Studies towards the synthesis of nano-diamondoid hydrocarbon cyclohexamantane

Adamantane (C10H16) is the smallest unit cage structure of the diamond crystal lattice. Other diamondoid hydrocarbons are also known, such as diamantane and triamantane. In 2003, the isolation and structural elucidation of a highly symmetrical and remarkably stable “natural product” cyclohexamantane (C26H30) was reported.1 The structure of the nanometer-sized hydrocarbon cyclohexamantane was shown by X-ray crystallography to be the largest fully characterized fragment of the diamond lattice. Higher order diamondoid hydrocarbons may have great potential applications in pharmaceuticals, microelectronics and nanotechnology.2 Prior to von Schleyer’s outstanding synthesis3, adamantane was a rare compound and only available in small quantities. The success to von Schleyer’s synthesis was his appreciation of the fact that adamantane is the most stable hydrocarbon of formula C10H16. He used this knowledge to bring about the Lewis acid catalysed rearrangement (via a sequence of Wagner-Meerwein shifts) of a strained hydrogenated cyclopentadiene dimer (C10H16) to provide adamantane in high yield. Our research goal is to prepare hydrocarbon precursors of formula C26H32 and to study their dehydrogenative rearrangements under acidic conditions as a concise synthetic route to cyclohexamantane (C26H30). Our investigations into two different approaches to build the rearrangement precursors (C26H32) are described in this thesis. In the first approach, a four-directional synthesis of the rearrangement precursor has been examined through Route A and Route B. A more concise approach via the Diels-Alder dimerisation of adamantanocyclopentadiene is also described herein

MODELING OF INTERFACE STRENGTH AS WELL AS INTERFACE DEFORMATION BASED ON NANOMECHANICS AND DEVELOPMENT OF INTERFACE DATABASE SYSTEMS

Biomaterials such as bone and marine exoskeletons have primarily an organic phase (e.g. tropocollagen in bone, chitin in exoskeleton) and an inorganic phase (e.g. hydroxyapatite in bone, calcite in exoskeleton) arranged in a precisely organized multi-level hierarchical arrangement. Interfacial interactions between the organic and inorganic phases significantly affect the mechanical properties of such biomaterials. In presented study, idealized tropocollagen-hydroxyapatite and chitin-calcite interfacial systems are analyzed using a multiscale simulation framework that combines explicit three-dimensional molecular dynamics simulations with finite element simulations that take into account explicit microstructure in a three-dimensional hierarchy. The analyses focus on the shear deformation that occurs in interfaces of such materials when overall three-dimensional hierarchy is subjected to mechanical loading. In order to predict the interface stress magnitude in such systems during deformation, steered molecular dynamics simulations are performed to study the interfacial sliding process between the organic and inorganic phases at the nanoscale. A visco-plastic interfacial sliding model is used to calculate the interface strength and the shear viscosity of each interfacial system. In order to predict the effect of interface on the behavior of the material at the continuum level, a combine

Translation from EFL textbook to classroom: Pedagogy, semiosis and strategy

The modern semiotic world has undergone dramatic changes. Due to the development of technology, a wide range of media and mode are now available to sign makers, facilitating as well as requiring translations within and across semiotic systems. This research takes a social semiotic multimodal approach to study translation practices in educational situations in China. It explores how meaning is translated from EFL textbook to classroom teaching in Chinese universities, from the aspects of pedagogy, semiosis and effects. Focusing on translation, this article analyzes how pedagogy is redesigned in terms of situated practice, overt instruction, critical framing, and transformed practice. Based on the analysis of semiotic resources available in textbook and classrooms, this article discusses the functional loads of modes, patterns of mode combinations, translation categories, and semiotic strategies for realizing multiliteracies pedagogy. Finally, the effects of translation are explored in terms of pedagogy, sentient perception, cognitive process, physical features, and dissemination quality

Location Of Foreign Direct Investment In Peoples Republic Of China, 1979--1993: Application Of A New Locational Framework

This thesis addresses the spatial dimension of foreign direct investment (FDI) with a subnational context with reference to the P.R. China during the period of 1979-1993. The framework for the location of FDI within a subnational context includes three dimensions: (1) the dimension of firm specific variables (FSVs), (2) the dimension of location specific variables (LSVs), and (3) the temporal and dynamic dimension. Within this framework, the general locational models of FDI in China are built, the dynamic changes over time examined, and the effects of country of origin tested. This research also takes the initiative to examine the locational characteristics for the presence of FDI. The presence of FDI is differentiated from the spatial distribution of the total amount of FDI in this research.;The presence of FDI was found to be affected by a city\u27s geographic location as referred to the coast of China. In addition, larger cities were more likely to receive any amount of FDI. Over time, other factors such as urban infrastructure and market potential of a city also increased its chance to become an FDI recipient city.;It was found that the most important factor that affected the spatial distribution of FDI in China was the city size factor. The implication of market potential was evident at later stages of FDI involvement. Government policy also had significant bearing on foreign investors\u27 locational decisions. Its impact, however, lessened and wound down starting in 1991 when FDI in China entered a full-fledged and mature stage. Aside from affecting the spatial distribution, larger size and special policy status of a location also encouraged the presence of FDI.;The effect of country of origin on the presence and the spatial distribution of FDI was evident. Distinct differences were found between FDI from developed countries and that from newly industrialized countries (NICs) such as Hong Kong and Singapore. Investors from NICs were more responsive to policy aspects of a location, while investors from developed countries paid more attention to the built-up merits of a location. These locational differences may be attributed to different industrial compositions as well as different firm specific advantages and characteristics which can be identified with different home countries

Impact of access points on multilane highway accidents

This thesis presents an analysis of reported accidents on multilane highways and regression models that identify the primary explanatory variables that have a significant effect on accident rates midblock to signalized intersections. The analysis was based on traffic and reported accident data provided by New Jersey DOT. The access points per mile and the accident rates per million-vehicle-miles-traveled were analyzed based on a large number of roadway sections which were selected from five NJ State routes. Comparative accident analysis related with traffic and roadway geometric characteristics were performed. The analysis showed that approximately 30% of accidents occurred between intersections, which were primarily attributed to the presence of access points. Among these, about 80% of the accidents were caused by a vehicle moving straight through on the mainline and a turning vehicle from/to an access point. Although nonlinear models show good fit, none of the coefficients of the variables show significant t-statistic values. It can be concluded that no good regression models among those tested provide good estimation of accident rates for multilane highways. A field study was conducted and presented several quantitative variables of speed reduction, delay and percentages of affected vehicles at access points