This thesis deals with really small cyclone separators which could be used for a flue gas purification. The search section discusses particle formation in combustion, their characteristics, any other flue gas cleaning options and last but not least, a cyclone separator where is the effort to understand all the influences that contribute to a cyclone’s resulting separability. The Experimental section analyses a calculation of the cyclone and theoretical separability, a verification of this separability using a cyclone created by a 3D printer. On the one hand, the verification was made by gravimetric analysis which is intended for a bigger particles, on the second hand, it was made using the PALAS which is aimed at particles in µm. There is also a comparison of theoretical and measured values in this section.

Landfalling tropical cyclone (TC) induced precipitation poses a great risk to the rising coastal population globally. However, the impacts of tropical cyclone precipitation (TCP) are still difficult to predict due to rapid structural changes during landfall. This study applies a shape metric methodology to quantify the spatiotemporal evolution of TCP in the North Indian (NI), Western Pacific (WP), and North Atlantic (NA) basins. The International Best Track Archive for Climate Stewardship (IBTrACS) data and the Global Precipitation Mission (GPM)'s advanced Integrated Multisatellite Retrievals for GPM (IMERG) dataset is employed to study the 2014-2020 landfalling TCP at three analysis times: pre-landfall, landfall, and post-landfall. We examine three thresholds (2, 5, and 10 mm hr-1) and use six spatial metrics (area, closure, solidity, fragmentation, dispersion, and elongation) to quantify the shape of the precipitation pattern. To identify precipitation changes among the three analysis times and three basins, the Kruskal-Wallis test is applied. The three basins show important differences in size evolution. The greatest structural changes occur during post-landfall when the rainfall extent shrinks. The WP has the largest area of TCP and generates the highest maximum TCP of all basins. NA is the only basin where the precipitation area expands after landfall. NA also has the lowest closure for the three precipitation thresholds. NI precipitation has the lowest dispersion and maximum closure. Shape metrics such as closure and dispersion show a consistent inverse correlation. The maximum precipitation direction within the TCs is also examined in each basin. These results can inform guidelines that contribute to improved TCP forecasting and disaster mitigation strategies for vulnerable coastal populations globally. Future studies can apply shape metrics to the sub-basins in NI and WP to examine regional variability as there has been no such study in these basins. Future work can also investigate if the location of heavy rainfall within the TC structure affects flooding or other water hazards. / Master of Science / Landfalling tropical cyclones (TC) pose a significant threat to coastal populations worldwide, primarily due to the heavy rainfall. Predicting the rainfall during landfall is challenging as they undergo rapid changes. This study uses shape metrics to measure how this rainfall changes over time and space in three ocean basins: North Indian (NI), Western Pacific (WP), and North Atlantic (NA). The study uses a comprehensive collection of global TC best-track data i.e., International Best Track Archive for Climate Stewardship (IBTrACS). The rainfall measurement is derived from the satellite data i.e., the Global Precipitation Mission (GPM)'s advanced Integrated Multisatellite Retrievals for GPM (IMERG) to study landfalling rainfall between 2014 to 2020. Six spatial metrics (area, closure, solidity, fragmentation, dispersion, and elongation) were applied to quantify the shape and size of the precipitation pattern at three landfall times: pre-landfall, landfall, and post-landfall. The values of the shape metrics are compared between the ocean basins and landfall times using a statistical test. The results show that the most significant changes occur after landfall when the rainfall area decreases. WP has the largest area of rainfall and generates the highest maximum rainfall of all basins. NA is the only basin where the rainfall area expands after landfall. Shape metrics such as closure and dispersion share a consistent negative relationship. The maximum precipitation direction within the TCs is also examined in each basin. These results can contribute to improved tropical cyclone rainfall forecasting and disaster mitigation strategies for vulnerable coastal populations globally. Future studies can apply shape metrics to the sub-basins in NI and WP to examine regional variability as there has been no such study in these basins.

A new processing technique, centrifugal flotation, has been developed in recent research projects to overcome the large residence times and fine particle limitations of traditional flotation technologies. The major innovation in the area of centrifugal flotation is the Air Sparged Hydrocyclone (ASH), which has proven capabilities in achieving quality products at specific capacities greater than traditional flotation methods. However, the ASH technology ultimately suffers from sparger plugging problems. Therefore, three unique flotation cyclone designs were developed utilizing external sparging systems and control features to float fine coal. The objective of each design was to create a system that mimics the behavior of the ASH technology, while providing advantages in bubble generation and retention time requirements. The evaluation of the three designs provided evidence towards the development of an efficient centrifugal flotation technique. Evaluation of a flotation cyclone with an external Cavitation Tube yielded a single-stage product with an ash content of 4.41% and a 45% recovery rate in a retention time of 0.66 seconds. However, the system required 16 minutes to meet comparable flotation yields and recoveries. The third design achieved a multiple-stage product of 11.32% ash at a 55% recovery in 20 minutes. These two designs provided low yield, high grade products, but rejected a high percentage of hydrophobic particles and required high retention times to meet typical flotation standards. In addition, these designs suffered by requiring high frother concentrations and recovery could not be increased through increased aeration due to design limitations. / Master of Science

Hurricane Florence (2018) was unique due to its slow storm motion during landfall, causing convective rainbands to produce high amounts of precipitation along the coast of North Carolina. This study focuses on the relationship between precipitation asymmetries and atmospheric stability surrounding the tropical cyclone (TC) during the landfall period of a nearly-stationary TC. Previous research with idealized hurricane simulations suggests that atmospheric stability may vary surrounding a TC during landfall, with the atmosphere destabilizing offshore and stabilizing onshore. However, this finding has not been studied using a realistic approach. Due to Hurricane Florence's slow motion, the storm was situated at the land-ocean boundary for multiple days, providing an ideal opportunity to examine the role of atmospheric stability in modifying hurricane precipitation during landfall. This study uses the Advanced Research Weather Research and Forecasting (WRF-ARW) version 3.6.1 to produce high-resolution simulations to examine the variations in precipitation and atmospheric stability surrounding Hurricane Florence. Precipitation accumulation at different temporal scales was used to determine that asymmetries existed during the landfall period. Observed and model-simulated Convective Available Potential Energy (CAPE) were used to measure stability surrounding the TC. Simulated CAPE indicates that there was a significant difference between stability right- and left-of-track. In addition to a control simulation, two experimental simulations were conducted by modifying the land surface to vary the heat and moisture exchange coefficient (HS) and hold the surface roughness (Z0) constant. By isolating the HS to be more moist or dry, the altered low-level moisture was hypothesized to cause the precipitation and convection distributions to become more symmetrical or asymmetrical, respectively. The results from the experimental simulations showed that the altered land surface affects the relative humidity from the surface to 950 mb, which has an immediate impact on stability off-shore left-of-track. Overall, the precipitation and stability asymmetries were not significantly impacted by the altered near-surface moisture, indicating other physical factors contribute to the asymmetries. The results of this study provide insight into the role of atmospheric instability in generating asymmetrical precipitation distributions in landfalling TCs, which may be particularly important in slow-moving TCs like Hurricane Florence. / Master of Science / Landfalling tropical weather systems such as hurricanes can significantly impact coastal communities due to severe flooding and damaging winds. Hurricane Florence (2018) affected coastal and inland communities in North Carolina and South Carolina when the storm produced a significant amount of precipitation over the coastal region. During landfall, the center of Hurricane Florence moved slowly parallel to the coastline, which creates a suitable time frame to isolate and study the influence of landfall on precipitation asymmetries. Precipitation asymmetry occurs when more rainfall falls on one side of the hurricane; for example, heavier precipitation tends to occur on the right side of a hurricane during the landfall period. Hurricane rainbands that are responsible for producing heavy precipitation form in areas where there is higher moisture near the surface while lighter precipitation forms in areas where there is drier air near the surface. This study focuses on the relationship between land surface moisture and spatial variations of precipitation during the hurricane landfall period by studying observations and model simulations of Hurricane Florence. The model simulation of Hurricane Florence found that more precipitation fell on the right side of the storm, indicating that there was precipitation asymmetry. In order to understand how the precipitation asymmetries form, the model simulation of Hurricane Florence was modified to create two experiments. In the first experiment, the land surface was altered to have a moister land surface, which should cause the hurricane precipitation to be more symmetrical. In the second experiment, the land surface was altered to have a drier land surface, which should cause stronger precipitation asymmetry. However, the results did not match this expectation. Instead, both experiments simulated asymmetrical precipitation with more precipitation falling on the right side of each storm during the landfall period. These results suggest that the modified land surface moisture did not have a significant impact on the formation of precipitation asymmetries. Other factors are therefore suggested to have a more dominant influence on the development of precipitation. Overall, this work can support future studies by ruling out the impact of land surface moisture on a hurricane's precipitation formation during the landfall period.

Introduction The COSTIS system is a commercially available target station for the irradiation of solid targets. Up to 3 targets can be provided for irradiation by a slot system. In standard setup the target can be ejected via a pneumatically driven piston system. The target is then allowed to drop down into an open lead container, which can be closed remotely afterwards. The described procedure is well established and reliable. But the concept is limited to low dose targets and environments. The required entering of the cyclotron vault for manual pick up of the container at the cyclotron and the light 18 mm Pb lead shielding of the container itself cause exposure risk for the personnel after long term irradiations with highly activated cyclotron parts and target. The purpose of this work was the design of an alternative for the pickup and the transport of irradiated targets to minimize the radiation dosage of the personnel during manual handling of the COSTIS-lead container. Principle The new designed transport system still uses the software controlled target ejection function of the COSTIS/IBA-system. With ejection the target capsule is allowed to fall into a PTFE-container. To assure a safe target drop into the PTFE container, the gap between the target guiding plate and the PTFE container is smaller than d/2 of the target capsule. After target ejection the PTFE-container can be transferred remotely from target ejection position (1) to the loading station (2) with a target slide. The loading station allows the transfer of the PTFE container remotely into a lead container (60 mm Pb). Now the vault door is used as carrier of the Pb-container. For this purpose a proper fixture for the Pb-container is mounted at the front side of the vault door and via opening the vault door the container is safely transported out of the vault. Outside the container will be finally closed with a lid and transferred to a trolley for further handling. Due to positioning of the container at a certain altitude together with the deep positioning of the target coin inside of the container, the subsequent closing of the container does not cause significant dosage, a more complicated automatic closing system is not mandatory. After replacement of the lead container further transfers can be executed without entering the vault. For this purpose the exchanged Pb-container is placed at the loading station by closing the vault door and a new PTFE-container will be transferred remotely from a magazine onto the target slide, which again can be re-motely positioned at target ejection position. The magazine of PTFE-Containers holds two replacements in accordance with the maximal capacity of the target slot system of the COSTIS station. The remote system of the transport unit uses redundant feedback signals for a reliable and safe operation. Results and Conclusion The newly implemented transport system allows a significant reduction of the radiation dose during pickup and transport of the irradiated solid targets. No entering of the vault is needed after irradiation. The system is highly reliable due to its redundant and straightforward design (2-fold position switches and photoelectric barriers). Due to fixed attachment points in the vault and at the BTL the mobile unit can be easily removed or mounted. The system is maintenance free and all parts easy accessible. For further handling of the targets lead containers were design to fit in the transfer locks of hot cells. The transfer can be carried out directly from the trolley. Container lid and PTFE container are suited for manipulator handling in hot cells.

Introduction A widely distributed commercially available target station for the irradiation of solid targets is the COSTIS system. The system is specified for beams up to 500 W and is equipped with a front side He-cooling and water cooling on the back side. The target itself has a coin shape with a diameter of 24 mm and thickness of 2 mm. This recommends the system for irradiation of thin targets like foils but it is also useable for irradiation of metal and oxide powders. However the irradiation of powders and granulates is limited due to the dimension of the target capsule. A setup of a capped closed target is hardly achievable. The purpose of this work was the modification of the COSTIS target station for the use of thicker target capsules. This shall enable the more easy and safe handling and irradiation of powdery targets and the use of lockable target capsules. Material and Methods The adaption of the COSTIS system for wider targets is easy and fast achievable by the ex-change of the target guiding plate together with the four distance bolts and their bearings. The effort of the replacement of the standard with the modified parts is comparable with COSTIS maintenance including exchange of the window foil and the O-rings. For the target capsule itself different designs were developed and tested. Now various target capsules are available, depending on required energy, handling needs and properties of the target material. Different locking systems can be used, from “click” capsules to screwable systems. Additionally the tightness of the target capsule can be achieved by placement of on O-ring between the lid and capsule body. Results and Conclusion The wider target body allows the capping of the target material. This enables a wide range of applications. One aspect is the nanoparticle research, where radiolabelling is an excellent tool for in situ online investigations. The chosen design of the target capsule allowed the direct activation of TiO2 nanoparticles. Via the nuclear reaction 48Ti(p,n)48V radiolabelled [48V]TiO2 nanoparticles can be obtained. Another example is the use of recoil effects for radiolabelling of nanoparticles. In this case the kinetic energy of the product of the nuclear reaction 7Li(p,n)7Be is used to implant a radioactive tracer in different nanomaterials like Ag0 – nanoparticles and MWCNT (multi wall carbon nano tubes). In general the irradiation of powders and granulates benefits from the modified design that allows the more flexible adaption to experimental needs.

Made available in DSpace on 2014-10-09T12:27:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:13Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Introduction Krypton-81m is a radioactive gas with a half-life of 13 s, and found to be useful in many applications in nuclear medicine, particularly for lung perfusion studies and ventilations. Due to high demands for 81mKr, we have developed an automated Krypton system to be installed in one of the Cyclotron’s beamlines at King Faisal Specialist Hospital and Research Centre (KFSH&RC) and to deliver large activity of the radioactive gas. Material and Methods The effective cross section of producing 81Rb is between 15 and 30 MeV [1]. Therefore, range and stopping power of the effective cross section were calculated with respect to gas density of 0.0185 g/cm3. This value is equivalent to gas density at 5.0 bars at room temperature. SRIM calculations resulted in a range of 589 mm. However, due to limitation in fabricating such long target chamber, the target length is chosen to be 250 mm. Attached to the end of target body is a special water circulating flange ‘back-pool’, its purpose is to absorb the rest of the energy and protons Bragg peak. The target body is made of Aluminum with the inner part being electroplated with nickel. The target body is of conical shape. The target body is electrically isolated from other parts to allow accurate beam current reading. Full access to the target loading/unloading steps is made through touch screen technology (FIG. 2) for user access. Additionally, the target control system is designed to be protected through chain of interlock steps. The production cycle of 81Rb is explained as follow. Target is evacuated to approximately 10−3 mbar before being filled with natKr at pressure of 5 bars. At the end of bombardment, recovery of natKr is done via cryogenic vessel. Finally, the radioactivity is washed with KCl and pushed to Hotcells through the nitrogen gas for chemistry processing. Irradiation time was approximately 30 min. Results and Conclusion Experimental results clearly showed a fairly good activity of 81mKr as shown in TABLE 1. In all experiments, the radionuclidic purity of 81mKr was above 99.59%. 79mKr and 79Kr were also measured with a percentage of, respectively, 0.34 and 0.07 %. Special attention has to be drawn to last experiment where the yield significantly in-creased, due to the period where the KCl left inside the target (10 min) before pushing the solution to the Hotcells

Introduction Nitrogen [13N] NH3 is a liquid radioisotope, produced by medical cyclotrons for nuclear medicine application and widely applied for evaluation of myocardial perfusion in clinical assessments [1,2]. Owing to its short half-life (10 minutes), the unloading procedure of the radio-active solution of [13N]NH3 from the target is crucial in saving the activity produced for patient. Therefore, an efficient technique in un-loading the radioactive solution from the target body was developed using COMSOL Multiphysics. The new design of the target with improved unloading technique resulted in 30% increase of the available 13N activity. In our experiments, 13N was produced by the 16O(p,α)13N reaction. The energy of proton beam was 16.5 MeV. Material and Methods A 2D model was developed using COMSOL Multiphysics to simulate the inner geometry of [13N] Ammonia target. In the 2D model, water and aluminum were used as materials for the inner body and outer boundary (walls), respectively. The physical equations used to solve the problem of allocating proper place for the loading/unloading opening is turbulent, k-ε Module being extracted from fluid flow module. FIGURE 1 shows the result of simulating water flow on the target water channels. The entrance of the pushing solution (for unloading) was designed to create a turbulent flow inside the target body and, hence, to collect most of the activity inside the target. FIGURE 2 shows the setup for 13N production. A peristaltic pump is used to push the solution after irradiation to the hotcell at 6 ml/min flowrate. The distance from the target to the hotcell is approximately 30 meters. Results and Conclusion FIGURE 3 presents activity produced in milicurie (mCi) for several patient runs. The activity obtained in some experiments reached up to 330 mCi when we irradiated the target with 25 μA for 15 min. This was satisfactory for delivery to the patient at the nuclear medicine department. Moreover, purity of [13N] purity was above 95 % what meets the standard regulation for administration to a patient.

Approved for public release, distribution is unlimited / Consensus methods require that the techniques have no bias and have skill. The accuracy of six statistical and dynamical model tropical cyclone intensity guidance techniques was examined for western North Pacific tropical cyclones during the 2003 and 2004 seasons using the climatology and persistence technique called ST5D as a measure of skill. A framework of three phases: (i) initial intensification; (ii) maximum intensity with possible decay/reintensification cycles; and (iii) decay was used to examine the skill. During both the formation and intensification stages, only about 60% of the 24-36 h forecasts were within +/- 10 kt, and the predominant tendency was to under-forecast the intensity. None of the guidance techniques predicted rapid intensification well. All of the techniques tended to under-forecast maximum intensity and miss decay/reintensification cycles. A few of the techniques provided useful guidance on the magnitude of the decay, although the timing of the decay was often missed. Whereas about 60-70% of the 12-h to 72-h forecasts by the various techniques during the decay phase were within +/- 10 kt, the strong bias was to not decay the cyclone rapidly enough. In general the techniques predict too narrow a range of intensity changes for both intensification and decay. / Captain, United States Air Force