Wind energy is one of the most efficient renewable energies. The most used wind towers are tubularand lattice wind towers. Parts of lattice are easier to transfer, especially in the inland areas. Also, it is easier to build higher lattice tower in order to have more efficient energy conversion in inland areas.However, most of the cross sections for lattice tower are tubular cross sections.This thesis represents the parametric study of polygonal cross section of lattice tower. It consists ofthe numerical analysis based on finite element method (ABAQUS) and analysis based on EN 1993-1-3. The objective of this thesis is to find regular patterns of parametric influences on polygonal crosssection, and to compare them against calculation based on EN 1993-1-3. Also, to find regular patternsof parametric influences on the stiffness of the bolts on the lips.

[No Abstract]

The fabrication of broadband single-mode Cr-doped silica fibers (SMCDSFs) using the fiber drawing-tower method with the modified rod-in-tube technique is demonstrated for the first time. A preform was assembled by using the grown Cr:YAG rod as core and the silica tube as cladding. The outer and inner diameters of the silica tube are 20 and 7 mm, respectively. The initial dimension of the Cr:YAG crystal rod had a length of 0.03 m and a diameter of 500 £gm. The Cr:YAG crystal was grown into a diameter of a 290 £gm with a length of 0.12 m by the LHPG method. The SMCDSFs had a 6 £gm core and a 125 £gm cladding. The transmission loss was 0.08 dB/cm at 1550 nm. The far-field pattern measurements indicated the single-mode characteristic when the propagation wavelength was longer than 1310 nm. In order to solve the interface of core and cladding, a novel rod-in-tube(RIT) perform was employed by inserting the Cr:YAG crystal rod of 0.03m length and 500 £gm diameter into the silica capillary tube, which had the same diameter with the drilled silica rod. The single-mode Cr-doped fibers had successfully been fabricated and the loss had been reduced to 0.03 dB/cm at 1550 nm with a 5 £gm core and a 125 £gm cladding. Furthermore, the SMCDSFs also had the single-mode characteristic when they operated in the optical communication window. The successful fabrication of SMCDSFs may be one step forward towards the achievement of utilizing the SMCDSFs as ultra-broadband fiber optical amplifiers to cover the bandwidths in the whole 1300 to 1600 nm range of low-loss and low-dispersion windows of silica fibers and a broadband source for enabling high resolution in optical coherence tomography (OCT).

The success in fabrication of Cr-doped fibers (CDFs) with fluorescence of Cr3+ by powder-in-tube (PIT) method equipped with drawing-tower process is demonstrated for the first time. The fluorescence intensity of CDFs by fabricated RIT method is weak because the concentration of Cr-ion in Cr:YAG rod is low. However, the fabrication with powder-in-tube (PIT) provides a better solution to improve the concentration of Cr-ion to enhance the fluorescence of CDFs. The Cr-doped powder was composed of CaO-Al2O3-BaCO3-MgO-Cr2O3 as the material of core and then it was poured into the silica tube with outer diameter of 20 mm and inner diameter of 7 mm (20/7) to yield the perform. The CDFs had a 17.5 £gm core and a 125 £gm cladding. The transmission loss was 0.74 dB/cm at 1550 nm. And the fluorescence intensity of Cr3+ between 800~1200 nm was 50 nW/nm. To reduce transmission loss further, we used multi-tubes to raise the ratio of cladding to core. According to the principle of conservation of mass, the core diameter of CDFs was 5 £gm. The transmission loss was improved more than 50% and it reached to 0.135 dB/cm at 1550 nm. Moreover, a single-mode characteristic of CDF was observed when the propagation wavelengths were longer than 1260 nm. The CDFs were successfully fabricated by using a fiber drawing-tower technique with PIT method. The demonstration of CDFs makes it possible as a new generation broadband fiber amplifier, a tunable NIR fiber laser for sensor applications, and a broadband source for high resolution OCT.

Given a string S = {a1, a2, a3, ..., an}, the longest increasing subsequence (LIS) problem is to find a subsequence of the given string such that the subsequence is increasing and its length is maximal. In a previous result, to find the longest increasing subsequences of each sliding window with a fixed size w of a given string with length n can be solved in O(w log log n+OUTPUT) time, where O(w log log n+ w^2) time is taken for preprocessing and OUTPUT is the sum of all output lengths. In this thesis, we solve the problem for finding the longest increasing subsequence of every substring of S. With the straightforward implementation of the previous result, the time required for the preprocessing would be O(n^3). We modify the data structure used in the algorithm, hence the required preprocessing time is improved to O(n^2). The time required for the report stage is linear to the size of the output. In other words, our algorithm can find the LIS of every substring in O(n^2+OUTPUT) time. If the LIS's of all substrings are desired to be reported, since there are O(n^2) substrings totally in a given string with length n, our algorithm is optimal.

¡@¡@Currently, The Cr-doped fibers are grown by LHPG method or drawing-tower technique. The Cr-doped YAG preform was firstly fabricated by a rod-in-tube method. We have successfully fabricated the Cr-doped fibers by using a commercial drawing-tower technique. By employing a negative pressure control in drawing-tower technique on the YAG preform, the Cr-doped fibers with a better core circularity and uniformity, and good interface between core and cladding were fabricated. The core non-circularity was smaller than 3%, the spontaneous emission spectrum showed the bandwidth that approach to 300 nm, and the output power density level have promoted to a few nW/nm. ¡@In this study, we focused on the analysis of dynamic fluorescent characteristics of Cr-doped fibers in order to improve the quality effectively. The lifetimes of Cr4+ fluorescence and concentration of Cr ions were 1.5 £gs and 510 £gg/g, respectively.The concentration of the Cr ions was less than the Cr-doped fibers grown by LHPG method. The high-resolution micrograph showed that there was nano-crystalline structure in the core surrounded by SiO2 amorphous matrix. These nano-particles gathered at the core and formed micrometer clusters, and therefore resulted in high scattering loss around 1.17dB/cm. ¡@¡@In order to improve the Cr-doped fibers quality, reduce propagation loss, and promote the spontaneous emission power density. We have to decrease the temperature and drawing speed in the drawing process Therefore, the new Cr-doped fibers may have the potential for being used as a new generation broadband fiber amplifier to cover the bandwidth of the entire 1.3-1.6 £gm range which exhibit 300 nm usable spectral bands.

In early childhood, planning provides a basis for organizational skills that are useful for future school performance (Perez & Gauvain, 2009). However, research shows that preschoolers’ planning abilities are limited because they often fail to consider task demands, are inefficient at self-monitoring, and are unlikely to use strategies to their advantage (Gardner & Rogoff, 1990). The present study examined whether preschoolers could improve their planning skills by consciously drawing connections between objects and events through the use of verbal self-explanations. A microgenetic design was used in order to repeatedly measure preschoolers’ performance on the Tower of Hanoi (ToH) task over a period of 6 to 8 weeks. Forty-five children between the ages of 4 and 6 years were randomly assigned to 1 of 3 conditions: self-explanation, no self-explanation, and control. Each child was administered a pretest, 3 micro sessions based on condition, and a posttest. In addition to ToH performance, children also were measured on inhibitory control, working memory, short-term memory, and verbal ability at pretest, and on a novel planning task, the Box-ToH, at posttest. Multilevel models were used to analyze the data at the between- and within-person levels. Although no differences were found in ToH performance over time between conditions, preschoolers’ use of self-explanations and strategies were independently related to individual improvements in ToH performance over time. Moreover, preschoolers’ improvements in ToH performance were not reducible to age-related increases, inhibitory control demands, working memory, short-term memory, or verbal ability. Lastly, findings did not support preschoolers’ ability to transfer their knowledge of strategies on the ToH to the Box-ToH. Overall, the present study demonstrated that self-explanations and strategy use are both important predictors of understanding individual changes in planning performance during the preschool years. These findings have important implications in terms of improving preschoolers’ executive function skills and preparing children for early academic success. / Graduate

This is a study of the local development of Irish Tower houses in West Cork that were built between c.1400-1650; these buildings were mostly built by Gaelic clans or Hibernicised Norman families. The study is based on fieldwork and published historical research. A corpus of individual tower house reports provide the raw data. The purpose has been to date these structures by reconstructing the development of their layout. The internal layout of these features is analysed in terms of function; apparent role changes indicated by these are related to changes in Gaelic society known from text-based research. Where possible, inferences are made from the layout of the regional tower houses to better understand the role they played in Gaelic society. The western part of the Survey region has an exceptionally high concentration of fifteenth-century tower houses. These 'raised entrance' tower houses are argued to be an archaic form directly inspired by relic Anglo-Norman hall houses; another ancestral form in the east part of the Survey region is the 'refuge tower'. The role of the tower house and its associated settlements in post-medieval seigneurial settlement and Gaelic/planter interaction is discussed. Sophisticated construction technology, including the systematic use of ratios and units, has to be considered against perceived notions of Gaelic society. The relationship of tower house construction to a wave of Friary construction in the Fifteenth Century is considered; it is argued that an undocumented fifteenth-century economic boom and population expansion in the Gaelic regions was connected with a need for the elite to define land holdings; the latter was an important departure from traditional Gaelic social organisation. The importance of 'castle studies' as a major tool of Irish archaeology is emphasised and possible inter-disciplinary avenues for further research are suggested.

No description available.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of English, General Literature and Rhetoric, 2005. / Includes bibliographical references.