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1
Content available remote On the GJ 436 Planetary System
Maciejewski G., Niedzielski A., Nowak G., Pallé E., Tingley B., Errmann R., Neuhäuser R.
Acta Astronomica
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2014
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Vol. 64, No. 4
323--335
EN
The GJ 436 system contains a transiting planet GJ 436 b which is a hot analogue of Neptune on an eccentric orbit. Recently, two additional transiting sub-Earth planets have been postulated in the literature. We observed three transits of GJ 436 b over the course of three years using two-meter class telescopes, each with a photometric precision better than one millimagnitude. We studied system dynamics based on the existence of the additional planets. We redetermined system parameters, which were in agreement with those found in the literature. We refined the orbital period of GJ 436 b and found no evidence of transit timing variations. The orbital motion of the GJ 436 c planet candidate was found to be significantly affected by the planet b with variations in transit times at a level of 20 minutes. As the orbital period of the GJ 436 d planet candidate remains unknown, our numerical experiments rule out orbits in low-order resonances with GJ 436 b. The GJ 436 system with the hot Neptune and additional two Earth-like planets, if confirmed, would be an important laboratory for studies of formation and evolution of planetary systems.
2
Content available remote Open Clusters in 2MASS Photometry. II. Mass Function and Mass Segregation
Bukowiecki Ł., Maciejewski G., Konorski P., Niedzielski A.
Acta Astronomica
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2012
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Vol. 62, No. 3
281--296
EN
This is a continuation of our study of open clusters based on the 2-Micron All Sky Survey photometry. Here we present the results of the mass function analysis for 599 known open clusters in the Milky Way. The main goal of this project is a study of the dynamical state of open clusters, the mass segregation effect and an estimate of the total mass and the number of cluster members. We noticed that the cluster size (core and overall radii) decreases along dynamical evolution of clusters. The cluster cores evolve faster than the halo regions and contain proportionally less low-mass stars from the beginning of the cluster dynamical evolution. We also noticed, that the star density decreases for the larger clusters. Finally, we found an empirical relation describing the exponential decrease of the mass function slope with the dynamical evolution of clusters.
3
Content available remote Geotechniczne problemy posadowień na gruntach ekspansywnych w Polsce
Niedzielski A., Kumor M. K.
Inżynieria Morska i Geotechnika
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2009
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nr 3
180-190
PL
Pierwotne rozwiązanie nabrzeża dla terminalu DCT. Kotwy klapowe zastosowane po raz pierwszy w Polsce przy budowie terminalu kontenerowego w Gdańsku jako dobre rozwiązania techniczne i ekonomiczne: możliwość spełnienia wymagań polskich norm, oszczędności czasu oraz materiału przy budowie, obniżenie kosztów inwestycji.
EN
Original construction of DCT terminal quay. Flap anchors applied for the first time in Poland at the construction of container terminal in Gdansk as good technical and economical solution: meeting Polish codes criteria, time and material savings, lowering the investment costs.
4
Wykorzystanie wzorów empirycznych do prognozowania swobodnego pęcznienia i ciśnienia pęcznienia iłów poznańskich
Niedzielski A., Kroll M.
Zeszyty Naukowe. Budownictwo / Politechnika Śląska
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2007
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z. 111
331-338
PL
W pracy dokonano porównania wyników badań wskaźników swobodnego pęcznienia i ciśnienia pęcznienia iłów poznańskich z wynikami obliczeń tych parametrów wybranymi wzorami empirycznymi. Wszystkie badania laboratoryjne przeprowadzono na próbkach o nienaruszonej strukturze i naturalnej wilgotności. Analiza wariancji wykorzystana w rozważaniach porównawczych pozwoliła wyodrębnić wzory empiryczne, które najlepiej prognozuj ą parametry pęcznienia iłów poznańskich.
EN
The paper presents comparison of test results of both free swell index and swelling pressure indices of Posnanian clay versus calculated values of these indices obtained from empirical equations. Ali the laboratory tests were conducted on undisturbed samples of natural moisture content. Analysis of variations enabled selection of equations allowing for the best forecast of swelling parameters of Posnanian clay.
5
Content available remote Wpływ niektórych czynników na ocenę stopnia plastyczności glin morenowych i zastoiskowych
Niedzielski A., Tschuschke W., Wierzbicki J.
Zeszyty Naukowe Politechniki Białostockiej. Budownictwo
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2006
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Z. 28, t. 1
227-237
PL
W artykule przedstawiono wyniki analizy wpływu na granice konsystencji, takich czynników jak: zmiana chemizmu medium, czyli wody gruntowej, zmiana operatora wykonującego oznaczenie granic konsystencji, upływ czasu (tzw. efektu Dawsona) oraz skład granulometryczny gruntu. W generalnej ocenie zmienności granic Atterberga przedstawiono spodziewany wpływ podanych wyżej czynników na wskaźnik plastyczności i ocenę stopnia plastyczności podłoża, zbudowanego z wytypowanych gruntów. Do opracowania wyników i wnioskowania zastosowano metody statystyczne; wielozmienną analizę wariancji oraz analizę kowariancji.
EN
The article presents the results of analysis of the effect on Atterberg limits in selected soils of such factors as changes in the chemism of the medium, i.e. ground water, change of the operator determining Atterberg limits, time (the so-called Dawson effect) and granulometric composition of soil. In the general assessment of Atterberg limit variation the expected effect of the above mentioned factors on the plasticity index and the assessment of plasticity was presented in case of subsoil formed from the selected soils. Statistical methods (multivariate analysis of variance, analysis of covariance) were applied to process the results and draw conclusions.
6
Content available remote Kinematical Structure of Wolf-Rayet Winds. II. Internal Velocity Scatter in WN Stars
Niedzielski A., Nugis T., Skórzyński W.
Acta Astronomica
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2004
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Vol. 54, No. 4
405--427
EN
The shortward edge of the absorption core velocities - vblack as determined from low resolution archived IUE spectra from the INES database are presented for three P Cyg profiles of NV 1240, HeII 1640 and NIV 1720 for 51 Galactic and 64 LMC Wolf-Rayet stars of the WN subtype. These data, together with vblack of CIV 1550 line presented in Niedzielski and Skórzyński (2002) are discussed. Evidences are presented that vblack of CIV 1550 rarely displays the largest wind velocity among the four lines studied in detail and therefore its application as an estimator of the terminal wind velocity in WN stars is questioned. An average vblack of several lines is suggested instead but it is pointed out that vblack of HeII 1640 usually reveals the highest observable wind velocity in Galactic and LMC WN stars. It is shown that the stratification strength decreases from WNL to WNE stars and that for WNL stars there exists a positive relation between vblack and the Ionization Potential. The velocity scatter between vblack obtained from different UV lines is found to correlate well with the X-ray luminosity of single WN stars (correlation coefficient R=0.82 for the data obtained from the high resolution IUE spectra) and therefore two clumpy wind models of single WN stars are presented that allow the velocity scatter to persist up to very large distances from the stellar surface (r≈500-1000R*). These models are used to explain the specific features of single WN stars like broad absorption troughs of strong lines having different vblack, X-ray fluxes, IR/radio continua and stratification relations.
7
Ocena przydatności wzoru Langmuira do prognozy ciśnienia pęcznienia iłów poznańskich i warwowych
Niedzielski A., Gogolik S.
Zeszyty Naukowe. Budownictwo / Politechnika Śląska
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2003
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z. 97
129-136
PL
W artykule przedstawiono wyniki obliczeń ciśnienia pęcznienia iłów poznańskich i warwowych na podstawie powierzchni właściwej tych gruntów, przy różnych gęstościach objętościowych szkieletu gruntowego. Wyniki obliczeń porównano z rezultatami badań laboratoryjnych ciśnienia pęcznienia iłów.
EN
The paper presents the results of calculations of swelling pressure of pliocene and varved clays. The calculations were based on specific surface and different dry densities of these soils. The results of calculations were compared with the results of laboratory investigations on swelling pressure of clays.
8
Naprawa zabytkowego muru oporowego przy nabrzeżu portowym na Warcie w Poznaniu
Buczkowski W., Niedzielski A., Lipiński A., Franczak D.
Gospodarka Wodna
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2003
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Nr 8
338-342
PL
W artykule opisano konstrukcję zabytkowego muru oporowego nabrzeża portowego na Warcie w Poznaniu, przedstawiono jego stan techniczny po okresie stuletniej eksploatacji oraz opisano sposób, w jaki dokonano naprawy i zabezpieczenia muru aby przywrócić mu całkowitą sprawność techniczną oraz pierwotny wygląd.
EN
There have been described in the paper the construction of the monumental retaining wall of the port wharf on the Warta in Poznań, its technical state after a hundred years exploitation and the repair works and protection of the wall which have been done to retestore its primary technical efficiency and original appearance.
9
Content available remote First Results of the Semi-Automatic Variability Search
Niedzielski A., Maciejewski G., Czart K.
Acta Astronomica
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2003
|
Vol. 56, No. 3
281--290
EN
A short description of the Semi-Automatic Variability Search is given. Six new red variable stars discovered recently are presented: GSC 02907-00779, GSC 02904-00834, GSC 02908-00024, GSC 02976-00401, BD+42°1814 and HD 76190.
10
Content available remote Kinematical Structure of Wolf-Rayet Winds. I. Terminal Wind Velocity
Niedzielski A., Skórzyński W.
Acta Astronomica
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2002
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Vol. 52, No. 1
81--104
EN
New terminal wind velocities for 164 Wolf-Rayet stars (from the Galaxy and LMC) based on P Cyg profiles of λ1550 CIV resonance line were derived from the archive high and low resolution IUE spectra available form the INES database. The high resolution data on 59 WR stars (39 from the Galaxy and 20 from LMC) were used to calibrate the empirical relation (λminAbs-λpeakEmis) vs. terminal wind velocity, which was then used for determinations of the terminal wind velocities from the low resolution IUE data. We almost doubled the previous most extended sample of such measurements. Our new measurements, based on high resolution data, are precise within 5-7%. Measurements, based on the low resolution spectra have the formal errors of ≈40-60%. A comparison of the present results with other determinations suggests higher precision of ≈20%. We found that the terminal wind velocities for the Galactic WC and WN stars correlate with the WR spectral subtype. We also found that the LMC WN stars have winds slower than their Galactic counterparts, up to two times in the case of the WNE stars. No influence of binarity on terminal wind velocities was found. Our extended set of measurements allowed us to test application of the radiation driven wind theory to the WR stars. We found that, contrary to OB stars, terminal wind velocities of the WR stars correlate only weakly with stellar temperature. We also note that the terminal to escape velocity ratio for the WR stars is relatively low: 2.55±1.14 for the Galactic WN stars and 1.78±0.70 for the Galactic WCs. This ratio decreases with temperature of WR stars, contrary to what is observed in the case of OB stars. The presented results show complex influence of chemical composition on the WR winds driving mechanism efficiency. Our kinematical data on WR winds suggest evolutionary sequence: WNL→WNE→WCE→WCL.
11
Content available remote The Optical Spectrum of HD 4004 (WN 4b). Evidence of Variability
Niedzielski A.
Acta Astronomica
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1998
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Vol. 48, No. 4
729--746
EN
We describe the optical spectrum of Wolf-Rayet star HD 4004 (WN 4b) in the wavelength range from 3900 to 7000 Å. Present observations reveal the stratification effects in the envelope of this star. Also evidence for variability of HeII line λ 5411 is presented. Since no radial velocity variations are observed in the optical spectrum of this star we conclude that HD 4004 is a single Wolf-Rayet star and the observed emission line profile changes are of intrinsic nature.
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