Grzegorz P. Łysiak, Robert Kurlus and Anna Michalska
The aim of this research was the evaluation of whether the application of 5-ALA, which has potential as a plant growth stimulating agent with indirect anti-stress activity, can limit the damage caused by low temperatures in winter. The research was conducted on frost-sensitive apple cultivars for three years in an orchard and in a laboratory. During the vegetative seasons of each year, the trees of three apple cultivars (‘Golden Delicious’, ‘Gala’ and ‘Šampion’) were subject to 5-ALA foliar application. Three times during each winter following the field application, apple shoots were taken to the laboratory and frozen at −20°C, −25°C and −30°C. After incubation, the damage to the sensitive parts of the shoots was evaluated. The application had a positive effect on the frost resistance of all cultivars, most often at the end of dormancy, which is especially noteworthy because frost damage occurs most frequently during this period. Positive effects of the application were found in most of the experiment combinations of cultivar, year, freezing date and shoot part. Additionally, the positive influence of 5-ALA application on frost resistance was found to increase with each year of the research.
M. Bukowski, P. Łysiak, R. Oleszek and W. Trochymiak
Development of the transport infrastructure in Poland has contributed to the implementation of various technologies of construction of bridges and their components. Use of reinforced soil for construction of embankments, retaining structures (RSS walls) and abutments is one of the solutions which has been frequently used for the past twenty years. Shortly after its development, the technology proposed by Henri Vidal in 1966 also gained appreciation in Poland . Reinforced soil bridge abutments started to be widely used in Poland at the turn of the 20th century. The bridge facilities at the junction of Trasa Siekierkowska route and Wał Miedzeszyński Street in Warsaw, which were built in the years 2000÷2002, are an example of structures from that period. The authors of this paper have been particularly interested in the outermost supports of the reinforced concrete flyovers which were constructed in the form of intermediate reinforced soil abutments. Offsets – the vertical displacements, in the range of 15÷25mm, emerging between the level of the road surface and the steel elements of the expansion joints which separate the flyover’s structure from the embankment – were observed in 2015, in the course of regular inspections. While accounting for the observations which have been made, the surveying measurements and the ground investigation, the paper diagnoses and describes the mechanism which led to the emergence of the offsets. Potential patterns of the occurrence of additional settlements, as the reason for emergence of the offsets, were identified and analyzed. The settlement of the outermost support (abutment), as a result of increase of relative density of alluvial sands due to the dynamic interaction of the roadways of Wał Miedzeszyński Street, was analyzed. Analytical and numeric approaches were used in the course of analysis while relying on PLAXIS and MIDAS software.