Settling of solid particles in a stratifed ambient fuid is a process widely encountered in geophysical fows. A set of experiments demonstrating the settling behaviour (the pattern of trajectory, variation of particle orientation, and settling velocity with depth) of thin disks descending through a nonlinear density transition was performed. The results showed complex hydrodynamic interactions between a particle and a liquid causing settling orientation instabilities and unsteady particle descent in low to moderate Reynolds number regime. Five phases of settling were observed: two phases with stable horizontal, one with stable vertical disk position, and two reorientation phases; moreover, two local minima of settling velocity were identifed. It was demonstrated that thresholds for local minima and the frst reorientation depend on the settling dynamics in an upper layer, stratifcation conditions, and disk geometry. The comparison of settling behaviour of thin disks varying in diameter revealed that settling dynamics is sensitive to particle geometry mainly in the upper part of density transition with a non-obvious result that the frst minimum velocity is smaller for a disk with a larger diameter than for a disk with a smaller diameter. The analysis of settling trajectory showed that two reorientations are accompanied with a horizontal drift, which may be important in the context of interactions between particles settling in a group.
Food is a product that breaks down quickly and easily. Therefore, it require storage at a low and controlled temperature. Maintaining a constant temperature inside the refrigeration furniture requires removal of the heat which enters the interior of the furniture and the heat produced by stored products. The paper presents methods of heat transfer implementation, such as: heat conduction (including fluid stratification case), natural and forced convection and radiation. Heat balance have been presented for selected refrigeration furniture including the characteristics of its individual parameters. A method for determining the components of a heat balance is also presented.
PL
Żywność jest produktem, który szybko i łatwo się psuje, dlatego wymaga przechowywania w kontrolowanej temperaturze. Zachowanie niezmiennej temperatury wewnątrz mebla chłodniczego wymaga odprowadzenia ciepła, które dopływa do wnętrza mebla z otoczenia i ciepła wytwarzanego przez przechowywany produkt. Omówiono sposoby realizacji procesu przepływu ciepła takie jak: przewodzenie ciepła (w tym stratyfikacja), konwekcja naturalna i sztuczna oraz promieniowanie. Przedstawiono bilans cieplny dla wybranych mebli chłodniczych wraz z charakterystyką jego poszczególnych parametrów. Zaprezentowano również sposób pozwalający wyznaczyć składowe bilansu ciepła.
Celem artykułu jest wykazanie użyteczności narzędzia, jakim jest analiza skupień, w procesach porządkowania stratyfikacyjnego przedsiębiorstw transportowych. Analiza ta, pozwalając na wykrycie określonych struktur w przestrzeni rynku transportowego, może stać się punktem wyjścia do dalszych badań nad wyjaśnianiem procesów stratyfikacji podmiotów tego rynku.
EN
The research on transport may concern many issues, including the entity structures of the transport market, which is filled with diversified behavior of different entities, both on the supply and on the demand side of the market. On each of the sides one can observe layers of entities characterized by similar behavior – in the stratification systems of the market, individual entities in one layer show a similarity of the behavior, which is different between the layers. The goal of the article is to prove the usefulness of the cluster analysis in the processes of stratification arrangement of the transport enterprises. The analysis, by allowing the detection of particular structures in the transport market may become a starting point to further research on the explanation of stratification processes in that market. A ranking of transport and haulage enterprises, in which they were grouped according to the revenues in the year 2014 was used in the article. The procedure of k-means clustering and a further ANOVA were used to obtain the results which allow to conclude that there are in fact clusters on the market, which are different when it comes to crucial economic data. This leads to a conclusion that the use of presented research methods allows to show the processes on the transport market in a new way, thus proving the practical use of cluster analysis.
The paper presents a comparative and statistical analysis of the changes of water quality indices values with depth on the water intake from Dobczyce reservoir. Moreover, seasonal variability of the tested indices was analysed and water quality with its usable values were assessed. Dobczyce reservoir is a 12 km long and 1.0 km wide submountain dam reservoir. The reservoir area at the maximum impoundment level (maximum water level) is 915 ha, its capacity 112.1 mln m3 and mean depth 10.2 m. It is situated 20 south of Krakow, in the malopolskie voivodship, myślenicki county. Raw water from the reservoir is collected on tower intake which makes possible water intake from three depth levels. Real water extraction on the intake is about 1.0 m3 ∙s-1, guaranteed 2.5 m3 ∙ s-1 and permissible 5.5 m3 ∙ s-1. The investigations conducted in 2008 and 2009 covered selected physicochemical water indices: the temperature, pH, turbidity, electrolytic conductivity, total suspended solids, dissolved oxygen, oxygen saturation, silica, phosphates, total phosphorus, as well as bioindicator – chlorophyll „a”. At weekly intervals, water samples for laboratory analyses were collected from three depth levels of the reservoir directly at the tower water intake for Krakow. Physicochemical and biological analyses, using referential methods were conducted in the Laboratory of the Municipal Waterworks and Sewer Enterprise in Krakow. For each analysed index mean values for 2008 and 2009 and for the 2008–2009 period of analyses were computed, divided into the winter (October-March) and summer (April-September) half year and for the calendar year (January-December). Statistical significance of the differences between the values of individual indices registered on various depth levels on the reservoir were estimated by nonparametric U Manna-Whitney’a significance test, on α = 0.05. For all investigated indices box-whiskers plots were made which suggestively presented the median, extreme values and 10–90% percentiles. The assessment of Dobczyce reservoir water for drinking water supply for people was conducted following the methodology described in the Regulation of the Minister of the Environment [Dz. U. 2002 Nr 204, poz. 1728]. Selected quality parameters of the tested water were also confronted with the requirements stated in the Regulation of the Minister of Health dated 29 March 2007 on drinking water quality for people [Dz. U. 2007 nr 61, poz. 417]. Trophic state of Dobczyce reservoir was assessed on the basis of total phosphorus and chlorophyll „a” concentrations, using the criteria stated by OECD. On the basis of data analysis it was established that mean annual values of water temperature, pH, oxygen saturation and concentrations of dissolved oxygen and chlorophyll „a” were decreasing with depth. On the other hand, in the vertical profile, turbidity, electrolytic conductivity, as well concentrations of total suspended solids, phosphates and total phosphorus were increasing. Higher water temperatures and pH values were noted in the summer half-year, whereas dissolved oxygen, oxygen saturation and phosphates in the winter half-year. On average for the investigated period, water collected in Dobczyce reservoir on the depth of 3.55 and 9.65 m was classified, respectively to A2 and A3 water category, therefore it required appropriate typical or high performance typical treatment. On the other hand, due to low oxygen saturation in the summer half-year, water on the level of 15.87 m did not meet the standards. Irrespective of the depth, pH and salinity fulfilled the requirements for water intended for direct consumption by people, whereas water turbidity was unsatisfactory all the time. Mean annual concentrations of total phosphorus qualify water collected in the reservoir as mezotrophic, while average and maximum concentrations of chlorophyll „a” allow to regard the water as respectively mezotrophic or eutrophic. Due to relatively big differences in values of the analysed indices, better quality raw water intended for running water outside the growing period supply should be skillfully collected from various depths – generally in the from the shallowest level, in the vegetation season from the middle level and from the lowest level on case higher concentrations of chlorophyll „a” and plankton occur on the first two depths of the reservoir.
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Myślą przewodnią artykułu jest diagnoza czynników wpływających na tworzenie się tak zwanych nowych klas próżniaczych oraz pokazanie struktury zawodów uznawanych przez społeczeństwo polskie za klasy próżniacze. Ideą przedstawionych treści jest ukazanie historycznych uwarunkowań powstawania klas próżniaczych oraz teoria klas próżniaczych rozpatrywana w kategoriach uwarstwienia społecznego. Jeden z obszarów badań stanowiło teoretyczne ujęcie stratyfikacji społecznej. Szczególny nacisk autor położył na strukturyzację zawodów w odniesieniu do skali prestiżu w Polsce, w tym również pozycji zawodu żołnierza.
XX
The purpose of this article is to diagnose the factors affecting the formation of the so-called idle classes, and to show the structure of professions recognized by the Polish society as an idle class, including the profession of a soldier. Referring to the sources of cognitive phenomena should emphasize its historical context. The formation of idle class has its origins along with creating the primitive forms of social differentiation. This institution is an effect of stratification and has a permanent place in the coexistence of groups, classes and social units. In order to fully understand the topic, the question of social inequality in theoretical was presented, as well as structuring the competition for the prestige scale in Poland.
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Artykuł prezentuje socjologiczną analizę pojęcia ciała i procesu medykalizacji życia społecznego. Autorka przyjmuje założenie, że wokół ciała został wytworzony swoisty porządek aksjo-normatywny, który determinuje zachowania społeczne w sferze zdrowia i estetycznego doświadczenia ciała. W tekście dowodzi, że we współczesnych społeczeństwach zachodnich ciało jest kapitałem i służy jako narzędzie stratyfikacji społecznej. W rynkowej strategii dbania o ciało aktywny udział bierze medycyna. Jednostki, refleksyjnie tworząc biografię, czynią ciało osią konstrukcyjną swej tożsamości. Proces uzależniania się społeczeństw od systemu medycznego nosi nazwę medykalizacji. Medycyna nasyca społeczeństwo typowymi dla siebie wartościami i wyznacza normy realizacji ideałów zdrowia.
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This paper describes shaping of the temp. and oxygen profiles in the Solina reservoir in the 2000 yr. Based on six characteristic stations located in the reservoir the results obtained in the period being analyzed and in the previous year were compared. Serious oxygen deficiencies were obsreved in almost every measuring point during the period of research. This can be a sign of proceeding eutrophication in the Solina reservoir, but the load of nutrients is still acceptable and does not lead to an accelerated eutrophication
PL
Omówiono kształtowanie się stosunków termiczno-tlenowych w zbiorniku Solińskim w 2000 r. Na postawie badań przeprowadzonych w 6 charakterystycznych punktach zbiornika dokonano oceny stratyfikacji i porównania z e stanem w latach ubiegłych. Stwierdzono znaczne niedotlenienie wód warstw przydennych, będące prawdopodobnie wynikiem wzrostu stężenia czynników biogennych w hypolimionie. Nie stwierdzono jednak przyspieszonej eutrofizacji.
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W artykule omówiono czynniki warunkujące uzyskanie pożądanego rozkładu temperatury w zbiornikach akumulujących ciepło, przedstawiono przykładowe rozwiązania konstrukcyjne.
EN
Factors influence the proper stratification in the storage tanks. Selected constructional solutions of hot water storage tanks in solar installations.
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In this paper we prove two fundamental lemmas of sub-Pfaffian geometry which are counterparts of Lemmas A and B for subanalytic sets [4]. We use a generalized version of the Tangent Mapping Theorem [2], following our program announced in [11].
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