In this paper a cross-shaped isolator consisting of cuboidal magnets and a cylindrical isolator are compared by resonance frequency to volume ratio and shape. Both isolators are capable of obtaining a low resonance frequency, i.e. 0.15 Hz and 0.01 Hz for the cross and cylinder, respectively. The volume of both isolators is comparable, only the shape is different, resulting in a tall structure with a small footprint for the cross and a flat with a large diameter cylindrical structure. A sensitivity analysis shows that due to the large amount of magnets, the cross-shaped isolator is less sensitive to manufacturing tolerances.
First psychological research at Arctowski station were conducted in 1979. In the nineties the American team under direction of prof. L. Palinkas conducted research in order to determine the patterns of multicultural psychosocial adaptation. The author discusses stress as a result of isolation and extreme conditions.
The article presents the research on the reduction of noise and vibrations carried out using screen theory and its implementation in practice. Acoustic screens are divided according to their application and structures. The article deals with the application of screens in practice, gives their theoretical evaluation and analyses influences of their structure and materials. The evaluation of positive and negative acoustic properties of the screens is given. The conclusion is that screen acoustic properties may be improved by including new elements into design of screens, thus increasing their efficiency in reducing noise effect. Theoretical calculations are performed, and the obtained results are analyzed. In conclusion, it is stated that cylindrical, semi-cylindrical or conical elements have to be applied in the screens.
In this fast-changing environmental condition, the effect of fossil fuel in vehicle is a significant concern. Many sustainable sources are being studied to replace the exhausting fossil fuel in most of the countries. This paper surveys the types of electric vehicle’s energy sources and current scenario of the onroad electric vehicle and its technical challenges. It summarizes the number of state-of-the-art research progresses in bidirectional dcdc converters and its control strategies reported in last two decades. The performance of the various topologies of bidirectional dc-dc converters is also tabulated along with their references. Hence, this work will present a clear view on the development of state-of-the-art topologies in bidirectional dc-dc converters. This review paper will be a guide for the researchers for selecting suitable bidirectional traction dc-dc converters for electric vehicle and it gives the clear picture of this research field.
The technical requirements for the determination of physical parameters of vibration isolating material have not been standardized in Europe and Poland yet, which significantly hinders the ability to compare vibration isolating materials offered on the market. Therefore, there is a need for establishing a norm that could be applied both for the determination of the physico-mechanical properties of elastic vibration isolation elements in rail transport for domestic and foreign producers as well as in their selection for application in a specific vibration isolation system. The paper presents a proposal to standardize the methodology of the estimation of vibration isolation materials physical parameters authorized for use in vibration isolation systems used in rail transport. Methodology for measuring the physico-mechanical parameters of vibration isolating material presented in the paper forms uniform test procedure developed based on a fragmentary norms for flexible materials testing. The use of the proposed research methodology enables the creation of a unified database of elastic materials which parameters will be easy to compare, and choice between them will become easier for designers of vibration isolation systems used in rail transport.
Phytophthora cambivora was isolated from the bark lesions of two 10- and 15-year-old of analysed alder trees. Additionally, Botrytis cinerea, 3 Fusarium species, Mucor spp., P. alni and Trichoderma spp. were recovered from diseased tissues. Isolates of P. cambivora from six plant species, used for inoculation of alder seedlings and plant parts, cause dthe development of necrosis. Isolate from Chamaecyparis lawsoniana was the weakest pathogen whereas those from Abies alba, Acer pennsylvanicum and Alnus glutinosa were the strongest.
Phytophthora citricola was isolated from diseased seedlings of European beech and Silver fir taken from the most of surveyed nurseries. Fusarium species, Pythium ultimum and Rhizoctonia solani were also found in diseased plant tissues.Isoates of P. citricola fro mboth plants and additionally from heather and rhododendron colonised leaf blades, needles and stem parts of beech and fir. In greenhouse trials on inoculated 1-year-old seedlings necrosis spread about 2 mm/24 hr on beech stems whereas on fir about 1.5 mm/24 hr.
Research over a three year period indicated that P. ramorum occurred rarely in Poland on Rhododendron spp., in spite of established monitoring in nurseries, trade stands, forest and water from early spring to late autumn each year. The pathogen was not found in forests on Vaccinium vitisidaea, Calluna vulgaris, Fagus sylvatica and Quercus rubra, proving its limited spread. The species was detected, however, from 2 rivers. P. citricola was isolated from most of surveyed plants. Besides this P. cactorum, P. cinnamomi, P.citrophthora and P. nicotianae var. nicotianae were isolated from diseased plants. Additionally Pestalotia sydowiana, species of Fusarium, Botrytis cinerea and Trichoderma were often found in diseased plant tissues. Laboratory and glasshouse research showed slight differences in colonization of plants by P. ramorum and P. citricola. However, taking into account the range of host plants, and frequency of pathogen occurrence in infected plant material and water, it became clear that P. citricola poses a much greater danger than P. ramorum to the natural environment in Poland.
The paper presents an analogue circuit testing method that engages the analysis of the time response to a non-periodic stimulus specialized for the verification of selected specifications. The decision about the current circuit diagnostic state depends on an amplitude spectrum decomposition of the time response measured during the test. A shape of the test excitation spectrum is optimized with the use of a differential evolution algorithm and it allows for achieving maximum fault coverage and the optimal conditions for fault isolation. Genotypes of the evolutionary system encode the amplitude spectrum of candidates for testing stimuli by means of rectangle frequency windows with amplitudes determined evolutionarily.
Stem canker and black scurf of potato (Solanum tuberosum L.) caused by Rhizoctonia solani Kühn are important and epidemic diseases in potato-growing regions worldwide, including Iran. In this study, 120 isolates were retrieved from infected stem canker from six potato- growing regions in Iran (Isfahan, Ardebil, Fars, Hamedan, Kurdestan and Kerman). Out of these, 30 isolates were selected as representatives for genetic and virulence analysis. The isolates were analyzed by one sequence analyzes of the ITS-rDNA region, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies. Based on sequence analysis of the ITS-rDNA region, all 30 isolates were assigned to the anastomosis group (AG) and all were assigned to AG-3 PT. Cluster analysis using the unweighted pair group method with the arithmetic averages (UPGMA) method for both RAPD and ISSR markers revealed that they were divided into three main groups, with no correlation to geographical regions of the isolates. Pathogenicity tests showed that all isolates were pathogenic on potato cv. Agria; however, virulence variability was observed among the isolates. The grouping based on RAPD analysis and virulence variability was not correlated.
RNA extraction involves several main stages, regardless of the method of extraction: homogenization, effective denaturation of proteins from RNA, inactivation of ribonuclease and removal of any DNA, protein, and some residual contamination. Isolation of undamaged intact RNA is challenging when the related tissue contains high levels of polysaccharides and phenols. Several efforts have been made towards the comparison and optimization of extraction and purification methods for RNA from plant tissues. This is dictated by the necessity of obtaining RNA of a good quality and in a sufficient quantity for further molecular analyzes. Plant storage organs (such as bulbs or seeds) rich in polysaccharide and polyphenolic compounds present distinct challenges for total RNA isolation. Such components, considered in this case as contamination, may bind and co-precipitate with nucleic acids and negatively affect later assays. Since standard routine protocols yield unacceptable results in bulbs, we have designed a new method for RNA extraction. We used two modified procedures (based on CTAB and sarkosyl reagents) of RNA extraction from so called “difficult plant material” and compared them to a popular RNA isolation base on the column isolation kit and TriPure reagent. Our modified protocols dealt with problems of both RNA degradation and low yield caused by co-purification with polysaccharides present in plant bulbs. In this study we have shown that improvement of the CTAB and sarkosyl method with a lyophilization step of plant tissues leads to isolation of high quality RNA from difficult material like storage organs of bulbous plants. The main changes in the procedure compared to the previously described methods concerned the different order of lithium chloride and sodium acetate addition, lithium chloride concentration increase and modification of centrifugation conditions. Gel electrophoresis and spectrophotometer analysis confirmed the high quality and integrity of the obtained RNA. The modified procedures allowed for obtaining a satisfying amount of RNA concentration in the range from 280 to 950 ng/μl depending on the plant species. Thus, the demonstrated RNA isolation methods are efficient and can be used for plant material rich in polysaccharides, such as bulbs.