A novel approach for construction of radiocarbon-based chronologies for speleothems

Robust chronologies are crucial for the correct interpretation of climate proxy records and for detailed reconstructions of palaeoclimate. Stalagmites have garnered strong interest as recorders of past climate in part due to their amenability to U-series dating. However, many stalagmites are not dateable using this technique due to low 238U and/or high detrital Th concentrations (e.g., many tropical cave systems (Adkins et al., 2013)), and occasionally these issues affect stalagmites across wide geographical regions (e.g., large parts of Australia (Green et al. 2013)) complicating the use of stalagmites in these areas. Radiocarbon (14C) offers an alternative method of dating stalagmites, but issues associated with the ‘dead carbon fraction’ (DCF) have historically hindered this approach. Here, a novel 14C-based method for dating stalagmites is presented and discussed. The technique calculates a best-fit growth rate between a time-series of stalagmite 14C data and known atmospheric 14C variability. The new method produces excellent results for stalagmites that satisfy four requirements: i) the absence of long-term secular variability in DCF (i.e., stalagmite DCF varies around a mean value with no long-term trend), ii) stalagmite growth rate does not vary significantly (the technique identifies stalagmites with substantial growth rate variability), iii) the stalagmite record is long enough that measurable 14C decay has occurred, and iv) one ‘anchor’ point exists where the calendar age is known. The model produces good results for a previously U–Th dated stalagmite from Heshang Cave, China, and is then applied to an undated stalagmite from southern Poland. The new method will not replace high-precision U–Th measurements, because the precision of the technique is difficult to quantify. However, it provides a means for dating certain stalagmites undateable by conventional U–Th methods and for refining coarse U–Th chronologies

Wpływ stanu utrzymania terenów zalewowych Wisły na poziomy wysokich wód na odcinku od Włocławka do Torunia

This article describes the methodology of hydraulic calculations to estimate the water levels in open channels for steady gradually varied flow. The presented method has been used to analyse the water level on the Vistula River from Włocławek cross-section to Toruń cross-section. The HEC-RAS modelling system has been used for parameterization of the river channel and flood¬plains, as well as for flow simulation. The results obtained have been the basis for assessing the impact of maintenance of floodplains on water level during maximum discharges.W artykule opisano metodykę obliczeń hydraulicznych umożliwiających wyznaczenie układu zwierciadła wody w korytach otwartych w warunkach wolnozmiennego przepływu ustalonego. Wybraną metodę wykorzystano do analizy układu zwierciadła wody w rzece Wiśle na odcinku od przekroju Włocławek do przekroju Toruń. Do parametryzacji koryta i terenów zalewowych rzeki, jak również do symulacji przepływu, wykorzystano program obliczeniowy HEC-RAS. Na podstawie uzyskanych wyników oceniono wpływ stanu utrzymania terenów zalewowych na położenie zwierciadła w trakcie występowania przepływów maksymalnych

Swimming ponds: close to nature

Water in a swimming pond is purified through natural processes of self-cleaning so there is no need to use chemicals necessary to maintain traditional swimming pools. It is safe for humans and the environment, combining the benefits of a swimming pool and a garden pond. It may be used in private gardens and public recreational facilities. Its construction and maintenance is usually much cheaper and it blends harmoniously into the natural landscape. In this context, the authors discuss the basics of construction and maintenance of swimming ponds, selection of water plants, and relevant legal aspects

A mobility analysis of using the Rhex-type mobile robot in various surroundings

Mobile robots are becoming increasingly popular, finding a great deal of applications, especially in situations where conventional mobility systems, such as wheels or tracks, prove ineffective. Exploration of an unknown environment or a place, in which Man is incapable of staying, for example exploring remote planets in the Solar System, is often linked with operating a device in a rough terrain. This requires an adjustment of the robot locomotion system to the ground. The problem of high mobility in diverse surroundings is still a major challenge. Therefore, the concept of mobile robots is extremely popular and is still being developed. Using this type of propulsion carries several advantages, namely the possibility of applicability of this type of solutions in an environment, which is not easily accessible to wheeled vehicles (sandy, mountainous terrain, etc.). There is still a large interest of constructors and scientists in unconventional drive systems, adapted directly from nature, which often offers very efficient solutions. Quite frequently, designers copy the construction of animal locomotion system, attempting at implementing them in their designs. The aim of this article is to present an original construction, known as the Rhex-type robot in the available literature. In addition, it presents a number of conducted investigations, which describe the platform’s mobility in various terrains, such as sands, rocks and rubbles, as well as the possibility to overcome the terrain obstacles. It ends with conclusions and potential application areas of this type of a design

Potencjał hydroenergetyczny dolnej Wisły

This paper presents an estimate analysis of the hydropower potential of the lower Vistula River from Warsaw to Gdańsk Bay. The calculations were made for a hydraulic model of the lower Vistula which takes into account potential development of barrages in a cascade system. Results obtained from the model simulations and from hydrological calculations were used to estimate the power of hydropower plants and the average annual energy output from the entire cascade system. The results of calculations indicate significant energy benefits resulting from the development of a cascade of hydropower plants in the lower Vistula. This study does not discuss the cascade project’s economic viability or other aspects of its development (inland waterways, flood control, etc.).W artykule przedstawiono szacunkową analizę potencjału hydroenergetycznego dolnej Wisły na odcinku od Warszawy do Zatoki Gdańskiej. Obliczenia wykonano, przyjmując model hydrauliczny dolnej Wisły, w którym uwzględniono potencjalną zabudowę stopniami wodnymi pracującymi w układzie kaskady zwartej. Uzyskane wyniki symulacji z modelu wraz z przeprowadzonymi obliczeniami hydrologicznymi posłużyły do oszacowania mocy elektrowni wodnych oraz średniej rocznej produkcji energii całego układu kaskady. Otrzymane wyniki obliczeń wskazują na znaczące korzyści energetyczne wynikające z budowy kaskady elektrowni wodnych na dolnej Wiśle. W pracy nie podjęto ekonomicznej kwestii opłacalności wykonania analizowanej kaskady, jak również innych aspektów istnienia kaskady (żegluga śródlądowa, ochrona przeciwpowodziowa i inne)

Luminescent Macrocyclic Lanthanide Complexes Bearing N-Oxides: Potential Fluorescent Labels for Modern Medical Diagnostics

Macrocyclic and macropolycyclic ligands incorporating heteroaromatic N-oxides (3,3'-biisoquinoline-2,2'-dioxide) form strongly luminescent complexes with lanthanide ions: Eu(III) and Tb(III). Most of these complexes are stable water solutions, with excellent luminescent properties, regarding luminescence lifetimes in the range of 0.2-0.7 ms, and the quantum yields for emission up to 0.25. Several complexes are stable also in the presence of affecting ions, such as Ca(II), or phosphates. These features make them attractive as potential fluorescent labels for time-resolved fluoroimmunoassays