An ultralight aircraft based airborne geophysical system was developed and operated by the Council for Geoscience during the period 1997-2004. The aim of this project was to collect geophysical data at lower cost and higher resolution than was possible using conventional airborne systems. This dissertation describes the development of the radiometric systems used in the ultralight airborne survey project. During the course of the study, a number of obstacles to the successful collection and processing of radiometric data with the ultralight-mounted systems were encountered. These are described and solutions proposed. To facilitate the development hardware systems and processing methods, a Monte Carlo simulation method was developed to produce spectra containing realistic signal and noise components. This method was applied to the selection of detector materials and the specification of detector sizes as well as being used to simulate large spectral data sets for the development and testing of processing and calibration procedures. Radiometric data follow a Poisson Distribution, with the signal to noise ratio being dependent on the count rate recorded, which, in turn, depends on the size of the detector used. The ultralight aircraft were capable of carrying a detector one eighth the size of that used in conventional systems. To allow for the use of the smaller detector, the noise adjusted singular value decomposition (NASVD) processing technique was employed. While this technique is commonly applied in noise-reduction, the original application, namely the determination and mapping of spectral components was also utilised. iii During the course of the study no suitable calibration facilities were available inside South Africa. This necessitated the development of a spectral stripping method, utilising a technique generally applied to much higher resolution spectral data collected under laboratory conditions. Simulation studies and practical application showed that this method performs well, in some cases outperforming the conventional stripping method. The method is also applicable to the study of anthropogenic radionuclides, where suitable calibration facilities are generally unavailable. An alternative to the conventional method of altitude correction was also applied to the radiometric data collected with the ultralight-mounted systems. Using simulated data, a spectrometer based on a bismuth germanate (BGO) detector was designed and constructed. This material is significantly denser than the more usual thallium activated sodium iodide used for detector fabrication and has a higher effective atomic number, giving it a greater photopeak efficiency. However the poor light production of this scintillation material results in a poorer energy resolution than a conventional detector. Initial tests using small BGO detectors were promising and a larger detector was acquired and tested. Unfortunately the poor energy resolution and high cost of BGO detectors led to the conclusion that they did not offer the advantages initially hoped for. Nevertheless a number of successful surveys were flown using the BGO detector. Ultralight-mounted systems were found to be ideal for small surveys where high spatial resolution is required. The ultralight systems were successfully applied to the detection of radioactive pollution on a number of sites in the Witwatersrand and related gold fields and one site where anthropogenic radionuclide contamination was present. In some cases, the data could be compared to data collected using a conventional airborne radiometric system. Here the ultralight- mounted systems were found to perform satisfactorily, albeit with a poorer signal to noise ratio except where adverse flying conditions necessitated flying at high altitude. The strengths, weaknesses and potential applications of ultralight-mounted airborne radiometric systems are discussed.

This research fabricated and tested various graphene-related 1D, 2D and 3D materials. We described how using specifically designed graphene foam (GF) as templates can transform its unique structures and excellent properties to new materials. Graphene, GF, Polypyrrole (PPY), Polyaniline (PANI), PPY-GF, PANI-GF, SiC foam, SiC nanowires and SiC nanoflakes will be described in this thesis. The chemical vapour deposition method was used to produce graphene and GFs. PPY-GF, PPY, PANI and PANI-GF were prepared by both chemical and electrochemical (Chronopotentiometry) methods. SiC foams were produced by a low-cost carbothermal reduction of SiO with GF, and then the SiC nanoflakes were separated from SiC nanowires and purified via a multistep sonication process. The synthesised materials were characterised by a variety of techniques such as SEM, EDX, XRD, TEM, Raman, AFM and TGA. The electrochemical properties of the materials were measured in a three electrode cell using cyclic voltammetry (CV), galvanostatic charge-discharge and A.C impedance spectroscopy techniques. The mechanical properties of the GF and SiC foams were investigated by conducting compression tests under in-situ SEM imaging. The as-produced graphene in this research was few layer graphene with layer number varies from 2 to 15. The GFs was found to be extremely light weight with an average density value of 5 mg cm-3. Using GF as electrode materials for supercapacitors, we obtained 100% capacity retention after 10,000 of charge-discharge cycles. The PPY-GF composite electrode exhibited an outstanding specific capacitance of 660 Fg-1, which is superior to the performance of most of the existing PPY-CNT, PPY-graphite and PPY-Graphene electrodes reported to date. In contrast to the PPY which shows a big structure degradation and a 30% capacity loss after only hundreds of CV cycles, the PPY-GF composite showed nearly 100% capacity retention after 6,000 cycles of charge-discharge. Our post-test characterisations showed no structural loss for the GF and PPY-GF. The excellent pseudocapacitive performance of the electrodes was found to be related to three key parameters: the open porosity feature of the GF which provides short pathways for ion diffusion and charge transportation, the dual charge storage mode in the composite, and the excellent mechanical properties of the GF. Due to its high flexibility and void spaces, the GF played successfully the role as a holder and stabilizer for the electroactive materials in protecting them from any structural degradation during the repeated ion intercalation-de-intercalation processes. In the SiC project, we have successfully created extremely light-weighted SiC foams with a density range of 9-20 mg cm-3, with various shapes, by using the GF as templates. These foams are the lightest reported SiC structures, and they consist of hollow trusses made from 2D SiC and long 1D SiC nanowires growing from the trusses, edges and defect sites. The 1D SiC nanowires, being confirmed as 3C-structure, appeared in a variety of shapes and sizes and are highly flexible; the 2D SiC is hexagonal, and upon breakup the resulting 2D nanoflakes have an average size of 2 µm and a thickness value of 2-3 nm which is 5-9 layers of SiC. They, to the best of our knowledge, are probably the thinnest and largest reported SiC flakes. Ultimately, in this research we have successfully produced two extremely lightweight and simultaneously strong foams: the GF and SiC foam. We have explored the GFs by efficiently addressing a key issue in the cycle life of energy storage devices, by creating an ideal architecture of such 3D GF-based electrodes. We have developed a completely novel 3D SiC structure made from continuously linked 2D layered SiC reinforced with 1D SiC nanowires. In-situ compression studies have revealed that both the GF and SiC foams can recover significantly, up to 85% in the case of GF, after compression strain exceeding 70%. The SiC foam did not experience any dramatic failure under the compression loads, as do in conventional ceramics. Compared with most existing lightweight foams of similar density, the present 3D SiC exhibited superior compression strengths and an significantly enhanced strength-to-weight ratio.

No description available.

Thesis (LL.M.). / Written for the Faculty of Law. Title from title page of PDF (viewed 2009/06/17). Includes bibliographical references.

Thesis (M.S.)--Ohio University, November, 2006. / Title from PDF t.p. Includes bibliographical references.

This work describes digitalization and creation of ultralight aircraft 3D model in order to create accurate moulds for fuselage lamination. Right choice of technology is based on background research. Designed procedures are described in detail as well as used equipment, hardware and software. Objective of this project is application of available methods of digitalization to create 3D aircraft model and its usage for accurate mould design.

The aim of this diploma thesis is to design a new high-wing aircraft for the company TL ultralight using the structural elements from another models from their portfolio. The design is created with an emphasis on crew comfort and cabin ergonomics. The first part of the thesis focuses on the description of the basic requirements for the aircraft and its classification in aviation regulations. It also contains a research part of competing types and currently produced type, which the proposed aircraft should replace in the company's portfolio. Then follows the characteristics of the individual parts of the airframe, the specification of the parts, which will be used from another types from portfolio, and parts which will be completely designed. Great emphasis is placed on the layout of the interior and its design and ergonomic. The proposed aircraft then demonstrates theoretical calculations of basic performances and a preliminary mass analysis. In the end, the benefits of the newly designed aircraft are evaluated with respect to the competing types.

This thesis deals with the control system of two-seater aircraft corresponding to CS-23 Level 2. First load calculations of each control surface are performed using the proses described in previous CS-23 regulation. This load is calculated trought the steering mechanism to control elements in cockpit. The resulting forces on the control elements are compared with the requi-rements in CS-23. Because the steering forces meets requirements is not necessary to propose changes in steering kinematics. However, there are further suggested ways of adjusting the control in case the external load would increase during further development of the airplane. At the end, the strength calculation of entire mechanism is preformed.

Tato diplomová práce se zabývá návrhem stavitelného stabilizátoru za účelem vyvažování letounu a zlepšení jeho letových výkonů. Cílem práce bylo navrhnout konstrukční řešení ovládání a zavěšení horizontálního stabilizátoru. Součástí je pevnostní výpočet kritických konstrukčních prvků a návrh letových zkoušek. V závěru jsou zhodnoceny výhody a nevýhody nového řešení a posouzení možnosti sériové výroby. Klíčová slova Ultralight, JA – 400, stabilizátor, stavitelný stabilizátor, vodorovné ocasní plochy, vyvážení. Abstract This thesis describes the design of adjustable stabilizer for the purpose of balancing the aircraft and improve its flight performance. The aim was to propose a design solution for control and hinge system of horizontal stabilizer. It includes the strength calculation of critical structural components and the design of flight tests. The conclusion evaluates the pros and cons of the new solutions and possibilities of mass production.

This thesis relates to a conceptual design of a light aircraft considering its easy manufacturability in non-professional workshop, for example at home. It is divided into three main parts. At the beginning there is mentioned a summary of existing light airplanes which determines the conceptual frame of the designed aircraft. The next part describes more detailed draft of different functional units, taking into consideration the constructional and manufacturing issues. The final part then contains basic equations to verify and define the most important characteristics of the designed aircraft.