Multi-walled carbon nanotubes (MWNTs) are a relatively new allotrope of carbon that have potentially useful properties that may improve polymer composites. The work of this thesis explores the interactions between MWNTs and functionalized MWNTs within epoxy matrix and the properties of the MWNT/epoxy composite. These interactions were characterized with an emphasis on finding how well the MWNT/epoxy composite flows and how conductive it is after curing.

The aim of this work was to assess the feasibility of 3-D inkjet printing of elastomers in latex form to create a novel material that would offer shielding against electromagnetic interference (EMI). To achieve this aim it was necessary to characterise and select suitable materials, carry out ink jetting trials, modify the materials accordingly to improve the printability and assess post jetting conditions including drying and curing behaviour. Particle size, surface tension, and viscosity measurements were made for a series of elastomer latex materials and carboxylated styrene butadiene rubber (XSBR) latex was identified as the most suitable. Latex ink optimisation included dilution with water and the addition of a humectant, triethylene glycol monomethyl ether (TGME), which delayed drying and reduced nozzle blocking. The surface energy was measured for arrange of potential substrates and PET was identified as the most suitable, due to its relatively high surface energy which allowed for an ideal level of wetting and spreading. Analysis of the cross-sectional profiles of the printed samples by white light interferometry showed that drying during printing was an important issue for the latex ink. Ink jetting of a composite material with control of filler distribution was shown to be feasible when ten layers of conductive carbon black ink were deposited alternately between ten layers of XSBR ink. Printing was successfully carried out with a latex combined with a resorcinol resin which was subsequently cured, indicating that it should be possible to 3D print a thermoset elastomer in this way. Conductive carbon black was printed in various patterns onto PET sheet and the dielectric properties measured. Results indicated that at very low carbon contents, the printed patterns could provide EMI shielding. The research has shown that it is feasible to create a cured 3D elastomeric object containing filler with a controlled distribution that is capable of providing EMI shielding.

New textile materials are constantly being brought into the automotive field, and automobile design is a leader in innovative and spectacular developments where smart textile materials are used. The main elements of the current project are textile material research, automotive research, design and development of two upholstery concepts for automotives using smart textiles. The added values are RFI/EMI (Radio Frequency Interference / Electro Magnetic Interference) shielding qualities, light emitting, light reflective and antistatic qualities. Values in the smart-textile area are obtained through choice of material and textile techniques. Transportation textiles are considered high performance technical fabrics, but they must also meet the aesthetic demands of the market. In the current project the design is inspired by Japanese architectural thinking and strives to relate to outdoor environment to reduce the border between indoor and outdoor environment. The inspiration source is water surfaces. The colour setting is also inspired by water surfaces. Material selection is based on the chosen added values, material qualities, appearance and availability. The result of the work is two different upholstery concepts visualizing qualities of smart materials and requests the automotive field. Sprinkle is an upholstery with light emitting, light reflective and antistatic values. The materials used are monofilament, polyester and electroluminescent wires. Wave is an upholstery design with antistatic, light reflective and RFI/Emi shielding qualities. The materials used are stainless steel yarn, rubco and monofilament. / <p>Program: Konstnärligt masterprogram i mode- och textildesign</p><p>Uppsatsnivå: D</p>

This thesis introduces, for the first time, a novel 4-bit, metal-oxide-metal (MOM) digital capacitor switching array (MOMDCSA) which has been implemented into a wideband CMOS voltage controlled oscillator (VCO) for 5 GHz WiMAX/WLAN applications. The proposed MOMDCSA is added both in series and parallel to nMOS varactors. For further gain linearity, a wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to four nMOS varactor pairs, each of which is biased at a different voltage. Thus, VCO tuning gain reduces and optimal phase noise variation is obtained across a wide range of frequencies. Based on this premise, a wideband VCO is achieved with low phase noise variation of less than 4.7 dBc/Hz. The proposed VCO has been designed using UMC 130 nm CMOS technology. It operates from 3.45 GHz to 6.23 GHz, with a phase noise of -133.80 dBc/Hz at a 1 MHz offset, a figure of merit (FoM) of -203.5 dBc/Hz. A novel microstrip low-phase noise oscillator is based on a left-handed (LH) metamaterial bandpass filter which is embedded in the feedback loop of the oscillator. The oscillator is designed at a complex quality factor Qsc peak frequency, to achieve excellent phase noise performance. At a centre frequency of 2.05 GHz, the reported oscillator demonstrates, experimentally, a phase noise of -126.7 dBc/Hz at a 100 kHz frequency offset and a FoM of -207.2 dBc/Hz at a 1 MHz frequency offset. The increasing demands have been placed on the electromagnetic compatibility performance of VCO devices is crucial. Therefore, this thesis extends the potential of highly flexible and conductive graphene laminate to the application of electromagnetic interference (EMI) shielding. Graphene nanoflake-based conductive ink is printed on paper, and then it is compressed to form graphene laminate with a conductivity of 0.43×105 S/m. Shielding effectiveness is experimentally measured at above 32 dB as being between 12GHz and 18GHz, even though the thickness of the graphene laminate is only 7.7µm. This result demonstrates that graphene has great potential for offering lightweight, low-cost, flexible and environmentally friendly shielding materials which can be extended to offering required shielding from electromagnetic interference (EMI), not only for VCO phase noise optimisation, but also for sensitive electronic devices.

Aktuální postup testování je příliš zdlouhavý a nepřesný, zároveň není měření některých vlastností motoru vůbec možné. Hlavním úkolem zařízení je zrychlení a zjednodušení procesu testování spolu s možností otestovat všechny vlastnosti motorů. Realizace zařízení začala definováním požadavků zákazníka, dalším krokem byla analýza daných požadavků a návrh zařízení. Následovala výroba a programovaní firmwaru spolu se softwarem. Výsledkem práce je funkční přístroj schopný automatického testování sedmi základních typů motorů, měření všech požadovaných funkcí spolu s novou možností měření počtu tiků enkodéru, periody FG signálu z řídící elektroniky BLDC motorů a napěťové úrovně těchto signálů. Dalšími rozšířeními jsou možnost uložení výsledků z uskutečněných testů pro možné budoucí využití a možnost vizualizace proudu motorem. Uživatel je tedy schopný otestovat velké množství motorů v kratším časovém úseku a zároveň se o testovaných motorech dozvědět mnohem více informací než doposud.

In recent years, increased use of electronic devices and wireless operations resulted in unavoidable electromagnetic (EM) pollution which has a significant impact on civil and military sectors. Considering the foremost requirement, huge efforts were invested in the development of electromagnetic interference (EMI) shielding materials. In this context, metals are usually preferred but design complexities like high density and susceptibility towards corrosion are limiting factors; additionally, the reflection of microwaves from the surface fails to serve as EM absorbers. The concern here is to minimize the reflection of the high frequency electromagnetic wave from the surface and to enhance the microwave absorption in GHz frequencies. In this thesis, we have made an attempt to design EMI shielding materials with exceptional absorption ability derived from Polycarbonate (PC)/ Poly styrene-co-acrylonitrile (SAN) based polymer blends. Herein, unique co-continuous micro-phase separated blend structures with selective localization of microwave active nanoparticles in one of the phases were realized to be most effective for microwave attenuation over just dispersing it in one polymer matrix (i.e. PC and SAN composites). The synergistic attenuation of electric and magnetic field associated with EM radiation was achieved through incorporation of various magnetic nanoparticles, however, dispersion of magnetic nanoparticles was a challenging task. Therefore, in order to localize magnetic nanoparticles in PC phase of the blends and to enhance the dispersion state, various modification strategies have been designed. In summary, we have developed a library of engineered nanoparticles to achieve synergistic attenuation of EM radiation mostly through absorption. For instance, the PC/SAN blends containing MWNTs and rGO-Fe3O4 nanoparticles manifested in exceptional EMI shielding, well above required shielding effectiveness value for most of the commercial applications, essentially through absorption. Taken together, the finding suggests that immiscible blends containing MWNTs and the decoration of magnetic nanoparticles (rGO-Fe3O4) on the surface of reduced graphene oxide sheets can be utilized to engineer high-performance EMI shielding materials with exceptional absorption ability.