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Spectacular accidents at sea which have happened for a few last years show that hull structures of contemporary sea-going ships are not perfect and must be systematically improved. Fatigue strength is one of the groups of strength problems which affect design of contemporary ship’s structures and greatly contribute in their improvement process. In this paper several approaches to estimation of fatigue life of hull structural elements are presented. In practice the some approaches based on nominal stresses, „hot spot” stresses or notch stresses which constitute the basis for fatigue life determination by using σ-N design curves are applied. In this paper the existing proposals have been critically analyzed and their drawbacks (often hidden) presented
This paper presents some aspects of technical preparation of production of inland waterways ship of combined structure contained partly: classical structures (bow and stern part) and sandwich panel structure. Due to prototype character of inland waterways ship structure it was decided to define a new subdivision of shipbuilding process into phases and create new classification principles if constructional and technological documentations
The presented work is a contribution to discussion on usefulness of application of measurement instrumentation used on sea-going ships for energy measurement and scientific research purposes. Contemporary sea-going ships are equipped as a rule with up-to-date measurement instrumentation usually based on electronic data processing and computer technique. These authors have made many times use of such instruments in their research work. This way it was not necessary to install any special instruments, that significantly reduced measurement cost. In such cases to obtain a sufficient accuracy of measurements constitutes a crucial problem. In this paper was presented an analysis of measurement errors of some operational parameters of ship and its main propulsion system, elaborated within the frame of the KBN research project no. 9 T12D 033 17. Results of the analysis confirm usefulness of the standard measurement instrumentation installed on ships, and its sufficient accuracy
Participation of superoxide anion and hydroxyl radical as well as lipoxygenase (LOX) activity and chemiluminescence in the development of grey mould on ,poinsettia leaves of the cvs.: Coco White - moderately resistant and Malibu Red sceptible to Botryotinia fuckeliana (B. cinerea) were investigated. In both poinsettia cultivars, the level of superoxide anion radical increased with the disease, development. On later dates following inoculation, the content of O₂‧₋ in the diseasedd leaf areas of the susceptible cultivar was 2 - fold larger than in grey mould symptom areas of the moderately resistant cultivar. The postinfection generation of a strongly reactive hydroxyl radical was found in the cultivar susceptible to the pathogen. The level of ‧₋ OH in the last hours after inoculation 10 fold higher in grey mould spots than in healthy senescing leaves of that cultivar. The activity of LOX exhibited opposite tendencies of changes in the both genotypes examined after the infection. In the first hours after inoculation, the e activity was Low, whereas after 3nd day it significantly increased in diseased areas and in their surroundings. However, in the moderately resistant cultivar activity of lipoxygenase thoughout the first 3 days of the disease activity was relatively high and then decreased. Poinsettia leaves infected with B. cinerea d chemiluminescence. Kinetics and the intensity of ultraweak chemiluminescence depended on the cultivars of poinsettia and on the degree of the disease development.The postinfection increase of chemiluminescence was particularly visible in the zone surrounding diseased areas in the susceptible cultivar.
A new model humic acid (HA) have been synthetized from 5-hydroxy-1,4-naphthoquinone (juglone, J), an allelopathic compound occuring in leaves, nut shells, exsudates of roots and barks of Juglans genera. Aqueous solutions of J were autooxidised at different pH 6-10 with mineral matrices: bentonite, glass and silica. The very slow autooxidation reaction was monitored by means of chemiluminescence (CL) imaging and kinetics supported by a highly sensitive CCD camera Molecular Light Imager. In the course of autooxidation that lasted three weeks, an extremely low-intensity of CL was detected The reaction liquid was further treated according to the IHSS protocol to isolate humic acid fractions. Elemental analysis, UV-VIS and FTIR absorption spectra as well as fluorescence excitation and emission spectra were measured to characterise this new HA.
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