Optimal control of a distributed parameter system with applications to beam vibrations using piezoelectric actuators

This paper addresses the issue of the active vibration control of the transverse modes in a flexible elastic systems. The control is implemented by discrete sets of piezoelectric actuators that apply the optimal forces. The performance index is a time-dependent quadratic functional of state variables and their time derivatives, and control forces which are determined by minimizing the objective functional subject to a penalty term on the control functions. A combination of Galerkin and variational approaches are employed to determine the control forces in the time domain explicitly in terms of coupled amplitudes and velocities. The effectiveness of the proposed method is demonstrated by applying it to a physical problem controlled by piezoelectric patch actuators.     

Books Received

Abstract

This paper analyses the organizational, financial and technological incentives that service organizations used to motivate farmers to finance agricultural research and extension in Benin. Understanding the foundations and implications of these motivation systems is important for improving farmer financial participation in agricultural research and extension.

We studied three cases of farmer financial participation in the field of agricultural research and extension in Benin. We conducted semi-structured interviews with leaders of service organizations and farmers’ associations, local authorities and individual farmers. Our interviews focused on service delivery systems, mechanisms of farmers’ financial contribution, the functioning of farmers’ associations, and the appropriateness of services provided. We performed thematic and comparative analyses at the interfaces between (1) service providers and partner–farmer associations, (2) service providers and delivered services, and (3) farmers/farmers’ associations and services.

Incentives for farmer financial participation are the increasing participation strategy, the fulfillment of farmers’ needs and the local leadership valorization. The selection and combination of their variants determine the motivating capacity and orientation of service organizations. Conversely to the increasing participation strategy, an effective fulfillment of farmers’ needs and local leadership valorization can lead to sustainable motivation. As the fulfillment of farmers’ needs determines importantly the effectiveness and sustainability of farmers’ motivation, the strategies of farmer financial participation are likely to fail if there are no successful agricultural technological incentives.

In the current context of privatization of agricultural services in developing countries, this analytical framework is of interest for policy makers and development workers for identifying conditions of farmer financial participation and designing effective motivation strategies.     

Fifth Graders’ Learning About Simple Machines Through Engineering Design-Based Instruction Using LEGO™ Materials

This study is part of a 5-year National Science Foundation-funded project, Transforming Elementary Science Learning Through LEGO? Engineering Design. In this study, we report on the successes and challenges of implementing an engineering design-based and LEGO?-oriented unit in an urban classroom setting and we focus on the impact of the unit on students’ content understanding of simple machines. The LEGO? engineering-based simple machines module, which was developed for fifth graders by our research team, was implemented in an urban school in a large city in the Northeastern region of the USA. Thirty-three fifth grade students participated in the study, and they showed significant growth in content understanding. We measured students’ content knowledge by using identical paper tests and semistructured interviews before and after instruction. Our paired t test analysis results showed that students significantly improved their test and interview scores (t?=??3.62, p?<?0.001 for multiple-choice items and t?=??9.06, p?<?0.000 for the open-ended items in the test and t?=??12.11, p?<?0.000 for the items in interviews). We also identified several alternative conceptions that are held by students on simple machines.     

Popular pedagogy and the changing political landscape: a case study of a women's housing movement in South Africa

This paper sets out to explore the relationship between popular education and the changing South African political landscape through case study research of the Victoria Mxenge Housing Development Association. The research took place over an extended period of time from 1992–2003 and discusses how popular education was advocated by the South African Homeless People's Federation and its parent NGO (People's Dialogue); how it was implemented, how an increasing disjuncture between teaching and learning occurred, and how pedagogy was shaped by both political and personal factors. The paper discusses the interactions between social movements and NGOs and the limitations of social movements and popular education. It argues for a more nuanced conceptual understanding of learning in social movements within development contexts.     

Body Composition Relative to Motor Aptitude for Preadolescent Boys

Abstract

The data for 40 variables were obtained from 81 Purdue University faculty sons between 10 and 12 years of age inclusive. Among the 40 variables, 680 correlation coefficients were obtained. Factor analysis was used to identify the factors which could explain the items measuring body composition and motor aptitude. As a result, eight factors were isolated and given names. The factors underlying the 40 variables seemed to permit the following names: growth and maturity factor, “body fitness” factor, body balance on object factor, coordination of the lower extremities factor, general kinesthetic sense factor, general static balance factor, directionality factor, and laterality factor. Observing the factor loadings in Factor I, it may be concluded that the measurement of lean body weight by liquid scintillation counting technique is significant in the assessment of growth and maturity in preadolescent boys. Furthermore, in the assessment of “body fitness” pertaining to preadolescent boys, it is revealed that the percent lean body weight is the most important item as indicated by the value of factor loading presented in Factor II.     

Effect of Short Study Abroad Course on Student Openness to Diversity

ABSTRACT: An important contributing factor to students' willingness to work with diverse people is their "openness" to diversity. The objective of this study was to test the effect of a short (3-wk) study abroad course to China on the openness to diversity/ challenge of the 23 students participating in the China study abroad course. Students were given the "openness to diversity" survey at the beginning of the course and at the end of the course. Statistical analysis concerning the change in openness to diversity between pre-test and post-test was conducted using the Mann-Whitney non-parametric test ( P ≤ 0.05). A significant increase ( P = 0.007) in openness to diversity was observed as a result of the short study abroad course. The overall average change in openness to diversity found for this study (0.07) was consistent with that reported for semester-long study abroad groups (0.074). Together these findings imply that short study abroad courses may have a significant effect on students' openness to diversity and may be as effective as longer study abroad programs. Overall, any study abroad course presents an opportunity to increase students' openness to diversity.     

Elements of the First Column of Routh's Array

A simple explicit recursive formula for the elements of the first column of Routh's array is presented. The use of this formula will eliminate the need for constructing the whole array.     

Training efl/esl teachers for a peaceful Asia-Pacific region

In this experimental study which is based on qualitative and quantitative data collection from an experimental and a control group, it has been found that when some educational terms in English Language Teacher Training programs are strengthened in meaning through some adaptations to better convey the message, their effectiveness is increased. Therefore, it is suggested that foreign or second language teachers in the Asia-Pacific region should not teach the target language only for linguistic and communicative purposes but also to introduce characteristics of different cultures and to contribute to educating people who enjoy similarities, respect differences and value human rights.     

Amplification of SPPS150 and Salmonella typhi DNA with a high throughput oscillating flow polymerase chain reaction device

In this paper, a novel oscillating flow polymerase chain reaction (PCR) device was designed and fabricated to amplify SPPS150 and salmonella typhi. In this new design, the samples are shuttled (oscillating flow) inside a microfluidic chip to three different temperature zones required for DNA amplification. The amplification cycle time has markedly been reduced as the reagent volume used was only about 25% of that used in conventional PCRs. Bubble formation and adsorption issues commonly associated to chip based PCR were also eliminated. Based on the performance evaluated, it is demonstrated that this oscillating flow PCR has the advantages of both the stationary chamber and continuous flow PCR devices.