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Abstract

In 2002 the circulation of nutrients and their balance was studied in a large, shallow, eutrophic Lake Gardno. It was determined that throughout a year 1516 Mg of total nitrogen and 155 Mg of total phosphorus reach the lake. Approximately 67% of nitrogen and 87% of phosphorus reaching the lake flows out of it, the rest remains in the lake. About 45% of the total loss of nitrogen results from denitrification, and about 53% from sedimentation. The greatest effect on the circulation of nutrients in Lake Gardno is exerted by the mixing of water caused by strong winds resulting in the upward movement of the surface layers of bottom sediments. This causes increased resuspension and sedimentation, which mask similar processes resulting from the outer load of nutrients and from autochtonie processes and products, which are one or two orders ofa magnitude smaller.
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Authors and Affiliations

Jan Trojanowksi
Czesława Trojanowska
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Abstract

Several conclusions and recommendations concerning sediment trap geometry, the technique of their deployment and interpretation of measurements results are described in this paper. Only cylindrical sediment traps are able to cope with the diverse and dynamic environment of glaciated fjords. The relation between different trap parameters shows the optimal proportion of cylinder diameter as being between 6 and 10 cm and ratio length/diameter not less than 7/1. During the peak of the melting season in Kongsfjorden (Spitsbergen) the rate of sedimentation of total matter reaches over 900 g m–2 d–1 and the velocity of brackish water current can reach 80 cm s–1 on the surface. Owing to the high productivity of Arctic fiords and large concentration of suspended mineral matter it is possible to collect of large samples in a short time, therefore prevention of sediment traps by swimmers is not necessary.

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Authors and Affiliations

Marek Zajączkowski
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Abstract

Chemical and process engineering offers scientific tools for solving problems in the biomedical field, including drug delivery systems. This paper presents examples of analyzing the dynamics of dispersed systems (aerosols) in medical inhalers to establish a better relationship between the test evaluation results of these devices and the actual delivery of drugs to the lungs. This relationship is referred to as in vitro-in vivo correlation (IVIVC). It has been shown that in dry powder inhalers (DPls), the aerosolization process and drug release times are determined by the inhalation profile produced by the patient. It has also been shown that inspiratory flow affects the size distribution of aerosols generated in other inhalation devices (vibrating mesh nebulizers, VMNs), which is due to the evaporation of droplets after the aerosol is mixed witha dditional air taken in by the patient. The effects demonstrated in this work are overlooked in standard inhaler testing methods, leading to inaccurate information about the health benefits of aerosol therapy, thus limiting the development of improved drug delivery systems.
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Authors and Affiliations

Agata Dorosz
1
ORCID: ORCID
Arkadiusz Moskal
1
ORCID: ORCID
Tomasz R. Sosnowski
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Chemical and Process Engineering, Waryńskiego 1, 00-645 Warsaw, Poland

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