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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Pojiva a maltové směsi na bázi síranu vápenatého / Binders and Mixtures Based on Calcium Sulfate

Hanáček, Jan January 2016 (has links)
This Diploma Thesis deals with the research and advancements in the field of sulphate binders, especially the anhydrite binder. The theoretical part of the thesis is dedicated to the fundamentals of sulphate binders and anhydrite binders. Its second part also introduces standard requirements for screed coatings together with technological methods of their application. Practical part of the thesis looks at the research and production of anhydrite binder with special emphasis on self-levelling compounds. Various types of plasticizers were used in these compounds and their effectiveness and final product quality are compared.
52

Comparing Academic Vocabulary List (AVL) Frequency Bands to Leveled Biology and History Texts

Crandall, Lynne 01 April 2019 (has links)
For decades, teachers and language learners have been concerned about matching the difficulty level of texts to the proficiency level of learners in order to achieve comprehensible input, which leads to effective learning. Some leveling systems and research use word lists as part of their leveling processes, particularly the Academic Word List. The Academic Vocabulary List (AVL) has not been explored yet as a leveling tool, so this study aims to address this lack of research by examining how the AVL words vary in cumulative frequency bands and also in separate frequency bands with regard to level and topic. The AVL was divided into 5 frequency bands and compared against corpora of biology and U.S. history texts at the elementary, junior high, high school, and university levels. Results showed that the biology texts had a higher percentage of total AVL tokens than the history texts did, suggesting that the AVL may be more suitable for some disciplines than others. For the cumulative bands, Bands 1 through 3 proved to have the highest percent deltas, suggesting that words 1 to 800 are the most useful to learn. Looking at each separate band, Bands 1 and 2 had the highest percent of AVL tokens at the high school level, implying that the words of these bands are especially valuable for learners at this level. The university level had the highest percentage for Bands 3 through 5. There was no statistical significance for any band concerning the factor of the relationship between topic and level, but there was statistical significance for the factor of proficiency level at every level. For the factor of topic, there was significance for every band except Band 3. For each band, the elementary and junior high texts were generally similar to each other concerning the AVL tokens found in them. High school and university texts were similar to each other for Bands 1 and 2 but were not similar to each other for Bands 3 through 5.
53

Opakovaná GPS měření na polygonu Tetčice a jejich interpretace / Repeated GPS measurements at Tetčice polygon and its interpretation

Dvořák, Jiří January 2012 (has links)
This thesis deals with monitoring shifts in the vicinity of the village Tetčice. The site is located at the interface of geomorphological units. Monitor the area is done in stages and methods of using GPS and precise leveling. Points tested are expected movements in places the earth's crust, which are stabilized on the pillars in order to avoid possible negative effects. The work builds on results from previous measurements.
54

The importance of material properties on the bendability of Q/QT steels

Laschke, Erikka January 2012 (has links)
This master thesis work has been carried out at the company SSAB EMEA in Oxelösund which is a global leader in quenched and tempered high-strength steel. The aim is to examine the importance of the material properties for the bendability of the specific steel grade Weldox. There are many conditions for various applications such as mobile cranes and vehicles that need to be fulfilled in order for the material to be approved, where one main prerequisite is the bendability. It is very important to be able to bend the material without the occurrence of cracks. The purpose of this work has therefore been to investigate and try to find the relationship between the material properties and the critical bending radius. Furthermore has another aim been to find the most suitable treatment process for the composition of this specific steel grade.The work was divided into two parts, where the first part was to examine two equally treated Weldox 960 plates that differed significantly in properties such as bendability and toughness. In the second part seven different plates of the steel grade Weldox 1100 have been investigated where all the plates were treated in various ways. The leveling of the plates was performed in two different ways; either according to the standard leveling or to the property affected leveling (ERIK). The experimental part includes tests such as bending, hardness, toughness, tensile and inclusions measurements.The results have shown that the most significant material properties affecting the bendability are the yield strength and the purity close to the plate surface. Leveling with ERIK as the last treatment step has shown that the toughness of the material can be increased but it does not affect the bendability for these specific steel grades. Other properties such as hardness, ultimate tensile strength and elongation have no major impact on the bendability for this specific composition. The most suitable treatment proved to be tempering at 200°C as the last step in the process chain.
55

Ex vivo biomechanical comparison of four center of rotation angulation based leveling osteotomy fixation methods

Whitney, Melody E 09 December 2022 (has links)
Thirty-two canine tibiae with patellae and patellar tendons were harvested from 17 skeletally mature cadavers. Each tibia was randomly allocated to a construct group: plate and pin (Plate), plate with countersink compression screw (HCS), plate with tension band (TB), or plate with HCS and TB (HCSTB). Samples were loaded by distraction until failure. The stiffness, yield load, and ultimate load were compared between each fixation method. No difference in stiffness of the constructs was detected between groups. Yield load and ultimate load for the HCSTB group was greater than the TB group, the HCS group, and the Plate group. CBLO fixation augmented with a TB and HCS provided a stronger construct that withstood a greater yield load and ultimate load than either augmentation strategy alone. Augmenting a CBLO fixation with a TB and a HCS can provide increased construct strength.
56

Study on ongoing subsidence in Uppsala City using Sentinel-1 radar data

Fryksten, Jonas January 2019 (has links)
Many cities in Sweden are partly located on clay and because of that, some urban city centres are undergoing significant subsidence. To measure subsidence in cities, precise leveling has been the traditional technique, but the interest for the Persistent Scatter InSAR (PSI) technique has increased in the last years, in this application. With the PSI technique, a mm-accuracy can be obtained and the analyses can be done over large areas. In this study, a validation between the PSI and the precise leveling techniques was performed for a selection of buildings located in areas that are facing great subsidence. A correlation between the subsidence rate achieved in the PSI analyses and near-surface soil type was also done, to easier identify risk zones. The city of Uppsala was chosen as study area, because it is partly built on deep layers of clay and the consulting company Bjerking AB has established a leveling network with metal pegs on many buildings. One ascending and one descending PSI analysis was performed, with Sentinel-1 data from the period mid-2015 to mid-2019, and the PSI analyses were done in SARPROZ. After the PSI analyses, comparative permanent scatters (PS) points and metal pegs were identified creating validation pairs. 15 different validation pairs were identified in four different objects, which was one or two buildings. The PSI analyses showed that Uppsala is undergoing significant subsidence in some parts, with an annual rate of about 6 mm/year in the line-of-sight (LOS) direction, which corresponds to about 7.5 mm/year in the vertical direction. The areas of greatest deformation were exclusively found on postglacial clay. The standard deviation of the time series were calculated around their linear regression lines, which was a measure of how temporal coherent the points were. The mean of this standard deviation for the PS points in the 15 validation pairs was 1.5 mm. This standard deviation increased to 2.3 mm in the time series where the direction was transformed from LOS to vertical and where the movements were in respect to the benchmarks. Between the PSI and the precise leveling techniques, in the validation, the vertical subsidence rate differed less than 1 mm/year in all validation pairs and the mean of all differences was 0.56 mm/year. Based on these results, Sentinel-1 data can measure urban subsidence in a satisfactory way, when the PSI technique is applied.
57

The Effect of Stifle Angle on Stifle Kinematics following TPLO: An in vitro Experimental Analysis

Johnson, Kelly Ann 12 May 2010 (has links)
Objective: To determine the ability of the Tibial Plateau Leveling Osteotomy (TPLO) to restore normal joint kinematics in a cranial cruciate ligament (CrCL)-deficient stifle through a loaded range of motion. Methods: Paired pelvic limbs from 12 dogs were compared in an in vitro biomechanical study. Each limb was placed in a custom designed jig at 120° of stifle extension under an axial load of 20% body weight. Electromagnetic motion tracking sensors were placed on the distal femur and proximal tibia. A force was applied at approximately 10 N/sec to mimic the action of the quadriceps muscle. Force application allowed the limb to move from 120° to maximal extension. Positional data was acquired at 60 points/second. Each limb was tested under normal, CrCL-deficient, and TPLO-treated conditions. Results: The TPLO failed to normalize CTT within the CrCL-deficient stifle; however, values trended towards intact values throughout the range of motion. No significant differences were noted in internal rotation in any of the three conditions from 120° – 137°. Hyperextension values did not differ significantly between conditions. Conclusion: Data from this biomechanical model suggests that the TPLO fails to neutralize CTT throughout a loaded range of motion. Internal rotation and hyperextension values were not found to differ significantly between intact, CrCL-deficient and TPLO repaired stifles. The effectiveness of the TPLO in restoring normal biomechanics is more significant at greater angles of flexion. / Master of Science
58

Μεθοδολογία βελτιστοποίησης πολλαπλών στόχων για την κατανομή πόρων στα τεχνικά έργα

Καϊάφα, Σοφία 04 September 2013 (has links)
Ο χρονικός προγραμματισμός αποτελεί τον ακρογωνιαίο λίθο του συστήματος διαχείρισης των έργων και, λόγω της σημασίας του, τα τελευταία χρόνια αποτελεί πεδίο εντατικής έρευνας τόσο σε επίπεδο ακαδημαϊκών εργασιών όσο και στην επιχειρηματική κοινότητα. Το χρονοπρόγραμμα συνδέεται με δύο θεμελιώδη χαρακτηριστικά των έργων: την διάρκεια ολοκλήρωσης των εργασιών (άρα και τον χρόνο διάθεσης του έργου προς χρήση) και το κόστος κατασκευής. Η σημασία του χρονικού προγραμματισμού αποκτά πρόσθετο ειδικό βάρος αν αναλογιστεί κανείς τις μεγάλες απαιτήσεις, την πολυπλοκότητα, το μέγεθος, την διαφοροποίηση, τις κατασκευαστικές λεπτομέρειες, τα ιδιαίτερα χαρακτηριστικά απόδοσης (προδιαγραφές ποιότητας, ασφάλειας, αντοχής, περιβαλλοντικής μέριμνας, κ.λπ.) αλλά και τις ανάγκες των χρηστών των τεχνικών έργων. Η διαθεσιμότητα και η κατανομή των ανθρώπων, των μηχανημάτων, των υλικών και του εξοπλισμού που απαιτούνται για την εκτέλεση ενός έργου, όπως εύλογα προκύπτει, επηρεάζουν καταλυτικά τον χρονικό προγραμματισμό. Όλα τα παραπάνω συνθέτουν τους απαιτούμενους πόρους ή, διαφορετικά, τα μέσα παραγωγής για την εκτέλεση του έργου. Οι διαφορετικές επιλογές κατανομής των πόρων, ενδέχεται να οδηγήσουν σε σημαντική αύξηση ή μείωση του κόστους υλοποίησης, στην καθυστέρηση ή γενικά στην χρονική μετακίνηση εργασιών, στην επιλογή εναλλακτικών πόρων ή τρόπων εκτέλεσης, στην κατάτμηση των δραστηριοτήτων (εφόσον υπάρχει η δυνατότητα) ή ακόμα και στον συνολικό αναπρογραμματισμό του έργου. Για την επίλυση των προβλημάτων κατανομής των πόρων, έχουν αναπτυχθεί πολλές μεθοδολογίες που βασίζονται σε μαθηματικές ή ευρετικές και μετα-ευρετικές προσεγγίσεις. Κάθε κατηγορία επίλυσης περιλαμβάνει διακριτές υποκατηγορίες και έχει συγκεκριμένες απαιτήσεις (προϋποθέσεις), οι οποίες προφανώς επηρεάζουν την αποτελεσματικότητα του μηχανισμού επίλυσης και φυσικά το αποτέλεσμα. Κοινό στοιχείο σε όλες αυτές τις περιπτώσεις είναι η πολυπλοκότητα του προβλήματος που αντιμετωπίζεται και το πλήθος των παραμέτρων και των περιορισμών, συνήθως συγκρουσιακών, που επηρεάζουν τις τελικές λύσεις. Στην παρούσα Διατριβή αναλύεται ακριβώς αυτή η προβληματική της κατανομής των πόρων στα τεχνικά έργα και οι πιο διαδεδομένες μεθοδολογικές και τεχνικές προσεγγίσεις. Η έρευνα εστιάζει στην βελτιστοποίηση προβλημάτων πολλαπλών στόχων που προσομοιάζουν στα πραγματικά δεδομένα. Τα εν λόγω προβλήματα χαρακτηρίζονται από την ύπαρξη περιορισμών στην διαθεσιμότητα των πόρων, συμπεριλαμβανομένου του χρόνου, την απαίτηση πολλαπλών πόρων (διαφορετικές κατηγορίες μέσων παραγωγής) για την υλοποίηση του έργου, την ύπαρξη γενικευμένων σχέσεων διαδοχής ανάμεσα στις δραστηριότητες που συνθέτουν το έργο και την δυνατότητα εναλλακτικών τρόπων εκτέλεσης των δραστηριοτήτων. Λαμβάνοντας υπόψη τις παραπάνω παραμέτρους, σχεδιάζεται ένα μοντέλο βελτιστοποίησης στην βάση των επιμέρους όρων κόστους των έργων και αναπτύσσεται μία εφαρμογή Τεχνητής Νοημοσύνης με χρήση Γενετικού Αλγορίθμου σε γλώσσα προγραμματισμού Visual Basic for Applications στο φιλικό περιβάλλον του Microsoft Excel. Οι επιδόσεις του αλγορίθμου σε ικανό πλήθος προβλημάτων για τα οποία γνωρίζουμε εκ των προτέρων την βέλτιστη λύση (ή μία πολύ καλή λύση κοντά στην βέλτιστη) είναι ιδιαίτερα ικανοποιητικές. Τα συμπεράσματα αξιολόγησης της προτεινόμενης μεθοδολογίας βελτιστοποίησης είναι θετικά, με αποτέλεσμα η γενίκευση του μοντέλου σε μεγαλύτερα ή και πιο σύνθετα προβλήματα να παρουσιάζει εξαιρετικό ενδιαφέρον. / --
59

Od stachanovců k volné sobotě. Pojetí práce v socialistickém Československu šedesátých let 20. století / From the Stakhanovite-Movement toward a Free Saturday. The Idea of Labor in Socialist Czechoslovakia of the 1960s

Keller, Filip January 2014 (has links)
This paper outlines the concept of labour in socialist Czechoslovakia of the 1960s. It examines on discourses of social and economic reforms and that of the post-Stalin era. The focus lays on main social, economic and ideological categories on which those projects based, on extent of their construction as well as on shifting the emphasis between their particular elements. The paper concerns above all conceivable relation of the newly shaped discourse to effort to reconstitute social differentiation and to overcome the social leveling of the previous Stalin era. An attempt will be made to connect Honnet's theory of recognition with G. Cohen's concept of egalitarian justice. From that perspective, the paper will examine historical tranformations of conceptions of justice, division of labour, a social ethos of different social groups (particullary the educated intelligentsia), legitimacy of given forms of redistribution etc.
60

Estudo biomecânico ex vivo da tensão do ligamento patelar à flexão do joelho com as técnicas de avanço da tuberosidade tibial (TTA) e osteotomia niveladora do platô tibial (TPLO), comparadas com tíbias não osteotomizadas / Ex vivo biomechanical evaluation of the tension of the patellar ligament to stifle flexion after tibial tuberosity advancement (TTA) and tibial plateau leveling osteotomy (TPLO), compared with tibia not osteotomized

Caquías, Daniela Fabiana Izquierdo 10 May 2013 (has links)
O reparo do ligamento cruzado cranial (LCCr) tem sido motivo de preocupação e pesquisas para desenvolver técnica cirúrgica efetiva. Recentemente novas técnicas tem se proposto a reestabelecer a biomecânica e função do joelho, chamadas de técnicas dinâmicas, entre elas Tibial Plateau Leveling Osteotomy (TPLO) e Tibial Tuberosity Advancement (TTA). Embora efetivas, várias são as complicações relatadas, e uma delas é o espessamento e desmite patelar, mais frequente com a técnica de TPLO, mas recentemente também relatada para a técnica de TTA. Vários foram os mecanismos propostos para explicar este fenômeno, embora a causa continue desconhecida. Baseado nisso é que a nossa pesquisa teve como objetivo avaliar de forma biomecânica ex vivo, as mudanças na tensão do ligamento patelar submetido às técnicas de TPLO e TTA, quando comparadas entre elas e com membros pélvicos sem osteotomia (íntegro e RLCCr). Foram testados de forma biomecânica ex vivo dez pares de membros pélvicos de cães entre dois a sete anos de idade e pesos entre 25 a 35 kg, sem predileção de raça ou sexo. As peças foram submetidas à carga de 30% do peso corporal, e testadas em três situações diferentes: a primeira com a articulação fêmoro-tíbio-patelar íntegra, numa segunda etapa com RLCCr, e por último com as técnicas de osteotomia, respeitando a regra, membros pélvicos direitos com TTA e membros pélvicos esquerdos com TPLO, e cada uma delas foi testada em duas situações de ângulos, a primeira 145 graus na articulação fêmoro-tíbio-patelar e 135 graus na articulação tíbio-társica e uma segunda situação invertendo os valores. Os dados foram submetidos a testes pareados não paramétricos de Friedman e Wilcoxon. Em quanto a força do ligamento patelar os resultados permitiram concluir que não existe diferença significativa entre o grupo íntegro e RLCCr, que existe diferença entre as técnicas de TTA e TPLO, quando comparadas com a situação íntegro e RLCCr e que existe diferença de força do ligamento patelar entre TPLO 145 versus TPLO 135 e entre TTA 145 versus TTA 135. / Cranial cruciate ligament repair (RLCCr) has been the focus of research to develop an effective surgical technique. Currently new dynamic techniques such as Tibial Plateau Leveling Osteotomy (TPLO) and Tibial Tuberosity Advancement (TTA) have been proposed to restore the biomechanical knee function. Several complications have been reported despite of technique effectiveness. Patellar ligament inflammation and desmitis are usually reported as complication for TPLO but it was also reported for TTA. Several mechanisms have been proposed to explain this phenomenon but the cause remains unknown. Based on this complication, our objective was to evaluate the patellar ligament tension changes in the TPLO and TTA using an ex vivo model comparing both techniques one each other and with normal hind limbs. The sample population was ten pairs of cadaveric hind limb from dogs weighing 25 to 35 kg and with two to seven years of age without any predilection for breed or sex. The pieces were axially loaded using a material testing machine with 30% body weight in three different situations. The first test was performed with the CCL intact followed by the second test with the LCC transection and finally with osteotomy techniques for the third test. TPLO and TTA were always performed in the left and right hind limb respectively. The tests were conducted in two variations of angles joints. The first variation maintained a stifle angle of 145 degrees with the tibio-tarsal angle of 135 degrees and the second variation had inverted the values between these joints. Data were analyzed using Friedman and Wilcoxon test with repeated measures. In much the strength of the patellar ligament the results showed that there is no significant difference between the group intact and RLCCr that exists between the different techniques TTA and TPLO, when compared with the situation of integrity and RLCCr and strength that exists apart from the ligament TPLO patellar between 135 and 145 versus TPLO between TTA 145 versus 135.

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