Long-Term Changes in the Course of Ice Phenomena on the Oder River along the Polish–German Border

Ice phenomena are a major component of the hydrological regime of east-central and northern European rivers. However, their occurrence disturbs inland water transportation, particularly affecting the major rivers of the Central European Plain that are part of Europe’s international waterways. The Oder is one of these rivers, and is located on the boundary between the much warmer and the much colder part of the temperate climatic zone. This makes the course of ice phenomena on the river difficult to predict. The main purpose of this work is to document and analyse the dynamic of changes occurring for over 60 years (1956–2015) in the ice phenomena of a river that demonstrates a transitional ice regime. It was found that the duration of all ice phenomena decreased (by up to 0.58 days·year^?1) and so did the duration of ice cover (by up to 0.46 days·year^?1). The rates and trends of the two parameters were, however, different in different parts of the lower stretch of the river. This fact is especially important in the context of climate changes whose characteristics include an increased incidence of extreme weather situations, both meteorological and hydrological. There was also found to be a strong correlation (R² from 0.69 to 0.81) between the duration of ice phenomena and the mean air temperature in winter (December to February) and a much weaker correlation between the duration of ice phenomena and the NAO index (R² from 0.42 to 0.48). Such a little correlation of ice phenomena with NAO is likely to result from the pollution of the Oder River (in particular in the second half of the twentieth century) and icebreaking operations on the river.

     

A learning-based colour image segmentation with extended and compact structural tensor feature representation

In this paper a novel Tensor-Based Image Segmentation Algorithm (TBISA) is presented, which is dedicated for segmentation of colour images. A purpose of TBISA is to distinguish specific objects based on their characteristics, i.e. shape, colour, texture, or a mixture of these features. All of those information are available in colour channel data. Nonetheless, performing image analysis on the pixel level using RGB values, does not allow to access information on texture which is hidden in relation between neighbouring pixels. Therefore, to take full advantage of all available information, we propose to incorporate the Structural Tensors as a feature extraction method. It forms enriched feature set which, apart from colour and intensity, conveys also information of texture. This set is next processed by different classification algorithms for image segmentation. Quality of TBISA is evaluated in a series of experiments carried on benchmark images. Obtained results prove that the proposed method allows accurate and fast image segmentation.     

The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition

Journal of Materials Science - The superionic α???β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and...     

An exploratory study of the relationship between construction workforce physical strain and task level productivity

The monitoring of construction workforce physical strain can be a valuable management strategy in improving workforce productivity, safety, health, and quality of work. Nevertheless, clear relationships between workforce performance and physical strain have yet to be established. An exploratory investigation of the relationship between task level productivity and physical strain was conducted. Nine participants individually performed a four-hour simulated construction task while a wearable physiological status monitor continuously assessed their physiological condition. Heart rate, relative heart rate, and breathing rate were utilized as predictors of physical strain, and task level–single factor productivity was used as an index of productivity. Numerous regression models were generated using the collected data. This investigation initially unsuccessfully attempted to establish a relationship between physiological condition and productivity at the individual worker level. However, an analysis of the regression models showed that there is a relationship between productivity and either heart rate or relative heart rate at the group level, and that this relationship is parabolic. Breathing rate was proved to not be a significant predictor of productivity. Research results significantly improve understanding of the relationship between work physiology and task productivity. Researchers and practitioners may use the tested monitoring devices, analysis methods, and results to design further applied studies and to improve workforce productivity.     

Strategies for overlapping dependent design activities

Overlapping activities that are traditionally performed in a sequential manner can significantly reduce project delivery times. Overlapping, however, should be approached in a systematic manner to reduce the costs and risks. Information gathered from sector‐based case studies and from the manufacturing domain suggest a formalised framework for identifying overlapping opportunities and strategies can be successfully implemented for infrastructure projects. This framework considers activity characteristics, such as evolution of upstream information and sensitivity of downstream activities to changes in upstream information, to identify appropriate overlapping strategies. Overlapping strategies, such as early freezing of design criteria, overdesign, and early release of preliminary information, are selected based on activity characteristics. These strategies operate either by speeding up the evolution of upstream information or by reducing the sensitivity of downstream activities. By aligning overlapping strategies with activity characteristics, project managers can make better decisions on when and how much to overlap sequential activities to reduce overall project delivery time.     

High temperature monoclinic-to-tetragonal phase transition in magnesium doped lanthanum ortho-niobate

Magnesium doped lanthanum ortho-niobate (La_0.98Mg_0.02NbO₄) was prepared by the molten salt synthesis method. X-ray diffraction and dilatometry methods were used to study high temperature behavior of the ceramic material. Special attention was paid to the phase transition between the monoclinic and tetragonal phases. The values of spontaneous strain on the basis of unit cell parameter, obtained by Rietveld refinement, have been calculated as well as Landau order parameter. The thermal expansion coefficient (TEC) of La_0.98Mg_0.02NbO₄ was determined to be 12×10^?6 1/K and 8×10^?6 1/K below and above 500 °C, respectively.