Die vorliegende Bachelorarbeit befasst sich mit dem Learning Tools Interoperability Standard, kurz LTI Standard. Ziel ist es hierbei nicht nur den LTI Standard an sich in seiner Anwendung zu evaluieren sondern ebenso eine eigene Implementierung dieser Schnittstellendefinition zu erarbeiten. Um eine solche Implementierung zu erreichen wird sich Eingangs intensiv mit dem Standard in seinen verschiedenen Versionen auseinandergesetzt und anschließend der praktische Einsatz dieser Schnittstelle durch die Evaluation bestehender Kopplungsmöglichkeiten erprobt. Zur Evaluierung wird eine Auswahl von Lehrumgebungen und Lernanwendungen, bei welchen im Anschluss unter verschiedenen Gesichtspunkten die Kopplungen betrachtet und diskutiert werden.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Objective: This study was conducted to determine the resistance to wear and effectiveness of Opal®Seal (Opal Orthodontics by Ultradent, South Jordan, UT, USA) against enamel demineralization in comparison to L.E.D. Pro Seal® (Reliance Orthodontic Products, Itasca, IL, USA). Background: Development of white spot lesions (WSL) is a primary concern during fixed orthodontic treatment. With poor oral hygiene during orthodontic therapy, it is almost inevitable that enamel demineralization will occur and WSLs will be seen clinically. Numerous materials have demonstrated successful prevention of WSLs, including topical varnishes and sealants, gels, pastes and bonding agents. The newly developed sealant Opal Seal is claimed by the manufacturer to prevent demineralization and subsequent WSLs from forming during orthodontic treatment. To evaluate the effectiveness of Opal Seal, we tested and compared it to Pro Seal, which has proven to be successful at WSL prevention and is, like Opal Seal, a fluoride-releasing, light-cured, low viscosity filled resin sealant. Methods: A total of 48 non-carious extracted human premolar teeth were divided into 3 groups representing one of the following topical treatments: no treatment (C), Opal Seal (OS) or L.E.D. Pro Seal (PS). Each group was subdivided into either T1 or T2 time interval groups (C1, C2, OS1, OS2, PS1 and PS2) and teeth were subjected to 10,000 or 20,000 simulated brush strokes, respectively, followed by exposure to an acidic solution for 96 hours. Teeth were examined macroscopically for product wear and assessment of WSL development and then sectioned for quantitative examination with polarized light microscopy. Results: Visual assessment revealed wear of L.E.D. Pro Seal in 62.5% of the PS2 teeth following exposure to toothbrush abrasion and acidic challenge. No L.E.D. Pro Seal or Opal Seal wear was found in any PS1 or OS teeth, respectively. WSLs involving 50-100% of the exposed enamel surface developed in all control teeth and 37.5% of PS teeth had WSLs involving less than 50% of their enamel surface. These WSLs were visible as small, white, isolated points. No visible WSLs were found in any teeth in the OS group. A Fisher's Exact test was used to evaluate any differences in demineralization within groups over time. The results indicate a significant difference in the number of lesions found at T1 compared to T2 in the PS group (p = 0.003). A non-parametric Kruskal-Wallis test using a Wilcoxon test for all multiple comparisons was conducted to evaluate any differences among the treatment groups for change in depth of demineralization (µm) at two different time points. PS and OS groups were found to have significant differences in average lesion depth compared to the control groups at T1 and T2 (pConclusions: Our results showed that both Opal Seal and L.E.D. Pro Seal reduce enamel demineralization when teeth are subjected to simulated toothbrush abrasion and an acidic environment over time. Opal Seal provided superior protection of the enamel surface and demonstrated complete wear resistance and prevention of demineralized lesion development in our experimental groups.

The aim of the diploma thesis was to analyze qualitative outages in the production of gears for a gear pump and to minimize them. The largest amount of outages was caused by the burning of the surface during face grinding. After analyzing the current state of production there were created some suggestions to avoid this issue. Also there was found some space to speed up the whole process. Suggestions to eliminate burning have been tested with minimal impact on production. The reduction of outages for burned surface was achieved and also the cycle time was shortened. Those suggestions will be implemented in serial production.

Latino English learners (ELs), among the largest student population in the United States K-12 school system, continue to lag behind their English-proficient peers. They also tend to attend segregated schools, have less-qualified teachers, and lack access to rigorous curriculum, including the arts. Museum education departments have increasingly sought to fill the gap in arts education for underserved populations. This mixed methods study explored the degree to which teaching artists (TAs) from a large metropolitan museum are effectively addressing the art education needs of Latino ELs. The dissertation study occurred in two phases. Phase 1 included quantitative analysis of observations of the TAs using the numeric components and ancedotal evidence of the Observation Protocol for Academic Literacies. Phase 2 consisted of semistructured interviews with the participants. Findings of the study indicate that while TAs can improve instruction in terms of providing materials of students’ native language and providing opportunities to transfer skills between their primary and the target language, they nevertheless use numerous strategies for effective English language instruction. This can inform museum education departments on effective teaching practices of ELs, an area of study that has almost no scholarship.

Since the East Texas area has many minerals in the categories which yield semiprecious stones of commercial value--jasper, wood agate, wood opal, and silicified stone, the author undertook this study to determine: (1) the extent which these minerals could be utilized as sources for gems; (2) the equipment necessary for cutting and polishing the stones; and (3) the techniques for finishing the gems.

No description available.

<div>Self-assembled templates allow the creation of many complex arrays of nanostructures, which would be extremely difficult and expensive, if not impossible, to realize using any of the other available fabrication techniques. The complexity of these advanced nanostructures, synthesized using the various template assisted electrodeposition techniques, can be controlled to nanometer scale range by tuning the structural properties of the template, which is achieved by adjusting its various growth parameters during the self-assembly process.</div><div>Electrodeposition allows the creation of arrays of various metallic and semiconducting nanostructures. Monitoring the electrodeposition conditions permit the creation of single crystalline nanostructures of a particular material, or the formation of heterostructures using multiple electrodeposition steps. This work demonstrates the template assisted electrodeposition of vertically aligned nanowire arrays, both straight and branched, of metals, and a direct bandgap, III-V semiconductor, indium antimonide (InSb), which has one of the smallest known bandgap of any material. The template assisted electrodeposition of metallic, and InSb inverse opal (IO) structures is also shown, and the fabrication of a novel zipper shaped nanostructure by laser photomodification of a Ni IO structure is reported.</div><div>The optical characterization of the various nanostructures realized in this work have been examined. The results from this work confirm the ability to tune the optical spectra of nanostructures of the same material with similar volume fill fractions by structural modulation, where the different optical responses can be attributed to the structural differences of the actual structure as opposed to the material properties of the solid.</div>

Three-dimensional macroporous structures (‘opals’ and ‘inverse opals’) can be produced by colloidal crystal templating, one of the most intensively studied areas in materials science today. There are several potential advantages of lithium-ion battery electrodes based on inverse opal structures. High electrode surface, easier electrolyte access to the bulk of electrode and reduced lithium diffusion lengths allow higher discharge rates. Highly open structures provide for better mechanical stability to volume swings during cycling. Silicon is one of the most promising anode materials for lithium-ion batteries. Its theoretical capacity exceeds capacities of all other materials besides metallic lithium. Silicon is abundant, cheap, and its use would allow for incorporation of microbattery production into the semiconductor manufacturing. Performance of silicon is restricted mainly by large volume changes during cycling. The objective of this work was to investigate how the inverse opal structures influence the performance of silicon electrodes. Several types of silicon-based inverse opal films were synthesised, and their electrochemical performance was studied. Amorphous silicon inverse opals were fabricated via chemical vapour deposition and characterised by various techniques. Galvanostatic cycling of these materials confirmed the feasibility of the approach taken, since the electrodes demonstrated high capacities and decent capacity retentions. The rate performance of amorphous silicon inverse opals was unsatisfactory due to low conductivity of silicon. The conductivity of silicon inverse opals was improved by crystallisation. Nanocrystalline silicon inverse opals demonstrated much better rate capabilities, but the capacities faded to zero after several cycles. Silicon-carbon composite inverse opal materials were synthesised by depositing a thin layer of carbon via pyrolysis of a sucrose-based precursor onto the silicon inverse opals in an attempt to further increase conductivity and achieve mechanical stabilisation of the structures. The amount of carbon deposited proved to be insufficient to stabilise the structures, and silicon-carbon composites demonstrated unsatisfactory electrochemical behaviour. Carbon inverse opals were coated with amorphous silicon producing another type of macroporous composites. These electrodes demonstrated significant improvement both in capacity retentions and in rate capabilities. The inner carbon matrix not only increased the material conductivity, but also resulted in lower silicon pulverisation during cycling.

Three-dimensional macroporous structures (‘opals’ and ‘inverse opals’) can be produced by colloidal crystal templating, one of the most intensively studied areas in materials science today. There are several potential advantages of lithium-ion battery electrodes based on inverse opal structures. High electrode surface, easier electrolyte access to the bulk of electrode and reduced lithium diffusion lengths allow higher discharge rates. Highly open structures provide for better mechanical stability to volume swings during cycling. Silicon is one of the most promising anode materials for lithium-ion batteries. Its theoretical capacity exceeds capacities of all other materials besides metallic lithium. Silicon is abundant, cheap, and its use would allow for incorporation of microbattery production into the semiconductor manufacturing. Performance of silicon is restricted mainly by large volume changes during cycling. The objective of this work was to investigate how the inverse opal structures influence the performance of silicon electrodes. Several types of silicon-based inverse opal films were synthesised, and their electrochemical performance was studied. Amorphous silicon inverse opals were fabricated via chemical vapour deposition and characterised by various techniques. Galvanostatic cycling of these materials confirmed the feasibility of the approach taken, since the electrodes demonstrated high capacities and decent capacity retentions. The rate performance of amorphous silicon inverse opals was unsatisfactory due to low conductivity of silicon. The conductivity of silicon inverse opals was improved by crystallisation. Nanocrystalline silicon inverse opals demonstrated much better rate capabilities, but the capacities faded to zero after several cycles. Silicon-carbon composite inverse opal materials were synthesised by depositing a thin layer of carbon via pyrolysis of a sucrose-based precursor onto the silicon inverse opals in an attempt to further increase conductivity and achieve mechanical stabilisation of the structures. The amount of carbon deposited proved to be insufficient to stabilise the structures, and silicon-carbon composites demonstrated unsatisfactory electrochemical behaviour. Carbon inverse opals were coated with amorphous silicon producing another type of macroporous composites. These electrodes demonstrated significant improvement both in capacity retentions and in rate capabilities. The inner carbon matrix not only increased the material conductivity, but also resulted in lower silicon pulverisation during cycling.

abstract: With the increasing penetration of Photovoltaic inverters, there is a necessity for recent PV inverters to have smart grid support features for increased power system reliability and security. The grid support features include voltage support, active and reactive power control. These support features mean that inverters should have bidirectional power and communication capabilities. The inverter should be able to communicate with the grid utility and other inverter modules. This thesis studies the real time simulation of smart inverters using PLECS Real Time Box. The real time simulation is performed as a Controller Hardware in the Loop (CHIL) real time simulation. In this thesis, the power stage of the smart inverter is emulated in the PLECS Real Time Box and the controller stage of the inverter is programmed in the Digital Signal Processor (DSP) connected to the real time box. The power stage emulated in the real time box and the controller implemented in the DSP form a closed loop smart inverter. This smart inverter, with power stage and controller together, is then connected to an OPAL-RT simulator which emulates the power distribution system of the Arizona State University Poly campus. The smart inverter then sends and receives commands to supply power and support the grid. The results of the smart inverter with the PLECS Real time box and the smart inverter connected to an emulated distribution system are discussed under various conditions based on the commands received by the smart inverter. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2017