120 research outputs found
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices
The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transpot project-demonstration act system definition
The 1985 ACT airplane is the Final Active Controls Technology (ACT) Airplane with the addition of three-axis fly by wire. Thus it retains all the efficiency features of the full ACT system plus the weight and cost savings accruing from deletion of the mechanical control system. The control system implements the full IAAC spectrum of active controls except flutter-mode control, judged essentially nonbeneficial, and incorporates new control surfaces called flaperons to make the most of wing-load alleviation. This redundant electronic system is conservatively designed to preserve the extreme reliability required of crucial short-period pitch augmentation, which provides more than half of the fuel savings
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study, volume 1
An active controls technology (ACT) system architecture was selected based on current technology system elements and optimal control theory was evaluated for use in analyzing and synthesizing ACT multiple control laws. The system selected employs three redundant computers to implement all of the ACT functions, four redundant smaller computers to implement the crucial pitch-augmented stability function, and a separate maintenance and display computer. The reliability objective of probability of crucial function failure of less than 1 x 10 to the -9th power per flight of 1 hr can be met with current technology system components, if the software is assumed fault free and coverage approaching 1.0 can be provided. The optimal control theory approach to ACT control law synthesis yielded comparable control law performance much more systematically and directly than the classical s-domain approach. The ACT control law performance, although somewhat degraded by the inclusion of representative nonlinearities, remained quite effective. Certain high-frequency gust-load alleviation functions may require increased surface rate capability
Predicting QT prolongation in humans during early drug development using hERG inhibition and an anaesthetized guinea-pig model
Identification of IKr Kinetics and Drug Binding in Native Myocytes
Determining the effect of a compound on IKr is a standard screen for drug safety. Often the effect is described using a single IC50 value, which is unable to capture complex effects of a drug. Using verapamil as an example, we present a method for using recordings from native myocytes at several drug doses along with qualitative features of IKr from published studies of HERG current to estimate parameters in a mathematical model of the drug effect on IKr. IKr was recorded from canine left ventricular myocytes using ruptured patch techniques. A voltage command protocol was used to record tail currents at voltages from â70 to â20Â mV, following activating pulses over a wide range of voltages and pulse durations. Model equations were taken from a published IKr Markov model and the drug was modeled as binding to the open state. Parameters were estimated using a combined global and local optimization algorithm based on collected data with two additional constraints on IKrIâV relation and IKr inactivation. The method produced models that quantitatively reproduce both the control IKr kinetics and dose dependent changes in the current. In addition, the model exhibited use and rate dependence. The results suggest that: (1) the technique proposed here has the practical potential to develop data-driven models that quantitatively reproduce channel behavior in native myocytes; (2) the method can capture important drug effects that cannot be reproduced by the IC50 method. Although the method was developed for IKr, the same strategy can be applied to other ion channels, once appropriate channel-specific voltage protocols and qualitative features are identified
Understanding the influence of race/Ethnicity, gender, and class on inequalities in academic and non-academic outcomes among eighth-grade students: findings from an intersectionality approach
Socioeconomic, racial/ethnic, and gender inequalities in academic achievement have been widely reported in the US, but how these three axes of inequality intersect to determine academic and non-academic outcomes among school-aged children is not well understood. Using data from the US Early Childhood Longitudinal StudyâKindergarten (ECLS-K; N = 10,115), we apply an intersectionality approach to examine inequalities across eighth-grade outcomes at the intersection of six racial/ethnic and gender groups (Latino girls and boys, Black girls and boys, and White girls and boys) and four classes of socioeconomic advantage/disadvantage. Results of mixture models show large inequalities in socioemotional outcomes (internalizing behavior, locus of control, and self-concept) across classes of advantage/disadvantage. Within classes of advantage/disadvantage, racial/ethnic and gender inequalities are predominantly found in the most advantaged class, where Black boys and girls, and Latina girls, underperform White boys in academic assessments, but not in socioemotional outcomes. In these latter outcomes, Black boys and girls perform better than White boys. Latino boys show small differences as compared to White boys, mainly in science assessments. The contrasting outcomes between racial/ethnic and gender minorities in self-assessment and socioemotional outcomes, as compared to standardized assessments, highlight the detrimental effect that intersecting racial/ethnic and gender discrimination have in patterning academic outcomes that predict success in adult life. Interventions to eliminate achievement gaps cannot fully succeed as long as social stratification caused by gender and racial discrimination is not addressed
SoTL Lab: Undergraduate student-faculty collaborative research in teaching and learning in CSD
The University of Wisconsin-Eau Claire Communication Sciences and Disorders SoTL Lab was designed to provide hands-on research experiences to undergraduate students on a large scale. Student reflections on experiences within the SoTL Lab identify the value of collaboration, development of confidence, and exposure to the entire research process as key outcomes. These experiences foster development of research skills and may lead students to consider academic careers
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Minority ethnic students and science participation: a qualitative mapping of achievement, aspiration, interest and capital
In the UK, the âleaky pipelineâ metaphor has been used to describe the relationship between ethnicity and science participation. Fewer minority ethnic students continue with science in post-compulsory education, and little is known about the ways in which they participate and identify with science, particularly in the secondary school context. Drawing on an exploratory study of 46 interviews and 22 h of classroom observations with British students (aged 11â14) from Black Caribbean, Bangladeshi, Pakistani, Indian and Chinese ethnic backgrounds, this paper identified five âtypesâ of science participation among minority ethnic students. The five types of science participation emerged from an analysis of studentsâ science achievement, science aspiration, science interest and science capital. The characteristics of the five types are as follows: Science adverse students have no aspirations towards science and lacked interest, achievement and capital in science. Science intrinsic students have high science aspirations, interest and capital but low science attainment. Students who are science intermediate have some aspirations, interest and capital in science, with average science grades. Science extrinsic students achieve highly in science, have some science capital but lacked science aspirations and/or interest. Science prominent students are high science achievers with science aspirations, high levels of interest and capital in science. The findings highlight that minority ethnic students participate in science in diverse ways. Policy implications are suggested for each type as this paper provides empirical evidence to counter against public (and even some academic) discourses of minority ethnic students as a homogeneous group
The Relations and Role of Social Competencies and Belonging with Math and Science Interest and Efficacy for Adolescents in Informal STEM Programs
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