Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2015 ( 4 )

2014 ( 1 )

2013 ( 5 )

2012 ( 11 )

Custom range...

Search Results: 1 - 10 of 65 matches for " Waclaw Waniak "
All listed articles are free for downloading (OA Articles)
Page 1 /65
Display every page Item
Fast Rotation and Trailing Fragments of the Active Asteroid P/2012 F5 (Gibbs)
Michal Drahus,Waclaw Waniak,Shriharsh Tendulkar,Jessica Agarwal,David Jewitt,Scott S. Sheppard
Physics , 2015, DOI: 10.1088/2041-8205/802/1/L8
Abstract: While having a comet-like appearance, P/2012 F5 (Gibbs) has an orbit native to the Main Asteroid Belt, and physically is a km-sized asteroid which recently (mid 2011) experienced an impulsive mass ejection event. Here we report new observations of this object obtained with the Keck II telescope on UT 2014 August 26. The data show previously undetected 200-m scale fragments of the main nucleus, and reveal a rapid nucleus spin with a rotation period of 3.24 $\pm$ 0.01 hr. The existence of large fragments and the fast nucleus spin are both consistent with rotational instability and partial disruption of the object. To date, many fast rotators have been identified among the minor bodies, which, however, do not eject detectable fragments at the present-day epoch, and also fragmentation events have been observed, but with no rotation period measured. P/2012 F5 is unique in that for the first time we detected fragments and quantified the rotation rate of one and the same object. The rapid spin rate of P/2012 F5 is very close to the spin rates of two other active asteroids in the Main Belt, 133P/Elst-Pizarro and (62412), confirming the existence of a population of fast rotators among these objects. But while P/2012 F5 shows impulsive ejection of dust and fragments, the mass loss from 133P is prolonged and recurrent. We believe that these two types of activity observed in the rapidly rotating active asteroids have a common origin in the rotational instability of the nucleus.
The Sources of HCN and CH3OH and the Rotational Temperature in Comet 103P/Hartley 2 from Time-Resolved Millimeter Spectroscopy
Michal Drahus,David Jewitt,Aurelie Guilbert-Lepoutre,Waclaw Waniak,Albrecht Sievers
Physics , 2012, DOI: 10.1088/0004-637X/756/1/80
Abstract: One of the least understood properties of comets is the compositional structure of their nuclei, which can either be homogeneous or heterogeneous. The nucleus structure can be conveniently studied at millimeter wavelengths, using velocity-resolved spectral time series of the emission lines, obtained simultaneously for multiple molecules as the body rotates. Using this technique, we investigated the sources of CH3OH and HCN in comet 103P/Hartley 2, the target of NASA's EPOXI mission, which had an exceptionally favorable apparition in late 2010. Our monitoring with the IRAM 30 m telescope shows short-term variability of the spectral lines caused by nucleus rotation. The varying production rates generate changes in brightness by a factor of 4 for HCN and by a factor of 2 for CH3OH, and they are remarkably well correlated in time. With the addition of the velocity information from the line profiles, we identify the main sources of outgassing: two jets, oppositely directed in a radial sense, and icy grains, injected into the coma primarily through one of the jets. The mixing ratio of CH3OH and HCN is dramatically different in the two jets, which evidently shows large-scale chemical heterogeneity of the nucleus. We propose a network of identities linking the two jets with morphological features reported elsewhere, and postulate that the chemical heterogeneity may result from thermal evolution. The model-dependent average production rates are 3.5x10**26 molec/s for CH3OH and 1.25x10**25 molec/s for HCN, and their ratio of 28 is rather high but not abnormal. The rotational temperature from CH3OH varied strongly, presumably due to nucleus rotation, with the average value being 47 K.
A photometric and spectroscopic study of WW And - an Algol-type, long period binary system with an accretion disc
Michal Siwak,Stanislaw Zola,Tomasz Szymanski,Maria Kurpinska-Winiarska,Maciej Winiarski,Dorota Koziel-Wierzbowska,Waclaw Waniak,Michal Drahus
Physics , 2012, DOI: 10.1016/j.newast.2012.02.006
Abstract: We have analyzed the available spectra of WW And and for the first time obtained a reasonably well defined radial velocity curve of the primary star. Combined with the available radial velocity curve of the secondary component, these data led to the first determination of the spectroscopic mass ratio of the system at q-spec = 0.16 +/- 0.03. We also determined the radius of the accretion disc from analysis of the double-peaked H-alpha emission lines. Our new, high-precision, Johnson VRI and the previously available Stromgren vby light curves were modelled with stellar and accretion disc models. A consistent model for WW And - a semidetached system harbouring an accretion disc which is optically thick in its inner region, but optically thin in the outer parts - agrees well with both spectroscopic and photometric data.
Rotation State of Comet 103P/Hartley 2 from Radio Spectroscopy at 1 mm
Michal Drahus,David Jewitt,Aurelie Guilbert-Lepoutre,Waclaw Waniak,James Hoge,Dariusz Lis,Hiroshige Yoshida,Ruisheng Peng,Albrecht Sievers
Physics , 2011, DOI: 10.1088/2041-8205/734/1/L4
Abstract: The nuclei of active comets emit molecules anisotropically from discrete vents. As the nucleus rotates, we expect to observe periodic variability in the molecular emission line profiles, which can be studied through mm/submm spectroscopy. Using this technique we investigated the HCN atmosphere of comet 103P/Hartley 2, the target of NASA's EPOXI mission, which had an exceptionally favorable apparition in late 2010. We detected short-term evolution of the spectral line profile, which was stimulated by the nucleus rotation, and which provides evidence for rapid deceleration and excitation of the rotation state. The measured rate of change in the rotation period is +1.00 \pm 0.15 min per day and the period itself is 18.32 \pm 0.03 hr, both applicable at the epoch of the EPOXI encounter. Surprisingly, the spin-down efficiency is lower by two orders of magnitude than the measurement in comet 9P/Tempel 1 and the best theoretical prediction. This secures rotational stability of the comet's nucleus during the next few returns, although we anticipate a catastrophic disruption from spin-up as its ultimate fate.
Waclaw Branicki
Studia Humanistyczne (Kraków. 2003) , 2010,
Abstract: The primary purpose of this article is to answer the question of whether writing a blog defined as a personal diary can help to better understand himself. Self-awareness is a prerequisite for authentic existence. In the first part analyzed the concept of authenticity. Pointed out the relationship of authenticity to the categories of freedom, truth and responsibility. The second part presents the relationship between authentic existence and the process of self-disclosure, which may take place in the blogosphere. In the third part presents the question whether a writing blog affects the level authenticity of existence. It was recognized that a key element of this phenomenon is the sense of responsibility.
Statistical mechanics of complex networks
B. Waclaw
Physics , 2007,
Abstract: The science of complex networks is a new interdisciplinary branch of science which has arisen recently on the interface of physics, biology, social and computer sciences, and others. Its main goal is to discover general laws governing the creation and growth as well as processes taking place on networks, like e.g. the Internet, transportation or neural networks. It turned out that most real-world networks cannot be simply reduced to a compound of some individual components. Fortunately, the statistical mechanics, being one of pillars of modern physics, provides us with a very powerful set of tools and methods for describing and understanding these systems. In this thesis, we would like to present a consistent approach to complex networks based on statistical mechanics, with the central role played by the concept of statistical ensemble of networks. We show how to construct such a theory and present some practical problems where it can be applied. Among them, we pay attention to the problem of finite-size corrections and the dynamics of a simple model of mass transport on networks.
Extremely Non-symmetric, Non-multiplicative, Non-commutative Operator Spaces
Waclaw Szymanski
Mathematics , 2008,
Abstract: Motivated by importance of operator spaces contained in the set of all scalar multiples of isometries ($MI$-spaces) in a separable Hilbert space for $C^*$-algebras and E-semigroups we exhibit more properties of such spaces. For example, if an $MI$-space contains an isometry with shift part of finite multiplicity, then it is one-dimensional. We propose a simple model of a unilateral shift of arbitrary multiplicity and show that each separable subspace of a Hilbert space is the range of a shift. Also, we show that $MI$-spaces are non-symmetric, very unfriendly to multiplication, and prove a Commutator Identity which elucidates the extreme non-commutativity of these spaces.
Random matrices and localization in the quasispecies theory
Bartlomiej Waclaw
Quantitative Biology , 2011, DOI: 10.5506/APhysPolB.42.1141
Abstract: The quasispecies model of biological evolution for asexual organisms such as bacteria and viruses has attracted considerable attention of biological physicists. Many variants of the model have been proposed and subsequently solved using the methods of statistical physics. In this paper I will put forward important but largely overlooked relations between localization theory, random matrices, and the quasispecies model. These relations will help me to study the dynamics of this model. In particular, I will show that the distribution of times between evolutionary jumps in the genotype space follows a power law, in agreement with recent findings in the shell model - a simplified version of the quasispecies model.
Polymerization of Cyclic Esters Initiated by Carnitine and Tin (II) Octoate
Marcin Sobczak,Waclaw Kolodziejski
Molecules , 2009, DOI: 10.3390/molecules14020621
Abstract: Low-molecular weight poly(ε-caprolactone), polylactides and copolymers of ε-caprolactone and lactides were obtained by the polymerization of cyclic esters in the presence of a carnitine/SnOct2 system. Their structures were proven by means of MALDI-TOF, IR and NMR studies. Effects of temperature, reaction time and carnitine dosage on the polymerization process were examined.
Effect of Culinary Processes on the Content of Nitrates and Nitrites in Potatoe
Waclaw Mozolewski,Stefan Smoczynski
Pakistan Journal of Nutrition , 2004,
Abstract: The effect of potato culinary processing on the changes in the content of nitrates and nitrites was determined. The experimental material were potato tubers of Ibis, Mila and Muza varieties with elevated nitrate (175.4 - 250.7 mg NO3 kg-1) and nitrite (1.7 - 4.3 mg NO2 kg-1) content. The losses of nitrites occurring after the preliminary processing (washing, manual peeling and rinsing) were greater than nitrates and ranged from 25 to 75% and from 18 to 40%, respectively. Differences in the losses of these compounds were variety-dependent. During thermal processing of potato tubers with different methods, the losses of these compounds varied and were significantly greater for nitrites (61-98%) than for nitrates (16-62%). The greatest decrease in the content of nitrates was found for deep fried potatoes and for boiling in water. The losses of nitrates are significantly higher in peeled potato tubers subjected to thermal processing with direct contact of the product with water (p=0.05) than in steam or oil.
Page 1 /65
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.