Nanoscale Visualization of Elastic Inhomogeneities at TiN Coatings Using Ultrasonic Force Microscopy

Ultrasonic force microscopy has been applied to the characterization of titanium nitride coatings deposited by physical vapor deposition dc magnetron sputtering on stainless steel substrates. The titanium nitride layers exhibit a rich variety of elastic contrast in the ultrasonic force microscopy images. Nanoscale inhomogeneities in stiffness on the titanium nitride films have been attributed to softer substoichiometric titanium nitride species and/or trapped subsurface gas. The results show that increasing the sputtering power at the Ti cathode increases the elastic homogeneity of the titanium nitride layers on the nanometer scale. Ultrasonic force microscopy elastic mapping on titanium nitride layers demonstrates the capability of the technique to provide information of high value for the engineering of improved coatings

Plants in aquatic ecosystems: current trends and future directions

Aquatic plants fulfil a wide range of ecological roles, and make a substantial contribution to the structure, function and service provision of aquatic ecosystems. Given their well-documented importance in aquatic ecosystems, research into aquatic plants continues to blossom. The 14th International Symposium on Aquatic Plants, held in Edinburgh in September 2015, brought together 120 delegates from 28 countries and six continents. This special issue of Hydrobiologia includes a select number of papers on aspects of aquatic plants, covering a wide range of species, systems and issues. In this paper we present an overview of current trends and future directions in aquatic plant research in the early 21st century. Our understanding of aquatic plant biology, the range of scientific issues being addressed and the range of techniques available to researchers have all arguably never been greater; however, substantial challenges exist to the conservation and management of both aquatic plants and the ecosystems in which they are found. The range of countries and continents represented by conference delegates and authors of papers in the special issue illustrate the global relevance of aquatic plant research in the early 21st century but also the many challenges that this burgeoning scientific discipline must address

Differentiation of macrophytes in the reference conditions of different river types in Poland

Badania przeprowadzono na terenie Polski niżowej, z uwzględnieniem odcinków referencyjnych wszystkich typów rzek nizinnych, które zostały wydzielone w naszym kraju na potrzeby Ramowej Dyrektywy Wodnej. Badania terenowe zostały wykonane w okresie od czerwca do września w latach 2003–2007. Badania wykonywano wg makrofitowej metody oceny rzek, na podstawie których obliczono makrofitowy indeks rzeczny MIR, całkowite pokrywanie przez rośliny, udział różnych grup ekologicznych oraz podstawowe wskaźniki różnorodności [liczba gatunków, wskaźnik Shannona-Wienera, równomierności, Simpsona i dominacji]. Oprócz badań biologicznych, na każdym stanowisku przeprowadzono ocenę hydromorfologiczną rzek metodą River Habitat Survey [RHS]. Na wszystkich badanych stanowiskach wykonano także analizy fizykochemicznych cech wody z wykorzystaniem standardowych metod. Analizy te umożliwiły wyodrębnienie czterech makrofitowych typów rzek. Są to: rzeki organiczne, małe rzeki krzemianowe z piaszczystym materiałem dna, małe rzeki krzemianowe z podłożem kamienistym oraz duże rzeki krzemianowe. Porównując obliczone wskaźniki makrofitowe, wykazano, że wskaźniki stanu ekologicznego MIR oraz wskaźniki dominacji miały podobne wartości w różnych typach rzek, natomiast indeksy różnorodności biologicznej oraz całkowite pokrywanie przez makrofity różniły się istotnie między typami. Największą różnorodność gatunkową zaobserwowano w rzekach organicznych, natomiast najmniejszą - w małych rzekach krzemianowych o piaszczystym materiale dna.Presented analyses were aimed to describe macrophyte development in pristine lowland rivers and to show their variation among various stream types. The study was based on a country-wide survey of Poland with a dataset of 642 sites situated on 367 water courses. Surveyed rivers covered the whole lowland area of Poland and every potential reference site has been checked. During the survey all existing lowland river types were investigated in accordance to WFD requirements. The reference sites were selected from the whole database. Reference conditions were defined using four criteria: catchment land use, hydromorphological features, water quality and biological assessment. Based on chosen criteria, the database of reference lowland rivers included 40 sites. To classify plant data, twoway indicator species analysis Twinspan was used, which resulted in distinguishing 4 evident endclusters which differed in plant composition. These were: organic rivers and 3 types of siliceous rivers (small with sandy substrate, small with stony substrate and large rivers). For each of the revealed river types several macrophyte metrics were calculated. The numerical index MIR [Macrophyte Index for Rivers] did not significantly differ between river types while four diversity metrics: species richness, Shannon index, evenness and Simpson index differed significantly between river types. Moreover, the share of different structural forms of macrophytes was also diversified between river types

Assessment of sources of uncertainty in macrophyte surveys and the consequences for river classification

The application of macrophytes in freshwater monitoring is still relatively limited and studies on their intercalibration and sources of variation are required. Therefore, the aim of the study was to compare selected indices and metrics based on macrophytes and to quantify their variability. During the STAR project, several aspects influencing uncertainty in estimation of the ecological quality of river were assessed. Results showed that several metrics based on the indicative value of plant species can be used in evaluation of the ecological status of rivers. Among estimated sources of variance in metric values the inter-surveyor differences had the lowest effect and slightly stronger were the influences of temporal variation (years and seasons) and shading. The impact of habitat modification was the most important factor. Analysis showed that some of macrophyte-based metrics (notably MTR and IBMR) are of sufficient precision in terms of sampling uncertainty, that they could be useful for estimating the ecological status of rivers in accordance with the aims of the Water Framework Directive

Local wettability modification by thermochemical nanolithography with write-read-overwrite capability

© 2007 American Institute of Physics. The electronic version of this article is the complete one and can be found at: http://dx.doi.org/10.1063/1.2816401DOI: 10.1063/1.2816401The wettability of a thin polymer film was modified twice by thermochemical nanolithography. By means of a first local chemical modification induced by an atomic force microscope tip heated to 110±20 °C, hydrophilic patterns are written over an originally hydrophobic polymer surface. By further heating to 190±20 °C, a second chemical modification reverses the local wettability change introduced by the first chemical modification. This write-read-overwrite capability can be particularly useful in the design of complex nanofluidic devices