bluuebunny/crossref_metadata_2025_split huggingface dataset:
ILGAR In2S3 buffer layers for Cd‐free Cu(In,Ga)(S,Se)2 solar cells with certified efficiencies above 16%
Authors: Sáez‐Araoz Rodrigo , Krammer Johanna , Harndt Susanna , Koehler Tristan , Krueger Martin , Pistor Paul , Jasenek Axel , Hergert Frank , Lux‐Steiner Martha Ch. , Fischer Christian‐Herbert 
Published: July 2012

ABSTRACTIn2S3 buffer layers have been prepared using the spray ion layer gas reaction deposition technique for chalcopyrite‐based thin‐film solar cells. These buffers deposited on commercially available Cu(In,Ga)(S,Se)2 absorbers have resulted in solar cells with certified record efficiencies of 16.1%, clearly higher than the corresponding CdS‐buffered references. The deposition process has been optimized, and the resulting cells have been studied using current–voltage and quantum efficiency analysis and compared with previous record cells, cells with a thermally evaporated In2S3 buffer layer and CdS references. Copyright © 2012 John Wiley & Sons, Ltd.
Formation of atom‐sized contacts of Mg and Mg alloys at room temperature
Authors: Takahashi Atsushi , Kurokawa Shu , Sakai Akira 
Published: July 2012

AbstractWe have measured the conductance of atom‐sized contacts of dilute MgZnCa and MgZnCe alloys at room temperature (RT) and found two new peaks at (1.6–1.7)G0 and (2.6–2.9)G0 (where $G_{0} \equiv 2e^{2} /h$ is the quantum unit of conductance) in their conductance histograms. Because the solute level in these alloys is too low to affect the contact conductance, these peaks can be considered as low‐conductance peaks of pure Mg, which have not been observed in the histogram of pure Mg at RT [Smit et al., New J. Phys. 11, 073043 (2009)]. The MgZnCa and MgZnCe alloys differ from pure Mg primarily in their superior ductility. Thus, the observation of new peaks for these alloys suggests that the absence of low‐conductance peaks below 4G0 in the room‐temperature histogram of pure Mg is likely related to the plasticity of Mg.
Embrittlement of a bulk metallic glass containing ductile phase after low‐temperature annealing
Authors: Kong Jian , Ye Zhitao , Li Jianliang , Chen Wen , Ma Xuan 
Published: July 2012

AbstractZr56.2Ti13.8Nb5.0Cu6.9Ni5.6Be12.5 bulk metallic glass composite containing in situ dendritic β‐phase is toughened by the slipping/twinning of dendrites and propagation prohibition of shear bands. After annealing, the yield strength and fracture strength of the composite increase together with a loss in plasticity. With the increase of annealing temperature, the twin crystals within the dendrites vanish gradually accompanied with the transition of β‐Zr to α‐Zr. The composite shows typical brittle fracture under the compressive condition after isochronal annealing during 583–613 K.
Spin polarization in wurtzite Zn1−xCrxS from first principles
Authors: Lakdja Abdelaziz , Mesri Dalila , Rozale Habib , Chahed Abbes , Ruterana Pierre 
Published: July 2012

AbstractWe report a first‐principles investigation of the electronic and magnetic properties of wurtzite Zn1−xCrxS alloy. Results on total energy calculations exhibit a ferromagnetic (FM) state at low Cr concentration of 25%, while for high concentration the compound has an antiferromagnetic ordering. We focused on the exchange interactions induced by the partially filled bands of the 3d Cr, which govern the magnetic properties in such material.
FLOOD INUNDATION MAPPING FOR INTEGRATED FLOODPLAIN MANAGEMENT: UPPER MISSISSIPPI RIVER SYSTEM
Authors: Theiling C. H. , Burant J. T. 
Published: July 2012

ABSTRACTNatural hydrogeomorphic characteristics and hydrologic alterations are important ecological drivers, and hydrology is also a common ecological, flood control and navigation system indicator. Hydrologic characteristics change dramatically from one end of the Upper Mississippi River System to the other, and hydraulic characteristics also differ spatially across the river channels and floodplain in response to dams, levees and diversions. Low flow surface water spatial change in response to navigation and flood control has been well known for many years, but little information was available on the spatial distribution of frequent floods. The flow frequency data presented here were developed to better estimate contemporary floods after historic flooding in 1993. Flood stage estimates are enhanced in GIS to help quantify and map potential floodplain inundation for more than 1000 river miles on the Upper Mississippi and Illinois Rivers. Potential flood inundation is mapped for the 50% to 0.2% annual exceedance probability flood stage (i.e. 2‐ to 500‐year expected recurrence interval flood) and also for alternative floodplain management scenarios within the existing flood protection infrastructure. Our analysis documents: (i) impoundment effects, (ii) a hydrologic gradient within the navigation pools that creates repeating patterns of riverine, backwater and impounded aquatic habitat conditions, (iii) potential floodplain inundation patterns for over 2 million acres and (iv) several integrated floodplain management scenarios. Extreme flood events are more common in recent decades, and they are expected to continue to occur at greater frequency in response to climate change. Floodplain managers can use the results presented here to help optimize land management and flood damage reduction on the Upper Mississippi River System. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
Performance‐based logistics and technology refreshment programs: Bridging the operational‐life performance capability gap in the Spanish F‐100 frigates
Authors: Sols Alberto , Romero Javier , Cloutier Robert 
Published: July 2012

AbstractMany large and complex systems have extended operational lives. Examples of such systems include the oil and gas drilling systems, defense systems, and air traffic control systems. A growing concern for many users is the difference between actual and intended system performance during the operational life. An understanding of the root causes of that gap, known as performance capability gap, is required if appropriate measures are to be taken. This paper explores the main reasons for the existence of the performance capability gap and suggests the combination of performance‐based logistics and technology refreshment programs as a very effective and efficient remedial strategy. The paper examines the Spanish F‐100 frigate to illustrate actual application of these strategies. © 2012 Wiley Periodicals, Inc. Syst Eng 15
Budget‐constrained portfolio trades using multiobjective optimization
Authors: Smith Patrick , Ferringer Matthew , Kelly Ryan , Min Inki 
Published: July 2012

AbstractA decision support process using many‐objective optimization, high‐performance computing, and advanced visualization is applied to gain comprehensive insight into multistakeholder portfolio budgeting trades. The key tradeoffs among nondominated portfolio budget solutions are systematically identified and examined with respect to different stakeholder viewpoints. The approach is illustrated using a portfolio of 14 U.S. Air Force satellite development programs using budget data taken from the 2010 Future Year Development Plan [http://www.saffm.hq.af.mil/budget/, last accessed April 20, 2011]. Practical lessons learned in applying the approach are discussed. ©2012 Wiley Periodicals, Inc. Syst Eng 15
On principles and rules in complex adaptive systems: A financial system case study
Authors: Polacek George A. , Gianetto David A. , Khashanah Khaldoun , Verma Dinesh 
Published: July 2012

AbstractSystems engineers have always been concerned with the problems surrounding complex systems. An evolutionary class of complex systems called Complex Adaptive Systems (CAS) is even more relevant today as we struggle to understand and cope with the often undesirable emergence effects of some of these systems, evidenced by recurring financial and sociopolitical crises. A key characteristic of CAS is a large, diverse, and sometimes unknown set of interactions both internally and across the system boundary. For the purpose of managing this complexity we present in this paper the concept that a principles orientation as compared to rules orientation of a complex system is an important and useful characteristic in need of further study. The US financial system is used as a CAS exemplar in support of this inquiry. ©2012 Wiley Periodicals, Inc. Syst Eng 15
Contracting processes and structures for systems‐of‐systems acquisition
Authors: Rendon Rene G. , Huynh Thomas V. , Osmundson John S. 
Published: July 2012

AbstractAcquisition of a system‐of‐systems can be an all new acquisition of multiple systems that are intended to operate together as a system‐of‐systems. Much more common in the U.S. Department of Defense (DoD) is acquisition of one or more new systems that are intended to interoperate with existing systems as a system of systems (SoS) with new capabilities. In either case, successful SoS acquisition necessarily depends on effective contracting structures and processes for SoS acquisition. In this paper, a set of issues that need to be addressed in SoS acquisition are identified, and the current findings discussed. The findings suggest maintaining an extensive systems engineering effort within the SoS acquisition and changes to the existing contracting processes, structures, and organizational structures to maximize the probability of SoS acquisition success. The resulting changes are recommended to current and future DoD SoS acquisitions. ©2012 Wiley Periodicals, Inc. Syst Eng 15
Evaluating deep uncertainties in strategic priority‐setting with an application to facility energy investments
Authors: Karvetski Christopher W. , Lambert James H. 
Published: July 2012

AbstractA recent paper in this journal described the identification and integration of sources of risk in a systems engineering process model [Lambert, Jennings, and Joshi, Syst Eng 9(3) (2006), 187–198]. The earlier effort falls short in addressing sources of deep, nonprobabilistic uncertainty that should enter to strategic systems design and reengineering. Our new paper incorporates the earlier effort to a framework for evaluating which are the deep uncertainties that most influence a priority‐setting among investments in large‐scale systems with multiple stakeholders, and therefore warrant more investigation. The framework addresses that deep uncertainties are continuously discovered and reflective of diverse and unique stakeholder experiences, knowledge bases, and advocacy positions. Deep uncertainties are epistemic viewpoints across which the strategic priorities for investments will differ. The framework modifies existing tools of scenario analysis and multicriteria analysis to process and filter the deep uncertainties. The framework is demonstrated in an application to reengineering of an energy system for a defense installation where frequent outages are disruptive to scientific and other missions. The sources of deep uncertainty in the demonstration include regulatory, economic, environment, cyber‐threat, and others. The investments include innovative microturbine and microgrid technologies. An example of a result is thatinternational economic disruptionis relatively more influential thancyber‐threatsto strategic priority‐setting for investing in a microgrid at the particular installation. ©2012 Wiley Periodicals, Inc. Syst Eng 15
Cognitive foundations for science assessment design: Knowing what students know about evolution
Authors: Opfer John E. , Nehm Ross H. , Ha Minsu 
Published: July 2012

AbstractTo improve assessments of academic achievement, test developers have been urged to use an “assessment triangle” that starts with research‐based models of cognition and learning [NRC (2001)Knowing what students know: The science and design of educational assessment. Washington, DC: National Academy Press]. This approach has been successful in designing high‐quality reading and math assessments, but less progress has been made for assessments in content‐rich sciences such as biology. To rectify this situation, we applied the “assessment triangle” to design and evaluate new items for an instrument (ACORNS, Assessing Contextual Reasoning about Natural Selection) that had been proposed to assess students' use of natural selection to explain evolutionary change. Design and scoring of items was explicitly guided by a cognitive model that reflected four psychological principles: with development of expertise, (1) core concepts facilitate long‐term recall, (2) causally‐central features become weighted more strongly in explaining phenomena, (3) normative ideas co‐exist but increasingly outcompete naive ideas in reasoning, and (4) knowledge becomes more abstract and less specific to the learning situation. We conducted an evaluation study with 320 students to examine whether scores from our new ACORNS items could detect gradations of expertise, provide insight into thinking about evolutionary change, and predict teachers' assessments of student achievement. Findings were consistent with our cognitive model, and ACORNS was revealing about undergraduates' thinking about evolutionary change. Results indicated that (1) causally‐central concepts of evolution by natural selection typically co‐existed and competed with the presence of naïve ideas in all students' explanations, with naïve ideas being especially prevalent in low‐performers' explanations; (2) causally‐central concepts were elicited most frequently when students were asked to explain evolution of animals and familiar plants, with influence of superficial features being strongest for low‐performers; and (3) ACORNS scores accurately predicted students' later achievement in a college‐level evolution course. Together, findings illustrate usefulness of cognitive models in designing instruments intended to capture students' developing expertise. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 744–777, 2012
Developing and evaluating instructionally sensitive assessments in science
Authors: Ruiz‐Primo Maria Araceli , Li Min , Wills Kellie , Giamellaro Michael , Lan Ming‐Chih , Mason Hillary , Sands Deanna 
Published: July 2012

AbstractThe purpose of this article is to address a major gap in the instructional sensitivity literature on how to develop instructionally sensitive assessments. We propose an approach to developing and evaluating instructionally sensitive assessments in science and test this approach with one elementary life‐science module. The assessment we developed was administered to 125 students in seven classrooms. The development approach considered three dimensions of instructional sensitivity; that is, assessment items should: represent the curriculum content, reflect the quality of instruction, and have formative value for teaching. Focusing solely on the first dimension, representation of the curriculum content, this study was guided by the following research questions: (1) What science module characteristics can be systematically manipulated to develop items that prove to be instructionally sensitive? and (2) Are the instructionally sensitive assessments developed sufficiently valid to make inferences about the impact of instruction on students' performance? In this article, we describe our item development approach and provide empirical evidence to support validity arguments about the developed instructionally sensitive items. Results indicated that: (1) manipulations of the items at different proximities to vary their sensitivity were aligned with the rules for item development and also corresponded with pre‐to‐post gains; and (2) the items developed at different distances from the science module showed a pattern of pre‐to‐post gain consistent with their instructional sensitivity, that is, the closer the items were to the science module, the larger the observed gains and effect sizes. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 691–712, 2012
The effect of an instructional intervention on middle school english learners' science and english reading achievement
Authors: Lara‐Alecio Rafael , Tong Fuhui , Irby Beverly J. , Guerrero Cindy , Huerta Maggie , Fan Yinan 
Published: July 2012

AbstractThis study examined the effect of a quasi‐experimental project on fifth grade English learners' achievement in state‐mandated standards‐based science and English reading assessment. A total of 166 treatment students and 80 comparison students from four randomized intermediate schools participated in the current project. The intervention consisted of on‐going professional development and specific instructional science lessons with inquiry‐based learning, direct and explicit vocabulary instruction, integration of reading and writing, and enrichment components including integration of technology, take‐home science activities, and university scientists mentoring. Results suggested a significant and positive intervention effect in favor of the treatment students as reflected in higher performance in district‐wide curriculum‐based tests of science and reading and standardized tests of oral reading fluency. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 987–1011, 2012
Instruction and cognition
Authors: Cromley Jennifer G. , Byrnes James P. 
Published: July 2012

AbstractWhen teachers provide instruction to students, they provide opportunities for students to learn information. To be maximally effective, these opportunities should present information in ways that are compatible with the way the mind works. Using a US Department of Education Practice Guide as a structure for our review, we review ‘second wave’ cognitive science research on spaced learning, worked examples, coordinating visual and verbal representations, coordinating and concrete representations, quizzing, delayed Judgment of Learning, and explanatory reasoning. We also contextualize these lines of research within the contemporary K‐12 classroom environment and constraints on teachers and school administrators. We close by advocating that all stakeholders in the instructional process also remember ‘first wave’ cognitive science findings, and also recommend more research on how specific motivational constructs could be brought to bear to encourage students to use these proven but effortful learning principles. WIREs Cogn Sci 2012 doi: 10.1002/wcs.1192This article is categorized under:

Psychology > Learning
Numerical investigation of unsteady aerodynamics of a Horizontal‐axis wind turbine under yawed flow conditions
Authors: Yu Dong Ok , You Ju Yeol , Kwon Oh Joon 
Published: July 2012

ABSTRACTIn the present study, unsteady flow features and the blade aerodynamic loading of the National Renewable Energy Laboratory phase VI wind turbine rotor, under yawed flow conditions, were numerically investigated by using a three‐dimensional incompressible flow solver based on unstructured overset meshes. The effect of turbulence, including laminar‐turbulent transition, was accounted for by using a correlation‐based transition turbulence model. The calculations were made for an upwind configuration at wind speeds of 7, 10 and 15 m/sec when the turbine rotor was at 30° and 60° yaw angles. The results were compared with measurements in terms of the blade surface pressure and the normal and tangential forces at selected blade radial locations. It was found that under the yawed flow conditions, the blade aerodynamic loading is significantly reduced. Also, because of the wind velocity component aligned tangent to the rotor disk plane, the periodic fluctuation of blade loading is obtained with lower magnitudes at the advancing blade side and higher magnitudes at the retreating side. This tendency is further magnified as the yaw angle becomes larger. At 7 m/sec wind speed, the sectional angle of attack is relatively small, and the flow remains mostly attached to the blade surface. At 10 m/sec wind speed, leading‐edge flow separation and strong radial flow are observed at the inboard portion of the retreating blade. As the wind speed is further increased, the flow separation and the radial flow become more pronounced. It was demonstrated that these highly unsteady three‐dimensional aerodynamic features are well‐captured by the present method. Copyright © 2012 John Wiley & Sons, Ltd.
Migration Systems in Europe: Evidence From Harmonized Flow Data
Authors: DeWaard Jack , Kim Keuntae , Raymer James 
Published: July 2012

AbstractEmpirical tests of migration systems theory require consistent and complete data on international migration flows. Publicly available data, however, represent an inconsistent and incomplete set of measurements obtained from a variety of national data collection systems. We overcome these obstacles by standardizing the available migration reports of sending and receiving countries in the European Union and Norway each year from 2003–2007 and by estimating the remaining missing flows. The resulting harmonized estimates are then used to test migration systems theory. First, locating thresholds in the size of flows over time, we identify three migration systems within the European Union and Norway. Second, examining the key determinants of flows with respect to the predictions of migration systems theory, our results highlight the importance of shared experiences of nation-state formation, geography, and accession status in the European Union. Our findings lend support to migration systems theory and demonstrate that knowledge of migration systems may improve the accuracy of migration forecasts toward managing the impacts of migration as a source of social change in Europe.
The main trunk of the left bundle branch is not part of the re‐entry circuit of verapamil‐sensitive idiopathic left ventricular tachycardia
Authors: Nakagawa Eiichiro , Takagi Masahiko , Abe Yukio , Komatsu Rhyshi , Haze Kazuo , Naruko Takahiko , Itoh Akira 
Published: July 2012

AbstractWe report the case of a 19‐year‐old man with verapamil‐sensitive idiopathic left ventricular tachycardia (ILVT), who had paroxysmal palpitations for 3 years. Programmed right atrial and ventricular stimulation easily induced ventricular tachycardia (VT) with QRS duration of 125 ms, right bundle branch block pattern, and right inferior axis, which are characteristics of ILVT. Left ventricular endocardial mapping accidentally produced a complete left bundle branch block and provoked prolongation of the QRS duration of VT, which was 143 ms. However, no changes occurred in the cycle length, inducibility, or maintenance of VT. The VT was eliminated successfully by catheter ablation at the pre‐Purkinje potential (PP) recording site. These findings suggest that the main trunk of the left bundle branch is not a critical component of the re‐entry circuit of ILVT.
Optimizing heart failure therapy with implantable sensors
Authors: Lau Chu‐Pak , Siu David C.W. , Tse Hung‐Fat 
Published: July 2012

AbstractHeart failure (HF)‐related hospitalization is associated with significant mortality and morbidity and can be prevented by early intervention. Implantable sensors detect early pathophysiological changes in HF, using an accelerometer, a paced electrogram, impedance and pressure sensors in implanted intracardiac leads, or stand‐alone devices. Such sensors monitor daily activity, QT and ST intervals, pulmonary fluid, and intracardiac pressures at various points. Sensor data are available either by patient's or physician's regular interrogation, or using remote patient monitoring. Different sensors have different levels of sensitivity and specificity for HF detection, and they have the ability to antedate HF exacerbation and thereby allow for the initiation of intervention to avert decompensation. Clinical studies suggest that alone or in combination, such sensors have a greater beneficial impact than conventional therapy on acute HF outcome.