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Abstract

This paper presents an analysis of environmental and technical conditions necessary for working out a possibly most favourable propulsion system for a two – segment passenger ship intended for navigation between Berlin and Kaliningrad. There are presented various types of propulsion systems for small ships as well as analyzed their possible applications and consequences. In this work there were taken into account system’s reliability, efficiency, dimensions, mass and costs of manufacturing, assembling and possible replacing the system components as well as an impact on maneuverability and natural environment. With taking into account the above mentioned criteria it was finally found that the diesel-hydraulic system fitted with two azimuthal ducted solid propellers is the most favourable. There are also presented a schematic propulsion and control diagram, three-dimensional arrangement drawing of system components as well as assembly drawing of the designed azimuthal propulsion system.

Abstract

A seaport is presented in this article as a system composed of various types of waterways. The author has defined relationships between port waterway system elements and conditions of safe operation of ships in port. Relationships were determined between the conditions of safe operation of ships and the parameters of the following port waterways: anchorage, fairways (approach and inner channels, port entrances), turning area and port basin. The identified relationships between port waterway system and conditions of safe ship operation provided a basis for formulating the objective function of waterway parameter optimization during port design. In practice, these relations were used to determine the parameters of the Outer Container Terminal being built in Świnoujście, where two optimization problems were to be solved:

  1. The optimization of approach channel parameters,
  2. The optimization of parameters of the port entrance, turning area and port basin.
The Outer Container Terminal in Świnoujście is expected to handle ocean-going ships with a length overall Lo = 400 m, and its projected capacity is estimated at 1.5 million TEU per year, a figure that can be doubled in the future.

Abstract

The paper presents a research stand being a diagnostic model of radial lip seals used, among others, on crankshafts of piston combustion engines in order to identify the correctness of their operation. The possibility of determining the technical condition of lip seals on the basis of the proposed coefficient of correctness of operation has been described. The basic features of seals influencing their correctness of operation were also described, along with examples of determining the durability limits of lip seals. A modified version of the friction node of the T-02 four-ball apparatus is presented. It allows to check the correctness of sealing lips operation as well as to test the compatibility between the steel shaft, sealing lip and sealed lubricating oil. It was shown that the test results con-firmed the usefulness of the hypothesis that the quality of oil affects the durability of sealing lips and their coefficient of correctness. Additionally, attention was paid to the possibility of analyzing the pumping effect affecting the transition of the seal-shaft system from the state of partial suitability S2 to the state of full suitability S1 or to the state of unfitness S3, and because the change in the state of such a system is random, it requires a probabilistic analysis.

Abstract

In this study, the dynamic characteristic problem of riser structure with complex pre-stress distribution is investigated. At first, the differential equation of the riser structure with complex pre-stress distribution is derived. The analytical expression of the free vibration of a riser structure with complex pre-stress distribution is discussed by using the orthogonal property of the trigonometric series. A top-tensioned riser (TTR) for example, the influences of the amplitude and direction of complex pre-stress on natural frequency and mode shape characteristics are compared. This study provides a new method for addressing the riser structure response problem with complex loading.

Abstract

The tree species composition can influence the dynamics of herbaceous species and enhance the spatial heterogeneity of the soil. But there is very little evidence on how both overstorey structure and soil properties affect the spatial variation of the herb layer. The aim of this study is to evaluate the factors of the soil and overstorey structure by which it is possible to explain the fine-scale variation of herbaceous layer communities in an Eastern European poplar-willow forest. The research was conducted in the “Dnipro-Orils’kiy” Nature Reserve (Ukraine). The research polygon (48°30′51″N, 34°49″02″E) was laid in an Eastern European poplar-willow forest in the floodplain of the River Protich, which is a left inflow of the River Dnipro. The site consists of 7 transects. Each transect was made up of 15 test points. The distance between rows in the site was 3 m. At the site, we established a plot of 45×21 m, with 105 subplots of 3×3 m organized in a regular grid. The adjacent subplots were in close proximity. Vascular plant species lists were recorded at each 3×3 m subplot along with visual estimates of species cover using the nine-degree Braun-Blanquet scale. Within the plot, all woody stems ≥ 1 cm in diameter at breast height were measured and mapped. Dixon’s segregation index was calculated for tree species to quantify their relative spatial mixing. Based on geobotanical descriptions, a phytoindicative assessment of environmental factors according to the Didukh scale was made. The redundancy analysis was used for the analysis of variance in the herbaceous layer species composition. The geographic coordinates of sampling locations were used to generate a set of orthogonal eigenvector-based spatial variables. Two measurements of the overstorey spatial structure were applied: the distances from the nearest tree of each species and the distance based on the evaluation of spatial density of point objects, which are separate trees. In both cases, the distance matrix of sampling locations was calculated, which provided the opportunity to generate eigenvector-based spatial variables. A kernel smoothed intensity function was used to compute the density of the trees’ spatial distribution from the point patterns’ data. Gaussian kernel functions with various bandwidths were used. The coordinates of sampling locations in the space obtained after the conversion of the trees’ spatial distribution densities were used to generate a set of orthogonal eigenvector-based spatial variables, each of them representing a pattern of particular scale within the extent of the bandwidth area structured according to distance and reciprocal placement of the trees. An overall test of random labelling reveals the total nonrandom distribution of the tree stems within the site. The unexplained variation consists of 43.8%. The variation explained solely by soil variables is equal to 15.5%, while the variation explained both by spatial and soil variables is 18.0%. The measure of the overstorey spatial structure, which is based on the evaluation of its density enables us to obtain different estimations depending on the bandwidth. The bandwidth affects the explanatory capacity of the tree stand. A considerable part of the plant community variation explained by soil factors was spatially structured. The orthogonal eigenvector-based spatial variables (dbMEMs) approach can be extended to quantifying the effect of forest structures on the herbaceous layer community. The measure of the overstorey spatial structure, which is based on the evaluation of its density, was very useful in explaining herbaceous layer community variation.

Abstract

Soil is a sensitive ecological factor. Biodegradable materials from the environment can also be used to deal with serious ecological problems. Soil affecting by remediation medium - garden compost - was analysed for toxic cadmium (Cd) in terms of environmental protection. The objective of this research was to analyse soil and compost at foothill locality of the Tribeč Mountains (Southwestern Slovakia) in the years 2015−2017 to determine Cd contents in soil and compost, pH and to assess Cd bioavailability. The analyses were carried out using the Atomic Absorption Spectrometry with seven-step Selective Sequential Extraction methods. The results obtained were evaluated statistically using the SAS 9.4 software method by Spearman’s correlation coefficient. The results showed that Cd contents in soil had reached 2.96 mg kg−1 and soil with compost (the ratio 1:1) 2.71 mg kg−1 dry matter. Cd contents in the soil exceeded maximum allowed limit of 196%. And deceased by 25% after adding compost. The pH in soil with compost varied from 6.78 to 7.98. The pH prevented the mobility of Cd about 8.3% in average. Statistical dependence was high, which was demonstrated for relationship between Cd in soil, pH and compost. Available Cd forms in soil were 53.3% and soil with compost were 45% in average. The garden compost as a remediation medium reduced Cd bioavailability.

Abstract

The Turkish Merchant Shipping Industry has recently witnessed an increasing awareness of the importance to minimize environmental pollution and fuel oil consumption. Together with certain non-governmental organizations and media concerns about environmental protection, the International Maritime Organization (IMO) has been strict on controlling undesirable effects on the environment and, consequently, forcing shipping companies to minimize their emissions. Besides, today’s highly advanced technology companies over the world have developed various innovative systems that can be utilized to minimize carbon emission, thus giving assurance to relevant investors that their investments are most likely to turn out well with a considerable financial gain in the short or long term. Despite all such favorable developments, in a general look, shipping companies seem reluctant in making use of technologies providing efficiency in energy consumption. This reluctance has eventually brought about the term “Energy Efficiency Gap”. This research conducts a questionnaire, created by Acciaro et al. [1], among the shipping companies in Turkey. 20 respondent companies, who represent 26 percent of the Turkish owned merchant marine fleet of over 1000 gross tonnage in terms of deadweight cargo capacity, participated in the research. The Pearson correlation analysis was used, and interpretations were made according to the obtained statistical values. The aim of the research was to identify reasons and points restraining the use of new technologies regarding energy efficiency, as well as to develop proposals for the innovators in this field about how to overcome this handicap concerning technical and managerial aspects of gaining energy efficiency.

Abstract

The article aims at defining and analysing the energy loss coefficients in design solutions of rotating displacement machines, with a piston machine as an example. The energy losses observed in these machines include mechanical loss, volumetric loss, and pressure loss. The scale and relations between these losses in different machines depend on machine design and manufacturing quality, and on operating parameters. The operating parameters, in turn, which affect directly or indirectly the above losses depend on whether the machine works in pump or hydraulic motor regime. The article is also a contribution to the development of a library of ki coefficients which define the losses in displacement machines, as the knowledge about these coefficients makes it possible to assess fast and easily the energy efficiency of a machine or drive system at each point of its working area.

Abstract

The objective of the study is the presentation of the chemical properties of forest chernozems and the features of forest habitats developed on chernozems in south-eastern Poland. The assessment of the trophic status of chernozems was presented based on the Trophic Soil Index (SIG). Moreover, the paper presents the diversity of forest vegetation on chernozems. The research covered 15 plots from the habitat inventory performed for the Mircze and Strzelce Forest Districts (SE Poland). Habitat conditions were characterised on the research plots, with particular consideration of the soil and vegetation. The analysed soils were featured by the presence of thick humus horizons and the occurrence of calcium carbonate. High SIG values confirm the eutrophic status of the analysed soils. In general, fresh and wet habitats of broadleaved forests (Lśw and Lw), as well as fresh habitats of broadleaved upland forest (Lwyżśw) develop on chernozems in Poland. They are associated with multi-species broadleaved tree stands. The conducted research indicates that, in current environmental conditions, the potential plant community is oak-hornbeam forest with predominance of oak, hornbeam, and abundant admixtures of other broadleaved species. High trophic status of the analysed chernozems is confirmed by high bonitation of tree stands and richness of forest floor vegetation.

Abstract

This paper presents the main technical characteristics and working performances of coastal maritime surveillance radars, such as low-power High-Frequency Surface Wave Radars (HFSWR) and Over the Horizon Radars (OTHR). These radars have demonstrated to be a cost-effective long-range early-warning sensor for ship detection and tracking in coastal waters, sea channels and passages. In this work, multi-target tracking and data fusion techniques are applied to live-recorded data from a network of oceanographic HFSWR stations installed in Jindalee Operational Radar Network (JORN), Wellen Radar (WERA) in Ligurian Sea (Mediterranean Sea), CODAR Ocean Sebsorsin and in the German Bight (North Sea). The coastal Imaging Sciences Research (ISR) HFSWR system, Multi-static ISR HF Radar, Ship Classification using Multi-Frequency HF Radar, Coastal HF radar surveillance of pirate boats and Different projects of coastal HF radars for vessels detecting are described.

Ship reports from the Automatic Identification System (AIS), recorded from both coastal and satellite Land Earth Stations (LES) are exploited as ground truth information and a methodology is applied to classify the fused tracks and to estimate system performances. Experimental results for all above solutions are presented and discussed, together with an outline for future integration and infrastructures.