Research was performed to study the particle adhesion on the wafer surface after the chemical-mechanical polishing (CMP) process. The embedded particles can be abrasive particles from the slurry, debris from pad material, and particles of film being polished. Different methods of particle removal mechanism were investigated in order to find out the most effective technique. In post-CMP cleaning, surfactant was added in the solution. Results were compared with cleaning without surfactant and showed that cleaning was more effective with the combined interaction of the mechanical effort from the brush sweeping and the chemistry of the surfactant in the solution (i.e., tribochemical interaction). Numerical analysis was also performed to predict the particle removal rate with the addition of surfactants. The van der Waals forces present in the wafer-particle interface were calculated in order to find the energy required to remove the particle. Finally, the adhesion process was studied by modeling the van der Waals force as a function of separation distance between the particle and the surface. The successful adaptation of elasticity theory to nanoparticle-surface interaction brought insight into CMP cleaning mechanisms. The model tells us that it is not always the case that as the separation distance is decreased, the attraction force will be increased. The force value estimated can be used for slurry design and CMP process estimation.

Research was performed to study the particle adhesion on the wafer surface after the chemical-mechanical polishing (CMP) process. The embedded particles can be abrasive particles from the slurry, debris from pad material, and particles of film being polished. Different methods of particle removal mechanism were investigated in order to find out the most effective technique. In post-CMP cleaning, surfactant was added in the solution. Results were compared with cleaning without surfactant and showed that cleaning was more effective with the combined interaction of the mechanical effort from the brush sweeping and the chemistry of the surfactant in the solution (i.e., tribochemical interaction). Numerical analysis was also performed to predict the particle removal rate with the addition of surfactants. The van der Waals forces present in the wafer-particle interface were calculated in order to find the energy required to remove the particle. Finally, the adhesion process was studied by modeling the van der Waals force as a function of separation distance between the particle and the surface. The successful adaptation of elasticity theory to nanoparticle-surface interaction brought insight into CMP cleaning mechanisms. The model tells us that it is not always the case that as the separation distance is decreased, the attraction force will be increased. The force value estimated can be used for slurry design and CMP process estimation.

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / Spread Spectrum (SS) techniques are methods used to deliberately spread the spectrum of transmitted signals in communication systems. The increased bandwidth makes detection of these signals challenging for non-cooperative receivers. In this paper, we investigate detection of Frequency Hopping Spread Spectrum (FHSS) signals from compressive measurements. The theoretical and simulated performances of the proposed methods are compared to those of the conventional methods.

The ionosphere is the atmosphere layer characterized by its high concentration of ionized plasma. It has a great impact on radio communications with satellites, causing disturbances and disruptions. Therefore, it is important to understand and predict the ionosphere characteristics. The Sweeping Impedance Probe (SIP) is an instrument for characterizing the ionosphere used for many decades with great success. In this thesis, a new SIP architecture design is presented using the latest techniques and components available. The design is detailed and analyses have been performed to ensure the required performances. The new SIP will be flown in the Auroral Spatial Structures Probe (ASSP) sounding rocket mission in early 2015, and it is expected it will make the most accurate measurements to date. Lastly, the conclusions of this project are presented and future work is outlined for what will become the next generation of SIP instruments.

The development of algorithms for the automatic creation of finite element meshes composed entirely of hexahedra (all-hex) is an active area of research. All-hex meshes are desirable for their characteristic of high accuracy with a low node count. Sweeping is one of the most widely used algorithms for generating all-hex meshes. A limitation of sweeping, however, is that it can currently be applied only to prismatic or extruded geometry types. This thesis develops a method to combine sweeping with another algorithm known as "Grafting". Grafting adjusts the mesh on one volume to conform to a second volume. In this manner it is useful for meshing multi-axis geometry in that a single axis can be meshed with sweeping and then secondary axes can be grafted on. By creating an algorithm for automatically performing these processes, the base set of geometry that can be automatically meshed with these methods is greatly increased. This new algorithm is called Graft-Sweeping. With the combination of sweeping and Grafting, geometry that contains multiple source surfaces, multiple target surfaces, and multiple sweep axes can be meshed. The results of this algorithm on several example geometries are given showing the strengths and weaknesses of this technique. From the results it can be seen that the Graft-Sweep algorithm can produce a finite element mesh in about half the time of manual Grafting and sweeping operations with similar mesh quality. When compared to sweeping alone, Graft-Sweeping is several times faster but the quality is usually reduced. A second area of research for this thesis is to determine when Grafting can be used to enhance the meshing process. It is shown that the best results are obtained when Grafting is used on structured meshes and the mesh size is considerably smaller than the size of the feature that is being grafted.

Millimeter wave systems leverage beamforming to generate narrow, high-powered beams for overcoming the increased path loss in the millimeter wave spectrum. These beams are spa- tially confined, making millimeter wave links more resilient to eavesdropping and jamming attacks. However, the millimeter wave radios locate each other and establish communica- tion by exhaustively probing all possible angular directions, increasing their susceptibility to attacks. In this thesis, we showcase a secure beam management solution where we apply an adaptive beam management procedure that avoids probing the directions of potential attackers. We employ a reinforcement learning agent to control the probing and dynami- cally restrict sweeps to a subset of beams in the millimeter wave transmitter codebook to avoid the locations of potential attackers based on a proposed metric that quantifies the beam sweeping secrecy over a pre-defined area. We evaluate our proposed system through numerical simulations and an experimental real-life implementation on the CCI xG Testbed. / Master of Science / Millimeter wave systems leverage beamforming, a technique that's used to direct both trans- mission and reception of a signal to create narrow, high-powered beams that can overcome the signal deterioration that comes with millimeter wave spectrum. The spatially confined nature of these beams makes millimeter wave links resilient to eavesdropping and jamming attacks. However, the millimeter wave radios find each other and establish communication by searching every possible angular direction, which increases the potential for the millimeter wave radios to be attacked. In this thesis, we showcase a secure method of establishing this communication link that avoids looking in the direction of a potential attacker. We then employ an artificial intelligence capable of controlling this search by sweeping a subset of all possible directions in the millimeter wave transmitter codebook based on a proposed metric that quantifies the secrecy of communication. We evaluate our proposed system through numerical simulations and an experimental real-life implementation on the CCI xG Testbed.

Parameter selection is a critical task in scientific workflows in order to maintain the accuracy of the simulation in an environment where physical conditions change dynamically such as in the case of weather research and forecast simulations. Currently, Numerical Weather Prediction (NWP) is the premier method for weather prediction, which is used by the National Oceanic and Atmospheric Administration (NOAA). It takes the current observations from observed sites as the input for numeric computer models and then produces the final prediction. Considering the large number of simulation parameters, the size of the configuration search space becomes prohibitive for rapidly evaluating and identifying the parameter configuration that leads to most accurate prediction. In this thesis, we develop an Autonomic Workflow Performance Manager (AWPM) for Hurricane Integrated Modeling System (HIMS). AWPM is implemented on top of the Apache Storm and ZooKeeper to handle multiple real-time data streams for weather forecast. AWPM can automatically manage model initialization and execution workflow and achieve better performance and efficiency. In our experiments, AWPM achieves better performance and efficiency for the model initialization and execution processes, by utilizing automatic computing, distributed computing and component-based development. We reduced the timescale of the configuration search workflow by a factor of 10 by using 20 threads with the full search method, and a factor of 20 by with the roofline method when compared to serial workflow execution as it is typically performed by domain scientists.

A bench-scale, sweeping gas, flat-sheet Membrane Distillation (MD) unit was used to assess the importance of membrane architecture and operational variables to distillate production rate. Sweeping gas membrane distillation (SGMD) was simulated for various membrane characteristics (material, pore size, porosity and thickness), spacer dimensions and operating conditions (influent brine temperature, sweep gas flow rate and brine flow rate) based on coupled mass and energy balances. Model calibration was carried out using four membranes that differed in terms of material selection, effective pore size, thickness and porosity. Membrane tortuosity was the lone fitting parameter. Distillate fluxes and temperature profiles from experiments matched simulations over a wide range of operating conditions. Limitations to distillate production were then investigated via simulations, noting implications for MD design and operation. Under the majority of conditions investigated, membrane resistance to mass transport provided the primary limitation to water purification rate. The nominal or effective membrane pore size and the lumped parameter epsilon/delta tau (porosity divided by the product of membrane tortuosity and thickness) were primary determinants of membrane resistance to mass transport. Resistance to Knudsen diffusion dominated membrane resistance at pore diameters <0.3 mu m. At larger pore sizes, a combination of resistances to intra-pore molecular diffusion and convection across the gas-phase boundary layer determined mass transport resistance. Findings are restricted to the module design flow regimes considered in the modeling effort. Nevertheless, the value of performance simulation to membrane distillation design and operation is well illustrated.

Parameters governing separation control with sweeping jet actuators over a deflected flap are investigated experimentally on a generic "Multiple Flap Airfoil" (MFA). The model enables an extensive variation of geometric and aerodynamic parameters to aid the scaling of this novel flow control method to full-size applications.Sweeping jets exit from discrete, millimeter-scale nozzles distributed along the span and oscillate from side-to-side. The sweeping frequency is almost linearly dependent on the supplied flowrate per actuator. The measured thrust exerted by a row of actuators agrees well with vectored momentum calculations. Frequency and thrust measurements suggest that the jet velocity is limited to subsonic speeds and that any additional increase in flowrate causes internal choking of the flow.Neither the flowrate nor the momentum input is found to be a sole parameter governing the lift for varying distance between adjacent actuators. However, the product of the mass flow coefficient and the square root of the momentum coefficient collapses the lift onto a single curve regardless of the actuator spacing. Contrary to other actuation methods, separation control with sweeping jets does not exhibit any hysteresis with either momentum input or flap deflection. A comparison between sweeping and non-sweeping jets illustrates the superior control authority provided by sweeping jets. Surface flow visualization on the flap suggests the formation of counter-rotating pairs of streamwise vortices caused by the interaction of neighboring jets.The actuation intensity required to attach the flow increases with increasing downstream distance from the main element's trailing edge and increasing flap deflection. No obvious dependence of the ideal actuation location on actuator spacing, flap deflection, angle of attack, or actuation intensity is found within the tested range. Comparisons between experimental and numerical results reveal that the inviscid flow solution appears to be a suitable predictor for the effectively and efficiently obtainable lift of a given airfoil configuration. The flap size affects the achievable lift, the accompanying drag, and the required flap deflection and actuation intensity. By controlling separation, the range of achievable lift coefficients is doubled without significant penalty in drag even when considering a safety margin for the maximum applicable incidence.

Bakgrund: Hinnsvepning är en icke farmakologisk induktionsmetod som används i syfte att framkalla spontan förlossningsstart eller förbereda cervix för annan induktionsmetod. Svensk förening för obstetrik och gynekologi (SFOG) rekommenderar hinnsvepning i graviditetsvecka 41 för att minska överburenhet. Metoden är omstridd och dess effekt ifrågasatt. Syfte: Att belysa barnmorskors erfarenhet av och attityd till hinnsvepning. Metod: Enskilda halvstrukturerade intervjuer med tolv barnmorskor verksamma inom mödrahälsovården i södra Sverige genomfördes. Data analyserades genom kvalitativ innehållsanalys. Resultat: I resultatet framkom att barnmorskor saknar utbildning i hinnsvepning och att majoriteten lärt sig utföra detta genom sina kollegor den dag de ställts inför uppgiften. Det saknas tydliga riktlinjer vilket kan innebära att hinnsvepning utförs på olika indikationer, vid olika tidpunkter i graviditeten och med olika tillvägagångssätt. Attityden till hinnsvepning varierar mellan barnmorskor, där en del tror på metoden och andra är mer skeptiska till dess effekt. Slutsats: Utbildning och tydliga riktlinjer saknas. Kvinnans önskan om och tilltro till hinnsvepning ligger ofta till grund för interventionen. / Background: Sweeping of membranes is a non-pharmacological induction method used to initiate labor or to prepare cervix for induction with other methods. The Swedish Association for Obstetrics and Gynecology (SFOG) recommends that membranes are swept after 41 full weeks of pregnancy to reduce post-term pregnancies. The method is disputed, and the effect is questioned. Aim: To describe midwives experiences and attitudes to membrane sweeping. Method: Individual half structured interviews with twelve midwives active in maternal healthcare in southern Sweden were performed. Data was analyzed by qualitative content analysis. Results: In the result emerged that midwives lack educating about membrane sweeping and that the majority had learned how to perform the intervention by colleagues the day they were faced with the task. Because of unclear guidelines membrane sweeping can be performed on various indications, in different times in the pregnancy and with different approaches. The midwives attitude towards membrane sweeping varies, some have belief in the method while others are more skeptical. Conclusion: Education and clear guidelines are missing. The woman´s desire for and confidence in the method is often the basis for the intervention.