ho{sub 2}O{sub 3} were prepared by powder-in-sealed (PIST) method. XRD measurement shows the influence of dopants on phase and lattice parameters of samples. The ac susceptibility measurement reveals ac loss and activation energy of the samples. Nano-C doped sample shows less ac loss in all frequency (208 Hz – 999 Hz) among the doped samples; whereas n-Ho{sub 2}O{sub 3} doped sample shows highest ac loss. The activation energy is high for rare earth (n-Y{sub 2}O{sub 3} and n-Ho{sub 2}O{sub 3}) doped samples as compare to n-C doped samples which reveals the enhancement in flux-pinning properties of these materials.

  18. Structural, dielectric and AC conductivity properties of Co2+ doped mixed alkali zinc borate glasses

    Madhu, B. J.; Banu, Syed Asma; Harshitha, G. A.; Shilpa, T. M.; Shruthi, B.

    2013-02-01

    The Co2+ doped 19.9ZnO+5Li2CO3+25Na2CO3+50B2O3 (ZLNB) mixed alkali zinc borate glasses have been prepared by a conventional melt quenching method. The structural (XRD & FT-IR), dielectric and a.c. conductivity (σac) properties have been investigated. Amorphous nature of these glasses has been confirmed from their XRD pattern. The dielectric properties and electrical conductivity (σac) of these glasses have been studied from 100Hz to 5MHz at the room temperature. Based on the observed trends in the a.c. conductivities, the present glass samples are found to exhibit a non-Debye behavior.

  19. Transport ac losses in Bi-2223 multifilamentary tapes - conductor materials aspect

    Transport ac losses in technical superconductors based on Bi-2223 tape material are influenced by many parameters. The major factors that define the ac performance of such conductors are the following: the size and number of filaments, their geometrical arrangement in the cross-section of the conductor, the twist pitch length, the resistivity of the matrix, the presence of oxide barriers around the filaments and deformation procedures such as sequential pressing or rolling followed by appropriate thermal treatment. In the present paper the above aspects are addressed from the viewpoint of the materials science of technical conductor design. Transport ac losses at power frequencies in different types of Bi-2223 conductor are presented and analysed. The results of conductor design analysis with respect to the coexistence of the superconductor with other materials in the conductor structure are presented. New concepts for minimization of the transport ac losses are discussed in detail. (author)

  20. Electric field in an AC dielectric barrier discharge overlapped with a nanosecond pulse discharge

    Goldberg, Benjamin M.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-08-01

    The effect of ns discharge pulses on the AC barrier discharge in hydrogen in plane-to-plane geometry is studied using time-resolved measurements of the electric field in the plasma. The AC discharge was operated at a pressure of 300 Torr at frequencies of 500 and 1750 Hz, with ns pulses generated when the AC voltage was near zero. The electric field vector is measured by ps four-wave mixing technique, which generates coherent IR signal proportional to the square of electric field. Absolute calibration was done using an electrostatic (sub-breakdown) field applied to the discharge electrodes, when no plasma was generated. The results are compared with one-dimensional kinetic modeling of the AC discharge and the nanosecond pulse discharge, predicting behavior of both individual micro-discharges and their cumulative effect on the electric field distribution in the electrode gap, using stochastic averaging based on the experimental micro-discharge temporal probability distribution during the AC period. Time evolution of the electric field in the AC discharge without ns pulses, controlled by a superposition of random micro-discharges, exhibits a nearly ‘flat top’ distribution with the maximum near breakdown threshold, reproduced quite well by kinetic modeling. Adding ns pulse discharges on top of the AC voltage waveform changes the AC discharge behavior in a dramatic way, inducing transition from random micro-discharges to a more regular, near-1D discharge. In this case, reproducible volumetric AC breakdown is produced at a well-defined moment after each ns pulse discharge. During the reproducible AC breakdown, the electric field in the plasma exhibits a sudden drop, which coincides in time with a well-defined current pulse. This trend is also predicted by the kinetic model. Analysis of kinetic modeling predictions shows that this effect is caused by large-volume ionization and neutralization of surface charges on the dielectrics by ns discharge pulses. The present