bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure analysis of thin‐film four‐junction inverted metamorphic solar cells
Authors: Long Junhua , Wu Dongying , Huang Xinping , Ye Sai , Li Xuefei , Ji Lian , Sun Qiangjian , Song Minghui , Xing Zhiwei , Lu Shulong 
Published: November 2020

AbstractInverted metamorphic solar cells play an important role in the field of photovoltaics, because it can directly grow stacked tandem junctions with different bandgaps according to the spectrum. We have found that the four‐junction AlGaInP/AlGaAs/InGaAs/InGaAs solar cells with the bandgap of 1.96/1.55/1.17/0.83 eV on the basis of the inverted metamorphic three‐junction AlGaInP/AlGaAs/InGaAs materials will cause a serious decrease in short‐circuit current density but with a normal open‐circuit voltage. The sharp decrease in short‐circuit current density is not attributed to the mismatched buffers dislocations penetrating into the active region of the InGaAs subcells but resulted from the minority carrier recombination due to defects in the AlGaInP subcell, which is observed directly from transmission electron microscopy, external quantum efficiency, electroluminescence, and secondary ion mass spectrometry measurements. The process of growing AlGaInP materials by metal–organic chemical vapor deposition easily introduces Al‐O deep‐level defects, resulting in the poor collection of minority carriers in AlGaInP materials. After improving the growth conditions of AlGaInP materials, a four‐junction solar cell with a photoelectric conversion efficiency of 34.9% and an open‐circuit voltage of 3.53 V was obtained.
A real‐time quadrotor trajectory planning framework based on B‐spline and nonuniform kinodynamic search
Authors: Tang Lvbang , Wang Hesheng , Liu Zhe , Wang Yong 
Published: November 2020

AbstractAutonomous navigation of quadrotor is required by many application scenarios, such as exploration, search, and rescue. The trajectory planning algorithm is the core of autonomous navigation, which can undoubtedly greatly enhance the safety of flight. In this paper, a trajectory planning framework based on B‐spline and kinodynamic search is proposed. This framework can be used for a limited‐sensing quadrotor to plan safe and dynamically feasible trajectories in unknown environments, and the flight is safe and effective along with these trajectories. First, a B‐spline based nonuniform kinodynamic (BNUK) search algorithm is proposed to generate dynamically feasible trajectories efficiently. The characteristics of nonuniform search make the generated trajectories safe and reasonable time‐allocation. Then, a trajectory optimization method based on control point optimization is proposed. The trajectory generated by BNUK is further optimized by solving a quadratically constrained quadratic programming problem. The smoothness of the trajectory is improved, and the control cost is reduced. Extensive analysis and comparative simulation experiments verify the advancedness of the proposed framework. We also integrated it into a vision‐based quadrotor autonomous navigation system, and multiple outdoor flight experiments show the effectiveness of the proposed framework.
Development and application of the Hydric Soil Technical Standard
Authors: Berkowitz Jacob F. , Vepraskas Michael J. , Vaughan Karen L. , Vasilas Lenore M. 
Published: November 2020

AbstractThe concept of hydric soils evolved over time with advances in soil science and wetland resource management. Hydric soils are identified in the field by examining morphological characteristics, including organic matter accumulation and redoximorphic features that form in response to prolonged periods of saturation and anaerobic conditions. The Hydric Soil Technical Standard (HSTS) was developed to provide a quantitative procedure for evaluating the hydric status of a soil based upon direct measurements of saturation, anaerobic conditions, and precipitation normality. In practice, the HSTS is used for (a) identifying hydric soils when a field indicator of hydric soils may not be present (e.g., naturally problematic or disturbed soils); (b) evaluating the current functional hydric status of a soil; (c) developing new field indicators of hydric soils; and (d) proposing changes to existing field indicators of hydric soils. The HSTS procedures have progressed over several decades with new approaches to soil analysis, including novel methods to document anaerobic conditions. The following review describes the development of the hydric soils concept and provides guidance for measuring each HSTS component. Practical approaches for collection and submission of HSTS data to the National Technical Committee for Hydric Soils, the group responsible for approving approaches to hydric soil identification in the United States, are also discussed. Expanding the understanding and application of the HSTS promotes technical accuracy, transparency, and efficient decision making in support of hydric soil and wetland resource management.
Study on adaptive‐passive eddy current pendulum tuned mass damper for wind‐induced vibration control
Authors: Wang Liangkun , Nagarajaiah Satish , Shi Weixing , Zhou Ying 
Published: November 2020

SummaryTuned mass dampers (TMDs) are used to control wind‐excited responses of high‐rise building as traditional vibration control devices. A TMD will have an excellent control effect when it is well tuned. However, a traditional passive TMD is sensitive to the frequency deviation; the mistuning in frequency and damping ratio both will decrease its control effect. In the previous research, an adaptive‐passive variable pendulum TMD (APVP‐TMD) is proposed, which can identify the TMD optimal frequency and retune itself through varying its pendulum length. However, it is found that the frequency variation will change the TMD damping ratio, and an unreasonable damping ratio will lead to a decrement in the robustness of a TMD. In this study, an adaptive‐passive eddy current pendulum TMD (APEC‐PTMD) is presented, which can retune the frequency through varying the pendulum length, and retune the damping ratio through adjusting the air gap between permanent magnets and conductive plates. An adjustable eddy current pendulum TMD (PTMD) is tested, and then, a single‐degree‐of‐freedom (SDOF) primary model with an APEC‐PTMD is built, and functions of frequency and damping ratio retuning are verified. The 76‐story wind‐sensitive benchmark model is proposed in the case study. The original model without uncertainty and ±15% stiffness uncertainty models are considered, and response control effects of different controllers are compared. Results show that because the APEC‐PTMD can both retune its frequency and damping ratio; it is more robust and effective than a passive TMD. It is also found that the APEC‐PTMD has a similar control effect with the active TMD, with little power consumption and better stability.
Literacy in Lockdown: Learning and Teaching During COVID‐19 School Closures
Authors: Chamberlain Liz , Lacina Jan , Bintz William P. , Jimerson Jo Beth , Payne Kim , Zingale Remy 
Published: November 2020

AbstractAcross the globe, students have been away from schools and their teachers, but literacy learning has continued. In many countries, students’ literacy proficiency is often measured via high‐stakes assessment tests. However, such tests do not make visible students’ literacy lives away from formal learning settings, so students are positioned as task responders, rather than as agentive readers and writers. The authors explore the fluidity and diversity of literacy events and practices for students and their teachers observed during the recent period of COVID‐19 lockdown restrictions.
Chemical and biological indicators of soil health in Chicago urban gardens and farms
Authors: Ugarte Carmen M. , Taylor John R. 
Published: November 2020

AbstractUrban food production is conducted in highly heterogeneous environments that have undergone considerable manipulation by building, demolition, and/or industrial pollution. This study evaluated soil quality characteristics in urban sites currently used for vegetable production across an urban to peri‐urban gradient in Chicago, IL, USA. Twenty‐one sites were classified based on the scale of management as private home gardens, community gardens, institutional farms, and private urban farms. We quantified indicators of soil fertility, nematode trophic composition, and indicators of the food web status (Maturity Index, Enrichment Index, Channel Index, and Structure Index). We also quantified concentrations of soil contaminants including lead (Pb), arsenic (As), and zinc (Zn). Analysis of free‐living nematode families suggested that communities differ across sites based on their scale of management and are likely influenced by soil organic matter and soil pH. Concentrations of Pb, As, and Zn were below the levels of concern and did not influence nematode community structure. Finally, soil fertility was significantly increased by management, particularly in community gardens and urban farms. Adoption of best management practices in urban agriculture, such as reduced mixing through tillage, and the use of soil testing as a decision‐support tool that helps optimize compost application, would reduce potential ecosystem disservices and promote food webs with greater functional diversity.
Building Opportunities for Learning Multiplication
Authors: Mendes Fátima , Brocardo Joana , Oliveira Hélia 
Published: November 2020

AbstractThis chapter seeks to illustrate a comprehension-based learning approach focused on multiplication. We use episodes to show the potential of a teaching design of multiplication focused on the development of mental calculation based on tasks with appropriate contexts and calculations anchored in the use of benchmark numbers and operation properties, with examples to explain the ideas that are introduced. They are based on a collaborative work experience between a third-grade primary teacher and a researcher (the first author of this chapter). Using these specific examples, we discuss mathematical ideas and didactic options that can guide the actions of teachers when teaching multiplication. Finally, we discuss some points of convergence between the approach introduced here and the lesson study approach.
Multiplication of Whole Numbers in the Curriculum: Singapore, Japan, Portugal, the USA, Mexico, Brazil, and Chile
Authors: Olfos Raimundo , Isoda Masami , Estrella Soledad 
Published: November 2020

AbstractThis chapter shows how the teaching of multiplication is structured in national curriculum standards (programs) around the world. (The documents are distributed by national governments via the web. Those documents are written in different formats and depths. For understanding the descriptions of the standards, we also refer to national authorized textbooks for confirmation of meanings.) The countries chosen for comparison in this case are two countries in Asia, one in Europe, two in North America, and two in South America: Singapore, Japan, Portugal, the USA (where the Common Core State Standards (2010) are not national but are agreed on by most of the states), Mexico, Brazil, and Chile, from the viewpoint of their influences on Ibero-American countries. (The National Council of Teachers of Mathematics (NCTM) standards (published in 2000) and the Japanese and Singapore textbooks have been influential in Latin America. Additionally, Portugal was selected to be compared with Brazil). To distinguish between each country’s standard and the general standards described here, the national curriculum standards are just called the “program.” The comparison shows the differences in the programs for multiplication in these countries in relation to the sequence of the description and the way of explanation. The role of this chapter in Part I of this book is to provide the introductory questions that will be discussed in Chaps. 3, 4, 5, 6, and 7 to explain the features of the Japanese approach. (As is discussed in Chap. 1, the Japanese approach includes the Japanese curriculum, textbooks, and methods of teaching which can be used for designing classes, as has been explored in Chile (see (Estrella, Mena, Olfos, Lesson Study in Chile: a very promising but still uncertain path. In Quaresma, Winsløw, Clivaz, da Ponte, Ní Shúilleabháin, Takahashi (eds), Mathematics lesson study around the world: Theoretical and methodological issues. Cham: Springer, pp. 105–122, 2018). The comparison focuses on multiplication of whole numbers. In multiplication, all of these countries seem to have similar goals—namely, for their students to grasp the meaning of multiplication and develop fluency in calculation. However, are they the same? By using the newest editions of each country’s curriculum standards, comparisons are done on the basis of the manner of writing, with assigned grades for the range of numbers, meanings, expression, tables, and multidigit multiplication. The relationship with other specific content such as division, the use of calculators, the treatment of multiples, and mixed arithmetic operations are beyond the scope of this comparison. Those are mentioned only if there is a need to show diversity.
Problematics for Conceptualization of Multiplication
Authors: Isoda Masami , Olfos Raimundo 
Published: November 2020

AbstractThis chapter addresses the problematics for the conceptualization of multiplication in school mathematics and fundamental difficulties, which include semantics for defining multiplication meaningfully, syntax in relation to languages, and difficulties that originate from historical transitions. The chapter discusses the contradictions or inconsistencies in the various meanings of multiplication in school mathematics situations. Many of these problems of multiplication are originated from European languages. This discussion of these problematics provides some answers to the questions posed in Chap. 2 and provides bases for the necessity to consider the Japanese approach described in Chaps. 4, 5, 6, and 7 of this book. The terminology of multiplication discussed here is related to mathematical usages of multiplication in relation to situations and models. Educational terminology used for multiplication to explain the curriculum and task sequences for designing lessons are discussed in Chap. 4 of this book.
Teaching the Multiplication Table and Its Properties for Learning How to Learn
Authors: Olfos Raimundo , Isoda Masami 
Published: November 2020

AbstractWhy do the Japanese traditionally introduce multiplication up to the multiplication table in the second grade? There are four possible reasons. The first reason is that it is possible to teach. The second reason is that Japanese teachers plan the teaching sequence to teach the multiplication table as an opportunity to teach learning how to learn. The third reason is that memorizing the table itself has been recognized as a cultural practice. The fourth reason is to develop the sense of wonder with appreciation of its reasonableness. The second and the fourth reasons are discussed in Chap. 1 of this book as “learning how to learn” and “developing students who learn mathematics by and for themselves in relation to mathematical values, attitudes, ways of thinking, and ideas.” This chapter describes these four reasons in this order to illustrate the Japanese meaning of teaching content by explaining how the multiplication table and its properties are taught under the aims of mathematics education. In Chap. 1, these were described by the three pillars: human character formation for mathematical values and attitudes, mathematical thinking and ideas, and mathematical knowledge and skills.
An Ethnomathematical Perspective on the Question of the Idea of Multiplication and Learning to Multiply: The Languages and Looks Involved
Authors: Sabba Claudia Georgia , D’Ambrosio Ubiratan 
Published: November 2020

AbstractThis chapter invites appreciation of the development of an ethnomathematical perspective on the question of the idea of multiplication. The teaching approach described here is grounded on miniprojects that integrate diverse areas of knowledge. It reveals a style of work being performed in the Waldorf Schools of São Paulo, Brazil, where the concept of multiplication is constructed together with the geometry of plane figures through the elaboration of mathematical thinking together with figures mounted on a circular wooden table. The sequence highlights ideas of context connected to the use of cellular phones by the students to introduce the concept of proportionality by taking photos of their bodies and faces, and then using them to study Leonardo da Vinci’s Vitruvian Man.
Biochar–Compost Mixtures as a Promising Solution to Organic Waste Management Within a Circular Holistic Approach
Authors: Varalta Federico , Sorvari Jaana 
Published: November 2020

AbstractIn the common linear economy approach, organic waste treatment mainly generates energy, due to the existing demand and the goal of reducing the use of fossil fuel. Yet recent innovations and associated products are calling for an increasingly diverse use of organic waste within a circular holistic framework where the biochar and composting mixture appears to be the key to achieving a robust solution for sustainable development. Nonetheless, the inhomogeneity of organic waste and the synergies between biochar and composting require further investigation before broad-scale field application. In this chapter, we illustrate how governmental policies should be updated and revised to effectively support the development of new sustainable solutions, that should take into account social, economic and environmental implications, as well as their mutual interactions. As a consequence, robust tools and reliable procedures to evaluate sustainability will have to be established in this new ecological structure.
Role of Cassava and Sweetpotato in Mitigating Drought in Semi-Arid Makueni County in Kenya
Authors: Githunguri C. M. , Njiru E. N. 
Published: November 2020

AbstractCassava and sweetpotato are major factors in food security across sub-Saharan Africa. Though cassava and sweetpotato varieties that are early maturing and resistant to diseases have been developed, many farmers still grow local varieties. Cassava and sweetpotato cultivars that mature between 6 and 12 and 3 and 4 months after planting, respectively, are available. The objective of the synthesis was to obtain a general overview of cassava and sweetpotato production in Matiliku subcounty of Makueni County in semi-arid eastern Kenya before the establishment of a seed system for them. Participatory rural appraisal and focused group discussions with key stakeholders in Makueni County on the current status of these crops provided very useful information. It was observed that there are a few early cassava and sweetpotato adopters, meaning a lot of effort in communicating the need to commercialize them needs to be made. Even though the farmers had sufficient experience in growing them at subsistence level, they were searching for cultivars that combine both nutritional and food security. There is a need to engage more extension service providers in order to campaign on their adoption. There is a need to carryout training and awareness creation on their role in food security and wealth creation.
Estonia: A Positive PISA Experience
Authors: Tire Gunda 
Published: November 2020

AbstractAccording to Programme for International Student Assessment (PISA) run by Organization of Economic Cooperation and Development (OECD), Estonian education system stands out as a high performing system where students from different socio-economic backgrounds achieve high results. In PISA 2018 Estonian students ranked first in reading and science and third in mathematics among the OECD countries. What has Estonia done to be at the top of the PISA league tables? There are many aspects that have contributed to the success of Estonian education. The following chapter will look at the historical background, describe the factors, policies and conditions that have contributed to the current educational landscape that has attracted considerable attention from all over the world.
In Memory of Sergey G. Psakhie
Authors: Shilko Evgeny V. , Popov Valentin L. , Vasiljeva Olga S. , Ostermeyer Georg-Peter 
Published: November 2020

AbstractThis introductory chapter is dedicated to the life and work of Sergey Grigirievich Psakhie, his outstanding contributions to the development of science and education in Russia and especially in the Tomsk region as well as to his numerous international collaborations and research interests. It further includes personal notes from some of his closest collaborators: Georg-Peter Ostermeyer, Valentin L. Popov, Lev B. Zuev and Valery V. Ruzich. The Chapter is concluded by an overview of Sergey G. Psakhie’s most significant scientific publications.
Application of Crumpled Aluminum Hydroxide Nanostructures for Cancer Treatment
Authors: Lozhkomoev Aleksandr S. , Mikhaylov Georgy , Turk Vito , Turk Boris , Vasiljeva Olga 
Published: November 2020

AbstractThe tumormicroenvironment regulates tumor progression and the spread of cancer in the body. Applications of nanomaterials that can dysregulate tumor-microenvironment are emerging as a promising anti-cancer approaches, which can improve the efficacy of existing cancer treatments. We have reported that agglomerates of radially assembled Al hydroxide crumpled nanosheets with the disordered defective surface structure have a large positive charge and therefore can lead to ion imbalance at the cell perimembranous space through the selective adsorption of extracellular anionic species. This effect was demonstrated in vitro by reduced viability and proliferationof tumor cells, and further validated in a murine melanoma cancer model. Furthermore, crumpled Al hydroxide nanostructures showed a much stronger suppressive effect on tumor growth in combination with a minimally effective dose of doxorubicin. Taken together, the described approach of tumor microenvironment dysregulation through selective adsorption properties of folded crumpled nanostructures opened a new avenue for development of innovative anticancer therapy strategies.
Microstructure-Based Computational Analysis of Deformation and Fracture in Composite and Coated Materials Across Multiple Spatial Scales
Authors: Balokhonov Ruslan R. , Romanova Varvara A. 
Published: November 2020

AbstractA multiscale analysis is performed to investigate deformation and fracture in the aluminum-alumina composite and steel with a boride coating as an example. Model microstructure of the composite materials with irregular geometry of the matrix-particle and substrate-coating interfaces correspondent to the experimentally observed microstructure is taken into account explicitly as initial conditions of the boundary value problem that allows introducing multiple spatial scales. The problem in a plane strain formulation is solved numerically by the finite-difference method. Physically-based constitutive models are developed to describe isotropic strain hardening, strain rate and temperature effects, Luders band propagation and jerky flow, and fracture. Local regions experiencing bulk tension are found to occur during compression that control cracking of composites. Interrelated plastic strain localization in the steel substrate and aluminum matrix and crack origination and growth in the ceramic coating and particles are shown to depend on the strain rate, particle size and arrangement, as well as on the loading direction: tension or compression.