Particle concentration measurement and flow regime identification in multiphase pipe flow using a generalised dual-frequency inversion method

An acoustic particle concentration measurement method, originally developed for marine sediment, in which the backscattered energy received by emitter-receiver transducers in the megahertz range is used to construct concentration profiles in suspensions of solid particles in a carrier fluid is applied to suspensions of general engineering interest. Four particle species with range of densities and sizes are used. Concentration profiles in horizontal, turbulent pipe flow at a Reynolds number of 50,000 and three nominal volume fractions are presented for each particle species, using experimentally determined acoustic coefficients, in order to isolate the influence of particle size and density on transport and settling in solid-liquid multiphase flows. It is clear from the results that the method allows the degree of segregation in real suspensions and slurries to be measured, and has a range of potential applications in the nuclear and minerals processing industries, for example. Lastly, the limiting conditions of the method are explored through the concept of an acoustic penetration depth

Transit Photometry as an Exoplanet Discovery Method

Photometry with the transit method has arguably been the most successful exoplanet discovery method to date. A short overview about the rise of that method to its present status is given. The method's strength is the rich set of parameters that can be obtained from transiting planets, in particular in combination with radial velocity observations; the basic principles of these parameters are given. The method has however also drawbacks, which are the low probability that transits appear in randomly oriented planet systems, and the presence of astrophysical phenomena that may mimic transits and give rise to false detection positives. In the second part we outline the main factors that determine the design of transit surveys, such as the size of the survey sample, the temporal coverage, the detection precision, the sample brightness and the methods to extract transit events from observed light curves. Lastly, an overview over past, current and future transit surveys is given. For these surveys we indicate their basic instrument configuration and their planet catch, including the ranges of planet sizes and stellar magnitudes that were encountered. Current and future transit detection experiments concentrate primarily on bright or special targets, and we expect that the transit method remains a principal driver of exoplanet science, through new discoveries to be made and through the development of new generations of instruments.Comment: Review chapte

Asthma inflammatory phenotypes on four continents: most asthma is non-eosinophilic.

BACKGROUND: Most studies assessing pathophysiological heterogeneity in asthma have been conducted in high-income countries (HICs), with little known about the prevalence and characteristics of different asthma inflammatory phenotypes in low-and middle-income countries (LMICs). This study assessed sputum inflammatory phenotypes in five centres, in Brazil, Ecuador, Uganda, New Zealand (NZ) and the United Kingdom (UK). METHODS: We conducted a cross-sectional study of 998 asthmatics and 356 non-asthmatics in 2016-20. All centres studied children and adolescents (age range 8-20 years), except the UK centre which involved 26-27 year-olds. Information was collected using questionnaires, clinical characterization, blood and induced sputum. RESULTS: Of 623 asthmatics with sputum results, 39% (243) were classified as eosinophilic or mixed granulocytic, i.e. eosinophilic asthma (EA). Adjusted for age and sex, with NZ as baseline, the UK showed similar odds of EA (odds ratio 1.04, 95% confidence interval 0.37-2.94) with lower odds in the LMICs: Brazil (0.73, 0.42-1.27), Ecuador (0.40, 0.24-0.66) and Uganda (0.62, 0.37-1.04). Despite the low prevalence of neutrophilic asthma in most centres, sputum neutrophilia was increased in asthmatics and non-asthmatics in Uganda. CONCLUSIONS: This is the first time that sputum induction has been used to compare asthma inflammatory phenotypes in HICs and LMICs. Most cases were non-eosinophilic, including in settings where corticosteroid use was low. A lower prevalence of EA was observed in the LMICs than in the HICs. This has major implications for asthma prevention and management, and suggests that novel prevention strategies and therapies specifically targeting non-eosinophilic asthma are required globally

Active vibration suppression with disturbance force estimation

Vibration is a basic phenomenon that has attached control engineering’s attention for many decades. Vibration rejection in control systems is implemented with passive, semi active and active vibration suppression systems. These methods commonly use multiple redundant sensors. Multiple sensor usage and complex control has implemented the cost of operation and complexity. Minimal sensor usage to provide vibration suppression within the commonly used acceleration or deflection observation could be used to reduce the complexity and the cost of the system. This dissertation proposes a novel methods which uses either the acceleration or motor deflection measurement based disturbance force observe for vibration observations and to suppress the vibrations with active vibration suppression. The proposed system is capable of estimating the disturbances and compensate disturbance using the only a acceleration or suppression deflection sensory data. Proposed system still could work as a traditional vibration suppression system in case of a failure to active system. Active for to be injected is calculated based on the disturbance forces acting on the sprung mass. A novel method is proposed for spring and damper parameter measurements with electromagnetic actuators which enhance the overall system performance. A Quarter car model is used to illustrate the adaptability, robustness, and the vibration suppression capabilities of the system. Performance of the active vibration suppressor and disturbance observer is measured using system simulations and practical results. Simulation and practical system responses provide evidence of robust vibration suppression capabilities of the proposed method under different conditions

Simulation of brake by wire system with dynamic force control

By wire technology is recently developed to improve the reliability, safety, and performance of vehicular drive technology. Brake system is the most important control system for vehicle safety. By wire technology development has encouraged the development of brake by wire systems to reduce traditional mechanical and hydraulic systems usage in automobiles. This paper proposes a novel brake by wire controller that uses a reaction force based bilateral motor controlling method. The proposed system uses two linear actuators with disturbance observer and reaction force observers to provide pedal force amplification and pedal retraction capabilities. The system includes a force controller to provide pedal feel to drivers. Electro mechanical brake position control is used to provide the brake force. The proposed system is simulated for different conditions to measure the performance and robustness. The simulation results provide evidence for robustness, force amplification, and pedal and brake retraction capabilities of the system

Simulation of active vibration suppression using internal motor sensing

Suppression of unnecessary vibration is an important aspect in control system design. Passive, semi active, and active suspension systems are used in vehicles to suppress vibrations and theoretically active suspension systems provide superior performance than the prior two types. This paper proposes a novel method to suppress vibrations using internal motor sensing method. The proposed active vibration suppression system uses a reaction force observer to measure and suppress vibrations acting on the system without using environmental sensors. The motor forcer acceleration and a current sensor measurements are used by the reaction force observer to measure the vibration forces in the system. The proposed system performed system performance, robustness, and applicability is evaluated using quarter car suspension system model. The proposed system is simulated for different conditions to measure the system vibration suppression capabilities. The simulation results provide evidence of robust vibration suppression capabilities and applicability of the controller for real world applications

Will climate change the future of homeland security?

Drought, melting Arctic ice, ocean acidification, and sea-level rise are all subsectors of climate change. I have identified these as slow-onset disasters. The purpose of this thesis is to determine whether slow-onset disasters are adequately addressed in the homeland security discipline. Risk assessments were performed to determine the level of risk these types of disasters pose to homeland security. The critical infrastructure lifeline sectors—Energy, Communications, Transportation Systems, and Water and Wastewater Systems—were chosen for these assessments because of their identified criticality to national security. The assessments reveal slow-onset disasters pose varying degrees of risk to these sectors. Policy analyses were conducted on the components of the nation's coordinated approach to homeland security. These reveal the homeland security discipline does not adequately address slow-onset disasters because of internal contradictions. The contradictions are the result of two of the frameworks used in the development of homeland security policies—continuity heuristic and probabilistic thinking. These frameworks lead disaster-consequence planners to consider the probability and magnitude of a disaster based on a retro-focused approach. Based upon my findings, I recommend that possibilistic reasoning (anticipating the worst that could happen), coupled with a future-focused approach, be used to develop homeland security policies that will fully address the emerging threats posed by slow-onset disasters.http://archive.org/details/willclimatechang1094550505Response and Recovery Bureau Chief New Mexico Department of Homeland Security and Emergency ManagementApproved for public release; distribution is unlimited