811 resultados para pacs: systems theory application in education


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The preparation of a steam-based hydrothermally stable transition alumina is reported. The gel was derived from a synthetic sol-gel route where Al-tri-sec-butoxide is hydrolysed in the presence of a non-ionic surfactant (EO20PO70EO20), HCl as the catalyst and water (H2O/Al = 6); the condensation was enhanced by treating the hydrolysed gel with tetrabutylammonium hydroxide (TBAOH), after which it was dried at 60 °C by solvent evaporation. The so-obtained mesophase was crystallized under argon at 1200 °C (1 h) producing a transition alumina containing δ/α, and possibly θ, alumina phases. Due to its surface acidity, the pyrolysis conditions transform the block copolymer into a cross-linked char structure that embeds the alumina crystallites. Calcination at 650 °C generates a fully porous material by burning the char; a residual carbon of 0.2 wt.% was found, attributed to the formation of surface (oxy)carbides. As a result, this route produces a transition alumina formed by nanoparticles of about 30 nm in size on average, having surface areas in the range of 59-76 m2 g-1 with well-defined mesopores centered at 14 nm. The material withstands steam at 900 °C with a relative surface area rate loss lower than those reported for δ-aluminas, the state-of-the-art MSU-X γ-alumina and other pure γ-aluminas. The hydrothermal stability was confirmed under relevant CH4 steam reforming conditions after adding Ni; a much lower surface area decay and higher CH4 conversion compared to a state-of-the-art MSU-X based Ni catalyst were observed. Two effects are important in explaining the properties of such an alumina: the char protects the particles against sintering, however, the dominant effect is provided by the TBAOH treatment that makes the mesophase more resistant to coarsening and sintering. This journal is © the Partner Organisations 2014.

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We conducted an experimental study with the aim of testing certain conditions under which engaging with cultural diversity increases creativity among schoolchildren. Results obtained from a sample of 149 Italian elementary schoolchildren revealed that engaging with cultural diversity, operationalized by asking Italian children to work with immigrant children on a cooperative task, led to an increase in creativity. Furthermore, we found that this effect was only present when a communal but not a divisional mindset (emphasizing group distinctions) was present. We discuss theoretical and practical implications of findings.

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The objective of the work is to develop a fuel delivery system for potable direct methanol fuel cell. Currently, one of the most fundamental limitations of direct methanol fuel cells is that the fuel supplied to the anode of the DMFC must be a very dilute aqueous methanol solution (usually 0.5∼1.5 M). If a DMFC is filled with a dilute aqueous methanol solution, the fuel cell operation time per refuel would be very short, which would considerably diminish the advantage of a DMFC over a conventional battery. To overcome this difficulty, a complex fuel delivery system based on the modern micro system technology was proposed by the author. The proposed fuel delivery system would include micro-pumps, a methanol sensor, and a control unit. The fuel delivery system adds considerable costs to the fuel cell system and consume considerable amount of electricity from the fuel cell, which in turn significantly reduces the net power output of the fuel cell. As a result, the DMFC would have tremendous difficulty to compete with the conventional battery technology in terms of costs and power output. ^ This work presents a novel passive fuel delivery system for direct methanol fuel cells. In this particular system, a methanol fuel and an aqueous methanol solution are stored separately in two containers and a wick is disposed between the two containers in a siphon fashion, with the container of the aqueous methanol solution communicating with the anode of the DMFC. Methanol is siphoned from the methanol container to the aqueous solution container in-situ when the methanol in the aqueous methanol solution is consumed during the operation of the fuel cell. Through a proper selection of the wick and the containers, the methanol concentration near the anode of the DMFC could be maintained within a preferable range. ^

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The purpose of this study was to investigate the relationship between school principals' self-reported spirituality and their transformational leadership behaviors. The relationship between spirituality and transactional leadership behaviors was also explored. The study used Bass and Avolio's (1984) Full Range Leadership Model as the theoretical framework conceptualizing transformational leadership. Data were collected using online surveys. Overall, six principals and sixty-nine teachers participated in the study. Principal surveys contained three parts: the Multifactor Leadership Questionnaire (MLQ Form-5X Short), the modified Spirituality Well-Being Scale (SWBS) and demographic information. Teacher surveys included two parts: the MLQ-5X and demographic information. The MLQ-5X was used to identify the degree of principals' transformational and transactional leadership behaviors. The modified SWBS (Existential Well Being) was used to determine principals' degree of spirituality. The correlation coefficients for the transformational leadership styles of inspirational motivation and idealized behavioral influence were significantly related to principals' spirituality. In addition, a multiple regression analysis including the five measures of transformational leadership as predictors suggested that spirituality is positively related to an individual's transformational leadership behaviors. A multiple regression analysis utilizing a linear combination of all transformational leadership and transactional measures was predictive of spirituality. Finally, it appears that the inspirational motivation measure of transformational leadership accounts for a significant amount of unique variance independent of the other seven transformational and transactional leadership measures in predicting spirituality. Based on the findings from this study, the researcher proposed a modification of Bass and Avolio's (1985) Full Range Leadership Model. An additional dimension, spirituality, was added to the continuum of leadership styles. The findings from this study imply that principals' self-reported levels of spirituality was related to their being perceived as displaying transformational leadership behaviors. Principals who identified themselves as "spiritual", were more likely to be characterized by the transformational leadership style of inspirational motivation.

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This paper provides a method for constructing a new historical global nitrogen fertilizer application map (0.5° × 0.5° resolution) for the period 1961-2010 based on country-specific information from Food and Agriculture Organization statistics (FAOSTAT) and various global datasets. This new map incorporates the fraction of NH+4 (and NONO-3) in N fertilizer inputs by utilizing fertilizer species information in FAOSTAT, in which species can be categorized as NH+4 and/or NO-3-forming N fertilizers. During data processing, we applied a statistical data imputation method for the missing data (19 % of national N fertilizer consumption) in FAOSTAT. The multiple imputation method enabled us to fill gaps in the time-series data using plausible values using covariates information (year, population, GDP, and crop area). After the imputation, we downscaled the national consumption data to a gridded cropland map. Also, we applied the multiple imputation method to the available chemical fertilizer species consumption, allowing for the estimation of the NH+4/NO-3 ratio in national fertilizer consumption. In this study, the synthetic N fertilizer inputs in 2000 showed a general consistency with the existing N fertilizer map (Potter et al., 2010, doi:10.1175/2009EI288.1) in relation to the ranges of N fertilizer inputs. Globally, the estimated N fertilizer inputs based on the sum of filled data increased from 15 Tg-N to 110 Tg-N during 1961-2010. On the other hand, the global NO-3 input started to decline after the late 1980s and the fraction of NO-3 in global N fertilizer decreased consistently from 35 % to 13 % over a 50-year period. NH+4 based fertilizers are dominant in most countries; however, the NH+4/NO-3 ratio in N fertilizer inputs shows clear differences temporally and geographically. This new map can be utilized as an input data to global model studies and bring new insights for the assessment of historical terrestrial N cycling changes.

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This paper proposes an allocation Malmquist index which is inspired by the work on the non-parametric cost Malmquist index. We first show that how to decompose the cost Malmquist index into the input-oriented Malmquist index and the allocation Malmquist index. An application in corporate management of the China securities industry with the panel data set of 40 securities companies during the period 2005–2011 shows the practicality of the propose model.

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We report the generation of a 13dB 2nd order Bragg resonance in a conventionally UV inscribed 45° tilted fiber grating, showing strong polarization dependency and its application for singe polarization output of a fiber laser. © 2010 Optical Society of America.

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Purpose: This paper extends the use of Radio Frequency Identification (RFID) data for accounting of warehouse costs and services. Time Driven Activity Based Costing (TDABC) methodology is enhanced with the real-time collected RFID data about duration of warehouse activities. This allows warehouse managers to have accurate and instant calculations of costs. The RFID enhanced TDABC (RFID-TDABC) is proposed as a novel application of the RFID technology. Research Approach: Application of RFID-TDABC in a warehouse is implemented on warehouse processes of a case study company. Implementation covers receiving, put-away, order picking, and despatching. Findings and Originality: RFID technology is commonly used for the identification and tracking items. The use of the RFID generated information with the TDABC can be successfully extended to the area of costing. This RFID-TDABC costing model will benefit warehouse managers with accurate and instant calculations of costs. Research Impact: There are still unexplored benefits to RFID technology in its applications in warehousing and the wider supply chain. A multi-disciplinary research approach led to combining RFID technology and TDABC accounting method in order to propose RFID-TDABC. Combining methods and theories from different fields with RFID, may lead researchers to develop new techniques such as RFID-TDABC presented in this paper. Practical Impact: RFID-TDABC concept will be of value to practitioners by showing how warehouse costs can be accurately measured by using this approach. Providing better understanding of incurred costs may result in a further optimisation of warehousing operations, lowering costs of activities, and thus provide competitive pricing to customers. RFID-TDABC can be applied in a wider supply chain.

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Oscillating Water Column (OWC) is one type of promising wave energy devices due to its obvious advantage over many other wave energy converters: no moving component in sea water. Two types of OWCs (bottom-fixed and floating) have been widely investigated, and the bottom-fixed OWCs have been very successful in several practical applications. Recently, the proposal of massive wave energy production and the availability of wave energy have pushed OWC applications from near-shore to deeper water regions where floating OWCs are a better choice. For an OWC under sea waves, the air flow driving air turbine to generate electricity is a random process. In such a working condition, single design/operation point is nonexistent. To improve energy extraction, and to optimise the performance of the device, a system capable of controlling the air turbine rotation speed is desirable. To achieve that, this paper presents a short-term prediction of the random, process by an artificial neural network (ANN), which can provide near-future information for the control system. In this research, ANN is explored and tuned for a better prediction of the airflow (as well as the device motions for a wide application). It is found that, by carefully constructing ANN platform and optimizing the relevant parameters, ANN is capable of predicting the random process a few steps ahead of the real, time with a good accuracy. More importantly, the tuned ANN works for a large range of different types of random, process.

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The primary focus of this thesis was the development of a novel chiral tether that could be used to control axial chirality around a newly formed aryl-aryl bond, and the extension of this methodology to the model synthesis of gomisin M1. In chapter 1, a review detailing the use of chiral tethers in the synthesis of atropisomers is discussed. The use of a variety of chiral molecules including 1,2-diols, 1,3-diols and other diol-based tethers, as well as amine-based and miscellaneous tethers are detailed. In chapter 2, the rationale behind the design of our novel molecular tethers, along with the subsequent synthesis of three chiral 1,3-diol-based tethers, is outlined. The method by which the enantiopurity of these diols was determined is also reviewed. This chapter also includes the attempted Mitsunobu and intramolecular couplings in the model synthesis of BINOL. Chapter 3 discusses the synthesis of suitable aryl halide substrates, and their employment in the attempted tether-controlled asymmetric model synthesis of gomisin M1. A comprehensive investigation into the attempted intramolecular biaryl coupling of these tethered substrates is also included. The non-stereoselective model synthesis of gomisin M1 is outlined in chapter 4. The installation of the desired biaryl linkage and the subsequent attempted intramolecular McMurry couplings are discussed. The impact of different protecting groups in the molecule on the intramolecular McMurry reaction is also outlined. Chapter 5 details the full experimental procedures, including spectroscopic and analytical data for the compounds prepared during this research.

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PURPOSE:
To evaluate the combination of a pressure-indicating sensor film with hydrogel-forming microneedle arrays, as a method of feedback to confirm MN insertion in vivo.
METHODS:
Pilot in vitro insertion studies were conducted using a Texture Analyser to insert MN arrays, coupled with a pressure-indicating sensor film, at varying forces into excised neonatal porcine skin. In vivo studies involved twenty human volunteers, who self-applied two hydrogel-forming MN arrays, one with a pressure-indicating sensor film incorporated and one without. Optical coherence tomography was employed to measure the resulting penetration depth and colorimetric analysis to investigate the associated colour change of the pressure-indicating sensor film.
RESULTS:
Microneedle insertion was achieved in vitro at three different forces, demonstrating the colour change of the pressure-indicating sensor film upon application of increasing pressure. When self-applied in vivo, there was no significant difference in the microneedle penetration depth resulting from each type of array, with a mean depth of 237 μm recorded. When the pressure-indicating sensor film was present, a colour change occurred upon each application, providing evidence of insertion.
CONCLUSIONS:
For the first time, this study shows how the incorporation of a simple, low-cost pressure-indicating sensor film can indicate microneedle insertion in vitro and in vivo, providing visual feedback to assure the user of correct application. Such a strategy may enhance usability of a microneedle device and, hence, assist in the future translation of the technology to widespread clinical use.

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The Sustainable Strategies Game (SSG) is being developed as ‘edutainment’ in response to the need to understand sustainable futures and advocate sustainability within workplaces in Higher Education. SSG seeks to both deliver experiential teaching and learning for business sustainability and enhance students’ learning experiences within Worcester Business School. This paper presents findings from action research undertaken to formally investigate two aspects of SSG within edutainment for ESD: firstly, it explores the value students obtain from game playing as an approach to sustainability learning. Secondly, it establishes students’ suggestions for evolutions to SSG, e.g. game design and additional features such as social media interventions or legal challenges, to increase its value as a tool for teaching and learning. Informal feedback following sessions playing SSG suggests games generally generate positive effects on students’ learning. Students highlighted SSG offered an enjoyable alternative approach to learning and could drive changes to sustainability thinking. Introducing such gameplay offers the potential to engage participants in collaborative behaviours and encourage consideration of profitability through strategies which carry less impact on the environment; vital to create a sustainable future. This paper presents qualitative evidence from game players that can enhance SSG as a tool to further improve students’ learning experience and its value as edutainment rather than entertainment within ESD.