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1

Correction for Thermal EMFs in Thermocouple Feedthroughs  

NASA Technical Reports Server (NTRS)

A straightforward measurement technique provides for correction of thermal-electromotive-force (thermal-EMF) errors introduced by temperature gradients along the pins of non-thermocouple-alloy hermetic feedthrough connectors for thermocouple extension wires that must pass through bulkheads. This technique is an alternative to the traditional technique in which the thermal-EMF errors are eliminated by use of custom-made multipin hermetic feedthrough connectors that contain pins made of the same alloys as those of the thermocouple extension wires. One disadvantage of the traditional technique is that it is expensive and time-consuming to fabricate multipin custom thermocouple connectors. In addition, the thermocouple-alloy pins in these connectors tend to corrode easily and/or tend to be less rugged compared to the non-thermocouple-alloy pins of ordinary connectors. As the number of thermocouples (and thus pins) is increased in a given setup, the magnitude of these disadvantages increases accordingly. The present technique is implemented by means of a little additional hardware and software, the cost of which is more than offset by the savings incurred through the use of ordinary instead of thermocouple connectors. The figure schematically depicts a typical measurement setup to which the technique is applied. The additional hardware includes an isothermal block (made of copper) instrumented with a reference thermocouple and a compensation thermocouple. The reference thermocouple is connected to an external data-acquisition system (DAS) through a two-pin thermocouple-alloy hermetic feedthrough connector, but this is the only such connector in the apparatus. The compensation thermocouple is connected to the DAS through two pins of the same ordinary multipin connector that connects the measurement thermocouples to the DAS.

Ziemke, Robert A.

2006-01-01

2

The theory of the thermal EMF of semi-conductors  

Microsoft Academic Search

After a discussion of the present theory of the thermal EMF of semi-conductors, the theory is extended to non-homogeneous semi-conductors. Its relationship to thermodynamics is discussed and it is then applied to the study of the influence of potential barriers. Further cases are discussed in which the velocity or the concentration of electrons does not conform to a state of

Jan Tauc

1953-01-01

3

A very low thermal EMF computer-controlled scanner  

NASA Astrophysics Data System (ADS)

A very low thermal electromotive force (EMF) scanner was designed in our laboratory five years ago. The device was developed to automatically calibrate up to 12 Zener-based voltage standards by comparison to a programmable Josephson voltage standard, but can be used in any set-up that requires automation to set electrical contacts with a repeatability of the thermal EMFs at the nanovolt level. This paper explains how this device achieves robustness of metrological characteristics even after several thousand connections since its first installation. One scanner position shows a voltage offset of 60 nV with a standard deviation of 7 nV while the remaining 11 show offset values between -15 nV and +25 nV with an associated Type A uncertainty varying from 2 to 7 nV. Herein, we present the results of a series of measurements on all channels. Sub-nanovolt residual thermal short EMF variations are demonstrated using Allan variance statistical analysis.

Chayramy, R.; Solve, S.

2013-02-01

4

Determining the absolute thermo emfs of conductors using a Y 1 Ba 2 Cu 3 O 7 ? ? rod  

Microsoft Academic Search

The voltage drop on a 110-mm-long Y1Ba2Cu3O7 ? ? (YBCO) rod with a diameter of 7 mm bearing a current of 1 A has been studied as a function of the temperature. It is shown\\u000a that YBCO rods can be used to measure the absolute thermo emf of conductors in a range of temperatures up to the onset of\\u000a breakage

S. A. Churin

2009-01-01

5

Determining the absolute thermo emfs of conductors using a Y1Ba2Cu3O7 - delta rod  

Microsoft Academic Search

The voltage drop on a 110-mm-long Y1Ba2Cu3O7 - delta (YBCO) rod with a diameter of 7 mm bearing a current of 1 A has been studied as a function of the temperature. It is shown that YBCO rods can be used to measure the absolute thermo emf of conductors in a range of temperatures up to the onset of breakage

S. A. Churin

2009-01-01

6

Thermal emf of Y-Ba-Cu-O ceramics with different oxygen contents under hydrostatic pressure up to 12 kbar  

Microsoft Academic Search

The temperature dependence of the thermal emf and electrical conductivity of YBa2Cu3O(x) ceramics (x = 6.4, 6.6, and 6.0) under hydrostatic pressure up to 12 kbar was investigated experimentally in the temperature range 50-300 K. The thermal emf is found to be positive for all T, x, and P; the temperature dependence of the thermal emf features a maximum in

V. F. Kraidenov; E. S. Itskevich; N. M. Kotov

1990-01-01

7

Testing and evaluation of thermal cameras for absolute temperature measurement  

Microsoft Academic Search

The accuracy of temperature measurement is the most important criterion for the evaluation of thermal cameras used in applications requiring absolute temperature measurement. All the main international metrological organizations currently propose a parameter called uncertainty as a measure of measurement accuracy. We propose a set of parameters for the characterization of thermal measurement cameras. It is shown that if these

Krzysztof Chrzanowski; Joachim Fischer; Robert Matyszkiel

2000-01-01

8

Thermal emf in alloys of nickel with hafnium, tungsten, and rhenium in range 77 to 1300°K  

Microsoft Academic Search

Thermo-emf's were measured in Ni--Hf, Ni--W and Ni--Re alloys at 273 to ; 1273 deg K with respect to platinum, and at 77 to 273 deg K with respect to ; copper. The thermo-emf value in Ni--W and Ni--Re alloys is primarily positive ; with the exception of the Ni + 1.08 at.% Re where at temperatures above 400 deg

Z. I. Ali-zade; V. M. Beilin; T. I. Zeinalov; I. L. Rozelberg

1973-01-01

9

Thermal-electrical modeling of absolute cryogenic radiometers  

NASA Astrophysics Data System (ADS)

This study employs finite-element (FE) software to model the nonlinear thermal-electrical dynamic response of absolute cryogenic radiometers (ACRs). The high-accuracy cryogenic radiometer (HACR) and laser-optimized cryogenic radiometer (LOCR) have been analyzed to determine the input geometric and thermal parameters. Comparisons between the FE model and experimental results for the HACR and LOCR show an agreement in temperature within 2%. A proportional-integral-derivative (PID) temperature-control algorithm has been developed for both the receiver and the heat sink. The optimized control parameters are related to the thermal conductances and time constants of the radiometers. The LOCR receiver has the advantage of a reduction in measurement time over the HACR receiver; whereas the HACR heat sink offers the advantage of better temperature stability over the LOCR heat sink. The time constant of the HACR receiver can be significantly reduced without degrading the performance. The temperature stability of the LOCR heat sink can be improved by a factor of two by using a larger heat-sink heat capacity, CHS?80 mJ/K. This research will help improve future design of ACRs.

Pearson, D. A.; Zhang, Z. M.

1999-07-01

10

Analysis of induced EMF waveforms and torque ripple in a brushless permanent magnet machine  

Microsoft Academic Search

Permanent magnet machines with trapezoidal back EMF waveform have been the subject of several papers in the past. The simplicity in control and the absence of an absolute position sensor makes this type of motor very attractive. Idealized analysis of such a machine is simple and will result in trapezoidal or square wave back EMF waveforms depending on the assumptions

Tomy Sebastian; Vineeta Gangla

1996-01-01

11

Analysis of induced EMF and torque waveforms in a brushless permanent magnet machine  

Microsoft Academic Search

Permanent magnet machines with trapezoidal back EMF waveform have been the subject of several papers in the past. The simplicity in control and the absence of an absolute position sensor makes this type of motor very attractive. Idealized analysis of such a machine is simple and will result in trapezoidal or square wave back EMF waveforms depending on the assumptions

Tomy Sebastian; Vineeta Gangla

1994-01-01

12

EMF Genes Regulate Arabidopsis Inflorescence Development  

Microsoft Academic Search

Mutations in EMBRYONlC FLOWER (EMF) genes EMFl and EMf2 abolish rosette development, and the mutants pro- duce either a much reduced inflorescence or a transformed flower. These mutant characteristics suggest a repressive effect of EMF activities on reproductive development. To investigate the role of EMf genes in regulating reproductive development, we studied the relationship between EMf genes and the genes

Lingjing Chen; Jin-Chen Cheng; Linda Castle; Renee Sung

1997-01-01

13

Theoretical Comparison of Motional and Transformer EMF Device Damping Efficiency  

Microsoft Academic Search

In this paper, theoretical comparison between electromagnetic dampers based on a ``motional emf'' and ``transformer emf'' design is presented. Transformer emf devices are based on the generation of emf in a stationary circuit, in which the emf is generated by a time-varying magnetic field linking the circuit. Motional emf devices are based on the generation of emf due to a

K. E. Graves; D. Toncich; P. G. Iovenitti

2000-01-01

14

THEORETICAL COMPARISON OF MOTIONAL AND TRANSFORMER EMF DEVICE DAMPING EFFICIENCY  

Microsoft Academic Search

In this paper, theoretical comparison between electromagnetic dampers based on a “motional emf” and “transformer emf” design is presented. Transformer emf devices are based on the generation of emf in a stationary circuit, in which the emf is generated by a time-varying magnetic field linking the circuit. Motional emf devices are based on the generation of emf due to a

K. E. GRAVES; D. TONCICH; P. G. IOVENITTI

2000-01-01

15

New bimetallic EMF cell shows promise in direct energy conversion  

NASA Technical Reports Server (NTRS)

Concentration cell, based upon a thermally regenerative cell principle, produces electrical energy from any large heat source. This experimental bimetallic EMF cell uses a sodium-bismuth alloy cathode and a pure liquid sodium anode. The cell exhibits reliability, corrosion resistance, and high current density performance.

Hesson, J. C.; Shimotake, H.

1968-01-01

16

Is There an EMF-Cancer Connection?  

Microsoft Academic Search

Scientists would also like to understand the biological processes by which EMF exposure might lead to cancer. Laboratory investigations have shown that EMFs can indeed elicit some effects in cells, including changes in hormone levels, in protein synthesis, and in ion flow across cell membranes. But so far this research has not produced clear laboratory evidence that EMFs either cause

Robert Pool

1990-01-01

17

Sourcebook for utility communications on EMF  

SciTech Connect

All electric utilities now face, or soon will be facing, many issues over the public concern of Electric and Magnetic fields (EMF). Our purpose in writing this manual is to provide utilities with the best current information about two questions: What is the present state of scientific knowledge about EMF How can we communicate effectively with the public about EMF

Creighton, J.L.; Banks, R.S.; Duening, T. (Creighton and Creighton, Inc., Palo Alto, CA (United States))

1992-06-01

18

EMF effects on microcirculatory system  

Microsoft Academic Search

Authors review the importance of studying the effects of electromagnetic fields (EMF) on microcirculatory system, especially\\u000a in respect of possibility that vasculature may have direct and indirect role in interaction of static magnetic fields (SMF).\\u000a We outline the physiological importance of microcirculation and relatively new methods of evaluation technique in vivo and\\u000a explain in details the local and\\/or whole body exposure

Chiyoji Ohkubo; Hideyuki Okano; Akira Ushiyama; Hiroshi Masuda

2007-01-01

19

EMF and the public health  

SciTech Connect

The availability of reasonably priced electric power underpins the American standard of living, the nation`s industrial strength, and even our creature comforts. Utility experts estimate that by the end of this century electric utility infrastructure such as transmission lines, distribution lines, substations, and the like will expand by as much as 15 percent to serve increased customer demands for power. The electric utility industry today, however, is faced with an unanticipated consequence of its own success as health questions have been raised regarding electric and magnetic fields (EMF or EMR). These fields are created whenever electric current passes through power lines or electrical equipment. While people are exposed to EMF from electrical appliances, household wiring, and even household water pipes to which the home electrical system has been grounded, most of the attention has centered on high-voltage transmission lines and, to a lesser extent, neighborhood distribution lines. The scientific debate has been fueled by epidemiological studies. Epidemiology, which is the study of the distribution of diseases in the human population, is useful in identifying statistical associations that may reflect a causal relationship between an exposure and a disease. Some EMF epidemiological studies have reported positive statistical associations between residential and occupational exposures to EMF and certain childhood and adult cancers, including leukemia, brain cancer, lymphoma, and breast cancer. While scientists debate the meaning of these studies and conduct further studies, the debate is now moving into America`s courtrooms as private litigants seek compensation for physical harm and damage to property values.

Krieger, R.W. [Krieger & Associates, Washington, DC (United States); Withey, M.E. [Shroeter, Goldmark & Bender, Seattle, WA (United States)

1994-12-31

20

EMF recommendations specific for children?  

PubMed

When discussing health risks for children due to electromagnetic fields it is crucial to translate scientific knowledge both into adequate protection and precautionary measures for the general public and, more particularly into specific recommendations for children. It is often aimed at influencing health-related attitudes and behaviour by means of information about health affecting behaviour, health risk factors, and health promoting possibilities. Children have to be treated differently from adults in addressing their ability and willingness to modify behaviour and their competence to comprehend cognitively the sense of behavioural recommendations. Research has shown that adults can be motivated to adjust their own behaviour in order to protect their children or to be role models for their children. Hence one way to modify children's behaviour is to address the parents and care persons. Generally education in the family, the social environment and in peer groups, nursery school and at school plays an important role in forming and influencing individual behaviour. The age of the target group has also to be taken into consideration. An important question is how to deal with scientific uncertainties when expressing EMF recommendations for children. Accentuating scientific uncertainties may under certain circumstances raise risk awareness. This can be an intended effect. But the expression of scientific uncertainties can also lead to unintended consequences in parent's behaviour or even senseless dealing with the respective EMF source. The paper points out relevant aspects of risk communication regarding EMF and children and suggests how recommendations for children might be designed. PMID:21967839

Pölzl, Christiane

2011-12-01

21

EMF Responses in Farm Animals  

SciTech Connect

Relatively few studies have been performed investigating the effects of EMF exposure on farm animals. Most of those that have been described in the literature are of surveys of animals living in the vicinity of power transmission lines. Even fewer studies have been conducted in large animals under controlled laboratory conditions. Results generally provide little evidence that electric and/or magnetic fields at environmental levels (under transmission lines up to 1000 kV) affect farm animals. There is limited evidence that cows exposed to EMF may exhibit slight changes in length of estrous cycle, although associated hormones (eg. progesterone) appear to be unaffected. The effects of electric fields on development in swine (some increase in birth defects and malformations) exposed to high strength electric fields were not consistent across generations nor supported by comparable rodent studies. Finally, electrical currents and"stray voltages", parameters associated with EMF, are found on some farms above perception levels. These voltages and currents can produce behavioral changes in farm animals and may impact production or health of the animals.

Anderson, Larry E. (BATTELLE (PACIFIC NW LAB)); R Matthes, JH Bernhardt, and MH Repacholi

1999-10-19

22

Containing the costs of the EMF problem  

SciTech Connect

The uncertainty surrounding possible health effects of power-frequency electric and magnetic fields (EMF's) is fueling a costly controversy over the safety of high voltage transmission lines, neighborhood power-distribution circuits, home and office wiring, elelctrical appliances, and office equipment. Mounting public concerns are driven primarily by a number of epidemiological studies that show increased risks of cancer among populations thought to experience unusual patterns of EMF exposure. Because the scientific evidence on EMF bioeffects is both complicated and contradictory, regulatory bodies and scientific standard-setting organizations have been unable to reach consensus on prescriptive approaches to EMF risk management. Although scientific opinion varies widely about whether the EMF-cancer connection is real, public apprehension over potential EMF hazards has prompted a host of political, legal, and market reactions.

Florig, H.K. (Resources for the Future, Washington, DC (United States))

1992-07-24

23

MOF to EMF: there and back again  

Microsoft Academic Search

The OMG's Meta-Object Facility (MOF) and the open source Eclipse Modelling Framework (EMF) are two popular meta-modelling frameworks, created to meet similar (but not identical) requirements. A means of translating MOF to EMF and vice versa is required to enable the two communities to leverage one another's specifications. This paper explains the relationship between the MOF and EMF meta-models and

Anna Gerber; Kerry Raymond

2003-01-01

24

EMF: Liability, prudent avoidance, and communication  

SciTech Connect

The authors conclude that there is a growing need for utilities to be truly sensitive to public concerns about potential EMF health risks. It is not in a utility's long-term litigation interest - or other interest - to adopt a position on EMF health issues that does not fully recognize the nature and extent of the current scientific inquiry. Nor should utilities adopt a position that reads more into the EMF research than the research itself supports. Instead, the authors; experience suggests that litigation and other interests are best served by a balanced approach to EMF health and public policy issues that is open, direct, and responsive to public concerns.

Watson, T.; Warnquist, M.

1991-04-01

25

New visualization strategy to study the dynamics of surgical coagulation devices in biological tissue using absolute subsurface thermal imaging  

NASA Astrophysics Data System (ADS)

Visualisation of the thermo dynamics of surgical coagulation devices like laser, diathermy and RFA devices in tissue are essential to get better understanding about the principles of operation of these devices. Thermo cameras have the ability to measure absolute temperatures. However, the visualization of temperature fields using thermal imaging has always been limited to the surface of a medium. We have developed a new strategy to look below the surface of biological tissue by viewing through a ZincSelenide window positioned alongside a block of tissue. When exposed from above with an energy source, the temperature distribution below the surface can be observed through the window. To obtain a close-up view, the thermo camera is enhanced with special macro optics. The thermo dynamics during tissue interaction of various electro surgery modes was studied in biological tissues to obtain a better understanding of the working mechanism. Simultaneously with thermal imaging, normal close-up video footage was obtained to support the interpretation of the thermal imaging. For comparison, temperature gradients were imaged inside a transparent tissue model using color Schlieren imaging. The new subsurface thermal imaging method gives a better understanding of interaction of thermal energy of surgical devices and contributes to the safety and the optimal settings for various medical applications. However, the technique has some limitations that have to be considered. The three imaging modalities showed to be both compatible and complementary showing the pro- and cons- of each modality.

Been, Stefan L.; Verdaasdonk, Rudolf M.; Klaessens, John H. G. M.

2011-02-01

26

A Simple Demonstration of Back emf  

ERIC Educational Resources Information Center

In discussing motors, one college textbook says, "As the coil (of a motor) rotates in a magnetic field, a back emf is generated that tends to counter the emf that supplies the current." This is a true statement, but it does little to enhance student understanding of how and why it is created. In this paper, I will explain how to take students step…

Turner, Lou

2009-01-01

27

Absolute brightness measurements in the terahertz frequency range using vacuum and thermal fluctuations as references  

NASA Astrophysics Data System (ADS)

A total procedure for the terahertz wave brightness calibration using the quantum fluctuations at terahertz frequencies as a reference is formulated. An experimental proof for its theoretical background is provided. Klyshko method for the brightness calibration using spontaneous parametric down-conversion is modified, considering the case when the idler wave hits the terahertz frequency range and relative additives to the background signals induced by an external terahertz radiation can be measured both in Stokes and anti-Stokes ranges. It is shown at different temperatures that the thermal-fluctuation-induced signals have the same spectral and angular shapes, as the spontaneous parametric down-conversion signals, while the thermal-induced signal amplitudes are proportional to the number of photons in the thermal equilibrium modes.

Kitaeva, G. Kh.; Yakunin, P. V.; Kornienko, V. V.; Penin, A. N.

2014-02-01

28

Thermal conductivity of magnesium oxide from absolute, steady-state measurements  

SciTech Connect

The thermal conductivity of polycrystalline magnesium oxide has been measured over the temperature range from 400 K to 1300 K using a modified guarded-hot-plate design. Three different thicknesses of specimens having 93% of theoretical density were tested to verify the operation, accuracy, and reproducibility of the apparatus. The measured thermal conductivity ranges from 30 W {center_dot} m{sup {minus}1} {center_dot} K{sup {minus}1} down to 8 W {center_dot} m{sup {minus}1} {center_dot} K{sup {minus}1} and has an inverse-temperature functionality. The results agree well with literature values for this material.

Slifka, A.J.; Filla, B.J.; Phelps, J.M. [National Inst. of Standards and Technology, Boulder, CO (United States)

1998-07-01

29

LVI. The thermal conductivity of potassium chrome alum at temperatures below one degree absolute  

Microsoft Academic Search

An account is given of measurements of the thermal conductivity of potassium chrome alum made between 0·14° and 0·30° K., from which it is concluded that the mean free path of the phonons in the crystal is about 1\\/2 mm. In the method employed, a long single crystal of the salt, isolated from the outside world, is demagnetized to a

C. G. B. Garett

1950-01-01

30

Limitations to EMF exposure worldwide and the situation in Turkey  

Microsoft Academic Search

Most of the national and international organizations have formulated guidelines establishing limits for occupational and residential EMF exposure. ICNIRP also developed the exposure limits for EMF. The international EMF project of WHO has completed a standards database limiting exposure to EMF. From this database it can be easily seen that the public safety level E field ranges between 3 V\\/m

Nesrin SEYHAN

2003-01-01

31

Analysis of induced EMF waveforms and torque ripple in a brushless permanent magnet machine  

SciTech Connect

Permanent magnet machines with trapezoidal back EMF waveform have been the subject of several papers in the past. The simplicity in control and the absence of an absolute position sensor makes this type of motor very attractive. Idealized analysis of such a machine is simple and will result in trapezoidal or square wave back EMF waveforms depending on the assumptions made. In the case of an idealized quasi-square wave current excitation, a ripple-free torque will be obtained. The actual back EMF waveform of these machines depends on the flux density and the conductor distributions. This in turn is a function of the magnet magnetization and the stator tooth and slot structure. In applications where a fairly smooth torque is needed, these machines are made with either the stator slots or the rotor magnets skewed by one slot. This paper deals with the analysis of the back EMF waveform and of the torque ripple waveform of such a machine when the stator slots or rotor magnets are skewed by one slot. The analysis takes into consideration the actual stator conductor distribution and the effect of magnet magnetization on the back EMF waveform. An empirical formula is developed for the magnet flux density distribution which could be used for various magnetization conditions of the magnet. Experimental results are included to confirm the analytical results.

Sebastian, T.; Gangla, V. [Delphi Saginaw Steering Systems, MI (United States)] [Delphi Saginaw Steering Systems, MI (United States)

1996-01-01

32

Modeling emf, Potential Difference, and Internal Resistance  

NSDL National Science Digital Library

Through class discussion and think-pair-share questions, this activity helps students come to understand the difference between emf and potential difference in electrical circuits. These concepts are broached within the context of internal resistance of batteries.

Maier, Steven

33

Potential EMF risks continue to worry utilities  

SciTech Connect

Risks associated with possible effects of electric and magnetic fields (the EMF issue) top the list of utility executive concerns. The EMF problem defies definition but commands increasingly higher amounts of funding and attention from utilities, the US federal government, and state regulators. Recent completed studies of EMF health effects are as inconclusive as their predecessors. Some studies have shown a mild association to some kinds of cancer in some populations, but the association and effects aren't nearly enough to justify costly corrective steps, experts agree. In the first half of this year, two utility worker studies will be released. One is by EPRI at five US utilities, and the other is by Montreal researchers for utility workers in Quebec and Ontario Canada and in France. Other research covers household wiring and plumbing configurations and grounding and appliances. Utility measurements show EMF exposure may be greater from these, than from utility facilities on the other side of the meter.

Hoske, M.T.

1994-02-01

34

Radiometric modeling of mechanical draft cooling towers to assist in the extraction of their absolute temperature from remote thermal imagery  

NASA Astrophysics Data System (ADS)

Determination of the internal temperature of a mechanical draft cooling tower (MDCT) from remotely-sensed thermal imagery is important for many applications that provide input to energy-related process models. The problem of determining the temperature of an MDCT is unique due to the geometry of the tower and due to the exhausted water vapor plume. The radiance leaving the tower is dependent on the optical and thermal properties of the tower materials ( i.e., emissivity, BRDF, temperature, etc.) as well as the internal geometry of the tower. The tower radiance is then propagated through the exhaust plume and through the atmosphere to arrive at the sensor. The expelled effluent from the tower consists of a warm plume with a higher water vapor concentration than the ambient atmosphere. Given that a thermal image has been atmospherically compensated, the remaining sources of error in extracted tower temperature due to the exhausted plume and the tower geometry must be accounted for. A temperature correction factor due to these error sources is derived through the use of three-dimensional radiometric modeling. A range of values for each important parameter are modeled to create a target space (i.e. , look-up table) that predicts the internal MDCT temperature for every combination of parameter values. The look-up table provides data for the creation of a fast-running parameterized model. This model, along with user knowledge of the scene, provides a means to convert the image-derived apparent temperature into the estimated absolute temperature of an MDCT.

Montanaro, Matthew

35

Induced EMF in a coil of wire  

NSDL National Science Digital Library

Students use a simple set up consisting of a coil of wire and a magnet to visualize induced EMF. First, students move a coil of wire near a magnet and observe the voltage that results. They then experiment with moving the wire, magnet, and a second, current carrying coil. Students connect the coil to a circuit and the current from the induced EMF charges a conductor.

VU Bioengineering RET Program, School of Engineering,

36

The Absolute Isotopic Composition of Zn in Terrestrial Materials Determined Using Double Spike Thermal Ionization Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Although long suspected to be widespread in nature, until recently, little was known about the extent of the variation of the isotopic composition, or isotopic fractionation, of Zn in natural materials. During the last decade an increasing number of high precision Zn isotopic fractionation data have been reported using MC- ICP-MS (MARECHAL et al., 1999; PETIT et al., 2008; PICHAT et al., 2003), but none have been reported on an absolute scale which is essential for interlaboratory comparison of results. In this work we report sub- permil Zn fractionation in a range of natural materials relative to the internationally proposed absolute Zn isotopic reference material (? zero) (PONZEVERA et al., 2006)using the Thermal Ionization Mass Spectrometry double spike technique. Repeated double spike analysis of the laboratory standard relative to itself demonstrated a long term reproducibility of +0.006 ± 0.039 permil amu-1. The measured isotopic composition of Zn in minerals and igneous rocks SRMs was found to be the same as the proposed absolute (? zero) which makes it possible to consider the proposed absolute Zn isotopic standard as being representative of "bulk earth" Zn. A significant and consistent fractionation of ~+0.3 permil amu-1 was found in 5 sediments from a range of localities. The results obtained for metamorphic SRMs indicate that the fractionation of Zn in these rocks is the same as found in igneous rocks but are different from the Zn found in sedimentary rocks. A clay SRM sample TILL-3 appears to exhibit a consistently Zn fractionation of +0.12 ± 0.10 permil amu-1. The isotopic composition of Zn was also measured in two plant SRMs and one animal SRM sample. The fractionation of (-0.088 ± 0.070 permil amu-1) of Zn in the Rice (a C3 type plant material) sample suggested that Zn may be used to study Zn systematics in plants. The result obtained for MURST-ISS-A2 (Antarctic Krill) was +0.21 ± 0.11 permil amu-1 relative to the laboratory standard which is similar to the average Zn fractionation results of +0.281 ± 0.083 permil amu-1 obtained for marine sediments. The fractionation of Zn in seven ultra pure Zn standard materials was also measured relative to the laboratory standard and found to range from -5.11 ± 0.36 permil amu-1 for AE 10760 to +0.12 ± 0.16 permil amu-1 for Zn IRMM 10440 confirming that that significant care must be exercised in the selection of Zn isotope laboratory standards (TANIMIZU et al., 2002). A pilot study to determine the concentration and the isotopic composition of Zn in river and tap water, and a number of processed materials was also performed. The implications and applications of these results, such as on the atomic weight of Zn will be presented.

Ghidan, O. Y.; Loss, R. D.

2008-12-01

37

Thermo-emf of cadmium alloys with indium and tin  

SciTech Connect

An experimental study was made of the temperature and concentration dependences of absolute thermo-emf in binary alloys of cadmium with indium and tin throughout the entire composition range and in the high-temperature region from room temperature to 350 /sup 0/C, including the transition from the solid to the liquid state. Concentration dependences of the partial scattering sections and their derivatives with respect to conduction electron energy were found for liquid alloys of the cadmium--tin system. A tendency was noted in liquid alloys of this system toward a change in the characteristics of conduction electron interaction with the subsystem of dissolved atoms in the direction of the characteristics of free electrons after dilution of the solution.

Ivlev, V.I.; Yudin, V.A.

1987-05-01

38

Meadow street family files EMF suit  

SciTech Connect

When Arthur Bryant spoke to an electromagnetic fields (EMF) conference last March in Washington, D.C., he promised the group one thing: [open quotes]EMF [court]cases are coming.[close quotes] Last month, Bryant, executive director of Trial Lawyers for Public Justice (TLPJ), kept that promise when TLPJ filed a lawsuit in Connecticut Superior Court against Northeast Utilities (NU) and its subsidiary Connecticut Light and Power (CL P) on behalf of Melissa Bullock and her family. The Bullocks live near CL P's Meadow Street substation in Guilford, Connecticut, and TLPJ contends that 19-year-old Melissa's cancerous brain tumor was caused by EMF emanating from the substation. For ten years, TLPJ and the family claim, Melissa slept directly underneath the line from the substation that serves the Bullock home. Now they are seeking punitive and compensatory damages from NU and CL P for Melissa's condition, her mother Suzanne's emotional distress, and the lost value of their home, as well as injunctive relief that would force the companies to [open quotes]cease the emission of dangerous levels of EMF onto the plaintiff's property[close quotes] and to disclose information about the risks of EMF to the public.

Greenberger, L.S.

1992-02-15

39

Methodological approach to EMF protection standards  

NASA Astrophysics Data System (ADS)

Biological and health effects of electromagnetic fields (EMF) have been investigated for many years. Exposure standards have been developed internationally, that provide adequate protection against all known adverse effects of exposure to EMF. The guidelines developed by the International Commission on Non Ionizing Radiation Protection (ICNIRP) are widely recognized and have formed the basis for national regulations in several countries. Concerns for hypothesized, but unproven, long-term effects of chronic exposure to low-level EMFs have created a demand for precautionary measures beyond the standards for recognized, acute effects. However, such measure should be separate from exposure standards, and adopted with special care to avoid undermining the credibility of science-based guidelines, and of health protection agencies.

Vecchia, Paolo

2010-04-01

40

Another blow weakens EMF-cancer link  

SciTech Connect

This article describes recent developments in the strongest evidence linking electromagnetic field exposure to cancers. Work suggesting that low-level EMF exposure can dramatically affect the workings of the Myc gene, an oncogene implicated in a host of human cancers, has been called into doubt. Two elaborate attempts to relicate the findings (Saffer and Thurston; Hasketh) have failed completely although the orginal researcher says they have still failed to replicate her protocaol in the original experiment exactly. She and her co-researcher (Goodman and Henderson) continue to report positive links between EMF and Myc RNA increases.

Taubes, G.

1995-09-29

41

EMF Genes Maintain Vegetative Development by Repressing the Flower Program in Arabidopsis  

Microsoft Academic Search

The EMBRYONIC FLOWER ( EMF ) genes EMF1 and EMF2 are required to maintain vegetative development and repress flower development. EMF1 encodes a putative transcriptional regulator, and EMF2 encodes a Polycomb group protein ho- molog. We examined expression profiles of emf mutants using GeneChip technology. The high degree of overlap in expres- sion changes from the wild type among the

Yong-Hwan Moon; Lingjing Chen; Hur-Song Chang; Tong Zhu; Daniel M. Maffeo; Z. Renee Sung

2003-01-01

42

Helminth associated hypereosinophilia and tropical endomyocardial fibrosis (EMF) in Nigeria  

Microsoft Academic Search

There should be a recognisable trend between the incidence of hypereosinophilia and the duration of tropical endomyocardial fibrosis (EMF), if the hypothesis, that EMF is the burnt out phase of eosinophil associated heart disease, is correct. We tested this hypothesis in a prospective study of 89 consecutive EMF cases over an 18 year period at two Nigerian locations (Ife in

J. J Andy; P. O Ogunowo; N. A Akpan; C. O Odigwe; I. A Ekanem; R. A Esin

1998-01-01

43

EMF, an Arabidopsis Gene Required for Vegetative Shoot Development  

Microsoft Academic Search

In higher plants, the transition from the vegetative to the reproductive state in the shoot meristem initiates flowering. To study this floral transition, a constitutively flowering mutant of Arabidopsis thaliana ecotype columbia, embryonic flower (emf), was characterized. No vegetative shoots were produced from emf embryos or calli; the shoot apical meristems (SAMs) in the emf embryos were altered compared to

Z. R. Sung; A. Belachew; Bai Shunong; R. Bertrand-Garcia

1992-01-01

44

Containing the costs of the EMF problem  

Microsoft Academic Search

The uncertainty surrounding possible health effects of power-frequency electric and magnetic fields (EMF's) is fueling a costly controversy over the safety of high voltage transmission lines, neighborhood power-distribution circuits, home and office wiring, elelctrical appliances, and office equipment. Mounting public concerns are driven primarily by a number of epidemiological studies that show increased risks of cancer among populations thought to

H. Florig

1992-01-01

45

Development of an EMF Measurements Database, EMF Rapid Program, Project Number 5, Interim Report: April 1995-December 1996.  

National Technical Information Service (NTIS)

The EMF Measurements Database project is being implemented by T. Dan Bracken, Inc. as part of the EMF Research and Public Information Dissemination (EMF RAPID) Program. The Database is a collection of data sets that relate to measurement of electric and/o...

I. T. Dan Bracken

1998-01-01

46

Effect of EMF on minimum cost power transmission  

SciTech Connect

The concern about electromagnetic field (EMF) effects on human health has heightened public awareness of overhead transmission lines planning and operation. The objective of this paper is to study the effect of EMF constraints on optimal power generation scheduling. This study considers reducing EMF levels associated with critical transmission lines by redistributing the scheduled power generation, while maintaining the minimum operation cost as an objective. The EMF constraints are given in terms of control variables and fuzzy sets are utilized to model the tradeoff between minimizing the objective function and satisfying EMF constraints. Numerical results for the application of the proposed approach to test systems are discussed.

Abdul-Rahman, K.H.; Shahidehpour, S.M.; Deeb, N.I. [Illinois Inst. of Tech., Chicago, IL (United States)] [Illinois Inst. of Tech., Chicago, IL (United States)

1995-02-01

47

Designing EMF experiments: What is required to characterize ``exposure``?  

SciTech Connect

Anyone who has attempted to organize and synthesize the results of research on biological effects of electric and magnetic fields (EMF) has experienced frustration when trying to evaluate the comparability of EMF exposures among separate studies. Reporting of exposure characteristics is often incomplete, and some investigators focus on particular nuances of exposure, which in other laboratories go unrecorded because they are not regarded as important. The obstacles encountered when comparing studies, when designing replication studies, and when evaluating research proposals could be reduced were a more standardized approach taken in describing EMF exposure. To this end, a numerical listing of 18 separate parameters important to EMF exposure characterization is proposed. Although the goal of this list is primarily to expedite the description of EMF exposure, references are provided to examples of EMF exposures and to detailed discussions of EMF exposure systems.

Valberg, P.A. [Gradient Corp., Cambridge, MA (United States)]|[Harvard School of Public Health, Boston, MA (United States). Dept. of Environmental Health

1995-12-31

48

Absolutely relativity  

NASA Astrophysics Data System (ADS)

The light speed constancy is proved here and then it is not a principle suppose it is a proposition proved absolutely based on the Galilean transformation and simultaneity and this is a book full from new discoveries along the absolutely proof for Lorentz transformation. Even in a page I have proved Lorentz transformation by the brawer constant point based on the Galilean transformation until to show easily it is possible to generate absolutely relativity and this is not ether theorem suppose we are upon the new discoveries all mathematical and complete, not a theory.

Lutephy, Mohsen

2012-03-01

49

Changes in gene expression following EMF exposure  

SciTech Connect

Experiments were designed to examine the effects of electromagnetic field (EMF) exposure on specific gene expression, an effect that can be deleterious, beneficial, or neutral, depending on the long-term consequences; however, the proof of a reproducible, quantitative biological effect (such as change in gene expression) will lead to latter experiments aimed at determining the relative contribution of these changes to cellular consequences. Past work by ourselves and by others has shown that measures of gene expression are extremely sensitive indicators of the cellular and biological effects of ionizing radiation, with transcriptional changes being detected by exposure of cells to doses of {gamma}-rays as low as 0.01 cGy that have no pronounced cellular consequences. On the basis of this work, the authors hypothesized that measures of gene expression will be equally sensitive to EMF effects on cells.

Woloschak, G.E.; Paunesku, T.; Chang-Liu, C.M. [Argonne National Lab., IL (United States). Center for Mechanistic Biology and Biotechnology; Loberg, L.; Gauger, J.; McCormick, D. [IIT Research Inst., Chicago, IL (United States)

1997-10-01

50

No link yet, but EMF studies continue  

SciTech Connect

The Edison Electric Institute (EEI) reports that the electric utility industry spent $10 million in 1994 on electric and magnetic fields (EMF) research conducted by the Electric Power Research Institute based in Palo Alto, California. To date, the electric utility industry has contributed close to $80 million since the 1970s. The U.S. Department of Energy (DOE) will administer an interagency EMF program in 1995 called RAPID (the Research and Public Information Dissemination program). It is a five-year, $65 million effort by DOE and the National Institute of Environmental Health Sciences (NIEHS). Some research elements are already under way. Congress has appropriated $8 million for the program in fiscal year (FY) `95. EEI member companies will contribute $4 million for FY`95 (compared to $3.2 million in FY`94) and are committed to contributing $16.5 million over the next five years.

NONE

1995-05-01

51

Theoretical Comparison of Motional and Transformer EMF Device Damping Efficiency  

NASA Astrophysics Data System (ADS)

In this paper, theoretical comparison between electromagnetic dampers based on a “motional emf” and “transformer emf” design is presented. Transformer emf devices are based on the generation of emf in a stationary circuit, in which the emf is generated by a time-varying magnetic field linking the circuit. Motional emf devices are based on the generation of emf due to a moving conductor within a stationary magnetic field. Both of these designs can be used as damping elements for applications such as semi-active and regenerative vehicle suspension systems. The findings herein are provided so as to evaluate the most efficient device for such applications. The analysis consists of comparing the damping coefficient of the electromagnetic devices for a given magnetic field and given volume of conducting material. It has been found that for a limited range of dimensions, the transformer emf devices can be more then 1·2 times as efficient as the motional emf devices. However, for most realistic situations, motional emf devices will have the highest efficiency.

GRAVES, K. E.; TONCICH, D.; IOVENITTI, P. G.

2000-06-01

52

Defending against EMF property devaluation cases  

SciTech Connect

Late last year, New York`s highest court, the Court of Appeals, ruled that the owner of property adjacent to a utility`s high-power electrical transmission lines could seek damages for a decrease in the market value of the property caused by the fear that the power lines might cause cancer, even if such a fear was not medically or scientifically reasonable. That decision has already begun to change the outlook on electromagnetic field (EMF) litigation for utilities.

Brandon, G. [Milbank, Tweed, Hadley & McCloy, New York, NY (United States)

1995-02-01

53

Development of an EMF Measurments Database, EMF Rapid Program, Project #5, Interim Report: April 1995-December 1996  

SciTech Connect

The EMF Measurements Database project is being implemented by T. Dan Bracken, Inc. as part of the EMF Research and Public Information Dissemination (EMF RAPID) Program. The Database is a collection of data sets that relate to measurement of electric and/or magnetic fields. This report describes activities during the period January 1997 to March 1998. Primary goals for the EMF Measurements Database are to develop a database structure that can accommodate the diversity of EMF data sets, provide guidance for production of future EMF data sets, and serve as an accessible repository of EMF measurement data. Specific objectives of the EMF Measurements Database are: o to presewe study descriptions, results and data; o to provide readily accessible, well-documented data; and - o to facilitate communication among researchers. In addition, the EMF Measurements Database will encourage additional analysis of existing data sets, facilitate analysis of data from multiple projects, support design of new studies, and permit future issues in EMF exposure assessment to be addressed with existing data. Preservation of study descriptions and data is accomplished with a formal, but open, structure. Specifications have been developed for the various elements of the database. Each data set in the database is formally described by a metadata file. The structured metadata file describes the origin, development, logical and physical structure, and distribution mechanism for each data set. The metadata for each data set is generated according to a specification developed for the EMF Measurements Database. The actual measurement data is contained in data products for each data set. The number and type of data product will vary by data set. Most of the data products available from the EMF Measurements Database can be downloaded from an Internet site. For some data sets, the data products will be maintained by other patties who may have their own access procedures.

T. Dan Bracken, Inc.

1998-03-01

54

A handbook for communicating potential EMF (electromagnetic fields) risks  

Microsoft Academic Search

This handbook is designed to help utility industry personnel in communicating with the public about issues related to potential health risks associated with electromagnetic fields (EMF). The handbook is intended to serve as a practical guide for the development of risk communications. The handbook has been prepared in a format that will facilitate step-by-step preparation of EMF risk communication materials

J. Kadvany; L. Merkhofer

1990-01-01

55

60 Hz EMF health effects-a scientific uncertainty  

Microsoft Academic Search

Extensive epidemiological and laboratory research has been conducted over the last 15 years on the biological and health consequences of exposure to ELF EMFs. Some epidemiological studies have found weak associations between exposure to power-frequency EMFs and some forms of cancer, such as leukemia; while other studies have failed to find such associations. The primary limitation with most epidemiological studies

Stephan P. Albert Bren

1995-01-01

56

Appearance of thermochemical emf in some conducting materials  

Microsoft Academic Search

The appearance of an emf in conductors when they are heated is described by the Seebeck and Thompson effects. If some part of the surface of a conductor is covered by a pyrotechnical material and ignited, then while the pyrotechnical material is burning and after it has burned, an emf arises at the ends of the conductor. The direction of

Y. S. Petrov; V. V. Maslikhov; V. D. Shcheglov

1983-01-01

57

Litigating fear: electrical and magnetic fields (EMF) and the law  

Microsoft Academic Search

A large number of persons in the United States and Europe believe that EMF causes human illness. These illnesses include childhood leukemia, other cancers, high blood pressure, the aggravation of other diseases, and electrical sensitivity syndrome. EMF has become a legal issue as people seek compensation for alleged injuries and try to have power lines relocated away from their homes.

1997-01-01

58

Designing EMF experiments: What is required to characterize ``exposure``?  

Microsoft Academic Search

Anyone who has attempted to organize and synthesize the results of research on biological effects of electric and magnetic fields (EMF) has experienced frustration when trying to evaluate the comparability of EMF exposures among separate studies. Reporting of exposure characteristics is often incomplete, and some investigators focus on particular nuances of exposure, which in other laboratories go unrecorded because they

Peter A. Valberg

1995-01-01

59

Dynamic Properties of Back-emf Based Sensorless Drives  

Microsoft Academic Search

This paper investigates the speed sensitivity of back-emf based sensorless techniques for PM machines. The eigenvalues of the back-emf based estimation are speed dependent leading to performance degradation including reduced command tracking and disturbance rejection. At low speeds, it is shown that instability occur. The paper analyzes an operating point model of the permanent magnet synchronous machine for both sensor-

L. A. de S Ribeiro; M. C. Harke; R. D. Lorenz

2006-01-01

60

Precise Semantics of EMF Model Transformations by Graph Transformation  

Microsoft Academic Search

Model transformation is one of the key activities in model-driven soft- ware development. An increasingly popular technology to define modeling lan- guages is provided by the Eclipse Modeling Framework (EMF). Several EMF model transformation approaches have been developed, focusing on different transformation aspects. To validate model transformations wrt. functional behav- ior and correctness, a formal foundation is needed. In this

Enrico Biermann; Claudia Ermel; Gabriele Taentzer

2008-01-01

61

Variability in EMF permittivity values: implications for SAR calculations  

Microsoft Academic Search

Digital anatomical models of man and animals are available for use in numerical calculations to predict electromagnetic field (EMF)-induced specific absorption rate (SAR) values. To use these models, permittivity values are assigned to the various tissues for the EMF frequencies of interest. There is, as yet, no consensus on what are the best permittivity data. This study analyzed the variability

William D. Hurt; John M. Ziriax; Patrick A. Mason

2000-01-01

62

Development of an EMF Measurements Database, EMF Rapid Program, Project #5, Interim Report: April 1995-December 1996  

SciTech Connect

The EMF measurement data sets in existence today were compiled with varying goals and techniques. Consequently, they have different information content as well as varying logical and physical structure. Future studies will continue to pursue varying goals and utilize techniques that cannot be known in advance. Primary goals for the EMF Measurements Database developed under the Department of Energy EMF RAPID Program are to develop a database structure that can accommodate the diversity of EMF data sets, provide guidance for production of future EMF data sets, and serve as an accessible repository of EMF measurement data. Specific objectives of the EMF Measurements Database are: o to preserve study descriptions, results and data; o to provide readily accessible, well-documented data; and o to facilitate communication among researchers. In addition, the EMF Measurements Database will encourage additional analysis of existing data sets, facilitate analysis of data from multiple projects, support design of new studies, and permit future issues in EMF exposure assessment to be addressed with existing data. Preservation of study descriptions and data is accomplished with a formal, but open, structure. Specifications have been developed for the various elements of the database. Each data set in the database is formally described by a metadata file. The structured metadata file describes the origin, development, logical and physical structure and distribution mechanism for each data set. The metadata for each data set is generated according to a specification developed for the EMF Measurements Database. The actual measurement data is contained in data Products for each data set. The number and type of data product will vary by data set. Most of the data products in the possession of the EMF Measurements Database are available for download from an Internet site. For some data sets, the data products will be maintained by other parties who may have their own access procedures. In addition, data set contributors or users can provide reports that describe results of the study and analysis of the data with text and figures. Guidelines have been developed for preparation of reports. Access to the EMF Measurements Database is provided via an Internet site (http://www.emf-data. erg). The site provides descriptive information in a home page, . . access to data products with a file transfer protocol (ftp) address, and links to other EMF-related sites.

T. Dan Bracken, Inc.

1997-04-01

63

Helminth associated hypereosinophilia and tropical endomyocardial fibrosis (EMF) in Nigeria.  

PubMed

There should be a recognisable trend between the incidence of hypereosinophilia and the duration of tropical endomyocardial fibrosis (EMF), if the hypothesis, that EMF is the burnt out phase of eosinophil associated heart disease, is correct. We tested this hypothesis in a prospective study of 89 consecutive EMF cases over an 18 year period at two Nigerian locations (Ife in South West and Calabar in South East). We carefully dated the duration of EMF symptoms at first presentation and screened for hypereosinophilia (eosinophilia > or = 1500/mm3), and their causes. When no cause was identified for hypereosinophilia we gave a therapeutic trial with diethylcarbamazine to the patients. An eosinophil count > or = 1000/mm3 was recorded in 80% of 24 cases seen within 6 months; 55% of 46 cases seen 0-24 months; 54% of 18 cases seen 25-48 months and 21% of 25 cases seen more than 49 months of onset of symptoms: while the respective distribution of eosinophil count > or = 1500/mm3 for similar periods were 66, 44, 27 and 21%. This reflects a highly significant (P < 0.001) inverse relationship between hypereosinophilia and the duration of EMF and strengthens the concept that EMF (without eosinophilia) represents the late stage of eosinophilic heart disease. The localisation of endemic EMF to the low-lying tropical rain forest Zone and its predominant occurrence among rural dwellers and farmers suggest a vector borne etiologic agent. Microfilaria was the most likely cause of hypereosinophilia in the cases presented. PMID:9588233

Andy, J J; Ogunowo, P O; Akpan, N A; Odigwe, C O; Ekanem, I A; Esin, R A

1998-05-01

64

The first photometric study and an estimation of the absolute elements of the misclassified poor thermal contact binary system NSV 3744 Gem  

NASA Astrophysics Data System (ADS)

We present the first CCD Johnson-Cousins V and Rc light curves of the contact binary NSV 3744 obtained in 5 nights in January-March 2012. These observations confirm the short period (P = 0.520 days) of the system. The presented light curves are analyzed simultaneously by means of the 2003 version of the Wilson-Devinney (WD) code. A grid of solutions for several fixed values of the mass ratio was calculated. The best fitting possible is for a mass ratio q = 0.379, a degree of contact f = 16.6% an orbital inclination i=81.1° and transit primary minimum. It was found that NSV 3744 was misclassified. Despite the fact that it shows a light curve of a ? Lyrae type eclipsing binary star, our analysis leads to an A-subtype W Ursae Majoris contact binary system in poor thermal contact; the difference between the mean temperatures of the components is about 1650 K. The system seems to be another member of the class of poorly understood close binaries in or near geometrical contact but far from thermal contact. The absolute dimensions are estimated and its dynamical evolution is inferred.

Martignoni, M.; Acerbi, F.; Barani, C.

2014-01-01

65

Cryogenic, Absolute, High Pressure Sensor  

NASA Technical Reports Server (NTRS)

A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

2001-01-01

66

The Principle of Measuring Differential Thermo EMF in the Device \\  

Microsoft Academic Search

For mass sorting out of articles according to steel types the possibility of thermo-emf control in a certain range is provided. For this purpose comparator CI with controlled threshold of wearing is used in the diagram.

V. V. Denisov; L. A. Soldatov; A. S. Tsekhanovsky

2005-01-01

67

EMF in its infancy: A call for openness  

SciTech Connect

The author feels we are still in the awareness stage of EMF; the public is, for the most part, receptive to information and there is no real consus. He notes that it is this that shapes the approach of his company, PSI Energy, to public concerns about EMF: (1) when someone calls about EMF, they may just have heard about the subject; (2) someone concerned about EMF may or may not turn immediately to their local utility for information; and (3) PSI feels that, wherever a person turns, he or she should get good, factual information that permits an informed judgment. Those beliefs led directly to an important part of PSI's communications strategy: networking. Basically, networking is getting the information reprints, brochures, etc. - into the hands of the media, association's, state boards of health, etc. so that point (3) above can be handled for an anxious inquirer.

Norris, R.E.

1991-05-01

68

EMF-cancer links: Yes, no, and maybe  

SciTech Connect

The controversy over whether or not low-level electromagnetic fields (EMF) can cause cancer has been smoldering for 15 years. This month it got a little hotter -- but there's still more smoke than fire. At the beginning of October, writer and EMF gadfly Paul Brodeur brought out his latest book exposing a purported EMF-cancer connection, entitled The Great Power-line Cover-up. Right on his heels, however, on 9 October, the British Medical Journal weighed in with two serious scientific assessments of the cancer risk. Unfortunately for those who long for a conclusive answer, one study found only a slight positive association between EMF and cancer, and the other found no link at all. Together the studies [open quotes]artfully provide middle-of-the-road type of evidence,[close quotes] says Dimitrios Trichopoulos, chairman of the epidemiology department at the Harvard School of Public Health.

Taubes, G.

1993-10-29

69

Utilities feel weight of burden caused by EMF fears  

SciTech Connect

Studies on the effects of electromagnetic fields (EMF)on human health have been conducted for more than 20 years. None have categorically established or eliminated any connection between EMF and adverse health effects. Nonetheless, 96% of the risk managers working in the utility sector view EMF as an over-riding concern. Public concern over EMF has erupted into legal, as well as regulatory, actions. To date, some utilities have had lawsuits brought against them by customers who claim they developed cancer as a result of nearby high-voltage transmission lines. What`s more, a small handfull of cities have adopted ordinances that specifically limit where and how utilities handle the placement of their transmission lines.

Warkentin, D.

1995-10-01

70

INDUCED EMF AND DIELECTRIC STRENGTH IN X-IRRADIATED PVC  

Microsoft Academic Search

The nature and behavior of induced emf and dielectric strength were ; studied for x irradiated poly(vinyl chloride). PVC samples were placed in a ; specially designed chamber and x irradiated at intensities of 50,000 to 150,000 r\\/; min in doses of 10 to 10⁶r at a sample temperature of 20 to 100 deg C. The ; induced emf (

V. D. Kuchin; A. K. Shastova

1962-01-01

71

Evaluation of Electromagnetic Fields (EMF) in Schools in Cyprus  

Microsoft Academic Search

Summary  This paper deals with the evaluation of Extremely Low Frequency (ELF) Electromagnetic Fields (EMF) produced by high tension\\u000a wires on pylons and substations, which were preliminarily investigated by taking measurements in schools (on behalf of the\\u000a Environmental Committee of Limassol). It publicizes the level of EMF from the above sources and makes an attempt to compare\\u000a them with various exposure

Andreas Neocleous

2005-01-01

72

Development of an EMF Measurements Database, EMF Rapid Program, Project Number 5, Interim Report: April 1995-December 1996.  

National Technical Information Service (NTIS)

The EMF measurement data sets in existence today were compiled with varying goals and techniques. Consequently, they have different information content as well as varying logical and physical structure. Future studies will continue to pursue varying goals...

I. T. Dan Bracken

1997-01-01

73

Toward a sensible EMF policy: One utility's approach  

SciTech Connect

Over the past three years, the Los Angeles Department of Water and Power (LADWP) has developed an open, proactive approach to address the electromagnetic fields (EMF) issue. Many things gave impetus to this approach: the public's increasing concern about possible health effects associated with EMF; litigation and other difficulties utilities experience when attempting to construct electric facilities; and media coverage fueling public concern about the issue. For LADWP, management of this issue involves a communications and a policy development effort, both of them significant. As an integral part of managing this issue, LADWP has taken steps to reduce fields associated with new projects on a case-by-case basis where economically justified, and supported EMF research, including support for a national EMF research program. Also, LADWP continues its full support for and participation in the Electric Power Research Institute's (EPRI) EMF research program. In the discussion here, references to EPRI reports, bulletins, and technical papers have intentionally been excluded, since their inclusion would overwhelm the footnotes to this paper. Finally, LADWP has purposefully sought additional guidance from other individuals and public policy agencies, many of whose works are cited here.

Palk, B.V. (Los Angeles Dept. of Water and Power, CA (USA))

1991-04-01

74

Review of literature and studies on electro magnetic fields (EMF) generated by undersea power cables and associated influence on marine organisms  

Microsoft Academic Search

The objective of this paper is to provide a comprehensive review of the available literature on EMF transmitted by submarine cables and the effects, if any, on marine organisms to assess the possible implications for environmental permitting of submarine power cables, such as those required for offshore wind, wave, tidal and Ocean Thermal Energy Conversion (OTEC) projects. The potential for

Todd Switzer; Dallas Meggitt

2010-01-01

75

Reproductive and developmental effects of EMF in vertebrate animal models.  

PubMed

This paper reviews the literature data on the effects of electromagnetic fields (EMF), in the reproductive organs as well as in prenatal and postnatal development of vertebrate animals. Review articles which have been published till 2001, regarding the reproductive and developmental effects of the entire range of frequency of electromagnetic fields, were surveyed. Experimental studies which were published from 2001 onwards were summarized. Special focus on the effects of radiofrequencies related to mobile communication in the above mentioned topics has been made. According to the majority of the investigations, no strong effects resulted regarding the exposure to EMF of mobile telephony in the animal reproduction and development. However further research should be done in order to clarify many unknown aspects of the impact of EMF in the living organisms. PMID:19272761

Pourlis, Aris F

2009-08-01

76

EMF health effects research: Problems and current status  

SciTech Connect

The author describes some of the current generation of research, focusing particularly on that being sponsored by the Electric Power Research Institute (EPRI). The central goal of the research program is to answer the question of whether threats to human health result from exposure to electric and magnetic fields. Several related questions are examined: Is there any epidemiological evidence of risk to those who are exposed What are the sources of exposure to EMF, and who is exposed What effects, if any, occur in laboratory animals exposed What is the biologically important parameter, or 'dose' of EMF exposure How is exposure best estimated What effects, if any, occur in laboratory animals exposed to EMF If there are effects of exposure in cells or tissues, where in the cell does that interaction occur The author describes current research to answer these questions.

Sagan, L.A. (Environment Division of the Electric Power Research Inst., Palo Alto, CA (United States))

1990-07-19

77

Electromagnetic fields (EMF): do they play a role in children's environmental health (CEH)?  

PubMed

Possible adverse health effects of exposure to electric, magnetic and electromagnetic fields (EMF), and especially the question of whether there exists a special vulnerability of children, have been a much discussed topic during the last two decades. Static fields produce health effects only in very rare and exceptional circumstances at extremely high field intensities. As for low-frequency EMF, the results of epidemiological research with respect to childhood leukaemia prompted the International Agency for Research on Cancer (IARC) in 2001 to classify these fields as "possibly carcinogenic to humans". Current hypotheses on the mechanism of such action are presented. The effect, if existent, appears to be not very important in relation to established other causes of childhood leukaemia. High-frequency EMF, as used in mobile and wireless communication (mobile telephony according to the GSM and UMTS standard, cordless DECT phones, wireless local area networks (WLAN), Bluetooth) and since many decades also in radio and television technology, are practically omnipresent. At high intensities, the generation of heat is the principal effect. Current guidelines, limits and regulations prevent any such effect. Mobile phone calls may, in certain circumstances, lead to local exposures close to limit values. Base stations typically produce exposures lower by 2-5 magnitudes. The discussion centres on the so-called non-thermal effects, which are supposedly occurring at field intensities, which are by orders of magnitude lower than those responsible for thermal effects. The reproducibility of these effects is usually poor, and no physiologic or pathogenic mechanism, so far, has been found to explain the alleged effects. Equally, epidemiologic studies have not furnished clear and reproducible data as arguments for negative health effects. Final results of the INTERPHONE study on the risk of brain tumours, acoustic neurinoma and parotid gland tumours associated with the use of mobile phones will be soon available. Preliminary results do not seem to indicate a substantial increase in risk. There are presently no scientific data supporting the concept of a special vulnerability of children and adolescents to high-frequency EMF, even if the usual caveats (developing organisms and structures may be more vulnerable, decades of life to come) are considered. The concept of precautionary measures adapted to such concerns is critically discussed. PMID:17765660

Otto, Matthias; von Mühlendahl, Karl Ernst

2007-10-01

78

Assessment of the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields (EMFs).  

National Technical Information Service (NTIS)

This report results from a contract tasking Russian Academy of Sciences as follows: Because of the widespread increase in man-made sources of electromagnetic fields (EMFs), including high peak-power pulsed EMF (HPPP EMF), it has become important to study ...

N. Chemeris

2003-01-01

79

ELECTROMAGNETIC FIELDS (EMF) FOR SOIL PEST CONTROL AS A MeBr ALTERNATIVE: EFFICACY AND TECHNOLOGY  

Microsoft Academic Search

EffectivenessEfficacy: The potential value of electromagnetic fields (EMF) in agriculture was recognized nearly 60 years ago by Ark and Perry ( (2). In the intervening years EMF has been used for devitalization of seeds ( 1113), pasteurization of raw milk ( 810), control of rice weevils (1012), control of weeds (57), and control of nematode populations (911). That EMF exposure

P. Baugh; E. Medress; R. Wayland; F. Davis; P Lemahieu; L. Vincent

80

Improved direct back EMF detection for sensorless brushless DC (BLDC) motor drives  

Microsoft Academic Search

Improved back EMF detection circuits for low voltage\\/low speed and high voltage sensorless BLDC motor drives are presented in this paper. The improvements are based on the direct back EMF sensing method from our previous research work described in reference, which describes a technique for directly extracting phase back EMF information without the need to sense or re-construct the motor

Jianwen Shao; Dennis Nolan; Thomas Hopkins

2003-01-01

81

NEWS AND INFORMATION: Classification of EMFs from California  

Microsoft Academic Search

California Department Of Health Services has now released the `fourth and final' draft of its `Evaluation of the possible risks from electric and magnetic fields (EMFs) from power lines, internal wiring, electrical occupations and appliances'. The third draft was released for public comment in 2001. The main conclusion is expressed thus: `To one degree or another all three of the

John Swanson

2002-01-01

82

A precautionary tale: the British response to cell phone EMF  

Microsoft Academic Search

The UK led the campaign for precautionary responses to cell phone EMF. The experience which informed this approach was BSE, a disease that originated and had greatest impact in the UK. Unsurprisingly, British politicians have responded even more directly than the EU to the cell phone issue, seeking to prove that they have \\

Adam Burgess

2002-01-01

83

Integrated analysis software for grounding, EMF, and EMI  

Microsoft Academic Search

The current distribution, electromagnetics, grounding, and soil structure analysis (CDEGS) software package for studying problems that involve power system electromagnetic fields (EMFs), electromagnetic interference (EMI), and grounding is described. This package includes three input processors, six engineering applications modules, and six output processors. The relationship between these modules and processors is illustrated. A case study of the inductive interference between

F. P. Dawalibi; F. Donoso

1993-01-01

84

Seattle city light wins EMF lawsuit brought by worker  

SciTech Connect

Ruling consistent with similar lawsuit outcomes. A Washington state workers` compensation appeals board, in upholding an earlier state agency decision, has ruled that electric and magnetic fields (EMF) did not cause a Seattle City Light worker`s leukemia. The outcome of the case, Pilisuk vs. Seattle City Light, appears to fall in line with decisions in other, similar EMF personal injury lawsuits against electric utilities. Robert Pilisuk, 44, an apprentice and electrician-constructor for Seattle City Light for seven years, died five years ago as a result of acute lymphocytic leukemia. {open_quotes}This was the first thorough examination of the large body of EMF studies by a workers` compensation system,{close_quotes} said Betty Ngan, Seattle assistant city attorney. {open_quotes}The board`s decision is based on the extensive record of testimony taken and an exhaustive review of the studies. The result of this appeal process reflects the state of the science, that there is no proven cause-and -effect relationship between EMF and health effects.{close_quotes}

Warkentin, D. [ed.

1995-01-01

85

EMF interference detection utilizing the recording feature of cardiac pacemakers  

Microsoft Academic Search

Electromagnetic (EMF) interference with cardiac pacemakers may occur in various work environments. In the case of interfering external signals, the pacemaker may misinterpret the signal as a heart-related problem and initiate treatment procedures unnecessarily. We evaluated the applicability of the interference recording feature of cardiac pacemakers to identify the interfering sources. The pacemakers were exposed to a wide variety of

Tommi Alanko; Maria Tiikkaja; Harri Lindholm; Maila Hietanen

2011-01-01

86

Effects of an ELF (50 Hz, 1 mT) electromagnetic field (EMF) on concentration in visual attention, perception and memory including effects of EMF sensitivity  

Microsoft Academic Search

To investigate psychological effects of an extremely low frequency (ELF)-electromagnetic field (EMF), an experiment with three conditions was designed. EMF field of 50 Hz and 1 mT accompanied by 45 dB SPL noise (EMF+noise), noise, and control. A group of 66 subjects (Ss) participated in the control and in one of the experimental conditions. The sequence of conditions (expositions) was

Michael Trimmel; Elke Schweiger

1998-01-01

87

Exposure assessment for power frequency electric and magnetic fields (EMF) and its application to epidemiologic studies  

SciTech Connect

Epidemiologic studies suggesting possible health effects associated with exposure to electric and magnetic fields (EMF) from the transmission, distribution, and use of electricity have motivated increased interest in and attention to EMF exposure assessment. The result has been new instruments, measurement approaches, and exposure models that can improve on what has been a weakness in past epidemiologic studies, namely EMF exposure assessment. This paper presents a status report on EMF exposure assessment that emphasizes the need for incorporation of these advances in future studies. Several factors are identified that make the assignment of contemporary or retrospective EMF exposures potentially more difficult than for other environmental agents. These include: EMF is not generally detectable by humans, exposure scenarios for EMF are generally not memorable, there is no clear mechanism for EMF effects, and the pervasive nature of EMF in an industrialized society makes identification of a low-exposure group difficult. Elements of study design that are impacted by the nature of EMF exposures include: sampling and measurement strategies, summary measures of exposure, and the choice of surrogate and/or models of exposure. Consideration of these exposure assessment issues and incorporation of recent advances can improve the overall quality of epidemiologic studies with an EMF exposure component. 41 refs.

Bracken, T.D.; Kheifets, L.I.; Sussman, S.S. (T. Dan Bracken, Inc., Portland, OR (United States))

1993-01-01

88

Absolute Theory of Relativity  

NASA Astrophysics Data System (ADS)

We redo Einstein's thought experiment with atomic clocks from the Special Theory of Relativity. Herein we consider an absolute time and an absolute space but no ultimate speed, and we call it Absolute Theory of Relativity (ATR). Our ATR is free from time dilation, space contraction, relative simultaneity, and relativistic paradoxes.

Smarandache, Florentin

2012-03-01

89

Absolute compression test  

Microsoft Academic Search

This patent describes a method for measuring the absolute compression of each cylinder in an internal combustion engine having known ideal performance parameters and consists of the following steps: sensing the absolute angular speed of the crankshaft of an engine during at least one noncombustive engine cycle; relating particular subcyclic absolute speed variations to particular cylinders; calculating the work of

Timmerman

1986-01-01

90

Determination of EMF influence on a human exposed to EMF - modeling and methodology.  

PubMed

(Full text is available at http://www.manu.edu.mk/prilozi). The wide use of electric energy in every segment of everyday living demands specific attention be paid to investigations connected with biological effects from the influence of electromagnetic fields on humans and the environment. Investigations connected with electromagnetic influence assessment on human health emphasize the influences of electromagnetic fields in a wide frequency range. Here, the interest in knowing the mechanisms of these interactions and ways of determining them is obvious. The parameters and quantities that describe such influence depend on the frequency of the electromagnetic field source that underlines the importance of their appropriate definition. Induced currents and charges as well as electric field distribution, or SAR, are quantities that represent this influence. Their determination is important for the formulation of norms and standards for human protection from exposure to electromagnetic fields. In this paper, a developed procedure for the determination of electric field distribution in the human body when exposed to EMF influence is presented. Several issues emerge in the course of this, such as finding representative parameters for problem description, modeling of the incident field source, which is obvious in various forms and in a wide frequency range, modeling of the human body, which is complex in geometric aspect and has a wide range of electric characteristics in its parts, developing an appropriate calculation methodology and a suitable presentation of the results. Modeling the incident field form and the human body are in direct correlation with the calculation method developed for determining the electric field distribution. Developed methodology enables the electric field in the humans to be determined, and other parameters such as SAR to be calculated. Having those values, we can discuss the biological effects on humans from such exposure. Key words: Electromagnetic field, electromagnetic influence, human model, induced electric field, SAR. PMID:21258285

Ololoska, L; Janev, Lj; Loskovska, S

2010-12-01

91

Transparent Democratic Foresight Strategies in the California EMF Program.  

PubMed

A California Department of Health Services program dealt with possible health effects from Electric and Magnetic Fields (EMF) from power lines. With the advice of stakeholders, and well before any risk determinations were made, transparent policy analyses about the power grid and schools asked the question, "How confident must one be of how big an effect before one would adopt cheap or expensive EMF avoidance measures?" A risk evaluation was carried out with features that promoted transparency. It was formatted to provide a policy-neutral "degree of certainty of causality" to adherents of utilitarian, environmental justice, and libertarian policy frameworks. Though the program had many features advocated by adherents of the precautionary principle, it might be better characterized as following "Transparent Democratic Foresight Strategies," since no single principle justifies the strategies used in this participatory program, and it examined the pros and cons of options but made no recommendations, precautionary or otherwise. PMID:12576535

Neutra, Raymond Richard; Delpizzo, Vincent

2002-01-01

92

Medical practitioners and electromagnetic fields (EMF): Testing their concern  

NASA Astrophysics Data System (ADS)

Health and environment (H&E) crises proliferate. In some cases, medical practitioners are involved. Legitimate as concerns social issues, they are often invited to contribute to local discussions. More recently, medical doctors (MDs) have organized themselves within local then national non-governmental organizations (NGOs). Close to citizens in issues concerning health, they are increasingly questioned by their patients on various other issues, including electromagnetic fields (EMF). Research has shown, however, that their knowledge about H&E issues is poor, although their opinions carry weight. In view of these previous studies, it appeared to be useful to conduct a quantitative survey of MDs to assess their understanding of EMF, taking into account the pragmatic context of their practice and of their constraints.

Salomon, Danielle

2010-11-01

93

Electric shock and elevated EMF levels due to triplen harmonics  

SciTech Connect

The increasing use of single phase rectifiers for electric power conversion in residential applications increases harmonic load on utility systems. Many papers have analyzed the effect of these loads on power quality and equipment loadability. However, there are two more critical concerns for harmonic loads served phase to neutral on multi-grounded wye systems. Triplen harmonics, particularly the third, add in the neutral and have little diversity between loads. The higher neutral currents may cause significant problems. Neutral to earth voltages will increase near the substations which could increase stray voltage complaints. The additional neutral current on three phase lines will elevate EMF levels especially in the fringe areas. This paper provides fundamental understanding of triplen harmonic influence on stray voltage and EMF related to multi-grounded wye electric distribution systems.

Tran, T.Q.; Conrad, L.E.; Stallman, B.K. [PSI Energy, Inc., Plainfield, IN (United States)] [PSI Energy, Inc., Plainfield, IN (United States)

1996-04-01

94

Three-phase power factor controller with induced EMF sensing  

NASA Technical Reports Server (NTRS)

A power factor controller for an ac induction motor is provided which is of the type comprising thyristor switches connected in series with the motor, phase detectors for sensing the motor current and voltage and providing an output proportional to the phase difference between the motor voltage and current, and a control circuit, responsive to the output of the phase detector and to a power factor command signal, for controlling switching of the thyristor. The invention involves sensing the induced emf produced by the motor during the time interval when the thyristor is off and for producing a corresponding feedback signal for controlling switching of the thyristor. The sensed emf is also used to enhance soft starting of the motor.

Nola, F. J. (inventor)

1984-01-01

95

Effects of Polygonum aviculare herbal extract on sperm parameters after EMF exposure in mouse.  

PubMed

Electromagnetic fields with high energy same as ionizing radiation inserts their destructive effects via free radical production. Using antioxidants or herbal plants with antioxidants components could diminish hazardous effects of EMF. Polygonum aviculare has a high amount of phenolic and flavonoid and proved that has antioxidants effects. The aim of this study was to evaluate the effects of Polygonum aviculare herbal extract on sperm parameters after EMF exposure in mouse. Twenty four male mice, 8 weeks divided to 4 groups (one control and three experimental groups). Control group didn't receive EMF exposure. EMF group mice received 3 mT EMF during 2 months, 4 h daily and 5 days weekly. Polygonum aviculare group received 50 mg kg(-1) herbal extract during 2 months and poly -EMF group received 3 mT EMF during 2 months, 4 h daily and 5 days weekly and 50 mg kg(-1) herbal extract during 2 months. After 2 months the mice sacrificed with cervical dislocation and sperm obtained from tail of epididymis and motility and morphology of them were analyzed. Sperm analysis results showed that in group with Polygonum aviculare, morphology and motility of sperm developed (p < 0.05). Present results showed that EMF can reduce motility of sperm and treatment of Polygonum aviculare after EMF exposure developed sperm quality after EMF exposure. PMID:22308654

Milan, P B; Nejad, D M; Ghanbari, A A; Rad, J S; Nasrabadi, H T; Roudkenar, M H; Roushandeh, A M; Goldust, M

2011-07-01

96

Emf study of ionic composition of tungstate melts  

Microsoft Academic Search

The emf of cells W (1-x)NaâWOâ + xWOâ Pt, Oâ were measured for x-values between 0.01 and 0.20 over the temperature range from 1023 to 1223°K. It was shown that the experimental results can be described satisfactorily by a model for ionic composition of the melts which assumes that ions WOâ\\/sup 2 -\\/, WâOâ\\/sup 2 -\\/, O\\/sup 2 -\\/, and

A. Yu. Khvatov; A. N. Baraboshkin; K. P. Tarasova

1986-01-01

97

Facilities for calibration of dc emf measures and voltmeters  

SciTech Connect

A set of instruments for reproduction and storage of the emf and dc voltage unit and for transferring it directly to the location where measuring instruments (MIs) are used with an accuracy of (3-5) {center_dot} 10{sup {minus}7}, developed at the {open_quotes}VNIIFTRI{close_quotes} Research and Production Association (RPA) is described. The metrological characteristics of the set are investigated.

Gumenyuk, V.S.; Karpov, O.V.; Kutovoi, V.D.; Sarandi, A.E.; Shakirzyanova, F.R.; Shulga, V.M.

1994-06-01

98

Low-level EMFs are transduced like other stimuli  

Microsoft Academic Search

The aims of this study were to test the theory that transduction of low-level electromagnetic fields (EMFs) is mediated like other stimuli, and to determine the false-negative rate of the method used to assess the occurrence of transduction (intra-subject comparison of stimulus and non-stimulus states (ICOS)). A light stimulus was chosen as a basis of comparison because light could be

Andrew A. Marino; Glenn B. Bell; Andrew Chesson

1996-01-01

99

Emf, maximum power and efficiency of fuel cells  

SciTech Connect

The ideal voltage of steady-flow fuel cells is usually expressed by Emf = [minus] [Delta]G[degree]/nF where [Delta]G[degree] is the Gibbs free energy of reaction'' for the oxidation of the fuel at the supposed temperature of operation of the cell. Furthermore, the ideal power of the cell is expressed as the product of the fuel flow rate with this emf. Such viewpoints are flawed in several respects. Even if the cell operates isothermally, the use of the conventional [Delta]G[degree] of reaction (a) assumes that the products of reaction leave separately from one another ( and from any unused fuel); and (b) when [Delta]S of reaction is positive, it assumes that a free heat source exists at the operating temperature, whereas if [Delta]S is negative, it neglects the potential power which theoretically could be obtained from the heat released during oxidation. Moreover, (c) the usual cell does not operate isothermally, but (virtually) adiabatically. Comment (a) is often accounted for by employing the Nernst equation to correct for the dilution of reactants and/or products. Nevertheless, comments (b) and (c) remain pertinent. Rather than with emf, the proper starting place is with power output. The ideal power is that which would be obtained if the fuel were oxidized without irreversible entropy generation. Among other factors, this ideal power output depends upon the ratio of oxidant to fuel flow rate (e.g., air-fuel ratio) and the percentage of fuel oxidation. The ideal voltage is deduced from the ideal power. Therefore, (d) ideal power is not equal to the product of emf with current (unless the amount of fuel utilized is infinitesimal). Examples are presented which illustrate such affects and their importance for the evaluation of ideal power and of efficiency.

Gaggioli, R.A.; Dunbar, W.R. (Marquette Univ., Milwaukee, WI (United States))

1993-06-01

100

Emf study of ionic composition of tungstate melts  

SciTech Connect

The emf of cells W (1-x)Na/sub 2/WO/sub 4/ + xWO/sub 3/ Pt, O/sub 2/ were measured for x-values between 0.01 and 0.20 over the temperature range from 1023 to 1223/sup 0/K. It was shown that the experimental results can be described satisfactorily by a model for ionic composition of the melts which assumes that ions WO/sub 4//sup 2 -/, W/sub 2/O/sub 7//sup 2 -/, O/sup 2 -/, and Na/sub +/ with concentration-independent activity coefficients exist in the melt. It was found that the emf of cells Pt, O/sub 2/ 0.9 Na/sub 2/WO/sub 4/ + 0.1 WO/sub 3/ (1-x)Na/sub 2/WO/sub 4/ + xWO/sub 3/ O/sub 2/,Pt calculated via this model do not differ by more than 8 mV from the experimental emf over the concentration range from 0.5 to 20 mole % of WO/sub 3/.

Khvatov, A. Yu.; Baraboshkin, A.N.; Tarasova, K.P.

1986-06-01

101

Absolute nuclear material assay  

DOEpatents

A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

2012-05-15

102

Absolute nuclear material assay  

DOEpatents

A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

Prasad, Manoj K. (Pleasanton, CA) [Pleasanton, CA; Snyderman, Neal J. (Berkeley, CA) [Berkeley, CA; Rowland, Mark S. (Alamo, CA) [Alamo, CA

2010-07-13

103

The process of consensus on EMF: SAB review of the EPA draft document on EMF and cancer  

SciTech Connect

The EPA Draft Document on EMF and Cancers grew out of an earlier effort by EPA to track biological effects literature relative to radio-frequency (RF) exposure. Scope of the document was broadened to include extremely low frequency electric and magnetic fields prior to an announcement in 1986 that EPA would formally review the whole area of non-ionizing radiation. An extensive survey of the relevant bioeffects and epidemiologic literature was carried out, and writing on the document began in earnest on the document sometime in 1989. In its draft form, the document reviewed the literature on mechanisms of Interaction between electromagnetic fields and biological tissue, EMF epidemiologic studies, supporting evidence for carcinogenicity and research needs. In the early summer of 1990, a draft of the document was reviewed by some 22 individuals within the EPA and other government agencies. It was also sent out for external review to an additional 9 qualified scientists who had worked in the area and were familiar with EMF-related literature in epidemiology, biology, and physics. Many of the comments sent to EPA from this first review, prior to release of the draft for public comment, were strikingly similar to those resulting from the second (public) review process. Thus, it appears that much of the controversy that was later associated with the document could have been avoided had the authors been diligent in following the recommendations of the initial set of reviewers.

Wilson, B.W.

1992-06-01

104

Contributing to a precise and accurate chronostratigraphic time scale for climatic records: Absolute dating and paleomagnetism in lavas  

NASA Astrophysics Data System (ADS)

Understanding climatic mechanisms requires a robust and precise timescale allowing long-distance and multi-archives correlations. A unique tool to construct such time scales is provided by the Earth magnetic field (EMF), which is independent from climatic variations and the past evolution of which is recorded in most of the geological/climatic archives. Sedimentary sequences provide continuous records of relative intensities of the EMF on stratigraphic time scales, usually based on orbital tuning. They are transferred onto absolute intensity scale and chronological time scale using robust tie points available for the past ~40 ka. However, for older periods this calibration remains poorly constrained. Our study reports on new tie points over the last 200 ka by combining paleomagnetic and geochronological (K/Ar and 40Ar-39Ar dating) studies on lavas. Based on the K-Ar LSCE age database, a set of 18 lava flows corresponding to potential geomagnetic excursions and/or highs and lows in the paleomagnetic intensity as observed from sediments and occurring in the studied time-window were selected in the Canary Islands (Tenerife, La Palma and Gran Canaria). A total of 205 oriented cores were taken from these 18 lava flows. Rock magnetic experiments include thermomagnetic analyses on each core, hysteresis loop and First Order Reversal Curves. Stepwise thermal demagnetizations in zero-field provided reliable mean-site paleomagnetic direction of the EMF for 15 of the flows. Paleointensity values were determined using the original Thellier and Thellier method. Based on previous experiments, 170 samples were analyzed, among which 51% provided reliable paleointensity values (determined using PICRIT-03 criteria). The geochronological study focused on 40Ar-39Ar dating. Based on preliminary paleomagnetic results, 13 flows were analyzed and 11 provided ages consistent at the 2 sigma level with the already available K-Ar ages. This coupled K/Ar - 40Ar-39Ar results strongly constrain the chronological framework. The new obtained paleomagnetic/age data will be compared to both sedimentary and volcanic data base.

Sasco, Romain; Guillou, Herve; Kissel, Catherine; Wandres, Camille; Carracedo, Juan-Carlos; Perez Torrado, Francisco Jose

2014-05-01

105

EMF1 and PRC2 Cooperate to Repress Key Regulators of Arabidopsis Development  

PubMed Central

EMBRYONIC FLOWER1 (EMF1) is a plant-specific gene crucial to Arabidopsis vegetative development. Loss of function mutants in the EMF1 gene mimic the phenotype caused by mutations in Polycomb Group protein (PcG) genes, which encode epigenetic repressors that regulate many aspects of eukaryotic development. In Arabidopsis, Polycomb Repressor Complex 2 (PRC2), made of PcG proteins, catalyzes trimethylation of lysine 27 on histone H3 (H3K27me3) and PRC1-like proteins catalyze H2AK119 ubiquitination. Despite functional similarity to PcG proteins, EMF1 lacks sequence homology with known PcG proteins; thus, its role in the PcG mechanism is unclear. To study the EMF1 functions and its mechanism of action, we performed genome-wide mapping of EMF1 binding and H3K27me3 modification sites in Arabidopsis seedlings. The EMF1 binding pattern is similar to that of H3K27me3 modification on the chromosomal and genic level. ChIPOTLe peak finding and clustering analyses both show that the highly trimethylated genes also have high enrichment levels of EMF1 binding, termed EMF1_K27 genes. EMF1 interacts with regulatory genes, which are silenced to allow vegetative growth, and with genes specifying cell fates during growth and differentiation. H3K27me3 marks not only these genes but also some genes that are involved in endosperm development and maternal effects. Transcriptome analysis, coupled with the H3K27me3 pattern, of EMF1_K27 genes in emf1 and PRC2 mutants showed that EMF1 represses gene activities via diverse mechanisms and plays a novel role in the PcG mechanism.

Kim, Sang Yeol; Lee, Jungeun; Eshed-Williams, Leor; Zilberman, Daniel; Sung, Z. Renee

2012-01-01

106

Sensorless control strategy for salient-pole PMSM based on extended EMF in rotating reference frame  

Microsoft Academic Search

This paper presents a novel sensorless control strategy for a salient-pole permanent magnet synchronous motor. A new model of salient-pole PMSM using an extended electromotive force (EMF) in the rotating reference frame is utilized to estimate both position and speed. The extended EMF is estimated by a least-order observer, and the estimation position error are obtained from the extended EMF.

Shigeo Morimoto; Keisuke Kawamoto; Masayuki Sanada; Yoji Takeda

2001-01-01

107

Extended EMF and parameter observer for sensorless controlled PMSM-machines at low speed  

Microsoft Academic Search

The paper describes an extended EMF- and parameter observer for sensorless controlled PMSM-machines. Therefore a combination of INFORM-method and EMF-model is used. At low speed, the reference position of the permanent magnet flux is calculated by INFORM-method and compared with the permanent magnet flux provided by EMF-model. By transformation of the voltage equation into a current-oriented reference frame, a 4th

Manfred Schrödl; Matthias Hofer; Wolfgang Staffler

2007-01-01

108

Rate of rotation measurement using back-EMFS associated with windings of a brushless DC motor  

NASA Technical Reports Server (NTRS)

A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is integrated and multiplied by the back-emf associated with an adjacent winding. The multiplied outputs associated with each winding are combined to produce a directionally sensitive DC output proportional only to the rate of rotation of the motor's shaft.

Howard, David E. (Inventor)

2000-01-01

109

Intelligent communication: The future of EMF discourse and risk governance?  

NASA Astrophysics Data System (ADS)

It is proposed that to help facilitate progress in electromagnetic field (EMF) risk governance and actively address potential concerns whilst encouraging environmentally-sound technical advancement, the ground rules of stakeholder participation / debate may benefit from being radically overhauled to encourage more openness, trust, understanding, transparency and innovation. It is further proposed that two-way communication should be actively promoted, as should proactive thinking and informed discussions of risk (which address realistically the concerns of all parties). The creation/development/adoption of enhanced best practice solutions and precautionary principle measures should also be encouraged.

Jamieson, Isaac A.

2010-04-01

110

EMF Science Review Symposium Breakout Group Reports for Epidemiological Research Findings. Held in San Antonio, Texas on January 12-14, 1998. EMF RAPID: Electric and Magnetic Fields Research and Public Information Dissemination Program.  

National Technical Information Service (NTIS)

Table of Contents: Epidemiological Research Findings; EMF Science Review Sumposium Participants; EMF and Childhood Cancer; Exposure Assessment and Epidemiological Studies: How Well Have the Risk Factors Been Identified; Methodological Issues and Problems:...

1998-01-01

111

Safety of High Speed Guided Ground Transportation Systems. Broadband Magnetic Fields: Their Possible Role in EMF-Associated Bioeffects.  

National Technical Information Service (NTIS)

The report reviews electric and magnetic field (EMF) exposures from electrical transportation systems, including electrically powered rail and magnetic levitation (maglev). Material also covered includes research concerning biological effects of EMF expos...

A. Pilla B. Wilson D. Goellner N. Hankin R. Reiter

1993-01-01

112

Absolute hardness: companion parameter to absolute electronegativity  

SciTech Connect

For neutral and charged species, atomic and molecular, a property called absolute hardness eta is defined. Let E(N) be a ground-state electronic energy as a function of the number of electrons N. As is well-known, the derivative of E(N) with respect to N, keeping nuclear charges Z fixed, is the chemical potential ..mu.. or the negative of the absolute electronegativity chi: ..mu.. = (deltaE/deltaN)/sub Z/ = /sup -/chi. The corresponding second derivative is hardness: 2eta = (delta..mu../deltaN)/sub Z/ = (deltachi/deltaN)/sub Z/ = (delta/sup 2/E/deltaN/sup 2/)/sub Z/. Operational definitions of chi and eta are provided by the finite difference formulas (the first due to Mulliken) chi = 1/2(I+A), eta = 1/2(I-A), where I and A are the ionization potential and electron affinity of the species in question. Softness is the opposite of hardness: a low value of eta means high softness. The principle of hard and soft acids and bases is derived theoretically by making use of the hypothesis that extra stability attends bonding of A to B when the ionization potentials of A and B in the molecule (after charge transfer) are the same. For bases B, hardness is identified as the hardness of the species B/sup +/. Tables of absolute hardness are given for a number of free atoms, Lewis acids, and Lewis bases, and the values are found to agree well with chemical facts. 1 figure, 3 tables.

Parr, R.G.; Pearson, R.G.

1983-12-28

113

Reduction of electromagnetic field (EMF) of wireless power transfer system using quadruple coil for laptop applications  

Microsoft Academic Search

In this paper, we proposed an effective coil design for electromagnetic field (EMF) noise reduction from the wireless power transfer system by using quadruple coils in transmitter and receiver for laptop computer application. By using quadruple coils for transmitter and receiver, EMF noise was significantly reduced with negligible change in induced voltage. 3D simulations and the field distributions are shown

Seungyoung Ahn; Hyun Ho Park; Cheol-Seung Choi; Jonghoon Kim; Eakhwan Song; Hark Byung Park; Hongseok Kim; Joungho Kim

2012-01-01

114

Rubber and alumina gaskets retain vacuum seal in high temperature EMF cell  

NASA Technical Reports Server (NTRS)

Silicone rubber gasket and an alumina gasket retain a vacuum inside a high temperature EMF cell in which higher and lower density liquid metal electrodes are separated by an intermediate density fused salt electrolyte. This innovation is in use on a sodium bismuth regenerable EMF cell in which the fused salts and metals are at about 500 deg to 600 deg C.

Hesson, J. C.

1966-01-01

115

Use of C. Elegans as a model organism for sensing the effects of ELF-EMFs  

NASA Astrophysics Data System (ADS)

For the past two decades, there have been concerns and controversy about the effects on human health of the increased exposure to extremely-low-frequency (ELF) electromagnetic fields (EMFs) resulting from electrification, in both residential and industrial settings. Several epidemiological studies have implicated ELF-EMFs averaging 0.4 ?mUTesla (T) or more in increased risk of cancer, especially childhood leukaemia [1,2]; there have also been many reports demonstrating effects of power-frequency EMFs on cells [outlined in 1,3]. Unfortunately, however, the precise mechanisms by which ELF-EMFs exert biological effects have proven difficult to define and results of various studies have often been hard to reproduce [1]. We believe that C. elegans offers an exciting opportunity to elucidate the effects of power-frequency EMFs on cell signalling pathways within the whole organism and are therefore investigating the effects of ELF-EMF exposure on MAPK signalling in intact worms and fertilized embryos. Through taking a targeted approach to studying the effects of ELF-EMF's on MAPK signalling in C. elegans we aim to gather data that is physiologically relevant. Presently, this research is at a preliminary stage of preparation, and more detailed results on the exposure of Caenorhabditis elegans to ELF-EMF radiation will be presented at the conference itself.

Lacchini, A. H.; Everington, M. L.; Augousti, A. T.; Walker, A. J.

2007-07-01

116

Safety of High Speed Guided Ground Transportation Systems: EMF Exposure Environments. Summary Report.  

National Technical Information Service (NTIS)

The paper presents an overview of American exposure assessments for electric and magnetic fields (EMF) in the frequency range from 0 to 3 kHz. The exposure information available is very limited for all but a few occupations and sources of EMF. Much of the...

D. Goellner T. Inge L. Gillette N. Hankin B. Hostage

1993-01-01

117

Effect of short-range order on thermo-emf of binary alloys  

Microsoft Academic Search

The thermo-emf of binary disordered alloys is calculated, taking into account correlations in the distribution of atoms of different kinds over the lattice. It is shown that the presence of short-range order in the alloys may lead to a nonlinear temperature dependence of the thermo-emf and cause a change in its sign.

S. I. Masharov; N. M. Rybalko

1976-01-01

118

EVALUATION OF EXPOSURE TO EMFs IN DIFFERENT LAYOUTS OF TRANSFORMER ROOMS  

Microsoft Academic Search

Indoor Distribution Transformer Rooms (IDTRs) contain the following sources of EMFs: busbars, isolating switches, cables, fuses, distribution transformer and capacitor bank. These sources can be significant contributors to the magnetic field in areas both inside and outside the location fence. In the IDTRs environment, the electrical workers are exposed to the EMFs during about one working hours. For this study,

Mohamed ASHOUR; Kamelia YOUSSEF; Hanaa KARAWIA

119

A novel direct back EMF detection for sensorless brushless DC (BLDC) motor drives  

Microsoft Academic Search

A novel back EMF detection method for sensorless BLDC motor drives without the motor neutral point voltage information is presented in this paper. The true phase back EMF signal can be directly obtained from the motor terminal voltage by properly choosing the PWM and sensing strategy. As a result, the method proposed is not sensitive to switching noise, no filtering

Jianwen Shao; Dennis Nolan; Thomas Hopkins

2002-01-01

120

Electromagnetic fields (EMF): Do they play a role in children's environmental health (CEH)?  

Microsoft Academic Search

Possible adverse health effects of exposure to electric, magnetic and electromagnetic fields (EMF), and especially the question of whether there exists a special vulnerability of children, have been a much discussed topic during the last two decades. Static fields produce health effects only in very rare and exceptional circumstances at extremely high field intensities. As for low-frequency EMF, the results

Matthias Otto; Karl Ernst von Mühlendahl

2007-01-01

121

International climate policy architectures: Overview of the EMF 22 International Scenarios  

Microsoft Academic Search

This paper presents an overview of the study design for, and the results of, the EMF 22 International Scenarios. The EMF 22 International Scenarios engaged ten of the world's leading integrated assessment (IA) models to focus on the combined implications of three factors integral to international climate negotiations: (1) the long-term climate-related target, expressed in this study in terms of

Leon Clarke; Jae Edmonds; Volker Krey; Richard Richels; Steven Rose; Massimo Tavoni

2009-01-01

122

The EMF dilemma: Decision-making amid scientific uncertainty  

SciTech Connect

In 1989, residents of Monticito, CA about 90 mi NW of Los Angeles called to the attention of local school and county health officials a leukemia cluster observed in children in the area. In this cluster, the rate of cancer in children appeared to be five times the expected rate. Montecito Union School is bisected by 66-kV power lines, as they come out into the community from a substation directly adjacent to the school. The lines pass within 15 feet of the north side of Howard School. After the State Department of Health identified this as a legitimate cancer cluster, the state responded by taking EMF readings in September 1989 on and near Montecito Union School and produced a report in December of that year. In the weeks following the December 1989 report, concern built in the community over perceived weaknesses in the state's methodology. Doubt was cast over the state's willingness to perform a thorough investigation. The cognizant utility, Southern California Edison, was involved early in the information sharing. The author discusses the mediated negotiation, and recommends that utility planners be candid, provide honest answers, work openly and aggressively with communities, and make EMF information easily accessible.

Sage, C. (Sage Associates, Montecito, CA (USA))

1991-04-01

123

Discussion of an EMF (electric and magnetic field) protocol  

SciTech Connect

In 1989, three collaborating cancer research agencies initiated large-scale case-control studies of the postulated association between residential exposure to 50/60-Hz electric and magnetic fields and the induction of childhood leukemia. To facilitate design of the exposure assessment component of these studies, the Electric Power Research Institute sponsored a two-day workshop on February 6--8, 1989. The workshop's objective was to develop a detailed state-of-the science'' protocol for direct and/or surrogate measurements of a subject's EMF exposure history. Emphasis was placed on the difficulties inherent in measuring the exposure of small children. Attendees were divided into three working groups, addressing the following questions, respectively: How can historical exposure best be assessed; what should be measured outdoors; and what should be measured indoors Consensus on a single protocol was not found to be possible, given the state of knowledge about EMF exposure and the pathophysiology of childhood leukemia. However, the discussion produced a comprehensive analysis of the issues involved in addressing the crucial questions of who and what should be measured, and when, where and how these measurements should take place. In particular, discussion focused on: personal monitoring versus area measurements; exposure metrics; relevant time periods over the subjects life for measurement; location and duration of measurements; and protocol development considerations. Attendees expressed strong interest in another, similar workshop sometime in the future. 1 tab.

Afifi, A.A.; Banks, R.S.; Kheifets, L.I.; Newman, B. (Banks (Robert S.) Associates, Inc., Minneapolis, MN (USA))

1990-07-01

124

Absolute biological needs.  

PubMed

Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses. PMID:23586876

McLeod, Stephen

2014-07-01

125

The effect of applied electric currents on inherent cellular E.M.F. and its possible significance in cell correlation  

Microsoft Academic Search

Summary 1.The inherent E.M.F. of the onion root is altered by an applied electric current in fundamentally the same manner as a storage battery.2.If the voltage of the current source is opposed to the voltage of the root the inherent E.M.F. is increased; if they are in series the inherent E.M.F. is decreased.3.The magnitude of change of inherent E.M.F. varies

Gordon Marsh

1930-01-01

126

Absolute configuration of franganine.  

PubMed

The absolute configuration of franganine (1), a cyclopeptide alkaloid isolated from the methanol root bark extract of Discaria americana, was established on the basis of detailed NMR spectroscopic data and X-ray diffraction analysis of its salt (2). PMID:22680778

Caro, Miguel S B; de Oliveira, Leonardo H; Ilha, Vinicius; Burrow, Robert A; Dalcol, Ionara I; Morel, Ademir F

2012-06-22

127

Verifying Chandra Absolute Times  

Microsoft Academic Search

Calibrating the absolute time accuracy of Chandra requires requires the efforts of many people. Here we present some attempts to verify this accuracy. HRC observations of the Crab indicated that the Chandra clock is within 0.2 msec of being correct. Checking ACIS requires correcting for the time delays caused by the continuous clocking readout. A method is presented to correct

Allyn Tennant

2001-01-01

128

Absolute Low Speed Anemometer  

Microsoft Academic Search

An absolute anemometer suitable for measurements in gases under a wide variety of conditions is described. The instrument, based on an idea first used by Kovasznay, utilizes the temperature fluctuations in the wake of a sinusoidally heated fine wire as tracer. A second hot-wire detects the fluctuations, and the phase change between two successive positions of this wire can be

R. E. Walker; A. A. Westenberg

1956-01-01

129

Absolute ultraviolet stellar fluxes  

NASA Technical Reports Server (NTRS)

A study, made to calibrate the ultraviolet spectra of stars to within an absolute accuracy of 10%, is summarized. Data were taken by a 13 inch UVR telescope onboard several rocket flights. Calibrated and existing ground based data are in reasonable agreement. Calibrated results are presented in graphical form.

Evans, D. C.

1972-01-01

130

Precise determination of the absolute isotopic abundance ratio and the atomic weight of chlorine in three international reference materials by the positive thermal ionization mass spectrometer-Cs2Cl+-graphite method.  

PubMed

Because the variation in chlorine isotopic abundances of naturally occurring chlorine bearing substances is significant, the IUPAC Inorganic Chemistry Division, Commission on Isotopic Abundances and Atomic Weights (CIAAW-IUPAC) decided that the uncertainty of atomic weight of chlorine (A(r)(Cl)) should be increased so that the implied range was related to terrestrial variability in 1999 (Coplen, T. B. Atomic weights of the elements 1999 (IUPAC Technical Report), Pure Appl. Chem.2001, 73(4), 667-683; and then, it emphasized that the standard atomic weights of ten elements including chlorine were not constants of nature but depend upon the physical, chemical, and nuclear history of the materials in 2009 (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396). According to the agreement by CIAAW that an atomic weight could be defined for one specified sample of terrestrial origin (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396), the absolute isotope ratios and atomic weight of chlorine in standard reference materials (NIST 975, NIST 975a, ISL 354) were accurately determined using the high-precision positive thermal ionization mass spectrometer (PTIMS)-Cs(2)Cl(+)-graphite method. After eliminating the weighing error caused from evaporation by designing a special weighing container and accurately determining the chlorine contents in two highly enriched Na(37)Cl and Na(35)Cl salts by the current constant coulometric titration, one series of gravimetric synthetic mixtures prepared from two highly enriched Na(37)Cl and Na(35)Cl salts was used to calibrate two thermal ionization mass spectrometers in two individual laboratories. The correction factors (i.e., K(37/35) = R(37/35meas)/R(37/35calc)) were obtained from five cycles of iterative calculations on the basis of calculated and determined R((37)Cl/(35)Cl) values in gravimetric synthetic mixtures. The absolute R((37)Cl/(35)Cl) ratios for NIST SRM 975, NIST 975a, and ISL 354 by the precise calibrated isotopic composition measurements are 0.319876 ± 0.000067, 0.319768 ± 0.000187, and 0.319549 ± 0.000044, respectively. As a result, the atomic weights of chlorine in NIST 975, NIST 975a, and ISL 354 are derived as 35.45284(8), 35.45272(21), and 35.45252(2) individually, which are consistent with the issued values of 35.453(2) by IUPAC in 1999. PMID:23088631

Wei, Hai-Zhen; Jiang, Shao-Yong; Xiao, Ying-Kai; Wang, Jun; Lu, Hai; Wu, Bin; Wu, He-Pin; Li, Qing; Luo, Chong-Guang

2012-12-01

131

Absolute beam brightness detector  

SciTech Connect

In generally accepted emittance measurement, main attention is concentrated on emittance areas {epsilon}{sub x}, {epsilon}{sub y} occupied by desired part of ion beam in transverse phase space and shape of these areas. The absolute beam phase density (brightness) as usually is not measured directly and the average beam brightness B is calculated from a beam intensity I and the transverse emittances. In the ion source and low energy beam transport (LEBT) optimization, it is important to preserve the beam brightness because some aberration of ion optic and beam instabilities can decrease the brightness of the central part of ion beam significantly. For these brightness measurements, it is convenient to use an absolute beam brightness detector with the brightness determination from one short considered in this article.

Dudnikov, Vadim [Muons, Inc., Batavia, Illinois 60510 (United States)

2012-02-15

132

EMF and transmission line siting: The emerging state regulatory framework and implications for utilities  

SciTech Connect

One of the thorniest policy issues facing electric utilities and regulators in the potential public health risk of electromagnetic fields (EMF). EMF has been the focus of numerous biological, epidemiological, and toxicological studies, the results of which have been inconclusive and sometimes contraditory. Collectively the studies seem to indicate that EMF has demonstrable biological effects, but the extent to which these effects adversely impact human health remains unclear. This article summarizes the response of the 19 states which have, either through their public utility commissions, special task forces, legislatures, or other agencies, addressed the EMF issue. Responses covered include the following: prudent avoidance; construction moratoria; field strength standards; maintaining status quo; and the response of the utilities.

Gulliver, J.W. [Pierce, Atwood, Scribner, Allen, Smith & Lancaster, Portland, ME (United States); Vito, C.C.

1993-12-31

133

Modelling indoor electromagnetic fields (EMF) from mobile phone base stations for epidemiological studies.  

PubMed

Radio frequency electromagnetic fields (RF-EMF) from mobile phone base stations can be reliably modelled for outdoor locations, using 3D radio wave propagation models that consider antenna characteristics and building geometry. For exposure assessment in epidemiological studies, however, it is especially important to determine indoor exposure levels as people spend most of their time indoors. We assessed the accuracy of indoor RF-EMF model predictions, and whether information on building characteristics could increase model accuracy. We performed 15-minute spot measurements in 263 rooms in 101 primary schools and 30 private homes in Amsterdam, the Netherlands. At each measurement location, we collected information on building characteristics that can affect indoor exposure to RF-EMF, namely glazing and wall and window frame materials. Next, we modelled RF-EMF at the measurement locations with the 3D radio wave propagation model NISMap. We compared model predictions with measured values to evaluate model performance, and explored if building characteristics modified the association between modelled and measured RF-EMF using a mixed effect model. We found a Spearman correlation of 0.73 between modelled and measured total downlink RF-EMF from base stations. The average modelled and measured RF-EMF were 0.053 and 0.041mW/m(2), respectively, and the precision (standard deviation of the differences between predicted and measured values) was 0.184mW/m(2). Incorporating information on building characteristics did not improve model predictions. Although there is exposure misclassification, we conclude that it is feasible to reliably rank indoor RF-EMF from mobile phone base stations for epidemiological studies. PMID:24632329

Beekhuizen, J; Vermeulen, R; van Eijsden, M; van Strien, R; Bürgi, A; Loomans, E; Guxens, M; Kromhout, H; Huss, A

2014-06-01

134

Subcutaneous Arteriolar Vasomotion Changes During and After ELF-EMF Exposure in Mice in Vivo  

Microsoft Academic Search

Summary  Biological effects of extremely low-frequency electromagnetic fields (ELF-EMF) on microcirculation were investigated in vivo by monitoring arteriole diameters in conscious mice. Measurements of blood vessel diameter were monitored 33 min non-stop\\u000a before during and after exposure with ELF-EMF and every 389 ms blood vessel diameter were calculated.\\u000a \\u000a Using a dorsal skinfold chamber (DSC), and following caudal vein injection of FITC-dextran

L. Traikov; A. Ushiyama; G. Lawlor; R. Sasaki; C. Ohkubo

2005-01-01

135

EMF signals and ion\\/ligand binding kinetics: prediction of bioeffective waveform parameters  

Microsoft Academic Search

The kinetics of an electromagnetic field (EMF) target pathway are used to estimate frequency windows for EMF bioeffects. Ion\\/ligand binding is characterized via first order kinetics from which a specific electrical impedance can be derived. The resistance\\/capacitance properties of the binding pathway impedance, determined by the kinetics of the rate-determining step, define the frequency range over which the target pathway

A. A Pilla; D. J Muehsam; M. S Markov; B. F Sisken

1999-01-01

136

Lack of an EMF-induced genotoxic effect in the ames assay  

Microsoft Academic Search

A few epidemiological studies have linked exposure to electromagnetic fields (EMF) and the incidence of cancer. Since many carcinogens are mutagens in the Ames assay, the purpose of this study was to determine if exposure of four tester strains of Salmonella typhimurium (TA97a, TA98, TA100, and TA102) to EMF would increase their rate of mutation. Parallel plate electrodes and Helmholtz

Melissa A. Morandi; Cindy M. Pak; Robert P. Garen; Linda D. Caren

1996-01-01

137

Sensorless control strategy for salient-pole PMSM based on extended EMF in rotating reference frame  

Microsoft Academic Search

This paper presents a novel sensorless control strategy for a salient-pole permanent-magnet synchronous motor (PMSM). A new model of a salient-pole PMSM using an extended electromotive force (EMF) in the rotating reference frame is utilized to estimate both position and speed. The extended EMF is estimated by a least-order observer, and the estimation position error is obtained from the extended

Shigeo Morimoto; Keisuke Kawamoto; Masayuki Sanada; Yoji Takeda

2002-01-01

138

Low frequency EMF regulates chondrocyte differentiation and expression of matrix proteins  

Microsoft Academic Search

This study describes the enhancement of chondrogenic differentiation in endochondral ossification by extremely low frequency pulsed electric\\/magnetic fields (EMFs). The demineralized bone matrix (DBM)-induced endochondral ossification model was used to examine the effects of EMF stimulation. [35S]-Sulfate and [3H]-thymidine incorporation and glycosaminoglycan (GAG) content were determined by standard methods. Proteoglycan (PG) and GAG molecular size and composition were determined by

Deborah Mc K. Ciombor; Gayle Lester; Roy K. Aaron; Peter Neame; Bruce Caterson

2002-01-01

139

Genetic Regulation of Shoot Development in Arabidopsis: Role of the EMF Genes  

Microsoft Academic Search

To investigate the genetic mechanism regulating Arabidopsis shoot maturation and development, we characterized eight emf mutants that bypassed the vegetative phase of the life cycle. Genetic complementation studies identified two EMF loci; both mapped to chromosome five. Double mutant analysis showed that the early- and late-flowering mutants, co, fb, elf1, elf2, and elf3, could not rescue vegetative development in the

Chang-Hsien Yang; Ling-Jing Chen; Z. Renee Sung

1995-01-01

140

Electromagnetic field (EMF) effects on channel activity of nanopore OmpF protein  

Microsoft Academic Search

In this study, the effects of nonionizing electromagnetic fields (EMF; 925 MHz) on the OmpF porin channel have been characterized\\u000a at the single-channel level. Channel activity was recorded in real time by the voltage clamp method. Our results showed an\\u000a increase in the frequency of channel gating and voltage sensitivity. The effects of EMF lasted for several milliseconds after\\u000a the field

M. Mohammadzadeh; H. Mobasheri; F. Arazm

2009-01-01

141

EMF 7 model comparisons: key relationships and parameters  

SciTech Connect

A simplified textbook model of aggregate demand and supply interprets the similarities and differences in the price and income responses of the various EMF 7 models to oil and policy shocks. The simplified model is a marriage of Hicks' classic IS-LM formulation of the Keynesian theory of effective demand with a rudimentary model of aggregate supply, combining a structural Phillips curve for wage determination and a markup theory of price determination. The reduced-form income equation from the fix-price IS-LM model is used to define an aggregate demand (AD) locus in P-Y space, showing alternative pairs of the implicit GNP deflator and real GNP which would simultaneously satisfy the saving-investment identity and the condition for money market equilibrium. An aggregate supply (AS) schedule is derived by a similar reduction of relations between output and labor demand, unemployment and wage inflation, and the wage-price-productivity nexus governing markup pricing. Given a particular econometric model it is possible to derive IS and LM curves algebraically. The resulting locuses would show alternative combinations of interest rate and real income which equilibrate real income identity on the IS side and the demand and supply of money on the LM side. By further substitution the reduced form fix-price income relation could be obtained for direct quantification of the AD locus. The AS schedule is obtainable by algebraic reduction of the structural supply side equations.

Hickman, B.G.

1983-12-01

142

Electronic Absolute Cartesian Autocollimator  

NASA Technical Reports Server (NTRS)

An electronic absolute Cartesian autocollimator performs the same basic optical function as does a conventional all-optical or a conventional electronic autocollimator but differs in the nature of its optical target and the manner in which the position of the image of the target is measured. The term absolute in the name of this apparatus reflects the nature of the position measurement, which, unlike in a conventional electronic autocollimator, is based absolutely on the position of the image rather than on an assumed proportionality between the position and the levels of processed analog electronic signals. The term Cartesian in the name of this apparatus reflects the nature of its optical target. Figure 1 depicts the electronic functional blocks of an electronic absolute Cartesian autocollimator along with its basic optical layout, which is the same as that of a conventional autocollimator. Referring first to the optical layout and functions only, this or any autocollimator is used to measure the compound angular deviation of a flat datum mirror with respect to the optical axis of the autocollimator itself. The optical components include an illuminated target, a beam splitter, an objective or collimating lens, and a viewer or detector (described in more detail below) at a viewing plane. The target and the viewing planes are focal planes of the lens. Target light reflected by the datum mirror is imaged on the viewing plane at unit magnification by the collimating lens. If the normal to the datum mirror is parallel to the optical axis of the autocollimator, then the target image is centered on the viewing plane. Any angular deviation of the normal from the optical axis manifests itself as a lateral displacement of the target image from the center. The magnitude of the displacement is proportional to the focal length and to the magnitude (assumed to be small) of the angular deviation. The direction of the displacement is perpendicular to the axis about which the mirror is slightly tilted. Hence, one can determine the amount and direction of tilt from the coordinates of the target image on the viewing plane.

Leviton, Douglas B.

2006-01-01

143

Exposure of rats to extremely low-frequency electromagnetic fields (ELF-EMF) alters cytokines production.  

PubMed

Investigations indicate a potential link between exposure to extremely low-frequency electromagnetic field (ELF-EMF) and some cancers. Carcinogenesis of ELF-EMF may be mediated by effect on the immune system. During an immune response, naïve T cells differentiate to effector type 1 helper T cells (T(H)1), T(H)2, or T(H)17 subsets according to existence of different cytokines and T(H)1 is important in defense against tumors. Therefore, it will be reasonable to test whether ELF-EMF can change cytokines like interferon gamma (IFN-?), interleukin-4 (IL-4), IL-6, and IL-12 that regulate T(H)1/T(H)2/T(H)17 balance. Forty adult male rats were randomly separated into ELF-EMF-exposed and sham-exposed control groups. The ELF-EMF group was exposed to a flux density of 100 ?T, frequency 50 Hz, 2 h/day for 3 months. The controls were placed in identical chamber without ELF-EMF. The results showed there were no significant differences between the mean mass of rats, thymuses, and spleens in ELF-EMF exposed group compared with controls. Serum IL-12 level was decreased from 418 ± 47 pg/ml in controls to 300 ± 23 pg/ml (p < 0.05) in ELF-EMF-exposed group. Phytohemagglutinin activated of in vitro production of IL-6 by the whole spleen culture (1356 ± 92 pg/ml) and total blood culture (418 ± 40 pg/ml) of ELF-EMF-exposed rats were higher (p < 0.001) comparing with controls (905 ± 74 pg/ml), (182 ± 26 pg/ml), respectively. However, the levels of IFN-?, IL-4, and IL-6 of serum and IFN-?, IL-4, and IL-12 in spleen culture and total blood culture of two groups were not significantly different. It seems that ELF-EMF may change T(H)1/T(H)2/T(H)17 balance toward down regulation of T(H)1 and upregulation T(H)17 type responses. PMID:23046051

Salehi, Iraj; Sani, Karim Ghazikhanlou; Zamani, Alireza

2013-03-01

144

ABSOLUTE POLARIMETRY AT RHIC.  

SciTech Connect

Precise and absolute beam polarization measurements are critical for the RHIC spin physics program. Because all experimental spin-dependent results are normalized by beam polarization, the normalization uncertainty contributes directly to final physics uncertainties. We aimed to perform the beam polarization measurement to an accuracy Of {Delta}P{sub beam}/P{sub beam} < 5%. The absolute polarimeter consists of Polarized Atomic Hydrogen Gas Jet Target and left-right pairs of silicon strip detectors and was installed in the RHIC-ring in 2004. This system features proton-proton elastic scattering in the Coulomb nuclear interference (CNI) region. Precise measurements of the analyzing power A{sub N} of this process has allowed us to achieve {Delta}P{sub beam}/P{sub beam} = 4.2% in 2005 for the first long spin-physics run. In this report, we describe the entire set up and performance of the system. The procedure of beam polarization measurement and analysis results from 2004-2005 are described. Physics topics of AN in the CNI region (four-momentum transfer squared 0.001 < -t < 0.032 (GeV/c){sup 2}) are also discussed. We point out the current issues and expected optimum accuracy in 2006 and the future.

OKADA; BRAVAR, A.; BUNCE, G.; GILL, R.; HUANG, H.; MAKDISI, Y.; NASS, A.; WOOD, J.; ZELENSKI, Z.; ET AL.

2007-09-10

145

NOVA: Absolute Zero  

NSDL National Science Digital Library

On a hot day, some might wish they could get the temperature down a bit. They might not wish it to be as cold as, say absolute zero, but there are many scientists who are interested in doing just that. For those who are curious, absolute zero clocks in at around minus 460 degrees Fahrenheit. This engaging website is meant to serve as a complementary resource to the two-part series that recently aired on NOVA on this engaging topic. Visitors can start by watching a short preview of the program, and then continuing on to look over some of the special interactive features on the site. All told, there are ten different features, including "A Sense of Scale", "How Low Can You Go?", and "Milestones in Cold Research". The "Milestones in Cold Research" is a great place to start, as it's an interactive timeline that chronicles the "netherworld of extraordinarily low temperatures" as investigated by everyone from Galileo to current researchers. Of course, there are also more playful features here, such as "The Ice Trade", which asks users to dispatch ships loaded with natural ice to Florida, Brazil, and India.

146

Features of the long-term photo emf relaxation in a heteroepitaxial ZnSe-GaAs structure  

Microsoft Academic Search

The spectral characteristics and transverse distribution of the photo emf were studied in a heteroepitaxial ZnSe-GaAs structure\\u000a obtained by MBE on a zinc-stabilized GaAs(100) substrate surface. The spectral measurements revealed unusual manifestations\\u000a of the long-term photo emf relaxation, whereby the amplitude of the spectral characteristic of the photo emf depends on the\\u000a direction of wavelength variation of the exciting monochromatic

L. V. Shekhovtsov; E. F. Venger; G. N. Semenova; Yu. G. Sadof’ev; N. E. Korsunskaya; M. P. Semtsiv; S. Yu. Sapko

2000-01-01

147

Variation in cancer risk estimates for exposure to powerline frequency electromagnetic fields: A meta-analysis comparing EMF measurement methods  

Microsoft Academic Search

We used meta-analysis to synthesize the findings from eleven case-control studies on cancer risks in humans exposed to 50-60 Hertz powerline electromagnetic fields (EMFs). Pooled estimates of risk are derived for different EMF measurement methods and types of cancer. EMF measurement methods are classified as: wiring configuration codes, distance to power distribution equipment, spot measurements of magnetic fields, and calculated

Michelle A. Miller; James R. Murphy; Thomas I Miller; A. J. Ruttenber

1995-01-01

148

A Back EMF Optimization of Double Layered Large-Scale BLDC Motor by Using Hybrid Optimization Method  

Microsoft Academic Search

This paper presents an optimization method of the back EMF for the double layered (double air gap) large-scale BLDC motor by using a Latin-hypercube sampling strategy. In order to drive the large-scale BLDC motors in parallel and multiphases, the back EMF of inner stator is equal to the back EMF of the outer. A new configuration of the double layered

Yong Bae Kim; Hong Soon Choi; Chang-Seop Koh; Pan Seok Shin

2011-01-01

149

Characterization of the DARA solar absolute radiometer  

NASA Astrophysics Data System (ADS)

The Davos Absolute Radiometer (DARA) prototype is an Electrical Substitution Radiometer (ESR) which has been developed as a successor of the PMO6 type on future space missions and ground based TSI measurements. The DARA implements an improved thermal design of the cavity detector and heat sink assembly to minimize air-vacuum differences and to maximize thermal symmetry of measuring and compensating cavity. The DARA also employs an inverted viewing geometry to reduce internal stray light. We will report on the characterization and calibration experiments which were carried out at PMOD/WRC and LASP (TRF).

Finsterle, W.; Suter, M.; Fehlmann, A.; Kopp, G.

2011-12-01

150

Absolute Equilibrium Entropy  

NASA Technical Reports Server (NTRS)

The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.

Shebalin, John V.

1997-01-01

151

Gene expression and reproductive abilities of male Drosophila melanogaster subjected to ELF-EMF exposure.  

PubMed

Extremely low frequency electromagnetic field (ELF-EMF) exposure is attracting increased attention as a possible disease-inducing factor. The in vivo effects of short-term and long-term ELF-EMF exposure on male Drosophila melanogaster were studied using transcriptomic analysis for preliminary screening and QRT-PCR for further verification. Transcriptomic analysis indicated that 439 genes were up-regulated and 874 genes were down-regulated following short-term exposures and that 514 genes were up-regulated and 1206 genes were down-regulated following long-term exposures (expression >2- or <0.5-fold, respectively). In addition, there are 238 up-regulated genes and 598 down-regulated genes in the intersection of short-term and long-term exposure (expression >2- or <0.5-fold). The DEGs (differentially expressed genes) in D. melanogaster following short-term exposures were involved in metabolic processes, cytoskeletal organization, mitotic spindle organization, cell death, protein modification and proteolysis. Long-term exposure let to changes in expression of genes involved in metabolic processes, response to stress, mitotic spindle organization, aging, cell death and cellular respiration. In the intersection of short-term and long-term exposure, a series of DEGs were related to apoptosis, aging, immunological stress and reproduction. To check the ELF-EMF effects on reproduction, some experiments on male reproduction ability were performed. Their results indicated that short-term ELF-EMF exposure may decrease the reproductive ability of males, but long-term exposures had no effect on reproductive ability. Down-regulation of ark gene in the exposed males suggests that the decrease in reproductive capacity may be induced by the effects of ELF-EMF exposure on spermatogenesis through the caspase pathway. QRT-PCR analysis confirmed that jra, ark and decay genes were down regulated in males exposed for 1 Generation (1G) and 72 h, which suggests that apoptosis may be inhibited in vivo. ELF-EMF exposure may have accelerated cell senescence, as suggested by the down-regulation of both cat and jra genes and the up-regulation of hsp22 gene. Up-regulation of totA and hsp22 genes during exposure suggests that exposed flies might induce an in vivo immune response to counter the adverse effects encountered during ELF-EMF exposure. Down-regulation of cat genes suggests that the partial oxidative protection system might be restrained, especially during short-term exposures. This study demonstrates the bioeffects of ELF-EMF exposure and provides evidence for understanding the in vivo mechanisms of ELF-EMF exposure on male D. melanogaster. PMID:24157427

Li, Si-Si; Zhang, Zi-Yan; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

2013-12-12

152

Effect of Extremely Low Frequency Electromagnetic Fields (EMF) on Phospholipase Activity in the Cultured Cells  

PubMed Central

This study was conducted to investigate the effects of extremely low frequency electromagnetic fields (EMF) on signal pathway in plasma membrane of cultured cells (RAW 264.7 cells and RBL 2H3 cells), by measuring the activity of phospholipase A2 (PLA2), phospholipase C (PLC) and phospholipase D (PLD). The cells were exposed to the EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h. The basal and 0.5 µM melittin-induced arachidonic acid release was not affected by EMF in both cells. In cell-free PLA2 assay, we failed to observe the change of cPLA2 and sPLA2 activity. Also both PLC and PLD activities did not show any change in the two cell lines exposed to EMF. This study suggests that the exposure condition of EMF (60 Hz, 0.1 or 1 mT) which is 2.4 fold higher than the limit of occupational exposure does not induce phospholipases-associated signal pathway in RAW 264.7 cells and RBL 2H3 cells.

Song, Ho Sun; Kim, Hee Rae; Ko, Myoung Soo; Jeong, Jae Min; Kim, Yong Ho; Kim, Myung Cheul; Hwang, Yeon Hee; Sohn, Uy Dong; Gimm, Yoon-Myoung; Myung, Sung Ho

2010-01-01

153

Electromagnetic fields and the public: EMF standards and estimation of risk  

NASA Astrophysics Data System (ADS)

Mobile communications are a relatively new and additional source of electromagnetic exposure for the population. Standard daily mobile-phone use is known to increase RF-EMF (radiofrequency electromagnetic field) exposure to the brains of users of all ages, whilst mobile-phone base stations, and base station units for cordless phones, can regularly increase the exposures of large numbers of the population to RF-EMF radiation in everyday life. The need to determine appropriate standards stipulating the maximum acceptable short-term and long-term RF-EMF levels encountered by the public, and set such levels as general guidelines, is of great importance in order to help preserve the general public's health and that of the next generation of humanity.

Grigoriev, Yury

2010-04-01

154

Universal 'imaginary closed circuit method' and formula for determination of direction of induced emf/current  

NASA Astrophysics Data System (ADS)

Fleming's right-hand rule and the right-flat-hand rule are generally applied for determining the direction of flow of induced emf/current in straight conductors. The right-hand-fingers rule is applied for coils only. The right-hand-thumb rule can be applied for either straight conductors or coils. Different rules have to be applied for different situations. Also, a formula for determining the direction of induced emf/current does not exist on the basis of these rules. In this article, based on Faraday's law of electromagnetic induction and Lenz's law, an 'imaginary closed circuit method' and a formula for determination of direction of induced emf/current has been proposed. The method is universal in the sense that it is applicable for conductors of any shape, for any kind of relative motion of the conductor with respect to the magnetic flux, and moreover it is applicable for the case of varying magnetic flux.

Balaram Atram, Dattatraya

2011-01-01

155

Absolute Norms on C n  

Microsoft Academic Search

In this paper, we study the absolute normalized norms on Cn. We show that the set of all absolute normalized norms on Cn is in one-to-one correspondence with the set ?n of all continuous convex functions on ?n with some suitable conditions, where ?n={(s1,…,sn?1)?Rn?1; s1+s2+···+sn?1?1, si?0 (1?i?n?1)}. As some applications, we show that an absolute norm on Cn is strictly

Kichi-Suke Saito; Mikio Kato; Yasuji Takahashi

2000-01-01

156

Absolute Zero: Science Educator's Guide  

NSDL National Science Digital Library

This guide provides recommendations for curricular modules on low temperature physics. Designed for teachers and informal educators of middle school students. this guide complements the Absolute Zero Community Education Outreach Guide. Suggestions on leading discussions, increasing student participation, and the use of inquiry are included. This material is related to a two-part public broadcasting special, Absolute Zero, produced by Meridian Productions and Windfall Films. Absolute Zero is underwritten by the National Science Foundation and the Alfred P. Sloan Foundation and is based largely on Tom Shachtmanâs acclaimed book, Absolute Zero and the Conquest of Cold.

2008-09-18

157

Safety of high speed guided ground transportation systems: EMF exposure environments. Summary report. Final report, January-June 1993  

Microsoft Academic Search

The paper presents an overview of American exposure assessments for electric and magnetic fields (EMF) in the frequency range from 0 to 3 kHz. The exposure information available is very limited for all but a few occupations and sources of EMF. Much of the exposure assessment done to date has been conducted in conjunction with epidemiological studies. Beyond the shortcomings

D. Goellner; T. Inge; L. Gillette; N. Hankin; B. Hostage

1993-01-01

158

Rapporteur Report: ICNIRP international workshop on EMF dosimetry and biophysical aspects relevant to setting exposure guidelines.  

PubMed

The International Commission on Non-Ionizing Radiation Protection has commenced the revision of its EMF guidelines in the frequency range up to 300 GHz. The ICNIRP International EMF Dosimetry Workshop has brought together a range of scientists to discuss the basis of the existing guidelines and to highlight those areas where attention needs to be given. This report is an attempt to extract the key messages from each of the presentations. A tabulation of the important issues discussed in the summary and conclusion session is provided at the end of this report. PMID:17495669

Roy, Colin R

2007-06-01

159

Relation between surface adsorption states and emf in a solid electrolyte concentration cell during carbon monoxide oxidation on platinum studied by local current measurement  

SciTech Connect

The importance of measuring adsorption during surface catalysis has been emphasized often. This is true for the oxidation of carbon monoxide on a platinum surface. Surface adsorption states during the reaction under steady states can be learned from electromotive force (emf) measurement with appropriate assumptions. Two mechanisms for emf generation have been proposed, one is that only oxygen activity generates emf, the other is that both oxygen and CO adsorption generates emf.

Okamoto, H.; Kawamura, G.; Kudo, T.

1984-04-01

160

Design aspects of a high-speed sensorless brushless dc motor using third harmonic back-emf for sensorless control  

NASA Astrophysics Data System (ADS)

There is increasing interest in high-speed permanent magnet (PM) brushless dc motors for a wide range of applications. Back-emf is often utilized for sensorless operation of permanent magnet brushless dc motors, by detecting the emf zero crossings. However, in high-speed motors, the free-wheeling diode conduction can last more than 30 e deg. This can obscure the zero crossings of the phase EMF; therefore, it is preferable to utilize the third harmonic emf instead of the phase emf. In this paper, some design aspects related to this high-speed sensorless operation are presented, including a special nonoverlapping winding arrangement and magnet segmenting technique. Finally, the experimental results confirmed the validity of the proposed design method.

Wang, Kai; Shen, Jianxin; Zhou, Fengzheng; Fei, Weizhong

2008-04-01

161

The impact of background radiation, illumination and temperature on EMF-induced changes of aqua medium properties.  

PubMed

The effects of extremely low frequency electromagnetic field (ELF EMF) on physicochemical properties of physiological solution at different environmental media were studied. The existence of frequency "windows" at 4 and 8 Hz frequencies of ELF EMF having effects on heat fusion period, hydrogen peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation and illumination was shown. Obtained data allow us to suggest that EMF-induced effect on water physicochemical properties depends on abovementioned environmental factors. As cell bathing medium is a target for biological effects of ELF EMF, the variability of experimental data on biological effects of EMF, obtained in different laboratories, can be explained by different environmental conditions of experiments, which very often are not considered adequately. PMID:23323624

Naira, Baghdasaryan; Yerazik, Mikayelyan; Anna, Nikoghosyan; Sinerik, Ayrapetyan

2013-09-01

162

Absolute Identification by Relative Judgment  

ERIC Educational Resources Information Center

In unidimensional absolute identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of absolute magnitudes. The authors propose an alternative…

Stewart, Neil; Brown, Gordon D. A.; Chater, Nick

2005-01-01

163

Electromagnetic fields (EMFs) and adenosine receptors modulate prostaglandin E(2) and cytokine release in human osteoarthritic synovial fibroblasts.  

PubMed

Synovial fibroblasts (SFs) contribute to the development of osteoarthritis (OA) by the secretion of a wide range of pro-inflammatory mediators, including cytokines and lipid mediators of inflammation. Previous studies suggest that electromagnetic fields (EMFs) may represent a potential therapeutic approach to limit cartilage degradation and control inflammation associated to OA, and that they may act through the adenosine pathway. Therefore, we investigated whether EMFs might modulate inflammatory activities of human SFs from OA patients (OASFs) treated with interleukin-1? (IL-1?), and the possible involvement of adenosine receptors (ARs) in mediating EMF effects. EMF exposure induced a selective increase in A(2A) and A(3) ARs. These increases were associated to changes in cAMP levels, indicating that ARs were functionally active also in EMF-exposed cells. Functional data obtained in the presence of selective A(2A) and A(3) adenosine agonists and antagonists showed that EMFs inhibit the release of prostaglandin E(2) (PGE(2)) and the proinflammatory cytokines interleukin-6 (IL-6) and interleukin-8 (IL-8), while stimulating the release of interleukin-10 (IL-10), an antinflammatory cytokine. These effects seem to be mediated by the EMF-induced upregulation of A(2A) and A(3) ARs. No effects of EMFs or ARs have been observed on matrix degrading enzyme production. In conclusion, this study shows that EMFs display anti-inflammatory effects in human OASFs, and that these EMF-induced effects are in part mediated by the adenosine pathway, specifically by the A(2A) and A(3) AR activation. Taken together, these results open new clinical perspectives to the control of inflammation associated to joint diseases. PMID:21830213

Ongaro, A; Varani, K; Masieri, F F; Pellati, A; Massari, L; Cadossi, R; Vincenzi, F; Borea, P A; Fini, M; Caruso, A; De Mattei, M

2012-06-01

164

Osteogenic differentiation of bone mesenchymal stem cells regulated by osteoblasts under EMF exposure in a co-culture system.  

PubMed

This study examined the osteogenic effect of electromagnetic fields (EMF) under the simulated in vivo conditions. Rat bone marrow mesenchymal stem cells (BMSCs) and rat osteoblasts were co-cultured and exposed to 50 Hz, 1.0 mT EMF for different terms. Unexposed single-cultured BMSCs and osteoblasts were set as controls. Cell proliferation features of single-cultured BMSCs and osteoblasts were studied by using a cell counting kit (CCK-8). For the co-culture system, cells in each group were randomly chosen for alkaline phosphatase (ALP) staining on the day 7. When EMF exposure lasted for 14 days, dishes in each group were randomly chosen for total RNA extraction and von Kossa staining. The mRNA expression of osteogenic markers was detected by using real-time PCR. Our study showed that short-term EMF exposure (2 h/day) could obviously promote proliferation of BMSCs and osteoblasts, while long-term EMF (8 h/day) could promote osteogenic differentiation significantly under co-cultured conditions. Under EMF exposure, osteogenesis-related mRNA expression changed obviously in co-cultured and single-cultured cells. It was noteworthy that most osteogenic indices in osteoblasts were increased markedly after co-culture except Bmp2, which was increased gradually when cells were exposed to EMF. Compared to other indices, the expression of Bmp2 in BMSCs was increased sharply in both single-cultured and co-cultured groups when they were exposed to EMF. The mRNA expression of Bmp2 in BMSCs was approximately four times higher in 8-h EMF group than that in the unexposed group. Our results suggest that Bmp2-mediated cellular interaction induced by EMF exposure might play an important role in the osteogenic differentiation of BMSCs. PMID:24710940

Yu, Ji-Zhe; Wu, Hua; Yang, Yong; Liu, Chao-Xu; Liu, Yang; Song, Ming-Yu

2014-04-01

165

Analytical Formula for the Torque\\/Emf Constant of a Slotless BLDC Motor  

Microsoft Academic Search

An original analytical formula for the torque\\/emf constant of a slotless brushless DC (BLDC) motor is presented. It is obtained by solving and integrating the permanent magnet field. In addition, formulas for the both stator and rotor iron fields are derived, in order to estimate the saturation level and losses. The results are verified using a FEM simulation

M. Markovic; Y. Perriard

2006-01-01

166

Analysis of EMF noise from the receiving coil topologies for wireless power transfer  

Microsoft Academic Search

Electromagnetic-field (EMF) noise from the only coil system with CSSR (Current source, Series resonance for TX, Series resonance for RX, and Resistive load) and CSPR (Current source, Series resonance for TX, Parallel resonance for RX, and Resistive load) topologies are featured in this paper. Wireless power transfer (WPT) system for a monitor is designed and analysed by using the equivalent

Jonghoon Kim; Hongseok Kim; Mijoo Kim; Seungyoung Ahn; Jiseong Kim; Joungho Kim

2012-01-01

167

Change in electrical resistivity and thermo-emf during the deformation of iron saturated with hydrogen  

Microsoft Academic Search

The electrical resistivity and thermo-emf were determined on wire specimens of Armco iron (i mm in diameter, 200 mm long) after annealing in vacuo at 930~ for 1 h. The specimens were deformed in air and during saturation with hydrogen on a laboratory testing machine at a rate of 2 mm\\/min. A 26% solution of sulfuric acid was used to

M. M. Shved; I. S. Slabkovskii; N. Ya. Yaremchenko; R. S. Kozemchuk; B. M. Yatsyk

1976-01-01

168

Can EMF exposure during development leave an imprint later in life?  

PubMed

People in industrialized nations live in an environment of ubiquitous electromagnetic field (EMF) exposure, both natural and anthropogenic. The intensity, variety, and geographic distribution of anthropogenic EMF exposures have grown dramatically since the mid 20th century, with many uses serving, and in close proximity to, human populations, such as electric power distribution, radio and television transmission, and more recently, personal cell phone communication units and transmitting towers. Thus, it is reasonable to ask if this EMF exposure could cause alterations in the physiology of developing organisms, since they are generally assumed to be the most sensitive to chemical stressors. In this report, we review work published beginning in the late 1980s. Initial reports indicated that exposure of chicken eggs during embryonic development to power-line electric fields of 50 and 60 Hz, at 10 V/m in air (which is frequently in locations inhabited by humans), could cause the brain tissues of the hatched chickens to respond differently in a particular test. More recently, an anecdotal report of human sensitivity to EMF has appeared that shows a health-related influence of prior exposure history to particular power-line frequencies in chemically sensitized individuals. These reports open the question of whether the ambient electromagnetic environment can leave an imprint on developing organisms and if such imprint changes have the potential for health consequences. PMID:17178582

Blackman, Carl F

2006-01-01

169

High Reliability Sheathed, Beryllia Insulated, Tungsten-Rhenium Alloy Thermocouple Assemblies; Their Fabrication and Emf Stability.  

National Technical Information Service (NTIS)

Tantalum sheathed, BeO insulated, W-3% Re/W-25% Re thermocouple assemblies were fabricated and their emf drift determined during 2059 hours of exposure at 2073 K in a gaseous helium environment. The sheathed thermocouple assemblies were constructed from a...

G. W. Burns W. S. Hurst M. G. Scroger

1974-01-01

170

Comment on ``Designing EMF experiments: What is required to characterize exposure?``  

Microsoft Academic Search

Dr. Valberg has taken an important step in describing what, at the present time, can be considered thorough documentation of exposure parameters in health effects studies related to EMFs. His paper provides important guidance for those entering the field and should serve as a reminder to more experienced investigators that good work can be rendered even more valuable by careful

B. Wilson

1995-01-01

171

SCHEME FOR INCORPORATING DC MAGNETIC FIELDS INTO EPIDEMIOLOGICAL STUDIES OF EMF EXPOSURE  

EPA Science Inventory

Experimental data on calcium-ion release in chicken brain tissue suggest that biological effects of electric and magnetic fields (EMFs) are concentrated at certain combinations of DC magnetic field strength and "critical" AC magnetic field frequencies. e hypothesize that "active"...

172

Analysis and Optimization of Back EMF Waveform of a Flux-Switching Permanent Magnet Motor  

Microsoft Academic Search

Flux-switching permanent magnet (FSPM) motors have a doubly salient structure, the magnets being housed in the stator and the stator winding comprising concentrated coils. They have attracted considerable interest due to their essentially sinusoidal phase back electromotive force (EMF) waveform. However, to date, the inherent nature of this desirable feature has not been investigated in detail. Thus, a typical three-phase

Wei Hua; Ming Cheng; Z. Q. Zhu; David Howe

2008-01-01

173

Comment on ``Designing EMF experiments: What is required to characterize exposure?``  

SciTech Connect

Dr. Valberg has taken an important step in describing what, at the present time, can be considered thorough documentation of exposure parameters in health effects studies related to EMFs. His paper provides important guidance for those entering the field and should serve as a reminder to more experienced investigators that good work can be rendered even more valuable by careful reporting. Evidence for the existence of biological effects from exposure to EMFs that may be encountered in residential and industrial environments is now sufficient to conclude that at least some of these effects are not artifacts. The EMF research community must now determine whether EMF biological effects can lead to adverse health effects in humans and, if so, show what field parameters are involved. This objective will be accomplished only through appropriately thought-out and well-documented observation and experimentation. An important implication of Valberg`s discussion is that engineering support in life science laboratories must be on a level sufficient to accurately determine the field parameters listed in the paper. Before the laboratory data can be fully utilized in achieving the overall objectives of EMF health effects research, personal dosimetry will have to be improved so that field parameters found to be important in laboratory studies can be either directly measured or accurately inferred. Such capability will require a new generation of lightweight portable smart dosimeters capable of continuously gathering magnetic field data over a wide range of frequencies. Over the next few years, Valberg`s long list of possible parameters should be narrowed to a short list of parameters that will merit intensive study in the laboratory and in human environments.

Wilson, B. [Pacific Northwest National Lab., Richland, WA (United States)

1995-12-31

174

Absolute gravity measurements in Indonesia  

NASA Astrophysics Data System (ADS)

For the purposes of the calibration of the superconducting gravimeter in Bandung and the establishment of the absolute gravity points, we have carried out absolute gravity measurements for the first time in Indonesia in November, 2002. We have been conducting a superconducting gravimeter (SG TT-70 #08) observation in Bandung since December 1997, under the cooperation between Kyoto University and the Volcanological Survey of Indonesia. It is one of the GGP observation points and the unique SG point near the equator. Hence the SG data are expected not only for the studies of solid earth dynamics but also for the studies of the fluid envelope (ocean, atmosphere, land water) in equatorial regions. However, the SG is a relative gravimeter and it inevitably requires calibration by means of an absolute gravimeter to ensure the scale factor and to determine instrumental drifts. Moreover, there was no absolute gravity point in Indonesia so far, therefore the realization of absolute gravity measurements in Indonesia had been strongly desired. We have carried out absolute gravity measurements in Bandung during Nov. 10 -19 by means of a FG5 (#210), and we obtained more than 29,000 effective drops. The gravity value newly determined at the gravity base point in Bandung is 977976701.9 uGal (1.e-8 m/s**2) and the scale factor for the SG is 52.281 uGal/V, although both values are still tentative and might be slightly revised in the future. We have also established another absolute gravity point in Yogyakarta near Merapi volcano. The absolute gravity measurements in Yogyakarta have been carried out during Nov. 22-26 and a tentative gravity value obtained is 978203091.9 uGal.

Fukuda, Y.; Higashi, T.; Takemoto, S.; Abe, M.; Sjafra, D.; Dendi, K.; Andan, A.; Doi, K.; Imanishi, Y.; Arguino, G.

2003-04-01

175

Application of EMF emission measurement techniques to wireless communications systems for compliance with directive 2004/40/EC.  

PubMed

Europe is the only region in the world with common legislative acts regulating exposure to electromagnetic fields (EMF) for both the general public and workers. Council Recommendation 1999/519/EC deals with the limitation of exposure of the general public to EMF (0 Hz-300 GHz). Directive 2004/40/EC regulates the minimum health and safety requirements regarding the exposure of workers to the risks arising from EMF. This paper discusses the general application of existing standards and recommendations in measurement techniques for determining compliance of measured exposure limit values and action values with those defined in 2004/40/EC. PMID:16790175

Simuni?, Dina; Gajsek, Peter

2006-01-01

176

Ionization Constants of T2O and D2O at 25° from Cell emf's. Interpretation of the Hydrogen Isotope Effects in emf's  

Microsoft Academic Search

The ionization constants of T2O and D2O were determined to be 6.1 × 10?16 and 1.43 × 10?15 at 25°, corresponding to K(H2O) ? K(T2O) = 16.4 and K(H2O) ? K(D2O) = 7.1 (concentrations in aquamolalities m?, moles of solute per 55.51 moles of isotopic water). Emf's were measured at 25° with X = H, D, and T for cells

Maxwell Goldblatt; Wesley M. Jones

1969-01-01

177

Effects of deformation on the thermo-EMF, resistivity, and X-ray emission spectra of iron  

Microsoft Academic Search

The study of the electrophysical properties of deformed metals is of interest because, in principle, it is possible to determine dislocation and vacancy concentrations and certain physical characteristics of these defects from resistivity and thermo-emf data [1-3]. To obtain such data it is necessary to know the way in which the resistivity Ap and the thermo-emf vary with the degree

N. Ya. Yaremchenko; R. S. Kozemchuk; I. S. Slabkovskii; M. M. Shved

1974-01-01

178

Novel back-EMF detection technique of brushless DC motor drives for whole duty-ratio range control  

Microsoft Academic Search

The main theme of this paper is to present a novel back-EMF detection technique which provides whole duty-ratio range control for brushless DC motor (BLDCM) drives. The problems for previous back-EMF detection techniques are clearly explained first. It will be shown that these techniques can be used either for low duty-ratio control or for high duty-ratio control only. The proposed

Yen-Shin Lai; Fu-Shan Shyu; Wei-Hwa Rao

2004-01-01

179

Design aspects of a high-speed sensorless brushless dc motor using third harmonic back-emf for sensorless control  

Microsoft Academic Search

There is increasing interest in high-speed permanent magnet (PM) brushless dc motors for a wide range of applications. Back-emf is often utilized for sensorless operation of permanent magnet brushless dc motors, by detecting the emf zero crossings. However, in high-speed motors, the free-wheeling diode conduction can last more than 30 e deg. This can obscure the zero crossings of the

Kai Wang; Jianxin Shen; Fengzheng Zhou; Weizhong Fei

2008-01-01

180

DIRECT OBSERVATION OF THE TURBULENT emf AND TRANSPORT OF MAGNETIC FIELD IN A LIQUID SODIUM EXPERIMENT  

SciTech Connect

For the first time, we have directly measured the transport of a vector magnetic field by isotropic turbulence in a high Reynolds number liquid metal flow. In analogy with direct measurements of the turbulent Reynolds stress (turbulent viscosity) that governs momentum transport, we have measured the turbulent electromotive force (emf) by simultaneously measuring three components of velocity and magnetic fields, and computed the correlations that lead to mean-field current generation. Furthermore, we show that this turbulent emf tends to oppose and cancel out the local current, acting to increase the effective resistivity of the medium, i.e., it acts as an enhanced magnetic diffusivity. This has important implications for turbulent transport in astrophysical objects, particularly in dynamos and accretion disks.

Rahbarnia, Kian; Brown, Benjamin P.; Clark, Mike M.; Kaplan, Elliot J.; Nornberg, Mark D.; Rasmus, Alex M.; Taylor, Nicholas Zane; Forest, Cary B. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave, Madison, WI 53706 (United States); Jenko, Frank; Limone, Angelo [Max-Planck-Institut fuer Plasmaphysik (IPP), EURATOM Association, D-85748 Garching (Germany); Pinton, Jean-Francois; Plihon, Nicolas; Verhille, Gautier, E-mail: kian.rahbarnia@ipp.mpg.de [Laboratoire de Physique de l'Ecole Normale Superieure de Lyon, CNRS and Universite de Lyon, F-69364 Lyon (France)

2012-11-10

181

Direct Observation of the Turbulent emf and Transport of Magnetic Field in a Liquid Sodium Experiment  

NASA Astrophysics Data System (ADS)

For the first time, we have directly measured the transport of a vector magnetic field by isotropic turbulence in a high Reynolds number liquid metal flow. In analogy with direct measurements of the turbulent Reynolds stress (turbulent viscosity) that governs momentum transport, we have measured the turbulent electromotive force (emf) by simultaneously measuring three components of velocity and magnetic fields, and computed the correlations that lead to mean-field current generation. Furthermore, we show that this turbulent emf tends to oppose and cancel out the local current, acting to increase the effective resistivity of the medium, i.e., it acts as an enhanced magnetic diffusivity. This has important implications for turbulent transport in astrophysical objects, particularly in dynamos and accretion disks.

Rahbarnia, Kian; Brown, Benjamin P.; Clark, Mike M.; Kaplan, Elliot J.; Nornberg, Mark D.; Rasmus, Alex M.; Zane Taylor, Nicholas; Forest, Cary B.; Jenko, Frank; Limone, Angelo; Pinton, Jean-François; Plihon, Nicolas; Verhille, Gautier

2012-11-01

182

EMF measurements on select transitions of the Li-Al/FeS/sub 2/ system  

SciTech Connect

The EMF vs. temperature curves were determined for the FeS/sub 2/ ..-->.. Li/sub 3/Fe/sub 2/S/sub 4/ and Li/sub 3/Fe/sub 2/S/sub 4/ ..-->.. Li/sub 2+x/Fe/sub 1-x/S/sub 2/ + Fe/sub 1-y/S transitions in LiCl-KCl eutectic over the temperature range 382/sup 0/-455/sup 0/C. The slopes for both transitions were found to be positive. The EMF data were used to determine the free energy of formation of Li/sub 3/Fe/sub 2/S/sub 4/ and the heat generation for each transition as a function of current density.

Tomczuk, Z.; Vissers, D.R.

1986-12-01

183

Survey and assessment of electric and magnetic field (EMF) public exposure in the transportation environment  

SciTech Connect

This research, conducted under the support of the Federal Electric and Magnetic Field Research and Public Information Dissemination (EMF RAPID) Engineering Program, characterized the extreme-low-frequency (ELF) electric and magnetic fields (EMF) which a traveler might encounter while using various forms of transportation. Extensive measurement of field level, frequency, temporal variability and spatial variability are reported for: conventional internal-combustion cars, trucks and buses; electric cars, trucks and buses; commuter trains; ferry boats; jetliners; airport shuttle trams; and escalators and moving sidewalks. Static magnetic field levels are also reported. Where possible, the source of the fields is identified. This effort extends extensive past work which investigated field in electrified trains, subways, light rail vehicles, and a magnetically levitated train by using similar protocols to characterize the complex ELF (3 Hz to 3000 Hz) electric and magnetic fields found in virtually all transportation systems.

Dietrich, F.M.; Jacobs, W.L.

1999-03-01

184

Analysis of standard reference materials by absolute INAA  

NASA Astrophysics Data System (ADS)

Three standard reference materials: flyash, soil, and ASI 4340 steel, are analyzed by a method of absolute instrumental neutron activation analysis. Two different light water pool-type reactors were used to produce equivalent analytical results even though the epithermal to thermal flux ratio in one reactor was higher than that in the other by a factor of two.

Heft, R. E.; Koszykowski, R. F.

1981-07-01

185

Back-EMF Detection Technique of Brushless DC Motor Drives for Wide Range Control  

Microsoft Academic Search

This paper presents a new back-EMF detection technique which provides wide range control for brushless DC motor (BLDCM) drives. As compared with previous techniques which can be used either for low duty-ratio control or for high duty-ratio control only, the proposed technique deals with the above-mentioned problem to give both low and high duty-ratio control while not invoking any position

Yen-Shin Lai; Yong-Kai Lin

2006-01-01

186

Automatic working primary standard of emf in the 1 to 10 V range  

Microsoft Academic Search

An automatic emf working primary standard in the 1 to 10 V range developed at the Scientific Production Association of the D. N. Mendeleev All-Union Scientific Research Institute of Metrology is described. The primary standard complies with GOST8.027-89 and its design is based on two groups often saturated standard cells each mounted in a single thermostat. The field of application,

V. Yu. Barbarovich; O. P. Galakhova; V. A. Zalepukhin; I. V. Korotkova; V. M. Simakhin; A. I. Smirnov

1993-01-01

187

Extended EMF observer for wide speed range sensorless control of salient-pole synchronous motor drives  

Microsoft Academic Search

This paper presents an observer-based position sensorless control method with signal injection. An extended electromotive force (EEMF) observer is suitable for salient-pole synchronous motors, because position information of EMF and saliency are both included. Signal injection is needed to make use of the position information of saliency at low speed. However, observer consists of a low-pass filter. Therefore, position information

Takumi Ohnuma; Shinji Doki; Shigeru Okuma

2010-01-01

188

Thermo-emf of Ni8 at. % Mo alloy in a wide temperature interval  

Microsoft Academic Search

perature range 100 to 1050~ and the electric resistivity p in the interval 20 to 1050~ The integrated thermo-emf of the alloy is measured on specimens in the form of 0.5 mm diameter wires by means of methods described in [2]. The total impurity content does not exceed 0.03%. Thermocouple-quality platinum which has previously undergone homogenization is used as reference

D. F. Kalinovich; I. I. Kovenskii; M. D. Smolin; V. M. Statsenko

1974-01-01

189

Stability of a synchronous generator with diode-bridge rectifier and back-EMF load  

Microsoft Academic Search

An equivalent circuit model of a synchronous generator with diode-bridge rectifier and back-EMF load is presented in this paper. The principle of harmonic balance is applied, which makes it possible to construct a state-space mathematical model for the system. The criterion of stability is obtained for the system under small disturbances. This stability criterion is more accurate than that presented

Ma Weiming; Hu An; Liu Dezhi; Zhang Gaifan

2000-01-01

190

Sensorless control of ultrahigh-speed PM brushless motor using PLL and third harmonic back EMF  

Microsoft Academic Search

Application-specific integrated circuit (ASIC) ML4425 is often used for sensorless control of permanent-magnet (PM) brushless direct current (BLDC) motor drives. It integrates the terminal voltage of the unenergized winding that contains the back electromotive force (EMF) information and uses a phase-locked loop (PLL) to determine the proper commutation sequence for the BLDC motor. However, even without pulsewidth modulation, the terminal

J. X. Shen; S. Iwasaki

2006-01-01

191

A full-wave motor drive IC based on the back-EMF sensing principle  

Microsoft Academic Search

A bipolar IC has been designed which allows full-wave driving of brushless three-phase DC motors. The three push-pull power stages operate in a switching mode. The commutation moments are directly derived from the zero-crossings of the back-EMF (electromotive force) in the floating motor windings. A start-up system will generate communications when no zero-crossing can be detected. A highly accurate tach-signal

J. P. M. Bahlmann

1989-01-01

192

Minimization of torque pulsations in a trapezoidal back-EMF permanent magnet brushless DC motor  

Microsoft Academic Search

This paper discusses the different methods used to reduce the torque pulsations (i.e. cogging torque and torque ripple) in a trapezoidal back-EMF permanent magnet (PM) brushless DC motor. The paper covers the design options to reduce both cogging torque and torque ripple. The effect of stator ampere-turns, the influence of rotor magnetization and the effect of the processing of electrical

Sunil Murthy; Benoit Derouane; Buyun Liu; Tomy Sebastian

1999-01-01

193

The Performance of a Single-Phase Current-Fed Inverter with Counter EMF - Inductive Load  

Microsoft Academic Search

Current-fed inverters that have series diodes to trap the charge on a commutating capacitor can supply ac loads of any power factor. A single-phase circuit with counter emf-inductance load, such as a motor, has been analyzed by digital computer simulation, valid for all modes of operation. The magnitude and phase of the ac load current are graphically related to the

William McMurray

1978-01-01

194

JWST Absolute Flux Calibration Plan  

NASA Astrophysics Data System (ADS)

The plan for the absolute flux calibration of all JWST instruments will be described. The science goal is to be able to predict the absolute flux of stars for all JWST instruments to sub-1% accuracy. A set of A0V, solar, and hot stars have been picked as a preliminary calibration sample. This calibration sample has been chosen specifically to provide at least 5 stars of each type in all the observing modes of each JWST instrument. In addition to existing Hubble and Spitzer observations, ground-based high-resolution spectroscopy will be obtained to provide strong, independent constraints on the best fitting model stellar atmospheres for each star.

Gordon, Karl D.; Bohlin, R.

2013-01-01

195

Absolute classification with unsupervised clustering  

NASA Technical Reports Server (NTRS)

An absolute classification algorithm is proposed in which the class definition through training samples or otherwise is required only for a particular class of interest. The absolute classification is considered as a problem of unsupervised clustering when one cluster is known initially. The definitions and statistics of the other classes are automatically developed through the weighted unsupervised clustering procedure, which is developed to keep the cluster corresponding to the class of interest from losing its identity as the class of interest. Once all the classes are developed, a conventional relative classifier such as the maximum-likelihood classifier is used in the classification.

Jeon, Byeungwoo; Landgrebe, D. A.

1992-01-01

196

Comparative study on electro-microfiltration (EMF) of water containing different carbon nanotubes (CNTs).  

PubMed

Disposal and penetration of carbon nanotubes (CNTs) into the environment have raised increasing concerns over the years. In this study, a laboratory scale electro-microfiltration (EMF) was used to treat water containing single wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs). The goal was to examine and compare the performance during EMF of SWCNT and MWCNT. The results showed that the initial flux was increased as the applied electrical voltage increased. At an applied pressure of 49 kPa, the final flux was comparable to pure water flux when the applied electrical field strength was greater than the critical electrical field strength (Ecritical). In addition, dissolved organic carbon (DOC) removal efficiency increased as the electrical voltage increased. Due to high convective transport of organic matter toward the membrane at 98 kPa, a decrease in DOC removal efficiency with increasing electrical field strength was observed. Overall, the fluxes and DOC removal efficiencies for EMF of SWCNT and MWCNT were not significantly different with a 95% confidence. PMID:23508148

Weng, Yu-Hsiang; Wu, Hsin-Chieh; Li, Kung-Cheh

2013-01-01

197

RF-EMF exposure of fetus and mother during magnetic resonance imaging  

NASA Astrophysics Data System (ADS)

Magnetic resonance imaging (MRI) avoids risks of genetic damage but may be associated with excess heating of body tissues. To investigate the exposure to MRI radio-frequency (RF) electromagnetic fields (EMF), low-pass and high-pass birdcage coils were simulated and the whole-body pregnant woman model SILVY used to determine local and whole-body specific absorption rates (SAR) in mother and fetus. Resonant RF-EMF of MRI devices were investigated at 0.3, 1, 1.5, 2, 3 and 4 T. Results allow extrapolation also to higher fields. They showed that local SAR in mother's trunk reaches exposure limits first. However, data show that during abdominal MRI meeting exposure limits of the mother is not sufficient to protect the fetus if limits of the general populations are applied to it. In that case fetal whole-body SAR exceeds limits by 7.4-fold. It is up to the physician and/or the ethics commission to decide upon justification for abdominal MRI of pregnant women if limits are exceeded. The results indicate the need for specifically addressing fetal exposure to EMF and elaborating general recommendations by radiation protection bodies.

Pediaditis, M.; Leitgeb, N.; Cech, R.

2008-12-01

198

EMF and public policy: Balancing interests of customers, shareholders, and the public  

SciTech Connect

Regulators and utilities will likely be under increasing pressure in the next few years, pending more conclusive evidence concerning EMF hazards, to establish standards designed to protect the public from harm and/or to protect the utility from future liability. The author noted that 3 conclusions can be drawn: (1) legislation or regulations establishing standards for exposure will not necessarily protect the utility that abides by such standards; (2) it is in the interest of both utilities and regulators to keep the public informed of all developments in the EMF area and to participate actively in research on the issue; and (3) the public may no longer be satisfied with a do nothing approach pending further evidence that EMF are harmful. The public's demand that the burden of proof be shifted to industry to ensure the safety of their products should be reflected in utility and regulators' obligations to respond to the public's demand for safe, as well as reasonably priced, electrical services.

Ross, D.J.

1991-04-01

199

Effects of electromagnetic fields (EMF) on the chemiluminescence (CL) of murine peritoneal exudate cells  

SciTech Connect

Stimulated PEC generate microbicidal free oxygen radicals which are potentially mutagenic and possibly carcinogenic. The effects of combined alternating electric and magnetic fields on oxygen radical production were measured in this study. A Helmholtz coil and parallel plate electrodes were utilized to provide uniform field characteristics. Effects were studied at combined field frequencies of 60, 600, and 6,000 Hz. Thioglycollate-elicited PEC were exposed to EMF or placed in a far corner of the lab (controls). Following the addition of zymosan, luminol-enhanced CL was measured. No differences in CL were found for exposures to 60 Hz for 18 hr; 600 Hz for 10 hr; or 6,000 Hz for 0.75 hr. PEC exposed to 6,000 Hz for 11 hr showed a 25% increase in CL over control PEC. At 600 and 6,000 Hz, the temperature of the air and a dish of saline in the EMF apparatus was 26C, vs. 25C where the controls were kept. At 60 Hz, there was no temperature difference. These preliminary experiments indicate that under these conditions, EMF fields do not have a significant effect on this immune function.

Caren, L.D. (California State Univ., Northridge (United States))

1992-02-26

200

Absolute pitch: Music and beyond  

Microsoft Academic Search

“Perfect pitch,” known in the scientific literature as “absolute pitch” (AP), is a rare phenomenon that has fascinated musicians and scientists alike for over a century. There has been a great deal of conflict in the literature between advocates of the two main theories on the etiology of AP: some believe that AP is learned early in life through intensive

David A. Ross; John C. Gore; Lawrence E. Marks

2005-01-01

201

Absolute transition probabilities of phosphorus.  

NASA Technical Reports Server (NTRS)

Use of a gas-driven shock tube to measure the absolute strengths of 21 P I lines and 126 P II lines (from 3300 to 6900 A). Accuracy for prominent, isolated neutral and ionic lines is estimated to be 28 to 40% and 18 to 30%, respectively. The data and the corresponding theoretical predictions are examined for conformity with the sum rules.-

Miller, M. H.; Roig, R. A.; Bengtson, R. D.

1971-01-01

202

Absolute focus lock for microscopes  

NASA Technical Reports Server (NTRS)

Mechanism absolutely immobilizes microscope stage at a preset focus, preserving focus indefinitely. The lock is a second-class lever consisting of a straight body having a fulcrum with a cylindrical bearing surface at one end and a thumbscrew at the other end.

Cone, C. D., Jr.; Loop, R. W.; Tongier, M., Jr.

1970-01-01

203

Absolute Pitch and Planum Temporale  

Microsoft Academic Search

An increased leftward asymmetry of the planum temporale (PT) in absolute-pitch (AP) musicians has been previously reported, with speculation that early exposure to music influences the degree of PT asymmetry. To test this hypothesis and to determine whether a larger left PT or a smaller right PT actually accounts for the increased overall PT asymmetry in AP musicians, anatomical magnetic

Julian Paul Keenan; Ven Thangaraj; Andrea R. Halpern; Gottfried Schlaug

2001-01-01

204

Non-thermal effects of EMF upon the mammalian brain: the Lund experience  

Microsoft Academic Search

The environment in which biology exists has dramatically changed during the last decades. Life was formed during billions\\u000a of years, exposed to, and shaped by the original physical forces such as gravitation, cosmic irradiation and the terrestrial\\u000a magnetism. The existing organisms are created to function in harmony with these forces. However, in the late 19th century\\u000a mankind introduced the use

Leif G. Salford; Henrietta Nittby; Arne Brun; Gustav Grafström; Jacob L. Eberhardt; Lars Malmgren; Bertil R. R. Persson

2007-01-01

205

Achieving Climate Change Absolute Accuracy in Orbit  

NASA Technical Reports Server (NTRS)

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission will provide a calibration laboratory in orbit for the purpose of accurately measuring and attributing climate change. CLARREO measurements establish new climate change benchmarks with high absolute radiometric accuracy and high statistical confidence across a wide range of essential climate variables. CLARREO's inherently high absolute accuracy will be verified and traceable on orbit to Système Internationale (SI) units. The benchmarks established by CLARREO will be critical for assessing changes in the Earth system and climate model predictive capabilities for decades into the future as society works to meet the challenge of optimizing strategies for mitigating and adapting to climate change. The CLARREO benchmarks are derived from measurements of the Earth's thermal infrared spectrum (5-50 micron), the spectrum of solar radiation reflected by the Earth and its atmosphere (320-2300 nm), and radio occultation refractivity from which accurate temperature profiles are derived. The mission has the ability to provide new spectral fingerprints of climate change, as well as to provide the first orbiting radiometer with accuracy sufficient to serve as the reference transfer standard for other space sensors, in essence serving as a "NIST [National Institute of Standards and Technology] in orbit." CLARREO will greatly improve the accuracy and relevance of a wide range of space-borne instruments for decadal climate change. Finally, CLARREO has developed new metrics and methods for determining the accuracy requirements of climate observations for a wide range of climate variables and uncertainty sources. These methods should be useful for improving our understanding of observing requirements for most climate change observations.

Wielicki, Bruce A.; Young, D. F.; Mlynczak, M. G.; Thome, K. J; Leroy, S.; Corliss, J.; Anderson, J. G.; Ao, C. O.; Bantges, R.; Best, F.; Bowman, K.; Brindley, H.; Butler, J. J.; Collins, W.; Dykema, J. A.; Doelling, D. R.; Feldman, D. R.; Fox, N.; Huang, X.; Holz, R.; Huang, Y.; Jennings, D.; Jin, Z.; Johnson, D. G.; Jucks, K.; Kato, S.; Kratz, D. P.; Liu, X.; Lukashin, C.; Mannucci, A. J.; Phojanamongkolkij, N.; Roithmayr, C. M.; Sandford, S.; Taylor, P. C.; Xiong, X.

2013-01-01

206

Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?  

PubMed Central

Background The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. Methods The study was carried out at the Kingsbridge 1 Wind Farm located near Goderich, Ontario, Canada. Magnetic field measurements were collected in the proximity of 15 Vestas 1.8 MW wind turbines, two substations, various buried and overhead collector and transmission lines, and nearby homes. Data were collected during three operational scenarios to characterize potential EMF exposure: ‘high wind’ (generating power), ‘low wind’ (drawing power from the grid, but not generating power) and ‘shut off’ (neither drawing, nor generating power). Results Background levels of EMF (0.2 to 0.3 mG) were established by measuring magnetic fields around the wind turbines under the ‘shut off’ scenario. Magnetic field levels detected at the base of the turbines under both the ‘high wind’ and ‘low wind’ conditions were low (mean = 0.9 mG; n = 11) and rapidly diminished with distance, becoming indistinguishable from background within 2 m of the base. Magnetic fields measured 1 m above buried collector lines were also within background (? 0.3 mG). Beneath overhead 27.5 kV and 500 kV transmission lines, magnetic field levels of up to 16.5 and 46 mG, respectively, were recorded. These levels also diminished rapidly with distance. None of these sources appeared to influence magnetic field levels at nearby homes located as close as just over 500 m from turbines, where measurements immediately outside of the homes were ? 0.4 mG. Conclusions The results suggest that there is nothing unique to wind farms with respect to EMF exposure; in fact, magnetic field levels in the vicinity of wind turbines were lower than those produced by many common household electrical devices and were well below any existing regulatory guidelines with respect to human health.

2014-01-01

207

No effects of intermittent 50 Hz EMF on cytoplasmic free calcium and on the mitochondrial membrane potential in human diploid fibroblasts  

Microsoft Academic Search

The recently described increase in DNA strand breaks of cultured human diploid fibroblasts after intermittent exposure to extremely-low-frequency electromagnetic fields (ELF-EMF) of more than about 70 µT ELF-EMF is difficult to explain by a direct induction of covalent bond disruption. Therefore the hypothesis has been tested that ELF-EMF-induced DNA strand breaks might be mediated by cellular processes that cause alteration of

Alexander Pilger; Sabine Ivancsits; Elisabeth Diem; Melanie Steffens; Hans-Albert Kolb; Hugo W. Rüdiger

2004-01-01

208

Safety of high speed guided ground transportation systems. Broadband magnetic fields: Their possible role in EMF-associated bioeffects. Final report, January 1993-June 1993  

SciTech Connect

The report reviews electric and magnetic field (EMF) exposures from electrical transportation systems, including electrically powered rail and magnetic levitation (maglev). Material also covered includes research concerning biological effects of EMF exposure, with special emphasis on broad spectrum or broadband magnetic fields. A primary objective of the report was to consider, based on present knowledge, the potential for adverse health effects from maglev-associated EMF. Because maglev technology is known to generate magnetic fields at a variety of frequencies, the document addresses the broadband EMF frequency characteristics (including pulses, intermittent fields, and other transient phenomena).

Goellner, D.; Wilson, B.; Reiter, R.; Pilla, A.; Hankin, N.

1993-08-01

209

Absolute-Gravity Workshop planned  

NASA Astrophysics Data System (ADS)

The new FG5 absolute gravimeter has a design goal accuracy of 1 ?Gal and represents the most recent of a series of gravimeters inspired by advances in gravimeter design by J. Faller at the Joint Institute for Laboratory Astrophysics (JILA) in Boulder, Colo. A 2-day workshop will be held in Boulder from March 22 to 23 to discuss current and future applications of absolute gravity (g). Details of the workshop appear at the end of this article. The instrument is based on the principle of interferometrically measuring the time and position of a weight falling in a vacuum, using a stabilized laser and an atomic clock [cf. Cook, 1967; Faller, 1963; Hammond, 1970; Zumberge, 1981; Niebauer, 1986].

Bilham, Roger; Sasagawa, Glenn

210

Absolute light output of scintillators  

Microsoft Academic Search

The absolute light outputs of BGO, CsI(Tl) and some new Ce-doped crystals have been measured to an accuracy of about ±5% using calibrated XP2020Q photomultipliers and standard S3590.03 and S2740.03 photodiodes. The use of small crystals, 9 mm in diameter and 1 mm thick, reduces the corrections for imperfections in the light collection process and in the photoelectron collection by

M. Moszynski; M. Kapusta; M. Mayhugh; D. Wolski; S. O. Flyckt

1997-01-01

211

Absolute Radiometric Calibration of SERTS  

NASA Astrophysics Data System (ADS)

The Solar EUV Rocket Telescope and Spectrograph (SERTS) obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. We have recently carried out a complete end-to-end calibration of the instrument to determine its absolute radiometric response over the full bandpass of 300 -- 365 Angstroms. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibration of the Coronal Diagnostic Spectrometer (CDS) experiment now flying aboard the SOHO spacecraft. For our SERTS project, the unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) in Germany was re-calibrated to an absolute accuracy of 7% (1sigma ) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is a primary radiometric source standard. Scans of the SERTS aperture over a range of pitch and yaw angles were made to determine the instrument's absolute spectral sensitivity to <= 25%, considering all sources of error. These results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted `insensitive' line ratios. The recent measurements at RAL also give information about the uniformity of illumination across the collimated source beam, as well as about polarization characteristics of both the instrument and radiation source, which may prove helpful in correctly interpreting the original CDS calibration data. We hope to repeat such calibration measurements and to provide future SERTS flights annually, at least throughout the duration of the SOHO mission. Coordinated observing programs would then allow these updated absolute calibrations to be transferred on a regular basis to several of the instruments onboard SOHO, including CDS, EIT, and CELIAS.

Thomas, R. J.; Condor, C. E.; Haas, J. P.; Linard, D. L., II; Swartz, M.; Kent, B. J.; Hollandt, J.

1997-12-01

212

Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption.  

PubMed

A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light. PMID:22319353

Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

2011-01-01

213

Thermodynamic properties of liquid silver–indium alloys determined from e.m.f. measurements  

Microsoft Academic Search

The thermodynamic properties of the liquid Ag–In alloys were determined using solid oxide galvanic cells with zirconia electrolyte. The e.m.f.'s of the cellsRe+kanthal,AgxIn(1?x),In2O3\\/\\/ZrO2+(Y2O3)\\/\\/NiO,Ni,Ptwere measured in the temperature range from 950 to 1273K, and in the molar fraction from xIn=0.15 to 1.0.At first, the Gibbs free energy of formation of pure solid indium oxide, In2O3, from pure elements was derived. Using

Dominika Jendrzejczyk; Krzysztof Fitzner

2005-01-01

214

Higher order concentration moments collapse in the expected mass fraction (EMF) based risk assessment  

NASA Astrophysics Data System (ADS)

In this work Langrangian framework is used for conservative tracer transport simulations through 2-D extremely heterogeneous porous media. Conducted numerical simulations enable large sets of concentration values in both spatial and temporal domains. In addition to the advection, which acts on all scales, an additional mechanism considered is local scale dispersion (LSD), accounting for both mechanical dispersion and molecular diffusion. The ratio between these two mechanisms is quantified by the Peclet (Pe) number. In its base, the work gives answers to concentration scalar features when influenced by: i) different log-conductivity variance; ii) log-conductivity structures defined by the same global variogram but with different log conductivity patterns correlated; and iii) for a wide range of Peclet values. Results conducted by Monte Carlo analysis show a complex interplay between the aforementioned parameters, indicating the influence of aquifer properties to temporal LSD evolution. A remarkable collapse of higher order to second-order concentration moments [Yee, 2009] leads to the conclusion that only two concentration moments are required for an accurate description of concentration fluctuations. This explicitly holds for the pure advection case, while in the case of LSD presence the moment deriving function(MDF) is involved to ensure the moment collapse validity. An inspection of the Beta distribution leads to the conclusion that the two-parametric distribution can be used for concentration fluctuation characterization even in cases of high aquifer heterogeneity and/or for different log-conductivity structures, independent of the sampling volume used. Furthermore, the expected mass fraction (EMF) [Heagy & Sullivan, 1996] concept is applied in groundwater transport. In its origin, EMF is function of the concentration but with lower number of realizations needed for its determination, compared to the one point PDF. From practical point of view, EMF excludes meandering effect and incorporates information about exposure time for each non-zero concentration value present. Also, it is shown that EMF is able to clearly reflect the effects of aquifer heterogeneity and structure as well as the Pe value. The latter is demonstrated through the non-carcinogenic risk assessment framework. To demonstrate the uniqueness of the moment collapse feature and ability of the Beta distribution to account for the concentration frequencies even in real cases, Macrodispersion Experiment (MADE1) [Boggs et al, 1992] data sets are used for validation.

Srzic, Veljko; Gotovac, Hrvoje; Cvetkovic, Vladimir; Andricevic, Roko

2014-05-01

215

Familial aggregation of absolute pitch.  

PubMed

Absolute pitch (AP) is a behavioral trait that is defined as the ability to identify the pitch of tones in the absence of a reference pitch. AP is an ideal phenotype for investigation of gene and environment interactions in the development of complex human behaviors. Individuals who score exceptionally well on formalized auditory tests of pitch perception are designated as "AP-1." As described in this report, auditory testing of siblings of AP-1 probands and of a control sample indicates that AP-1 aggregates in families. The implications of this finding for the mapping of loci for AP-1 predisposition are discussed. PMID:10924408

Baharloo, S; Service, S K; Risch, N; Gitschier, J; Freimer, N B

2000-09-01

216

Absolute D hadronic branching fractions  

NASA Astrophysics Data System (ADS)

Using 281 pb-1 of e^+e^- collisions recorded at the ?(3770) resonance with the CLEO-c detector at CESR, we determine absolute hadronic branching fractions of charged and neutral D mesons using a double tag technique. Among measurements for three D^0 and six D^+ modes, we measure reference branching fractions B(D^0 ->K^- +circ) and B(D^+ ->K^- +circ+circ). Using a determination of the integrated luminosity, we also extract the cross sections ?(e^+e^- ->D^0 D^0) and ?(e^+e^- ->D^+D^-).

Shi, Xin

2007-04-01

217

Variation in cancer risk estimates for exposure to powerline frequency electromagnetic fields: A meta-analysis comparing EMF measurement methods  

SciTech Connect

We used meta-analysis to synthesize the findings from eleven case-control studies on cancer risks in humans exposed to 50-60 Hertz powerline electromagnetic fields (EMFs). Pooled estimates of risk are derived for different EMF measurement methods and types of cancer. EMF measurement methods are classified as: wiring configuration codes, distance to power distribution equipment, spot measurements of magnetic fields, and calculated indices based on distance to power distribution equipment and historic load data. Pooled odds ratios depicting the risk of cancer by each measurement type are presented for all cancers combined, leukemia for all age groups and childhood leukemia. The wire code measurement technique was associated with a significantly increased risk for all three cancer types, while spot measures consistently showed non-significant odds ratios. Distance measures and the calculated indices produced risk estimates which were significant only for leukemia. 24 refs., 6 tabs.

Miller, M.A.; Murphy, J.R.; MIller, T. I; Ruttenber, A.J. [Univ. of Colorado Health Sciences Center, Denver, CO (United States)

1995-04-01

218

Safety of high speed guided ground transportation systems: EMF exposure environments. Summary report. Final report, January-June 1993  

SciTech Connect

The paper presents an overview of American exposure assessments for electric and magnetic fields (EMF) in the frequency range from 0 to 3 kHz. The exposure information available is very limited for all but a few occupations and sources of EMF. Much of the exposure assessment done to date has been conducted in conjunction with epidemiological studies. Beyond the shortcomings of using some of the published epidemiology studies, there are some serious obstacles to conducting definitive extreme low frequency (ELF)-EMF exposure assessments. The lack of a clear definition of what constitutes effective dose hampers the measurement of exposure considerably. Generally, the average power frequency magnetic flux density has been assumed to be the exposure measure of significance, however other parameters of the magnetic field are likely to be relevant as well.

Goellner, D.; Inge, T.; Gillette, L.; Hankin, N.; Hostage, B.

1993-08-01

219

EMF changes of Pt\\/Pd thermocouples in the range from 420\\/spl deg\\/C to 1080\\/spl deg\\/C  

Microsoft Academic Search

Drifts in EMF of Pt\\/Pd thermocouples at Cu, Ag, Al and Zn freezing points were measured. Different heat treatments were applied to thermocouples before the calibrations. The measured results showed that large emf changes appeared at Cu and Ag freezing points, and the magnitude of the drift and inhomogeneity were dependent on the final step of the heat treatment method.

Hideki Ogura; Haruhiko Numajiri; Hirokazu Narushima; Masaya Izuchi; Masaru Arai

2003-01-01

220

Safety of high speed guided ground transportation systems: Review of existing EMF guidelines, standards and regulations. Final report, January-June 1993  

Microsoft Academic Search

Although there are no maglev or other advanced high-speed rail systems currently operating in the United States, EMF exposure is still of concern as it relates top 60 hertz (Hz) power transmission and distribution lines and electrical appliances. The report provides information on existing and proposed EMF guidelines, standards and regulations at the international, national, state, and local levels. It

D. Goellner; B. Wilson; R. Reiter; A. Pilla; N. Hankin

1993-01-01

221

Standard molar Gibbs free energy of formation of PbO(s) over a wide temperature range from EMF measurements  

Microsoft Academic Search

The EMF of the following galvanic cells, (Cell(I))Kanthal,Re,Pb,PbO?CSZ?O2(1atm.),Pt(Cell(II))Kanthal,Re,Pb,PbO?CSZ?O2(1atm.),RuO2,Ptwere measured as a function of temperature. With O2 (1 atm.), RuO2 as the reference electrode, measurements were possible at low temperatures close to the melting point of Pb. Standard Gibbs energy of formation, ?fG0m??-PbO? was calculated from the emf measurements made over a wide range of temperature (612–1111 K) and is given

Rajesh Ganesan; T. Gnanasekaran; Raman S. Srinivasa

2003-01-01

222

Standard Gibbs energy of formation of Mo 3Te 4 by emf measurements  

NASA Astrophysics Data System (ADS)

The emf of the galvanic cells Pt, Mo, MoO 2¦8 YSZ¦'FeO', Fe, Pt (I) and Pt, Fe,'FeO' ¦8 YSZ¦MoO 2, Mo 3Te 4, MoTe 2(?), C, Pt (II) were measured over the temperature ranges 837 to 1151 K and 775 to 1196 K, respectively, using 8 mass% yttria-stabilized zirconia (8 YSZ) as the solid electrolyte. From the emf values, the partial molar Gibbs energy of solution of molybdenum in Mo 3Te 4/MoTe 2(?), ? ?Mo was found to be ? ?Mo ± 1.19 ( kJ/mol) = -025.08 + 0.00420T(K) . Using the literature data for the Gibbs energy of formation of MoTe 2(?). the expression ?G° f( Mo3Te4, s) ± 5.97 (kj/mol) = -253.58 + 0.09214 T( K) was derived for the range 775 to 1196 K. A third-law analysis yielded a value of -209 ± 10 kJ/mol for ?H° f.298o of Mo 3Te 4(s).

Mallika, C.; Sreedharan, O. M.

1990-03-01

223

Effects of 940 MHz EMF on bioluminescence and oxidative response of stable luciferase producing HEK cells.  

PubMed

The effects of mobile phone frequency electromagnetic field (RF-EMF, 940 MHz) on a stable cell line (HEK293T) harbouring the firefly luciferase gene were evaluated. A waveguide exposure system with 1 W input power provided the mean specific absorption rate of ?0.09 W kg(-1) in 35 mm Petri dishes. The effects of exposure duration (15, 30, 45, 60 and 90 min) on luciferase activity and oxidative response elements were investigated. Endogenous luciferase activity was reduced after 30 and 45 min of continuous exposure, while after 60 min, the exposed cell lysate showed higher luciferase activity compared with the non-exposed control. Reactive oxygen species (ROS) generation was highest in the 30 min exposed cells as studied by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence. The observed boost in ROS was then followed by a sharp rise in catalase (CAT) and superoxide dismutase (SOD) activity and elevation of glutathione (GSH) during the 45 min exposure. Decrease in lipid peroxidation (malondialdehyde, MDA) was meaningful for the 45 and 60 min exposed cells. Therefore, it appears that an increase in the activity of luciferase after 60 min of continuous exposure could be associated with a decrease in ROS level caused by activation of the oxidative response. This ability in cells to overcome oxidative stress and compensate the luciferase activity could also be responsible for the adaptive response mechanism detected in ionizing radiation studies with RF-EMF pre-treatments. PMID:24886806

Sefidbakht, Yahya; Moosavi-Movahedi, Ali Akbar; Hosseinkhani, Saman; Khodagholi, Fariba; Torkzadeh-Mahani, Masoud; Foolad, Forough; Faraji-Dana, Reza

2014-07-18

224

A study on systematic errors concerning rotor position estimation of PMSM based on back EMF voltage observation  

Microsoft Academic Search

Many published methods of rotor position estimation of permanent magnet synchronous machines (PMSM) for medium to high speed are based on the estimation of the back electromotive force (EMF) voltage. From a practical point of view and the demand of minimum complexity, a simple idealized motor model is used many times. Due to this simplification and to a change of

P. Hutterer; H. Grabner; S. Silber; W. Amrhein; W. Schaefer

2009-01-01

225

Magnetic field design for high efficient and low EMF wireless power transfer in on-line electric vehicle  

Microsoft Academic Search

In this paper, we introduce the On-Line Electric Vehicle (OLEV) system and its non-contact power transfer mechanism. We propose the design methodology to maximize the wireless power transfer capability and power transfer efficiency and to minimize the electromagnetic field (EMF) from the wireless power transfer system in OLEV. By using the series resonant power transfer topology and vertical magnetic flux

Seungyoung Ahn; Joungho Kim

2011-01-01

226

A Meta-Analysis on the Relationship between Exposure to ELF-EMFs and the Risk of Female Breast Cancer  

PubMed Central

Objective To comprehensively analyze the relationship between exposure to extremely low frequency electromagnetic fields (ELF-EMFs) and the development of female breast cancer. Methods Reports of case-control studies published from 1990 to 2010 were analyzed. The quality effect model was chosen to calculate total odds ratio (OR) depending on the data in studies and quality scores. Subgroup analyses were also performed by the situation of menopause, estrogenic receptor and exposure assessment respectively. Results For all 23 studies the OR was 1.07, 95% CI?=?1.02–1.13, for estrogen receptor positive subgroup,OR?=?1.11, 95% CI?=?1.03–1.20; for premenopausal subgroup, OR?=?1.11, 95% CI?=?1.00–1.23. The results of other subgroups showed no significant association between ELF-EMF and female breast cancer. Conclusion ELF-EMFs might be related to an increased risk for female breast cancer, especially for premenopausal and ER+ females. However, it's necessary to undertake better epidemiologic researches to verify the association between ELF-EMF and female breast cancer due to the limits of current study, especially the one on exposure assessment.

Chen, Qingsong; Lang, Li; Wu, Wenzhe; Xu, Guoyong; Zhang, Xiao; Li, Tao; Huang, Hanlin

2013-01-01

227

Minimization of higher back-EMF harmonics in permanent magnet motor using shape design sensitivity with B-spline parameterization  

Microsoft Academic Search

This paper presents a shape optimal design method for reducing the higher back-EMF harmonics generated in the permanent magnet motors, in which torque ripples could occur. The continuum shape design sensitivity formula and the finite element method are employed to calculate the sensitivity of flux-linkage to the design variables, which determine the shape of iron pole piece. The design variables

Joon-Ho Lee; Dong-Hun Kim; Il-Han Park

2003-01-01

228

Impact of Maximum Back-EMF Limits on the Performance Characteristics of Interior Permanent Magnet Synchronous Machines  

Microsoft Academic Search

Interior permanent magnet (IPM) synchronous machines are vulnerable to uncontrolled generator (UCG) faults at high speed that can damage the inverter. One approach to reducing this risk is to impose limits on the maximum machine back-EMF voltage at top speed. This paper presents the results of a comparative design study that clarifies the nature and extent of the penalties imposed

Seok-Hee Han; T. M. Jahns; M. K. Guven; M. Aydin; W. L. Soong

2006-01-01

229

Position-sensorless biaxial position control with industrial PM motor drives based on INFORM and back EMF model  

Microsoft Academic Search

In the presented paper the practical realization of a position sensorless biaxial positioning system based on industrial permanent magnet synchronous motor (PMSM) drives is introduced. At low speed including standstill the INFORM-method is used for sensorless position estimation, at high speed an EMF-based short circuit model is applied. With the help of a proper control structure and a corresponding implementation

Ewald Robeischl; Manfi-ed Schroedl; Michael Krammer

2002-01-01

230

Speed control of permanent magnet motors using sliding mode observers for induced EMF position and speed estimation  

Microsoft Academic Search

This paper presents a speed control system for a permanent magnet synchronous motor (PMSM) in which the sliding mode technique is used to estimate the induced EMF, rotor position and speed. The electrical dynamic equations of PMSM are modified to obtain the sliding mode observer model and then the variables are estimated by using only measured stator currents and voltages.

Zelia M. A. Peixoto; Flavia M. F. Sa; P. F. Seixas; Benjamin R. Menezes; Porfirio C. Cortizo

1995-01-01

231

Contending discourses in the electric and magnetic fields controversy: The social construction of EMF risk as a public problem  

Microsoft Academic Search

The issue of adverse health effects from electric and magnetic fields (EMFs) has been brewing for the last decade or so. While the epidemiological evidence persists in linking proximity-to-powerlines to a few forms of cancer, exposure and dose remain undefined, and no clear mechanism of action has been identified. Despite this scientific ambiguity, there are frequent calls for governmental action;

Stephen H. Linder

1995-01-01

232

Normoblastemia after Thermal Injury.  

National Technical Information Service (NTIS)

The peripheral blood smears of 214 thermally injured patients studied during a thirty month period revealed a 20 percent incidence of normoblastemia (51 patients). Nucleated red blood cells were most common in patients with the largest burns. The absolute...

W. A. Andes

1976-01-01

233

Frequency-domain analysis of absolute gravimeters  

NASA Astrophysics Data System (ADS)

An absolute gravimeter is analysed as a linear time-invariant system in the frequency domain. Frequency responses of absolute gravimeters are derived analytically based on the propagation of the complex exponential signal through their linear measurement functions. Depending on the model of motion and the number of time-distance coordinates, an absolute gravimeter is considered as a second-order (three-level scheme) or third-order (multiple-level scheme) low-pass filter. It is shown that the behaviour of an atom absolute gravimeter in the frequency domain corresponds to that of the three-level corner-cube absolute gravimeter. Theoretical results are applied for evaluation of random and systematic measurement errors and optimization of an experiment. The developed theory agrees with known results of an absolute gravimeter analysis in the time and frequency domains and can be used for measurement uncertainty analyses, building of vibration-isolation systems and synthesis of digital filtering algorithms.

Svitlov, S.

2012-12-01

234

Efficiency determination and general characterization of thermoelectric generators using an absolute measurement of the heat flow  

Microsoft Academic Search

An apparatus for measuring the conversion efficiency ? and several further key properties of thermoelectric generators is presented. To achieve highest reliability and accuracy the crucial determination of the thermal energy that is supplied to the generator is done by an absolute method, i.e. by measuring the electrical power that is dissipated in a thermally guarded resistive heater. The accuracy

L Rauscher; S Fujimoto; H T Kaibe; S Sano

2005-01-01

235

Analysis of cell performance and thermal regeneration of a lithium-tin cell having an immobilized fused-salt electrolyte  

NASA Technical Reports Server (NTRS)

Cell performance and thermal regeneration of a thermally regenerative cell uses lithium and tin and a fused-salt electrolyte. The emf of the Li-Sn cell, as a function of cathode-alloy composition, is shown to resemble that of the Na-Bi cell.

Cairns, E. J.; Shimotake, H.

1969-01-01

236

Extended EMF Models of Synchronous Reluctance Motors and Selection of Main Flux Direction  

NASA Astrophysics Data System (ADS)

A new mathematical model called an Extended EMF (EEMF) model and a sensorless control method using the concept for PMSMs have proposed by authors, and their availability have been verified by experiments. The purpose of this paper is to apply the EEMF model to sensorless control of synchronous reluctance motors. Since synchronous reluctance motors do not have any permanent magnet, a main flux direction of a motor model can be chosen in two ways. And the difference of the main flux direction leads to two EEMF models. Between two EEMF models, there is some difference from the point of the motor model for sensorless control. We indicate the difference of two EEMF models clearly and derive the difference of the position estimation error caused by deviation of inductance parameters. Moreover, the selection way of EEMF models is discussed. Finally, the selection method is verified by experiments.

Ichikawa, Shinji; Tomita, Mutuwo; Doki, Shinji; Okuma, Shigeru; Fujiwara, Fumiharu

237

OPC model prediction capability improvements by accounting for mask 3D-EMF effects  

NASA Astrophysics Data System (ADS)

As mask feature sizes have shrunk well below the exposure wavelength, the thin mask of Kirchhoff approximation breaks down and 3D mask effects contribute significantly to the through-focus CD behavior of specific features. While full-chip rigorous 3D mask modeling is not computationally feasible, approximate simulation methods do enable the 3D mask effects to be represented. The use of such approximations improves model prediction capability. This paper will look at a 28nm darkfield and brightfield layer datasets that were calibrated with a Kirchhoff model and with two different 3D-EMF models. Both model calibration accuracy and verification fitness improvements are realized with the use of 3D models.

Cheng, Jacky; Schramm, Jessy; Zhang, Dong Qing; Foong, Yee Mei; Zuniga, Christian; Do, Thuy; Tejnil, Edita; Sturtevant, John; Chung, Angeline; Jantzen, Kenneth

2012-03-01

238

Insights from EMF Associated Agricultural and Forestry Greenhouse Gas Mitigation Studies  

SciTech Connect

Integrated assessment modeling (IAM) as employed by the Energy Modeling Forum (EMF) generally involves a multi-sector appraisal of greenhouse gas emission (GHGE) mitigation alternatives and climate change effects typically at the global level. Such a multi-sector evaluation encompasses potential climate change effects and mitigative actions within the agricultural and forestry (AF) sectors. In comparison with many of the other sectors covered by IAM, the AF sectors may require somewhat different treatment due to their critical dependence upon spatially and temporally varying resource and climatic conditions. In particular, in large countries like the United States, forest production conditions vary dramatically across the landscape. For example, some areas in the southern US present conditions favorable to production of fast growing, heat tolerant pine species, while more northern regions often favor slower-growing hardwood and softwood species. Moreover, some lands are currently not suitable for forest production (e.g., the arid western plains). Similarly, in agriculture, the US has areas where citrus and cotton can be grown and other areas where barley and wheat are more suitable. This diversity across the landscape causes differential GHGE mitigation potential in the face of climatic changes and/or responses to policy or price incentives. It is difficult for a reasonably sized global IAM system to reflect the full range of sub-national geographic AF production possibilities alluded to above. AF response in the face of climate change altered temperature precipitation regimes or mitigation incentives will likely involve region-specific shifts in land use and agricultural/forest production. This chapter addresses AF sectoral responses in climate change mitigation analysis. Specifically, we draw upon US-based studies of AF GHGE mitigation possibilities that incorporate sub-national detail drawing largely on a body of studies done by the authors in association with EMF activities. We discuss characteristics of AF sectoral responses that could be incorporated in future IAM efforts in climate change policy.

McCarl, Bruce A.; Murray, Brian; Kim, Man-Keun; Lee, Heng-Chi; Sands, Ronald D.; Schneider, Uwe

2007-11-19

239

Lack of an EMF-induced genotoxic effect in the Ames assay  

SciTech Connect

A few epidemiological studies have linked exposure to electromagnetic fields (EMF) and the incidence of cancer. Since many carcinogens are mutagens in the Ames assay, the purpose of this study was to determine if exposure of four tester strains of Salmonella typhimurium (TA97a, TA98, TA100, and TA102) to EMF would increase their rate of mutation. Parallel plate electrodes and Helmholtz coils were used to create uniform field properties 300 coils were used to create uniform field properties (300 V/in., 0.3 mT). Separate and combined alternating electric and magnetic fields effects were studied at a combined field frequency of 60, 600, and 6000 Hz at room temperature. These fields did not elevate the temperature of the culture plates above room temperature. Petri dishes containing each tester strain in top agar were exposed to an electric field (E), magnetic field (M), combined electric and magnetic field (EM), or no additional field above ambient conditions in the lab (control). Four plates containing each strain were exposed in each condition: two plates had the appropriate positive-control mutagen for each strain included in the top agar and two plates did not. Plates were exposed to either E, M, EM, or control conditions at room temperature for 48 hr. and then incubated an additional 24 hr. at 37 deg. C. The plates containing mutagen in the top agar showed an increased number of colonies consistent with mutagenesis. However, the rate of mutation in the S. Typhimurium strains TA97a, TA98, TA100, and TA102 in either the presence or absence of mutagen was not affected by 48 hr. exposure at room temperature to E, M, or EM fields at 60, 600, 94 6000 Hz. 24 refs., 1 fig., 3 tabs.

Morandi, M.A.; Pak, C.M.; Caren, R.P.; Caren, L.D. [California State Univ., Northridge, CA (United States)] [California State Univ., Northridge, CA (United States)

1996-12-31

240

Absolute interferometric test of Fresnel zone plates  

Microsoft Academic Search

An absolute interferometric test of two-level binary Fresnel zone plates (FZPs) is presented. Five measurements with a wavefront testing interferometer are required to fully separate interferometer errors from those of the FZP. The method provides both errors, pattern errors and surface figure errors of the zone plate absolutely. The test method is suitable for zone mirrors and zone lenses. Test

S. Reichelt; R. Freimann; H. J. Tiziani

2001-01-01

241

Absolute instability of the Gaussian wake profile  

NASA Technical Reports Server (NTRS)

Linear parallel-flow stability theory has been used to investigate the effect of viscosity on the local absolute instability of a family of wake profiles with a Gaussian velocity distribution. The type of local instability, i.e., convective or absolute, is determined by the location of a branch-point singularity with zero group velocity of the complex dispersion relation for the instability waves. The effects of viscosity were found to be weak for values of the wake Reynolds number, based on the center-line velocity defect and the wake half-width, larger than about 400. Absolute instability occurs only for sufficiently large values of the center-line wake defect. The critical value of this parameter increases with decreasing wake Reynolds number, thereby indicating a shrinking region of absolute instability with decreasing wake Reynolds number. If backflow is not allowed, absolute instability does not occur for wake Reynolds numbers smaller than about 38.

Hultgren, Lennart S.; Aggarwal, Arun K.

1987-01-01

242

Survey of Personal Magnetic Field Exposure Phase I: Pilot Study and Design of Phase II, EMF Rapid Program, Engineering Project No. 6.  

National Technical Information Service (NTIS)

The 'Survey of Personal Magnetic Field Exposure' is one of several engineering research projects of the EMF Research and Public Information Dissemination (RAPID) Program. The objective of this project is to characterize personaI magnetic field exposure of...

1998-01-01

243

Using model organism Saccharomyces cerevisiae to evaluate the effects of ELF-MF and RF-EMF exposure on global gene expression.  

PubMed

The potential health hazard of exposure to electromagnetic fields (EMF) continues to cause public concern. However, the possibility of biological and health effects of exposure to EMF remains controversial and their biophysical mechanisms are unknown. In the present study, we used Saccharomyces cerevisiae to identify genes responding to extremely low frequency magnetic fields (ELF-MF) and to radiofrequency EMF (RF-EMF) exposures. The yeast cells were exposed for 6?h to either 0.4?mT 50?Hz ELF-MF or 1800?MHz RF-EMF at a specific absorption rate of 4.7?W/kg. Gene expression was analyzed by microarray screening and confirmed using real-time reverse transcription-polymerase chain reaction (RT-PCR). We were unable to confirm microarray-detected changes in three of the ELF-MF responsive candidate genes using RT-PCR (P?>?0.05). On the other hand, out of the 40 potential RF-EMF responsive genes, only the expressions of structural maintenance of chromosomes 3 (SMC3) and aquaporin 2 (AQY2 (m)) were confirmed, while three other genes, that is, halotolerance protein 9 (HAL9), yet another kinase 1 (YAK1) and one function-unknown gene (open reading frame: YJL171C), showed opposite changes in expression compared to the microarray data (P?EMF is limited to only a very small number of genes. The possible biological consequences of the gene expression changes induced by RF-EMF await further investigation. PMID:22487891

Chen, Guangdi; Lu, Deqiang; Chiang, Huai; Leszczynski, Dariusz; Xu, Zhengping

2012-10-01

244

Stability of a Cable Nicrosil-Nisil Thermocouple under Thermal Cycling  

NASA Astrophysics Data System (ADS)

Experimental data on the stability of cable Nicrosil-Nisil thermocouples (type N) under step-by-step thermal cycling in the temperature range 20 to 1100°C and also under long-term heating in air at the temperature 1085 +/- 10 °C are presented. The analysis of the influence of thermal cycling on thermal EMF drift is carried out. We conclude that N type thermocouples can be used as the reference thermocouple for the calibration of industrial base-metal thermocouples.

Belevtsev, A. V.; Karzhavin, A. V.; Ulanowsky, A. A.

2003-09-01

245

Absolute efficiency measurements with the 10B based Jalousie detector  

NASA Astrophysics Data System (ADS)

The 10B based Jalousie detector is a replacement for 3He counter tubes, which are nowadays less affordable for large area detectors due to the 3He crisis. In this paper we investigate and verify the performance of the new 10B based detector concept and its adoption for the POWTEX diffractometer, which is designed for the detection of thermal neutrons with predicted detection efficiencies of 75-50% for neutron energies of 10-100 meV, respectively. The predicted detection efficiency has been verified by absolute measurements using neutrons with a wavelength of 1.17 Å (59 meV).

Modzel, G.; Henske, M.; Houben, A.; Klein, M.; Köhli, M.; Lennert, P.; Meven, M.; Schmidt, C. J.; Schmidt, U.; Schweika, W.

2014-04-01

246

Phase transformations and thermodynamic behavior of the YBa2Cu3O(sub)x system via EMF measurements  

Microsoft Academic Search

EMF measurements of oxygen fugacities as a function of stoichiometry in YBa2Cu3Ox were made in the temperature range 650-750 C by means of an oxygen titration technique with a ZrO2 electrolyte doped with Y2O3. From plots of equilibrium oxygen pressures versus x, no sign of a change in curvature or discontinuity was observed at an oxygen stoichiometry of x =

M. Tetenbaum; A. Brown; M. Blander

1988-01-01

247

Analysis and Optimization of Back-EMF Waveform of a Novel Flux-Switching Permanent Magnet Motor  

Microsoft Academic Search

Flux-switching permanent magnet (FSPM) motor is a novel PM machine with doubly-salient structure, having magnets in the stator and employing concentrated stator windings, which attracts considerable interests due to its essentially sinusoidal phase back-EMF waveform. However, to date, this inherent nature of this outstanding feature is not investigated, and will be studied in this paper. A typical 3-phase FSPM motor

Wei Hua; Ming Cheng; Z. Q. Zhu; D. Howe

2007-01-01

248

An online identification method for both stator resistance and back-EMF coefficient of PMSMs without rotational transducers  

Microsoft Academic Search

This letter describes an effective online method for identifying both the stator resistance and the back-electromotive-force (EMF) coefficient of a permanent-magnet synchronous motor (PMSM) without rotational transducers. Using only the information of stator currents and voltages, it can provide fairly good identification accuracy under various load conditions and can be easily incorporated into most sensorless speed control schemes proposed in

Kyu-Wang Lee; Doo-Hee Jung; In-Joong Ha

2004-01-01

249

Platinum versus palladium thermocouples: an emf-temperature reference function for the range 0 °C to 1500 °C  

Microsoft Academic Search

We present an emf-temperature reference function for platinum versus palladium (Pt\\/Pd) thermocouples in air for the range 0 °C to 1500 °C. The reference function is based on the International Temperature Scale of 1990 (ITS-90) and has an expanded uncertainty (coverage factor of two) of less than the equivalent of 11 mK for temperatures up to 1050 °C and rising

G W Burns; D C Ripple; M Battuello

1998-01-01

250

Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in cultured mammalian cells are not independently reproducible  

Microsoft Academic Search

Conflicting results have been published regarding the induction of genotoxic effects by exposure to radiofrequency electromagnetic fields (RF-EMF). Using the comet assay, the micronucleus test and the chromosome aberration test with human fibroblasts (ES1 cells), the EU-funded “REFLEX” project (Risk Evaluation of Potential Environmental Hazards From Low Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods) reported clearly positive effects

Günter Speit; Petra Schütz; Heike Hoffmann

2007-01-01

251

Sensorless flux-weakening control of permanent magnet brushless machines using third-harmonic back-EMF  

Microsoft Academic Search

The sensorless control of brushless machines based on the detection of the third-harmonic back-EMF is relatively simple and potentially low-cost. However, it has been only reported for brushless DC operation and normal commutation. In this paper, the utility of the method for the sensorless control of both brushless DC and AC drives, including operation in the flux-weakening mode, is demonstrated.

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

2003-01-01

252

Intracellular Ca2+ Mobilization and Beta-hexosaminidase Release Are Not Influenced by 60 Hz-electromagnetic Fields (EMF) in RBL 2H3 Cells  

PubMed Central

The effects of extremely low frequency electromagnetic fields (EMF) on intracellular Ca2+ mobilization and cellular function in RBL 2H3 cells were investigated. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not produce any cytotoxic effects in RBL 2H3 cells. Melittin, ionomycin and thapsigargin each dose-dependently increased the intracellular Ca2+ concentration. The increase of intracellular Ca2+ induced by these three agents was not affected by exposure to EMF (60 Hz, 1 mT) for 4 or 16 h in RBL 2H3 cells. To investigate the effect of EMF on exocytosis, we measured beta-hexosaminidase release in RBL 2H3 cells. Basal release of beta-hexosaminidase was 12.3±2.3% in RBL 2H3 cells. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not affect the basal or 1 µM melittin-induced beta-hexosaminidase release in RBL 2H3 cells. This study suggests that exposure to EMF (60 Hz, 0.1 or 1 mT), which is the limit of occupational exposure, has no influence on intracellular Ca2+ mobilization and cellular function in RBL 2H3 cells.

Hwang, Yeon Hee; Song, Ho Sun; Kim, Hee Rae; Ko, Myoung Soo; Jeong, Jae Min; Kim, Yong Ho; Ryu, Jeong Soo; Sohn, Uy Dong; Gimm, Yoon-Myoung; Myung, Sung Ho

2011-01-01

253

The Simplicity Argument and Absolute Morality  

ERIC Educational Resources Information Center

In this paper the author has maintained that there is a similarity of thought to be found in the writings of Cudworth, Emerson, and Husserl in his investigation of an absolute system of morality. (Author/RK)

Mijuskovic, Ben

1975-01-01

254

The Parabola Test for Absolute Stability.  

National Technical Information Service (NTIS)

In applying the Popov stability test, a certain straight line is drawn; the Popov locus must lie on one side of this line. Thus geometric considerations alone indicate that the interesting sectors of absolute stability for conditionally stable systems can...

A. R. Bergen M. A. Sapiro

1967-01-01

255

A New Gimmick for Assigning Absolute Configuration.  

ERIC Educational Resources Information Center

A five-step procedure is provided to help students in making the assignment absolute configuration less bothersome. Examples for both single (2-butanol) and multi-chiral carbon (3-chloro-2-butanol) molecules are included. (JN)

Ayorinde, F. O.

1983-01-01

256

Magnifying absolute instruments for optically homogeneous regions  

SciTech Connect

We propose a class of magnifying absolute optical instruments with a positive isotropic refractive index. They create magnified stigmatic images, either virtual or real, of optically homogeneous three-dimensional spatial regions within geometrical optics.

Tyc, Tomas [Institute of Theoretical Physics and Astrophysics, Masaryk University, Kotlarska 2, CZ-61 137 Brno (Czech Republic)

2011-09-15

257

A note on exponential absolute stability.  

NASA Technical Reports Server (NTRS)

A new sufficient condition is formulated for the Lur'e type nonlinear continuous system to be exponentially absolutely stable. The condition relaxes the assumptions on the nonlinear characteristic by modifying the requirements on the linear part of the system.

Siljak, D. D.; Sun, C. K.

1972-01-01

258

A Method of Measuring Low Absolute Pressures.  

National Technical Information Service (NTIS)

The method of measuring low absolute pressures by using a single-capillary compression manometer differs in that, to increase accuracy and exclude random errors, mercury flows to the measuring capillary entrance and gradually rises in the capillary withou...

A. V. Eryukhin

1964-01-01

259

Removal of humic substances (HS) from water by electro-microfiltration (EMF).  

PubMed

Humic substances (HS) represent the common agents contributing to flux decline during membrane filtration of natural water. In order to minimize the fouling during microfiltration (MF) of HS, modifying the operation of MF presents a promising alternative. A laboratory-scale electro-microfiltration (EMF) module was used to separate Aldrich HS from water by applying a voltage across the membrane. The presence of an electric field significantly reduced the flux decline. A flux comparable to that of ion-free water was attained when the voltage was near the critical electric field strength (Ecritical), i.e., the electrical field gradient that balances the advective and electrophoretic velocities of solute. At an applied voltage of 100 V (approximately 110 V/cm), it was able to reduce UV absorbance at 254 nm (UV254), total organic carbon (TOC) and trihalomethane formation potential (THMFP) by over 50% in the permeate. Results from 1H nuclear magnetic resonance (1H NMR) analysis suggest that the aromatic and functionalized aliphatic fractions decreased significantly in the permeate. The charged HS have large molecule weight compared with those passing through membrane. Results clearly indicate that a combination of electric force with MF can increase HS rejection and decrease flux decline. Electrophoretic attraction was the major mechanism for the improvement of flux and rejection over time. PMID:16616771

Weng, Yu-Hsiang; Li, Kung-Cheh; Chaung-Hsieh, Lin Han; Huang, C P

2006-05-01

260

Extended EMF Observer for Sensorless Control over a Wide Range of Speeds  

NASA Astrophysics Data System (ADS)

This paper presents an observer-based position sensorless control method involving signal injection, which is appicable over a wide range of speeds. An extended electromotive force (EEMF) observer is suitable for salient-pole synchronous motors because the position information of EMF and saliency are considered. Signal injection is needed to make use of the position information of saliency at low speeds. However, observers consist of a low-pass filter. Therefore, the position information of saliency has not been used for the EEMF observer. In this study, a signal injection method that does not cause a torque ripple is applied to make effective use of the EEMF observer at low speeds. The signal frequency can be selected such that it lies within the bandwidth of the observer. In this paper, a position estimation method based on heterodyne detection and involving the use of an EEMF observer with a filter is proposed. The proposed technique makes it possible to extend the operating range of the EEMF observer to lower speeds. The validity of the proposed control method is confirmed by experiments.

Ohnuma, Takumi; Doki, Shinji; Okuma, Shigeru

261

Perturbative Transport studies of Turbulent EMFs in the Madison Dynamo Experiment  

NASA Astrophysics Data System (ADS)

Previous experiments on the MDE have demonstrated the need for a turbulent electromotive force to describe the dynamics of the magnetic field evolution. In these experiments a weak, DC external seed field---sharing the symmetry axis of the mean flow---was applied to a flowing sodium. Data modeling showed that the currents measured in the sodium could not be explained from the mean flow alone. However, the overall trend was not inconsistent with an enhanced resistivity (a beta effect). Two new experiments are underway to better characterize this turbulent EMF. First, time varying magnetic fields will be applied to perturbatively measure current transport. Second, an internal velocity probe is being developed to directly measure the correlation between magnetic and velocity fluctuations at a given location. This poster will present numerical models which study the degree to which a spatial variation in the resistivity can be determined from measured responses in a range of frequencies. A high current H-bridge amplifier has been constructed to apply 500 gauss, sinusoidal fields with frequencies up to 10 hz. The profile of the response will be measured by an internal array of 3D hall probes. This profile should provide a measure of the turbulent enhancement to resistivity, and the degree to which it is reduced by the presence of a mean magnetic field.

Kaplan, E. J.; Forest, C. B.; Kendrick, R. D.; Rasmus, A. M.; Taylor, N. Z.

2009-11-01

262

A Cryogenic Radiometer for Absolute Radiometric Measurements  

Microsoft Academic Search

The adoption in 1979 of a new definition of the candela, which permitted a detector-based approach to the realization of the unit, has emphasized the importance of high-accuracy absolute radiation detectors. This paper describes a new electrical-substitution absolute radiometer operating at 5 K, based on a standard commercial helium cryostat, which has been developed at NPL for optical radiant-power measurements.

J E Martin; N P Fox; P J Key

1985-01-01

263

The absolute magnitudes of Type IA supernovae  

Microsoft Academic Search

Absolute magnitudes in the B, V, and I bands are derived for nine well-observed Type Ia supernovae, using host galaxy distances estimated via the surface brightness fluctuations or Tully-Fisher methods. These data indicate that there is a significant intrinsic dispersion in the absolute magnitudes at maximum light of Type Ia supernovae, amounting to +\\/- 0.8 mag in B, +\\/- 0.6

M. M. Phillips

1993-01-01

264

Absolute Temperature Monitoring Using RF Radiometry in the MRI Scanner  

PubMed Central

Temperature detection using microwave radiometry has proven value for noninvasively measuring the absolute temperature of tissues inside the body. However, current clinical radiometers operate in the gigahertz range, which limits their depth of penetration. We have designed and built a noninvasive radiometer which operates at radio frequencies (64 MHz) with ?100-kHz bandwidth, using an external RF loop coil as a thermal detector. The core of the radiometer is an accurate impedance measurement and automatic matching circuit of 0.05 ? accuracy to compensate for any load variations. The radiometer permits temperature measurements with accuracy of ±0.1°K, over a tested physiological range of 28° C–40° C in saline phantoms whose electric properties match those of tissue. Because 1.5 T magnetic resonance imaging (MRI) scanners also operate at 64 MHz, we demonstrate the feasibility of integrating our radiometer with an MRI scanner to monitor RF power deposition and temperature dosimetry, obtaining coarse, spatially resolved, absolute thermal maps in the physiological range. We conclude that RF radiometry offers promise as a direct, noninvasive method of monitoring tissue heating during MRI studies and thereby providing an independent means of verifying patient-safe operation. Other potential applications include titration of hyper- and hypo-therapies.

El-Sharkawy, AbdEl-Monem M.; Sotiriadis, Paul P.; Bottomley, Paul A.; Atalar, Ergin

2007-01-01

265

20 CFR 404.1205 - Absolute coverage groups.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Absolute coverage groups. 404.1205 Section 404.1205 ...Employees of State and Local Governments What Groups of Employees May Be Covered § 404.1205 Absolute coverage groups. (a) General. An absolute...

2013-04-01

266

An electromagnetic thermotherapy system with a deep penetration depth for percutaneous thermal ablation.  

PubMed

Thermal ablation has been a promising method to remove the cancerous tissues. Electromagnetic-based thermotherapy has been extensively investigated for a variety of medical applications recently. In this study, a prototype electromagnetic thermotherapy system has been developed with a new coil design and a two-section needle. The coil can generate an alternating electromagnetic field (EMF) with a deep penetration depth to remotely heat the needle which is located up to 15 cm away, enabling percutaneous thermal ablation. Several important parameters, including the heating effects of the needle at different positions, the intensity of the EMF and the induced temperature distribution on the surrounding tissue, are first explored. An in vitro animal experiment has also been performed which shows EMF-induced ablation in a porcine liver by the needle. Furthermore, an in vivo experiment on an animal model (a New Zealand white rabbit) is also conducted in the study. Thus, the two-section needle combined with the coil-generated EMF has been demonstrated to be a promising thermotherapy system for percutaneous thermal ablation. PMID:23990331

Huang, Sheng-Chieh; Chang, Yi-Yuan; Kang, Jui-Wen; Tsai, Hung-Wen; Shan, Yan-Shen; Lin, Xi-Zhang; Lee, Gwo-Bin

2014-01-01

267

Sky-Scanning Radiometer for Absolute Measurements of Atmospheric Long-Wave Radiation  

NASA Astrophysics Data System (ADS)

Atmospheric long-wave radiation is one of the most promising parameters for observations of climate change that are greenhouse effect related. Long-wave irradiance is usually measured with pyrgeometers that consist of a flat thermopile and a hemispherical dome acting as a filter and protecting the absorbing receiver surface. Pyrgeometers are blackbody calibrated, but uncertainties, mainly related to the silicon hemisphere, arise from thermal effects, inadequate spectral transmission, and cosine-response errors. The new absolute sky-scanning radiometer (ASR) allows absolute measurements of atmospheric long-wave radiation and is suggested as a future reference standard for pyrgeometer field calibration. The calibration of the ASR is based on a reference blackbody source traced to absolute temperature standards. The pyroelectric detector has no window to prevent thermal and spectral transmission effects. Scanning the sky with a narrow viewing angle and integrating with the Gaussian quadrature, rather than taking hemispherical measurements, prevent errors related to the cosine effect.

Philipona, Rolf

2001-05-01

268

New absolute magnitude calibrations for detached binaries  

NASA Astrophysics Data System (ADS)

Lutz-Kelker bias corrected absolute magnitude calibrations for the detached binary systems with main-sequence components are presented. The absolute magnitudes of the calibrator stars were derived at intrinsic colours of Johnson-Cousins and 2MASS (Two Micron All Sky Survey) photometric systems. As for the calibrator stars, 44 detached binaries were selected from the Hipparcos catalogue, which have relative observed parallax errors smaller than 15% (??/??0.15). The calibration equations which provide the corrected absolute magnitude for optical and near-infrared pass bands are valid for wide ranges of colours and absolute magnitudes: -0.18<(B-V)0<0.91, -1.6absolute magnitude calibrations of this study can be used as a convenient statistical tool to estimate the true distances of detached binaries out of Hipparcos' distance limit.

Bilir, S.; Ak, T.; Soydugan, E.; Soydugan, F.; Yaz, E.; Filiz Ak, N.; Eker, Z.; Demircan, O.; Helvaci, M.

2008-10-01

269

Absolute magnitude calibration for red clump stars  

NASA Astrophysics Data System (ADS)

We combined the ( K s , J- K s ) data in Laney et al. (Mon. Not. R. Astron. Soc. 419:1637, 2012) with the V apparent magnitudes and trigonometric parallaxes taken from the Hipparcos catalogue and used them to fit the M_{Ks} absolute magnitude to a linear polynomial in terms of V- K s colour. The mean and standard deviation of the absolute magnitude residuals, -0.001 and 0.195 mag, respectively, estimated for 224 red clump stars in Laney et al. (2012) are (absolutely) smaller than the corresponding ones estimated by the procedure which adopts a mean M_{Ks}=-1.613 {mag} absolute magnitude for all red clump stars, -0.053 and 0.218 mag, respectively. The statistics estimated by applying the linear equation to the data of 282 red clump stars in Alves (Astrophys. J. 539:732, 2000) are larger, ? M_{Ks}=0.209 and ?=0.524 mag, which can be explained by a different absolute magnitude trend, i.e. condensation along a horizontal distribution.

Karaali, S.; Bilir, S.; Yaz Gökçe, E.

2013-07-01

270

Absolute isotopic abundances of TI in meteorites  

NASA Astrophysics Data System (ADS)

The absolute isotope abundance of Ti has been determined in Ca-Al-rich inclusions from the Allende and Leoville meteorites and in samples of whole meteorites. The absolute Ti isotope abundances differ by a significant mass dependent isotope fractionation transformation from the previously reported abundances, which were normalized for fractionation using 46Ti/48Ti. Therefore, the absolute compositions define distinct nucleosynthetic components from those previously identified or reflect the existence of significant mass dependent isotope fractionation in nature. The authors provide a general formalism for determining the possible isotope compositions of the exotic Ti from the measured composition, for different values of isotope fractionation in nature and for different mixing ratios of the exotic and normal components.

Niederer, F. R.; Papanastassiou, D. A.; Wasserburg, G. J.

1985-03-01

271

Absolute Photoacoustic Thermometry in Deep Tissue  

PubMed Central

Photoacoustic (PA) thermography is a promising tool for temperature measurement in deep tissue. Here, we propose an absolute temperature measurement method based on the dual temperature dependences of the Grüneisen parameter and the speed of sound in tissue. By taking ratiometric measurements at two adjacent temperatures, we can eliminate the factors that are temperature irrelevant but difficult to correct for in deep tissue. To validate our method, absolute temperatures of blood-filled tubes embedded ~9 mm deep in chicken tissue were measured in a biologically relevant range from 28 °C to 46 °C. The temperature measurement accuracy was ~0.6 °C. The results suggest that our method can be potentially used for absolute temperature monitoring in deep tissue during thermotherapy.

Tai, Stephen; Zhou, Yong; Wang, Lihong V.

2013-01-01

272

Absolute photoacoustic thermometry in deep tissue.  

PubMed

Photoacoustic thermography is a promising tool for temperature measurement in deep tissue. Here we propose an absolute temperature measurement method based on the dual temperature dependences of the Grüneisen parameter and the speed of sound in tissue. By taking ratiometric measurements at two adjacent temperatures, we can eliminate the factors that are temperature irrelevant but difficult to correct for in deep tissue. To validate our method, absolute temperatures of blood-filled tubes embedded ~9 mm deep in chicken tissue were measured in a biologically relevant range from 28°C to 46°C. The temperature measurement accuracy was ~0.6°C. The results suggest that our method can be potentially used for absolute temperature monitoring in deep tissue during thermotherapy. PMID:24322224

Yao, Junjie; Ke, Haixin; Tai, Stephen; Zhou, Yong; Wang, Lihong V

2013-12-15

273

Absolute Zero: Community Education Outreach Guide  

NSDL National Science Digital Library

This guide provides curricular resources for study of the history and science of the quest for ever colder temperature. Designed for teachers and informal educators of middle school students. this guide offers hands-on demonstrations, questions to encourage student participation, suggestions for class activities, and ways to encourage students to continue studying the science. Topics include low-temperature physics and the impact of technologies such as air conditioning, refrigeration and liquefied gases. This material is related to a two-part public broadcasting special, Absolute Zero, produced by Meridian Productions and Windfall Films. Absolute Zero is underwritten by the National Science Foundation and the Alfred P. Sloan Foundation and is based largely on Tom Shachtmanâs acclaimed book, Absolute Zero and the Conquest of Cold.

2008-09-18

274

Absolute calibration in vivo measurement systems  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. Absolute calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The absolute calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs.

Kruchten, D.A.; Hickman, D.P.

1991-02-01

275

Quantitative standards for absolute linguistic universals.  

PubMed

Absolute linguistic universals are often justified by cross-linguistic analysis: If all observed languages exhibit a property, the property is taken to be a likely universal, perhaps specified in the cognitive or linguistic systems of language learners and users. In many cases, these patterns are then taken to motivate linguistic theory. Here, we show that cross-linguistic analysis will very rarely be able to statistically justify absolute, inviolable patterns in language. We formalize two statistical methods-frequentist and Bayesian-and show that in both it is possible to find strict linguistic universals, but that the numbers of independent languages necessary to do so is generally unachievable. This suggests that methods other than typological statistics are necessary to establish absolute properties of human language, and thus that many of the purported universals in linguistics have not received sufficient empirical justification. PMID:24117660

Piantadosi, Steven T; Gibson, Edward

2014-05-01

276

Absolute Continuity in Noncommutative Measure Theory  

NASA Astrophysics Data System (ADS)

Recent results on absolute continuity of Banach space valued operators and convergence theorems on operator algebras are deepened and summarized. It is shown that absolute continuity of an operator T on a von Neumann algebra M with respect to a positive normal functional ? on M is not implied by the fact that the null projections of ? are the null projections of T. However, it is proved that the implication above is true whenever M is finite or T is weak*-continuous. Further it is shown that the absolute value preserves the Vitali-Hahn-Saks property if, and only if, the underlying algebra is finite. This result improves classical results on weak compactness of sets of noncommutative measures.

Hamhalter, Jan

2010-12-01

277

First-Principles Calculations of Absolute Concentrations and Self-Diffusion Constants of Vacancies in Lithium  

Microsoft Academic Search

For lithium the absolute concentrations of thermal monovacancies and the self-diffusion constants via vacancies are calculated ab initio using the local-density approximation in combination with the transition-state theory of diffusion. The diffusion data are in good agreement with experimental data for high temperatures.

W. Frank; U. Breier; C. Elsässer; M. Fähnle

1996-01-01

278

The amelioration of phagocytic ability in microglial cells by curcumin through the inhibition of EMF-induced pro-inflammatory responses  

PubMed Central

Background Insufficient clearance by microglial cells, prevalent in several neurological conditions and diseases, is intricately intertwined with MFG-E8 expression and inflammatory responses. Electromagnetic field (EMF) exposure can elicit the pro-inflammatory activation and may also trigger an alteration of the clearance function in microglial cells. Curcumin has important roles in the anti-inflammatory and phagocytic process. Here, we evaluated the ability of curcumin to ameliorate the phagocytic ability of EMF-exposed microglial cells (N9 cells) and documented relative pathways. Methods N9 cells were pretreated with or without recombinant murine MFG-E8 (rmMFG-E8), curcumin and an antibody of toll-like receptor 4 (anti-TLR4), and subsequently treated with EMF or a sham exposure. Their phagocytic ability was evaluated using phosphatidylserine-containing fluorescent bioparticles. The pro-inflammatory activation of microglia was assessed via CD11b immunoreactivity and the production of tumor necrosis factor-? (TNF-?), interleukin-6 (IL-6), interleukin-1? (IL-1?) and nitric oxide (NO) via the enzyme-linked immunosorbent assay or the Griess test. We evaluated the ability of curcumin to ameliorate the phagocytic ability of EMF-exposed N9 cells, including checking the expression of MFG-E8, ?v?3 integrin, TLR4, nuclear factor-?B (NF-?B) and signal transducer and activator of transcription 3 (STAT3) using Western blotting. Results EMF exposure dramatically enhanced the expression of CD11b and depressed the phagocytic ability of N9 cells. rmMFG-E8 could clearly ameliorate the phagocytic ability of N9 cells after EMF exposure. We also found that EMF exposure significantly increased the secretion of pro-inflammatory cytokines (TNF-?, IL-6 and IL-1?) and the production of NO; however, these increases were efficiently chilled by the addition of curcumin to the culture medium. This reduction led to the amelioration of the phagocytic ability of EMF-exposed N9 cells. Western blot analysis revealed that curcumin and naloxone restored the expression of MFG-E8 but had no effect on TLR4 and cytosolic STAT3. Moreover, curcumin significantly reduced the expression of NF-?B p65 in nuclei and phospho-STAT3 (p-STAT3) in cytosols and nuclei. Conclusions This study indicates that curcumin ameliorates the depressed MFG-E8 expression and the attenuated phagocytic ability of EMF-exposed N9 cells, which is attributable to the inhibition of the pro-inflammatory response through the NF-?B and STAT3 pathways.

2014-01-01

279

Absolute Distance Measurement with the MSTAR Sensor  

NASA Technical Reports Server (NTRS)

The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

2003-01-01

280

[Dependence of the non-thermal radiofrequency electromagnetic field bioeffects on the typological features of electroencephalogram in humans].  

PubMed

In researches with participation of volunteers bioeffects of short-term non-thermal radiofrequency electromagnetic field (RF EMF) exposure were studied. The basic form of brain's reaction was the amplification of energy in a-range in electroencephalogram (EEG) spectra. Dependence of these changes, not only due to the changes of the exposure parameters, but also due to personal EEG typological features was shown. Moderate degree of the alpha frequencies domination in the background promoted development of reaction of a brain to the RF EMF exposure. To a lesser degree it was shown at hyperactivity of this range and, practically, was absent in the conditions of theta- or beta2-range domination in the EEG background with the open and closed eyes. The combination of RF EMF exposure and monotonous activity has authentically strengthened result, keeping the basic form of reaction (energy amplification in the alpha range of EEG spectrum) and dependence on EEG typological features. PMID:21434398

Luk'ianova, S N; Grigor'ev, Iu G; Grigor'ev, O A; Merkulov, A V

2010-01-01

281

Effects of time-variant extremely low-frequency (ELF) electromagnetic fields (EMF) on cholinesterase activity in Dictyostelium discoideum (Protista).  

PubMed

Recently, we detected propionylcholinesterase (PrChE) activity in single-cell amoebae of Dictyostelium discoideum using cytochemical, electrophoretic, and spectrophotometric methods. The involvement of this enzyme activity in cell-cell and cell-environment interactions was suggested. In this work, we found that exposure of single-cell amoebae to an extremely low-frequency electromagnetic fields (ELF-EMF) of 300 microT, 50 Hz, from 1 h up to 48 h at 21 +/- 1 degrees C affected PrChE activity. PMID:16425446

Amaroli, Andrea; Trielli, Francesca; Bianco, Bruno; Giordano, Stefano; Moggia, Elsa; Corrado, Maria U Delmonte

2005-12-15

282

Investigation of the interaction of HCl and three amino acids, HEPES, MOPSO and glycine, by EMF measurements  

Microsoft Academic Search

Ionic interaction in the three systems Hcl-HEPES (N-2-hydroxyethylpiperazine-N?-2-ethanesulfonic acid), HCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic\\u000a acid), and HCl-glycine have been studied in terms of their mutual influence on the respective activity coefficients of each\\u000a component. Activity coefficients for each component of the three systems are calculated from emf measurements of solutions\\u000a containing HCl and the amino acid in a H2\\/solution\\/AgCl,Ag cell at 25°C. The

Daming Feng; W. F. Koch; Y. C. Wu

1992-01-01

283

A next-generation EMF simulator for EUV lithography based on the pseudo-spectral time-domain method  

NASA Astrophysics Data System (ADS)

The FDTD method has difficulty in modeling buried defects in multilayered EUV masks because of the limitations of grid snapping, large numerical-dispersion errors and rectangular cells that do not fit the non-planar shapes of buried defects easily. In this paper, a rigorous EMF simulator based on the pseudo-spectral time-domain (PSTD) method is discussed. The PSTD method is free from the limitations of FDTD and can model buried defects in EUV masks accurately. Detailed comparison with FDTD is given to demonstrate the accuracy, speed and memory efficiency of PSTD for the rigorous simulation of buried defects in EUV masks.

Yeung, Michael S.

2012-03-01

284

Absolute rate theories of epigenetic stability  

Microsoft Academic Search

Spontaneous switching events in most characterized genetic switches are rare, resulting in extremely stable epigenetic properties. We show how simple arguments lead to theories of the rate of such events much like the absolute rate theory of chemical reactions corrected by a transmission factor. Both the probability of the rare cellular states that allow epigenetic escape and the transmission factor

Aleksandra M. Walczak; José N. Onuchic; Peter G. Wolynes

2005-01-01

285

Absolute Measurement of exp 152 Eu.  

National Technical Information Service (NTIS)

A new method of the absolute measurement for exp 152 Eu was established based on the 4 pi beta - gamma spectroscopic anti-coincidence method. It is a coincidence counting method consisting of a 4 pi beta -counter and a Ge(Li) gamma -ray detector, in which...

H. Baba S. Baba S. Ichikawa T. Sekine I. Ishikawa

1981-01-01

286

Absolute versus relative time in process algebras  

Microsoft Academic Search

Timed process algebras are useful tools for the specification and verification of real time systems. We study the relationships between two of these algebras, cIpa ('Closed Interval Process Algebra') and TCCS ('Temporal CCS') which deal with temporal aspects of concurrent systems by following very different interpretations: durational actions versus durationless actions, absolute time versus relative time, timed functional behavior versus

Flavio Corradini

1997-01-01

287

Absolute versus Relative Time in Process Algebras  

Microsoft Academic Search

Timed process algebras are useful tools for the specification and verification of real-time systems. We study the relationships between two of these algebras, cIpa (closed interval process Algebra) and TCCS (temporal CCS), which deal with temporal aspects of concurrent systems by following very different interpretations: durational actions versus durationless actions, absolute time versus relative time, timed functional behavior versus time

Flavio Corradini

2000-01-01

288

Teaching Absolute Value Inequalities to Mature Students  

ERIC Educational Resources Information Center

This paper gives an account of a teaching experiment on absolute value inequalities, whose aim was to identify characteristics of an approach that would realize the potential of the topic to develop theoretical thinking in students enrolled in prerequisite mathematics courses at a large, urban North American university. The potential is…

Sierpinska, Anna; Bobos, Georgeana; Pruncut, Andreea

2011-01-01

289

Absolute Points for Multiple Assignment Problems  

ERIC Educational Resources Information Center

An algorithm is presented to solve multiple assignment problems in which a cost is incurred only when an assignment is made at a given cell. The proposed method recursively searches for single/group absolute points to identify cells that must be loaded in any optimal solution. Unlike other methods, the first solution is the optimal solution. The…

Adlakha, V.; Kowalski, K.

2006-01-01

290

Precision absolute positional measurement of laser beams.  

PubMed

We describe an instrument which, coupled with a suitable coordinate measuring machine, facilitates the absolute measurement within the machine frame of the propagation direction of a millimeter-scale laser beam to an accuracy of around ±4 ?m in position and ±20 ?rad in angle. PMID:23669658

Fitzsimons, Ewan D; Bogenstahl, Johanna; Hough, James; Killow, Christian J; Perreur-Lloyd, Michael; Robertson, David I; Ward, Henry

2013-04-20

291

Resonance absolute quantum reflection at selected energies.  

PubMed

We present one-dimensional local potentials with an absolute reflection at a given energy value which can be above barriers. The corresponding energy dependence of a reflection coefficient exhibits resonance behavior. The inversion technique provides the potentials with specified widths of reflection resonances, their number and positions. The multichannel systems (exact models) with a complete reflection are also given. PMID:11690195

Chabanov, V M; Zakhariev, B N

2001-10-15

292

Absolutely Uniform Illumination of Laser Fusion Pellets.  

National Technical Information Service (NTIS)

Absolutely uniform illumination of spherical laser fusion pellets is possible when the energy deposition from a single laser beam is given by a simple cos 3 theta distribution. Conditions can be derived for which the laser beam targeting angles allow this...

A. J. Schmitt

1984-01-01

293

An Absolute Electrometer for the Physics Laboratory  

ERIC Educational Resources Information Center

A low-cost, easy-to-use absolute electrometer is presented: two thin metallic plates and an electronic balance, usually available in a laboratory, are used. We report on the very good performance of the device that allows precise measurements of the force acting between two charged plates. (Contains 5 footnotes, 2 tables, and 6 figures.)

Straulino, S.; Cartacci, A.

2009-01-01

294

Safety of high speed guided ground transportation systems: Review of existing EMF guidelines, standards and regulations. Final report, January-June 1993  

SciTech Connect

Although there are no maglev or other advanced high-speed rail systems currently operating in the United States, EMF exposure is still of concern as it relates top 60 hertz (Hz) power transmission and distribution lines and electrical appliances. The report provides information on existing and proposed EMF guidelines, standards and regulations at the international, national, state, and local levels. It covers fields in the frequency range of 0-100 Ghz and includes EMF exposures for both the general public and workers. Whereas the above frequency range includes radio frequencies and microwave frequencies, the main focus for the United States is on extremely low frequencies (ELF), such as those associated with the use of electric power. However, there is some discussion of regulation of higher frequency ranges in other countries.

Goellner, D.; Wilson, B.; Reiter, R.; Pilla, A.; Hankin, N.

1993-08-01

295

Interaction of DL-threonine with NaCl and NaNO 3in aqueous solutions: e.m.f. measurements with ion-selective electrodes  

Microsoft Academic Search

The interactions betweenDL-threonine and NaCl or NaNO3, atT=(298.15±0.02) K, have been investigated by measuring e.m.f. values, with ion-selective electrodes (ISE), in electrochemical cells. The electrochemical cell employed consisted of two ion-selective electrodes, a cation and an anion ion-selective electrode, against a double junction reference electrode. The e.m.f. values thus obtained were used to calculate the activity coefficients ofDL-threonine in aqueous

Ana M. Soto-Campos; Mohammad K. Khoshkbarchi; Juan H. Vera

1997-01-01

296

Problem of Talbot self-images localization: adaptive photo-EMF-based detector vs. CCD-based methods  

NASA Astrophysics Data System (ADS)

Talbot self-images localization is important in many optical applications such as interferometry, metrology and nanolithography. Usually, the problem of self-images localization is reduced to the finding the planes of maximal light pattern visibility. There are several conventional techniques that determine the contrast of an intensity distribution generated by a periodical object, such as root mean square (RMS) method, and variogram-based method. In all these cases, a CCD camera is used to record the light patterns that are processed and analyzed in order to find the self-image position. Recently, it has been proposed the use an adaptive photo-detector based on the non-steadystate photo-electromotive force (photo-EMF) effect, which uses periodically oscillating light pattern to induce alternating current through the short-circuited photoconductive sample. Here we perform the theoretical analysis of the technique based on the photo-EMF effect against the conventional methods for the localization of the Talbot patterns.

Guízar-Iturbide, Ileana; de La Fraga, Luis Gerardo; Rodríguez-Montero, Ponciano; Mansurova, Svetlana

2010-06-01

297

Standard molar Gibbs free energy of formation of PbO(s) over a wide temperature range from EMF measurements  

NASA Astrophysics Data System (ADS)

The EMF of the following galvanic cells, Kanthal, Re, Pb, PbO? CSZ? O2 (1 atm.), PtKanthal, Re, Pb, PbO? CSZ? O2(1 atm.), RuO2, Ptwere measured as a function of temperature. With O 2 (1 atm.), RuO 2 as the reference electrode, measurements were possible at low temperatures close to the melting point of Pb. Standard Gibbs energy of formation, ? fG0m was calculated from the emf measurements made over a wide range of temperature (612-1111 K) and is given by the expression: ?fG 0m< ?-PbO>±0.10 kJ=-218.98+0.09963T . A third law treatment of the data yielded a value of -218.08 ± 0.07 kJ mol -1 for the enthalpy of formation of PbO(s) at 298.15 K, ? fH0m which is in excellent agreement with second law estimate of -218.07 ± 0.07 kJ mol -1.

Ganesan, Rajesh; Gnanasekaran, T.; Srinivasa, Raman S.

2003-08-01

298

Rigorous EMF simulation of the impact of photomask line-edge and line-width roughness on lithographic processes  

NASA Astrophysics Data System (ADS)

The impact of edge profile roughness of the absorber lines on an optical photomask has been studied by means of rigorous EMF simulation for the mask diffraction spectrum and subsequent imaging. Roughness has been modeled using two different approaches, a sinusoidal description and an algorithm known from literature based on Fourier transformation. The latter one allows one to arbitrarily create rough profiles and surfaces based on the three morphological parameters standard deviation ?, roughness exponent ?, and correlation length ?. A software interface for use of the generated profiles with the waveguide EMF solver of the Dr.LiTHO lithography simulation suite has been implemented. It was shown by means of image analysis and study of the resulting process windows that mask roughness is partially transferred to the aerial image. Isolated and dense features behave differently, leading i.a. to an iso-dense bias different to that of ideal lines. Process windows shift or even shrink in the presence of roughness, due to a certain smearing of the curves reducing the overall window. Tapered sidewalls can add to these effects in the same order of magnitude.

Rudolph, Oliver H.; Evanschitzky, Peter; Erdmann, Andreas; Bär, Eberhard; Lorenz, Jürgen

2011-10-01

299

Growth from a hypercooled melt near absolute stability  

NASA Technical Reports Server (NTRS)

The stability of a solid-liquid interface in a hypercooled melt is studied, taking into account attachment kinetics, surface energy, and surface energy in the heat balance. There is a basic-state solution with the planar interface moving at constant speed. Linear-stability theory gives a long-wave absolute-stability limit. Near this point a string model is introduced in which a thermal-boundary-layer approximation is used and an evolution equation for the interface is obtained. In a limiting case this interface equation reduces to a Kuromoto-Sivashinsky equation. Comparison with experimental and numerical results are discussed, and a conceptual picture of unconstrained growth for all undercoolings is addressed.

Umantsev, A.; Davis, S. H.

1992-01-01

300

Absolute Total Scattering Cross Section of He-H2 over the Relative Velocity Range of 2000 to 3000 m/sec.  

National Technical Information Service (NTIS)

Absolute helium-hydrogen molecule total cross sections for thermal energy collisions were measured using molecular beams derived from nozzle sources and crossed at right angles. The absolute density of the target gas (H2) was measured with a capacitance m...

J. G. Skofronick R. S. Grace

1971-01-01

301

Absolute and relative dosimetry for ELIMED  

SciTech Connect

The definition of detectors, methods and procedures for the absolute and relative dosimetry of laser-driven proton beams is a crucial step toward the clinical use of this new kind of beams. Hence, one of the ELIMED task, will be the definition of procedures aiming to obtain an absolute dose measure at the end of the transport beamline with an accuracy as close as possible to the one required for clinical applications (i.e. of the order of 5% or less). Relative dosimetry procedures must be established, as well: they are necessary in order to determine and verify the beam dose distributions and to monitor the beam fluence and the energetic spectra during irradiations. Radiochromic films, CR39, Faraday Cup, Secondary Emission Monitor (SEM) and transmission ionization chamber will be considered, designed and studied in order to perform a fully dosimetric characterization of the ELIMED proton beam.

Cirrone, G. A. P.; Schillaci, F.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Institute of Physics Czech Academy of Science, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic)] [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Institute of Physics Czech Academy of Science, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Cuttone, G.; Candiano, G.; Musumarra, A.; Pisciotta, P.; Romano, F. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy)] [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Carpinelli, M. [INFN Sezione di Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, Cagliari (Italy)] [INFN Sezione di Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, Cagliari (Italy); Leonora, E.; Randazzo, N. [INFN-Sezione di Catania, Via Santa Sofia 64, Catania (Italy)] [INFN-Sezione di Catania, Via Santa Sofia 64, Catania (Italy); Presti, D. Lo [INFN-Sezione di Catania, Via Santa Sofia 64, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy)] [INFN-Sezione di Catania, Via Santa Sofia 64, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Raffaele, L. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and INFN-Sezione di Catania, Via Santa Sofia 64, Catania (Italy)] [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and INFN-Sezione di Catania, Via Santa Sofia 64, Catania (Italy); Tramontana, A. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy)] [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Cirio, R.; Sacchi, R.; Monaco, V. [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino, Italy and Università di Torino, Dipartimento di Fisica, Via P.Giuria, 1 10125 Torino (Italy)] [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino, Italy and Università di Torino, Dipartimento di Fisica, Via P.Giuria, 1 10125 Torino (Italy); Marchetto, F.; Giordanengo, S. [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino (Italy)] [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino (Italy)

2013-07-26

302

Absolute effective areas of the HETGS  

NASA Astrophysics Data System (ADS)

XRCF measurements of the flight AXAF High Energy Transmission Grating Spectrometer throughput were used to determine absolute effective areas. The result are compared with component models of the HRMA, HETG and the ACIS-S. The comparison provides an independent view on HETG efficiencies as well as the detector efficiencies along the dispersion direction. Using the XRCF double crystal monochromator measurements in the range from 0.9 to 8.7 keV, the effective areas in the 1st order MEG were determined with an accuracy of better than 10 percent, in the 1st order HEG better than 15 percent throughout most of the energy range. This is within the goal set for the XRCF measurements to refine state of the art composite component model predictions, which in the future will allow us to draw conclusions on the in-flight HETGS absolute effective area.

Schulz, Norbert S.; Dewey, Daniel; Marshall, Herman L.

1998-11-01

303

Absolute plate motions by boundary velocity minimizations  

NASA Technical Reports Server (NTRS)

The main interaction of the earth's interior with the lithosphere is as a material source and sink. An absolute reference frame defined by minimizing the translational motion of tectonic plate boundaries differs by 0.6 cm/year from a frame defined by hot spot traces and by 0.4 cm/year from the frame defined by the most plausible model of drag forces on the plates. The rms absolute translational velocities are about 2 cm/year for ocean-ocean plate boundaries and 1.5 cm/year for ocean-continent plate boundaries. The close agreement between the source and sink and the drag-dependent definitions suggests that the lithosphere, as a stress guide, to some extent controls the locations of its sources and sinks.

Kaula, W. M.

1975-01-01

304

Absolute Proper Motions Outside the Plane (APOP)  

NASA Astrophysics Data System (ADS)

Most of the discovered exoplanets are close to our sun. Usually their host star is with large proper motions, which is an important parameter for exoplanet searching. The first version of absolute proper motions catalog achieved based on Digitized Sky Survey Schmidt plate where outside the galactic plane |b|>=27° is presented, resulting in a zero point error less than +/- 0.3 mas/yr, and the overall accuracy better than +/- 4.5 mas/yr for objects brighter than R F =18.5, and ranging from 4.5 to 9.0 mas/yr for objects with magnitude 18.5absolute proper motions related to the position, magnitude and color are practically all removed. The sky cover of this catalog is 22,525 degree 2, the mean density is 6444 objects/degree 2 and the magnitude limit is around R F =20.5.

Qi, Zhaoxiang; Yu, Yong; Smart, Richard L.; Lattanzi, Mario G.; Tang, Zhenghong; Bucciarelli, Beatrice; Vecchiato, Alberto; Spagna, Alessandro; McLean, Brian J.

2014-04-01

305

Absolute-magnitude Distributions of Supernovae  

NASA Astrophysics Data System (ADS)

The absolute-magnitude distributions of seven supernova (SN) types are presented. The data used here were primarily taken from the Asiago Supernova Catalogue, but were supplemented with additional data. We accounted for both foreground and host-galaxy extinction. A bootstrap method is used to correct the samples for Malmquist bias. Separately, we generate volume-limited samples, restricted to events within 100 Mpc. We find that the superluminous events (MB < -21) make up only about 0.1% of all SNe in the bias-corrected sample. The subluminous events (MB > -15) make up about 3%. The normal Ia distribution was the brightest with a mean absolute blue magnitude of -19.25. The IIP distribution was the dimmest at -16.75.

Richardson, Dean; Jenkins, Robert L., III; Wright, John; Maddox, Larry

2014-05-01

306

Dynamo action by turbulence in absolute equilibrium  

NASA Astrophysics Data System (ADS)

We consider the generation of a large-scale magnetic field by a turbulent flow driven by a small-scale helical forcing in a low magnetic Prandtl number fluid. We provide an estimate of the dynamo threshold that takes into account the presence of large-scale turbulent fluctuations by considering that the scales of the flow that mostly contribute to the dynamo process are roughly in absolute equilibrium. We show that turbulent flows in absolute equilibrium do generate dynamos and we compare their growth rates to their laminar counterparts. Finally, we show that the back reaction of the growing magnetic field modifies the statistical properties of turbulent flow by suppressing its kinetic helicity at large magnetic Reynolds number.

Gopalakrishnan Ganga Prasath, Srinivasa; Fauve, Stéphan; Brachet, Marc

2014-04-01

307

An absolute measure for a key currency  

NASA Astrophysics Data System (ADS)

It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

308

From Hubble's NGSL to Absolute Fluxes  

NASA Technical Reports Server (NTRS)

Hubble's Next Generation Spectral Library (NGSL) consists of R-l000 spectra of 374 stars of assorted temperature, gravity, and metallicity. Each spectrum covers the wavelength range, 0.18-1.00 microns. The library can be viewed and/or downloaded from the website, http://archive.stsci.edu/prepds/stisngsll. Stars in the NGSL are now being used as absolute flux standards at ground-based observatories. However, the uncertainty in the absolute flux is about 2%, which does not meet the requirements of dark-energy surveys. We are therefore developing an observing procedure that should yield fluxes with uncertainties less than 1 % and will take part in an HST proposal to observe up to 15 stars using this new procedure.

Heap, Sara R.; Lindler, Don

2012-01-01

309

Absolute orientation of molecules at interfaces.  

PubMed

A method to determine the absolute orientation of molecules at liquid interfaces by sum frequency generation (SFG) is reported. It is based on measurements of the orientations of two nonparallel vibrationally active chromophores in the molecule of interest combined with a rotation matrix formulation to obtain the absolute molecular orientation. We chose m-tolunitrile, a planar molecule adsorbed to the air/water interface, as a proof-of-method experiment. Quantitative analysis of different polarization sum frequency intensities facilitate unique peak assignments of the methyl and nitrile groups of m-tolunitrile. The SFG analysis of the measurement yields a nitrile group tilting at 53 degrees to the surface normal, and the C3 axis of the methyl group is almost upright at 23 degrees with respect to the surface normal. Using a rotation matrix formulation, we found that the angle between the surface plane and the m-tolunitrile molecular plane is 70 degrees. PMID:16471739

Rao, Yi; Comstock, Matthew; Eisenthal, Kenneth B

2006-02-01

310

Absolute Plate Motions by Boundary Velocity Minimizations  

Microsoft Academic Search

The main interaction of the interior with the lithosphere is as a material source and sink. An absolute reference frame defined by minimizing the translational motion of tectonic plate boundaries differs by 0.6 cm\\/yr from a frame defined by hot spo_t traces and by 0.4 cm\\/yr from the frame defined by the most plausible model of drag forces on the

William M. Kaula

1975-01-01

311

On absolute CM-periods, II  

Microsoft Academic Search

For a CM-fieldK, Shimura defined the period symbolpK by factorizing periods of abelian varieties with complex multiplication. We define the absolute period symbolgK using division values of the multiple gamma function and conjecture that pK coincides with gK up to the multiplication by algebraic numbers. Taking the action of Gal(Q Q) into account, we present a refined version of this

Hiroyuki Yoshida

1998-01-01

312

Absolute photoionization cross sections of atomic oxygen  

NASA Technical Reports Server (NTRS)

The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

Samson, J. A. R.; Pareek, P. N.

1985-01-01

313

Absolute photoionization cross sections of atomic oxygen  

NASA Technical Reports Server (NTRS)

The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

Samson, J. A. R.; Pareek, P. N.

1982-01-01

314

Absolute negative mobility in a vibrational motor  

NASA Astrophysics Data System (ADS)

An anomalous transport phenomenon termed absolute negative mobility (ANM) was observed in a vibrational motor, where an additional time-periodic signal filled the role usually played by noise in a Brownian motor. Within a tailored parameter regime, the ANM behavior is maximized at two regimes upon variation of the bias. The observed ANM still survives at a wide range of the driving strength and angular frequency of the additional signal.

Du, Luchun; Mei, Dongcheng

2012-01-01

315

Nepal and the Americas: Can Electromagnetic Field (EMF) Signals Be Detected There That Yield Information About Culturally Dictated Spiritual Values, and Can Computers Interface Their Assessment?  

NASA Astrophysics Data System (ADS)

Nepal has a particularly rich tradition of culturally developed views on the material and spiritual worlds, and also has a powerful natural environment that may generate EMFs in conjunction with natural phenomena. We have an interest in determining whether these can be detected by portable technological means, and recording such data on notebook-type computers for analysis and evaluation. One goal is to assess whether historic Native Americans, such as Maine's and New Hampshire's Molly Ockett, may have been motivated in their selection of special, and perhaps, to them, "sacred" sites for their attention and as possible burial sites. Some of these may have been chosen on the basis of the EMFs that seem to emanate from them, and their assessment of what they meant to their worldviews. Do some Amerindians consider the EMF and reincarnation as requiring their rejection of material aspects of existence? Could other traditional cultures, or even suicidal terrorists, be sensitive to "information" they may receive from the EMF?

Aryal, Sanjita; Mc Leod, Roger D.; Mc Leod, David M.

2002-10-01

316

Phase Transformations and Thermodynamic Behavior of the YBa sub 2 Cu sub 3 O sub X System Via (Electromotive Force) EMF Measurements.  

National Technical Information Service (NTIS)

EMF measurements of oxygen fugacities as a function of stoichiometry in YBa sub 2 Cu sub 3 O/sub x/ were made in the temperature range 650-750/degree/C by means of an oxygen titration technique with a ZrO sub 2 electrolyte doped with Y sub 2 O sub 3 . Fro...

M. Tetenbaum A. Brown M. Blander

1988-01-01

317

The role of the JAK2STAT3 pathway in pro-inflammatory responses of EMF-stimulated N9 microglial cells  

Microsoft Academic Search

BACKGROUND: In several neuropathological conditions, microglia can become overactivated and cause neurotoxicity by initiating neuronal damage in response to pro-inflammatory stimuli. Our previous studies have shown that exposure to electromagnetic fields (EMF) activates cultured microglia to produce tumor necrosis factor (TNF)-? and nitric oxide (NO) through signal transduction involving the activator of transcription STAT3. Here, we investigated the role of

Xuesen Yang; Genlin He; Yutong Hao; Chunhai Chen; Maoquan Li; Yuan Wang; Guangbin Zhang; Zhengping Yu

2010-01-01

318

Human responses to weak EMF are biologically plausible because “ordinary” electrically excitable channels can account for an extreme sensitivity to electric fields in sharks and related species  

Microsoft Academic Search

The possibility that humans could respond to weak electric or magnetic fields (EMF) is often dismissed on the basis that our species does not have the type of cellular or molecular apparatus that enables other animals to be “hypersensitive” to electric fields. In this paper we examine the proposition that extreme electrical hypersensitivity in sharks and similar species could be

Howard Wachtel; David Beeman; Jay Pottenger

1998-01-01

319

Impedance of a Spacecraft-Borne Antenna in the Magnetospheric Plasma and Quasi-Equilibrium Noise EMF in the Lower-Hybrid Frequency Band  

NASA Astrophysics Data System (ADS)

We present analytical and numerical estimations of the value and frequency dependence of the impedance and noise electromotive force (EMF) in the context of the conditions which correspond to the trajectories and parameters of the antennas borne by geophysical monitoring satellites. The estimations were obtained for two circular orbits at altitudes of 600 and 1200 km over the Earth's surface in the frequency range from 20 to 120 kHz, which corresponded to the area of the lower-hybrid resonance, where a higher level of noise emissions is observed at the altitudes under consideration. It is shown that near the lower-hybrid resonance frequency, the real part of the antenna impedance is determined by the resonant "monopole" loss by radiation of quasipotential waves. In the nonresonant frequency band (at the frequencies below the frequency of the lowerhybrid resonance), the antenna reactance is determined by the transit loss, which is, however, low as compared with the resonant loss. When the noise was calculated, the medium was assumed to be a two-temperature plasma. The spectral density of the power of the noise EMF lies in the range and is determined mainly by suprathermal electrons. In the nonresonant frequency band, the efficient temperature of noise radiation is equal to the temperature of the "cold" plasma component, and the antenna reactance is determined by the transit loss, i.e., the level of the noise EMF is low as compared with the EMF in the resonant frequency band.

Chugunov, Yu. V.; Grach, V. S.; Pasmanik, D. L.

2013-07-01

320

A comparative study of rotor flux based MRAS and back EMF based MRAS speed estimators for speed sensorless vector control of induction machines  

Microsoft Academic Search

This paper seeks to provide a direct comparison between two types of induction motor MRACS based speed estimators, one based on the rotor flux and the other based on the back EMF. Comparison between the two techniques is made through computer simulations and verified with experimental results obtained from a digital signal processor (DSP) based vector control system. The performances

Mohammad N. Marwali; Ali Keyhani

1997-01-01

321

Clinical thermal imaging today  

Microsoft Academic Search

In order to make thermal imaging a universally acceptable clinical technique, one must try to understand what is being observed, and what the observation signifies. One must also prove the validity of hypotheses about underlying causes of a given local hyper or hypothermia. Such an understanding is absolutely necessary before one can adapt the available technology to meet given clinical

M. Anbar

1998-01-01

322

Wf/pc SV Observation: Absolute Flux Standards  

NASA Astrophysics Data System (ADS)

The purpose of this calibration is to obtain data on flux standards through WF/PC. These stars are about 14 magnitude. This proposal replaces previous proposals ABSOLUTE UV CALIBRATION (1322) and ABSOLUTE FLUX STANDARDS (1331).

Westphal, J.

1990-07-01

323

Absolute Radiometric Calibration of EUNIS-06  

NASA Technical Reports Server (NTRS)

The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.

Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.

2007-01-01

324

Absolute calibration of the Auger fluorescence detectors  

SciTech Connect

Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the combined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.

Bauleo, P.; Brack, J.; Garrard, L.; Harton, J.; Knapik, R.; Meyhandan, R.; Rovero, A.C.; /Buenos Aires, IAFE; Tamashiro, A.; Warner, D.

2005-07-01

325

Absolute Priority for a Vehicle in VANET  

NASA Astrophysics Data System (ADS)

In today's world, traffic jams waste hundreds of hours of our life. This causes many researchers try to resolve the problem with the idea of Intelligent Transportation System. For some applications like a travelling ambulance, it is important to reduce delay even for a second. In this paper, we propose a completely infrastructure-less approach for finding shortest path and controlling traffic light to provide absolute priority for an emergency vehicle. We use the idea of vehicular ad-hoc networking to reduce the imposed travelling time. Then, we simulate our proposed protocol and compare it with a centrally controlled traffic light system.

Shirani, Rostam; Hendessi, Faramarz; Montazeri, Mohammad Ali; Sheikh Zefreh, Mohammad

326

Continuum limit of electrostatic gyrokinetic absolute equilibrium  

NASA Astrophysics Data System (ADS)

Electrostatic gyrokinetic absolute equilibria with continuum velocity field are obtained through the partition function and through the Green function of the functional integral. The new results justify and explain the prescription for quantization/discretization or taking the continuum limit of velocity. The mistakes in the Appendix D of our earlier work [J.-Z. Zhu and G. W. Hammett, Phys. Plasmas 17, 122307 (2010)] are explained and corrected. If the lattice spacing for discretizing velocity is big enough, all the invariants could concentrate at the lowest Fourier modes in a negative-temperature state, which might indicate a possible variation of the dual cascade picture in 2D plasma turbulence.

Zhu, Jian-Zhou

2012-06-01

327

Note: Real-time absolute air refractometer.  

PubMed

We present a real-time absolute air refractometer benefiting from the synthetic pseudo-wavelength (SPW) method. Based on laser heterodyne interferometry, the SPW method uses three vacuum cells with specific lengths to synthesize a set of synthetic pseudo-wavelengths, by combination of which the refractive index can be determined directly without ambiguity. In addition, owing to the parallel arrangement of the vacuum cells in the optical path, the measured data can be collected simultaneously so that one measurement process can be less than 2 ms. The real-time feature makes it possible for instantaneous compensation for laser interferometers. PMID:24880432

Huang, Pei; Zhang, Jitao; Li, Yan; Wei, Haoyun

2014-05-01

328

Absolute method of measuring magnetic susceptibility  

USGS Publications Warehouse

An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

Thorpe, A.; Senftle, F. E.

1959-01-01

329

Continuum limit of electrostatic gyrokinetic absolute equilibrium  

SciTech Connect

Electrostatic gyrokinetic absolute equilibria with continuum velocity field are obtained through the partition function and through the Green function of the functional integral. The new results justify and explain the prescription for quantization/discretization or taking the continuum limit of velocity. The mistakes in the Appendix D of our earlier work [J.-Z. Zhu and G. W. Hammett, Phys. Plasmas 17, 122307 (2010)] are explained and corrected. If the lattice spacing for discretizing velocity is big enough, all the invariants could concentrate at the lowest Fourier modes in a negative-temperature state, which might indicate a possible variation of the dual cascade picture in 2D plasma turbulence.

Zhu Jianzhou [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-06-15

330

Absolute and convective instabilities of shielded vortices  

NASA Astrophysics Data System (ADS)

We investigate the spatial instability of a parallel and axisymmetric vortex by employing a Chebyshev spectral method. The three-parameters rotating flow, of axial velocity U=a+e^-r^2 and centrifugally unstable azimuthal velocity W=qre^-r^?, exhibits a cyclonic core surrounded by an anticyclonic ring (with zero total circulation [Carton and Legras, J. Fluid Mech. 267, 53 (1994)]). The absolute-convective transition curves are located in the a-q plane for different azimuthal wavenumbers m=0, ^+_-1, ^+_-2, Reynolds numbers and values of ?. In the convectively unstable region, the sensitivity of the eigenfunction components to ? is also discussed.

Sellier, Antoine; Montijn, Carolynne

1999-11-01

331

Dynamic control of adsorption sensitivity for photo-EMF-based ammonia gas sensors using a wireless network.  

PubMed

This paper proposes an adsorption sensitivity control method that uses a wireless network and illumination light intensity in a photo-electromagnetic field (EMF)-based gas sensor for measurements in real time of a wide range of ammonia concentrations. The minimum measurement error for a range of ammonia concentration from 3 to 800 ppm occurs when the gas concentration magnitude corresponds with the optimal intensity of the illumination light. A simulation with LabView-engineered modules for automatic control of a new intelligent computer system was conducted to improve measurement precision over a wide range of gas concentrations. This gas sensor computer system with wireless network technology could be useful in the chemical industry for automatic detection and measurement of hazardous ammonia gas levels in real time. PMID:22346680

Vashpanov, Yuriy; Choo, Hyunseung; Kim, Dongsoo Stephen

2011-01-01

332

Dynamic Control of Adsorption Sensitivity for Photo-EMF-Based Ammonia Gas Sensors Using a Wireless Network  

PubMed Central

This paper proposes an adsorption sensitivity control method that uses a wireless network and illumination light intensity in a photo-electromagnetic field (EMF)-based gas sensor for measurements in real time of a wide range of ammonia concentrations. The minimum measurement error for a range of ammonia concentration from 3 to 800 ppm occurs when the gas concentration magnitude corresponds with the optimal intensity of the illumination light. A simulation with LabView-engineered modules for automatic control of a new intelligent computer system was conducted to improve measurement precision over a wide range of gas concentrations. This gas sensor computer system with wireless network technology could be useful in the chemical industry for automatic detection and measurement of hazardous ammonia gas levels in real time.

Vashpanov, Yuriy; Choo, Hyunseung; Kim, Dongsoo Stephen

2011-01-01

333

Floridas Miami Tequesta Indian Site, Its Calusa Indian Locations, the Matacumbe Keys, and Orlandos Wikiwa Springs Generate Environmentally Significant EMFs.  

NASA Astrophysics Data System (ADS)

Florida purchased the Tequesta ([Langue] doc Christ Spirit-signal) Indian site along the Miami River site that vigorously pulsates with even minor rainstorms entering or leaving the area. Although there is a laughable chimera of a fountain of youth associated with Ponce de Leons discovery of the Florida peninsula in about AD 1513, the Calusa (Royal Christ Jesus Spirit-signal) Indian Nation has an associated significance with EMF signals they possibly monitored throughout their area of activity. Our efforts have also led to the investigation of cultural and other influences implied by the Matacumbe Keys that indicate a shared commonality of awareness with Native Americans of the northeast such as Metacomet, or regions like Maines Grand Lake Matagamon and its associated electromagnetic Spirit Signal. Wikiwa Springs near Orlando shares much with Massachusetts (adherent of serpent Jesus Christ Spirit-signal) Natick, and New Hampshires Naticook Island. These are the locales of environmentally sensitive instrumentation.

Mac Dougall, Jean S.; Mc Leod, Roger D.; Mc Leod, David M.

2003-10-01

334

Measurement of activity of gallium in solid Pt-Ga alloys by EMF method using zirconia as solid electrolyte  

SciTech Connect

EMF of galvanic cells with zirconia solid electrolytes was measured to determine the activity of gallium in solid Pt-Ga alloys in the temperature range 970--1,170 K in the entire composition range. Fe, Fe{sub x}O and/or Ga, Ga{sub 2}O{sub 3} mixtures were used as the reference electrode. Activity of Ga at 1,100 K changes largely in log scale in Pt-rich {alpha}-solid solution, GaPt{sub 3}, and GaPt phases; slightly in GaPt{sub 2}, Ga{sub 3}Pt{sub 2}, and Ga{sub 2}Pt phases; and moderately in Ga{sub 3}Pt{sub 5} and Ga{sub 7}Pt{sub 3} phases. The free energies of formation of each phase at 1,100 K are calculated from the experimental data.

Katayama, Iwao; Makino, Teruki; Iida, Takamichi [Osaka Univ., Suita, Osaka (Japan)

1995-08-01

335

Mechanical Models for Absolute Plate Motions in the Early Tertiary  

Microsoft Academic Search

To test hypotheses relating the absolute velocities of the plates to driving force models for the present plate system, we have determined the absolute plate motions in the early Tertiary for a number of force models using the assumption that these forces exert no net torque on the lithosphere. All absolute motion models are based on a self-consistent set of

Sean C. Solomon; Norman H. Sleep; Donna M. Jurdy

1977-01-01

336

Using, Seeing, Feeling, and Doing Absolute Value for Deeper Understanding  

ERIC Educational Resources Information Center

Using sticky notes and number lines, a hands-on activity is shared that anchors initial student thinking about absolute value. The initial point of reference should help students successfully evaluate numeric problems involving absolute value. They should also be able to solve absolute value equations and inequalities that are typically found in…

Ponce, Gregorio A.

2008-01-01

337

Worst-Case Absolute Loss Bounds for Linear Learning Algorithms  

Microsoft Academic Search

The absolute loss is the absolute difference between the de- sired and predicted outcome. I demonstrate worst-case upper bounds on the absolute loss for the perceptron algorithm and an exponentiated update algorithm related to the Weighted Majority algorithm. The bounds characterize the behavior of the algorithms over any sequence of trials, where each trial consists of an example and a

Tom Bylander

1997-01-01

338

Absolute Spectrophotometry of 237 Open Cluster Stars  

NASA Astrophysics Data System (ADS)

We present absolute spectrophotometry of 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M 39. The observations were taken using the Wampler single-channel scanner (Wampler 1966) on the Crossley 0.9m telescope at Lick Observatory from July 1973 through December 1974. 21 bandpasses spanning the spectral range 3500 Angstroms to 7780 Angstroms were observed for each star, with bandwiths ranging from 32Angstroms to 64 Angstroms. Data are standardized to the Hayes--Latham (1975) system. Our measurements are compared to filter colors on the Johnson BV, Stromgren ubvy, and Geneva U V B_1 B_2 V_1 G systems, as well as to spectrophotometry of a few stars published by Gunn, Stryker & Tinsley and in the Spectrophotometric Standards Catalog (Adelman; as distributed by the NSSDC). Both internal and external comparisons to the filter systems indicate a formal statistical accuracy per bandpass of 0.01 to 0.02 mag, with apparent larger ( ~ 0.03 mag) differences in absolute calibration between this data set and existing spectrophotometry. These data will comprise part of the spectrophotometry that will be used to calibrate the Beijing-Arizona-Taipei-Connecticut Color Survey of the Sky (see separate paper by Burstein et al. at this meeting).

Clampitt, L.; Burstein, D.

1994-12-01

339

Absolute stereochemistry of altersolanol A and alterporriols.  

PubMed

The absolute stereochemistry of altersolanol A (1) was established by observing a positive exciton couplet in the circular dichroism (CD) spectrum of the C3,C4-O-bis(2-naphthoyl) derivative 10 and by chemical correlations with known compound 8. Before the discussion, the relative stereochemistry of 1 was confirmed by X-ray crystallographic analysis. The shielding effect at C7'-OMe group by C1-O-benzoylation established the relative stereochemical relationship between the C8-C8' axial bonding and the C1-C4/C1'-C4' polyol moieties of alterporriols E (3), an atropisomer of the C8-C8' dimer of 1. As 3 could be obtained by dimerization of 1 in vitro, the absolute configuration of its central chirality elements (C1-C4) must be identical to those of 1. Spectral comparison between the experimental and theoretical CD spectra supported the above conclusion. Axial stereochemistry of novel C4-O-deoxy dimeric derivatives, alterporriols F (4) and G (5), were also revealed by comparison of their CD spectra to those of 2 and 3. PMID:22180221

Kanamaru, Saki; Honma, Miho; Murakami, Takanori; Tsushima, Taro; Kudo, Shinji; Tanaka, Kazuaki; Nihei, Ken-Ichi; Nehira, Tatsuo; Hashimoto, Masaru

2012-02-01

340

The absolute threshold of cone vision  

PubMed Central

We report measurements of the absolute threshold of cone vision, which has been previously underestimated due to sub-optimal conditions or overly strict subjective response criteria. We avoided these limitations by using optimized stimuli and experimental conditions while having subjects respond within a rating scale framework. Small (1? fwhm), brief (34 msec), monochromatic (550 nm) stimuli were foveally presented at multiple intensities in dark-adapted retina for 5 subjects. For comparison, 4 subjects underwent similar testing with rod-optimized stimuli. Cone absolute threshold, that is, the minimum light energy for which subjects were just able to detect a visual stimulus with any response criterion, was 203 ± 38 photons at the cornea, ?0.47 log units lower than previously reported. Two-alternative forced-choice measurements in a subset of subjects yielded consistent results. Cone thresholds were less responsive to criterion changes than rod thresholds, suggesting a limit to the stimulus information recoverable from the cone mosaic in addition to the limit imposed by Poisson noise. Results were consistent with expectations for detection in the face of stimulus uncertainty. We discuss implications of these findings for modeling the first stages of human cone vision and interpreting psychophysical data acquired with adaptive optics at the spatial scale of the receptor mosaic.

Koeing, Darran; Hofer, Heidi

2013-01-01

341

Does Exposure to a Radiofrequency Electromagnetic Field Modify Thermal Preference in Juvenile Rats?  

PubMed Central

Some studies have shown that people living near a mobile phone base station may report sleep disturbances and discomfort. Using a rat model, we have previously shown that chronic exposure to a low-intensity radiofrequency electromagnetic field (RF-EMF) was associated with paradoxical sleep (PS) fragmentation and greater vasomotor tone in the tail. Here, we sought to establish whether sleep disturbances might result from the disturbance of thermoregulatory processes by a RF-EMF. We recorded thermal preference and sleep stage distribution in 18 young male Wistar rats. Nine animals were exposed to a low-intensity RF-EMF (900 MHz, 1 V.m?1) for five weeks and nine served as non-exposed controls. Thermal preference was assessed in an experimental chamber comprising three interconnected compartments, in which the air temperatures (Ta) were set to 24°C, 28°C and 31°C. Sleep and tail skin temperature were also recorded. Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (?1.6°C) which confirmed previous data. During the light period, the exposed group preferred to sleep at Ta?=?31°C and the controls preferred Ta?=?28°C. The mean sleep duration in exposed group was significantly greater (by 15.5%) than in control group (due in turn to a significantly greater amount of slow wave sleep (SWS, +14.6%). Similarly, frequency of SWS was greater in exposed group (by 4.9 episodes.h?1). The PS did not differ significantly between the two groups. During the dark period, there were no significant intergroup differences. We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures. The shift in preferred temperature might result from a cold thermal sensation. The change in sleep stage distribution may involve signals from thermoreceptors in the skin. Modulation of SWS may be a protective adaptation in response to RF-EMF exposure.

Pelletier, Amandine; Delanaud, Stephane; de Seze, Rene; Bach, Veronique; Libert, Jean-Pierre; Loos, Nathalie

2014-01-01

342

Absolute Cavity Pyrgeometer to Measure the Absolute Outdoor Longwave Irradiance with Traceability to International System of Units, SI  

SciTech Connect

This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180{sup o} view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U{sub 95}) of {+-}3.96 W m{sup 02} with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m{sup 2} lower than that measured by the two pyrgeometers that are traceable to WISG, with a standard deviation of {+-}0.7 W m{sup -2}. These results suggest that the ACP design might be used for addressing the need to improve the international reference for broadband outdoor longwave irradiance measurements.

Reda, I.; Zeng, J.; Scheuch, J.; Hanssen, L.; Wilthan, B.; Myers, D.; Stoffel, T.

2012-03-01

343

Absolute proper motions of globular clusters  

NASA Astrophysics Data System (ADS)

The absolute proper motions for a total of 92 globular clusters of the Milky Way (60% of all clusters included in the catalogue published by Harris) are inferred from the UCAC2 proper motions of their likely member stars. The median formal error of the cluster proper motions is equal to 0.8marcsecyear-1 in both right ascension and declination, whereas the proper-motion errors of individual clusters range from 0.2 to 3marcsecyear-1. Tests performed demonstrate the overall validity of the cluster motions; the resulting transverse velocities remain, on the average, virtually constant out to a heliocentric distance of 15kpc and the full space velocity of most of the clusters relative to the Galactic centre remains, on the average, unchanged near 190kms-1 out to a Galactocentric distance of about 20kpc, in agreement with the overall isothermal structure of the Galactic halo.

Dambis, A. K.

2006-04-01

344

The first absolute gravity measurements in Indonesia  

NASA Astrophysics Data System (ADS)

For the purposes of the calibration of the superconducting gravimeter (SG) in Bandung and the establishment of the absolute gravity (AG) points, we carried out AG measurements for the first time in Indonesia in November 2002. The measurements in Bandung were conducted between November 15th and 20th by means of a FG5 (#210), and 14,520 effective drops were obtained. The gravity value newly determined at the AG point in Bandung is 977976701.2 ?gal (1 ?gal = 10 -8 ms -2) and the scale factor for the SG is -52.22 ?gal/V. We also established another AG point in Yogyakarta near Merapi volcano and carried out AG measurements in Yogyakarta between November 22nd and 26th. The gravity value determined for this station is 978203093.5 ?gal.

Fukuda, Yoichi; Higashi, Toshihiro; Takemoto, Shuzo; Abe, Maiko; Dwipa, Sjafra; Kusuma, Dendi Surya; Andan, Achmad; Doi, Koichiro; Imanishi, Yuichi; Arduino, Giuseppe

2004-10-01

345

Absolute rate calculations. Proton transfers in solution.  

PubMed

The reaction path of the intersecting-state model is used in transition-state theory with the semiclassical correction for tunneling (ISM/scTST) to calculate the rates of proton-transfer reactions from hydrogen-bond energies, reaction energies, electrophilicity indices, bond lengths, and vibration frequencies of the reactive bonds. ISM/scTST calculations do not involve adjustable parameters. The calculated proton-transfer rates are within 1 order of magnitude of the experimental ones at room temperature, and cover very diverse systems, such as deprotonations of nitroalkanes, ketones, HCN, carboxylic acids, and excited naphthols. The calculated temperature dependencies and kinetic isotope effects are also in good agreement with the experimental data. These calculations elucidate the roles of the reaction energy, electrophilicity, structural parameters, hydrogen bonds, tunneling, and solvent in the reactivity of acids and bases. The efficiency of the method makes it possible to run absolute rate calculations through the Internet. PMID:17249748

Barroso, Monica; Arnaut, Luis G; Formosinho, Sebastião J

2007-02-01

346

Micron Accurate Absolute Ranging System: Range Extension  

NASA Technical Reports Server (NTRS)

The purpose of this research is to investigate Fresnel diffraction as a means of obtaining absolute distance measurements with micron or greater accuracy. It is believed that such a system would prove useful to the Next Generation Space Telescope (NGST) as a non-intrusive, non-contact measuring system for use with secondary concentrator station-keeping systems. The present research attempts to validate past experiments and develop ways to apply the phenomena of Fresnel diffraction to micron accurate measurement. This report discusses past research on the phenomena, and the basis of the use Fresnel diffraction distance metrology. The apparatus used in the recent investigations, experimental procedures used, preliminary results are discussed in detail. Continued research and equipment requirements on the extension of the effective range of the Fresnel diffraction systems is also described.

Smalley, Larry L.; Smith, Kely L.

1999-01-01

347

Three-map absolute moir contouring  

NASA Astrophysics Data System (ADS)

In the shadow-moir system, the period of the grating is varied by rotation of the grating, so the phase of the moir pattern is changed as well. By the selection of suitable rotation angles, three images at different positions of the grating are acquired to obtain the absolute distance from the object to the grating. A theoretical analysis is presented for the method, and some experiments have been done to verify the theoretical analysis. The results show that the method is fast and the accuracy is better than 10 m. The measurable range is directly proportional to the period of the grating and inversely proportional to the angles at which the grating is rotated.

Xie, Xinjun; Atkinson, John T.; Lalor, Michael J.; Burton, David R.

1996-12-01

348

Absolute radiometric calibration of the Thematic Mapper  

NASA Technical Reports Server (NTRS)

Calibration data for the solar reflective bands of the Landsat-5 TM obtained from five in-flight absolute radiometric calibrations from July 1984-November 1985 at White Sands, New Mexico are presented and analyzed. Ground reflectance and atmospheric data were utilized to predict the spectral radiance at the entrance pupil of the TM and the average number of digital counts in each TM band. The calibration of each of the TM solar reflective bands was calculated in terms of average digital counts/unit spectral radiance for each band. It is observed that for the 12 reflectance-based measurements the rms variation from the means as a percentage of the mean is + or - 1.9 percent; for the 11 measurements in the IR bands, it is + or - 3.4 percent; and the rms variation for all 23 measurements is + or - 2.8 percent.

Slater, P. N.; Biggar, S. F.; Holm, R. G.; Jackson, R. D.; Mao, Y.

1986-01-01

349

MAGSAT: Vector magnetometer absolute sensor alignment determination  

NASA Technical Reports Server (NTRS)

A procedure is described for accurately determining the absolute alignment of the magnetic axes of a triaxial magnetometer sensor with respect to an external, fixed, reference coordinate system. The method does not require that the magnetic field vector orientation, as generated by a triaxial calibration coil system, be known to better than a few degrees from its true position, and minimizes the number of positions through which a sensor assembly must be rotated to obtain a solution. Computer simulations show that accuracies of better than 0.4 seconds of arc can be achieved under typical test conditions associated with existing magnetic test facilities. The basic approach is similar in nature to that presented by McPherron and Snare (1978) except that only three sensor positions are required and the system of equations to be solved is considerably simplified. Applications of the method to the case of the MAGSAT Vector Magnetometer are presented and the problems encountered discussed.

Acuna, M. H.

1981-01-01

350

[Effect of doxorubicine and heterogenous electromagnetic and thermal fields on the nonlinear dynamics of carcinoma Guerin development].  

PubMed

While local hyperthermia application the intratumoral blood flow is enhancing, leading to oxygenation and vascular permeability for antitumoral medicines. The work objective was to investigate the dependence of the development kinetics in carcinoma Gereni (CG) from combined action of doxorubicin (DR) and the kind of thermal impact, a contact one--due to a contact delivery of heat from a water heater and without contact - due to the tumor electromagnetic irradiation (EMI) using heterogenous electromagnetic field (EMF). DR was injected to the animals in a mass concentration of 1,5 mg on 1 kg of their body mass. The DR injection, a contact heating and EMI were started on the 8th day after the tumor reinoculation and kept on conducting once a 2 days. The course had included 5 injections and/or 5 seances of a contact heating and/or EMF. The combined action of DR and EMI, using spatially heterogenous EMF of applicator in environment of physiological hyperthermia, have had influenced mostly the inhibition of a nonlinear dynamics in CG development. Antitumoral action of DR in the animals with CG was influenced by thermal and nonthermal effects, which were initiated by spatially heterogenous EMF. Nonlinear dynamics of a CG development in animals did not depend from horizontal direction of isolines of a spatially heterogenous EMF of inductive applicator towards the tumor and duration of the irradiation procedure (15 or 30 minutes) after DR injection. The data obtained were exploited in clinical practice for the inductothermy optimal regimes elaboration while conducting complex treatment of patients, suffering oncological diseases. PMID:20825095

Orel, V E; Dziatkovs'ka, I I; Nikolov, M O; Romanov, A V; Mel'nyk, Iu H; Dziatkovs'ka, N M

2010-07-01

351

The effect of extremely low frequency electromagnetic fields (ELF-EMF) on the frequency of micronuclei and sister chromatid exchange in human lymphocytes induced by benzo( a)pyrene  

Microsoft Academic Search

The interaction of extremely low frequency electromagnetic fields (ELF-EMF) on the frequency of micronuclei (MN) and sister chromatid exchange (SCE) induced by benzo(a)pyrene (BP) in human lymphocytes was examined. A 60 Hz ELF-EMF of 0.8 mT field strength was applied either alone or with the tumor initiator, BP for 24 h. The frequencies of MN and SCE induced by BP

Yoon Hee Cho; Hai Won Chung

2003-01-01

352

A novel determination of thermodynamic activities of metals in an AISI 316 stainless steel by a metastable emf method  

NASA Astrophysics Data System (ADS)

An emf technique was adopted for the first time for direct determination of thermodynamic activities of all major metallic components, namely, Fe, Cr, Ni and Mn in a commercial grade AISI 316 stainless steel in the temperature range of approximately 800 to 1200 K. The viability of this method was initially established in the case of chromium activity measurements which could be compared with literature values. For this purpose galvanic cells with M/MF 2 and [M] 316ss/MF 2 (M = Fe, Cr, Ni or Mn) were used, employing single crystal CaF 2 as the electrolyte. In addition, Mo activitiy in this alloy was measured using the emf of the galvanic cell, Pt, Mo, MoO 2/7 YDT/MoO 2, [Mo] 316ss, Pt The activities determined by these galvanic cells could be represented as follows: log a Cr(±0.02) = -0.577 + 69.1/T , log a Ni(±0.02) = 0.589 - 800.31/T , log a Fe(±0.01) = 0.179 - 248.54/T , log a Mn(±0.01) = 0.742 - 2581.40/T , log a Mo(±0.05) = -4.548 + 3148.48/T . These activities were used to compute the threshold oxygen levels in Na(l)/AISI 316 stainless steel system for the formation of the corrosion products, viz., NaCrO 2, Na 4FeO 3, MnO and NaMnO 2. These data in conjunction with the carbon activity in this alloy reported in the literature, and initial composition of the M 23C 6, phase, could lead to the estimation of the Gibbs energy change for a typical reaction, 2.571Cr + 0.732Fe + 0.303Mo + 0.226Ni + C M 23/6C , as follows: ?G of,T(M 23/6C, s) (kJ) = -29.16 - 0.0522T (K) .

Azad, A. M.; Sreedharan, O. M.; Gnanamoorthy, J. B.

1987-01-01

353

Absoluteness of Velocity Produced by Accelerating Process and Absolute Space-time Theory with Variable Scales  

Microsoft Academic Search

It is proved by means of the dynamical effects of special relativity that velocity caused by accelerating process is not a relative concept. The influence of accelerating process should be considered in space-time theory. Besides the Newtonian absolute space-time theory with invariable space-time scales and the Einstein relative space-time theory with variable space-time scales, there exists the third space-time theory,

Mei Xiaochun

2006-01-01

354

Report on Toyota/Prius Motor Torque Capability, Torque Property, No-Load Back EMF, and Mechanical Losses, Revised May 2007  

SciTech Connect

In today's hybrid vehicle market, the Toyota/Prius drive system is currently considered the leader in electrical, mechanical, and manufacturing innovations. It is significant that in today's marketplace, Toyota is able to manufacture and sell the vehicle for a profit. This project's objective is to test the torque capability of the 2004 Prius motor and to analyze the torque properties relating to the rotor structure. The tested values of no-load back electromotive force (emf) and mechanical losses are also presented.

Hsu, J.S.; Ayers, C.W.; Coomer, C.L.; Wiles, R.H.; Burress, T.A.; Campbell, S.L.; Lowe, K.T.; Michelhaugh, R.T.

2007-05-31

355

Novel Back-EMF Detection Technique of Brushless DC Motor Drives for Wide Range Control Without Using Current and Position Sensors  

Microsoft Academic Search

This paper presents a new back-electromotive force (EMF) detection technique which provides wide range control for brushless dc motor (BLDCM) drives. As compared with previous techniques which can be used either for low duty-ratio control or for high duty-ratio control only, the proposed technique deals with the above-mentioned problem to give both low and high duty-ratio control while not invoking

Yen-Shin Lai; Yong-Kai Lin

2008-01-01

356

Phase Theory account of absolutive extraction in Tagalog  

Microsoft Academic Search

In Tagalog, and other syntactically ergative languages, only absolutive DPs are able to undergo A'-movement. This paper proposes a mechanism which correlates this restriction with absolutive case-checking within the theory of Multiple Spell-Out. I propose that T checks absolutive case only in intransitive clauses like antipassives, while v does so in transitive clauses. v is also able to host an

Edith Aldridge

357

Reconciling late Neogene Pacific absolute and relative plate motion changes  

Microsoft Academic Search

New models of Pacific absolute plate motion relative to hot spots and models of relative plate motion involving the Pacific plate all agree there was a significant change in the late Neogene (Chron 3A, ?5.89 Ma), reflecting a more northerly absolute motion than previously determined. As Pacific absolute plate motion became slightly more northerly, left-stepping transform segments came under compression.

Paul Wessel; Loren W. Kroenke

2007-01-01

358

Absolute nuclear material assay using count distribution (LAMBDA) space  

DOEpatents

A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

2012-06-05

359

Antifungal activity of tuberose absolute and some of its constituents.  

PubMed

The antifungal activity of the absolute of tuberose (Polianthes tuberosa ) and some of its constituents were evaluated against the mycelial growth of Colletotrichum gloeosporioides on potato-dextrose-agar medium. Tuberose absolute showed only mild activity at a concentration of 500 mg/L. However, three constituents present in the absolute, namely geraniol, indole and methyl anthranilate exhibited significant activity showing total inhibition of the mycelial growth at this concentration. PMID:16106389

Nidiry, Eugene Sebastian J; Babu, C S Bujji

2005-05-01

360

Advanced Optical Terrain Absolute Navigation for Pinpoint Lunar Landing  

Microsoft Academic Search

\\u000a Pin-point landing can only be achieved developing precise Absolute Navigation systems. Craters, for their intrinsic properties,\\u000a are one of the most suitable and robust features identifiable in lunar landscape. The Optical Terrain Absolute Navigation\\u000a (OTAN) system provides absolute navigation features and is composed by two main parts: the off-line part, focused on the extraction\\u000a of the Landmark Database; the on-line

Marco Mammarella; Marcos Avilés Rodrigálvarez; Andrea Pizzichini; Ana María Sánchez Montero

361

Synergistic effect of EMF-BEMER-type pulsed weak electromagnetic field and HPMA-bound doxorubicin on mouse EL4 T-cell lymphoma.  

PubMed

We have investigated the effects of low-frequency pulsed electromagnetic field (LF-EMF) produced by BEMER device on experimental mouse T-cell lymphoma EL4 growing on conventional and/or athymic (nude) mice. Exposure to EMF-BEMER slowed down the growth of tumor mass and prolonged the survival of experimental animals. The effect was more pronounced in immuno-compromised nude mice compared to conventional ones. Acceleration of tumor growth was never observed. No measurable levels of Hsp 70 or increased levels of specific anti-EL4 antibodies were detected in the serum taken from experimental mice before and at different intervals during the experiment, i.e. before solid tumor appeared, at the time of its aggressive growth, and at the terminal stage of the disease. A significant synergizing antitumor effect was seen when EL4 tumor-bearing mice were simultaneously exposed to EMF-BEMER and treated with suboptimal dose of synthetic HPMA copolymer-based doxorubicin, DOX(HYD)-HPMA. Such a combination may be especially useful for heavily treated patients suffering from advanced tumor and requiring additional aggressive chemotherapy which, however, at that time could represent almost life-threatening way of medication. PMID:21981636

?íhová, Blanka; Etrych, Tomáš; Šírová, Milada; Tomala, Jakub; Ulbrich, Karel; Ková?, Marek

2011-12-01

362

Absolute configuration of naturally occurring glabridin.  

PubMed

The title compound {systematic name: 4-[(3R)-8,8-dimethyl-3,4-dihydro-2H-pyrano[2,3-f]chromen-3-yl]benzene-1,3-diol, commonly named glabridin}, C20H20O4, is a species-specific biomarker from the roots Glycyrrhiza glabra L. (European licorice, Fabaceae). In the present study, this prenylated isoflavan has been purified from an enriched CHCl3 fraction of the extract of the root, using three steps of medium-pressure liquid chromatography (MPLC) by employing HW-40F, Sephadex LH-20 and LiChroCN as adsorbents. Pure glabridin was crystallized from an MeOH-H2O mixture (95:5?v/v) to yield colorless crystals containing one molecule per asymmetric unit (Z' = 1) in the space group P212121. Although the crystal structure has been reported before, the determination of the absolute configuration remained uncertain. Stereochemical analysis, including circular dichroism, NMR data and an X-ray diffraction data set with Bijvoet differences, confirms that glabridin, purified from its natural source, is found only in a C3 R configuration. These results can therefore be used as a reference for the assignment of the configuration and enantiopurity of any isolated or synthetic glabridin sample. PMID:24192160

Simmler, Charlotte; Fronczek, Frank R; Pauli, Guido F; Santarsiero, Bernard D

2013-11-01

363

An absolute clock of the cosmos?  

NASA Astrophysics Data System (ADS)

In 1968-2005 different observers (mainly, one of the authors—V.M. Lyuty) performed numerous measurements of luminosity of the nucleus of the Seyfert galaxy NGC 4151. It is shown that ( a) luminosity of the object pulsated over 38 years with a period of 160.0106(7) min coinciding, within the error limits, with the well-known period P 0 = 160.0101(2) min of the enigmatic “solar” pulsations, and ( b) when registering oscillations of luminosity of NGC 4151 nucleus with the P 0 period, time moments of observations must be reduced to the earth instead of the sun, i.e., to the reference frame of the observer. The coherent P 0 oscillation is characterized, therefore, by invariability of both frequency and phase with respect to redshift z and the earth’s orbital motion, respectively. From these results it, thus, follows that the coherent P 0 oscillation seems to be of a true cosmological origin. The P 0 period itself might represent a course of the “cosmic clock” related to the existence of an absolute time of the Universe in Newton’s comprehension.

Kotov, V. A.; Lyuty, V. M.

2010-06-01

364

Elevation correction factor for absolute pressure measurements  

NASA Technical Reports Server (NTRS)

With the arrival of highly accurate multi-port pressure measurement systems, conditions that previously did not affect overall system accuracy must now be scrutinized closely. Errors caused by elevation differences between pressure sensing elements and model pressure taps can be quantified and corrected. With multi-port pressure measurement systems, the sensing elements are connected to pressure taps that may be many feet away. The measurement system may be at a different elevation than the pressure taps due to laboratory space or test article constraints. This difference produces a pressure gradient that is inversely proportional to height within the interface tube. The pressure at the bottom of the tube will be higher than the pressure at the top due to the weight of the tube's column of air. Tubes with higher pressures will exhibit larger absolute errors due to the higher air density. The above effect is well documented but has generally been taken into account with large elevations only. With error analysis techniques, the loss in accuracy from elevation can be easily quantified. Correction factors can be applied to maintain the high accuracies of new pressure measurement systems.

Panek, Joseph W.; Sorrells, Mark R.

1996-01-01

365

Relative and Absolute Detection Efficiency of WWLLN  

NASA Astrophysics Data System (ADS)

A recent upgrade to the World Wide Lightning Location Network (WWLLN) allows for the network to measure the far-field VLF radiated power of the detected strokes, this is in addition to the network locating the strokes in space and time. The network consists of 57 VLF antennas spread around the globe and is able to accurately locate most strokes to within ~10km in space, <30?s in time and with an average of 20% uncertainty in power. The capability to measure the radiated stroke power has enabled a first principles based model of the global relative detection efficiency of the network. By utilizing past comparisons of WWLLN to other ground based networks the absolute detection efficiency of the network can be estimated for the entire globe. The results of the relative WWLLN detection efficiency model are used to show the global distribution of strokes as seen by the network if it had uniform global coverage. Similarly the effects of a single VLF detector going offline are investigated for the regimes of sparse and dense detector coverage. The results are also used to show spatial, temporal and power distributions as seen by the detection efficiency corrected WWLLN.

Hutchins, M. L.; Holzworth, R. H.; Rodger, C. J.; Brundell, J. B.; McCarthy, M.

2011-12-01

366

Gyrokinetic Statistical Absolute Equilibrium and Turbulence  

SciTech Connect

A paradigm based on the absolute equilibrium of Galerkin-truncated inviscid systems to aid in understanding turbulence [T.-D. Lee, "On some statistical properties of hydrodynamical and magnetohydrodynamical fields," Q. Appl. Math. 10, 69 (1952)] is taken to study gyrokinetic plasma turbulence: A finite set of Fourier modes of the collisionless gyrokinetic equations are kept and the statistical equilibria are calculated; possible implications for plasma turbulence in various situations are discussed. For the case of two spatial and one velocity dimension, in the calculation with discretization also of velocity v with N grid points (where N + 1 quantities are conserved, corresponding to an energy invariant and N entropy-related invariants), the negative temperature states, corresponding to the condensation of the generalized energy into the lowest modes, are found. This indicates a generic feature of inverse energy cascade. Comparisons are made with some classical results, such as those of Charney-Hasegawa-Mima in the cold-ion limit. There is a universal shape for statistical equilibrium of gyrokinetics in three spatial and two velocity dimensions with just one conserved quantity. Possible physical relevance to turbulence, such as ITG zonal flows, and to a critical balance hypothesis are also discussed.

Jian-Zhou Zhu and Gregory W. Hammett

2011-01-10

367

Absolute Energy Calibration of the MINOS Detectors  

NASA Astrophysics Data System (ADS)

The MINOS experiment is designed to search for neutrino oscillations. A neutrino beam from Fermilab will be directed towards the Soudan Mine, 735 km away in Minnesota. The beam is sampled at Fermilab by a `Near' detector and in the mine by a `Far' detector. A comparison of the observed neutrino events at the two locations allows a measurement of the oscillation parameters to be made. Absolute calibration of the detectors is important when interpreting the oscillation data. To establish this, a third detector has been built: the Calibration Detector (CalDet). The same in basic design as the Near and Far detectors but smaller, the CalDet is being used to characterize the response of hadrons, electrons and muons of known energies in the MINOS detectors. Over the past two years, the CalDet has been exposed to a number of test beams at the CERN PS. This presentation will describe the overall MINOS calibration strategy as well as the design and performance of the CalDet.

Smith, Chris

2003-04-01

368

Absolute-convective instability of coaxial jets  

NASA Astrophysics Data System (ADS)

A well established route for the massive microencapsulation of labile materials, microorganisms, pharmaceutical principles, flavors, or any active ingredients of any kind involves the generation and breakup of coaxial capillary jets. Here, surface tension is the ultimate molding mechanism, and therefore experience teaches that the product quality is optimized within operating condition ranges where Weber and Capillary numbers attain limited values. These ranges allow for a precise control of the product structure. However, surface tension also mandates whether compound capillary jets may form or not: Weber and Capillary numbers maps exhibit ``hard'' boundaries where jets become locally unstable (absolutely unstable) as opposed to convectively unstable, and the product shows dramatic changes in structure (generally a degradation) across these boundaries. In this work we perform a linear spatiotemporal analysis of coaxial capillary jets to provide cartographic maps of viable regions in the Weber and Capillary numbers space. A discussion on the connection of these maps with the morphology of the resulting products is also given, together with comparisons with published experimental literature.

Ferrera, Conrado; Herrada, Miguel A.; Montanero, Jose M.; Ganan-Calvo, Alfonso M.

2008-11-01

369

Absolute and Convective Instability of a Liquid Jet  

NASA Technical Reports Server (NTRS)

The existence of absolute instability in a liquid jet has been predicted for some time. The disturbance grows in time and propagates both upstream and downstream in an absolutely unstable liquid jet. The image of absolute instability is captured in the NASA 2.2 sec drop tower and reported here. The transition from convective to absolute instability is observed experimentally. The experimental results are compared with the theoretical predictions on the transition Weber number as functions of the Reynolds number. The role of interfacial shear relative to all other relevant forces which cause the onset of jet breakup is explained.

Lin, S. P.; Hudman, M.; Chen, J. N.

1999-01-01

370

Oxygen potential measurements of Am 0.5Pu 0.5O 2-x by EMF method  

NASA Astrophysics Data System (ADS)

The dependence of the oxygen potentials on oxygen non-stoichiometry and temperature of Am 0.5Pu 0.5O 2-x has been obtained by the electromotive force (EMF) method with the cell: (Pt) air |Zr(Ca)O 2-x| Am 0.5Pu 0.5O 2-x (Pt). The x value of Am 0.5Pu 0.5O 2-x was changed at 1333 K over 0.02 < x ? 0.25 by the coulomb titration method. The temperature dependence of the oxygen potential was also measured over the range of 1173-1333 K. It was found that the oxygen potential decreased from -80 to -360 kJ mol -1 with increasing x from 0.021 to 0.22 at 1333 K and that it remained almost constant at -360 kJmol -1 around x = 0.23. It was concluded that Am 0.5Pu 0.5O 2-x should be composed of the single fluorite-type phase over 0.02 < x ? 0.22 and the mixed phases of fluorite-type and (Am, Pu) 9O 16 at around x = 0.23.

Otobe, Haruyoshi; Akabori, Mitsuo; Arai, Yasuo

2009-06-01

371

Thermodynamic and nonstoichiometric behavior of promising Hi-Tc cuprate systems via EMF measurements : a short review.  

SciTech Connect

Electromotive force (EMF) measurements of oxygen fugacities as a function of stoichiometry have been made on the YBa{sub 2}Cu{sub 3}O{sub x}, GdBa{sub 2}Cu{sub 3}O{sub x}, NdBa{sub 2}Cu{sub 3}O{sub x} and bismuth cuprate systems in the temperature range {approximately}400-750 C by means of an oxygen titration technique with an yttria-stabilized zirconia electrolyte. The shapes of the 400 C isotherms as a function of oxygen stoichiometry for the Gd and Nd cuprate systems suggest the presence of miscibility gaps at values of x that are higher than those in the YBa{sub 2}Cu{sub 3}O{sub x} system. For a given oxygen stoichiometry, oxygen partial pressures above GdBa{sub 2}Cu{sub 3}O{sub x} and NdBa{sub 2}Cu{sub 3}O{sub x} are higher (above x=6.5) than that for the promising YBa{sub 2}Cu{sub 3}O{sub x} system. A thermodynamic assessment and intercomparison of our partial pressure measurements with the results of related measurements will be presented.

Tetenbaum, M.

1999-02-24

372

A Liquid-Helium-Cooled Absolute Reference Cold Load forLong-Wavelength Radiometric Calibration  

SciTech Connect

We describe a large (78-cm) diameter liquid-helium-cooled black-body absolute reference cold load for the calibration of microwave radiometers. The load provides an absolute calibration near the liquid helium (LHe) boiling point, accurate to better than 30 mK for wavelengths from 2.5 to 25 cm (12-1.2 GHz). The emission (from non-LHe temperature parts of the cold load) and reflection are small and well determined. Total corrections to the LHe boiling point temperature are {le} 50 mK over the operating range. This cold load has been used at several wavelengths at the South Pole and at the White Mountain Research Station. In operation, the average LHe loss rate was {le} 4.4 l/hr. Design considerations, radiometric and thermal performance and operational aspects are discussed. A comparison with other LHe-cooled reference loads including the predecessor of this cold load is given.

Bensadoun, M.; Witebsky, C.; Smoot, George F.; De Amici,Giovanni; Kogut, A.; Levin, S.

1990-05-01

373

Absolute brightness temperature measurements at 3.5-mm wavelength. [of sun, Venus, Jupiter and Saturn  

NASA Technical Reports Server (NTRS)

Careful observations have been made at 86.1 GHz to derive the absolute brightness temperatures of the sun (7914 + or - 192 K), Venus (357.5 + or - 13.1 K), Jupiter (179.4 + or - 4.7 K), and Saturn (153.4 + or - 4.8 K) with a standard error of about three percent. This is a significant improvement in accuracy over previous results at millimeter wavelengths. A stable transmitter and novel superheterodyne receiver were constructed and used to determine the effective collecting area of the Millimeter Wave Observatory (MWO) 4.9-m antenna relative to a previously calibrated standard gain horn. The thermal scale was set by calibrating the radiometer with carefully constructed and tested hot and cold loads. The brightness temperatures may be used to establish an absolute calibration scale and to determine the antenna aperture and beam efficiencies of other radio telescopes at 3.5-mm wavelength.

Ulich, B. L.; Rhodes, P. J.; Davis, J. H.; Hollis, J. M.

1980-01-01

374

Absolute determination of local tropospheric OH concentrations  

NASA Technical Reports Server (NTRS)

Long path absorption (LPA) according to Lambert Beer's law is a method to determine absolute concentrations of trace gases such as tropospheric OH. We have developed a LPA instrument which is based on a rapid tuning of the light source which is a frequency doubled dye laser. The laser is tuned across two or three OH absorption features around 308 nm with a scanning speed of 0.07 cm(exp -1)/microsecond and a repetition rate of 1.3 kHz. This high scanning speed greatly reduces the fluctuation of the light intensity caused by the atmosphere. To obtain the required high sensitivity the laser output power is additionally made constant and stabilized by an electro-optical modulator. The present sensitivity is of the order of a few times 10(exp 5) OH per cm(exp 3) for an acquisition time of a minute and an absorption path length of only 1200 meters so that a folding of the optical path in a multireflection cell was possible leading to a lateral dimension of the cell of a few meters. This allows local measurements to be made. Tropospheric measurements have been carried out in 1991 resulting in the determination of OH diurnal variation at specific days in late summer. Comparison with model calculations have been made. Interferences are mainly due to SO2 absorption. The problem of OH self generation in the multireflection cell is of minor extent. This could be shown by using different experimental methods. The minimum-maximum signal to noise ratio is about 8 x 10(exp -4) for a single scan. Due to the small size of the absorption cell the realization of an open air laboratory is possible in which by use of an additional UV light source or by additional fluxes of trace gases the chemistry can be changed under controlled conditions allowing kinetic studies of tropospheric photochemistry to be made in open air.

Armerding, Wolfgang; Comes, Franz-Josef

1994-01-01

375

Absolute optical surface measurement with deflectometry  

NASA Astrophysics Data System (ADS)

Deflectometry utilises the deformation and displacement of a sample pattern after reflection from a test surface to infer the surface slopes. Differentiation of the measurement data leads to a curvature map, which is very useful for surface quality checks with sensitivity down to the nanometre range. Integration of the data allows reconstruction of the absolute surface shape, but the procedure is very error-prone because systematic errors may add up to large shape deviations. In addition, there are infinitely many combinations for slope and object distance that satisfy a given observation. One solution for this ambiguity is to include information on the object's distance. It must be known very accurately. Two laser pointers can be used for positioning the object, and we also show how a confocal chromatic distance sensor can be used to define a reference point on a smooth surface from which the integration can be started. The used integration algorithm works without symmetry constraints and is therefore suitable for free-form surfaces as well. Unlike null testing, deflectometry also determines radius of curvature (ROC) or focal lengths as a direct result of the 3D surface reconstruction. This is shown by the example of a 200 mm diameter telescope mirror, whose ROC measurements by coordinate measurement machine and deflectometry coincide to within 0.27 mm (or a sag error of 1.3?m). By the example of a diamond-turned off-axis parabolic mirror, we demonstrate that the figure measurement uncertainty comes close to a well-calibrated Fizeau interferometer.

Li, Wansong; Sandner, Marc; Gesierich, Achim; Burke, Jan

376

Orion Absolute Navigation System Progress and Challenge  

NASA Technical Reports Server (NTRS)

The absolute navigation design of NASA's Orion vehicle is described. It has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary onboard measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudo-range and delta-range, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, and cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.

Holt, Greg N.; D'Souza, Christopher

2012-01-01

377

Evaluation of the Absolute Regional Temperature Potential  

NASA Technical Reports Server (NTRS)

The Absolute Regional Temperature Potential (ARTP) is one of the few climate metrics that provides estimates of impacts at a sub-global scale. The ARTP presented here gives the time-dependent temperature response in four latitude bands (90-28degS, 28degS-28degN, 28-60degN and 60-90degN) as a function of emissions based on the forcing in those bands caused by the emissions. It is based on a large set of simulations performed with a single atmosphere-ocean climate model to derive regional forcing/response relationships. Here I evaluate the robustness of those relationships using the forcing/response portion of the ARTP to estimate regional temperature responses to the historic aerosol forcing in three independent climate models. These ARTP results are in good accord with the actual responses in those models. Nearly all ARTP estimates fall within +/-20%of the actual responses, though there are some exceptions for 90-28degS and the Arctic, and in the latter the ARTP may vary with forcing agent. However, for the tropics and the Northern Hemisphere mid-latitudes in particular, the +/-20% range appears to be roughly consistent with the 95% confidence interval. Land areas within these two bands respond 39-45% and 9-39% more than the latitude band as a whole. The ARTP, presented here in a slightly revised form, thus appears to provide a relatively robust estimate for the responses of large-scale latitude bands and land areas within those bands to inhomogeneous radiative forcing and thus potentially to emissions as well. Hence this metric could allow rapid evaluation of the effects of emissions policies at a finer scale than global metrics without requiring use of a full climate model.

Shindell, D. T.

2012-01-01

378

Absolute measurement of absorptance in DUV optics from laser-induced wavefront deformations  

NASA Astrophysics Data System (ADS)

A measurement system for quantitative determination of both surface and bulk contributions to the photo-thermal absorption in DUV optics was developed. It is based upon a Hartmann- Shack wavefront sensor with a sensitivity of ~?/10000 rms, accomplishing precise on-line monitoring of wavefront deformations of a collimated test laser beam transmitted perpendicular through the excimer laser-irradiated site of a cuboid sample. Caused by the temperature dependence of the refractive index as well as thermal expansion, the initially plane wavefront of the test laser is distorted into a cylindrical shape, with bending ends towards the surface. Sign and magnitude depend on index change and expansion. By comparison with thermal theory, this transient wavefront distortion yields a quantitative absolute measure of bulk and surface absorption losses in the sample. First results for fused silica are presented.

Mann, K.; Leinhos, U.; Sudradjat, J.; Schäfer, B.

2011-10-01

379

Absolute calorimetric calibration of low energy brachytherapy sources  

NASA Astrophysics Data System (ADS)

In the past decade there has been a dramatic increase in the use of permanent radioactive source implants in the treatment of prostate cancer. A small radioactive source encapsulated in a titanium shell is used in this type of treatment. The radioisotopes used are generally 125I or 103Pd. Both of these isotopes have relatively short half-lives, 59.4 days and 16.99 days, respectively, and have low-energy emissions and a low dose rate. These factors make these sources well suited for this application, but the calibration of these sources poses significant metrological challenges. The current standard calibration technique involves the measurement of ionization in air to determine the source air-kerma strength. While this has proved to be an improvement over previous techniques, the method has been shown to be metrologically impure and may not be the ideal means of calbrating these sources. Calorimetric methods have long been viewed to be the most fundamental means of determining source strength for a radiation source. This is because calorimetry provides a direct measurement of source energy. However, due to the low energy and low power of the sources described above, current calorimetric methods are inadequate. This thesis presents work oriented toward developing novel methods to provide direct and absolute measurements of source power for low-energy low dose rate brachytherapy sources. The method is the first use of an actively temperature-controlled radiation absorber using the electrical substitution method to determine total contained source power of these sources. The instrument described operates at cryogenic temperatures. The method employed provides a direct measurement of source power. The work presented here is focused upon building a metrological foundation upon which to establish power-based calibrations of clinical-strength sources. To that end instrument performance has been assessed for these source strengths. The intent is to establish the limits of the current instrument to direct further work in this field. It has been found that for sources with powers above approximately 2 muW the instrument is able to determine the source power in agreement to within less than 7% of what is expected based upon the current source strength standard. For lower power sources, the agreement is still within the uncertainty of the power measurement, but the calorimeter noise dominates. Thus, to provide absolute calibration of lower power sources additional measures must be taken. The conclusion of this thesis describes these measures and how they will improve the factors that limit the current instrument. The results of the work presented in this thesis establish the methodology of active radiometric calorimetey for the absolute calibration of radioactive sources. The method is an improvement over previous techniques in that there is no reliance upon the thermal properties of the materials used or the heat flow pathways on the source measurements. The initial work presented here will help to shape future refinements of this technique to allow lower power sources to be calibrated with high precision and high accuracy.

Stump, Kurt E.

380

A Global Least-Squares Fit for Absolute Zero  

Microsoft Academic Search

A simple, nonlinear least-squares method is described that permits gas thermometry data to be fitted directly to absolute zero. This nonlinear method can be implemented using Solver in Excel, and unlike other linear methods previously reported, it is statistically sound. The Excel macro SolverAid can be used to compute the error in absolute zero. The method can be applied simultaneously

Carl Salter

2003-01-01

381

Component mode synthesis for multibody systems with absolute coordinates  

Microsoft Academic Search

Abstract—In the present paper, the concept of the float- ing frame of reference is transformed to a description based on absolute coordinates. The equations are linearized for a certain configuration of the body based on a corotational strain tensor. Because of the transformation,to absolute coordinates, the mass matrix is constant and the stiffness matrix can be inverted efficiently. Pairs of

J. Gerstmayr

2007-01-01

382

Convective and absolute instabilities in non-Boussinesq mixed convection  

Microsoft Academic Search

The problem of non-Boussinesq mixed convection in a vertical channel formed by two differentially heated infinite plates is investigated and the complete convective\\/absolute instability boundary is computed for a wide range of physical parameters. A physical insight into the mechanisms causing instabilities is given. In particular, it is shown that the appearance of absolute instability is always dictated by a

Sergey A. Suslov

2007-01-01

383

Absolute Humidity and the Seasonality of Influenza (Invited)  

NASA Astrophysics Data System (ADS)

Much of the observed wintertime increase of mortality in temperate regions is attributed to seasonal influenza. A recent re-analysis of laboratory experiments indicates that absolute humidity strongly modulates the airborne survival and transmission of the influenza virus. Here we show that the onset of increased wintertime influenza-related mortality in the United States is associated with anomalously low absolute humidity levels during the prior weeks. We then use an epidemiological model, in which observed absolute humidity conditions temper influenza transmission rates, to successfully simulate the seasonal cycle of observed influenza-related mortality. The model results indicate that direct modulation of influenza transmissibility by absolute humidity alone is sufficient to produce this observed seasonality. These findings provide epidemiological support for the hypothesis that absolute humidity drives seasonal variations of influenza transmission in temperate regions. In addition, we show that variations of the basic and effective reproductive numbers for influenza, caused by seasonal changes in absolute humidity, are consistent with the general timing of pandemic influenza outbreaks observed for 2009 A/H1N1 in temperate regions. Indeed, absolute humidity conditions correctly identify the region of the United States vulnerable to a third, wintertime wave of pandemic influenza. These findings suggest that the timing of pandemic influenza outbreaks is controlled by a combination of absolute humidity conditions, levels of susceptibility and changes in population mixing and contact rates.

Shaman, J. L.; Pitzer, V.; Viboud, C.; Grenfell, B.; Goldstein, E.; Lipsitch, M.

2010-12-01

384

Determination of Absolute Zero Using a Computer-Based Laboratory  

ERIC Educational Resources Information Center

We present a simple computer-based laboratory experiment for evaluating absolute zero in degrees Celsius, which can be performed in college and undergraduate physical sciences laboratory courses. With a computer, absolute zero apparatus can help demonstrators or students to observe the relationship between temperature and pressure and use…

Amrani, D.

2007-01-01

385

Deformation modes in the finite element absolute nodal coordinate formulation  

Microsoft Academic Search

The objective of this study is to provide interpretation of the deformation modes in the finite element absolute nodal coordinate formulation using several strain definitions. In this finite element formulation, the nodal coordinates consist of absolute position coordinates and gradients that can be used to define a unique rotation and deformation fields within the element as well as at the

Hiroyuki Sugiyama; Johannes Gerstmayr; Ahmed A. Shabana

2006-01-01

386

Investigation of the absolute instability of currents in oceanic gyres  

Microsoft Academic Search

In the approximation of geometric optics, we study the absolute instability of currents in oceanic gyres. It is shown that absolute instability is observed in the case where the most unstable mode of wave motion is stationary. Our results qualitatively agree with the data of numerical experiments aimed at the simulation of the synoptic variability of large-scale oceanic gyres.

I. I. Karpatovich; G. K. Korotaev

2004-01-01

387

High precision absolute gravity gradiometry with atom interferometry  

Microsoft Academic Search

An absolute gravity gradiometer was demonstrated using atom interference techniques. This is the first realization of an gradiometer which uses an absolute standard for its calibration. A gravity gradiometer measures spatial changes in the gravitational field over a fixed baseline by making simultaneous acceleration measurements with two spatially separate accelerometers. The gradiometer has a differential sensitivity of 4 x 10-9

Jeffrey Michael McGuirk

2002-01-01

388

Synthesis and absolute stereochemistry of the bicyclic goniofupyranone core  

NASA Astrophysics Data System (ADS)

A bicyclic goniofupyranone core was synthesized from argentilactone using epoxide as an intermediate. The absolute stereochemistry of all asymmetric centers of a compound possessing the 2,6-dioxabicyclo [3.2.1]-octan-3-one moiety were unambiguously determined directly from X-ray data for the first time. Additionally, the absolute stereochemistry of the major epoxide was reported.

Alves, Ricardo Justino; Barros, Olga Soares do Rego; Kato, Lucilia; Martins, Felipe Terra; de Oliveira, Cecilia Maria Alves

2013-03-01

389

Testing spherical surfaces: a fast, quasi-absolute technique  

Microsoft Academic Search

A technique for measuring the quality of spherical surfaces that provides a quasi-absolute result is presented. It requires only two measurement positions rather than the traditional method of absolute sphere measurement that requires three measurement positions. A measurement is taken with a mirror at the focus of the interferometer diverger lens and is subtracted from a measurement of the sphere

Katherine Creath; James C. Wyant

1992-01-01

390

Ridge forces, absolute plate motions, and the intraplate stress field  

Microsoft Academic Search

The study calculates torque poles for a variety of possible forces acting on the plates, including ridge push, slab pull, and collisional resistance. These poles are compared to the directions of the absolute plate motions. A strong correlation is found between ridge torque poles and the azimuth of absolute plate motions for the North American, South American, Pacific, Cocos, and

Randall M. Richardson

1992-01-01

391

A Global Least-Squares Fit for Absolute Zero  

NASA Astrophysics Data System (ADS)

A simple, nonlinear least-squares method is described that permits gas thermometry data to be fitted directly to absolute zero. This nonlinear method can be implemented using Solver in Excel, and unlike other linear methods previously reported, it is statistically sound. The Excel macro SolverAid can be used to compute the error in absolute zero. The method can be applied simultaneously to multiple sets of data, permitting a global value of absolute zero to be computed from different gas samples. Constant volume thermometry data for helium are used to illustrate the global fit to absolute zero using Solver in an Excel spreadsheet. The relationship between the global value of absolute zero and the values from the individual fits is analyzed.

Salter, Carl

2003-09-01

392

Absolute Abundance Measurements in Solar Flares  

NASA Astrophysics Data System (ADS)

We present measurements of elemental abundances in solar flares with EVE/SDO and EIS/Hinode. EVE observes both high temperature Fe emission lines Fe XV-XXIV and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (F). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is F=1.17+-0.22. Furthermore, we have compared the EVE measurements with corresponding flare observations of intermediate temperature S, Ar, Ca, and Fe emission lines taken with EIS. Our initial calculations also indicate a photospheric composition for these observations. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation in the non-flaring corona occurs.

Warren, Harry

2014-06-01

393

Measurements of Absolute Abundances in Solar Flares  

NASA Astrophysics Data System (ADS)

We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory. EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (f). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is f = 1.17 ± 0.22. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation occurs.

Warren, Harry P.

2014-05-01

394

Development of a graphite probe calorimeter for absolute clinical dosimetry  

SciTech Connect

The aim of this work is to present the numerical design optimization, construction, and experimental proof of concept of a graphite probe calorimeter (GPC) conceived for dose measurement in the clinical environment (U.S. provisional patent 61/652,540). A finite element method (FEM) based numerical heat transfer study was conducted using a commercial software package to explore the feasibility of the GPC and to optimize the shape, dimensions, and materials used in its design. A functioning prototype was constructed inhouse and used to perform dose to water measurements under a 6 MV photon beam at 400 and 1000 MU/min, in a thermally insulated water phantom. Heat loss correction factors were determined using FEM analysis while the radiation field perturbation and the graphite to water absorbed dose conversion factors were calculated using Monte Carlo simulations. The difference in the average measured dose to water for the 400 and 1000 MU/min runs using the TG-51 protocol and the GPC was 0.2% and 1.2%, respectively. Heat loss correction factors ranged from 1.001 to 1.002, while the product of the perturbation and dose conversion factors was calculated to be 1.130. The combined relative uncertainty was estimated to be 1.4%, with the largest contributors being the specific heat capacity of the graphite (type B, 0.8%) and the reproducibility, defined as the standard deviation of the mean measured dose (type A, 0.6%). By establishing the feasibility of using the GPC as a practical clinical absolute photon dosimeter, this work lays the foundation for further device enhancements, including the development of an isothermal mode of operation and an overall miniaturization, making it potentially suitable for use in small and composite radiation fields. It is anticipated that, through the incorporation of isothermal stabilization provided by temperature controllers, a subpercent overall uncertainty will be achieved.

Renaud, James; Seuntjens, Jan; Sarfehnia, Arman [Medical Physics Unit, McGill University, Montreal, Quebec H3G 1A4 (Canada); Marchington, David [Ionizing Radiation Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)

2013-02-15

395

Oxygen potential measurements of Cm0.09Pu0.91O2-x by EMF method  

NASA Astrophysics Data System (ADS)

The dependence of the oxygen potentials on oxygen nonstoichiometry (x) and temperature of Cm0.09Pu0.91O2-x was measured by electromotive force (EMF) measurements. The galvanic cell type is shown: (Pt) air | Zr(Ca)O2-x | Cm0.09Pu0.91O2-x (Pt). The coulomb titration has been made for the sample at the intervals of 40 K between 1173 and 1333 K over the x range of 0.018 <= x <= 0.053. The oxygen potentials decreased gradually from -31.02 to -117.48 kJmol-1 with increasing x from 0.018 to 0.045, and more rapidly decreased from -117.48 to -283.74 kJmol-1 up to 0.053. The temperature dependence of the oxygen potentials was also measured between 1173 and 1333 K for several constant x values. The temperature dependences exhibited the smooth curves over the x and temperature ranges concerned. Systematic comparison of the oxygen potentials between Cm0.09Pu0.91O2-x and those published for CmO2 -x and Am-containing oxides was also made. The oxygen potential of Cm09Pu0.91O2-x at the equimolar ratio of Cm3+/Cm4+ was higher than those of AmyPu1-yO2-x at the equimolar ratio of Am3+/Am4+ by approximately 150 kJmol-1 when the Pu valence was assumed to be +4 in both oxides.

Otobe, H.; Akabori, M.; Arai, Y.

2010-03-01

396

Absolute Antenna Calibration at the US National Geodetic Survey  

NASA Astrophysics Data System (ADS)

Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood. One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns. For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software. Determination of antenna phase center behavior is known as "antenna calibration". Since 1994, NGS has computed relative antenna calibrations for more than 350 antennas. In recent years, the geodetic community has moved to absolute calibrations - the IGS adopted absolute antenna phase center calibrations in 2006 for use in their orbit and clock products, and NGS's CORS group began using absolute antenna calibration upon the release of the new CORS coordinates in IGS08 epoch 2005.00 and NAD 83(2011,MA11,PA11) epoch 2010.00. Although NGS relative calibrations can be and have been converted to absolute, it is considered best practice to independently measure phase center characteristics in an absolute sense. Consequently, NGS has developed and operates an absolute calibration system. These absolute antenna calibrations accommodate the demand for greater accuracy and for 2-dimensional (elevation and azimuth) parameterization. NGS will continue to provide calibration values via the NGS web site www.ngs.noaa.gov/ANTCAL, and will publish calibrations in the ANTEX format as well as the legacy ANTINFO format. The NGS absolute system is located in Corbin, Virginia, and uses field measurements and actual GNSS satellite signals to quantitatively determine the carrier phase advance/delay introduced by the antenna element. NGS is interested in providing calibrations for a wide variety of dual-frequency, geodetic-grade antennas, from types in use at IGS and CORS reference stations to rover antennas not normally seen in those networks. In this presentation, we describe the NGS absolute calibration facility, and discuss the observation models and strategy used to generate NGS absolute calibrations. We also demonstrate that NGS absolute phase center variation (PCV) patterns are consistent with published values determined by other absolute antenna calibration facilities.

Mader, G. L.; Bilich, A. L.

2012-12-01

397

Incorrect Weighting of Absolute Performance in Self-Assessment  

NASA Astrophysics Data System (ADS)

Students spend much of their life in an attempt to assess their aptitude for numerous tasks. For example, they expend a great deal of effort to determine their academic standing given a distribution of grades. This research finds that students use their absolute performance, or percentage correct as a yardstick for their self-assessment, even when relative standing is much more informative. An experiment shows that this reliance on absolute performance for self-evaluation causes a misallocation of time and financial resources. Reasons for this inappropriate responsiveness to absolute performance are explored.

Jeffrey, Scott A.; Cozzarin, Brian

398

Direct comparisons between absolute and relative geomagnetic paleointensities: Absolute calibration of a relative paleointensity stack  

NASA Astrophysics Data System (ADS)

Absolute geomagnetic paleointensities (APIs) have been estimated from igneous rocks, while relative paleomagnetic intensities (RPIs) have been reported from sediment cores. These two datasets have been treated separately, as correlations between APIs and RPIs are difficult on account of age uncertainties. High-resolution RPI stacks have been constructed from globally distributed sediment cores with high sedimentation rates. Previous studies often assumed that the RPI stacks have a linear relationship with geomagnetic axial dipole moments, and calibrated the RPI values to API values. However, the assumption of a linear relationship between APIs and RPIs has not been evaluated. Also, a quantitative calibration method for the RPI is lacking. We present a procedure for directly comparing API and RPI stacks, thus allowing reliable calibrations of RPIs. Direct comparisons between APIs and RPIs were conducted with virtually no associated age errors using both tephrochronologic correlations and RPI minima. Using the stratigraphic positions of tephra layers in oxygen isotope stratigraphic records, we directly compared the RPIs and APIs reported from welded tuffs contemporaneously extruded with the tephra layers. In addition, RPI minima during geomagnetic reversals and excursions were compared with APIs corresponding to the reversals and excursions. The comparison of APIs and RPIs at these exact points allowed a reliable calibration of the RPI values. We applied this direct comparison procedure to the global RPI stack PISO-1500. For six independent calibration points, virtual axial dipole moments (VADMs) from the corresponding APIs and RPIs of the PISO-1500 stack showed a near-linear relationship. On the basis of the linear relationship, RPIs of the stack were successfully calibrated to the VADMs. The direct comparison procedure provides an absolute calibration method that will contribute to the recovery of temporal variations and distributions of geomagnetic axial dipole moments from RPI stacks for the past several million years.

Mochizuki, N.; Yamamoto, Y.; Hatakeyama, T.; Shibuya, H.

2013-12-01

399

Potential vorticity estimates of absolute velocities on the Ross Sea shelf  

NASA Astrophysics Data System (ADS)

We analyze absolute velocities on the continental shelf off Cape Adare, in the western sector of the Ross Sea (Antarctica). Such a velocity field is here inferred by using a novel inverse method of absolute velocity determination, namely the tracer PV method, related to potential vorticities of temperature and salinity. This theoretical choice allows us to directly use in situ temperature and salinity data. Moreover, it avoids high-order derivatives, which can give large uncertainties that affect estimates made using previous approaches. The tracer PV method also allows us to separately estimate the steady and non-diffusive component and the unsteady and diffusive components of the flow. The western sector of the Ross Sea is characterized by a surface layer of Antarctic Surface Water over layers of Low Salinity Shelf Water and High Salinity Shelf Water, flowing northward with average velocities ˜6-7 cm/s. At ˜200 m depth an intrusion of warmer and saltier Circumpolar Deep Water is also evident in our data. The steady absolute velocities are in good agreement with those obtained from the classical Margules equation, in particular regarding the northward flux of the High Salinity Shelf Water. Furthermore, velocities due to diffusive processes and mesoscale activity are discussed. Finally, a steady "thermal" approximation is discussed; it allows for a qualitative check of the results by means of temperature horizontal sections only.

Falcini, Federico; Iudicone, Daniele; Salusti, Ettore

2009-03-01

400

Ge/Si(001) heterostructures with dense arrays of Ge quantum dots: morphology, defects, photo-emf spectra and terahertz conductivity  

PubMed Central

Issues of Ge hut cluster array formation and growth at low temperatures on the Ge/Si(001) wetting layer are discussed on the basis of explorations performed by high resolution STM and in-situ RHEED. Dynamics of the RHEED patterns in the process of Ge hut array formation is investigated at low and high temperatures of Ge deposition. Different dynamics of RHEED patterns during the deposition of Ge atoms in different growth modes is observed, which reflects the difference in adatom mobility and their ‘condensation’ fluxes from Ge 2D gas on the surface for different modes, which in turn control the nucleation rates and densities of Ge clusters. Data of HRTEM studies of multilayer Ge/Si heterostructures are presented with the focus on low-temperature formation of perfect films. Heteroepitaxial Si p–i–n-diodes with multilayer stacks of Ge/Si(001) quantum dot dense arrays built in intrinsic domains have been investigated and found to exhibit the photo-emf in a wide spectral range from 0.8 to 5 ?m. An effect of wide-band irradiation by infrared light on the photo-emf spectra has been observed. Photo-emf in different spectral ranges has been found to be differently affected by the wide-band irradiation. A significant increase in photo-emf is observed in the fundamental absorption range under the wide-band irradiation. The observed phenomena are explained in terms of positive and neutral charge states of the quantum dot layers and the Coulomb potential of the quantum dot ensemble. A new design of quantum dot infrared photodetectors is proposed. By using a coherent source spectrometer, first measurements of terahertz dynamical conductivity (absorptivity) spectra of Ge/Si(001) heterostructures were performed at frequencies ranged from 0.3 to 1.2 THz in the temperature interval from 300 to 5 K. The effective dynamical conductivity of the heterostructures with Ge quantum dots has been discovered to be significantly higher than that of the structure with the same amount of bulk germanium (not organized in an array of quantum dots). The excess conductivity is not observed in the structures with the Ge coverage less than 8 Å. When a Ge/Si(001) sample is cooled down the conductivity of the heterostructure decreases.

2012-01-01

401

Ge/Si(001) heterostructures with dense arrays of Ge quantum dots: morphology, defects, photo-emf spectra and terahertz conductivity.  

PubMed

: Issues of Ge hut cluster array formation and growth at low temperatures on the Ge/Si(001) wetting layer are discussed on the basis of explorations performed by high resolution STM and in-situ RHEED. Dynamics of the RHEED patterns in the process of Ge hut array formation is investigated at low and high temperatures of Ge deposition. Different dynamics of RHEED patterns during the deposition of Ge atoms in different growth modes is observed, which reflects the difference in adatom mobility and their 'condensation' fluxes from Ge 2D gas on the surface for different modes, which in turn control the nucleation rates and densities of Ge clusters. Data of HRTEM studies of multilayer Ge/Si heterostructures are presented with the focus on low-temperature formation of perfect films.Heteroepitaxial Si p-i-n-diodes with multilayer stacks of Ge/Si(001) quantum dot dense arrays built in intrinsic domains have been investigated and found to exhibit the photo-emf in a wide spectral range from 0.8 to 5 ?m. An effect of wide-band irradiation by infrared light on the photo-emf spectra has been observed. Photo-emf in different spectral ranges has been found to be differently affected by the wide-band irradiation. A significant increase in photo-emf is observed in the fundamental absorption range under the wide-band irradiation. The observed phenomena are explained in terms of positive and neutral charge states of the quantum dot layers and the Coulomb potential of the quantum dot ensemble. A new design of quantum dot infrared photodetectors is proposed.By using a coherent source spectrometer, first measurements of terahertz dynamical conductivity (absorptivity) spectra of Ge/Si(001) heterostructures were performed at frequencies ranged from 0.3 to 1.2 THz in the temperature interval from 300 to 5 K. The effective dynamical conductivity of the heterostructures with Ge quantum dots has been discovered to be significantly higher than that of the structure with the same amount of bulk germanium (not organized in an array of quantum dots). The excess conductivity is not observed in the structures with the Ge coverage less than 8 Å. When a Ge/Si(001) sample is cooled down the conductivity of the heterostructure decreases. PMID:22824144

Yuryev, Vladimir A; Arapkina, Larisa V; Storozhevykh, Mikhail S; Chapnin, Valery A; Chizh, Kirill V; Uvarov, Oleg V; Kalinushkin, Victor P; Zhukova, Elena S; Prokhorov, Anatoly S; Spektor, Igor E; Gorshunov, Boris P

2012-01-01

402

Determination of standard molar Gibbs free energy of formation of Bi 2O 3 over a wide temperature range by EMF method  

Microsoft Academic Search

The EMF of the following galvanic cells (I)W,Bi,Bi2O3|CSZ|O2(1atm),RuO2,Pt(II)W,Bi,Bi2O3|CSZ|O2(1atm),Ptwere measured over a wide range of temperature (572 to 1127) K. With O2 (1 atm) reference and RuO2 as the electrode material with Pt as electrical lead, measurements were possible at temperatures close to the melting temperature of Bi. Standard Gibbs free energies of formation, ?fG0m of Bi2O3(s) (both ? and ?

Rajesh Ganesan; T. Gnanasekaran; Raman S. Srinivasa

2003-01-01

403

Study of thermodynamic properties of quaternary mixture RbCl + Rb 2SO 4 + CH 3OH + H 2O by EMF measurement at 298.15 K  

Microsoft Academic Search

The electromotive force (EMF) measurements of the cell: Rb-ion selective electrode (ISE)\\/RbCl (mA), Rb2SO4 (mB), CH3OH (X), H2O (1?X)\\/AgAgCl with X=10wt.% on the quaternary system RbCl+Rb2SO4+CH3OH+H2O were carried out at 298.15K and over total ionic strengths from 0.0050molkg?1 up to near saturated concentration 2.5000molkg?1. The Rb-ISE and AgAgCl electrodes used in this work were prepared in our laboratory and exhibited

Zhang-Jun; Gao Shi-Yang; Xia Shu-Ping; Yao-Yan

2004-01-01

404

Absolute angular calibration of a submarine km3 neutrino telescope  

NASA Astrophysics Data System (ADS)

A requirement for neutrino telescope is the ability to resolve point sources of neutrinos. In order to understand its resolving power a way to perform absolute angular calibration with muons is required. Muons produced by cosmic rays in the atmosphere offer an abundant calibration source. By covering a surface vessel with 200 modules of 5 m2 plastic scintillator a surface air shower array can be set up. Running this array in coincidence with a deep-sea km3 size neutrino detector, where the coincidence is defined by the absolute clock timing stamp for each event, would allow absolute angular calibration to be performed. Monte Carlo results simulating the absolute angular calibration of the km3 size neutrino detector will be presented. Future work and direction will be discussed.

Anassontzis, E.; Liubarsky, I.; Psallidas, A.; Resvanis, L. K.; Lenis, D.; Rapidis, P. A.

2011-01-01

405

Stability and Error Analysis for Absolutely Calibrated Geodetic GPS Receivers.  

National Technical Information Service (NTIS)

The absence of absolute calibration data for geodetic-quality Global Positioning System (GPS) receivers and their associated equipment has limited the application of these instruments for time transfer. We have conducted a series of tests in order to cali...

E. Powers J. Plumb J. White K. Larson R. Beard

2002-01-01

406

Absolute pitch in infant auditory learning: evidence for developmental reorganization.  

PubMed

To what extent do infants represent the absolute pitches of complex auditory stimuli? Two experiments with 8-month-old infants examined the use of absolute and relative pitch cues in a tone-sequence statistical learning task. The results suggest that, given unsegmented stimuli that do not conform to the rules of musical composition, infants are more likely to track patterns of absolute pitches than of relative pitches. A 3rd experiment tested adults with or without musical training on the same statistical learning tasks used in the infant experiments. Unlike the infants, adult listeners relied primarily on relative pitch cues. These results suggest a shift from an initial focus on absolute pitch to the eventual dominance of relative pitch, which, it is argued, is more useful for both music and speech processing. PMID:11206435

Saffran, J R; Griepentrog, G J

2001-01-01

407

JILA (Joint Institute for Laboratory Astrophysics) Portable Absolute Gravity Apparatus.  

National Technical Information Service (NTIS)

We have developed a new and highly portable absolute gravity apparatus based on the principles of free-fall laser interferometry. A primary concern over the past several years has been the detection, understanding, and elimination of systematic errors. In...

J. E. Faller Y. G. Guo J. Gschwind T. M. Niebauer R. L. Rinker

1983-01-01

408

Multiple Sensors for Absolute Measurement of Aerobraking Spacecraft State Estimation  

NASA Astrophysics Data System (ADS)

Prior methods to determine the spacecraft state estimation for aerobraking have been radiometric tracking data and IMU measurement. We propose a novel method for real-time absolute measurement of full state estimation based on multiple sensors.

Pigneur, B.; Ariyur, K. B.

2014-06-01

409

Absolute Magnitudes of Be Stars Based on Hipparcos Parallaxes  

NASA Astrophysics Data System (ADS)

The absolute visual magnitudes of 457 Be stars are determined from Hipparcos parallaxes, subsequently the mean absolute visual magnitudes of Be stars for luminosity classes III, IV and V are obtained. The new Mv calibration is compared with existing calibrations. It is found that Be stars are generally brighter than B stars of the corresponding spectral types, and that there is no direct correlation between absolute magnitudes and the stellar rotational velocity, these results are in agreement with some earlier results. A new and interesting result is that there is no direct correlation between near infrared excess and absolute visual magnitudes for Be stars. Moreover, possible biases, such as the Malmquist bias and the Lutz Kelker bias, are also discussed.

Zhang, P.; Liu, C. Q.; Chen, P. S.

2006-12-01

410

Structural Health Monitoring of Strategically Tuned Absolutely Resilient Structures (STARS).  

National Technical Information Service (NTIS)

Strategically Tuned Absolutely Resilient Structures (STARS) are being designed to store potential energy in the form of elastic deformation that can be released in a controlled fashion as work or kinetic energy. This paper outlines steps being taken to mo...

J. A. Gilbert S. A. Marotta T. K. Ooi

2010-01-01

411

Technique of Absolute Efficiency Determination for gamma Radiation Semiconductor Detectors.  

National Technical Information Service (NTIS)

Simple technique is suggested to determine the absolute efficiency (E) of semiconductor detectors (SCD) which employs low-intensity neutron sources wide spread in scientific laboratories. The technique is based on using radioactive nuclide gamma radiation...

Vo Dak Bang Chan Dyk Tkhiep Chan Daj Ngiep Fan Tkhu Khyong, S. Gehrbish

1983-01-01

412

Convective and absolute instabilities in non-Boussinesq mixed convection  

Microsoft Academic Search

The problem of non-Boussinesq mixed convection in a vertical channel formed by two differentially heated infinite plates is\\u000a investigated and the complete convective\\/absolute instability boundary is computed for a wide range of physical parameters.\\u000a A physical insight into the mechanisms causing instabilities is given. In particular, it is shown that the appearance of absolute\\u000a instability is always dictated by a

Sergey A. Suslov

2007-01-01

413

Absolute detection efficiencies of a microchannel plate detector for ions  

Microsoft Academic Search

Absolute single-particle detection efficiencies of a microchannel plate (MCP) detector were determined by photo-ionization of atoms or molecules. The ionized heavy particles were detected in coincidence with the resulting electrons. This method allows the determination of detection efficiencies without a knowledge of the absolute event rates. We obtained the detection efficiencies for the ions H2+, D2+, HD+, H+, D+ and

B. Brehm; J. Grosser; T. Ruscheinski; M. Zimmer

1995-01-01

414

Low-complex BPSK demodulation using absolute comparison  

Microsoft Academic Search

A new CMOS-friendly BPSK demodulation method is presented to reduce circuit complexity without degrading performance. The proposed method compares absolute values of in-phase and quadrature-phase signals to select the larger one to be converted to a digital value. The digital value is reversed when the inversion case is detected. A simple double-balanced mixer and an efficient absolute current comparison block

YoungJoo Lee; Goeun Lim; In-Cheol Park

2010-01-01

415

Absolute calibration of photodetectors: photocurrent multiplication versus photocurrent subtraction.  

PubMed

We report testing of the new absolute method of photodetector calibration based on the difference-signal measurement for two-mode squeezed vacuum by comparison with the traditional absolute method based on coincidence counting. Using low-gain parametric downconversion, we have measured the quantum efficiency of a counting detector by both methods. The difference-signal method was adapted for the counting detectors by taking into account the dead-time effect. PMID:21499346

Agafonov, I N; Chekhova, M V; Iskhakov, T S; Penin, A N; Rytikov, G O; Shcherbina, O A

2011-04-15

416

Absolute and Convective Instability of a Liquid Jet in Microgravity  

NASA Technical Reports Server (NTRS)

The transition from convective to absolute instability is observed in the 2.2 second drop tower of the NASA Lewis Research Center. In convective instability the disturbance grows spatially as it is convected downstream. In absolute instability the disturbance propagates both downstream and upstream, and manifests itself as an expanding sphere. The transition Reynolds numbers are determined for two different Weber numbers by use of Glycerin and a Silicone oil. Preliminary comparisons with theory are made.

Lin, Sung P.; Vihinen, I.; Honohan, A.; Hudman, Michael D.

1996-01-01

417

Near-Infrared Absolute Photometric Imaging of the Uranian System  

Microsoft Academic Search

We report the first multifilter set of absolutely calibrated near-infrared images of Uranus, its rings, and three major satellites—Titania, Ariel, and Miranda. Along with imagery utilizing the canonical K filter bandpass (effective wavelength 2.20 ?m), absolutely calibrated images of the uranian system are presented for the first time for three additional filter bandpasses: J (1.27 ?m), H (1.62 ?m), and

Kevin H. Baines; Padmavati A. Yanamandra-Fisher; Larry A. Lebofsky; Thomas W. Momary; William Golisch; Charles Kaminski; Walter J. Wild

1998-01-01

418

Near-Infrared Absolute Photometric Imaging of the Uranian System  

Microsoft Academic Search

We report the first multifilter set of absolutely calibrated near-infrared images of Uranus, its rings, and three major satellites-Titania, Ariel, and Miranda. Along with imagery utilizing the canonical K filter bandpass (effective wavelength 2.20 mum), absolutely calibrated images of the uranian system are presented for the first time for three additional filter bandpasses: J (1.27 mum), H (1.62 mum), and

Kevin H. Baines; Padmavati A. Yanamandra-Fisher; Larry A. Lebofsky; Thomas W. Momary; William Golisch; Charles Kaminski; Walter J. Wild

1998-01-01

419

Wf/pc SV Obs: Absolute Flux Standards-Revised  

NASA Astrophysics Data System (ADS)

The purpose of this calibration is to obtain data on flux standards through WF/PC. These stars are 9 - 14 magnitude. This proposal replaces previous proposals ABSOLUTE UV CALIBRATION (1322) and ABSOLUTE FLUX STANDARDS (1331). Two brighter target stars have been added. Pick the brightest star available in RA range. Exposure times for all stars have been updated, and F889N has been added to some stars, as it proved too faint to calibrate in Omega Cen.

Westphal, J.

1990-07-01

420

Absolute measurement of neutron cross sections. Progress report  

SciTech Connect

The procedures and status of the absolute measurement of the neutron capture cross sections for /sup 115/In and /sup 232/Th are described. Work on the /sup 239/Pu fission fragment anisotropy and absolute measurement of the fast neutron fission cross section for /sup 233/U are briefly described. Progress in establishing the 14 MeV neutron measurements at the facility are discussed. (WHK)

Knoll, G.F.

1981-02-19

421

Structure elucidation and absolute stereochemistry of isomeric monoterpene chromane esters.  

PubMed

Six novel monoterpene chromane esters were isolated from the aerial parts of Peperomia obtusifolia (Piperaceae) using chiral chromatography. This is the first time that chiral chromane esters of this kind, ones with a tethered chiral terpene, have been isolated in nature. Due to their structural features, it is not currently possible to assess directly their absolute stereochemistry using any of the standard classical approaches, such as X-ray crystallography, NMR, optical rotation, or electronic circular dichroism (ECD). Herein we report the absolute configuration of these molecules, involving four chiral centers, using vibrational circular dichroism (VCD) and density functional theory (DFT) (B3LYP/6-31G*) calculations. This work further reinforces the capability of VCD to determine unambiguously the absolute configuration of structurally complex molecules in solution, without crystallization or derivatization, and demonstrates the sensitivity of VCD to specify the absolute configuration for just one among a number of chiral centers. We also demonstrate the sufficiency of using the so-called inexpensive basis set 6-31G* compared to the triple-? basis set TZVP for absolute configuration analysis of larger molecules using VCD. Overall, this work extends our knowledge of secondary metabolites in plants and provides a straightforward way to determine the absolute configuration of complex natural products involving a chiral parent moiety combined with a chiral terpene adduct. PMID:21401052

Batista, João M; Batista, Andrea N L; Mota, Jonas S; Cass, Quezia B; Kato, Massuo J; Bolzani, Vanderlan S; Freedman, Teresa B; López, Silvia N; Furlan, Maysa; Nafie, Laurence A

2011-04-15

422

RELATIVE VERSUS ABSOLUTE STIMULUS CONTROL IN THE TEMPORAL BISECTION TASK  

PubMed Central

When subjects learn to associate two sample durations with two comparison keys, do they learn to associate the keys with the short and long samples (relational hypothesis), or with the specific sample durations (absolute hypothesis)? We exposed 16 pigeons to an ABA design in which phases A and B corresponded to tasks using samples of 1 s and 4 s, or 4 s and 16 s. Across phases, we varied the mapping between the samples and the keys. For group Relative, short and long samples were always associated with the same keys (e.g., Phase A: ‘1s? Left, 4s? Right'; Phase B: ‘4s? Left, 16s? Right'); for group Absolute, the 4-s sample was associated always with the same key (e.g., Phase A: ‘1s? Left, 4s? Right'; Phase B: ‘16s? Left, 4s? Right’). If temporal control is relational, group Relative should learn the new task faster than group Absolute, but if temporal control is absolute, the opposite should occur. We compared the results with the predictions of the Learning-to-Time (LeT) model, which accounts for temporal discrimination in terms of absolute stimulus control and stimulus generalization. The acquisition curves of the two groups were generally consistent with LeT and therefore more consistent with the absolute than the relative hypothesis.

Pinheiro de Carvalho, Marilia; Machado, Armando

2012-01-01

423

Revisiting absolute and relative judgments in the WITNESS model.  

PubMed

The WITNESS model (Clark in Applied Cognitive Psychology 17:629-654, 2003) provides a theoretical framework with which to investigate the factors that contribute to eyewitness identification decisions. One key factor involves the contributions of absolute versus relative judgments. An absolute contribution is determined by the degree of match between an individual lineup member and memory for the perpetrator; a relative contribution involves the degree to which the best-matching lineup member is a better match to memory than the remaining lineup members. In WITNESS, the proportional contributions of relative versus absolute judgments are governed by the values of the decision weight parameters. We conducted an exploration of the WITNESS model's parameter space to determine the identifiability of these relative/absolute decision weight parameters, and compared the results to a restricted version of the model that does not vary the decision weight parameters. This exploration revealed that the decision weights in WITNESS are difficult to identify: Data often can be fit equally well by setting the decision weights to nearly any value and compensating with a criterion adjustment. Clark, Erickson, and Breneman (Law and Human Behavior 35:364-380, 2011) claimed to demonstrate a theoretical basis for the superiority of lineup decisions that are based on absolute contributions, but the relationship between the decision weights and the criterion weakens this claim. These findings necessitate reconsidering the role of the relative/absolute judgment distinction in eyewitness decision making. PMID:23943556

Fife, Dustin; Perry, Colton; Gronlund, Scott D

2014-04-01

424

Thermal properties measurements in biodiesel oils using photothermal techniques  

NASA Astrophysics Data System (ADS)

In this Letter, thermal lens and open cell photoacoustic techniques are used to measure the thermal properties of biodiesel oils. The absolute values of the thermal effusivity, thermal diffusivity, thermal conductivity and the temperature coefficient of the refractive index were determined for samples obtained from soy, castor bean, sunflower and turnip. The results suggest that the employed techniques may be useful as complementary methods for biodiesel certification.

Castro, M. P. P.; Andrade, A. A.; Franco, R. W. A.; Miranda, P. C. M. L.; Sthel, M.; Vargas, H.; Constantino, R.; Baesso, M. L.

2005-08-01

425

Banach Ideals of Operators Defined by Classes of Cone Absolutely Summing and Strongly Majorizing Mappings.  

National Technical Information Service (NTIS)

The ideals of absolutely delta summing and dual absolutely delta summing mappings are characterized as 'quotients' by continuous linear mappings of certain classes of cone absolutely summing and strongly majorizing mappings respectively. The ideals of del...

J. Swart J. J. Conradie

1979-01-01

426

Electrochemical Studies and Absolute Work Function Measurements in Gas Ambient  

NASA Astrophysics Data System (ADS)

A simple, direct and convenient method for making absolute work function measurements in gas ambient is presented. The method consists of making measurements with a kelvin probe that has been calibrated using the clean solution surface of an electrochemical half-cell. It is shown here that the outer potential of the half-cell solution surface is constant, reliable and readily reproducible. This makes the method possible. This method for making absolute work function measurements in gas ambient requires a knowledge of the absolute work function of the half-cell. This is related to the absolute half-cell potential. The absolute half-cell potential is discussed. Previous measurements of its value disagree and are controversial. The work function of clean Hg in gas ambient is studied. Using the work function of mercury as measured in vacuum as a reference, the absolute half-cell potential for the SCE (saturated calomel electrode) is measured to be E_{rm SCE}(abs) = -4.670 +/-.027 V. A carbon sample was also used as a reference to measure the SCE. The carbon sample's work function was measured in vacuum photoelectrically immediately before comparing to the SCE in gas ambient. Using this method, the absolute half-cell potential for the SCE was measured to be E _{rm SCE}(abs) = -4.635 +/-.050 V. Measurements on gold show that its work function decreases rapidly when removed from vacuum and that it is unstable in air. A study of the chi (chi) potential of solution-gas ambient surface (electrostatic potential difference across the interphase) is included. It was found that chi is constant for many different electrolyte solutions at varying concentrations. This allows liquid junction potentials to be measured. Also, an acoustically modulated kelvin probe was designed and built for use in gas ambient on liquid and solid surfaces.

Johnson, Kendall B.

427

Absolute irradiance of the Moon for on-orbit calibration  

USGS Publications Warehouse

The recognized need for on-orbit calibration of remote sensing imaging instruments drives the ROLO project effort to characterize the Moon for use as an absolute radiance source. For over 5 years the ground-based ROLO telescopes have acquired spatially-resolved lunar images in 23 VNIR (Moon diameter ???500 pixels) and 9 SWIR (???250 pixels) passbands at phase angles within ??90 degrees. A numerical model for lunar irradiance has been developed which fits hundreds of ROLO images in each band, corrected for atmospheric extinction and calibrated to absolute radiance, then integrated to irradiance. The band-coupled extinction algorithm uses absorption spectra of several gases and aerosols derived from MODTRAN to fit time-dependent component abundances to nightly observations of standard stars. The absolute radiance scale is based upon independent telescopic measurements of the star Vega. The fitting process yields uncertainties in lunar relative irradiance over small ranges of phase angle and the full range of lunar libration well under 0.5%. A larger source of uncertainty enters in the absolute solar spectral irradiance, especially in the SWIR, where solar models disagree by up to 6%. Results of ROLO model direct comparisons to spacecraft observations demonstrate the ability of the technique to track sensor responsivity drifts to sub-percent precision. Intercomparisons among instruments provide key insights into both calibration issues and the absolute scale for lunar irradiance.

Stone, T. C.; Kieffer, H. H.

2002-01-01

428

Absolute Neutron Emission Measurement in Burning Plasma Experiments  

SciTech Connect

The absolute measurement of neutron emission rate from the whole plasma is a very important diagnostics as a fusion power monitor in fusion experimental devices with D-T or D-T operations. Here measurement techniques of time-resolved and time-integrated absolute neutron emission on the present tokamaks and ITER are reviewed. In the present tokamaks, fission chamber installed outside the vacuum vessel are very popular in the absolute neutron emission rate measurement. As well as conventional neutron monitors installed outside the vacuum vessel, in-vessel neutron monitors using micro fission chamber are proposed for the absolute neutron emission rate measurement in ITER. The neutron activation system provides time-integrated measurements of the total neutron yield with high accuracy by using well known neutron reaction cross sections, which is useful to maintain a robust measure of fusion energy production with stability and wide dynamic range. The calibration of the relation between the neutron emission rate in the whole plasma and the output of neutron monitor is the most important issue in the absolute neutron emission rate measurements. The calibration of the neutron detectors has been performed by moving a neutron source such as a {sup 252}Cf neutron or a small accelerator-based neutron generator. For the calibration in ITER, the neutron generator with neutron emission rate of 10{sup 11} s{sup -1} or stronger is required to obtain high accuracy.

Nishitani, Takeo; Ishikawa, Masao; Kondoh, Takashi; Kusama, Yoshinori [Japan Atomic Energy Agency, Naka, Ibaraki-ken, 311-0193 (Japan); Asai, Keisuke [Nagoya University, Chikusa-ku, Nagoya, 464-8603 (Japan); Sasao, Mmamiko [Tohoku University, Aoba-ku, Sendai, 980-8579 (Japan)

2008-03-12

429

Absolute Neutron Emission Measurement in Burning Plasma Experiments  

NASA Astrophysics Data System (ADS)

The absolute measurement of neutron emission rate from the whole plasma is a very important diagnostics as a fusion power monitor in fusion experimental devices with D-T or D-T operations. Here measurement techniques of time-resolved and time-integrated absolute neutron emission on the present tokamaks and ITER are reviewed. In the present tokamaks, fission chamber installed outside the vacuum vessel are very popular in the absolute neutron emission rate measurement. As well as conventional neutron monitors installed outside the vacuum vessel, in-vessel neutron monitors using micro fission chamber are proposed for the absolute neutron emission rate measurement in ITER. The neutron activation system provides time-integrated measurements of the total neutron yield with high accuracy by using well known neutron reaction cross sections, which is useful to maintain a robust measure of fusion energy production with stability and wide dynamic range. The calibration of the relation between the neutron emission rate in the whole plasma and the output of neutron monitor is the most important issue in the absolute neutron emission rate measurements. The calibration of the neutron detectors has been performed by moving a neutron source such as a 252Cf neutron or a small accelerator-based neutron generator. For the calibration in ITER, the neutron generator with neutron emission rate of 1011 s-1 or stronger is required to obtain high accuracy.

Nishitani, Takeo; Ishikawa, Masao; Kondoh, Takashi; Kusama, Yoshinori; Asai, Keisuke; Sasao, Mmamiko

2008-03-01

430

Absolute distance sensing by two laser optical interferometry.  

PubMed

We have developed a method for absolute distance sensing by two laser optical interferometry. A particularity of this technique is that a target distance is determined in absolute and is no longer limited to within an ambiguity range affecting usually multiple wavelength interferometers. We implemented the technique in a low-finesse Fabry-Pérot miniature fiber based interferometer. We used two diode lasers, both operating in the 1550 nm wavelength range. The wavelength difference is chosen to create a 25 ?m long periodic beating interferometric pattern allowing a nanometer precise position measurement but limited to within an ambiguity range of 25 ?m. The ambiguity is then eliminated by scanning one of the wavelengths over a small range (3.4 nm). We measured absolute distances in the sub-meter range and this with just few nanometer repeatability. PMID:24289429

Thurner, Klaus; Braun, Pierre-François; Karrai, Khaled

2013-11-01

431

System and method for calibrating a rotary absolute position sensor  

NASA Technical Reports Server (NTRS)

A system includes a rotary device, a rotary absolute position (RAP) sensor generating encoded pairs of voltage signals describing positional data of the rotary device, a host machine, and an algorithm. The algorithm calculates calibration parameters usable to determine an absolute position of the rotary device using the encoded pairs, and is adapted for linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters. A method of calibrating the RAP sensor includes measuring the rotary position as encoded pairs of voltage signals, linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters, and calculating an absolute position of the rotary device using the calibration parameters. The calibration parameters include a positive definite matrix (A) and a center point (q) of the ellipse. The voltage signals may include an encoded sine and cosine of a rotary angle of the rotary device.

Davis, Donald R. (Inventor); Permenter, Frank Noble (Inventor); Radford, Nicolaus A (Inventor)

2012-01-01

432

Absolute surface metrology by rotational averaging in oblique incidence interferometry.  

PubMed

A modified method for measuring the absolute figure of a large optical flat surface in synchrotron radiation by a small aperture interferometer is presented. The method consists of two procedures: the first step is oblique incidence measurement; the second is multiple rotating measurements. This simple method is described in terms of functions that are symmetric or antisymmetric with respect to reflections at the vertical axis. Absolute deviations of a large flat surface could be obtained when mirror antisymmetric errors are removed by N-position rotational averaging. Formulas are derived for measuring the absolute surface errors of a rectangle flat, and experiments on high-accuracy rectangle flats are performed to verify the method. Finally, uncertainty analysis is carried out in detail. PMID:24922410

Lin, Weihao; He, Yumei; Song, Li; Luo, Hongxin; Wang, Jie

2014-06-01

433

Absolute Coefficients and the Graphical Representation of Airfoil Characteristics  

NASA Technical Reports Server (NTRS)

It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil. The author notes that, on the whole, it appears that the use of natural absolute coefficients in a polar diagram is the logical method for presentation of airfoil characteristics, and that serious consideration should be given to the advisability of adopting this method in all countries, in order to advance uniformity and accuracy in the science of aeronautics.

Munk, Max

1921-01-01

434

Absolute distance sensing by two laser optical interferometry  

NASA Astrophysics Data System (ADS)

We have developed a method for absolute distance sensing by two laser optical interferometry. A particularity of this technique is that a target distance is determined in absolute and is no longer limited to within an ambiguity range affecting usually multiple wavelength interferometers. We implemented the technique in a low-finesse Fabry-Pérot miniature fiber based interferometer. We used two diode lasers, both operating in the 1550 nm wavelength range. The wavelength difference is chosen to create a 25 ? m long periodic beating interferometric pattern allowing a nanometer precise position measurement but limited to within an ambiguity range of 25 ? m. The ambiguity is then eliminated by scanning one of the wavelengths over a small range (3.4 nm). We measured absolute distances in the sub-meter range and this with just few nanometer repeatability.

Thurner, Klaus; Braun, Pierre-François; Karrai, Khaled

2013-11-01

435

Neural sensitivity to absolute and relative anticipated reward in adolescents.  

PubMed

Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity. PMID:23544046

Vaidya, Jatin G; Knutson, Brian; O'Leary, Daniel S; Block, Robert I; Magnotta, Vincent

2013-01-01

436

Neural Sensitivity to Absolute and Relative Anticipated Reward in Adolescents  

PubMed Central

Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity.

Vaidya, Jatin G.; Knutson, Brian; O'Leary, Daniel S.; Block, Robert I.; Magnotta, Vincent

2013-01-01

437

Absolute exponential stability analysis of delayed neural networks [rapid communication  

NASA Astrophysics Data System (ADS)

In this Letter, we investigate the absolute exponential stability of a class of delayed neural networks. A new sufficient condition ensuring existence and uniqueness of equilibrium and its absolute exponential stability is derived. When the neural network model is simplified to one without delays, the present condition is reduced to the well-known additive diagonal stability condition of the interconnection weight matrix, which was previously established and proven to be general enough for ensuring stability of neural networks without delays in the literature. Thus, our condition generalizes the additive diagonal stability condition to the case of neural networks with delays.

Lu, Hongtao

2005-03-01

438

DETERMINING THE ABSOLUTE ASTROMETRIC ERROR IN CHANDRA SOURCE CATALOG POSITIONS  

SciTech Connect

Although relative errors can readily be calculated, the absolute astrometric accuracy of the source positions in the Chandra Source Catalog (CSC), version 1.0, is a priori unknown. However, the cross-match with stellar objects from the Sloan Digital Sky Survey offers the opportunity to compare the apparent separations of the cross-matched pairs with the formally calculated errors. The analysis of these data allowed us to derive a value of 0.''16 for the residual absolute astrometric error in CSC positions. This error will be added to the published position errors in the CSC from now on, starting with CSC, version 1.1.

Rots, Arnold H. [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 67, Cambridge, MA 02138 (United States); Budavari, Tamas, E-mail: arots@cfa.harvard.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

2011-01-15

439

Novel phase-coding method for absolute phase retrieval.  

PubMed

This Letter presents a novel absolute phase recovery technique with phase coding. Unlike the conventional gray-coding method, the codeword is embedded into the phase and then used to determine the fringe order for absolute phase retrieval. This technique is robust because it uses phase instead of intensity to determine codewords, and it could achieve a faster measurement speed, since three additional images can represent more than 8(2(3)) unique codewords for phase unwrapping. Experimental results will be presented to verify the performance of the proposed technique. PMID:22660123

Wang, Yajun; Zhang, Song

2012-06-01

440

Sensitive absolute-gravity gradiometry using atom interferometry  

Microsoft Academic Search

We report the demonstration of a sensitive absolute-gravity gradiometer based on light-pulse atom-interference techniques. The gradiometer consists of two absolute accelerometers operated in a differential mode. We report a differential acceleration sensitivity of 4×10-9g\\/Hz1\\/2 and an inferred differential acceleration accuracy of less than 10-9g. This corresponds to a gravity-gradient sensitivity of 4E\\/Hz1\\/2 (1E=10-9 s-2) and an accuracy of better than

J. M. McGuirk; G. T. Foster; J. B. Fixler; M. J. Snadden; M. A. Kasevich

2002-01-01

441

In-flight absolute radiometric calibration of the thematic mapper  

NASA Technical Reports Server (NTRS)

The TM multispectral scanner system was calibrated in an absolute manner before launch. To determine the temporal changes of the absolute radiometric calibration of the entire system, spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM collections over White Sands, New Mexico. By entering the measured values in an atmospheric radiative transfer program, the radiance levels of the in four of the spectral bands of the TM were determined. Tables show values for the reflectance of snow at White Sands measured by a modular 8 channel radiometer, and values for exoatmospheric irradiance within the TM passbands, calculated for the Earth-Sun distance using a solar radiometer.

Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

1983-01-01

442

Homodyne interferometry with quadrature fringe detection for absolute gravimeter.  

PubMed

An absolute gravimeter is based on interferometric displacement measurement during repeated free falls of a target mirror in a high vacuum. A suitable homodyne quadrature laser interferometer is developed and reported. Standard deviation of the mean absolute gravity value in a typical two-day measurement session is less than 1×10-8??m/s2. Additionally, digital demodulation of the interference signal using a 90° phase-shift filter based on the Hilbert transform is presented. A combination of optical and digital quadrature phase shifts is shown to be helpful to improve accuracy in homodyne interferometers with the accelerated target mirror. PMID:24922433

Svitlov, Sergiy; Araya, Akito

2014-06-01

443

Absolute Stability Analysis of a Phase Plane Controlled Spacecraft  

NASA Technical Reports Server (NTRS)

Many aerospace attitude control systems utilize phase plane control schemes that include nonlinear elements such as dead zone and ideal relay. To evaluate phase plane control robustness, stability margin prediction methods must be developed. Absolute stability is extended to predict stability margins and to define an abort condition. A constrained optimization approach is also used to design flex filters for roll control. The design goal is to optimize vehicle tracking performance while maintaining adequate stability margins. Absolute stability is shown to provide satisfactory stability constraints for the optimization.

Jang, Jiann-Woei; Plummer, Michael; Bedrossian, Nazareth; Hall, Charles; Jackson, Mark; Spanos, Pol

2010-01-01

444

The IUE Absolute Flux Scale (Gonzalez-Riestra+, 2001)  

NASA Astrophysics Data System (ADS)

Tables tablea1 to tablea6 show the absolute fluxes of the IUE standard stars used for the derivation of the cameras Inverse Sensitivity Curves for the IUE Final Archive. The relative fluxes of the standard stars have been derived with the WD model, and the zero point of the scale has been set by OAO-2 observations. These fluxes define the absolute flux scale of IUE. Table tableb1 contains the model fluxes of the White Dwarf G191 B2B scaled to the OAO-2 flux scale. (7 data files).

Gonzalez-Riestra, R.; Cassatella, A.; Wamsteker, W.

2001-05-01

445

Kinetics of thermal transformations in nanosized chromium films  

NASA Astrophysics Data System (ADS)

The transformations in nanosized chromium layers at different layer thicknesses ( d = 14-154 nm) and thermal treatment temperatures ( T = 673-873 K) were studied by optical spectroscopy, microscopy, and gravimetry. The kinetic curves of conversion at different chromium film thicknesses and treatment temperatures are well approximated by the linear, inverse logarithmic, cubic, and logarithmic functions. The contact potential difference for Cr and Cr2O3 films and photo-emf for Cr-Cr2O3 systems were measured. An energy band diagram of Cr-Cr2O3 systems was constructed. A model of thermal transformation was constructed for Cr films that included the stages of oxygen adsorption, charge carrier redistribution in the contact field of Cr-Cr2O3, and chromium(III) oxide formation.

Surovoi, E. P.; Zaikonnikova, T. M.

2014-01-01

446

Absolute continuity of stable foliations for systems on Banach spaces  

NASA Astrophysics Data System (ADS)

We prove the absolute continuity of stable foliations for C maps of Banach spaces satisfying a globally defined infinitesimal invariant cones condition. Proofs of regularity for center and stable manifolds needed for the main theorem are included. Our results are applicable to dynamical systems generated by ordinary, partial, or functional differential equations, including non-autonomous differential equations that are periodic in time.

Lian, Zeng; Young, Lai-Sang; Zeng, Chongchun

447

Absolute Power Measurement with Transition Edge Sensors and SQUID amplifier  

Microsoft Academic Search

We have developed a new cryogenic radiometer for determining absolute power. This instrument is composed of a superconducting transition edge sensor as a thermometer, a silicon substrate as a heat absorber, and a SQUID amplifier as a readout. The input power is measured with electrical substitution of a heater on the device. By using very sharp transition of the thermometer,

D Fukuda; N Zen; M Ohkubo; K Amemiya; S Kimura; M Ukibe; H Takahashi; M Nakazawa

2006-01-01

448

Regions of absolute ultimate boundedness for discrete-time systems.  

NASA Technical Reports Server (NTRS)

This paper considers discrete-time systems of the Lur'e-Postnikov class where the linear part is not asymptotically stable and the nonlinear characteristic satisfies only partially the usual sector condition. Estimates of the resulting finite regions of absolute ultimate boundedness are calculated by means of a quadratic Liapunov function.

Siljak, D. D.; Weissenberger, S.

1972-01-01

449

Optical testing by absolute length measurement with wavelength tuning interferometer  

NASA Astrophysics Data System (ADS)

The surface shape and the absolute optical thickness of a fused-silica glass parallel plate were measured by wavelength tuning interferometry. An excess fractions method combined with the Fourier based frequency analysis removed a systematic error. The interference orders of the optical thickness fringes were finally estimated, which resulted in an accuracy of a few nanometers for the optical thickness measurement.

Hibino, Kenichi; Kim, Yangjin; Ito, Makoto

2013-05-01

450

Newton's absolute time and space in general relativity  

Microsoft Academic Search

I describe a reference system in a spherically symmetric gravitational field that is built around times recorded by radially moving geodesic clocks. The geodesic time coordinate t and the curvature spatial radial coordinate R result in spacetime descriptions of the motion of the geodesic clocks that are exactly identical with equations following from Newton's absolute time and space used with

Ronald Gautreau

2000-01-01

451

Ultraprecise Absolute Time Synchronization for Distributed Acquisition Systems  

Microsoft Academic Search

In this paper, we describe an algorithm built on top of a precision time protocol (PTP) implementation that allows for synchronization, syntonization and absolute time referencing to coordinated universal time (UTC), including the estimation of timestamp uncertainty. We call this the software grandmaster (SWGM) algorithm, since it provides similar services to a PTP grandmaster clock. We show that SWGM allows

Brian R. Calder; Andrew McLeod

2007-01-01

452

Robust synchronization of absolute and difference clocks over networks  

Microsoft Academic Search

We present a detailed re-examination of the problem of inexpensive yet accurate clock synchronization for networked devices. Based on an empirically validated, parsimonious abstraction of the CPU oscillator as a timing source, accessible via the TSC register in popular PC architectures, we build on the key observation that the measurement of time differences, and absolute time, requires separate clocks, both

Darryl Veitch; Julien Ridoux; Satish Babu Korada

2009-01-01

453

Robust synchronization of absolute and difference clocks over networks  

Microsoft Academic Search

We present a detailed re-examination of the problem of inexpensive yet accurate clock synchronization for networked devices. Based on an empirically validated, parsimonious ab- straction of the CPU oscillator as a timing source, accessible via the TSC register in popular PC architectures, we build on the key observation that the measurement of time differences, and absolute time, requires separate clocks,

Darryl Veitch; Julien Ridoux; Satish Babu Korada

2009-01-01

454

Is There a Rule of Absolute Neutralization in Nupe?  

ERIC Educational Resources Information Center

A previously prosed rule of absolute neutralization (merging underlying low vowels) is eliminated in an alternative analysis including instead a rule that "breaks" the feature matrix of certain low vowels and redistributes the features of each vowel as a sequence of vowel-like transition plus (a). (Author/RM)

Krohn, Robert

1975-01-01

455

Relative versus Absolute Stimulus Control in the Temporal Bisection Task  

ERIC Educational Resources Information Center

When subjects learn to associate two sample durations with two comparison keys, do they learn to associate the keys with the short and long samples (relational hypothesis), or with the specific sample durations (absolute hypothesis)? We exposed 16 pigeons to an ABA design in which phases A and B corresponded to tasks using samples of 1 s and 4 s,…

de Carvalho, Marilia Pinhiero; Machado, Armando

2012-01-01

456

The absolute stereochemistry of a diterpene from Ballota aucheri.  

PubMed

The semi-synthetic transformation of hispanolone, isolated from Ballota africana, into 6beta-hydroxy-15,16-epoxylabda-8,13(16),14-trien-7-one has established an ent-labdane absolute stereochemistry for a diterpene metabolite originally isolated from B. aucheri. PMID:12770589

Gray, Christopher A; Rivett, Douglas E A; Davies-Coleman, Michael T

2003-06-01

457

Results from a U.S. Absolute Gravity Survey.  

National Technical Information Service (NTIS)

Using the recently completed JILA absolute gravity meter, we made a survey of twelve sites in the United States. Over a period of eight weeks, the instrument was driven a total distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyo...

M. A. Zumberge J. E. Faller J. Gschwind

1982-01-01

458

Hyperstereopsis in helmet-mounted NVDs: absolute distance perception  

Microsoft Academic Search

Modern helmet-mounted night vision devices, such as the Thales TopOwl helmet, project imagery from intensifiers mounted on the side of the helmet onto the helmet faceplate. The increased separation of the cameras induces hyperstereopsis - the exaggeration of the stereoscopic disparities that support the perception of relative depth around the point of fixation. Increased camera separation may also affect absolute

Patrick Flanagan; Geoffrey W. Stuart; Peter Gibbs

2007-01-01

459

Determination of Absolute Intensities of gamma Transitions in Neutron Resonances.  

National Technical Information Service (NTIS)

A method for determination of absolute intensities of gamma-transitions in neutron resonances is developed. It is based on comparing two time-of-flight spectra measured simultaneously: spectrum of capture in the isotope under study and spectrum of neutron...

F. Bechvarzh M. E. Montero-Kabrera S. Pospishil S. A. Telezhnikov

1985-01-01

460

Ophthalmoplegic migraine. Two patients with an absolute response to indomethacin.  

PubMed

Two patients suffering from ophthalmoplegic migraine had a strictly unilateral headache absolutely responsive to indomethacin, but not to other non-steroidal anti-inflammatory drugs, analgesics or corticosteroids. Such observations raise a therapeutic alternative and suggest that ophthalmoplegic migraine may present with different headache phenotypes. PMID:19732068

Pareja, J A; Churruca, J; de la Casa Fages, B; de Silanes, C López; Sánchez, C; Barriga, F J

2010-06-01

461

Series that Converge Absolutely but Don't Converge  

ERIC Educational Resources Information Center

If a series of real numbers converges absolutely, then it converges. The usual proof requires completeness in the form of the Cauchy criterion. Failing completeness, the result is false. We provide examples of rational series that illustrate this point. The Cantor set appears in connection with one of the examples.

Kantrowitz, Robert; Schramm, Michael

2012-01-01

462

Some Simple Physical Models for Absolute Plate Motions  

Microsoft Academic Search

Although the relative angular velocities of the earth's plates are well known, the velocities relative to the underlying mantle and the nature of the driving forces are not. We calculate several solutions to the 'absolute' velocity field from the hypothesis that no net torque is exerted on the lithosphere as a whole and a series of assumptions about the forces

Sean C. Solomon; Norman H. Sleep

1974-01-01

463

Asymmetric synthesis of fortucine and reassignment of its absolute configuration.  

PubMed

A convergent and enantioselective synthesis of fortucine was achieved from the starting materials tyrosine methyl ester and 3-hydroxy-4-methoxybenzaldehyde. The synthesis is based on two key steps mediated by a hypervalent iodine reagent. This work has enabled us to reassign the absolute configuration of the natural product reported in the literature. PMID:24782396

Beaulieu, Marc-André; Ottenwaelder, Xavier; Canesi, Sylvain

2014-06-16

464

Mechanism for an absolute parametric instability of an inhomogeneous plasma  

NASA Astrophysics Data System (ADS)

The structure of plasma oscillations in a region of parametric spatial amplification has been studied experimentally for the first time. A new mechanism for an absolute parametric instability has been observed. This mechanism operates when a pump wave with a spatial structure more complicated than a plane wave propagates through a plasma which is inhomogeneous along more than one dimension.

Arkhipenko, V. I.; Budnikov, V. N.; Gusakov, E. Z.; Romanchuk, I. A.; Simonchik, L. V.

1984-05-01

465

Absolute radiometric calibration of detectors between 200-600 A  

NASA Technical Reports Server (NTRS)

A description is given of the experimental methods used in the calibration procedure, taking into account the source of radiant energy, the monochromator, the absolute standard detector, and the transfer standards. The experimental apparatus is discussed. A graph showing the effect of beam motion on the detected signal is presented and a block diagram of the calibration electronic system is provided.

Saloman, E. B.; Ederer, D. L.

1975-01-01

466

The Absolute Thermoelectric Power of Some Dilute Liquid Sodium Alloys  

Microsoft Academic Search

The absolute thermoelectric powers of liquid sodium and of dilute liquid alloys of sodium with silver, cadmium, indium and tin have been measured within the temperature range 100–460°C. The thermopower of liquid sodium is decreased by the addition of cadmium, indium or tin, with cadmium having the smallest and indium the greatest effect, whereas it is increased slightly on the

H. A. Davies

1969-01-01

467

Least absolute deviations estimation for the censored regression model  

Microsoft Academic Search

This paper proposes an alternative to maximum likelihood estimation of the parameters of the censored regression (or censored 'Tobit') model. The proposed estimator is a generalization of least absolute deviations estimation for the standard linear model, and, unlike estimation methods based on the assumption of normally distributed error terms, the estimator is consistent and asymptoti- cally normal for a wide

James L. Powell

1984-01-01

468

Absolute calibration in the 1750 - 3350 A region  

NASA Technical Reports Server (NTRS)

The absolute flux measurements in the rocket ultraviolet made by Bohlin, Frimout, and Lillie (BFL) are revised using a more correct treatment of the air extinction that enters the air calibration of their instrument. The absorption by molecular oxygen and ozone, Rayleigh scattering, and extinction by aerosols is tabulated for general use in ultraviolet calibrations performed in air. The revised absolute flux of eta UMa and final fluxes for alpha Lyr and zeta Oph are presented in the 1750-3350 A region. The absolute flux of the star eta UMa is compared to four other independent determinations in the 1200-3400 A region and a maximum difference of 35% is found near 1500 A between the OAO-2 and Apollo 17 fluxes. The rocket measurements of BFL, the ANS and TD-1 satellite data, and the Apollo 17 data are compared to the ultraviolet fluxes from the OAO-2, demonstrating a photometric reproducibility of about + or - 3 percent. Therefore, all four sets of spectrophotometry can be reduced to a common absolute scale.

Strongylis, G. J.; Bohlin, R. C.

1977-01-01

469

Maximization of the region of exponential absolute stability.  

NASA Technical Reports Server (NTRS)

The problem of selecting a regulator vector which yields the largest estimate of the region of exponential absolute stability is considered. Reformulation of an extended version of the Popov frequency condition in terms of a nonnegative polynomial gives the desired algorithm in mathematical programming format.

Karmarkar, J. S.; Siljak, D. D.

1972-01-01

470

Europe's Other Poverty Measures: Absolute Thresholds Underlying Social Assistance  

ERIC Educational Resources Information Center

The first thing many learn about international poverty measurement is that European nations apply a "relative" poverty threshold and that they also do a better job of reducing poverty. Unlike the European model, the "absolute" U.S. poverty threshold does not increase in real value when the nation's standard of living rises, even though it is…

Bavier, Richard

2009-01-01

471

Bahadur representations for the median absolute deviation and its modifications  

Microsoft Academic Search

The median absolute deviation about the median (MAD) is an important univariate spread measure having wide appeal due to its highly robust sample version. A powerful tool in treating the asymptotics of a statistic is a linearization, i.e., a Bahadur representation. Here we establish both strong and weak Bahadur representations for the sample MAD. The strong version is the first

Satyaki Mazumder; Robert Serfling

2009-01-01

472

Population-based absolute risk estimation with survey data  

PubMed Central

Absolute risk is the probability that a cause-specific event occurs in a given time interval in the presence of competing events. We present methods to estimate population-based absolute risk from a complex survey cohort that can accommodate multiple exposure-specific competing risks. The hazard function for each event type consists of an individualized relative risk multiplied by a baseline hazard function, which is modeled nonparametrically or parametrically with a piecewise exponential model. An influence method is used to derive a Taylor-linearized variance estimate for the absolute risk estimates. We introduce novel measures of the cause-specific influences that can guide modeling choices for the competing event components of the model. To illustrate our methodology, we build and validate cause-specific absolute risk models for cardiovascular and cancer deaths using data from the National Health and Nutrition Examination Survey. Our applications demonstrate the usefulness of survey-based risk prediction models for predicting health outcomes and quantifying the potential impact of disease prevention programs at the population level.

Kovalchik, Stephanie A.; Pfeiffer, Ruth M.

2013-01-01

473

The Neurocognitive Components of Pitch Processing: Insights from Absolute Pitch  

Microsoft Academic Search

The natural variability of pitch naming ability in the population (known as absolute pitch or AP) provides an ideal method for in- vestigating individual differences in pitch processing and auditory knowledge formation and representation. We have demonstrated the involvement of different cognitive processes in AP ability that reflects varying skill expertise in the presence of similar early age of onset

Sarah J. Wilson; Dean Lusher; Catherine Y. Wan; Paul Dudgeon; David C. Reutens

2008-01-01

474

Do individuals with Williams syndrome possess absolute pitch?  

Microsoft Academic Search

Although absolute pitch (AP) is a rare skill in typical development, individuals with Williams syndrome (WS) are often referred to as possessing this musical ability. However, there is paucity of research on the topic. In this article, 2 studies were conducted to evaluate AP in WS. In Study 1, seven musically trained individuals with WS, 14 musically trained typically developing

Pastora Martínez-Castilla; María Sotillo; Ruth Campos

2011-01-01