An attempt to reduce the vibration of gearbox with non-parallel shaft axes by modifying the spur gear fixing method

In this paper authors carried out research, while modified gear fixing was used to limit the vibrations of the gearbox with non-parallel shaft axes. For tests modified back-to-back test stand was used. During test gearbox worked without load, with various rotational frequency and value of non-parallelism of shafts axes. Analysis of the obtained results presents that only in some cases the use of modified fixing of gear causes a reduction of the measured vibrations

Dependence of damage to the running surface of the railway rail on the vibroacoustic signal of a passing passenger train

The article presents an extended summary regarding the impact of rail damage on vibration waveforms and vibroacoustic spectrum images of vibrations. The analyzed example is based on the passage of the train depot – passenger train on a selected railway line. A short summary of the analyzed research problem is also presented

Assessment of serpulid-hydroid association through the Jurassic : a case study from the Polish Basin

The coexistence of sessile, tube-dwelling polychaetes (serpulids) and hydroids, has been investigated. Serpulid tubes bearing traces after hydroids are derived from different stratigraphic intervals spanning the Middle and Upper Jurassic, the rocks of which represent the diverse paleoenvironments of the Polish Basin. Although fossil colonial hydroids classified under the species Protulophila gestroi are a commonly occurring symbiont of these polychaetes during the Late Cretaceous and Cenozoic, they seem to be significantly less frequent during the Jurassic and limited to specific paleoenvironments. The hydroids described here are represented by traces after a thin stolonal network with elongated polyp chambers that open to the outer polychaete tube’s surface with small, more or less subcircular apertures. Small chimney-like bulges around openings are an effect of the incorporation of the organism by in vivo embedment (bioclaustration) within the outer layers of the calcareous tube of the serpulid host. Considering the rich collection of well-preserved serpulid tubes (>3000 specimens), the frequency of bioclaustrated hydroids is very low, with an infestation percentage of only 0.6% (20 cases). It has been noticed that only specimens of the genus Propomatoceros from the Upper Bajocian, Lower Bathonian, Middle Bathonian, and Callovian have been found infested. However, the majority of bioclaustrated hydroids (17 cases) have been recorded in the Middle Bathonian serpulid species Propomatoceros lumbricalis coming from a single sampled site. Representatives of other genera are not affected, which is congruent with previous reports indicating that Protulophila gestroi was strongly selective in the choice of its host. A presumably commensal relationship is compared with the recent symbiosis between the hydroids of the genus Proboscidactyla and certain genera of sabellid polychaetes

Neodymium isotopes in peat reveal past local environmental disturbances

Funding The Stawek profile radiocarbon dating and investigation and neodymium measurements were financed by the National Science Centre, Poland, grants no. 2019/03/X/ST10/00849 and 2020/39/D/ST10/00641. The Głęboczek profile radiocarbon dating and investigation were financed by the National Science Centre, Poland, grant no. 2015/17/B/ST10/01656.Peer reviewedPublisher PD

Fires, vegetation, and human - The history of critical transitions during the last 1000 years in Northeastern Mongolia

Fires are natural phenomena that impact human behaviors, vegetation, and landscape functions. However, the long-term history of fire, especially in the permafrost marginal zone of Central Asia (Mongolia), is poorly understood. This paper presents the results of radiocarbon and short-lived radionuclides (210Pb and 137Cs) dating, pollen, geochemical, charcoal, and statistical analyses (Kohonen's artificial neural network) of sediment core obtained from Northern Mongolia (the Khentii Mountains region). Therefore, we present the first high-resolution fire history from Northern Mongolia covering the last 1000 years, based on a multiproxy analysis of peat archive data. The results revealed that most of the fires in the region were likely initiated by natural factors, which were probably related to heatwaves causing prolonged droughts. We have demonstrated the link between enhanced fires and “dzud”, a local climatic phenomenon. The number of livestock, which has been increasing for several decades, and the observed climatic changes are superimposed to cause “dzud”, a deadly combination of droughts and snowy winter, which affects fire intensity. We observed that the study area has a sensitive ecosystem that reacts quickly to climate change. In terms of changes in the vegetation, the reconstruction reflected climate variations during the last millennium, the degradation of permafrost and occurrence of fires. However, more sites with good chronologies are needed to thoroughly understand the spatial relationships between changing climate, permafrost degradation, and vegetation change, which ultimately affect the nomadic societies in the region of Central and Northern Mongolia.National Science Centre, Poland (Grant no.: 2017/01/X/ST10/01216 and 2018/31/B/ST10/02498); Polish-Mongolian Joint Research Project – “Environmental changes in the Northern Mongolia under recent and past climate variability”. Russian Science Foundation (Grant No. 20-17-00110

Hydrological dynamics and fire history of the last 1300years in western Siberia reconstructed from a high-resolution, ombrotrophic peat archive

International audienceSiberian peatlands provide records of past changes in the continental climate of Eurasia. We analyzed a core from Mukhrino mire in western Siberia to reconstruct environmental change in this region over the last 1300 years. The pollen analysis revealed little variation of local pine-birch forests. A testate amoebae transfer function was used to generate a quantitative water-table reconstruction; pollen, plant macrofossils, and charcoal were analyzed to reconstruct changes in vegetation and fire activity. The study revealed that Mukhrino mire was wet until the Little Ice Age (LIA), when drought was recorded. Dry conditions during the LIA are consistent with other studies from central and eastern Europe, and with the pattern of carbon accumulation across the Northern Hemisphere. A significant increase in fire activity between ca. AD 1975 and 1990 may be associated with the development of the nearby city of Khanty-Mansiysk, as well as with the prevailing positive Arctic Oscillation

Risk factors for reoperation after surgical treatment for degenerative spinal disease in Poland: a nationwide retrospective study of 38,953 hospitalisations

Introduction. Degenerative spinal disease (DSD) is one of the most common musculoskeletal conditions and a leading cause of sickness absence. It also contributes significantly to the global burden of disease. The aim of this study was to assess the frequency of reoperation after surgical treatment of DSDs in Poland, and to identify risk factors for reoperation.Material and methods. A retrospective analysis of hospitalisations for DSD in 2018 that were reported to Poland’s National Health Fund (NHF) was performed. Reoperations reported within 365 days of hospital discharge were identified. Demographic factors and multimorbidities were included in the analysis. A logistic regression model was then performed to assess risk factors for reoperations.Results. In 2018, 38,953 surgical hospitalszations for DSD were reported. A total of 3,942 hospitalised patients (10.12%) required reoperation within 365 days. Patients requiring reoperation were predominantly female (female-to-male ratio 1.34:1) and elderly (mean age of reoperated patients 56.66 years, mean age of other patients 53.24). The percentage reoperated upon correlated with multiple diseases (from 8.81% in the group of patients without comorbidities to 15.31% in the group of patients with three or more comorbidities). The risk of reoperation was most increased by comorbid depression, neurological diseases, obesity, and older age. The risk of reoperation was reduced by instrumented spinal surgery, surgery in a neurosurgical unit, and hospitalisations other than same-day surgery.Conclusions. Reoperations within a year after DSD surgical treatment are common. Identifying risk factors for reoperation, including those related to the presence of comorbidities and the phenomenon of multimorbidity, can be an important tool in reducing reoperation rates

Effects of experimental warming on Betula nana epidermal cell growth tested over its maximum climatological growth range

Numerous long-term, free-air plant growth facilities currently explore vegetation responses to the ongoing climate change in northern latitudes. Open top chamber (OTC) experiments as well as the experimental set-ups with active warming focus on many facets of plant growth and performance, but information on morphological alterations of plant cells is still scarce. Here we compare the effects of in-situ warming on leaf epidermal cell expansion in dwarf birch, Betula nana in Finland, Greenland, and Poland. The localities of the three in-situ warming experiments represent contrasting regions of B. nana distribution, with the sites in Finland and Greenland representing the current main distribution in low and high Arctic, respectively, and the continental site in Poland as a B. nana relict Holocene microrefugium. We quantified the epidermal cell lateral expansion by microscopic analysis of B. nana leaf cuticles. The leaves were produced in paired experimental treatment plots with either artificial warming or ambient temperature. At all localities, the leaves were collected in two years at the end of the growing season to facilitate between-site and within-site comparison. The measured parameters included the epidermal cell area and circumference, and using these, the degree of cell wall undulation was calculated as an Undulation Index (UI). We found enhanced leaf epidermal cell expansion under experimental warming, except for the extremely low temperature Greenland site where no significant difference occurred between the treatments. These results demonstrate a strong response of leaf growth at individual cell level to growing season temperature, but also suggest that in harsh conditions other environmental factors may limit this response. Our results provide evidence of the relevance of climate warming for plant leaf maturation and underpin the importance of studies covering large geographical scales.Peer reviewe

Human-induced fire regime shifts during 19th century industrialization: A robust fire regime reconstruction using northern Polish lake sediments

Fire regime shifts are driven by climate and natural vegetation changes, but can be strongly affected by human land management. Yet, it is poorly known how humans have influenced fire regimes prior to active wildfire suppression. Among the last 250 years, the human contribution to the global increase in fire occurrence during the mid-19th century is especially unclear, as data sources are limited. Here, we test the extent to which forest management has driven fire regime shifts in a temperate forest landscape. We combine multiple fire proxies (macroscopic charcoal and fire-related biomarkers) derived from highly resolved lake sediments (i.e., 3–5 years per sample), and apply a new statistical approach to classify source area- and temperature-specific fire regimes (biomass burnt, fire episodes). We compare these records with independent climate and vegetation reconstructions. We find two prominent fire regime shifts during the 19th and 20th centuries, driven by an adaptive socio-ecological cycle in human forest management. Although individual fire episodes were triggered mainly by arson (as described in historical documents) during dry summers, the biomass burnt increased unintentionally during the mid-19th century due to the plantation of flammable, fast-growing pine tree monocultures needed for industrialization. State forest management reacted with active fire management and suppression during the 20th century. However, pine cover has been increasing since the 1990s and climate projections predict increasingly dry conditions, suggesting a renewed need for adaptations to reduce the increasing fire risk. © 2019 Dietze et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Znaczenie wysokorozdzielczych wielowskaźnikowych (multi-proxy) badań paleoekologicznych dla geografii historycznej i historii gospodarczej

The article presents the importance of palaeoecology for the study of economic history, historical geography and environmental history. The text introduces the methodological possibilities of palaeoecology. We pay attention to the unused potential of high resolution palaeoecology. By using natural archives (sediments of lakes and peatlands), we are able to trace the history of changes in nature. We can reconstruct history and better understand the changes in Poland’s ecosystems and its economic development.Artykuł prezentuje znaczenie paleoekologii dla badań historii gospodarczej, geografii historycznej i historii środowiskowej. Praca przybliża możliwości metodyczne paleoekologii. Zwracamy uwagę na niewykorzystany dotąd potencjał wysokorozdzielczej paleoekologii. Wykorzystując naturalne archiwa (osady jezior i torfowisk), jesteśmy w stanie prześledzić historię przemian przyrody, możemy zrekonstruować historię i lepiej zrozumieć zmiany ekosystemów Polski oraz jej rozwój ekonomiczny