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Number of results: 11
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Abstract

The goal of the article is the description and analyze of the exclusions of the maritime carrier’s liability, regulated in international conventions, known as the Hague-Visby Rules and the Hamburg Rules. Their construction is basically different and indicates, that their creators had quite the opposite approach in the way of regulation of the negative scope of maritime carrier’s liability. In the article it has been compared each exclusion of liability in both conventions, especially with the consideration of the genuine differences with the carrier’s scope of liability. It has been analyzed the examples of the real cases, that have been ruled on the grounds of the maritime carrier’s liability. It has been also take a try to evaluate if the court’s sentence would be the same on the grounds of both conventions, or rather would be different.
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Abstract

The aim of the study was to find out whether carriers of new lethal mutation in SDE2 gene occur in the population of Polish Holstein-Friesian bulls. Eighty seven bulls were included in the analysis. Bulls were selected as having in the pedigree known carrier of SDE2 mutation (bull Mountain USAM000002070579). All bulls were diagnosed by PCR amplification of 524 bp fragment of SDE2 gene followed by digestion of Bcc I restriction enzyme. Heterozygotes (carriers) were confirmed by sequencing. Each new carrier was used to trace another potential carriers among its offspring available in Polish Holstein Bull Repository Database. Among 87 bulls, 50 new SDE2 carriers were found. The study has shown that mutation in SDE2 gene causing early embryo mortality is already transmitted to Polish Holstein-Friesian cattle. The results are sufficient to initiate the screening program to reveal new carriers and to avoid further spreading of SDE2 lethal mutation.
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Abstract

The application of waste heat from exhaust gas of ship’s main engines has become widely practiced as early as in the 1930s. Thus the increase of ship’s overall efficiency was improved. Nowadays all newly built ships of the 400 gross tonnage and above must have specified energy efficiency design index, which is a measure for CO2 emissions of the ship and its impact on the environment. Therefore, the design of waste heat recovery systems requires special attention. The use of these systems is one of the basic ways to reduce CO2 emissions and to improve the ship’s energy efficiency. The paper describes the ship’s heating systems designed for the use of waste heat contained in the exhaust gas of self-ignition engines, in which the heat carriers are respectively water vapor, water or thermal oil. Selected results of comparative exergy analysis of simplified steam, water and oil heating systems have been presented. The results indicate that the oil heating system is comparable to the water system in terms of internal exergy losses. However, larger losses of exergy occur in the case of a steam system. In the steam system, a significant loss is caused by the need to cool the condensate to avoid cavitation in boiler feed pumps. This loss can in many cases cause the negative heat balance of ship during sea voyage while using only the exhaust gas boilers.
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Abstract

Extracellular laccase produced by the wood-rotting fungus Cerrena unicolor was immobilised covalently on the mesostructured siliceous foam (MCF) and three hexagonally ordered mesoporous silicas (SBA-15) with different pore sizes. The enzyme was attached covalently via glutaraldehyde (GLA) or by simple adsorption and additionally crosslinked with GLA. The experiments indicated that laccase bound by covalent attachment remains very active and stable. The best biocatalysts were MCF and SBA-15 with Si-F moieties on their surface. Thermal inactivation of immobilised and native laccase at 80°C showed a biphasic-type activity decay, that could be modelled with 3- parameter isoenzyme model. It appeared that immobilisation did not significantly change the mechanism of activity loss but stabilised a fraction of a stable isoform. Examination of time needed for 90% initial activity loss revealed that immobilisation prolonged that time from 8 min (native enzyme) up to 155 min (SBA-15SF).
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Abstract

The influence of the refractory coating which is a mixture of silica flour and kaolin on the surface roughness of the plate castings produced using evaporative patterns had been considered in this work. The kaolin was used as a binder and ratio method was employed to form basis for the factorial design of experiment which led to nine runs of experiments. Methyl alcohol at 99% concentration was used as the carrier for the transfer of the coating to the surface of the patterns. Pouring temperature was observed as a process parameter alongside the mix ratios of the coating. Attempts were made to characterize the refractory coating by using two methods; differential thermal analysis (DTA) and X-ray diffraction. Attempt was also made to characterize the casting material. Gating system design was done for the plate casting to determine the correct proportions of the gating parameters in order to construct the gating system properly to avoid turbulence during pouring of liquid metal. A digital profilometer was used to take the measurements of the surface roughness. It was observed that the mix ratio 90% silica flour-10% kaolin produced the lowest value of the surface roughness of the plate castings and had the lowest material loss in the DTA test. The pouring temperature of 650o C produced best casting.
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Abstract

Based on real-time multi-domain communication signal analysis architecture, a high-efficiency blind carrier frequency estimation algorithm using the power spectrum symmetry of the measured modulated signal is presented. The proposed algorithm, which utilizes the moving averaged power spectrum achieved by the realtime spectrum analysis, iteratively identifies the carrier frequency in according to the power difference between the upper sideband and lower sideband, which is defined and revised by the estimated carrier frequency in each iteration. When the power difference of the two sidebands converges to the preset threshold, the carrier frequency can be obtained. For the modulation analysis, the measured signal can be coarsely compensated by the estimated result, and the residual carrier frequency error is eliminated by a following carrier synchronization loop. Compared with previous works, owing to the moving averaged power spectrum normalization and the smart iterative step variation mechanism for the two sidebands definition, the carrier frequency estimation accuracy and speed can be significantly improved without increasing the computational effort. Experimental results are included to demonstrate the outstanding performance of the proposed algorithm.
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Abstract

The aim of this study was to determine the solubility of CO2 in perfluorodecalin (PFD) which is frequently used as efficient liquid carrier of respiratory gases in bioprocess engineering. The application of perfluorinated liquid in a microsystem has been presented. Gas-liquid mass transfer during Taylor (slug) flow in a microchannel of circular cross section 0.4 mm in diameter has been investigated. A physicochemical system of the absorption of CO2 from the CO2/N2 mixture in perfluorodecalin has been applied. The Henry’s law constants have been found according to two theoretical approaches: physical (H = 1.22·10-3 mol/m3Pa) or chemical (H = 1.26·10-3 mol/m3Pa) absorption. We are hypothesising that the gas-liquid microchannel system is applicable to determine the solubility of respiratory gases in perfluorinated liquids.
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Abstract

The paper describes a bridge over the Vistula River with two spans of 180 English feet (54.86 metres) in length, constructed in the middle of the 17th century in the city of Torun on the territory of the Polish-Lithuanian Commonwealth. A study on numismatic and iconographic sources as well as city plans and written sources is carried out in the article. The study shows that the Torun Bridge superstructure was made of wood and was based on a cantilever truss (Gerber carrier) solution which had never been applied in Europe before. The two large spans of Torun Bridge were in service between 1632 and 1657. Accord- ing to the author’s research on well-known bridge structures from Europe from the middle of the 17th century, the span of the Torun bridge appears to have been the larger than the other.
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Abstract

A mathematical model of a hybrid culture system supported with a stationary layer of liquid perfluorochemical (PFC) as a source of O2 for cells which grow in the aqueous phase of culture medium has been developed and discussed. The two-substrate Monod kinetics without inhibition effects, i.e. the Tsao-Hanson equation, has been assumed to characterise the biomass growth. The Damköhler number which relates the growth rate to the mass transfer effects has been used to appraise the regime (i.e. diffusion-limited or kinetics) of the whole process. The proposed model predicted accurately previously published data on the submerged batch cultures of Nicotiana tabacum BY-2 heterotrophic cells performed in a culture system supported with a stationary layer of hydrophobic perfluorodecalin as a liquid O2 carrier. Estimated values of the parameters of the model showed that the process proceeded in the kinetics regime and the growth kinetics, not the effects of the mass transfer between aqueous phase and liquid PFC, had essential influence on the growth of biomass.
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Abstract

Fully synthetic, biochemically inert and water-immiscible liquid perfluorochemicals (PFCs) are recognised as flexible liquid carriers/scavengers of gaseous compounds (respiratory gases mainly, i.e. O2 and CO2) and increasingly applied in bioprocess engineering. A range of unmatched physicochemical properties of liquid PFCs, i.e. outstanding chemo- and thermostability, extremely low surface tension, simultaneous hydro- and lipophobicity, which result from carbon chain substitution with fluorine atoms (the most electronegative chemical element) and the presence of intramolecular C-F bonds (the strongest single bond known in organic chemistry) have been described in detail. Exceptional propensity to solubility of respiratory gases in liquid perfluorinated compounds has been widely discussed. Advantages and disadvantages of bioprocess applications of liquid PFCs in the form of a pure PFC as well as in an emulsified form have been pointed out. A liquid PFC-mediated mass transfer intensification in various types of microbial, plant cell and animal cell culture systems: from miniaturised microlitre-scale cultures, via biomaterial-based scaffolds containing culture systems, to litre-scale bioreactors, has been reviewed and elaborated on bearing in mind the benefits of bioprocesses.
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Abstract

In order to solve the problem of traditional carrier phase-shift modulation with multiple ratios or PI controllers and cumbersome tuning parameters, this paper uses improved carrier phase-shift modulation. The total turn-on number of sub-modules each bridge arm is determined by comparing the sinusoidal modulated wave with the triangular carrier, and then the control signal is generated according to the capacitance voltage sorting result and the bridge armcurrent polarity. However, this modulation method uses a sorting method that causes the insulated gate bipolar transistor (IGBT) have an excessively high switching frequency. Therefore, a sorting trigger condition that can effectively reduce the switching frequency is used. The method determines whether to reorder based on the error between the voltage average and the actual value. For the circulation problem, the double-frequency negative sequence component is extracted by rotating coordinate transformation, and it is suppressed by PI control. A 21-level MMC model was built in MATLAB/simulink to analyze the sub-module capacitor voltage fluctuation, output current, voltage distortion rate and bridge arm circulation. It is verified that the modulation method can combine the sorting algorithm and circulation suppression method at the same time, and has better voltage equalization and circulation suppression effects.
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