Yield criteria for glaciotectonically deformed deposits

Most glaciotectonically deformed deposits, including varved clays and glacial tills, are characterised by cracks and fissures. This paper presents a method for describing the yield criteria for glacitectonically deformed cohesive deposits using a model of cracked geomaterial with isotropic or anisotropic matrix. The general representation of the limit conditions for anisotropic materials in plane-strain is used to determine the yield criterion. The yield criterion represents a convex, piece-wise surface in the three-dimensional stress space revealing explicitly global, plastic properties of the materials considered. An example of using proposed yield criteria to solve a bearing capacity problem of a strip foundation constructed on a glaciotectonically cracked layer is presented. The lower and upper-bound estimates of limit loads on the strip footing are given. The limit state analysis presented in this paper can be used to solve many other geotechnical engineering problems, for example, the stability of slopes and reinforced walls or the bearing capacity of pile foundations

Subvolcanic rocks of the Żeleźniak intrusion (Kaczawa Mountains) compared with the Karkonosze granite

The Żeleźniak intrusion (Kaczawa Mts.) has been usually correlated with the Karkonosze pluton, and a common igneous source of these two bodies was suggested. This paper presents the results of geochemical investigation (main, trace and rare elements) for Żeleźniak igneous rocks and hypothetically related Karkonosze granite (from the Janowice Wielkie area). The preliminary data correlation shows that their co-magmatic origin is rather unlikely

The Baga-Gazriin Chuluu A-type granites of Central Mongolia compared with other igneous bodies nearby : a geochemical approach

The subject of the study are the relationships between the Late Triassic A-type granites of the Baga-Gazriin Chuluu pluton in Central Mongolia and the magmatic bodies located either adjacent to or a short distance from this intrusion. We compare new geochemical data from the most representative samples of the Baga-Gazriin Chuluu pluton with published data from the Mesozoic granitoids of the Egiindavaa complex and T sagduul massif in the Hotont area. The geochemical analyses of all these granitoids are also compared with the geochemical characteristics of trachyandesites of unknown age which neighbour the Baga-Gazriin pluton. The Baga-Gazriin granites, most of the Tsagduul granites and a few samples from Egiindavaa are A-granites with strong crustal affinity. By contrast, most of the Egiindavaa granitoids include considerable mantle-derived material and thus seemingly formed in different conditions, with a higher water content in the magma. The trachyandesites adjacent to the Baga-Gazriin Chuluu pluton have been referred to a Permian volcano-sedimentary complex, making them distinctly older than the granitoids. All the A-type granites discussed were emplaced in extensional conditions, which developed after cessation of the compressional regime resulting from the closure of the Mongol-Okhotsk Ocean. The shallow-lying source for their generation was connected with slab break-off or the presence of a hot spot. The granitoids, in the late stage of crystallisation, were enriched in complex ions that were REE carriers, as shown by a distinct “tetrad effect”

Determination of liquidity index of glacial tills based on the fall cone single point methods

Liquidity index (IL) is one of the basic geotechnical parameters of cohesive soils. It defines the consistency and physical state of soil. Since the state of the cohesive soil determines the bearing capacity of the subsoil, the value of IL is often used for various correlations used in the design of foundations. The cone penetrometer is a device used to determine the liquid limit (wL) based on which the value of the liquidity index is calculated according to both Polish (PN-88/B-04481) and European (PKN-CEN ISO/TS 17892-12) standards. In this method the liquid limit is read out from the relationship between the moisture content of soil paste and the depth of cone penetration. This relationship must be determined by interpolation between at least four test points. However, several, so-called single point methods, can be found in the literature. They are to be used for a quick and efficient measurement of the liquid limit using existing empirical correlations. This article discusses the possibility of applying some of those methods to calculate the value of the liquidity index for selected cohesive soils. The analysis was carried out on ablation and subglacial tills which occur in northern and north-western Poland. Based on the test results it is concluded that the empirical formulae used in the single point methods have a limited application and should be used with caution taking into account the type, genesis and mineral composition of examined deposit

Współpraca i ryzyko współpracy w małych i średnich przedsiębiorstwach technologicznych

Background: Despite their relatively low economic potential and modest scale of activity of each single unit, en masse small and medium size enterprises (SMEs) create a major part of real GDP in all developed countries. Moreover, having very rarely own R&D backup facilities, SMEs are mostly strikingly open for new technical and technological solutions, perceiving innovations as a challenge and as an opportunity as well. Searching for such solutions, also in processes of implementation, they have to collaborate with a number of partners from various sectors, having diverse legal status, business culture and approach to cooperation. Frequently collaboration appears to be a source of problems, even threats. Methods: The paper consists of a literature review, identification of collaboration risk areas and - as a separate part - presentation and discussion of selected results of own research conducted late 2016 by the authors within a group of over 300 small and medium technological enterprises (SMTEs), chosen according to the defined filters. The aim of research was to analyse the collaboration environment of SMTEs, their approach to collaboration and perception of collaboration problems and risks. Results: Analysis of uncertainty areas within SMTEs' environment and modes of operation allowed to identify a selection of risks which may result from collaboration, divided into two divisions: those having general character, which may be observed in each SME, and those being SMTE specific, adjoint to acquiring of new technologies, cooperation with scientific R&D institutions, technology transfer etc. The survey - considering the strong specific features of SMTEs - delivered some interesting informations on characteristics of sources of new technologies, collaboration directions and relations with partners, also collaboration risk factors and exposure. Conclusions: The paper shows a variety of problems referring to SMTEs' collaboration with partners in technology acquisition and implementation. Having difficulties in contacts with big enterprises and institutions, they prefer own solutions and cooperation with other SMEs. This obviously imposes some limitations on the choice of partners and availability of solutions, making relations more complex and difficult. From the survey results also that SMTEs do not regard vulnerability and exposure on collaboration risk as a major problem in their activities, however some risk factors - from legal ones to soft competencies of partners. Further research could refer to the low effectiveness of collaboration between SMTEs and institutions which are regarded as a natural source of innovative solutions and those which exist to support that sector.Wstęp: Pomimo relatywnie niskiego potencjału ekonomicznego i umiarkowanej skali działalności każdej pojedynczej firmy, w swojej masie małe i średnie przedsiębiorstwa (MSP) we wszystkich rozwiniętych krajach wytwarzają znaczącą część realnego Produktu Krajowego Brutto (PKB). MSP są również w imponujący sposób otwarte na nowe rozwiązania techniczne i technologiczne, postrzegając innowacje jako wyzwanie oraz szansę. W poszukiwaniu takich rozwiązań, jak również w procesach ich wdrażania, MSP skazane są na współpracę z licznymi partnerami o różnym statusie prawnym, z różnych sektorów, o zróżnicowanej kulturze biznesowej i różnym podejściu do współpracy. Niejednokrotnie taka współpraca staje się dla nich źródłem problemów, a nawet zagrożeń. Metody: W pierwszej części artykułu zawarto przegląd literatury przedmiotu oraz identyfikację i ramową taksonomię obszarów ryzyka współpracy. Druga część zawiera prezentację i dyskusję wybranych wyników badań własnych autorów przeprowadzonych w drugiej połowie 2016 roku na próbie ponad 300 firm z grupy małych i średnich przedsiębiorstw technologicznych (MSPT), wybranych na podstawie określonych filtrów. Celem badań była analiza środowisk współpracy MSPT, ich podejścia do współpracy, oraz postrzegania problematyki ryzyka we współpracy. Wyniki: Analiza obszarów niepewności w otoczeniu MSPT oraz form współpracy pozwoliła zidentyfikować grupę ryzyk mogących wynikać ze współpracy, które ujęto w dwie kategorie: mające charakter ogólny, występujące w każdym MSP, oraz charakterystyczne dla specyfiki MSPT, związane z pozyskiwaniem nowych technologii, współpracą z uczelniami wyższymi, jednostkami badawczo-rozwojowymi, oraz ośrodkami wspierającymi przedsiębiorczość i powołanymi w celu ułatwiania transferu technologii. Badania - uwzględniając silną specyfikę MSPT - dostarczyły interesujących informacji dotyczących typowych sposobów pozyskiwania nowych technologii, kierunków współpracy i relacji z partnerami, oraz czynników i ekspozycji na ryzyko. Wnioski: Artykuł zwraca uwagę na szereg problemów odnoszących się do współpracy MSPT z partnerami w pozyskiwaniu i wdrażaniu nowych technologii. Mając pewne trudności z kontaktami z dużymi jednostkami, MSPT preferują rozwiązania własne i współpracę z firmami o zbliżonej wielkości. To oczywiście nakłada pewne ograniczenia w doborze partnerów a także na dostępność rozwiązań, czyniąc relacje trudniejszymi i bardziej złożonymi. Z przeprowadzonych wywiadów wynika również, że większość MSPT generalnie nie uważa wrażliwości i ekspozycji na ryzyko współpracy za znaczący problem w swojej działalności, jakkolwiek niektóre czynniki ryzyka - np. kwestie prawne czy "miękkie" kompetencje partnerów uznają za istotne. Dalsze badania mogłyby dotyczyć niskiej efektywności współpracy pomiędzy MSPT i instytucjami stanowiącymi naturalne źródło innowacyjnych rozwiązań i powołanych dla zapewniania wsparcia dla tego sektora

Characterisation of mineral composition and strength parameters of varved clays

Varved clays from the valley of Junikowski Stream (Poznan area, Poland) are investigated in this paper. Such clays are characterised by an anisotropic structure, in a form alternate occurrence of thick summer (light) layers and thin winter (dark) layers. Soils forming the light and dark layers have different granulometric compositions. Light layers are built mainly of clays with silt and clays with silt and sand (siCl, sasiCl) while dark ones are composed mainly of clays (Cl). The light and dark layers were tested separately in a direct shear apparatus. The test results revealed differences in strength parameters for soils forming the light and dark layers. The X-ray diffraction analysis was also used to determine the mineral composition of the clay fraction. It is interesting to note that the set of identified clay minerals does not differ very much in both layers. The dominant mineral is illite with presence of kaolinite, smectite and chlorite. A detailed analysis of northern rock pebbles from the terminal moraine of the Poznan glaciation phase and from the outwash plain, which could have been a sourcing area for varved clays, confirmed the largest content of acid igneous rocks in them. Decomposition of the igneous rocks resulted in the dominant presence of illite in the mineral composition of the studied clays