This report covers the product development process of a C-profile forming a box beam for use in storage systems. The company Brännehylte Lagersystem AB is in need of a new box beam that in pair can handle a maximum load of 4000 kg (four pallets x 1000 kg). At present the company has only one beam capable of a maximum load of 4x800 kg and wants to expand its product range and develop as a company and compete with others in the storage systems market. The first step began with acquiring information on the different beams and how they behave under stress. Then began a combination of brainstorming and brainwriting to generate a number of concepts of how a C-profile could possibly look like. After screening of the different concepts using Gut-feeling method three most appropriate concepts were left and were pitted against each other in a Pugh Matrix to get the best possible C-profile for further development. Calculations and tests were done on the selected concept with a combination of elementary cases and SolidWorks. For the beam to be approved it must meet the EU standard for storage racks. The calculated beam resulted in a working beam in theory, which in turn must be produced to confirm that the theory is true. Because a prototype must be produced in order to confirm the results, then the work cannot be proven in practical example and only be proven in theory.

In remote areas without conventional cellular service, satellite communication is often the only viable option. Handheld devices for use with satellite communication networks require a high transmit power to obtain a reliable signal. The need for a high transmit power makes it difficult for the device to meet specific absorption rate (SAR) restrictions. An adaptive beam forming technique for shaping radiation away from the user’s head is proposed. This technique uses a back-to-back patch antenna design with an impedance monitoring based system capable of adaptively controlling the pattern of the antenna. The adaptive antenna system was designed, simulated, fabricated, and measured. The system could detect a head phantom within 3 cm of the antenna. SAR levels were verified to be within safety restrictions at 3 cm through simulation. By turning off the patch facing the user’s head when the phone is transmitting, and the user’s head is within 3 cm, it was shown that SAR levels could be reduced to safe levels. / February 2017

<p>III-Nitride materials have recently become a promising candidate for superior applications over the current technologies. However, certain issues such as lack of native substrates, and high defect density have to be overcome for further development of III-Nitride technology. This work presents research on lattice engineering of III-Nitride materials, and the structural, optical, and electrical properties of its alloys, in order to approach the ideal material for various applications. We demonstrated the non-destructive and quantitative characterization of composition modulated nanostructure in InAlN thin films with X-ray diffraction. We found the development of the nanostructure depends on growth temperature, and the composition modulation has impacts on carrier recombination dynamics. We also showed that the controlled relaxation of a very thin AlN buffer (20 ~ 30 nm) or a graded composition InGaN buffer can significantly reduce the defect density of a subsequent epitaxial layer. Finally, we synthesized an InAlGaN thin films and a multi-quantum-well structure. Significant emission enhancement in the UVB range (280 – 320 nm) was observed compared to AlGaN thin films. The nature of the enhancement was investigated experimentally and numerically, suggesting carrier confinement in the In localization centers.</p> / Dissertation

There is growing interest in using additive manufacturing for various alloy systems and industrial applications. However, existing process development and part qualification techniques, both involve extensive experimentation-based procedures which are expensive and time-consuming. Recent developments in understanding the process control show promise toward the efforts to address these challenges. The current research uses the process mapping approach to achieve control of melt pool geometry and microstructure in different alloy systems, in addition to location specific control of microstructure in an additively manufactured part. Specifically, results demonstrate three levels of microstructure control, starting with the prior beta grain size control in Ti-6Al-4V, followed by cell (solidification structure) spacing control in AlSi10Mg, and ending with texture control in Inconel 718. Additionally, a prediction framework has been presented, that can be used to enable a preliminary understanding of melt pool geometry for different materials and process conditions with minimal experimentation. Overall, the work presented in this thesis has the potential to reduce the process development and part qualification time, enabling the wider adoption and use of additive manufacturing in industry.

The Belle II detector is designed to collect data from the high luminosity electron-positron (e$^+$e$^-$) collisions of the SuperKEKB collider. It will explore the flavour sector of particle physics through precision measurements. The backgrounds of particles induced by the electron and positron beams will be much higher than in any previous \epem collider. It is important that these backgrounds be well understood in order to ensure appropriate measures are taken to protect the Belle II detector and minimize the impact of the backgrounds. In February 2016 electron and positron beams were circulated through the two 3 km vacuum pipe rings without being brought into collision during `Phase I' of SuperKEKB commissioning. Beam backgrounds were measured using Belle II's commissioning detector, BEAST II. BEAST II is composed of several small subdetectors, including helium-3 thermal neutron detectors. The BEAST II thermal neutron detector system and results from its Phase I running are presented in this dissertation. The Phase I experiment studies beam-gas interactions, where beam particles collide with residual gas atoms in the beampipes, and beam-beam interactions, where beam particles interact with each other. Simulations of these two types of backgrounds were performed using the Strategic Accelerator Design (SAD) and GEometry And Tracking (GEANT4) software packages. A method to account for the composition of the gas in the beampipes was developed in order to correctly analyse the beam-gas component of the background. It was also determined that the thermal neutron rates in the data on the positron beam were 2.18$^{+0.44}_{-0.42}$ times higher than the simulation of beam-gas interactions and 2.15$^{+0.34}_{-0.33}$ times higher for beam-beam interactions. The data on the electron beam were 1.32$^{+0.56}_{-0.36}$ times higher for beam-gas interactions and 1.91$^{+0.54}_{-0.48}$ time higher for beam-beam interactions. The impact of these studies on Belle II is discussed. / Graduate / samdejong86@gmail.com

Content: Preface Selected publications Statistics (Publications and patents, Concluded scientific degrees; Appointments and honors; Invited conference contributions, colloquia, lectures and talks; Conferences, workshops, colloquia and seminars; Exchange of researchers; Projects) Doctoral training programme Experimental equipment User facilities and services Organization chart and personnel

Resonant ionization laser ion sources are applied worldwide to increase purity and intensity of rare isotopes at radioactive ion beam facilities. Especially for heavy elements the laser wavelengths required for efficient resonant laser ionization are not only element dependent, but also vary to small degrees from isotope to isotope. Since the first operation of an actinide target at ISAC-TRIUMF in 2008, the demand for neutron-rich isotopes far away from stability has steadily increased. Those isotopes often have very low production rates so that often only a few ions per second are released. In order to study isotope shifts and hyperfine structure of silver, actinium and astatine, in-source resonant ionization spectroscopy in combination with radioactive decay detection has been applied. Despite the Doppler limited resolution, it has the advantage that it is ultra-sensitive and the atomic spectrum for the nuclear ground and isomeric states can be investigated individually. An isobaric separation has been demonstrated for 115-119Ag, where the hyperfine structure of one state showed a splitting of 22 GHz to 38 GHz while for the other state only a single peak spectrum can be resolved. For astatine and actinium, the main interest is to measure and study the optical isotope shift, which is for the first excitation step for neutron-rich isotopes in the order of IS_FES≈±3.7GHz/u for both elements, as these observables give insight into nuclear moments and shape. In addition, also the isotope shift of the second excitation step for astatine has been measured to IS_SES,At≈-1.7GHz/u. Laser spectroscopy on astatine has mainly been performed on the neutron-deficient isotopes 199,205At due to high count rates and low isobaric contamination. With the results obtained it is possible to extrapolate the required wavelength for ionizing and delivering the isotopes 221-225At which are of interest to e.g. electric dipole moment studies. / October 2017

Approved for public release; distribution is unlimited / A three dimensional analysis of the intensity distribution of backward optical transition radiation has been performed. The effects of variations in electron energy and beam divergence and on material properties such as dielectric permittivities and the resultant coherence length upon the angular distribution and polarization of optical transition radiation has been investigated. A surprising observation important to the use of optical transition radiation as a diagnostic tool for high energy electron beams is the behavior of the perpendicular component of the intensity. In contrast to low energies where the parallel component dominates, at electron energies above 200 MeV, the perpendicular component dominates. This requires the use of a polarization filter to diagnose particle beam properties at high energies. / http://archive.org/details/threedimensional00long / Lieutenant, United States Navy

This research, is initiated to systematically study the microstructure of AISI 4340 steel prior to impact, after impact and after post-impact annealing to determine the effect of the pre-deformation microstructure on the nucleation and initiation of ASBs, and the mechanism of evolution of ASBs during impact. This study used state-of-the-art microstructural characterization techniques such as the FIB and STEM/HRTEM to reveal that initial microstructural inhomogeneity produces nucleation sites for the initiation of ASBs during impact. It was observed that double misfit interfaces and boundary layers, formed around precipitated carbides (interface between reinforcements and matrix), increased the volume fraction of dislocation sources within the pre-impact specimens. It is demonstrated that the intersection of an activated dislocation source with the direction of maximum shear (regions of stress concentrations) within the specimens during impact, is a necessary condition for the points of intersection to act as possible sites for the nucleation and initiation of ASB depending on the rate of dislocation generation, local strain and strain rate. In addition, the structure that evolves after strain localization starts out with elongation of the grains in the shear direction with the initiation of random and transverse dislocation boundaries along the elongated grains. The elongated grains break along the initiated dislocation boundaries as strain/strain rate increases resulting in the creation of smaller elongated-broken grains and nanograins. Boundary refinement of the broken grains occurring through grain rotation and adiabatic heating results in the evolution of refined grains, subgrains and nanograins. The presence of elongated grains, broken grains, refined grains, subgrains and nanograins within the evolved shear band structures demonstrate that the local deformation is dependent on the imposed local strain and strain rate and that these mechanisms occur concurrently during impact. The results obtained, which are specific to the behavior of BCC ferritic Pearlitic hardenable steels, lead to the conclusion that the evolution of ASBs is a simultaneous layering of microstructures initially driven by dislocations which produce the final structures observed in the shear bands at the end of passage of the stress wave. / February 2015

<p>GaAs1-xBix is a III-V semiconductor alloy which has generated much fundamental scientific interest. In addition, the alloy possesses numerous device-relevant beneficial characteristics. However, the synthesis of this material is very challenging and its properties are not well understood. The focus of this dissertation is to advance the understanding of its synthesis using molecular beam epitaxy (MBE) and, as a result, improve its key as-grown properties that are of great importance to device applications, such as increasing Bi concentration in the alloy and enhancing its optical emission efficiency.</p><p>In chapter 3, the discovery of a trade-off between the structural and optical characteristics of GaAs1-xBix , controlled by the degree to which the growth is kinetically-limited, is described. Chapter 4 discusses the exploitation of a growth method that utilizes the spatial distribution of MBE fluxes to facilitate numerous studies of the critical dependence of GaAs1-xBix characteristics on the V/III flux ratio. Chapter 5 describes the results of experiments utilizing vicinal substrates to modify both Bi incorporation and optical emission efficiency of synthesized GaAs1-xBix and enable new understanding of the Bi incorporation mechanism. Specifically, incorporation primarily at A steps, defined as the steps generated by misorienting the GaAs (001) substrate toward the (111)A surfaces, enhances Bi incorporation but reduces optical emission efficiency. Chapter 6 describes the identification of two new signatures in the Raman spectra of GaAs1-xBix that can be used to determine the Bi content and the hole concentration of nominally undoped GaAs1-xBix. Finally, in Chapter 7 the GaAs1-xBix growth using pulsed Ga fluxes is described. The use of pulsed-growth significantly modifies the incorporation of Bi and suggests it is a promising method for widening the GaAs1-xBix MBE growth window enabling improved synthesis control and materials properties.</p> / Dissertation