Relevant bibliographies by topics / Pulsar: generale

Academic literature on the topic 'Pulsar: generale'

Author: Grafiati
Published: 9 March 2023
Last updated: 10 March 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Pulsar: generale.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Pulsar: generale"

1

Bailes, M. "Geodetic Precession in Binary Pulsars." Symposium - International Astronomical Union 125 (1987): 410. http://dx.doi.org/10.1017/s0074180900161054.

Full text
Abstract:
We have calculated the probability of observing geodetic precession in the binary pulsar PSR1913+16 for several different progenitor systems. Such an observation would support the asymmetric kick hypothesis for the origin of pular velocities. The results are shown to be dependent on the assumed progenitor but not to a strong degree. It is concluded that the probability of an observation to date is less than 20 percent in contrast to past predictions. In 15 years we expect this figure to be near 60 percent. We conclude that the null result to date cannot be taken as evidence against the asymmetric kick hypothesis for the origin of pulsar velocities. We develop our model and apply it to binary pulsars in general. We conclude that the likelihood of observing geodetic precession in the near future is low.A complete version of this paper is soon to be submitted to a scientific journal.
APA, Harvard, Vancouver, ISO, and other styles
2

Yin, Qian, Yefan Li, Jiajie Li, Xin Zheng, and Ping Guo. "Pulsar-candidate Selection Using a Generative Adversarial Network and ResNeXt." Astrophysical Journal Supplement Series 264, no. 1 (December 13, 2022): 2. http://dx.doi.org/10.3847/1538-4365/ac9e54.

Full text
Abstract:
Abstract Pulsar research has been a hot topic in the area of astronomy since they were first discovered. Pulsar discovery is fundamental for pulsar research. While pulsars are now visible across the electromagnetic spectrum, pulsar searches with modern radio telescopes are most promising. As the performance of astronomical instruments improves, the number of pulsar candidates detected by modern radio telescopes grows at an exponential rate. The application of artificial intelligence to the field of pulsar-candidate identification can automatically and efficiently address the identification problem with enormous amounts of data. However, there are still significant challenges in enhancing the accuracy of deep-learning-based pulsar-candidate identification. These problems result primarily from the fact that real pulsar data is scarce: the number of candidates that can be successfully identified as real pulsars (positive samples) is much smaller than those candidates that turn out to not be pulsars but instead radio-frequency interference or noise (negative samples). This makes it difficult to train a machine-learning model that can accurately select those candidates that are real pulsars. Therefore a novel pulsar-candidate identification framework is proposed that combines a deep convolutional generative adversarial neural network (DCGAN) and a deep aggregation residual network (ResNeXt). To overcome sample imbalance, the DCGAN is utilized to generate images that approximate real pulsars, while observed and generated candidates are employed together to train the pulsar-candidate identification model ResNeXt. Experiments on the HTRU Medlat data set back up the framework’s performance. The precision, recall, and F1-score of the framework are 100%.
APA, Harvard, Vancouver, ISO, and other styles
3

MANCHESTER, R. N. "PULSAR SEARCHING AND TIMING." International Journal of Modern Physics D 22, no. 01 (January 2013): 1341007. http://dx.doi.org/10.1142/s0218271813410071.

Full text
Abstract:
More than 2000 pulsars are now known. These pulsars may be divided into a number of different classes according to their period, period derivative, binary properties, emission characteristics and so on. Some important classes have relatively few members, e.g. double-neutron-star binary systems, and so continued searches for currently unknown pulsars are important. Such searches are being undertaken at various observatories around the world. Somewhat unexpectedly, the Fermi Gamma-ray Observatory, has proved to be an efficient pulsar detector, especially for millisecond pulsars (MSPs). The great stability of pulsar periods, especially for MSPs, leads to a number of important applications of pulsar timing. The detection and study of relativistic orbit perturbations in double-neutron-star systems has proved to be a powerful tool with measurements of the original binary pulsar, PSR B1913+16, and more recently the double pulsar, PSR J0737-3039A/B, showing that Einstein's general theory of relativity accurately describes these gravitational interactions. Direct detection of gravitational waves using pulsar timing is close to being achieved with the development of pulsar timing arrays (PTAs) in Europe, North America and Australia. Combining data from these PTAs to form the International Pulsar Timing Array (IPTA) will lead to improved significance of such a detection. Ultimately, detailed study of gravitational-wave sources will be possible using future large radio telescopes such as FAST and the SKA.
APA, Harvard, Vancouver, ISO, and other styles
4

Stairs, I. H. "Binary pulsars and tests of general relativity." Proceedings of the International Astronomical Union 5, S261 (April 2009): 218–27. http://dx.doi.org/10.1017/s1743921309990433.

Full text
Abstract:
AbstractBinary pulsars are a valuable laboratory for gravitational experiments. Double-neutron-star systems such as the double pulsar provide the most stringent tests of strong-field gravity available to date, while pulsars with white-dwarf companions constrain departures from general relativity based on the difference in gravitational binding energies in the two stars. Future observations may open up entirely new tests of the predictions of general relativity.
APA, Harvard, Vancouver, ISO, and other styles
5

Desvignes, Gregory, Michael Kramer, Kejia Lee, Joeri van Leeuwen, Ingrid Stairs, Axel Jessner, Ismaël Cognard, Laura Kasian, Andrew Lyne, and Ben W. Stappers. "Radio emission from a pulsar’s magnetic pole revealed by general relativity." Science 365, no. 6457 (September 5, 2019): 1013–17. http://dx.doi.org/10.1126/science.aav7272.

Full text
Abstract:
Binary pulsars are affected by general relativity (GR), causing the spin axis of each pulsar to precess. We present polarimetric radio observations of the pulsar PSR J1906+0746 that demonstrate the validity of the geometrical model of pulsar polarization. We reconstruct the (sky-projected) polarization emission map over the pulsar’s magnetic pole and predict the disappearance of the detectable emission by 2028. Two tests of GR are performed using this system, including the spin precession for strongly self-gravitating bodies. We constrain the relativistic treatment of the pulsar polarization model and measure the pulsar beaming fraction, with implications for the population of neutron stars and the expected rate of neutron star mergers.
APA, Harvard, Vancouver, ISO, and other styles
6

Wielebinski, Richard. "Pulsar Studies at High Radio Frequencies." International Astronomical Union Colloquium 177 (2000): 205–10. http://dx.doi.org/10.1017/s0252921100059480.

Full text
Abstract:
AbstractPulsars were discovered at 81.5 MHz and a lot of the studies of these exciting objects have been made up to the present time at radio frequencies below 1.6 GHz. The reasons for this concentration on the low radio frequency characteristics of pulsars is the fact that the spectra are very steep and that very few radio telescopes exist that are capable of efficient operations at high radio frequencies. The Effelsberg 100-m radio telescope of the Max-Planck-Institut fur Radioastronomie operates regularly up to the frequency of 50 GHz and was used to study pulsars at cm/mm-wavelengths. In the southern skies the Parkes 64-m telescope has been used to study pulsars up to 8.4 GHz. One pulsar has been detected at 87 GHz with the 30-m Pico Veleta telescope of IRAM.The studies of pulsars over the whole frequency range are of great importance because this is necessary for the elucidation of the mechanism that is responsible for the pulsar emission. The high polarization of pulsar radio emission at lower radio frequencies has supported the hypothesis of a coherent emission mechanism, which is required to generate the high luminosity. It has been known for some time that pulsars, unlike other radio sources, have a lower polarization at high radio frequencies. Recently a change of pulsar spectrum, a flattening or possibly an inversion has been observed at the highest radio frequencies. The inversion of the pulsar spectrum seems to coincide with a complete depolarization of some pulsars.Millisecond pulsars are less luminous than normal pulsars. This makes them even more difficult to detect at higher radio frequencies. Recent observations have extended the spectra of ten millisecond pulsars up to 4.85 GHz. The results imply that millisecond pulsars have properties very similar to normal (slow) pulsars, which suggests similar emission mechanisms.
APA, Harvard, Vancouver, ISO, and other styles
7

Lorimer, Duncan R., and Maura A. McLaughlin. "Probing fundamental physics with pulsars." Proceedings of the International Astronomical Union 5, H15 (November 2009): 131–36. http://dx.doi.org/10.1017/s1743921310008513.

Full text
Abstract:
AbstractPulsars provide a wealth of information about General Relativity, the equation of state of superdense matter, relativistic particle acceleration in high magnetic fields, the Galaxy's interstellar medium and magnetic field, stellar and binary evolution, celestial mechanics, planetary physics and even cosmology. The wide variety of physical applications currently being investigated through studies of radio pulsars rely on: (i) finding interesting objects to study via large-scale and targeted surveys; (ii) high-precision timing measurements which exploit their remarkable clock-like stability. We review current surveys and the principles of pulsar timing and highlight progress made in the rotating radio transients, intermittent pulsars, tests of relativity, understanding pulsar evolution, measuring neutron star masses and the pulsar timing array
APA, Harvard, Vancouver, ISO, and other styles
8

Liu, Xiao-Jin, Benjamin Stappers, and Cees Bassa. "Kinematic effects on high order spin frequency derivatives." Proceedings of the International Astronomical Union 13, S337 (September 2017): 362–63. http://dx.doi.org/10.1017/s1743921317009061.

Full text
Abstract:
AbstractThe radial velocity of a pulsar induces the Doppler effect on its intrinsic spin properties. In particular, it can generate a contribution to the frequency second derivative. We estimated this effect for each of the International Pulsar Timing Array pulsars. We also assessed the possibility of measuring the frequency second derivative in the observational data.
APA, Harvard, Vancouver, ISO, and other styles
9

Izvekova, V. A., A. D. Kuz'min, V. M. Malofeev, W. Sieber, A. Jessner, and R. Wielebinski. "New Observations of the Time Alignment of Pulse Profiles at High and Low Frequencies." International Astronomical Union Colloquium 128 (1992): 7–8. http://dx.doi.org/10.1017/s0002731600154630.

Full text
Abstract:
Exact timing measurements allow a determination of the phase shift between observations of a pulsar at different frequencies. It has become clear from these observations that a simple dipole magnetic field configuration can not explain the time lag observed for many pulsars between profiles at high frequencies (Kuz'min et al. 1986).There are cases which might better be explained by a combination of dipole and quadrupole field components (Davies et al. 1984). We report in this paper on new pulsar time alignment observations of a number of pulsars at high and low frequencies which support the general picture outlined above.
APA, Harvard, Vancouver, ISO, and other styles
10

Ronchi, M., N. Rea, V. Graber, and N. Hurley-Walker. "Long-period Pulsars as Possible Outcomes of Supernova Fallback Accretion." Astrophysical Journal 934, no. 2 (August 1, 2022): 184. http://dx.doi.org/10.3847/1538-4357/ac7cec.

Full text
Abstract:
Abstract For about half a century, the radio pulsar population was observed to spin in the ∼0.002–12 s range, with different pulsar classes having a spin-period evolution that differs substantially depending on their magnetic fields or past accretion history. The recent detection of several slowly rotating pulsars has reopened the long-standing question of the exact physics, and observational biases, driving the upper bound of the period range of the pulsar population. In this work, we perform a parameter study of the spin-period evolution of pulsars interacting with supernova fallback matter and specifically look at the fallback accretion disk scenario. Depending on the initial conditions at formation, this evolution can differ substantially from the typical dipolar spin-down, resulting in pulsars that show spin periods longer than their coeval peers. By using general assumptions for the pulsar spin period and magnetic field at birth, initial fallback accretion rates, and including magnetic field decay, we find that very long spin periods (≳100 s) can be reached in the presence of strong, magnetar-like magnetic fields (≳1014 G) and moderate initial fallback accretion rates (∼1022−1027 g s−1). In addition, we study the cases of two recently discovered periodic radio sources, the pulsar PSR J0901–4046 (P = 75.9 s) and the radio transient GLEAM-X J162759.5–523504.3 (P = 1091 s), in light of our model. We conclude that the supernova fallback scenario could represent a viable channel to produce a population of long-period isolated pulsars that only recent observation campaigns are starting to unveil.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Pulsar: generale"

1

RIGOSELLI, MICHELA. "X-ray emission from the magnetic polar caps of old rotation-powered pulsars." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/277373.

Full text
Abstract:
Le stelle di neutroni sono il risultato dell'evoluzione di stelle massive dopo l'esplosione di supernova. Il progetto di questa Tesi di PhD consiste nello studio dell'emissione di raggi X da parte di stelle di neutroni isolate di età superiore a 100000 anni. Sono stati analizzati dati provenienti dal satellite XMM-Newton (ESA). Per estrarre la miglior informazione possibile dai dati, ho implementato un metodo di maximum likelihood (ML) e l'ho utilizzato per estrarre spettri e profili pulsati di pulsar vecchie in banda X, che poi sono stati analizzati con raffinati di emissione. La Tesi è strutturata come segue: nei primi tre capitoli illustro le proprietà principali delle stelle di neutroni, con particolare attenzione ai processi termici e non termici che producono raggi X. I raggi X non termici sono prodotti da particelle relativistiche accelerate da campi elettromagnetici; una frazione di queste particelle viene accelerata verso la superficie della stella, e riscalda le zone delle calotte polari magnetiche. La componente termica, che può essere prodotta dall'intera superficie o da una parte, viene solitamente descritta come un corpo nero; tuttavia, la presenza di intensi campi magnetici superficiali influenza le proprietà della materia, e la radiazione emessa è ampiamente anisotropa. Nel Capitolo 4 descrivo come ho generato spettri e profili pulsati sintetici, utilizzando modelli di emissione che considerano calotte polari ricoperte di un'atmosfera di idrogeno magnetizzata. Mi sono basata su un software esistente che, dato un certo set di parametri relativi alle proprietà fisiche della stella, stima l'intensità della radiazione prodotta. Successivamente, esso somma i contributi degli elementi di superficie che sono visibili all'osservatore alle differenti fasi di rotazione. Quindi, nel Capitolo 5 descrivo come ho implementato un software di analisi che si basa sul metodo di ML. Dato un certo modello, esso stima i parametri più probabili che ricostruiscono i dati osservati, nella fattispecie il numero di conteggi relativo alla sorgente e al background. Ho validato il metodo e dimostrato che esso è particolarmente efficace per sorgenti deboli, quali sono la maggior parte delle pulsar vecchie. Successivamente, ho applicato i metodi finora descritti ad alcune pulsar vecchie. Nel Capitolo 6 riporto l'analisi di PSR J0726-2612, una pulsar radio che ha alcune delle caratteristiche delle XDINSs: un periodo di rotazione lungo, un intenso campo magnetico, ed emissione X termica. Grazie ad un'analisi congiunta dello spettro e del profilo pulsato, ho mostrato che la presenza di impulsi radio in PSR J0726-2612, così come la loro assenza nelle XDINSs, potrebbe essere dovuta ad un'orientazione differente rispetto all'osservatore. Nel Capitolo 7 presento il caso di PSR B0943+10, una pulsar con emissione X sia termica sia non termica ma che, nonostante sia un rotatore allineato, ha una grande frazione pulsata. Sono riuscita a riappacificare i due diversi aspetti grazie ad un'attenta analisi di ML e all'intrinseca anisotropia dell'emissione termica prodotta da un'atmosfera magnetizzata. Nel Capitolo 8 ho invece applicato il metodo di ML su sette pulsar poco brillanti, delle quali quattro avevano diverse analisi già pubblicate in letteratura, ma con risultati discordanti, mentre le altre tre non erano ancora state rivelate in banda X. Ho trovato tracce evidenti di emissione termica solo in due oggetti, più un accenno nello spettro pulsato di un terzo oggetto. Infine, ho considerato tutte le pulsar vecchie che emettono raggi X termici e ho confrontato le misure di temperatura, raggio e luminosità alle aspettative dei modelli teorici. In particolare, ho scoperto che le aree di emissione sono generalmente in accordo con quelle previste dal modello di dipolo magnetico rotante, purché vengano considerati anche effetti di proiezione geometrica e modelli di emissione realistici, quali appunto i modelli di atmosfera magnetizzata.
Neutron stars are the remnants of massive stars whose cores collapse during the supernova explosions. The project of this PhD Thesis consisted in the study of the X-ray emission from isolated neutron stars older than about 100000 years. The work was based mainly on data obtained with the XMM-Newton satellite (ESA). To extract the best possible information from the data, I implemented a maximum likelihood (ML) technique and used it to derive the X-ray spectra and pulse profiles of several old pulsars, that were then studied with state-of-the-art models of X-ray emission. The Thesis is structured as follows: in the first three chapters I outline the main properties of neutron stars, with a major focus on the thermal and nonthermal processes that produce X-rays. The nonthermal X-rays are produced by relativistic particles accelerated by rotation-induced electric fields and moving along the magnetic field lines. A fraction of these particles is accelerated backward and returns on the stellar surface, heating the magnetic polar caps. The thermal component, that can be produced by the whole stellar surface or by small hot spots, can be described, in a first approximation, by a blackbody. However, the presence of intense surface magnetic fields strongly affects the properties of matter, and the emergent radiation is widely anisotropic. In Chapter 4, I describe how I generated synthetic spectra and pulse profiles using thermal emission models that consider polar caps covered by a magnetized hydrogen atmosphere or with a condensed iron surface. I relied on an existing software that, given a set of stellar parameters, evaluates the emerging intensity of the radiation. A second software, which I adapted on the sources I analyzed in the Thesis, collects the contribution of surface elements which are in view at different rotation phases from a stationary observer. Then, in Chapter 5, I describe how I implemented an analysis software that relies on the ML method. It estimates the most probable number of source and background counts by comparing the spatial distribution of the observed counts with the expected distribution for a point source plus an uniform background. I demonstrated that the ML method is particularly effective for dim sources, as most old pulsars are. Subsequently, I applied the methods described above to some old pulsars. In Chapter 6, I report the analysis of PSR J0726-2612, a radio pulsars that shares some properties with the radio-silent XDINSs, as the long period, the high magnetic field, and the thermal X-ray emission from the cooling surface. Thanks to an in-depth analysis of the combined spectrum and pulse profile, I showed that the presence of radio pulses from PSR J0726-2612, as well as the absence from the XDINSs, might simply be due to different viewing geometries. In Chapter 7, I present the case of PSR B0943+10, a pulsar with a nonthermal and thermal X-ray spectrum but that, despite being an aligned rotator, has a large pulsed fraction. I could reconcile the two opposite properties analyzing with the ML the spectrum and the pulse profile, and considering the magnetic beaming of a magnetized atmosphere model, that well fits the thermal component. In Chapter 8, I applied the ML method to seven old and dim pulsars, of which four had controversial published results, and three were so far undetected. I found convincing evidence of thermal emission only in the phase-averaged spectrum of two of them, plus a hint for a thermal pulsed spectrum in a third object. Finally, I considered all the old thermal emitters and I compared their observed temperatures, radii and luminosities to the expectations of the current theoretical models for these objects. In particular, I found that the emitting area are generally in agreement with the polar cap regions evaluated in a dipole approximation, if the combined effects of geometry projections plus realistic thermal models (as the magnetic atmosphere) are taken into account.
APA, Harvard, Vancouver, ISO, and other styles
2

Venter, Christo. "Millisecond pulsars and pulsar wind nebulae as sources of gamma rays and cosmic rays / C. Venter." Thesis, North-West University, 2008. http://hdl.handle.net/10394/2067.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Venter, Christo. "The effect of general relativistic frame dragging on millisecond pulsar visibility for the H.E.S.S. telescope / C. Venter." Thesis, North-West University, 2004. http://hdl.handle.net/10394/215.

Full text
Abstract:
It has been noted by several authors that General Relativistic frame dragging in rotating neutron stars is a first order effect which has to be included in a self-consistent model of pulsar magnetospheric structure and associated radiation and transport processes. To this end, I undertook the present study with the aim of investigating the effect of General Relativity (GR) on millisecond pulsar (MSP) visibility. I developed a numerical code for simulating a pulsar magnetosphere, incorporating the GR-corrected expressions for the electric potential and field. I included curvature radiation (CR) due to primary electrons accelerated above the stellar surface, as well as inverse Compton scattering (ICS) of thermal X-ray photons by these electrons. I then applied the model to PSR J0437-4715, a prime candidate for testing the GR-Electrodynamic theory, and examined its visibility for the H.E.S.S. telescope. I also considered the question of whether magnetic photon absorption would take place for this particular pulsar. In addition, I developed a classical model for comparison with the GR results. I found that the typical electron energies and associated CR photon energies are functions of position above the polar cap (PC). These energies are also quite smaller in the GR case than in the classical case due to the different functional forms of the GR and classical electric fields. I found the CR energy cut-off to be ~ 4 GeV compared to the well-known classical value of ~ 100 GeV. Since the H.E.S.S. energy threshold is ~ 100 GeV, it seems as though the CR component will not be visible, contrary to wide-held opinion. However, the ICS component seems to be well in excess of the H.E.S.S. energy threshold and is expected to be visible. I also found that no pair production will take place for PSR J0437-4715. Hopefully, forthcoming H.E.S.S. observations will provide validation of these results. KEY WORDS: General relativistic frame dragging, GR electrodynamics, millisecond pulsar visibility, non-thermal radiation processes, pair production, H.E.S.S., individual pulsars: PSR J0437-4715.
Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2004.
APA, Harvard, Vancouver, ISO, and other styles
4

Gralla, Samuel E., Alexandru Lupsasca, and Alexander Philippov. "PULSAR MAGNETOSPHERES: BEYOND THE FLAT SPACETIME DIPOLE." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622675.

Full text
Abstract:
Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields will have a significant nondipolar component. We introduce a general analytical method for studying the axisymmetric force-free magnetosphere of a slowly rotating star of arbitrary magnetic field, mass, radius, and moment of inertia, including all the effects of general relativity. We confirm that spacelike current is generically present in the polar caps (suggesting a pair production region), irrespective of the stellar magnetic field. We show that general relativity introduces a similar to 60% correction to the formula for the dipolar component of the surface magnetic field inferred from spindown. Finally, we show that the location and shape of the polar caps can be modified dramatically by even modestly strong higher moments. This can affect emission processes occurring near the star and may help explain the modified beam characteristics of millisecond pulsars.
APA, Harvard, Vancouver, ISO, and other styles
5

Van, Straten Willem Herman Bernadus, and straten@astron nl. "High-Precision timing and polarimeter of PSR JO437-4715." Swinburne University of Technology. School of Biophysical Sciences and electrical Engineering, 2003. http://adt.lib.swin.edu.au./public/adt-VSWT20040311.123754.

Full text
Abstract:
This thesis reports on the recent results of a continuing, high-precision pulsar timing project, currently focused on the nearby, binary millisecond pulsar, PSR J0437_4715. Pulse arrival time analysis has yielded a remarkable series of constraints on the physical parameters of this system and evidence for the distortion of space-time as predicted by the General Theory of Relativity. Owing to the proximity of the PSR J0437_4715 system, relative changes in the positions of the Earth and pulsar result in both annual and secular evolution of the line of sight to the pulsar. Although the changes are miniscule, the effects on the projected orbital parameters are detectable in our data at a high level of significance, necessitating the implementation of an improved timing model. In addition to producing estimates of astrometric parameters with unparalleled precision, the study has also yielded the first three-dimensional orbital geometry of a binary pulsar. This achievement includes the first classical determination of the orbital inclination, thereby providing the unique opportunity to verify the shape of the Shapiro delay and independently confirm a general relativistic prediction. With a current post-fit arrival time residual RMS of 130 ns over four years, the unrivaled quality of the timing data presented herein may eventually contribute to the most stringent limit on the energy density of the proposed stochastic gravitational wave background. Continuing the quest for even greater timing precision, a detailed study of the polarimetry of PSR J0437_4715 was undertaken. This effort culminated in the development of a new, phase-coherent technique for calibrating the instrumental response of the observing system. Observations were conducted at the Parkes 64-m radio telescope in New South Wales, Australia, using baseband recorder technologies developed at York University, Toronto, and at the California Institute of Technology. Data were processed off-line at Swinburne University using a beowulf-style cluster of high-performance workstations and custom software developed by the candidate as part of this thesis.
APA, Harvard, Vancouver, ISO, and other styles
6

Gralla, Samuel E., Alexandru Lupsasca, and Alexander Philippov. "Inclined Pulsar Magnetospheres in General Relativity: Polar Caps for the Dipole, Quadrudipole, and Beyond." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626414.

Full text
Abstract:
In the canonical model of a pulsar, rotational energy is transmitted through the surrounding plasma via two electrical circuits, each connecting to the star over a small region known as a "polar cap." For a dipole-magnetized star, the polar caps coincide with the magnetic poles (hence the name), but in general, they can occur at any place and take any shape. In light of their crucial importance to most models of pulsar emission (from radio to X-ray to wind), we develop a general technique for determining polar cap properties. We consider a perfectly conducting star surrounded by a force-free magnetosphere and include the effects of general relativity. Using a combined numerical-analytical technique that leverages the rotation rate as a small parameter, we derive a general analytic formula for the polar cap shape and charge-current distribution as a function of the stellar mass, radius, rotation rate, moment of inertia, and magnetic field. We present results for dipole and quadrudipole fields (superposed dipole and quadrupole) inclined relative to the axis of rotation. The inclined dipole polar cap results are the first to include general relativity, and they confirm its essential role in the pulsar problem. The quadrudipole pulsar illustrates the phenomenon of thin annular polar caps. More generally, our method lays a foundation for detailed modeling of pulsar emission with realistic magnetic fields.
APA, Harvard, Vancouver, ISO, and other styles
7

CUOFANO, Carmine. "Magnetic fields generated by r-modes in accreting millisecond pulsars." Doctoral thesis, Università degli studi di Ferrara, 2010. http://hdl.handle.net/11392/2389313.

Full text
Abstract:
In rotating neutron stars the existence of the Coriolis force allows the presence of the so-called Rossby oscillations (r-modes) which are known to be unstable to emission of gravitational waves. In the Thesis, for the first time, we introduce the magnetic damping rate in the evolution equations of r-modes. We show that r-modes can generate very strong toroidal fields in the core of accreting millisecond pulsars by inducing differential rotation. We shortly discuss the instabilities of the generated magnetic field and its long time-scale evolution in order to clarify how the generated magnetic field can stabilize the star. Finally we discuss the possible astrophysical scenarios.
APA, Harvard, Vancouver, ISO, and other styles
8

Icdem, Burcin. "Viscous Time Scale In Accreting Powered Pulsars And Anomalous X-ray Pulsars." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613373/index.pdf.

Full text
Abstract:
In this thesis we analyse X-ray data of accretion powered low mass and high mass X-ray binaries to understand the nature of their accretion mechanisms by searching for some clues of viscous time-scales of their accretion discs, if they have, in their low frequency power density spectra created from their long-term X-ray observations, or by doing pulse timing analysis with much shorter X-ray data to detect the effects of torque fluctuations caused by the accreting material on the pulsar. The low mass and high mass X-ray binaries we analysed have breaks in their power density spectra, which are attributed to the role of viscosity in the formation of accretion discs. Although, the time-scales corresponding to these break frequencies are smaller than the predictions of the Standard theory of accretion discs, the sources give consistent results among themselves by displaying the expected correlation between their break and orbital frequencies. The correlation curve of LMXBs implies thicker appearing accretion discs than those assumed by the theory. The dichotomy of the HMXBs on this curve points out the different origins of accretion that these sources may have, and offers a way to distinguish the stellar-wind fed systems from the Roche-lobe overflow systems. The timing and spectral analysis of Swift J1626.6-5156 reveal a correlation between the spin-up rate and the luminosity of the source implying that the pulsar is accretion-powered. This correlation together with the characteristics of the X-ray spectra enables us to estimate the magnetic field and the distance of the source. The AXP 1E 2259+586 does not display any signs of viscous time-scale in its low frequency power density spectra, and its pulse timing analysis gives a much smaller torque noise value than that expected from accretion powered pulsars. In addition, the analysis results presented in this thesis reveal magnetar-like glitches which differ than those of radio pulsars, due to the presence of the strong magnetic field of the pulsar. These results eliminate the possibility that the AXP is an accretion-powered pulsar.
APA, Harvard, Vancouver, ISO, and other styles
9

Yuen, Rai. "Pulsar Magnetosphere Revisited: Emission Geometry and the Synthesis of the Vacuum-Dipole and the Rotating-Magnetosphere Models." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10011.

Full text
Abstract:
We reconsider the vacuum-dipole model (VDM) and the corotating-magnetosphere model (CMM) for pulsar electrodynamics. Both the VDM and the CMM are fatally flawed as stand-alone models. The former model is used for deriving certain pulsar parameters, such as the surface magnetic field strength and characteristic age, but it lacks the plasma required to emit the observed radiation. The latter model introduces important concepts, such as the Goldreich-Julian charge density and corotation electric field, which form the basis for more detailed models, but it neglects the inductive electric field. When this field is included, the model is unstable to growth of large-amplitude electric oscillations when subject to a temporal perturbation. Furthermore, the predicted highly-relativistic magnetospheric plasma given by the two models is inconsistent with results obtained from observations with the Double Pulsar system. We therefore propose a way of synthesizing the VDM and the CMM for obliquely rotating pulsars. We first modify the VDM to a "minimal" model by assuming that the parallel component of the inductive electric field is screened by charges. We define a class of synthesized models as a linear combination of a fraction y times the minimal model and 1 - y times the CMM. We suggest that the synthesized model provides a basis for understanding the abrupt changes in the magnetospheres of some pulsars, which can alter their slowing down rates. The synthesized model also implies that the velocity of the magnetospheric plasma depends on y and the position of the emission point, which is determined numerically based on the obliquity and viewing angles for emission heights close to stellar surface in dipolar magnetic field structure. We also explore the field structure by including higher order terms in the ratio of the radius to the light-cylinder radius in the magnetic field and explore the implications of these additional terms.
APA, Harvard, Vancouver, ISO, and other styles
10

Bernard, Franck. "Anesthesie generale pour cesarienne : comparaison, par oxymetrie pulsee, de deux methodes de preoxygenation." Rennes 1, 1992. http://www.theses.fr/1992REN1M051.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Pulsar: generale"

1

Lyne, A. G. Pulsar astronomy. 2nd ed. Cambridge: Cambridge University Press, 1998.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

1923-, Graham-Smith Francis Sir, ed. Pulsar astronomy. 3rd ed. Cambridge: Cambridge University Press, 2006.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Lyne, A. G. Pulsar astronomy. Cambridge [England]: Cambridge University Press, 1989.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Venancio Pulgar: Autonomía e identidad del Zulia. Zulia: Universidad del Zulia, Ediciones del Vice Rectorado Académico, 2008.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Marquand, John P. H.M. Pulham, Esquire. Chicago: Academy Chicago Publishers, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Francisco Martínez de la Rosa. Hernán Pérez del Pulgar, el de las hazañas. Granada [Spain]: Caja General de Ahorros de Granada, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Śekhāvata, Sumana. Pulisa praśāsana: Rājasthāna Pulisa Mahānideśaka Kāryālaya ke sandarbha meṃ. Jodhapura: Mahārājā Mānasiṃha Pustaka Prakāśa Śodha Kendra, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Śekhāvata, Sumana. Pulisa praśāsana: Rājasthāna Pulisa Mahānideśaka Kāryālaya ke sandarbha meṃ. Jodhapura: Mahārājā Mānasiṃha Pustaka Prakāśa Śodha Kendra, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Śekhāvata, Sumana. Pulisa praśāsana: Rājasthāna Pulisa Mahānideśaka Kāryālaya ke sandarbha meṃ. Jodhapura: Mahārājā Mānasiṃha Pustaka Prakāśa Śodha Kendra, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Śekhāvata, Sumana. Pulisa praśāsana: Rājasthāna Pulisa Mahānideśaka Kāryālaya ke sandarbha meṃ. Jodhapura: Mahārājā Mānasiṃha Pustaka Prakāśa Śodha Kendra, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Pulsar: generale"

1

Burgay, Marta, Delphine Perrodin, and Andrea Possenti. "General Relativity Measurements from Pulsars." In Timing Neutron Stars: Pulsations, Oscillations and Explosions, 53–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2020. http://dx.doi.org/10.1007/978-3-662-62110-3_2.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Sanayei, Ali, and Otto E. Rössler. "Taffy-Puller, Topology and General Relativity." In Emergence, Complexity and Computation, 209–13. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06781-0_20.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Abbott, M. A. "Monitoring Oxygen Saturation Levels in the Early Recovery Phase of General Anaesthesia." In Pulse Oximetry, 165–71. London: Springer London, 1986. http://dx.doi.org/10.1007/978-1-4471-1423-9_21.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Thornton, J. A. "Use of Oximetry in Dental Out-patients Undergoing Controlled Sedation and General Anaesthesia." In Pulse Oximetry, 135–37. London: Springer London, 1986. http://dx.doi.org/10.1007/978-1-4471-1423-9_17.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Ogawa, Rei. "Long-Pulsed 1064 nm Nd:YAG Laser Treatment for Keloids and Hypertrophic Scars." In Textbook on Scar Management, 271–78. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44766-3_32.

Full text
Abstract:
AbstractThere are many therapeutic options for keloids and hypertrophic scars, including surgery, radiation, corticosteroids, 5-fluorouracil, cryotherapy, laser therapy, anti-allergy agents, anti-inflammatory agents, bleaching creams, and make-up therapies. In terms of laser therapy, we have used long-pulsed 1064 nm Nd:YAG laser to treat keloids and hypertrophic scars. This laser was developed for the treatment of vascular diseases, including inflammatory scars that exhibit neovascularization. The depth that is reached is determined by the spot size, the laser power, and the fluence: the larger the spot size, power, or fluence, the deeper the laser beam penetrates. The laser should generally be applied to the skin surface with the following standard treatment settings: a spot diameter of 5 mm, an energy density of 75 J/cm2, an exposure time per pulse of 25 ms, and a repetition rate of 2 Hz.
APA, Harvard, Vancouver, ISO, and other styles
6

Seeman, J., D. Schulte, J. P. Delahaye, M. Ross, S. Stapnes, A. Grudiev, A. Yamamoto, et al. "Design and Principles of Linear Accelerators and Colliders." In Particle Physics Reference Library, 295–336. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-34245-6_7.

Full text
Abstract:
AbstractLinear accelerators (linacs) use alternating radiofrequency (RF) electromagnetic fields to accelerate charged particles in a straight line. Linacs were invented about 95 years ago and have seen many significant technical innovations since. A wide range of particle beams have been accelerated with linacs including beams of electrons, positrons, protons, antiprotons, and heavy ions. Linac parameter possibilities include pulsed versus continuous wave, low and high beam powers, low and high repetition rates, low transverse emittance beams, short bunches with small energy spreads, and accelerated multiple bunches in a single pulse. The number of linacs around the world has grown tremendously with thousands of linacs in present use, many for medical therapy, in industry, and for research and development in a broad spectrum of scientific fields. Researchers have developed accelerators for scientific tools in their own right, being awarded several Nobel prizes. Moreover, linacs and particle accelerators in general have enabled many discovery level science experiments in related fields, resulting in many Nobel prizes as well.
APA, Harvard, Vancouver, ISO, and other styles
7

Kirov, K. "Pulsed Surface Wave Sustained Discharges: Modelling." In Advanced Technologies Based on Wave and Beam Generated Plasmas, 509–10. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-017-0633-9_40.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Díaz, Rodolfo E. "On the Sharpest Possible Pulse that a Finite Radiator Can Generate." In Ultra-Wideband, Short-Pulse Electromagnetics, 381–88. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2870-8_44.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Venter, C., and O. C. De Jager. "Spectral Constraints for Millisecond Pulsars Due to General Relativistic Frame Dragging." In Multiwavelength Approach to Unidentified Gamma-Ray Sources, 399–407. Dordrecht: Springer Netherlands, 2005. http://dx.doi.org/10.1007/1-4020-3881-x_42.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Lamiri, Mohamed, Mohammed El Ghzaoui, and Bilal Aghoutane. "Monopole Patch Antenna to Generate and Detect THz Pulses." In Advances in Terahertz Technology and Its Applications, 273–91. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5731-3_16.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Pulsar: generale"

1

Sozzi, Michele, Katia Tragni, Stefano Selleri, Annamaria Cucinotta, Adrian H. A. Lutey, Pier Gabriele Molari, and Simone Carmignato. "Picosecond and Nanosecond Pulsed Laser Ablation of Aluminium Foil." In ASME 2013 International Manufacturing Science and Engineering Conference collocated with the 41st North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/msec2013-1189.

Full text
Abstract:
The pulsed laser ablation of 20 micron thick aluminium foil is investigated by exposing moving samples to picosecond pulses of wavelength 1064nm and nanosecond pulses of wavelength 515nm and 1030nm. Ablation thresholds and depths are determined for a range of conditions using an optical microscope and 3D optical profiler. Complete three-dimensional crater profiles for single and multiple pulses are presented. The results reveal a variation in ablation threshold with wavelength, pulse duration and the number of pulses; a large reduction is observed for picosecond pulses. Ablation rates per pulse are expressed by general equations and found to vary strongly with both laser type and the number of pulses. The green nanosecond laser is found to ablate most efficiently for fluences above 10J/cm2, whilst the picosecond source is instead advantageous for low fluences. A large reduction in ablation depth per pulse is observed with an increasing number of pulses. The present work affords prediction of scribe and cut parameters for the processing of thin aluminium layers and, more generally, characterises the driving parameters of pulsed picosecond and nanosecond laser ablation of metals.
APA, Harvard, Vancouver, ISO, and other styles
2

Lei, Zhu. "Generation of femtosecond pulse trains from a short cavity dye laser pumped by cw and pulsed laser." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.wr3.

Full text
Abstract:
A short cavity dye laser (SCDL) as an efficient way to generate ultrashort pulses was first used by Roess.1 Recently, SCDL mixed with the saturable absorber DODCI pumped by pulsed laser had been studied theoretically and experimently.2,3 Here, it was found that under strong interactions within three bodies of laser field, DODCI and dye molecules, femtosecond pulse trains could be generated in the proper conditions.
APA, Harvard, Vancouver, ISO, and other styles
3

Maiorano, M., F. De Paolis, A. A. Nucita, and A. Franco. "Advantages of including globular cluster millisecond pulsars in Pulsar Timing Arrays." In Proceedings of the MG16 Meeting on General Relativity. WORLD SCIENTIFIC, 2023. http://dx.doi.org/10.1142/9789811269776_0314.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Borgström, S., E. Fill, J. Larsson, T. Starczewski, S. Svanberg, and C. G. Wahlström. "X-Ray Spectroscopic Investigation of Optical-Field Ionized Plasmas." In High Resolution Fourier Transform Spectroscopy. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/hrfts.1994.wc3.

Full text
Abstract:
Soft X-ray spectra of N, O, C, S, He and Ar ions generated by optical-field ionization with fs pulses are reported. The experiments were carried out by focusing pulses of the high-power Ti:Sapphire laser of the Lund Institute of Technology (wavelength 800 nm, pulse duration 150 fs, pulse energy 150 mJ) to a 60 µm diameter spot below a pulsed gas nozzle or within a windowless pulsed gas cell, using N2, O2, CO2, SF6, He and Ar as parent gases.
APA, Harvard, Vancouver, ISO, and other styles
5

Haner, M., F. Spano, and Warren S. Warren. "Experimental techniques for generation of arbitrarily shaped and phased nanosecond and picosecond pulse trains." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.fh5.

Full text
Abstract:
We have shown, in a series of recent papers, that generation of laser pulse sequences with completely controlled delays, pulse shapes, and relative phases permits selective vibrational inversion, enhances velocity resolution in gases, and differentiates between relaxation mechanisms in condensed phases. We present new results with two fundamentally different technologies developed in our laboratory to produce such pulse sequences. Nanosecond pulse shaping and phase shifting is accomplished by acoustooptic modulation of a continuous ring laser.1 We have now experimentally demonstrated pulse envelopes as complicated as Such a complicated shape cannot be generated by other methods in the literature but is needed to compensate for inhomogeneous effects in electronic transitions. We routinely generate phase shifted pulse sequences using these and simpler shapes. Picosecond pulse shaping is accomplished by transient injection locking, and currently generates 150-ps, 10-μJ pulses. We can also generate subnanosecond phase shifts.2 Our fastest pulse shaper and electrooptic modulator, in conjunction with this injection locked system, generate a digital approximation to any shape we wish with <100-ps resolution.2 These results are in agreement with our theoretical models of transient injection locking. Technological limitations of these approaches and comparison with other methods are discussed.
APA, Harvard, Vancouver, ISO, and other styles
6

Bennett, G. T., E. Fry, and F. Sogandares. "Temporal response of laser-induced photoacoustic pulses in H2O, measured as a function of incident beam energy." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.tud5.

Full text
Abstract:
The second harmonic, 530 nm, of a pulsed YAG laser was used to generate photoacoustic pulses in water and water doped with potassium permanganate. The photodeflection technique1 was used to measure the pressure pulse shape as a function of time. Studies were made for a range of incident pulse energies from several microjoules to the onset of dielectric breakdown in water. The discussion compares the observed time responses to the theory of photoacoustic pulses by Lai and Young.2
APA, Harvard, Vancouver, ISO, and other styles
7

Harvey, J. D., and R. Leonhardt. "A Subpicosecond Argon Pumped Fiber Raman Laser." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/up.1990.wc22.

Full text
Abstract:
Recently it has been demonstrated that a modelocked argon laser operated in the superfluorescent regime, can generate pulses with peak power in the kilowatt region (1, 2). These pulses can be exploited to generate a variety of nonlinear effects. In particular, coupling the pulses into a single mode fibre generates strong stimulated Raman emission in the region of 529nm. This Raman emission precludes the compression of the incident pump pulses by conventional grating pulse compression techniques, but can be used to advantage to generate subpicosecond pulses in a fiber Raman laser. Figure 1. Schematic diagram of the fibre Raman ring laser.
APA, Harvard, Vancouver, ISO, and other styles
8

Lee, Chang-Hee, Kun-Ho Cho, Sang-Yung Shin, and Soo-Young Lee. "New method of optical short-pulse generation using diode lasers." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.wo11.

Full text
Abstract:
Various methods of optical short-pulse generation using diode lasers have been reported. Recently, optical short pulses were generated by applying the electrooptic feedback to self-pulsed solitary1 or external cavity diode lasers.2 We propose a new method of optical short-pulse generation based on negative electrooptic feedback.
APA, Harvard, Vancouver, ISO, and other styles
9

Kashyap, R., M. de Lathouwer, Ph Emplit, M. Haelterman, R. J. Campbell, and D. J. Armes. "Optical dark soliton generation using a fibre Bragg grating." In Photosensitivity and Quadratic Nonlinearity in Glass Waveguides. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/pqn.1995.sab.5.

Full text
Abstract:
There is currently worldwide interest in the theory and transmission of dark solitons for application in communications. Theoretical techniques have been proposed[1-3] for the generation of CW dark soliton pulse trains. One of them has been recently demonstrated recently [4]. The techniques rely on spectral filtering of a train of mode-locked pulses using both conventional phase and amplitude masks[l,5], or on the adiabatic transformation of a beat frequency from two lasers[3,4], A third approach[2] is based on the direct modulation of a CW signal from a DFB laser. In another technique, a chirped fibre grating was used to provide the correct sign of dispersion in a Pr:ZBLAN fibre laser to generate dark pulses[6]. In the spectral filtration technique, the frequency content of mode-locked pulses is first spatially dispersed and this allows for the alteration of the amplitude and phases of the spectral components in the Fourier plane[1]. The Fourier transform of the filtered spectrum generates the dark pulse train. These techniques are generally more suitable for the generation of ultra high repetition rate dark pulse train since it is easier to filter larger bandwidths.
APA, Harvard, Vancouver, ISO, and other styles
10

Taft, G., M. M. Murnane, H. C. Kapteyn, D. R. Yankelevich, A. Knoesen, and R. J. Twieg. "Ultrashort Pulse Second-Order Frequency Resolved Optical Gating with Thin Poled Nonlinear Polymers." In Nonlinear Optics: Materials, Fundamentals and Applications. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/nlo.1996.nthd.3.

Full text
Abstract:
Frequency Resolved Optical Gating (FROG) [1] is a newly-developed technique for determining both the amplitude and phase of an ultrashort pulse.[2] Although there are several variations of the FROG technique which use different nonlinear processes, second harmonic generation (SHG) FROG is particularly well suited for measuring un-amplified nJ pulses directly from a modelocked Ti:sapphire oscillator, since SHG produces a much larger signal than the higher order nonlinear processes. In order for SHG FROG to accurately characterize ultrashort pulses, care must be taken to insure the second harmonic signal is not distorted by the nonlinear material, in phase-matched frequency doubling crystals for example, the group velocity mismatch (GVM) can cause severe distortion of the generated pulses over long interaction lengths. Since this finite phase matching bandwidth becomes less of a problem as the crystal thickness is reduced, the thinnest possible crystals (≈ 50 μm) are generally used for ultrashort-pulse measurement applications.[3] However, even using such short crystals, the crystal has to be optimally oriented to achieve proper phasematching for a given center frequency. Furthermore, fabricating such phasematched, polished, ultra-thin crystals is extremely difficult. Thus, an ideal SHG material for short pulse diagnostics is one that can generate an adequate signal intensity while being thin enough to avoid pulse broadening and precise angle tuning.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Pulsar: generale"

1

Ajuha, S. A Full Mesh ATCA-based General Purpose Data Processing Board (Pulsar II). Office of Scientific and Technical Information (OSTI), June 2017. http://dx.doi.org/10.2172/1431570.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Thomas, Richard L. General Atomics Pulsed Power Capacitor Comparison Test Report. Fort Belvoir, VA: Defense Technical Information Center, June 2015. http://dx.doi.org/10.21236/ada625771.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Fiedler, Curtis J. The Interferometric Detection of Ultrafast Pulses of Laser Generated Ultrasound. Fort Belvoir, VA: Defense Technical Information Center, April 1996. http://dx.doi.org/10.21236/ada312079.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Chin, A. H., R. W. Schoenlein, and T. E. Glover. Ultrashort hard x-ray pulses generated by 90 degrees Thomson scattering. Office of Scientific and Technical Information (OSTI), April 1997. http://dx.doi.org/10.2172/603713.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Kyrala, G. A., R. D. Fulton, J. A. Cobble, G. T. Schappert, and A. J. Taylor. Diagnostics of high-brightness short-pulse lasers and the plasmas they generate. Office of Scientific and Technical Information (OSTI), February 1994. http://dx.doi.org/10.2172/10120583.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Glidden, Steven C., Howard D. Sanders, John B. Greenly, and Daniel L. Dongwoo. Pulsed, Inductively Generated, Streaming Plasma Ion Source for Heavy Ion Fusion Linacs. Office of Scientific and Technical Information (OSTI), April 2006. http://dx.doi.org/10.2172/900203.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Selvaraju, Ragul, Hari Shankar, and Hariharan Sankarasubramanian. Metamodel Generation for Frontal Crash Scenario of a Passenger Car. SAE International, September 2020. http://dx.doi.org/10.4271/2020-28-0504.

Full text
Abstract:
A frontal impact scenario was simulated using a Finite Element Model of a Hybrid III 50th percentile male (LSTC, Livermore CA) along with seatbelt, steering system and driver airbags. The boundary conditions included acceleration pulse to the seat and the outputs including injury measures in terms of Head Injury Criterion (HIC), Normalized Neck Injury Criterion (NIJ) and Chest Severity Index (CSI) were extracted from the simulations. The kinematics of the Hybrid III were validated against the kinematics of post mortem human surrogates (PMHS) available in the literature. Using the validated setup, metamodels were generated by creating a design of varying different parameters and recording the responses for each design. First, the X and Z translation of dummy along the seat is provided as input for which there was no variation in the head injury criterion (HIC). Next, the input pulse to the seat is parameterized along with the seatbelt loading and the results are obtained respectively. The outputs, in terms of injury measures, are generated in the form of metamodels as a function of the parameters. The occupant model used for the frontal crash scenario in LS-Dyna is validated against the previously available crash experimental data. A total of 100 design points was generated with a varying combination of parameters. An increase in various injury measures was observed with an increase in the scale factor of the acceleration pulse. Also, it was found that chest severity index increased with an increase in the scale factor of the seat belt loading force.
APA, Harvard, Vancouver, ISO, and other styles
8

Selvaraju, Ragul, Hari Shankar, and Hariharan Sankarasubramanian. Metamodel Generation for Frontal Crash Scenario of a Passenger Car. SAE International, September 2020. http://dx.doi.org/10.4271/2020-28-0504.

Full text
Abstract:
A frontal impact scenario was simulated using a Finite Element Model of a Hybrid III 50th percentile male (LSTC, Livermore CA) along with seatbelt, steering system and driver airbags. The boundary conditions included acceleration pulse to the seat and the outputs including injury measures in terms of Head Injury Criterion (HIC), Normalized Neck Injury Criterion (NIJ) and Chest Severity Index (CSI) were extracted from the simulations. The kinematics of the Hybrid III were validated against the kinematics of post mortem human surrogates (PMHS) available in the literature. Using the validated setup, metamodels were generated by creating a design of varying different parameters and recording the responses for each design. First, the X and Z translation of dummy along the seat is provided as input for which there was no variation in the head injury criterion (HIC). Next, the input pulse to the seat is parameterized along with the seatbelt loading and the results are obtained respectively. The outputs, in terms of injury measures, are generated in the form of metamodels as a function of the parameters. The occupant model used for the frontal crash scenario in LS-Dyna is validated against the previously available crash experimental data. A total of 100 design points was generated with a varying combination of parameters. An increase in various injury measures was observed with an increase in the scale factor of the acceleration pulse. Also, it was found that chest severity index increased with an increase in the scale factor of the seat belt loading force.
APA, Harvard, Vancouver, ISO, and other styles
9

Claus, Ana, Borzooye Jafarizadeh, Azmal Huda Chowdhury, Neziah Pala, and Chunlei Wang. Testbed for Pressure Sensors. Florida International University, October 2021. http://dx.doi.org/10.25148/mmeurs.009771.

Full text
Abstract:
Currently, several studies and experiments are being done to create a new generation of ultra-low-power wearable sensors. For instance, our group is currently working towards the development of a high-performance flexible pressure sensor. However, with the creation of new sensors, a need for a standard test method is necessary. Therefore, we opted to create a standardized testbed to evaluate the pressure applied to sensors. A pulse wave is generated when the heart pumps blood causing a change in the volume of the blood vessel. In order to eliminate the need of human subjects when testing pressure sensors, we utilized polymeric material, which mimics human flesh. The goal is to simulate human pulse by pumping air into a polymeric pocket which s deformed. The project is realized by stepper motor and controlled with an Arduino board. Furthermore, this device has the ability to simulate pulse wave form with different frequencies. This in turn allows us to simulate conditions such as bradycardia, tachycardia, systolic pressure, and diastolic pressure.
APA, Harvard, Vancouver, ISO, and other styles
10

Bruck, H. A., J. S. Epstein, K. E. Jr Perry, and M. G. Abdallah. Dynamic characterization of short duration stress pulses generated by a magnetic flyer plate in carbon-fiber/epoxy laminates. Office of Scientific and Technical Information (OSTI), November 1995. http://dx.doi.org/10.2172/125087.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Pulsar: generale' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography