Wyniki wyszukiwania - Biblioteka Nauki

1

Ocena parametrów 3D wyznaczonych metodą próbkowania spiralnego

100%

Majchrowski R.

|

2012

|

tom R. 16, nr 6

56-59

PL

W Zakładzie Metrologii i Systemów Pomiarowych Politechniki Poznańskiej opracowano nową metodę pomiaru trójwymiarowej geometrii powierzchni bazującą na próbkowaniu spiralnym. Jest to nowe podejście do zagadnienia zbierania punktów z powierzchni za pomocą niekartezjańskiej siatki próbkowania. Pomiar wykonuje się na siatce utworzonej ze zbioru punktów tworzących spiralę Archimedesa. Główną zaletą tej metody jest mniejsza czasochłonność pomiaru w porównaniu z innymi siatkami próbkowania. Stosując siatkę prostokątną, po każdym przejściu końcówki pomiarowej należy wycofać ją w położenie początkowe. Należy także poprzecznie przesunąć stolik pomiarowy o wartość odpowiadającą odległości między kolejnymi przejściami. Jeśli przy próbkowaniu spiralnym może być mowa o odcinkach wejściowym i wyjściowym, to tylko przy rozpoczęciu i przy zakończeniu pomiaru, ponieważ końcówka przez cały czas pomiaru jest w ruchu. Jest to oczywisty zysk czasu, który może wynosić od 30 % do 70 % w porównaniu z czasem przy użyciu siatki prostokątnej. Próbkowanie spiralne rozwiązuje problem czasochłonności pomiarów przestrzennych powierzchni. Jednakże, jak pokazały badania, istnieją różnice w wartościach parametrów 3D, uzyskanych metodą próbkowania spiralnego i metodą siatki prostokątnej. Nie była również znana zależność opisująca wpływ parametrów siatki spiralnej (skok spirali) na wartości parametrów przestrzennych. W artykule przedstawiono analizę wpływu próbkowania spiralnego na parametry topografii powierzchni. Podczas badań korzystano z programów MATLAB, AWK, Statistica. Do pomiarów powierzchni wykorzystano profilometry Perthen, TOPO, Wyko. Za pomocą wymienionych narzędzi opracowano program do analizy i symulacji metody próbkowania spiralnego. Przeprowadzono badania symulacyjne strategii próbkowania spiralnego dla wytypowanych powierzchni.

EN

In the world around us, all the surfaces are rough. Most of surfaces in mechanics are very complicated, and in order to describe it with certain values, the measurement and analysis of some parameters should be performed. Before 1980th, roughness analysis consisted of 2D measurement, which gave twodimensional characteristics of the surface. During the last decades, many scientists and constructors became convinced that the third dimension should be added to the analysis. At present, 3D analysis of the surface geometry is widely accepted, though some disorder in terminology and in 3D parameters classification is still present. One of important problems is also the way of measurement (points collection) for further analysis. Most of known measuring systems collect a number of parallel profiles. Are known also efforts to collect radial profiles from one point. Anyway, the stereometrical surface measurement requires far more time than typical 2D measurement. In the Division of Metrology of Poznan University of Technology the new method of measurement has been worked out, based on spiral sampling. One of the most important merits of this kind of measurement is much shorter time, when the surface of same dimensions is to be measured. When the parallel profiles are being collected, after each movement forward, the useless move back would come, and also the movement in perpendicular direction (step between profiles) would take additional time. Moreover, in each profile, beside the evaluation length, there are allowances for run-up and for overtravel. In spiral sampling, those allowances appear only once, at the beginning and at the end of measuring process, and the stylus collects the point during all the time of movement. Comparing to parallel profiles, the spiral sampling takes 30 % to 70 % less time of measurement.

2

Sztuczna inteligencja w metrologii - systemy ekspertowe do doboru narzędzi pomiarowychgiczny w systemie zarządzania jakością

100%

Majchrowski R.

Pomiary Automatyka Kontrola

|

2004

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tom R. 50, nr 2

44-48

PL

Od samego powstania pierwszych komputerów człowiek powierzał im coraz bardziej skomplikowane i wyszukane problemy, z którymi odpowiednio zaprogramowana maszyna radzi sobie lepiej niż człowiek [5]. Z czasem pojawiły się hipotezy stworzenia sztucznych systemów, które potrafiłyby rozumować i pojmować otaczający nas świat w sposób do tej pory dostępny jedynie "Homo sapiens". Jeden z prekursorów "sztucznej inteligencji" Turing [13] zaproponował nawet test sprawdzający czy stworzoną przez człowieka maszynę można uznać za inteligentną: "Maszyna jest nazwana inteligentną, jeśli zewnętrzny obserwator nie jest w stanie odróżnić jej odpowiedzi od odpowiedzi człowieka mogącego zastepować maszynę. Jedną z koncepcji takiego, ale jednocześnie inteligentnego systemu są tzw. "Systemy ekspertowe"".

EN

From the moment when the very first computer was created a man his given it tasks with which a properly programmed machine can cope much better than he himself [5]. These tasks gradually became more and more complicated. This is how first hypothensis emerged to create artificial systems, capable of analyze and understand the surrounding world in such a way as so far only a "Homo sapiens" could do it. One of the first inventor of so called "artificial intelligence" Turing [13] proposed even a test verifying whether a machine created by a man can be considered as an intelligent one: "Machine is intelligent if an externally observing person is not able to distinguish a difference between its answer and the answer of a man who could replace the machine. One of the concepts of such an intelligent system is "Expert systems"".

3

Modified relationships between the occurrence of photoprotecting carotenoids of phytoplankton and Potentially Destructive Radiation in the sea [commun.]

63%

Majchrowski R. , Ostrowska M.

Oceanologia

|

1999

|

tom No. 41 (4)

589-599

EN

The paper analyses the statistical relationships between photoprotecting pigment concentrations (principally selected groups of carotenoids), chlorophyll a concentrations and absolute values of the natural irradiance in the sea. The data from 404 sites in various regions (the authors' own investigations and data available on the Internet - about 3000 data sets altogether) were examined. This analysis confirms the close relationships between the occurrence of photoprotecting pigments and irradiance at short waves in the PAR range (λ< 480 nm). Modified statistical relationships between the relative concentration of photoprotecting pigments (ratio of photoprotecting pigments to total chlorophyll a concentration) and the Potentially Destructive Radiation (PDR*) have therefore been elaborated. The latter is the quantity of irradiance from the short-wave PAR range absorbed per chlorophyll a mass unit.

4

Mathematical description of vertical algal accessory pigment distributions in oceans - a brief presentation [commun.]

63%

Majchrowski R. , Ostrowska M.

Oceanologia

|

2009

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tom No. 51 (4)

561-580

EN

A straightforward mathematical expression for describing the vertical distributions of algal accessory pigments in oceans is presented. To this end ca 1500 empirical datasets of accessory pigment depth profiles gathered during some 200 research cruises in different oceanic regions were analysed. These data were retrieved from the bio-optical databases of SeaBASS and U.S. JGOFS published on the Internet. The statistical relationships were analysed between the concentrations of accessory pigments and the trophic indices of waters, as measured by the surface concentrations of chlorophyll a and the optical depths in different oceanic regions. A mathematical expression was established and formulas based on it were found, approximating the relations between the vertical distributions of accessory pigments and the chlorophyll a concentration. These formulas can be used to model the species composition of algae in different parts of the ocean and in remote sensing algorithms.

5

Mathematical description of vertical algal accessory pigment distributions in oceans – a brief presentation

63%

Majchrowski R. , Ostrowska M.

Oceanologia

|

2009

|

tom 51

|

nr 4

EN

A straightforward mathematical expression for describing the vertical distributions of algal accessory pigments in oceans is presented. To this end ca 1500 empirical datasets of accessory pigment depth profiles gathered during some 200 research cruises in different oceanic regions were analysed. These data were retrieved from the bio-optical databases of SeaBASS and U.S. JGOFS published on the Internet. The statistical relationships were analysed between the concentrations of accessory pigments and the trophic indices of waters, as measured by the surface concentrations of chlorophyll a and the optical depths in different oceanic regions. A mathematical expression was established and formulas based on it were found, approximating the relations between the vertical distributions of accessory pigments and the chlorophyll a concentration. These formulas can be used to model the species composition of algae in different parts of the ocean and in remote sensing algorithms.

6

Influence of photo- and chromatic acclimation on pigment composition in the sea

63%

Majchrowski R. , Ostrowska M.

Oceanologia

|

2000

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tom 42

|

nr 2

EN

The aim of this work was to find statistical relationships between the concentrations of accessory pigments in natural populations of marine phytoplankton and the absolute levels and spectral distributions of underwater irradiance. To this end, empirical data sets from some 600 stations in different parts of the seas and oceans were analysed. These data were obtained from the authors’ own research and from the Internet’s bio-optical data base. They included the vertical distributions of the concentrations of various pigments (identified chromatographically) and the vertical and spectral distributions of the underwater irradiance measured in situ or determined indirectly from bio-optical models. The analysis covered a total of some 4000 points illustrating the dependence of pigment concentration on underwater irradiance characteristics, corresponding to different depths in the sea. The analysis showed that the factor governing the occurrence of photoprotecting carotenoids (PPC) is short-wave radiation λ < 480 nm. A mathematical relationship was established between the relative PPC concentration (relative with respect to the chlorophyll a concentration) and the magnitude of the absorbed radiative energy per unit mass of chlorophyll a from the spectral interval λ < 480 nm, averaged in the water layers Δz = 60 m (or less near the surface) to account for vertical mixing. This absorbed short-wave radiation (λ < 480 nm) was given the name of Potentially Destructive Radiation (PDR∗(z)). Analysis of the relationships between the concentrations of particular photosynthetic pigments (PSP), i.e. chlorophyll b, chlorophyll c, photosynthetic carotenoids (PSC), and the underwater irradiance characteristics indicated that these concentrations were only slightly dependent on the absolute level of irradiance E0(λ), but that they depended strongly on the relative spectral distribution of this irradiance f(λ) = E0(λ)/PAR0. The relevant approximate statistical relationships between the relative concentrations of particular PSP and the function of spectral fitting Fj , averaged in the layer Δz, were derived. Certain statistical relationships between the pigment composition of the phtyoplankton and the irradiance field characteristics are due to the photo- and chromatic acclimation of natural populations of marine phytoplankton. These relationships can be applied in models of the coefficients of light absorption by phytoplankton.

7

Investigations of concrete surface roughness by means of 3D scanner

51%

Grzelka M. , Majchrowski R. , Sadowski Ł.

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tom Z. 251

97-108

EN

This paper presents investigations of the base concrete surface in concrete floors by means of a 3D scanner. Two base concrete surfaces, differing in their preparation, were investigated.

PL

W niniejszym artykule przedstawiono badania topografii (chropowatości 3D) powierzchni warstwy konstrukcyjnej podłóg betonowych za pomocą metody powierzchniowej. W tym celu wykorzystano optyczny skaner współrzędnościowy oraz opracowane oprogramowanie do analizy wyników pomiarów. Badaniom poddano dwie warstwy konstrukcyjne ze zróżnicowanym sposobem przygotowania warstwy konstrukcyjnej. W algorytmach obliczeniowych wykorzystano obowiązujące zależności dla wyznaczania poszczególnych parametrów 3D opisujących charakter badanych powierzchni.

8

Pomiary cech geometrycznych warstwy wierzchniej za pomocą laserowego czujnika konfokalnego

51%

Wieczorowski M. , Majchrowski R. , Jakubowicz M.

|

2016

|

tom R. 89, nr 11

1650--1651

PL

W artykule przedstawiono problematykę bezstykowych pomiarów cech geometrycznych warstwy wierzchniej. Opisano zasadę działania laserowego czujnika konfokalnego. Zaprezento- wano przykłady komercyjnych zastosowań takich czujników oraz zamieszczono przykłady pomiarów uzyskanych laserowym czujnikiem konfokalnym.

EN

Article presents the problem of non-contact measurements of geometric characteristics of the surface. Principle of operation of a confocal chromiotic measuring system. Presented examples of commercial uses of the above-mentioned sensors, and provides the measurement results obtained confocal laser sensor.

9

Zastosowanie pomiarów geometrycznych i analizy obrazów do odwzorowania modelu geometrycznego aparatury wtryskowej silnika okrętowego

51%

Jermak C. , Majchrowski R. , Monieta J.

Silniki Spalinowe

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2011

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tom R. 50, nr 3

PL

W pracy przestawiono zastosowanie nowoczesnych metod do odtworzenia modelu geometrycznego aparatury wtryskowej współczesnych średnioobrotowych okrętowych silników spalinowych. Dane geometryczne pozyskano na podstawie obiektów nowych i eksploatowanych w naturalnych warunkach. Do modelowania wykorzystano również analizę obrazów dwuwymiarowych. Celem było określenie cech geometrycznych głównych elementów aparatury wtryskowej, a w pracy przedstawiono przykładowo wyniki pomiarów i modelowania rozpylacza wtryskiwacza. W wyniku pomiarów geometrycznych możliwe było pozyskanie zbioru punktów i na ich podstawie opracowanie obszarów cyfrowych obiektów. Stosując program komputerowy do modelowania w przestrzeni trójwymiarowej (w formacie 3D) odwzorowano badane elementy.

EN

The paper presents the application of modern methods to reproduce the geometric model of the injection equipment of medium speed marine diesel engines. Geometric data were obtained on the basis of the new objects operated under natural conditions. Analysis of two-dimensional images was also used for modeling. The aim was to determination the geometrical features of the main elements of the injection equipment, and in this work exemplary presents the results of measurements and modeling of the injector nozzle. As a result of geometrical measurements it was possible to obtain a set of points and on the basis of the development of the areas of digital objects. A computer program for modeling three-dimensional space (3D) mapped the test items.

10

Koncepcja projektu uczelniano-przemysłowego dotyczącego badań chropowatości powierzchni

51%

Wieczorowski M. , Cellary A. , Majchrowski R.

|

2007

|

tom nr 9 supl.

103-106

PL

Zgodnie z obowiązującymi w Polsce normami ISO serii 9000 niezbędne jest zapewnienie odpowiedniej wiarygodności pomiarów i ich odtwarzalności w różnych warunkach, tzn. na przykład u dostawcy i odbiorcy. Z analizy literaturowej i wielu dyskusji z użytkownikami przyrządów do pomiaru chropowatości powierzchni wynika, że istnieją bardzo duże rozbieżności pomiędzy różnymi przyrządami. Z tego względu niezbędne staje się przeprowadzenie badań porównawczych,które pozwoliłyby stwierdzić, jakiego rzędu rozbieżności można się spodziewać i w jaki sposób sprawdzać różne przyrządy, aby uniknąć tego typu problemów. W gronie uczestników projektu znalazły się uczelnie i zakłady przemysłowe głęboko zaangażowane w tą tematykę. Planowane jest wykonanie próbek reprezentujących powierzchnie po wybranych rodzajach obróbki ważnych z punktu widzenia aplikacji i rozesłanie tych próbek kolejno do wszystkich użytkowników w celu dokonania pomiarów chropowatości. W trakcie tych badań dokonane zostaną obliczenia wartości grupy wybranych parametrów, a ich wyniki będą przesłane z powrotem w celu dokonania pełnej analizy porównawczej. Razem z próbkami do uczestników projektu zostanie przesłany zestaw wzorców chropowatości powierzchni do wywzorcowania przyrządów.

EN

According to ISO series 9000 standard it is necessary to assure proper fidelity of measurement and their reproducibility in different conditions, i.e. at supplier's and customer's plant. Basing on references and communications it is clear, that there are huge discrepancies between different devices for surface roughness measurements. For this it is very important to make a comparison study to assess these differences and how to verify and calibrate different measuring devices to avoid these kind of problems. In our project there are universities and factories form all over the country deeply involved in roughness analysis. It is planned to manufacture samples representing surfaces after some types of machining processes important from their application point of view and making a round robin test among all the participants. During this research roughness parameters will be calculated and results will be sent back for comparison analysis. Together with samples a set of standards will be sent to check and adjust devices before measurements.

11

Appointing of surface topography parameters to describe the diffuse reflective properties of selected dielectrics

51%

Majchrowski R. , Rozanski L. , Grochalski K.

Measurement Automation Monitoring

|

2017

|

tom Vol. 63, No. 3

78--81

EN

The investigations have been performed in order to choose the specific roughness parameters, which would inform the customer about the diffuse emissive and reflective characteristics of the adhesive tapes used in the thermographic measurements. To achieve that, a series of the surface topography parameters of various adhesive tapes (i.e. objects with diffusive reflective characteristics) and various glass plates (i.e. objects with directional reflective characteristics) has been examined. For the analysis of surface topography the following parameters were selected: Sdr (the Developed Interfacial Area Ratio) and Sdq (the Root Mean Square Surface Slope). These selected parameters seem to be most suitable to describe the properties of the surface in the discussed aspect.

12

Powierzchnia implantu tytanowego piaskowanego hydroksyapatytem

51%

Koper J. K. , Majchrowski R. , Jakubowicz J.

Engineering of Biomaterials

|

2013

|

tom Vol. 16, no. 119

33--39

PL

Praca podejmuje tematykę modyfikacji powierzchni tytanu, stosowanego jako biomateriał w implantach tkanek twardych. Tytan pomimo doskonałych właściwości użytkowych, w zastosowaniach implantacyjnych wymaga przygotowania powierzchni o określonej morfologii, parametrach oraz biozgodności. Celem niniejszej pracy było porównanie komercyjnie stosowanych powierzchni tytanu, poddanych procesowi piaskowania proszkiem HA/TCP (HA - hyroksyapatyt, TCP - fosforan trójwapniowy), w zastosowaniach implantacyjnych. Proces piaskowania miał na celu zwiększenie chropowatości powierzchni i jednocześnie zmianę jej składu chemicznego tak, aby sprzyjała wzrostowi i proliferacji komórek kostnych oraz była bardziej biozgodna. W badaniach wykorzystano polerowaną powierzchnię Ti 99,6% piaskowaną nieużywanym (świeżym) proszkiem oraz proszkiem używanym (po zakończonym cyklu produkcyjnym, tzn. wypiaskowaniu 300 elementów/implantów dentystycznych). Uzyskane w ten sposób próbki zbadano z wykorzystaniem mikroskopii SEM oraz profilometru optycznego, w celu określenia morfologii i geometrii powierzchni. Wyznaczono 11 parametrów 2D/3D, charakteryzujących powierzchnię i jej przydatność w implantach. Odporność korozyjną zbadano w płynie Ringera. W wyniku przeprowadzonych badań stwierdzono, że na powierzchni piaskowanej nieużywanym proszkiem HA występuje większa liczba trwale umocowanych w niej cząstek HA, w porównaniu do powierzchni piaskowanej proszkiem używanym. Powierzchnia taka charakteryzuje się korzystniejszymi parametrami geometrycznymi przy niewielkim spadku odporności korozyjnej, w porównaniu do niepiaskowanej powierzchni Ti 99,6%. Implant piaskowany nieużywanym proszkiem HA, w którym proszki HA są wbite w powierzchnię, posiada potencjalnie lepszą powierzchnię do zajścia procesów osteointegracji i trwałego połączenia z tkanką kostną.

EN

In this work we describe surface modification process of titanium, which is used in hard tissue implant applications. Titanium, although has excellent and useful properties, in the implant applications requires preparation a respective surface morphology. The aim of this work was to compare Ti 99.6% surfaces, used in implant applications, after HA/TCP (HA - hydroxyapatite, TCP - tricalcium phosphate) powder sandblasting. The aim of sandblasting is to increase the surface roughness, together with changing its chemical composition. So, after the treatment the sandblasted surface should enhance cells growth and proliferation and should be more biocompatible, respective for medical applications. For the sandblasting of the polished Ti surfaces we have used one fresh/new hydroxyapatite powder (first time used) and the second one used before in the implant production (after 300 sandblasting series of dental implants). The morphology and geometrical properties of surfa¬ce were investigated using SEM and optical profiler, respectively. Taking into account surface topography and usefulness in implants, the 11 2D/3D surface geometrical and hybrid parameters were determined. The corrosion potentiodynamic tests were done in Ringer solution. We have found that in the surface, sandblasted with fresh HA particles, were embedded more HA inclusions, and the surface is very rough in comparison to surface sandblasted with old HA particles. The corrosion resistance was slightly worse for sandblasted surfaces in comparison to mechanically polished one. Implants sandblasted with using of fresh HA (with embedded and strongly bonded with titanium HA particles) give potentially better surface for osseointegration process and stable bonding with the bone tissue.

13

Latitudinal pattern of abundance and composition of ciliate communities in the surface waters of the Atlantic Ocean

51%

Rychert K. , Nawacka B. , Majchrowski R. , Zapadka T.

Oceanological and Hydrobiological Studies

|

2014

|

tom Vol. 43, No. 4

4436--441

EN

Abundance, biomass, and taxonomic composition of the ciliate community were studied in the surface waters along a transect between 50°S 61°W and 48°N 5°W (Atlantic Ocean, March-April 2011). The abundance of heterotrophic ciliates was low in the equatorial zone (280–320 cells l−1, 0.11–0.12 μg C l−1), but it increased toward both the northern and southern temperate zones with the maximum abundance observed at 44°S (2667 cells l−1, 0.82 μg C l−1). This pattern resembles the global distribution of oceanic primary production, which is low at lower latitudes and high in temperate zones. In temperate zones ciliate abundance peaks during spring and fall. Thus, because the present study was carried out during spring in the northern hemisphere and austral fall in the southern hemisphere, the ciliate abundance at higher latitudes was additionally elevated. Functionally autotrophic Mesodinium rubrum was only observed in the northern hemisphere and tropical waters. Its maximum abundance was observed at 48°N (1080 cells l−1, 1.14 μg C l−1). The most frequently observed ciliates were oligotrichs and choreotrichs. Other important ciliates were haptorids (including M. rubrum) and hypotrichs.

14

Metody symulacyjne wyznaczenia błędów systemu do pomiaru odchyłki okrągłości metodą odniesieniową

51%

Cellary A. , Jermak C. J. , Majchrowski R.

|

tom R. 56, nr 1

8-9

PL

W artykule przestawiono wyniki badań symulacyjnych nowej koncepcji pomiaru odchyłki okrągłości wewnętrznych powierzchni cylindrycznych bazującą na metodzie odniesieniowej. Badania te miały na celu ustalenie wpływu cząstkowych błędów pomiaru, takich jak błąd pomiaru szczeliny pomiarowej oraz błąd związany ze zmianą położenia poprzecznego głowicy pomiarowej, na końcowy rezultat pomiaru odchyłki okrągłości. W trakcie badań testowano algorytm obliczeniowy pod kątem poprawności wykonywanych procedur obliczenia odchyłki okrągłości.

EN

In the paper the results of simulation-based analysis of a new concept of the roundness measurement of inner cylindrical surfaces are presented. The method is based on the reference measurement. An innovative measuring device is equipped with 3 independent air gauges joined together into a special measuring head. The investigations were aimed at determining the influence of particular measurement errors such as the measuring slot error or the error caused by a non-orthodox position of the measuring head on the final result of the roundness measurement. The Gaussian distribution of the error values was assumed for those factors. In the investigations the calculation algorithm underwent the test to evaluate the calculation accuracy as well as the procedure for out-of-roundness measurements.

15

Distributions of photosynthetic and photoprotecting pigment concentrations in the water column in the Baltic Sea: an improved mathematical description

51%

Ston-Egiert J. , Majchrowski R. , Ostrowska M.

Oceanologia

|

2019

|

tom 61

|

nr 1

16

Variability of the specific fluorescence of chlorophyll in the ocean. Part 1. Theory of classical in situ chlorophyll fluorometry

51%

Ostrowska M. , Majchrowski R. , Matorin D. N. , Wozniak B.

Oceanologia

|

2000

|

tom 42

|

nr 2

EN

The range of variability of the fluorescence properties of marine phytoplankton in different trophic types of seas and at different depths in the sea is analysed theoretically. An attempt is also made to interpret artificially induced in situ fluorescence measured with submersible fluorometers. To do this, earlier optical models of light absorption by phytoplankton (see Woźniak et al. 2000, this volume) and actual empirical data were applied. A straightforward theoretical model of artificially photoinduced phytoplankton fluorescence accounting for the complex influence of different photophysiological characteristics of phytoplankton and the optical characteristics of the instrument has been worked out. A physical method of determining chlorophyll a concentrations in seawater from fluorescence measured in situ with contact fluorometers can be based on this model.

17

Influence of non-photosynthetic pigments on the measured quantum yield of photosynthesis

51%

Ficek D. , Majchrowski R. , Ostrowska M. , Wozniak B.

Oceanologia

|

2000

|

tom 42

|

nr 2

EN

The aim of this work was to assess the effect of non-photosynthetic (photoprotecting) pigments on the measured quantum yield of photosynthesis in the sea. The energy absorbed by these pigments is not utilised during photosynthesis. As a result, the measured yield of this process, i.e. the photosynthetic yield referred to the total energy absorbed by all phytoplankton pigments, is less than the actual quantum yield of photosynthesis, i.e. the yield referred to the energy absorbed by photosynthetic pigments only. The model of the absorption properties of marine phytoplankton derived by the authors (see Woźniak et al. 2000, this volume) was employed to determine the relevant contributions of photosynthetic and non-photosynthetic pigments to the total energy absorbed by phytoplankton in different trophic types of seas and at different depths in the water column. On this basis the non-photosynthetic pigment absorption factor fa, which describes the relation between the true and measured quantum yields of photosynthesis, could be characterised. The analysis shows that fa varies in value from 0.33 to 1, and that it depends on the trophic type of sea and the depth in the water column. The values of this factor are usually highest in eutrophic waters and decrease as waters become progressively more oligotrophic. It is also characteristic of fa that it increases with increasing depth in the sea.

18

Influence of underwater light fields on pigment characteristics in the Baltic Sea – results of statistical analysis

45%

Ston-Egiert J. , Majchrowski R. , Darecki M. , Kosakowska A. , Ostrowska M.

Oceanologia

|

2012

|

tom 54

|

nr 1

19

Influence of underwater light fields on pigment characteristics in the Baltic Sea - results of statistical analysis

45%

Stoń-Egiert J. , Majchrowski R. , Darecki M. , Kosakowska A. , Ostrowska M.

Oceanologia

|

2012

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tom No. 54 (1)

7-27

EN

Changes in phytoplankton pigment concentrations in Case 2 waters (such as those of the Baltic Sea) were analysed in relation to the light intensity and its spectral distribution in the water. The analyses were based on sets of empirical measurements containing two types of data: chlorophyll and carotenoid concentrations obtained by HPLC, and the distribution of underwater light fields measured with a MER 2049 spectrophotometer - collected during 27 research cruises on r/v "Oceania" in 1999-2004. Statistical analysis yielded relationships between the total relative (to chlorophyll a concentrations) concentrations of major groups of phytoplankton pigments and optical depth τ, between the total relative concentrations of major groups of photosynthetic pigments (chlorophylls b (C_chl b tot / Cchl a tot), chlorophylls c (C_chl c tot / C_chl a tot) and photosynthetic carotenoids (CPSC tot / C_chl a tot)) and the spectral fitting function (the "chromatic acclimation factor"), and between the total relative concentrations of photoprotective carotenoids (CPPC tot / C_chl a tot) in Baltic waters and the potentially destructive radiation (PDR), defined as the absolute amount of energy in the blue part of the spectrum (400-480 nm) absorbed by unit mass of chlorophyll a. The best approximations were obtained for the total chlorophyll c content, while the relative estimation errors were the smallest (σ_ = 34.6%) for the approximation to optical depth and spectral fitting function. The largest errors related to the approximation of chlorophyll b concentrations: σ_ = 56.7% with respect to optical depth and 57.3% to the spectral fitting function. A comparative analysis of the relative (to chlorophyll a content) concentrations of the main groups of pigments and the corresponding irradiance characteristics in ocean (Case 1) waters and Baltic waters (Case 2 waters) was also carried out. The distribution of C_chl b tot / C_chl a tot ratios with respect to optical depth reveals a decreasing trend with increasing τ for Baltic data, which is characteristic of photoprotective pigments and the reverse of the trend in oceans. In the case of the C_chl c tot approximations, the logarithmic statistical error is lower for Baltic waters than for Case 1 waters: σ_ = 34.6% for Baltic data and σ_ = 39.4% for ocean data. In relation to photoprotective carotenoids (CPPC), ?_ takes a value of 38.4% for Baltic waters and 36.1% for ocean waters. The relative errors of the approximated concentrations of different pigment groups are larger than those obtained for ocean waters. The only exception is chlorophyll c, for which the logarithmic statistical error is about 8.8% lower (σ_ = 34.6% for Baltic waters and 38.2% for ocean waters). Analysis of the errors resulting from the approximations of the photoprotective carotenoid content, depending on the energy characteristics of the underwater irradiance in the short-range part of PAR, showed that the relative errors are 1.3 times higher for Baltic waters than for ocean waters: σ_ = 38.4% for Baltic waters and 32.0% for ocean waters.

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Quantum yield of photosynthesis in the Baltic: a new mathematical expression for remote sensing applications

45%

Wozniak B. , Ficek D. , Ostrowska M. , Majchrowski R. , Dera J.

Oceanologia

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2007

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tom 49

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nr 4

EN

Statistical relationships between the quantum yield of photosynthesis Φ and selected environmental factors in the Baltic have been established on the basis of a large quantity of empirical data. The model formula is the product of the theoretical maximum quantum yield ΦMAX =0.125 atomC quantum−1 and five dimensionless factors fi taking values from 0 do 1: Φ = ΦMAXfa fΔ fc(Ca(0)) fc(PARinh) fE, t. To a sufficiently good approximation, each of these factors fi appears to be dependent on one or at most two environmental factors, such as temperature, underwater irradiance, surface concentration of chlorophyll a, absorption properties of phytoplankton and optical depth. These dependences have been determined for Baltic Case 2 waters. The quantum yield Φ, calculated from known values of these environmental factors, is then applicable in the model algorithm for the remote sensing of Baltic primary production. The statistical error of the approximate quantum yields Φ is 62%.