Arguments and evidence from many related branches of geophysics are used to evaluate the principal hypotheses on the nature of the earth's core. No definite conclusions on the composition of the core are reached. Nevertheless, with improved data from seismology, high pressure physics and planetary astronomy, it should be possible to obtain further insight on the nature of the earth's core on the basis of the arguments summarized in this thesis. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Previous work on Chinese idioms has made significant on both meaning derivation process as well as internal combination patterns. As for teaching idioms at junior high schools, recent textbooks encounter three problems: first, there is no appropriate idiom lists; second, teachers rarely mention their syntactic functions and collocational relations; third, students often use idioms in the wrong way. This study aims to investigate syntactic functions of idioms, by examing the learners¡¦ errors. Chap1 clarifies the definition and the characteristics of idioms. Chap2 prosecutes error analysis. Three types of error are identified: semantic errors, grammar errors and semantic restriction errors which are the most frequent type. With regard to the influence of the familiarity and transparency of idioms, idioms that are low familiar and opaque make learning more difficult. After understanding the learning difficulties, chap4 studies syntactic functions and internal construction of idioms. The main construction type is subject-predicate and the most popular function is predicate. We cannot predict the function of an idiom by its construction, and the argument of an idiom doesn¡¦t affect its function neither. However, the core elements of an idiom is correlate with its function. Chap5 explains learners¡¦ difficulties and designs teaching strategies, such as teaching collocation. Moreover, this paper provides two idiom lists, one for junior high school students, the other for advanced learners.

The silicate "magma trigger" model of volcanism on Io has been evaluated numerically with finite element methods by considering the one-dimensional heat transfer between hot silicate magma and initially cold sulfur. It is found that for the probable range of initial magma temperatures and sulfur temperatures, the contact between silicate magma and a sulfur crust will be 700 (+OR-) 100 K, or approximately the vapor point of elemental sulfur. A silicate magma sill or laccolith on the order of 10 m thick will yield energetic vapor for a period of several weeks to several months depending on the vapor temperature and the amount of convective cooling of the silicate magma that occurs at the silicate-sulfur interface. This model may account for the origin of plumes and possible sulfur flows, as well as for their observed temperatures ((TURN) 600-700K) and lifetimes (several days to a few months). If the conducted heat flow is similar in high and low latitudes, then the low latitude occurrence of plumes may be explained as a result of lower temperatures at higher latitudes. Because the contact temperature of sulfur and silicate magma depends on the pre-existing sulfur temperature, a system in which sulfur vapor temperature is just reached at the equator would not generate sulfur vapor under lower initial sulfur temperatures existing at high latitudes. If the heat flow is higher in high latitudes, then the sulfur crust must be thinner than it is in low latitudes for the model to work as described above. Most of the heat flow from Io may be moved by convection from the interior to the surface, not by conduction. Heat flow may be modulated by the efficient transfer of silicate melts from 40 to 300 km depth, and emplaced as laccoliths at the sulfur-silicate crustal interfaces at a depth of 5-10 km. Sulfur flows, plumes, calderas and other areas of massive radiant heat dissipation continue the convective cycle to the surface. The temperature at the base of the sulfur crust may be less than the melting point of sulfur, and the silicate magma temperature can be as low as 1200 K. Low silicate magma temperatures will occur if the crust of Io is as differentiated as terrestrial rhyolites and trachytes. High alkalies in the Io plasma torus suggest the possibility that the Ionian crust is a highly differentiated silicate.

How plants from a common species pool form community has been considered from a variety of approaches. A promising approach involves the search for assembly rules based on plant functional traits. This approach has potential to provide insight into community and ecosystem processes In this research. a general and simple conceptual model based on life forms and independent of species is used as a framework for assessing the internal structure of plant communities. Plant functional traits are used to identify patterns within and between plant communities in the contrasting environments of Camp Williams, Utah, and Camp Grayling, Michigan. The conceptual model has three different functional types formed by one to three functional groups. A functional group, made up of species with similar life form, is analogous to a vegetation stratum. A functional type, consisting of one or more functional groups. is analogous to a community or vegetation type. Correspondence analysis (CA) and analysis of variance (ANOVA) indicate that richness, species diversity, and trait diversity are essentially independent of functional type and are, for example, fairly consistent regardless of climatic regime or structural complexity. Cover. on the other hand. increases with the number of functional groups in a functional type. Consistent patterns and trends for sets of functional traits support the view that assembly rules may account for internal structure in plant communities. The consistent association of sets of traits with functional groups even in taxonomically dissimilar communities suggests that the functional traits are related to fundamental ecological processes that shape these communities. Ambiguity in some of the results might be explained by extending the analysis to additional installations that replicate the climatic conditions found at Camp Williams and Camp Grayling.

Quartz and orthopyroxene in mafic rocks are commonly observed to be surrounded by fringes of granular pyroxene, and of olivine and clinopyroxene, respectively. This study reproduces the conditions of formation of these textures, and investigates their origins, kinetics and phase relations. Pieces of silica glass or crystals of orthopyroxene were dissolved into tholeiitic and slightly alkaline basalts, suspended from wire loops in an atmospheric pressure quenching furnace, and run for 10 minutes to 32 days at subliquidus temperatures between 1120° and 1190°C and oxygen fugacities close to the QFM buffer. Polished sections of charges were examined primarily by backscattered electron imagery and by microprobe analysis. The textures developed in silica dissolution experiments consist of fringes of elongate skeletal pyroxenes radially arranged around the silica. The pyroxenes first nucleate on the surface of the silica. As dissolution continues, growth continues mostly on existing crystals, rather than by the nucleation of additional crystals. Dissolution rates for silica range from 2.8*10⁻¹¹ to 4.4*10⁻¹⁰ms⁻¹, and are time-independent until growth of the pyroxene fringe hinders transport processes in the melt. This causes dissolution to slow down, until it ceases altogether after 3 to 8 days. A silica-rich layer of melt forms around the surface of charges run at higher temperatures, suggesting that convection driven by variations in surface tension may operate in the charges. The textures developed in orthopyroxene dissolution experiments consist of granular olivines, some of which nucleate on the pyroxene surface, whereas others nucleate within the pyroxene as a result of the decomposition of included phases. With time, olivine crystals become connected and form complex grain shapes. Dissolution rates for orthopyroxene range from 1.7*10⁻¹¹ to 1.2*10⁻⁹ ms⁻¹. At higher temperatures dissolution rates are constant, but at lower temperatures dissolution is time-dependent. Unlike silica dissolution, orthopyroxene dissolution does not cease as a result of continued neocryst growth hindering melt transport, indicating that the fringe remains permeable. For both systems, the neocryst compositions are strongly dependent on the chemistry of the melt formed at the interface between the dissolving crystal and the bulk melt, and the neocrysts may be metastable with respect to the bulk melt. Chemical equilibration of olivine neocrysts with time is observed for longer experiments. Textural equilibration of olivine grains occurs by the processes of liquid-phase sintering in runs longer than 12 hours. Subliquidus dissolution data are applied to textures from natural samples collected from dykes, lava flows and lava lakes, to estimate the residence time of reacted crystals; values range from 0.6 to 208 days for reacted quartz, and from 0.7 to 462 days for reacted orthopyroxenes. The rates of cooling of the magma and the size of the magma body in which the reaction occurred are also estimated.

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Aim: The aim of this study is to evaluate if additive manufacturing (AM) is an appropriate manufacturing method for insoles in comparison to vacuum forming (VF) and subtractive manufacturing (SM) in regards of material properties such as abrasion resistance. Background: Traditionally insoles are manufactured with either VF or SM. AM has been around for some decades but implementation into orthotic and prosthetic (O&P) business has not been accomplished yet. Therefore, the quality of the products produced with AM must be tested in comparison with traditional methods. Method: A comparison of samples for the mentioned manufacturing methods was done with the help of an abrasion testing machine with the standard ASTM G133. Two samples were produced from each manufacturing method and respectively tested for one and two hours. All the samples were weighed before and after the tests with the help of a four decimal scale. The difference in weight before and after the test and coefficient of friction was evaluated. The weight difference was analyzed to see how much material had been removed from the sample. The percentage of wear loss was calculated for each specific sample, both for one hour and two hours of testing. No statistical analysis could be made due to the limited amount of samples and testing time. Result: No statistically significant could be found for either wear loss or the coefficient of friction as mentioned above. Conclusion: A conclusion whether which material having the best abrasion resistance for respectively manufacturing method could not be drawn due to limited results. This study can be seen as a pilot study where the methodology can be used in further studies. Further research on AM needs to be conducted.

Title: Forward and Inverse Modeling of Planetary Gravity and Topography Author: Martin Pauer Department/Institute: Department of Geophysics MFF UK Supervisor of the doctoral thesis: Doc. RNDr. Ondřej Čadek, CSc., Department of Geophysics MFF UK Abstract: The aim of this work was to investigate various mechanisms compensating the observed planetary topography - crustal isostasy, elastic support and dynamic support caused by mantle flow. The investigated models were applied to three different planetary problems. Firstly we applied dynamic compensation model to explain today large-scale gravity and topography fields of Venus and investigate its mantle viscosity structure. The results seem to support not only models with constant viscosity structure but also a model with a stiff lithosphere and a gradual increase of viscosity toward a core. In the second paper several crust compensation models were employed to estimate the density of the Martian southern highlands crust. Since the used methods depends differently on crustal density changes, we were able to provide some constraints on the maximum density of the studied region. In the third application, the strength of a possible ocean floor gravity signal of Jupiter's moon Europa was studied. It turned out that if the long wavelength topography reaches height at...

The tool-less additive manufacturing (AM) or 3D printing processes (3DP) use incremental consolidation of feed-stock materials to construct part. The layer by layer AM processes can achieve spatial material distribution and desired microstructure pattern with high resolution. This unique characteristics of AM can bring custom-made form and tailored functionality within the same object. However, incorporating form and functionality has their own challenge in both design and manufacturing domain. This research focuses on designing manufacturable topology by marrying form and functionality in additively manufactured part using infill structure. To realize the goal, this thesis presents a systematic design framework that focuses on reducing the gap between design and manufacturing of complex architecture. The objective is to develop a design methodology of lattice infill and thin shell structure suitable for additive manufacturing processes. Particularly, custom algorithmic approaches have been developed to adapt the existing porous structural patterns for both interior and exterior of objects considering application specific functionality requirements. The object segmentation and shell perforation methodology proposed in this work ensures manufacturability of large scale thin shell or hollowed objects and incorporates tailored part functionality. Furthermore, a computational design framework developed for tissue scaffold structures incorporates the actual structural heterogeneity of natural bones obtained from their medical images to facilitate the tissue regeneration process. The manufacturability is considered in the design process and the performances are measured after their fabrication. Thus, the present thesis demonstrates how the form of porous structures can be adapted to mingle with functionality requirements of the application as well as fabrication constraints. Also, this work bridges the design framework (virtual) and the manufacturing platform (realization) through intelligent data management which facilitates smooth transition of information between the two ends. / National Science Foundation #OIA-1355466 / National Science Foundation-DMR- MRI #1625704 / National Institute of Health - COBRE: CDTSPC; Grant # P20GM109024 / US-DOT # 693JK31850009CAAP / Dept. of Commerce Research-ND, Award # 17-08-G-191 / CSMS, NDEPSCoR / NDSU Grand Challenge and Development Foundation

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