No description available.

Metamaterials are artificial materials and named by those who work in the microwave material area. According to existing documentation, the metamaterials have relative permittivity and/or relative permeability of values less than 1, including negative values. If the material has negative permittivity and permeability at the same time, the material is also referred to as simultaneously negative medium (DNG medium). Such medium has several features that any natural medium is not equipped with: negative refraction, backward phase, and evanescent wave amplification [5]. Though the medium does not exist in nature, it seems that it can be artificially made through synthesizing metallic insertions inside the natural dielectrics [2]. Due to its unique feature of negative refraction and this feature is not equipped with any reported natural medium, the concept of making perfect lenses with metamaterials has attracted attentions in recent years. However a number of questions need to be answered: How can we quantize the refractive index of the metamaterial given that the permittivity and permeability are known or vice versa; can the metamaterial be made isotropic medium under effects of different incident angles? The answer to the first question will help us to define the dimension of the lenses more efficiently; and the answer to the latter question will help determine if such medium is capable of being used to make lenses. Previous publications from others demonstrated the negative refraction phenomenon of metamaterials though this phenomenon is restricted to a very narrow band [4] [11]. The derivation of the negative refractive index through full-wave simulation and comparison with its value through calculating the simulated negative permittivity and permeability obtained from the simulated scattering matrix have not been reported. The work carried in this thesis fully explored the ways to address this and answer those questions mentioned in previous paragraph. To fully understand the negative refraction effect of metamaterial, the author built a mathematical geometric model to calculate refractive index for rectangular metamaterial slab. With this approach, the refractive index can be obtained provided that incident and peak-receive angle are known. In order to achieve a metamaterial with isotropy property, the author also presented three different types of metamaterial slabs: parallel-arranged, vertical-arranged and cross-arranged slab of capacitive-loaded-loops (CLL) in front of standing probes or posts, which are also called CLL-P slabs. The three arrangements are differentiated by the way unit cell is oriented. With the geometric model, the author obtained refractive indexes for three metamaterial slabs at different incident angles through numerical simulation. The refractive indexes have negative values at all circumstance, which shows the negative refraction phenomena unique to the metamaterial. Unlike the other two CLL-P slabs, the cross-arranged CLL-P slab has near constant refractive index and constant received amplitude regardless of incident angles. This result can be attributed to the symmetrical topology of unit cell in x-y plane. To better explain refractive effects occurred for those three CLL-P slabs, the author also employed a way to calculate the effective permittivity and permeability using scattering matrix. Based on effective permittivity and permeability obtained, the analytical values of refractive indexes have been calculated at resonance point. To check the refractive indexes calculated from two different methods: using Snell's Law based geometric approach and using permittivity/permeability obtained from scattering matrix, two results are compared against each other and agree well. Knowing effective permittivity and permeability is very useful for calculating other parameters of the CLL-P slab such as wave impedance and mismatch loss etc. With all the simulation for parallel-arranged, vertical-arranged, and cross-arranged CLL-P slabs, from simulation results, it is found that the cross-arranged slab has the property of isotropy at different incident angles since the coupling between incident magnetic field and CLL loop will maintain constant. As a validation process, the CLL-P simulation result in parallel waveguide is compared with prior simulation (HFSS) and measurements of refractive focusing of the same structure, and both simulation results agree with measurements. The full-wave simulation tools FEKO that employs the Method of Moments (MoM) is used in the two ways of estimating the negative refractive index of the medium. / Master of Science

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No description available.

No description available.

The United Arab Emirates promotes English as the Medium of Instruction (hereafter referred to as EMI) at tertiary level, which results in many ‘content’ subjects being taught via English. Many institutions employ native English speaking teachers, referred to as either NESTs or NS, for language classes and insist that content teachers operate through this second or other language (L2), to the detriment of ‘non-native’ English speaking teachers in terms of recruitment, and also to the detriment of the students who must study their major subjects via a foreign language. NS teachers are expected to enforce a monolingual classroom environment where English is compulsory and use of the students’ first language is penalised. The U.A.E. is also engaged in spreading this monolingual culture to primary and secondary schools. This mixed methodology study evaluates faculty and management perceptions of the English medium status quo and current concerns within the TEFL/ TESOL profession. As well as surveying faculty opinions via a quantitative questionnaire and then a qualitative appraisal of written comments, interviews with senior management aided a critical appraisal of so-called ‘common-sense’ (Tollefson, 2002) policies and assumptions. The quantitative stage indicated discrepancies between different groups of faculty and the qualitative analysis of written comments and interview data allowed for some, often contradictory, themes to emerge. It will be suggested that many faculty were unconvinced that monolingual classroom environments were efficacious. EMI was challenged on the grounds that studying through another language adds to the learner’s cognitive burden (Troudi, 2009) and makes mastery of content subjects more difficult and contingent upon the student’s language skills. The management interviewees conceded these issues but felt that Content and Language Integrated Learning in English was vital for students who must function in an increasingly globalised market place. Little thought was given to what this might mean for the status of Arabic. It was recommended that Arabic should be reinstated as the medium of content instruction, that English be taught as a foreign language only, and that the way in which English is taught should be critically overhauled to make best use of the diverse skills of NESTs and NNESTs alike. It was also suggested that countries such as the U.A.E. are more likely to achieve the modernity they seek by following a model where the L1 is the language of instruction, while English fulfils its parallel role as a foreign language and international lingua-franca.

In view of the fact that clay has not been used so extensively or wisely in elementary art education as the generally recognized importance of the material seems to justify, the purpose of this study is to explore the possibilities of clay as a creative medium and to determine which of the many ceramic techniques are most suitable for use by pupils in the upper elementary grade.

Several optical information processing tasks are implemented using photorefractive BSO as a dynamic holographic medium. The physical basis for the mechanism which allows the implementation of these devices is studied. The properties of BSO which make it particularly attractive as a processing medium are highlighted, and experimental results are presented to demonstrate its practical limitations. An extensive study is presented of the influence of optical bias on the grating formation characteristics. This leads to a documentation of the optimum conditions for transient enhancement of a beam diffracted from such a grating. This transient enhancement can be controlled to provide ideal characteristics for the implementation of transient devices such as a novelty filter. A novelty filter utilising this transient enhancement is subsequently demonstrated. It exhibits good temporal discrimination through the choice of suitable external optical conditions, and the use of digital thresholding. The overall device operates at T.V. frame rates. Results are also presented of various optical correlators using BSO. These include the optical intensity correlator. The unique properties of the intensity correlator are stressed by practical demonstration. Specifically, the relative intolerance of the intensity correlator (compared with coherent correlators) to the position of the various components is demonstrated. Also, the spatially incoherent readout light allows the use of a low-optical quality liquid crystal television (LCTV) as a low-cost spatial light modulator. Output results are then presented from the correlator using the LCTV as a dynamic readout device. This provides an updateable hologram as the reference of the correlator which is interrogated at frame rates by the LCTV. Finally, the temporal discrimination of the novelty filter is combined with the character recognition ability of the intensity correlator. This produces an optical processor which will recognise a particular object but will only register it at the output stage when it is moving.

As a part of loyalty programs in marketing or as incentive plans in companies, mediums have attracted considerable interest from marketing and organizational behavior researchers. Previous studies focused mainly on the effects of mediums on people’s choices and not on the role of moderators of a medium effect. The goal of the present thesis is to study two such moderators namely the numerosity of a medium and the cognitive complexity of mediums. In this study, after a thorough theoretical analysis, experimental data is analyzed to explore the relation between numerosity and cognitive complexity of a medium on individuals’ efforts. Our findings suggest that the medium effect is stronger when a medium is more numerous. Also, a more cognitively complex medium makes the mediums more effective.

Using the characteristics of small-business firms and of their owners, the information from both the joint credit information center and loan auditors, and logistic models, this study analyzes the determinants of the approval of small-business loans made by credit officers. The study also examines whether these determinants are significant in the logistic models of loan default and provide suggestions to credit officers for approving small-business loans. The main findings of this study are as follows. 1. Some specific proxy variables for the characteristics of small-business firms and of their owners and information from both the joint credit information center and loan auditors are significant determinants in the logistic models of loan approval. Their importance or significance will differ when the sample loans are categorized on the basis of sales. 2. The significant determinants in the logistic models of loan default are also significant determinants in the logistic models of loan approval. The result indicates that credit officers are able to effectively consider some factors contributing to loan default when they make loan decisions. Thus, the credit officers perform well in managing credit risk when approving loans. 3. The number of significant determinants in the logistic models of loan approval is far greater than that in the models of loan default. The finding implies that credit officers may place more stringent criteria in approving loans and lose some profitable business opportunities. 4. Establishing different criteria on the basis of sales when approving loans can facilitate the increase in the rate of loan approval and decrease in the rate of loan default. 5. The information from loan auditors plays an important role in the approval of loans to firms with small sales. It seems not to be the case in the approval of loans to firms with large sales. Therefore, it is better that loan auditors be equipped with abundant knowledge of various industrial sectors and be given well on-job training. Moreover, the performance of loan auditors should be independent with the number or size of loans.