37 resultados para Ice industry

em Helda - Digital Repository of University of Helsinki


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The purpose of this study was to extend understanding of how large firms pursuing sustained and profitable growth manage organisational renewal. A multiple-case study was conducted in 27 North American and European wood-industry companies, of which 11 were chosen for closer study. The study combined the organisational-capabilities approach to strategic management with corporate-entrepreneurship thinking. It charted the further development of an identification and classification system for capabilities comprising three dimensions: (i) the dynamism between firm-specific and industry-significant capabilities, (ii) hierarchies of capabilities and capability portfolios, and (iii) their internal structure. Capability building was analysed in the context of the organisational design, the technological systems and the type of resource-bundling process (creating new vs. entrenching existing capabilities). The thesis describes the current capability portfolios and the organisational changes in the case companies. It also clarifies the mechanisms through which companies can influence the balance between knowledge search and the efficiency of knowledge transfer and integration in their daily business activities, and consequently the diversity of their capability portfolio and the breadth and novelty of their product/service range. The largest wood-industry companies of today must develop a seemingly dual strategic focus: they have to combine leading-edge, innovative solutions with cost-efficient, large-scale production. The use of modern technology in production was no longer a primary source of competitiveness in the case companies, but rather belonged to the portfolio of basic capabilities. Knowledge and information management had become an industry imperative, on a par with cost effectiveness. Yet, during the period of this research, the case companies were better in supporting growth in volume of the existing activity than growth through new economic activities. Customer-driven, incremental innovation was preferred over firm-driven innovation through experimentation. The three main constraints on organisational renewal were the lack of slack resources, the aim for lean, centralised designs, and the inward-bound communication climate.

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The basis for this study was in poor attractiveness of the wood products industry among young people as a field to study and work in. The purpose was to produce new information of how to improve the relationship between young people and the wood products industry in order to better attract young people with different relational orientation. A survey was conducted among students of comprehensive schools and students of wood industry at vocational schools selected by systematic cluster sampling. The final sample consisted of 613 students. The study combined the theories and concepts of relationships, communication and trust of several disciplines. In addition, it applied theories of relationship marketing, stakeholders, publics, involvement and concepts of reputation and values. It studied the central relational elements in the form of antecedents, relationship state and its consequences. The study examined, how young people with different background and level of interest perceive wood industry as a field to study and work in from relational point of view, what are the central deficiencies in perceived relational elements and what are the public relations activities enhancing the relationship between wood industry and young people with less and high interest in the sector. The results indicate poor visibility of the wood industry among young people: unfamiliarity with the industry and unawareness of the opportunities to study in the field. It appeared that instead of increasing only information sharing, interactive communication in different forms is needed. The study also suggests that behaviors of the industry sector advancing perceived trustworthiness are of crucial importance. Moreover, the wood industry needs to pay attention to its behaviors and communication also among other stakeholder groups, especially the media, as reputation plays an important role in building up trust and satisfaction between young people and the sector. Finally, the less and highly interested young people were found to assess the relationship partly through different relational elements. In order to develop the relationship with highly interested young people they should be regarded clearly as future employees of the wood industry through activities affirming that they are desired and valued employees in the sector. Further, openness of information disclosure, whether concerning current situation or future prospects, seems to increase credibility and attractiveness of the wood industry. Highly interested young people were also found to appreciate socially responsible activities. The less interested young people seem to be insecure about the reliability of the wood industry as an employer, as well as, its ability and interest to invest in young people s skills. In addition,involvement in issues relevant for young people was found crucial in enhancing the relationship with the less interested young people.The conclusions of the study provide tools for enhancing the attractiveness of the wood industry among young people not only to the industry itself, but also to its advocates, teachers and student counselors of comprehensive and vocational schools, authorities and policy makers.

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Palaeoenvironments of the latter half of the Weichselian ice age and the transition to the Holocene, from ca. 52 to 4 ka, were investigated using isotopic analysis of oxygen, carbon and strontium in mammal skeletal apatite. The study material consisted predominantly of subfossil bones and teeth of the woolly mammoth (Mammuthus primigenius Blumenbach), collected from Europe and Wrangel Island, northeastern Siberia. All samples have been radiocarbon dated, and their ages range from >52 ka to 4 ka. Altogether, 100 specimens were sampled for the isotopic work. In Europe, the studies focused on the glacial palaeoclimate and habitat palaeoecology. To minimise the influence of possible diagenetic effects, the palaeoclimatological and ecological reconstructions were based on the enamel samples only. The results of the oxygen isotope analysis of mammoth enamel phosphate from Finland and adjacent nortwestern Russia, Estonia, Latvia, Lithuania, Poland, Denmark and Sweden provide the first estimate of oxygen isotope values in glacial precipitation in northern Europe. The glacial precipitation oxygen isotope values range from ca. -9.2±1.5 in western Denmark to -15.3 in Kirillov, northwestern Russia. These values are 0.6-4.1 lower than those in present-day precipitation, with the largest changes recorded in the currently marine influenced southern Sweden and the Baltic region. The new enamel-derived oxygen isotope data from this study, combined with oxygen isotope records from earlier investigations on mammoth tooth enamel and palaeogroundwaters, facilitate a reconstruction of the spatial patterns of the oxygen isotope values of precipitation and palaeotemperatures over much of Europe. The reconstructed geographic pattern of oxygen isotope levels in precipitation during 52-24 ka reflects the progressive isotopic depletion of air masses moving northeast, consistent with a westerly source of moisture for the entire region, and a circulation pattern similar to that of the present-day. The application of regionally varied δ/T-slopes, estimated from palaeogroundwater data and modern spatial correlations, yield reasonable estimates of glacial surface temperatures in Europe and imply 2-9°C lower long-term mean annual surface temperatures during the glacial period. The isotopic composition of carbon in the enamel samples indicates a pure C3 diet for the European mammoths, in agreement with previous investigations of mammoth ecology. A faint geographical gradient in the carbon isotope values of enamel is discernible, with more negative values in the northeast. The spatial trend is consistent with the climatic implications of the enamel oxygen isotope data, but may also suggest regional differences in habitat openness. The palaeogeographical changes caused by the eustatic rise of global sea level at the end of the Weichselian ice age was investigated on Wrangel Island, using the strontium isotope (Sr-87/Sr-86) ratios in the skeletal apatite of the local mammoth fauna. The diagenetic evaluations suggest good preservation of the original Sr isotope ratios, even in the bone specimens included in the study material. To estimate present-day environmental Sr isotope values on Wrangel Island, bioapatite samples from modern reindeer and muskoxen, as well as surface waters from rivers and ice wedges were analysed. A significant shift towards more radiogenic bioapatite Sr isotope ratios, from 0.71218 ± 0.00103 to 0.71491 ± 0.00138, marks the beginning of the Holocene. This implies a change in the migration patterns of the mammals, ultimately reflecting the inundation of the mainland connection and isolation of the population. The bioapatite Sr isotope data supports published coastline reconstructions placing the time of separation from the mainland to ca. 10-10.5 ka ago. The shift towards more radiogenic Sr isotope values in mid-Holocene subfossil remains after 8 ka ago reflects the rapid rise of the sea level from 10 to 8 ka, resulting in a considerable reduction of the accessible range area on the early Wrangel Island.

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The seasonal occurrence of sea ice that annually covers almost half the Baltic Sea area provides a unique habitat for halo- and cold temperature-tolerant extremophiles. Baltic Sea ice biology has more than 100 years of tradition that began with the floristic observation of species by the early pioneers using light microscopic techniques that were the only thing available at the time. Since the discovery of life within sea ice, more technologies have become available for taxonomy. Electron microscopy and genetic evidence have been used to identify sea ice biota revealing increased numbers of taxa. Meanwhile ecologists have used light microscopic cell enumeration in addition to the chemical and physical properties of sea ice in attempts to explain the food web structure of sea ice and its functions. Thus, during the Baltic winter, the sea ice hosts more abundant and diverse microbial communities than the water column beneath it. These communities are typically dominated by autotrophic diatoms together with a diverse assortment of dinoflagellates, auto- and heterotrophic flagellates, ciliates, metazoan rotifers and bacteria, which are mostly responsible for the recycling of nutrients. This thesis comprises ecological and systematic studies. In addition to the results of the previous studies carried out on landfast ice, the data presented here provide new insight into the spatial distribution of pelagial sea ice, which has remained largely unexplored. The studies reveal spatial heterogeneity in the pelagial sea ice of the Gulf of Bothnia. There were mismatches in chlorophyll-a concentrations and in photosynthetic efficiencies of the communities studied. The temporal succession was followed and experimental studies performed investigating the community responses towards increased or decreased light in landfast ice in the Gulf of Finland. The systematic studies carried out with established dinoflagellate cultures revealed a new resting cyst belonging to common sea ice dinoflagellate, Scrippsiella hangoei (Schiller) Larsen 1995. The cyst can be used to explain the overwintering of this species during prolonged periods of darkness. The dissimilarities and similarities in the material isolated from the sea ice called for description of a new subspecies Heterocapsa arctica ssp. frigida. The cells obtained in the cultured material were unlike those of the previously described species, necessitating description of ssp. frigida. As a result of its own unique habitus, the subspecies had been noted by Finnish taxonomists during the past three decades and thus its annual occurrence and geographical distribution in the Baltic Sea. This illustrates how combining ecology and systematics increases our understanding of organisms.

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Pack ice is an aggregate of ice floes drifting on the sea surface. The forces controlling the motion and deformation of pack ice are air and water drag forces, sea surface tilt, Coriolis force and the internal force due to the interaction between ice floes. In this thesis, the mechanical behavior of compacted pack ice is investigated using theoretical and numerical methods, focusing on the three basic material properties: compressive strength, yield curve and flow rule. A high-resolution three-category sea ice model is applied to investigate the sea ice dynamics in two small basins, the whole Gulf Riga and the inside Pärnu Bay, focusing on the calibration of the compressive strength for thin ice. These two basins are on the scales of 100 km and 20 km, respectively, with typical ice thickness of 10-30 cm. The model is found capable of capturing the main characteristics of the ice dynamics. The compressive strength is calibrated to be about 30 kPa, consistent with the values from most large-scale sea ice dynamic studies. In addition, the numerical study in Pärnu Bay suggests that the shear strength drops significantly when the ice-floe size markedly decreases. A characteristic inversion method is developed to probe the yield curve of compacted pack ice. The basis of this method is the relationship between the intersection angle of linear kinematic features (LKFs) in sea ice and the slope of the yield curve. A summary of the observed LKFs shows that they can be basically divided into three groups: intersecting leads, uniaxial opening leads and uniaxial pressure ridges. Based on the available observed angles, the yield curve is determined to be a curved diamond. Comparisons of this yield curve with those from other methods show that it possesses almost all the advantages identified by the other methods. A new constitutive law is proposed, where the yield curve is a diamond and the flow rule is a combination of the normal and co-axial flow rule. The non-normal co-axial flow rule is necessary for the Coulombic yield constraint. This constitutive law not only captures the main features of forming LKFs but also takes the advantage of avoiding overestimating divergence during shear deformation. Moreover, this study provides a method for observing the flow rule for pack ice during deformation.

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Polar Regions are an energy sink of the Earth system, as the Sun rays do not reach the Poles for half of the year, and hit them only at very low angles for the other half of the year. In summer, solar radiation is the dominant energy source for the Polar areas, therefore even small changes in the surface albedo strongly affect the surface energy balance and, thus, the speed and amount of snow and ice melting. In winter, the main heat sources for the atmosphere are the cyclones approaching from lower latitudes, and the atmosphere-surface heat transfer takes place through turbulent mixing and longwave radiation, the latter dominated by clouds. The aim of this thesis is to improve the knowledge about the surface and atmospheric processes that control the surface energy budget over snow and ice, with particular focus on albedo during the spring and summer seasons, on horizontal advection of heat, cloud longwave forcing, and turbulent mixing during the winter season. The critical importance of a correct albedo representation in models is illustrated through the analysis of the causes for the errors in the surface and near-surface air temperature produced in a short-range numerical weather forecast by the HIRLAM model. Then, the daily and seasonal variability of snow and ice albedo have been examined by analysing field measurements of albedo, carried out in different environments. On the basis of the data analysis, simple albedo parameterizations have been derived, which can be implemented into thermodynamic sea ice models, as well as numerical weather prediction and climate models. Field measurements of radiation and turbulent fluxes over the Bay of Bothnia (Baltic Sea) also allowed examining the impact of a large albedo change during the melting season on surface energy and ice mass budgets. When high contrasts in surface albedo are present, as in the case of snow covered areas next to open water, the effect of the surface albedo heterogeneity on the downwelling solar irradiance under overcast condition is very significant, although it is usually not accounted for in single column radiative transfer calculations. To account for this effect, an effective albedo parameterization based on three-dimensional Monte Carlo radiative transfer calculations has been developed. To test a potentially relevant application of the effective albedo parameterization, its performance in the ground-based retrieval of cloud optical depth was illustrated. Finally, the factors causing the large variations of the surface and near-surface temperatures over the Central Arctic during winter were examined. The relative importance of cloud radiative forcing, turbulent mixing, and lateral heat advection on the Arctic surface temperature were quantified through the analysis of direct observations from Russian drifting ice stations, with the lateral heat advection calculated from reanalysis products.