Wyniki wyszukiwania - Biblioteka Nauki

1

Assessment of river health in Australia by diatom assemblages - a review

100%

John J.

|

tom Vol. 33, No. 2

95--104

EN

This paper summarises the findings of two national projects carried out by the author, covering the largest area ever investigated on the use of diatoms for monitoring river health in Australia, as well as to recommend future directions in diatom river monitoring in Australia. The first project (1995 to 1998) involved South-west Western Australia – well known for its forests and abundance of streams and rivers. Data on environmental variables and diatom taxa were obtained from 136 sites, out of which 117 were used as reference sites and 29 as monitoring (impacted) sites. Some 20 sites were randomly selected from the reference sites and used as "test sites" to verify internal consistency of the reference sites which were considered to be relatively pristine. The streams and rivers were finally classified into four distinct groups based upon environmental factors and diatom distribution pattern. The second project involved monitoring the health of urban streams around the city of Perth, western Australia. The investigation (1996 to 1999) focussed on classification of the urban streams based on water quality parameters and "stream conditions" and development of a predictive model using diatoms as biomonitors. Close to 180 sites were sampled with 30 environmental variables measured. All the sites were classified on the basis of seven environmental variables with the highest correlation coefficient with the sites, using the multivariate pattern analysis program PATN. The reference and monitoring sites were mostly separated on the basis of environmental factors and distinct diatom assemblages. Currently, a national protocol for assessing the health of all rivers using diatoms in Australia is being compiled.

2

Assessment of river health in Australia by diatom assemblages - a review

100%

John J.

|

tom 33

|

nr 2

3

Lead chalcogenide on silicon infrared sensor arrays

63%

Zogg H. , John J.

|

tom Vol. 6, No. 1

37-46

EN

Narrow gap PB₁₋xSnxSe and PbTe layers are grown epitaxially on Si(111) - substrates by molecular beam epitaxy (MBE). They exhibit high qulity despite the large lattice and thermal expansion mismatch. Thermal strains relax without adversely affecting the structural quality of the layers even at cryogenic temperatures and after many temperature cyclings. This is due to easy glide of misfit dislocations in the layers. Photovoltaic infrared sensor arrays of the Schottky type with Pb blocking contacts are fabricated. Cut-off wavelengths range from 4 to 12 µm. Above 150 K, the noise currents tend to the values predicted by the Schottky theory.At lower temperatures, the noise currents are determined by the density of dislocations in the layers. E. g. for PbSe (7 um cut-off wavelength at 80 K) each threading dislocation in the active area gives rese to a shunt resistance of 1.2. G Ω. If the dislocation density is reduced to below 2 x 10⁶ cm⁻², the influence of the dislocations becomes negligible. Layers such low dislocation densities have been obtained by thermal cycling. Thermal imaging is demonstrated with linear arrays with 128 sensors either hybridly bonded to Si-read-out electronics, or with arrays fabricated in layers grown epitaxially onto Si-chips which already contain the read-out circuits.

4

Nowelizacja przepisów normalizacyjnych dotyczących badań taboru kolejowego w zakresie EMC

51%

Dłużniewski A. , John J. , Laskowski M.

|

tom R. 22, nr 12

402--405, CD

PL

W artykule przedstawiono metodykę pomiarową emisji zaburzeń promieniowanych i przewodzonych w pokładowej sieci zasilającej niskiego napięcia taboru kolejowego na przykładzie obecnie obowiązujących wymagań normatywnych norm serii PN-EN 50121-x-x. Przedstawiono szczegółowo metodykę pomiarową, dopuszczalne po-ziomy emisji zaburzeń promieniowanych na postoju i w trakcie jazdy pojazdu oraz emisji zaburzeń przewodzonych w pokładowej sieci zasilającej niskiego napięcia. Na koniec dokonano porównania obowiązujących wymagań normatywnych w tym zakresie z nowymi edycjami norm kolejowych, które mają zostać wprowadzone niebawem, ze względu na dość stare wydania obecnych dokumentów normalizacyjnych, w oparciu które należy badać tabor kolejowym pod kątem EMC celem spełnienia wymagań normatywnych.

EN

The paper presents the methodology of measurement radiation and conducting disturbance emission in onboard rolling stock power low voltage network in reference to current obligatory normative standard requirements PN-EN 50121-x-x. The article presents in detail the methodology of measurement, methodology of permissible levels of radiation emission disturbance during stand and during vehicle ride and the levels of conducted disturbance emission in on-board low voltage power network. In conclusion paper presents com-parison of obligatory, normative standard requirements in this range and along with new edition of rail standards, which will be deploy soon, due to the old editions of current standards documents based on rolling stock should be tested in terms of EMC in order to fulfill normative requirements.