Adhesive wear occurs when small surfaces of the cutting tool due to friction are micro-welded to the chips and removed from the tool surface. A hypothesis as to whywelding occurs is that an electric potential field arises which initiates a chemical reaction and then welding of the work material and the tool takes place in the cuttingzone. The electric potential field results in a fluttering magnetic field, which in turngenerates electromagnetic issues. The waves should be around and above 1 MHz.The aim of this work is thus to investigate the presence of electromagnetic wavesfrom the cutting zone. The purpose is to compare sound and electromagnetic wavesduring the adhesive process. Previous research shows that the adhesive mechanism is a transient vibration thatmanifests itself as a cluster of waves with a stochastic duration, including a feedbacksystem restricted by the plastic deformation within the chip. Furthermore, the cutting speed is the most important cutting parameter in tool wear and the main wearmechanism at cutting speeds around 200 m/min is the adhesive wear. Several studies showed the emission of electromagnetic waves during plastic deformation ofmetals during tensile test. Frequency ranges for radiations are between 1 and 1000MHz. To investigate the hypothesis, axial turning was performed with a cutting speed190–200 (m/min) and one steel grade, SS2541 was used as a work material. Thedepth of cut and feed were set to 1 mm and 0,196 mm/rev. Detection and measurement of electromagnetic waves was performed with a spectrum analyzerMT8221B with four different signal receivers. A reference measurement was madewhen the turning machine was on without the workpiece being machined and then ameasurement was made during the turning process. The results of measurementsshowed a source of electromagnetic radiation within the frequency range 0–5 MHz.This result was achieved with copper plate as an antenna. To find out how signalsfrom acoustic emission and electromagnetic waves develop during the adhesive wearprocess, sound measurements were performed with microphones during the turningprocess. Results of sound measurement showed that the frequency at which adhesivewear occurs decreases and the amplitude increases as the insert wears. To be able toanalyze how electromagnetic radiation develops with the wear process, measurements must be performed in a shielded space from ambient disturbances, as in aworkshop there are many sources of noise that can affect the accuracy of the measurement. An antenna can be designed so that the measurement can take place asclose to the cutting zone as possible.

Radar technology is widely used in today´s society, whether it is the localisation and identification of aircraft in air traffic control systems, ships in harbour management systems, or the weather forecast presented on the news. In military applications, such as in fighter jets or missile lock-on systems, the speed at which the radar processes incoming data is essential to ensure a successful outcome. These applications need more powerful execution platforms, such as Application-Specific Integrated Circuits (ASICs) or Field-Programmable Gate Array (FPGAs) to run at the required speed. Radar technology manufacturers face both high development costs and long development cycles when designing, redesigning and developing these powerful execution platforms. A solution to these problems could be to design and develop the system in software before implementing it on the specialised ASIC and FPGA ships. As a step toward creating a software-based processing chain for radar systems, this thesis amide to investigate whether General-Purpose Graphical Processing Units (GPUs) could be used to develop and run beamforming applications in real-time at a sample rate of 100 MHz. To achieve this goal, the Bartlett and MVDR Beamforming algorithms were analysed and implemented in the Computer Unified Device Architecture (CUDA) programming framework on an NVIDIA GeForce RTX 2080 super GPU. The algorithms´ parallelisable elements were considered before implementation, and then implemented to fit with the CUDA programming model. In the end, both beamformers´ primary acceleration methods is using the cuBLAS library for linear algebra operations. The results of this study show that beamforming in real-time is not possible on a GPU when processing a signal sampled at 100 MHz. However, the GPU used just passed its third anniversary since release, and NVIDIA has released subsequent generations of GPUs with significant (>100%) performance increases. Future work on this area could include trying the implementations on more recent GPUs or implementing other beamforming algorithms on GPUs. / Radarteknik används inom flera områden idag. Bland annat för lokalisering och identifiering av flygplan och fartyg i flyglednings- och hamnledningssystem, eller för att skapa väderprognosen som presenteras på nyheterna. För militära tillämpningar, till exempel i stridsflygplan eller missillåsningssystem, är behandlingshastigheten av inkommande data avgörande för att korrekt information ska visas. Dessa användningsområden kräver kraftfulla chip, såsom ASICs eller FPGAer, för att uppnå den exekveringshastighet, kompakthet och energieffektivitet som krävs. Såväl höga utvecklingskostnader som långa utvecklingscykler uppstår för radartillverkare när de designar och utvecklar dessa kraftfulla chip. En lösning på de långa cyklerna och höga kostnaderna kan vara att designa och utveckla systemet i mjukvara på en högre abstraktionsnivå innan det implementeras på de specialiserade ASIC- och FPGA-chipen. I ett steg mot att skapa en mjukvarubaserad signalbehandligsskedja gör radarsystem, syftar detta examensarbete till att undersöka om GPUer skulle kunna användas för att utveckla och exekvera beamformingapplikationer i realtid med en samplingsfrekvens på 100 MHz. För att uppnå detta mål analyserades och  implementerades beamformingalgoritmerna Bartlett och MVDR i CUDA på en NVIDIA GeForce RTX 2080 Super GPU. De element av algoritmerna som går att parallellisera undersöktes, följt av implementation i CUDAs programmeringsmodell. Den primära accelerationsmetoden för båda beamformingalgoritmerna är att använda cuBLAS-biblioteket för linjär algebraoperationer. Resultaten av denna studie visa att beamforming i realtid inte är möjligt på en GPU vid behandling av en signal samplad i 100 MHz. Den GPU som användes har nyligen passerat sin tredje årsdag sedan lansering, och NVIDA har släppt efterföljande GPU-generationer med avsevärda (>100%) prestandaökningar- I framtida arbeten på området föreslås att testa implementationerna på nyare GPUer, implementera beamformers i t.ex. OpenGL, implementera andra beamformingalgoritmer i CUDA.

Electron holes are positively charged nonlinear structures in which trapped electrons are supported by a positive electrostatic potential. These structure are regularly observed in space and laboratory plasmas by means of diverging bipolar electric field signatures. Recent observations and simulations have shown that fast moving electron holes can generate electromagnetic whistler waves via Čerenkov emission. The fast moving positive charge correspond to localised currents which can potentially excite waves. The aim of the project is to study both theoretically and numerically the properties leading to the Čerenkov emission of whistler waves by three-dimensional electron holes. In addition, efforts are dedicated to the derivation of a model providing the properties of emitted whistlers. The model is compared with the observational features of electromagnetic whistler waves generated by electron holes.