Optimization studies and fabrication of an Fe-Mm(Dy)-B permanent magnet using powder metallurgy techniques

Call number: LD2668 .T4 CHE 1987 C57Master of ScienceChemical Engineerin

Video features predicting engagement in climate change education

Climate change is a substantial threat. Awareness-raising and education are key goals. Social media provide an opportune context for the delivery of science education content. However, little research has examined which video features elicit engagement on climate change. This project focused on YouTube and aimed to identify the most predictive factors of video engagement on the topic of climate change. Video engagement was defined as an algorithmic composite of outcomes derived through YouTube API such as the number of views and number of comments, among other measures. A search of YouTube videos revealed an original list of 183 videos on climate change. A random selection of 90 videos was manually coded on engagement predictor variables (i.e., video type, presenter type, audio-visual elements, video content, and other features). Results indicated that most YouTube videos are consistent with a widely accepted scientific viewpoint on the topic although their scientific quality and video argumentation content do not appear to affect video engagement. Rather, presenter and video characteristics associated with entertainment emerge as more specific predictors influencing video engagement. Social media can be used as a fruitful avenue for imparting education on pertinent issues such as climate change although it is important to consider ways of balancing quality education with entertainment features

Cryptic genomic imbalances in patients with de novo or familial apparently balanced translocations and abnormal phenotype

<p>Abstract</p> <p>Background</p> <p>Carriers of apparently balanced translocations are usually phenotypically normal; however in about 6% of <it>de novo </it>cases, an abnormal phenotype is present. In the current study we investigated 12 patients, six <it>de novo </it>and six familial, with apparently balanced translocations and mental retardation and/or congenital malformations by applying 1 Mb resolution array-CGH. In all <it>de novo </it>cases, only the patient was a carrier of the translocation and had abnormal phenotype. In five out of the six familial cases, the phenotype of the patient was abnormal, although the karyotype appeared identical to other phenotypically normal carriers of the family. In the sixth familial case, all carriers of the translocations had an abnormal phenotype.</p> <p>Results</p> <p>Chromosomal and FISH analyses suggested that the rearrangements were "truly balanced" in all patients. However, array-CGH, revealed cryptic imbalances in three cases (3/12, 25%), two <it>de novo </it>(2/12, 33.3%) and one familial (1/12, 16.6%). The nature and type of abnormalities differed among the cases. In the first case, what was identified as a <it>de novo </it>t(9;15)(q31;q26.1), a complex rearrangement was revealed involving a ~6.1 Mb duplication on the long arm of chromosome 9, an ~10 Mb deletion and an inversion both on the long arm of chromosome 15. These imbalances were located near the translocation breakpoints. In the second case of a <it>de novo </it>t(4;9)(q25;q21.2), an ~6.6 Mb deletion was identified on the short arm of chromosome 7 which is unrelated to the translocation. In the third case, of a familial, t(4;7)(q13.3;p15.3), two deletions of ~4.3 Mb and ~2.3 Mb were found, each at one of the two translocation breakpoints. In the remaining cases the translocations appeared balanced at 1 Mb resolution.</p> <p>Conclusion</p> <p>This study investigated both <it>de novo </it>and familial apparently balanced translocations unlike other relatively large studies which are mainly focused on <it>de novo </it>cases. This study provides additional evidence that cryptic genomic imbalances are common in patients with abnormal phenotype and "apparently balanced" translocations not only in <it>de novo </it>but can also occur in familial cases. The use of microarrays with higher resolution such as oligo-arrays may reveal that the frequency of cryptic genomic imbalances among these patients is higher.</p

Whole genome amplification with SurePlex results in better copy number alteration detection using sequencing data compared to the MALBAC method

Current whole genome amplification (WGA) methods lead to amplification bias resulting in over-and under-represented regions in the genome. Nevertheless, certain WGA methods, such as SurePlex and subsequent arrayCGH analysis, make it possible to detect copy number alterations (CNAs) at a 10 Mb resolution. A more uniform WGA combined with massive parallel sequencing (MPS), however, could allow detection at higher resolution and lower cost. Recently, MALBAC, a new WGA method, claims unparalleled performance. Here, we compared the well-established SurePlex and MALBAC WGA for their ability to detect CNAs in MPS generated data and, in addition, compared PCR-free MPS library preparation with the standard enrichment PCR library preparation. Results showed that SurePlex amplification led to more uniformity across the genome, allowing for a better CNA detection with less false positives compared to MALBAC amplified samples. An even more uniform coverage was observed in samples following a PCR-free library preparation. In general, the combination of SurePlex and MPS led to the same chromosomal profile compared to a reference arrayCGH from unamplified genomic DNA, underlining the large potential of MPS techniques in CNA detection from a limited number of DNA material

AM-FM Texture Image Analysis of the Intima and Media Layers of the Carotid Artery

Abstract. The purpose of this paper is to propose the use of amplitude modulation-frequency modulation (AM-FM) features for describing atherosclerotic plaque features that are associated with clinical factors such as intima media thickness and a patient&apos;s age. AM-FM analysis reveals the instantaneous amplitude (IA) of the media layer decreases with age. This decrease in IA maybe attributed to the reduction in calcified, stable plaque components and an increase in stroke risk with age. On the other hand, an increase in the median instantaneous frequency (IF) of the media layer suggests the fragmentation of solid, large plaque components, which also lead to an increase in the risk of stroke. The findings suggest that AM-FM features can be used to assess the risk of stroke over a wide range of patient populations. Future work will incorporate a new texture image retrieval system that uses AM-FM features to retrieve intima and intima media layer images that could be associated with the same level of the risk of stroke

Electronic and structural properties at the interfaces between graphene and molecular acceptors/donors

In dieser Arbeit wurde die Austrittsarbeit von Graphen, einer vielversprechenden Elektrodenmaterial für (opto)- elektronische Bauteile, durch die Adsorption von luftbeständigen konjugierten organischen Molekülen (KOMs), welche als Akzeptoren und Donatoren fungieren, modifiziert. Die Eigenschaften der Valenz- und Rumpfniveaus sowie die Austrittsarbeitsmodifikation der vakuumverdampften KOMs wurden mit Photoelektronenspektroskopie (PES) untersucht, während die Orientierung der KOMs mit Röntgen-Nahkanten-Absorptions-Spektroskopie (NEXAFS) aufgeklärt wurde. Die Austrittsarbeit von Graphen auf Quartz (G/Qu) lässt sich auf maximal 5.7 eV und minimal 3 eV anpassen, welches aus einem Ladungstransfer direkt an der Grenzfläche resultiert, der keine Ausbildung von kovalenten Bindungen zwischen der molekularen Monolage und dem Graphen beinhaltet. Zudem, für den starken molekularen Akzeptor Hexaazatriphenylen-Hexacarbonitril (HATCN) verläuft die Austrittsarbeitserhöhung über eine Orientierungsänderung der Moleküle im Monolagenbereich. Für alle anderen auf G/Qu abgeschiedenen Akzeptoren (Donatoren) wurde beobachtet, dass der Ladungstransfer eine positive (negative) Oberflächen-ladungsdotierung der Graphen-Schicht bewirkt, welches in einer Austrittsarbeitserhöhung (-erniedrigung) resultiert. Letztere ließ sich jeweils in zwei Beiträge zerlegen: (a) Verschiebung des Vakuumniveaus durch einen Grenzflächendipol an der KOM/Graphen-Grenzfläche und (b) Verschiebung des Fermi-Niveaus durch Oberflächenladungstransferdotierung der Graphen-Schicht. Weiterhin wurde der molekulare Akzeptor Hexafluoro-tetracyano napththoquinodimethan (F6TCNNQ) sowohl auf G/Qu als auch auf Graphen auf Kupfer abgeschieden, wobei sich herausstellte, dass der Ladungstransfer im ersteren Fall vom Graphen stammt, und im letzteren von der Kupferunterlage. Die Ergebnisse werden von Dichtefunktionaltheorieberechnungen gestützt und tragen erheblich zum Verständnis von Graphen/KOM-Grenzflächen bei.In this thesis, the work function of graphene, a promising electrode for (opto)electronic devices was modified by adsorption of air-stable conjugated organic molecules (COMs) that act as strong molecular acceptors or donors. The valence and core level properties, together with the work function modification of the vacuum-deposited COMs on graphene were investigated with photoelectron spectroscopy (PES), while the orientation of COMs was studied with near edge X-ray fine structure spectroscopy (NEXAFS). The work function of graphene-on-quartz (G/Qu) is modified up to 5.7 eV and down to 3 eV as a result of charge transfer (CT) occurring right at the interface, which does not invoke covalent bond formation between the molecular monolayer and the graphene. In addition to the CT, in the case of the molecular acceptor hexaazatriphenylene-hexacarbonitrile (HATCN), the work function increase proceeded via a density-dependent re-orientation of the molecule in the monolayer regime. For all the other tested molecular acceptors (donors) deposited on graphene-on-quartz, the CT was observed to induce positive (negative) surface CT doping of the graphene layer, leading to a work function increase (decrease) and was disentangled into two contributions: (a) shift of the Vacuum level due to the formation of an interface dipole at the COM/graphene interface and (b) shift of the Fermi level of the graphene due to the surface CT doping. Additionally, the molecular acceptor hexafluoro-tetracyanonapththoquinodimethane (F6TCNNQ) was deposited on both G/Qu and graphene-on-copper, where the CT was found to originate from graphene and copper support respectively. The findings were supported by density functional theory calculations and significantly add to a fundamental understanding of graphene/COM interfaces

Emergency Escape Manoeuvre of a Faulty Truck in a Platoon Formation Moving in Highway

The platooning of trucks provides significant benefits in the existing transportation systems regarding social, economic and environmental aspects. Due to the platoon's high dependence on sensors, it is critically important to have fault-tolerant countermeasures that deal efficiently with failures by achieving minimal risk condition. This thesis tackles designing an emergency escape manoeuvre for a faulty truck that has lost its ability to monitor the driving environment while moving in a platoon formation on a highway. A fallback strategy is proposed that leads the faulty truck to park on the shoulder of the road and allows the rest of the platoon participants to continue their journey. To solve this problem, first, a functional platooning system should be designed. Therefore, a nonlinear bicycle dynamic model is employed, while a new Bidirectional (BD) Cooperative Adaptive Cruise Control (CACC) system is utilized for control purposes. The emergency escape manoeuvre has to be pre-computed and ready to be triggered when the failure occurs, as concerning defined specifications, limitations and constraints. It is generated using a quintic splines methodology, while a new optimization approach regarding the minimization of jerk peaks is adopted, enhancing the efficiency of the design procedure. Furthermore, a gap-closing controller is employed and tuned accordingly to reform the platoon after the faulty truck abandons the formation. Moreover, a suitable decision logic is defined to achieve smooth transition among regular performance and fallback state at both platoon and inter-vehicle level. The functionality of each component is firstly evaluated individually, based on specific performance metrics. Finally, all the mentioned components are put together and the fallback strategy that executes emergency escape manoeuvre in platoon context is derived. Several simulation tests illustrate proof of principle for the proposed framework. It is shown that the proposed strategy indeed achieves minimal risk condition for the faulty truck achieving minimal tracking errors. A global applied strategy is adopted for the gap-closing controller by making healthy follower(s) travel with the maximum possible acceleration. At the same time, the leading truck of the formation maintains a constant speed until the time gap between them becomes $0.8s$, before the switch back to the CACC, to complete this action as fast as possible and safety issues in the driving performance. Additionally, the CACC system is evaluated to ensure that the string stability criterion is satisfied in the mode of operation. Moreover, a virtual leader mechanism is introduced to fill in faulty truck's blind spot in the road that arise from the sensor failure. It is shown that it can provide a sufficient window of movement for the platoon before switching to the fallback strategy.Mechanical Engineering | Systems and Contro

A BIM-based framework for forecasting and visualizing seismic damage, cost and time to repair

eWork and eBusiness in Architecture, Engineering and Construction - Proceedings of the European Conference on Product and Process Modelling 2010 2010, Pages 33-38A methodology is presented for integrated and automated forecasting of damage assessment, cost estimating, scheduling and of 3D/4D visualizations for post-earthquake building rehabilitation. The proposed methodology is based on the integration of Building Information Modelling (BIM) and Assembly-Based Vulnerability (ABV) techniques. ABV is a framework for evaluating the seismic vulnerability and performance of structures on a building-specific basis, utilizing seismic analysis techniques to determine the structural response of a building. The methodology used accounts for structural and non-structural building components and corresponding fragility curves, and subsequently applies BIM-based techniques to automate the generation of cost estimates, activity schedules as well as 3D/4D visualizations of the associated rehabilitation work. © 2010 Taylor & Francis Group, London