Ordered droplet structures at the liquid crystal surface and elastic-capillary colloidal interactions

We demonstrate a variety of ordered patterns, including hexagonal structures and chains, formed by colloidal particles (droplets) at the free surface of a nematic liquid crystal (LC). The surface placement introduces a new type of particle interaction as compared to particles entirely in the LC bulk. Namely, director deformations caused by the particle lead to distortions of the interface and thus to capillary attraction. The elastic-capillary coupling is strong enough to remain relevant even at the micron scale when its buoyancy-capillary counterpart becomes irrelevant.Comment: 10 pages, 3 figures, to be published in Physical Review Letter

Effective interactions of colloids on nematic films

The elastic and capillary interactions between a pair of colloidal particles trapped on top of a nematic film are studied theoretically for large separations $d$. The elastic interaction is repulsive and of quadrupolar type, varying as $d^{-5}$. For macroscopically thick films, the capillary interaction is likewise repulsive and proportional to $d^{-5}$ as a consequence of mechanical isolation of the system comprised of the colloids and the interface. A finite film thickness introduces a nonvanishing force on the system (exerted by the substrate supporting the film) leading to logarithmically varying capillary attractions. However, their strength turns out to be too small to be of importance for the recently observed pattern formation of colloidal droplets on nematic films.Comment: 13 pages, accepted by EPJ

Melting of 2D liquid crystal colloidal structure

Using video microscopy, we investigated melting of a two-dimensional colloidal system, formed by glycerol droplets at the free surface of a nematic liquid crystalline layer. Analyzing different structure correlation functions, we conclude that melting occurs through an intermediate hexatic phase, as predicted by the Kosterlitz-Thouless-Halperin-Nelson-Young(KTHNY) theory. However, the temperature range of the intermediate phase is rather narrow, <1°C, and the characteristic critical power law decays of the correlation functions are not fully developed. We conclude that the melting of our 2D systems qualitatively occurs according to KTHNY, although quantitative details of the transition scenario may partly depend on the details of interparticle interaction

Application of german solutions in odour annoyance evaluation in Poland

Zgodnie z definicją WHO [20], zdrowie to nie tylko całkowity brak choroby, czy kalectwa, ale także stan pełnego, fizycznego, umysłowego i społecznego zadowolenia. Zapachy natomiast powodować mogą dyskomfort, irytację, bóle głowy, mdłości, problemy z koncentracją, brak apetytu, bezsenność czy stres [1, 11]. Dlatego też uciążliwość zapachową można zdefiniować jako szkodliwą dla zdrowia poprzez powtarzające się odczuwanie niechcianych zapachów. Pomimo przeprowadzonych badań związanych z oceną uciążliwości zapachowej Polsce nie udało się do tej pory stworzyć uregulowań prawnych dotyczących tego zagadnienia [10, 12, 14, 15]. W wielu krajach na całym świecie istnieją normy dotyczące zapachów (Niemcy, Holandia, Kanada, Australia). Funkcjonuje europejska norma EN 13725 dotycząca określenia stężenia zapachu metodą olfaktometrii dynamicznej, a także jej polska wersja PN EN 13725. Normy te dotyczą jednakże emisji odorów. Do tej pory, natomiast, nie udało się na skalę europejską wprowadzić podobnych standardów odnośnie badan imisji zapachu i jakości powietrza atmosferycznego.Poland has not managed to create regulations on the odour nuisance assessment in spite of studies related to this issue. In many countries around the world e.g. in Germany, Netherlands, Canada, Australia, there are standards relating to odours. For several years, operates the European standard EN 13725 for the determination of odour concentration by dynamic olfactometry, and its Polish version PN-EN 13725. However, these standards relate to odour emission. So far, there are no similar standards for odour in ambient air (odour imission) and air olfactory quality assessment on a European scale. The legal basis for air quality in Germany is the Act on Protection of At-mospheric Air (German BImSchG: Bundes-Immissionsschutzgesetz). According to it (§ 3 (1)) deterioration of the environment due to pollution, which, because of the nature, size and duration, can cause harm, serious injury or annoyance to the public. Only under this Act a odour nuisance as environment pollution may be viewed. Each plant obtaining licenses for the operation or control of already existing plants is obliged to assess the extent to which the possible nuisance can be considered as serious. So guidelines for "Odour in the air" were developed. In these guidelines, the methods of dealing in relation to immission odour measurement methods and requirements for air olfactory quality are presented: inter alia, the limits of recognized odours in the areas around the industrial plants. The limit values were obtained basing on carried out measurements, comparative tests of the impact and odour frequency and level assessed on the basis of surveys in accordance with VDI 3883. According to GOAA (Guideline on Odour in Ambient Air), the smell can be characterized by its type, the level of feelings - above the threshold of recognition, and through the so-called 'odour hour'. Lack of regulation and standardized terminology relating inter alia to odour measurements in the field is definitely a basic limitation when trying to apply methods of odour assessing in Poland. Therefore, there is a need to clarify the concepts of 'odour imission' (odour in ambient air) and 'survey'. The first of them allows an assessment of frequency of the odour occurrence, is also called 'field research / inspections / measurements'. However, as a 'survey' (question-naires) is defined odor nuissance assessment. The term 'field research' refers to the total assessment of odour with both the imission measurements and questionnaires. Currently, the only way to carry out research in and around a potential odour emission source is the good will of the representatives of the plant. However, the vast majority of traders fear field measurements, since the results of measurements would suggest a potential need for changes and improvements in technology of the industrial plant, which undoubtedly would impose a large financial outlay. Further restrictions apply to conduct research themselves. On one hand, the measurements do not require any complicated or expensive equipment. On the other, are indispensable to the people creating the panel, who should be trained and then perform measurements, which require financial resources. Another problem of a formal nature, is a law on the protection of per-sonal data. Impossible or difficult access to the population database of potential respondents from the area could lead to a significant reduction in the quality of research results and their lack of credibility. However, taking into account the very complex nature of the problem of odour nuisance, and particularly the influence of 'no olfactory' factors, odour evaluation process should be expanded just a survey. Thus, in this study modifications to the German methodology have been done in order to develop evaluation process of the air olfactory quality assessment. It has been concluded that the legislation related to odours should be introduced in Poland in order to improve the evaluation of the problem and finding the optimal deodoration solution

A concept for reconstruction of the Niedów barrage on the Witka river

Katastrofa budowlana zapory ziemnej przegradzającej dolinę rzeki Witki w km 2+800 jej biegu i tworzącej zbiornik retencyjny spowodowała konieczność wybudowania nowej budowli spełniającej przepisy techniczne i zapewniającej dostawę wody dla elektrowni „Turów” i miasta Bogatyni. W artykule przedstawiono wyniki analiz poprzedzających prace projektowe nowej budowli oraz cztery koncepcje różniące się konstrukcją zapory i urządzeń upustowych oraz zasadami gospodarki wodnej na zbiorniku.A building disaster in an earth dam forming a reservoir in the valley of the Witka river (at km 2+800) has made it necessary to build a new structure compliant with technical regulations and ensuring the supply of water to the Turów power plant and the town of Bogatynia. The article presents the results of analyses carried out prior to work on designing the new structure, and four concepts which differ in terms of both the structural design of the dam and sluice devices, and the principles for water management on the reservoir

Application of GIS technique for pm2.5 and pm10 concentrations spatial analysis in the province of lower silesia

Zmienność w czasie i przestrzeni danych stanowi kluczowy element różnych zjawisk zachodzących w środowisku przyrodniczym. W celu zbadania zmienności buduje się bazy danych, w których jedną z cech jest lokalizacja. W dobie automatyzacji i informatyzacji bazy danych to niezbędny element funkcjonowania wielu instytucji państwowych oraz firm prywatnych. Problematyczne wydaje się być przedstawienie informacji zawartych w bazach w taki sposób, by zmiany przed-stawione za pomocą liczb były łatwe i szybkie w analizowaniu. Z pomocą przychodzą rozwiązania technik GIS (z ang. Geographic Information System), stosowane obecnie na szeroką skalę w wielu branżach m.in. w transporcie, budownictwie, energetyce oraz w inżynierii i ochronie środowiska [1÷8]. Celem niniejszej pracy była wizualizacja i analiza przestrzenna danych dotyczących zanieczyszczenia powietrza atmosferycznego pyłem zawieszonym PM10 i PM2.5 na terenie województwa dolnośląskiego przy zastosowaniu techniki GIS.Variability of data in time and space is a key element of the different phenomena occurring in the natural environment. In order to investigate the variability a databases in which one of the features is the location are built up. In the era of automation and computerization the databases are an essential element for the functioning of many public institutions and private companies. Problematic seems to be to present the information in databases in such a way as to amendments submitted by the numbers were easy and quick to analyze. In such a case the GIS technique can be helpful. The method of implementation of spatial analysis using ArcGIS soft-ware package was presented. It consisted of obtaining data on concentrations of pollutants, processed for the purposes of the program, the appropriate data management, analysis and graphical presentation of results. There were used functions that were needed to create the area and point type map layers. By use of the area type layers, zones according to which the concentrations classification was conducted. And with a point type layers measurement points used in the study were presented. For each layer is assigned the characteristics of the resource database, which allowed their subsequent interpretation by the spatial analysis. By combining point-type layer with polygons characteristics for the relevant areas was averaged. Ability to set the layer properties has allowed for classification and presentation of data assigned to them. In this study spatial analysis were conducted to show the possibility of using geoinformation techniques in monitoring of concentrations of selected air pollutants (PM10 and PM2.5). Developed data of measurements of concentrations of PM10 and PM2.5 from the beginning of 2009 till September of 2010 were made available by the Regional Inspectorate for Environment Protection in Wroclaw. Using this set of data it was possible to present and to characterize air pollution by particulate matter PM10 and PM2.5 in the Lower Silesia province. It was observed that the zones characterized by the highest levels in selected averaging periods (monthly and annual) were: District Kłodzko, Wałbrzych, the city of Legnica and Wrocław agglomeration. In 2009, the observed average concentrations exceeded the limit of PM10 (40 ?g/m3) in the Kłodzko. The concentrations of PM10 in the range from 30 to 40 ?g/m3 near Legnica, district of Wałbrzych and Wrocław agglomeration were observed. In 2010, the concentrations of PM10 in ambient air over three mentioned areas has been exceeded the limit values. In the case of PM2.5 annual average concentration allowed value (25 ?g/m3) was exceeded in the district of Wałbrzych and Wrocław agglomeration. It was also examined the impact of volcanic eruption of Eyjafjallajökull in Iceland, which took place on April, 14th (2010), on air quality in the Lower Silesia province. The changes in concentrations of PM10 and PM2.5 for 14 and 18 of April 2010 were studied. Prepared maps indicated that the PM 2.5 concentrations four days after the eruption, when the air space for air transportation in most countries in Europe, including Polish, was closed, over most concerned areas were lower compared with April 14th 2010. For a fraction of PM10 there were no significant changes in concentrations in Lower Silesia province

The Conditions and Requirements Necessary for the Proper Functioning of the Olfactometric Laboratory

A characteristic feature of many chemicals, also emitted during industrial processes, is the smell, which is a matter of individual perception, depending on the individual features. Odor emission significantly influences on the quality of people life and can significantly decrease the quality of the environment. Over the world there is used several methods to assess odor air quality including analytical chemistry methods, dynamic olfactometry and static dilutions, field inspections, surveys and modeling. In Poland, the standardization document regarding to odor is the PN-EN 13725:2007 standard "Air Quality. Determination of odor concentration by dynamic olfactometry." that includes a description of the methodology of the odor concentration measuring and sets out the requirements necessary to ensure the quality of olfactometric research. In order to determine odor emissions, it is necessary to determine the odor concentration, which is expressed in European odor units per cubic meter (ouE/m3). It is the amount of odorant vaporized in a volume of 1 m3 of inert gas that at standard conditions is sensed by half of representative group exposed to odorant. Due to the nature of olfactometric research in that the main role of odor sensor fully plays human nose in Olfactometric Laboratory is particularly important to take care of the quality and precision of the measurements. It should be provided a pleasant working environment for the evaluation team and ensured the reliability of its members through appropriate incentives, training in the methodology of measurements and the applicable rules, and careful selection by the use of the certified reference material. To ensure the quality of the measurements in the Olfactometric Laboratory it is necessary to ensure measurement devices that require periodic controls and calibration. To ensure accuracy and precision criteria must be also performed compliance testing to the laboratory and inter-laboratory tests