Прогнозирование и вероятностная оценка долговечности технических объектов

На основе методологии марковского анализа надежности предложен вероятностный подход к прогнозированию и оценке долговечности технических объектов. Разработана математическая модель прогнозирования долговечности с использованием статистических данных, характеризующих начальное и конечное распределение продолжительности срока службы технических объектов.На основі методології марківського аналізу надійності запропоновано ймовірнісний підхід до прогнозування та оцінки довговічності технічних об’єктів. Розроблено математичну модель прогнозування довговічності з використанням статистичних даних, що характеризують початковий та кінцевий розподіл тривалості терміну служби технічних об’єктів.Based on the methodology of the Markov analysis, a probabilistic approach to forecast and estimation of the longevity of technical objects is offered. A mathematical model of the longevity forecast is developed with the use of statistical data characterizing the initial and final distribution of the service term of technical objects

New data on the epidermal structure of the leaves of Podozamites Braun

In this paper, we study the morphological and epidermal features of leaves of Podozamites distans (type species) from two localities near that of the lectotype in Bavaria, Germany whose morphology is identical with the leaves of the lectotype, designated here. Emended diagnoses are provided for the genus Podozamites and its type species P. distans. Two new species, P. doludenkoae from the Kokala Formation (Toarcian, Early Jurassic) and the Karadiirmen' Formation (Bajocian, Middle Jurassic) of Mangyshlak (Kazakhstan), and P. irkutensis from the Prisayan Formation (Aalenian–Bajocian, Middle Jurassic) of Irkutsk Basin (East Siberia, Russia), are described. The species originally described as P. ex gr. lanceolatus from Southern Primorye, P. aff. eichwaldii and Podozamites sp. from the Bureya Basin have been attributed to P. doludenkoae. The species originally described as P. lanceolatus and P. lanceolatus var. longifolia (Prynada, 1962) from the Prisayan Formation of Irkutsk Basin has been proved to be identical with P. irkutensis

In situ pollen of voltzialean conifers from the Middle Triassic in Central Europe

Conifers of the order Voltziales were important components of Triassic floras. Their pollen is likewise abundant in microfloras from this period. Voltzialean pollen grains are known to have a considerable range of morphologies, but taxonomic distinctions based on these differences require thorough descriptions of in situ pollen from well-preserved male cones. We studied the pollen grains extracted from male cones from the palaeofloras of the Dont Formation in Italy, the Grès à Voltzia in France (both Anisian, lower Middle Triassic), and the Erfurt Formation in Germany (Ladinian, upper Middle Triassic). Pollen cones from the Dont Formation contain taeniate bisaccate pollen that are otherwise known only from Paleozoic conifers, as well as in one case multi-taeniate pollen grains resembling those commonly associated with seed ferns. By contrast, in situ pollen grains from the Grès à Voltzia and the Erfurt Formation are mostly comparable to Illinites, Angustisulcites or alete forms such as Voltziaceaesporites, Alisporites, and Klausipollenites. Malformations are usually rare, but notable are recurring patterns of smaller or larger than normal corpus sizes, which could lead to different taxonomic assignments if found dispersed. Overall, pollen grain sizes in general can vary considerably within a sample and even more between samples from different specimens of the same species. By contrast, size ranges of different species are overlapping significantly

Conifer Cone and Dwarf Shoot Diversity in the Anisian (Middle Triassic) of Kühwiesenkopf/Monte Prà della Vacca (Dolomites, Northeastern Italy)

Premise of research. The diversity of conifers from Kühwiesenkopf/Monte Prà della Vacca has been inferred previously on the basis of foliate branches/shoots and epidermal morphology. In this article we provide the description of the reproductive organs, which reveal a variety of forms, new morphologies and new taxa, and a comparison with other Permian–Triassic taxa, improving the knowledge of Triassic conifers. Methodology. The macromorphology, cuticles, and in situ pollen of the reproductive organs are described, and the macromorphological features are compared with those of other Permian–Triassic taxa. Pivotal results. The macro- and micromorphological analyses of the conifer reproductive organs of Kühwiesenkopf/Monte Prà della Vacca allow us to emend previously known taxa (i.e., Voltzia heterophylla, V. walchiaeformis, V. recubariensis, Pseudovoltzia edithae) and to describe new ones (i.e., cf. Voltzia sp. 1, Sidashia tridentata), providing in some cases almost complete whole-plant reconstructions. The macromorphological comparison of the Kühwiesenkopf/Monte Prà della Vacca taxa with other Permian–Triassic ones highlights the transitional character of some of them, especially P. edithae. The finding of amber anatomically connected to a V. walchiaeformis seed cone evidences the diversity of the botanical origins of the Anisian amber. Conclusions. The reproductive organs of the conifers of Kühwiesenkopf/Monte Prà della Vacca show in their morphology a mixture of characters typical of the early Permian to the Late Triassic Voltziales. Their study improves our knowledge of the reproductive biology of Anisian conifers and confirms the pivotal role of the “transitional” Triassic Voltziales that gave rise to modern groups of conifers

Sphenopterid diversity in the Kungurian of Tregiovo (Trento, NE-Italy)

The lower Permian fossiliferous deposit of Tregiovo, in the upper Val di Non (Trento Province, N-Italy), is known from the beginning of last century, since it has yielded invertebrate and vertebrate footprints, palynomorphs, conchostracans, and especially plant remains. In recent years, a new section in the Tregiovo Formation, called “Le Fraine”, located along the Lauregno provincial road, has been discovered. Two fossiliferous layers in this new section, one in the lower and one in the upper part of the section, yielded different plant assemblages. The radiometric dating of the volcanic formations under- and overlying the Tregiovo Formation, indicates a middle Kungurian age for the fossil-bearing sequence. More than 1000 specimens, impressions and compressions but without cuticles, have been found. The two plant assemblages are rich and diverse, and both are dominated by conifers (e.g., Feysia, Hermitia, Dolomitia) that range from 60 to 80% of the total assemblage, but also sphenophytes (Annularia), taeniopterids (Taeniopteris) and ginkgophytes (Sphenobaiera) occur. Most remarkable of these two assemblages is the high diversity of sphenopterids that are sometimes preserved as complete fronds. At least five different species can be attributed to the genus Sphenopteris, i.e. Sphenopteris kukukiana, Sphenopteris suessii, Sphenopteris. sp. cf. S. geinitzii, Sphenopteris sp. and a morphotype that represents a new species, Sphenopteris valentinii. The leaves of most Sphenopteris species look pretty stiff and have strongly dissected pinnules with very narrow, linear rigid segments, apparently being an adaptation to arid conditions. The Tregiovo flora is of great importance, not only because of its richness and diversity, especially with regard to sphenopterids, but also because it is one of the very few well-dated Kungurian floras from Euramerica

Variability of in situ spores in some leptosporangiate ferns from the Triassic in Italy and Austria

Spores or pollen from a single species or even an individual plant or sporangium may vary in morphology and size to a point that equivalent forms found dispersed in the sediment have been described as different species or even genera. In addition, not all these organs were mature at the moment of burial, and therefore they do not always contain completely developed microspores. To understand these variations better, we studied the intraspecific and interspecific morphological variability of in situ spores of leptosporangiate ferns (belonging to the Osmundales, possible Osmundales, and Gleicheniales) from the Triassic of Europe. The material comes from the Anisian Kühwiesenkopf/Monte Prà della Vacca flora of Italy and the Carnian Lunz flora of Austria. Our analysis is aimed at distinguishing the normal range of variability, differentiating developmental stages, and determining the frequency of abnormal spores. Results show significant variation in both size and surface ornamentation of spores from the same sporangia, as well as between sporangia and individuals, which may have various causes. Abortive spores are usually rare but occur with higher frequency in different samples from some specimens, suggesting that they can serve to identify systemic defects in the plants

Differentiation of the fossil leaves assigned to Taeniopteris, Nilssoniopteris and Nilssonia with a comparison to similar genera

Taeniopterid leaves are characterized by an entire margin and a midrib with secondary veins that may or may not bifurcate. This artificial group contains leaves that belong to ferns or, mainly cycadophyte, gymnosperms. If cuticle or reproductive structures are present, the leaves can be placed in natural groups and genera, such as Nilssonia and Nilssoniopteris. If not, they are placed in the fossil-genus Taeniopteris. However, nomenclatorial issues around these genera were complicated and most have only recently been solved. Here we briefly describe and differentiate between these three genera, including diagnoses and type species, all of which are figured. Other, similar but less well known or not often used genera are briefly discussed as well. Moreover we provide taxonomic keys to help determine the generic affiliation of such fossils