Mathematical Chemistry

OpenAIRE

Trinajstić, Nenad; Gutman, Ivan

2002-01-01

A brief description is given of the historical development of mathematics and chemistry. A path leading to the meeting of these two sciences is described. An attempt is made to define mathematical chemistry, and journals containing the term mathematical chemistry in their titles are noted. In conclusion, the statement is made that although chemistry is an experimental science aimed at preparing new compounds and materials, mathematics is very useful in chemistry, among other things, to produc...

Mathematical Making in Teacher Preparation: What Knowledge Is Brought to Bear?

Science.gov (United States)

Greenstein, Steven; Seventko, Justin

2017-01-01

In this paper, we describe an experience within mathematics teacher preparation that engages preservice teachers (PSTs) in Making and design practices that we hypothesized would inform their conceptual and pedagogical thinking. With a focus on the design of new tools to support mathematics teaching and learning, this Learning by Design experience…

A Review of New Mathematics Curriculum Materials.

Science.gov (United States)

Vanderlin, Carl J., Jr.

This manual outlines the nature of some of the major curriculum projects in mathematics and lists materials which are available from these projects. An introductory statement concerning the history and philosophy of each program is indicated. The curriculum projects reported on are: (1) Boston College Mathematics Institute, (2) Cambridge…

Rethinking Teacher Preparation: Conceptualizing Skills and Knowledge of Novice Teachers of Secondary Mathematics

Science.gov (United States)

Cummings, Margarita Borelli

2010-01-01

This dissertation examines the extent to which novice secondary mathematics teachers (licensed and currently teaching in Utah) perceive they are prepared to do the work of teaching secondary mathematics. It first examined if novice secondary mathematics teachers' perceptions of their knowledge and skills of doing their work fell into four…

Adults Studying Pure Mathematics in Adult Tertiary Preparation.

Science.gov (United States)

Bennison, Anne

2002-01-01

Investigated the experiences of a group of adults enrolled in the Pure Mathematics module of the Certificate IV in Adult Tertiary Preparation in 2000 at one of the Institutes of TAFE in Brisbane, Australia. Classroom learning experiences, exposure to technology, and the impact of returning to study on other facets of students' lives were…

Mathematics Teachers at Work: Connecting Curriculum Materials and Classroom Instruction. Studies in Mathematical Thinking and Learning Series

Science.gov (United States)

Remillard, Janine T., Ed.; Herbel-Eisenmann, Beth A., Ed.; Lloyd, Gwendolyn M., Ed.

2011-01-01

This book compiles and synthesizes existing research on teachers' use of mathematics curriculum materials and the impact of curriculum materials on teaching and teachers, with a particular emphasis on--but not restricted to--those materials developed in the 1990s in response to the NCTM's Principles and Standards for School Mathematics. Despite…

Relationships between Mathematics Teacher Preparation and Graduates' Analyses of Classroom Teaching

Science.gov (United States)

Hiebert, James; Berk, Dawn; Miller, Emily

2017-01-01

The purpose of this longitudinal study was to investigate the relationships between mathematics teacher preparation and graduates' analyses of classroom teaching. Fifty-three graduates from an elementary teacher preparation program completed 4 video-based, analysis-of-teaching tasks in the semester before graduation and then in each of the 3…

The influence of instructional materials on mathematics achievement ...

African Journals Online (AJOL)

The influence of instructional materials on mathematics achievement of senior secondary students in Akamkpa Local Government Area of Cross River State, ... the ten public secondary schools in Akamkpa Local Government Area by stratified random technique, and two (2) Mathematics teachers per school for the study.

LOGICAL-ORIENTED TASKS AS A FORM OF ORGANIZATION OF THE EDUCATIONAL MATERIAL CONTENT IN TEACHING MATHEMATICS TO STUDENTS

Directory of Open Access Journals (Sweden)

Oksana Smirnova

2015-09-01

Full Text Available The article substantiates the need to improve the logical preparation of students. The authors regard the logical-oriented tasks as a form of organization of the content of educational material in teaching Mathematics and discriminate the types of tasks aimed at the formation of logical methods and operations.

SUBJECT «NUMBER SYSTEMS» IN TWO-LEVELED FORMAT PREPARATION TEACHERS OF MATHEMATICS

Directory of Open Access Journals (Sweden)

V. I. Igoshin

2017-01-01

Full Text Available The aim of this article is to analyze the format of a two-leveled training – bachelor and master – future teachers of mathematics from the point of view of the content of mathematical material, which is to develop prospective teachers of mathematics at those two levels, shaping their professional competence.Methods. The study involves the theoretical methods: the analysis of pedagogical and methodical literature, normative documents; historical, comparative and logical analysis of the content of pedagogical mathematical education; forecasting, planning and designing of two-leveled methodical system of training of future teachers of mathematics.Results and scientific novelty. The level differentiation of the higher education system requires developing the appropriate curricula for undergraduate and graduate programs. The fundamental principle must be the principle of continuity – the magister must continue to deepen and broaden knowledge and skills, along with competences acquired, developed and formed on the undergraduate level. From these positions, this paper examines the course «Number Systems» – the most important in terms of methodology course for future mathematics teachers, and shows what content should be filled with this course at the undergraduate level and the graduate level. At the undergraduate level it is proposed to study classical number systems – natural, integer, rational, real and complex. Further extensions of the number systems are studied at the graduate level. The theory of numeric systems is presented as a theory of algebraic systems, arising at the intersection of algebra and mathematical logic. Here we study algebras over a field, division algebra over a field, an alternative algebra with division over the field, Jordan algebra, Lie algebra. Comprehension of bases of the theory of algebras by the master of the «mathematical education» profile will promote more conscious

Improving the Mathematics Preparation of Elementary Teachers, One Lesson at a Time

Science.gov (United States)

Berk, Dawn; Hiebert, James

2009-01-01

In this paper, we describe a model for systematically improving the mathematics preparation of elementary teachers, one lesson at a time. We begin by identifying a serious obstacle for teacher educators: the absence of mechanisms for developing a shareable knowledge base for teacher preparation. We propose our model as a way to address this…

Effects of Teacher Preparation Courses: Do Graduates Use What They Learned to Plan Mathematics Lessons?

Science.gov (United States)

Morris, Anne K.; Hiebert, James

2017-01-01

We investigated whether the content pre-service teachers studied in elementary teacher preparation mathematics courses was related to their performance on a mathematics lesson planning task 2 and 3 years after graduation. The relevant mathematics knowledge was studied when the teachers were freshmen, 5 to 6 years earlier. Results showed that when…

Prepare 2 Learn: A mathematics intervention program for students at risk in Years 3 to 6 designed to help them reach expected level and become confident, responsible, independent mathematics learners

OpenAIRE

BERNADETTE MARY LONG

2017-01-01

This study reports on an intervention, Prepare 2 Learn, designed taking into account research literature and components of other successful mathematics programs. The research targeted students approximately 6 months behind the expected mathematics level for their year. The intervention consisted of four key components: building prerequisite knowledge of mathematical language, concepts, and skills to prepare students for their classroom mathematics; increasing fluency with mental computation; ...

Fostering Students' Preparation and Achievement in Upper Level Mathematics Courses

Science.gov (United States)

Celik, Mehmet; Shaqlaih, Ali

2017-01-01

This study describes an intervention to address both motivation, student engagement and preparation in upper-level mathematics courses. The effect of the intervention regarding students' achievements is investigated via students' opinions and data analysis from students' assessments. The results of this study show the featured intervention…

Should I take Further Mathematics? Physics undergraduates’ experiences of post-compulsory Mathematics

Science.gov (United States)

Bowyer, Jessica; Darlington, Ellie

2017-01-01

It is essential that physics undergraduates are appropriately prepared for the mathematical demands of their course. This study investigated physics students’ perceptions of post-compulsory mathematics as preparation for their degree course. 494 physics undergraduates responded to an online questionnaire about their experiences of A-level Mathematics and Further Mathematics. The findings suggest that physics undergraduates would benefit from studying Further Mathematics and specialising in mechanics during their A-level studies. As both A-level Mathematics and Further Mathematics are being reformed, universities should look closely at the benefits of Further Mathematics as preparation for their physics courses and either increase their admissions requirements, or recommend that students take Further Mathematics.

Pre-college Mathematics *Optional subject

OpenAIRE

ISHIDA, Yukio

2015-01-01

This course is a companion course to Calculus I. It aims to help students with little or no precalculus knowledge to master the basic calculus material in preparation for the more advanced course of Calculus I. This is done by reviewing high school mathematics.

Students' Views of A-Level Mathematics as Preparation for Degree-Level Economics

Science.gov (United States)

Darlington, Ellie; Bowyer, Jessica

2017-01-01

As part of a large-scale survey of over 4000 undergraduates at British universities, 238 economics students reported on their experiences of studying post-compulsory secondary mathematics qualifications (A-levels) and the preparation they provided for their degrees. Participants were positive about their experience of post-compulsory mathematics…

Generating a Networked Improvement Community to Improve Secondary Mathematics Teacher Preparation: Network Leadership, Organization, and Operation

Science.gov (United States)

Martin, W. Gary; Gobstein, Howard

2015-01-01

The Mathematics Teacher Education Partnership (MTE-Partnership) was formed to address the undersupply of new secondary mathematics teachers who are well prepared to help their students attain the goals of the Common Core State Standards and other college- and career-ready standards. This national consortium of more than 90 universities and 100…

Preparation of plant-specific NDA reference material

International Nuclear Information System (INIS)

Abedin-Zadeh, R.; Beetle, T.; Kuhn, E.; Terrey, D.; Turel, S.; Busca, G.; Guardini, S.

1983-01-01

The importance of having suitable and well characterized non-destructive assay (NDA) reference materials for the verification activities of the safeguards control authorities is stressed. The Euratom Inspectorate and the IAEA have initiated an extensive programme for the procurement and preparation of Joint Euratom/IAEA safeguards NDA reference materials with the active participation of the Ispra Establishment of the Euratom Joint Research Centre. The different type and nature of materials, condition of measurements, and plant characteristics and provisions had to be taken into account for plant-specific NDA reference materials. The preparation of each reference material was planned case by case and specific criteria such as limitations in different facilities, measurement capabilities, conditions, product availability and population variability are being ascertained. A procurement scheme was prepared describing step-by-step procedures detailing responsibilities, measurement conditions, destructive analysis schemes, desired characteristics and methods of data evaluation. This paper describes the principles and procedures carried out for the preparation of a reference MOX pin, low enriched uranium reference rods, low enriched uranium reference drums, reference MTR assemblies, and THTR reference pebbles. The scheme for each characterization technique is presented. (author)

A Paradigm for EST Materials Preparation.

Science.gov (United States)

Carreon, Edwina S.; Balarbar, Corazon V.

In many countries, suitable English for special purposes (ESP) textbooks and materials are difficult to find. ESP teachers and program coordinators often must develop their own materials, but preparing such materials requires training. One model that has served as a guide to numerous ESP materials projects is the Hutchinson and Waters' model. This…

Development of Contextual Mathematics teaching Material integrated related sciences and realistic for students grade xi senior high school

Science.gov (United States)

Helma, H.; Mirna, M.; Edizon, E.

2018-04-01

Mathematics is often applied in physics, chemistry, economics, engineering, and others. Besides that, mathematics is also used in everyday life. Learning mathematics in school should be associated with other sciences and everyday life. In this way, the learning of mathematics is more realstic, interesting, and meaningful. Needs analysis shows that required contextual mathematics teaching materials integrated related sciences and realistic on learning mathematics. The purpose of research is to produce a valid and practical contextual mathematics teaching material integrated related sciences and realistic. This research is development research. The result of this research is a valid and practical contextual mathematics teaching material integrated related sciences and realistic produced

Remarks on the mathematical description of materials damage by irradiation

International Nuclear Information System (INIS)

Steinbach, E.

1987-01-01

In describing radiation damage processes in materials, the chemical rate theory proves to be the most effective mathematical method. The applicability, and even the validity, of this theory, which has been successfully applied in many other scientific fields, have been questioned by some authors. After rigorous mathematical analysis of the relevant rate equations and the corresponding self-consistent calculation of sink strengths, the main criticisms on this subject can be disproved

Strategies to Support PGCE Mathematics and Science Students Preparing for Assignments at Masters Level

OpenAIRE

Tas, Maarten; Forsythe, Sue

2010-01-01

The main aim of this study was to analyse and evaluate the effectiveness of support strategies being put into place for students who need to write assignments at Masters Level. In preparation for writing a 5000 word assignment on an aspect of teaching Mathematics or Science, 57 Science and Mathematics PGCE students were asked to write a 500 word synopsis which included an introduction, description of the main focus, questions that the assignment would address and possible strategies for teach...

How does the high school mathematics teacher prepares the learning process based on the 2013 curriculum 2017 revision

Science.gov (United States)

Latif, I. A.; Saputro, D. R. S.; Riyadi

2018-03-01

2013 Curriculum (K13) provides an opportunity for students to develop the potential attitudes, knowledge, and skills necessary for life and society and contribute to the welfare of human life. The K13 2017 revision requires teachers to integrate 21st-century skills in the learning process. They are consist of critical thinking and problem-solving, communication, creativity and innovation, and collaboration (4C skills), Higher Order Thinking Skills (HOTS), literacy movement, and character education. This study is a qualitative research that aims to describe the steps performed by a high school mathematics teacher in preparing the Lesson Plan (RPP) in accordance with K13 2017 revision. The subject of this study is a Civil Servant Mathematics teacher at SMAN 1 Wuryantoro, Wonogiri Regency. This study used interview method with time triangulation technique to obtain valid data. Based on the interviews it is concluded that in preparing the RPP in accordance with K13 revision 2017, the teacher is guided by The Minister of Education and Culture Regulation (Permendikbud) Number 22 of 2016 and Pedoman Penyusunan RPP Abad 21. The first step taken by the teacher in preparing and developing RPP is quoting KI from Permendikbud Number 21 2016 and KD from Permendikbud Number 24 of 2016. After that, teacher formulates Indicators of Competency Achievement (IPK) in accordance with KD, learning objectives in accordance with IPK, learning materials in accordance with IPK, learning activities integrating 21st-century skills and in line with learning objectives, learning assessment instruments, and learning reflection activities.

Mathematical analysis II

CERN Document Server

Canuto, Claudio

2015-01-01

The purpose of the volume is to provide a support textbook for a second lecture course on Mathematical Analysis. The contents are organised to suit, in particular, students of Engineering, Computer Science and Physics, all areas in which mathematical tools play a crucial role. The basic notions and methods concerning integral and differential calculus for multivariable functions, series of functions and ordinary differential equations are presented in a manner that elicits critical reading and prompts a hands-on approach to concrete applications. The pedagogical layout echoes the one used in the companion text Mathematical Analysis I. The book’s structure has a specifically-designed modular nature, which allows for great flexibility in the preparation of a lecture course on Mathematical Analysis. The style privileges clarity in the exposition and a linear progression through the theory. The material is organised on two levels. The first, reflected in this book, allows students to grasp the essential ideas, ...

A mathematical model in charactering chloride diffusivity in unsaturated cementitious material

NARCIS (Netherlands)

Zhang, Y.; Ye, G.; Pecur, I.B.; Baricevic, A.; Stirmer, N; Bjegovic, D.

2017-01-01

In this paper, a new analytic model for predicting chloride diffusivity in unsaturated cementitious materials is developed based on conductivity theory and Nernst-Einstein equation. The model specifies that chloride diffusivity in unsaturated cementitious materials can be mathematically described as

Preparation of porous materials for radionuclides capture

International Nuclear Information System (INIS)

Bajzikova, Anna; Smrcek, Stanislav; Kozempel, Jan; Vlk, Martin; Barta, Jan

2015-01-01

Porous materials showing promise for radionuclide capture from water at contaminated sites were prepared. Nanoporous materials (size of pores 1-100 nm) and some polymers are well suited to this purpose owing their affinity for selected radionuclides. Nanoporous metal oxides and silica gel with styrene-divinylbenzene-TODGA-modified surface were prepared, characterized and tested for radionuclide ( 227 Ac, 227 Th, 223 Ra) capture efficiency. (orig.)

A Capstone Mathematics Course for Prospective Secondary Mathematics Teachers

Science.gov (United States)

Artzt, Alice F.; Sultan, Alan; Curcio, Frances R.; Gurl, Theresa

2012-01-01

This article describes an innovative capstone mathematics course that links college mathematics with school mathematics and pedagogy. It describes how college juniors in a secondary mathematics teacher preparation program engage in leadership experiences that enable them to learn mathematics for teaching while developing student-centered…

Preparing Tomorrow's Teachers: Are New Mexico's Education School Graduates Ready to Teach Reading and Mathematics in Elementary Classrooms?

Science.gov (United States)

Greenberg, Julie; Jacobs, Sandi

2009-01-01

As a follow up to National Council on Teacher Quality (NCTQ's) national studies of how well elementary teachers are prepared to teach reading and mathematics, NCTQ looks at preparation in both subjects in all undergraduate teacher preparation programs in New Mexico. This analysis evaluated New Mexico's eight undergraduate elementary teacher…

Mathematics for physical chemistry

CERN Document Server

Mortimer, Robert G

2005-01-01

Mathematics for Physical Chemistry, Third Edition, is the ideal text for students and physical chemists who want to sharpen their mathematics skills. It can help prepare the reader for an undergraduate course, serve as a supplementary text for use during a course, or serve as a reference for graduate students and practicing chemists. The text concentrates on applications instead of theory, and, although the emphasis is on physical chemistry, it can also be useful in general chemistry courses. The Third Edition includes new exercises in each chapter that provide practice in a technique immediately after discussion or example and encourage self-study. The first ten chapters are constructed around a sequence of mathematical topics, with a gradual progression into more advanced material. The final chapter discusses mathematical topics needed in the analysis of experimental data.* Numerous examples and problems interspersed throughout the presentations * Each extensive chapter contains a preview, objectives, and ...

Efforts to Improve Mathematics Teacher Competency Through Training Program on Design Olympiad Mathematics Problems Based on Higher Order Thinking Skills in The Junior High School

Science.gov (United States)

Arnellis, A.; Jamaan, E. Z.; Amalita, N.

2018-04-01

The goal to analyse a improvement of teacher competence after being trained in preparing high-order math olympicad based on high order thinking skills in junior high school teachers in Pesisir Selatan Regency. The sample of these activities are teachers at the MGMP junior high school in Pesisir Selatan District. Evaluation of the implementation is done by giving a pre test and post test, which will measure the success rate of the implementation of this activities. The existence of the devotion activities is expected to understand the enrichment of mathematics olympiad material and training in the preparation of math olympiad questions for the teachers of South Pesisir district junior high school, motivating and raising the interest of the participants in order to follow the mathematics olympiad with the enrichment of mathematics materials and the training of problem solving about mathematics olympiad for junior high school teachers, the participants gain experience and gain insight, as well as the ins and outs of junior mathematics olympiad and implement to teachers and students in olympic competitions. The result of that the post-test is better than the result of pretest in the training of mathematics teacher competence improvement in composing the mathematics olympiad problem based on high order thinking skills of junior high school (SMP) in Pesisir Selatan District, West Sumatra, Indonesia.

Influences on Mathematical Preparation of Secondary School Teachers of Mathematics.

Science.gov (United States)

Johnson, Carl S.; Byars, Jackson A.

The results of a survey related to the impact of various recommendations on preservice content programs for teachers of mathematics are reported. The content of current programs is compared to the recommendations of the Committee on Undergraduate Programs in Mathematics (CUPM). The acceptance of CUPM and the Cambridge Conference on School…

An Investigation of the Teaching Approach Used by Tutors to Prepare Science and Mathematics Teachers during Training at Morogoro Teachers' College

Science.gov (United States)

Mungure, Daudi Mika

2017-01-01

This paper investigated the teaching approach used by tutors to prepare science and mathematics teachers during training at Morogoro teachers' college. For six years consecutive the performance of science and mathematics in secondary school has become very poor even though the training colleges produce science and mathematics teachers every year…

Mathematization in introductory physics

Science.gov (United States)

Brahmia, Suzanne M.

Mathematization is central to STEM disciplines as a cornerstone of the quantitative reasoning that characterizes these fields. Introductory physics is required for most STEM majors in part so that students develop expert-like mathematization. This dissertation describes coordinated research and curriculum development for strengthening mathematization in introductory physics; it blends scholarship in physics and mathematics education in the form of three papers. The first paper explores mathematization in the context of physics, and makes an original contribution to the measurement of physics students' struggle to mathematize. Instructors naturally assume students have a conceptual mastery of algebra before embarking on a college physics course because these students are enrolled in math courses beyond algebra. This paper provides evidence that refutes the validity of this assumption and categorizes some of the barriers students commonly encounter with quantification and representing ideas symbolically. The second paper develops a model of instruction that can help students progress from their starting points to their instructor's desired endpoints. Instructors recognize that the introductory physics course introduces new ideas at an astonishing rate. More than most physicists realize, however, the way that mathematics is used in the course is foreign to a large portion of class. This paper puts forth an instructional model that can move all students toward better quantitative and physical reasoning, despite the substantial variability of those students' initial states. The third paper describes the design and testing of curricular materials that foster mathematical creativity to prepare students to better understand physics reasoning. Few students enter introductory physics with experience generating equations in response to specific challenges involving unfamiliar quantities and units, yet this generative use of mathematics is typical of the thinking involved in

Preparation of fish material for interlaboratory study on PFCs

NARCIS (Netherlands)

Korytar, P.; Kwadijk, C.J.A.F.; Lohman, M.; Barneveld, van E.

2007-01-01

The Institute for Environmental Studies, Vrije Universiteit (IVM) has requested Wageningen IMARES for the preparation of fish material for use in interDlaboratory performance study on analysis of perfluorinated compounds (PFCs). It was requested that the material should be prepared from fillet of

Engineering Mathematics I : Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering

CERN Document Server

Rančić, Milica

2016-01-01

This book highlights the latest advances in engineering mathematics with a main focus on the mathematical models, structures, concepts, problems and computational methods and algorithms most relevant for applications in modern technologies and engineering. In particular, it features mathematical methods and models of applied analysis, probability theory, differential equations, tensor analysis and computational modelling used in applications to important problems concerning electromagnetics, antenna technologies, fluid dynamics, material and continuum physics and financial engineering. The individual chapters cover both theory and applications, and include a wealth of figures, schemes, algorithms, tables and results of data analysis and simulation. Presenting new methods and results, reviews of cutting-edge research, and open problems for future research, they equip readers to develop new mathematical methods and concepts of their own, and to further compare and analyse the methods and results discussed. The ...

Nonconvex Model of Material Growth: Mathematical Theory

Science.gov (United States)

Ganghoffer, J. F.; Plotnikov, P. I.; Sokolowski, J.

2018-06-01

The model of volumetric material growth is introduced in the framework of finite elasticity. The new results obtained for the model are presented with complete proofs. The state variables include the deformations, temperature and the growth factor matrix function. The existence of global in time solutions for the quasistatic deformations boundary value problem coupled with the energy balance and the evolution of the growth factor is shown. The mathematical results can be applied to a wide class of growth models in mechanics and biology.

Teacher's Ability to Develop Learning Materials Potentially Mathematical Discourse

Directory of Open Access Journals (Sweden)

Hamdani Hamdani

2017-10-01

Full Text Available In the process of learning in the field, the teacher still dominates the conversation while the students as a passive listener. As a result, not only the communication skills of students who are less developed, the understanding of student material is also lacking. Therefore it is necessary to research the ability of teachers in developing learning tools potentially mathematical discourse to improve students' mathematical communication skills. The research method used is descriptive. Research activities include: identification of problems through questionnaires, observation, and interviews; teacher training; teachers develop learning tools; validation; and enhancement of the device by the teacher. The subject of this research is the junior high school mathematics teacher from several districts in the border area of Sambas-Sarawak Regency. The results show that in every learning mathematics there is always a conversation between teachers and students, but rarely use the question "why" and "how". Most teacher-made lesson plans contain scenarios of conversations between teachers and students, but just plain questioning, have not led to a debate between each other so that understanding becomes deeper. Student worksheet made by the teacher in the form of a matter of the ordinary story, rarely load non-routine problem let alone open-ended.

A REFINED MATHEMATICAL MODEL OF MULTIPHYSICS PROCESSES FOR MAGNETIC PULSE TREATMENT OF MATERIALS

Directory of Open Access Journals (Sweden)

E.I. Baida

2015-04-01

Full Text Available Introduction. The complexity of the theoretical description of the magnetic pulse treatment of the material is in the mutual coupled processes of electromagnetic and thermal fields with plastic deformation of the material and processes in an electrical circuit. The paper deals with the combined transient mathematical model of the system of equations of the electromagnetic field, theory of elasticity, thermal conductivity and electrical circuit. Purpose. Research and testing of the developed mathematical model and assess the impact of various parameters on the process of deformation of the work piece. Methodology. Investigation of nonlinear mathematical model is carried out by the finite element method using a special software package. Results. The resulting solution of the transient mathematical model allows studying the influence of parameters of the circuit, the speed and the characteristics of the material to plastic deformation and heating of the work piece, which allows to select the optimum process parameters. Originality. This is an integrated approach to the development of a mathematical model, which includes the electromagnetic field equations, the theory of elasticity, thermal conductivity and electrical circuit equations with a storage capacitor. Conclusions. A comprehensive mathematical model and its solution are obtained. It is established a small effect of heating temperature on the amount of strain. Currents caused by movement of the work piece must be taken into account in the calculations. Inertial forces significantly affect the nature of the deformation. During the deformation it is necessary to consider the nonlinearity of elasticity modulus. Thermal deformation of the work piece is much less mechanical strain and opposite in sign to them, but the surface temperature stresses due to the high temperature gradient equal to 20 % of the yield strength of the work piece.

Manipulatives Implementation For Supporting Learning Of Mathematics For Prospective Teachers

Science.gov (United States)

Sulistyaningsih, D.; Mawarsari, V. D.; Hidayah, I.; Dwijanto

2017-04-01

Manipulatives are needed by teachers to facilitate students understand of mathematics which is abstract. As a prospective mathematics teacher, the student must have good skills in making manipulatives. Aims of this study is to describe the implementation of learning courses of manipulative workshop in mathematics education courses by lecturer at Universitas Muhammadiyah Semarang which includes the preparation of learning, general professional ability, the professional capacity specifically, ability of self-development, development class managing, planning and implementation of learning, a way of delivering the material, and evaluation of learning outcomes. Data collection techniques used were questionnaires, interviews, and observation. The research instrument consisted of a questionnaire sheet, sheet observation and interview guides. Validity is determined using data triangulation and triangulation methods. Data were analyzed using an interactive model. The results showed that the average value of activities in preparation for learning, fosters capabilities of general professional, specialized professional, self-development, manage the classroom, implementing the learning, how to deliver the material, and how to evaluate learning outcomes are 79%, 73%, 67%, 75%, 83%, 72%, 64%, and 54%, respectively

An introduction to the mathematical theory of dynamic materials

CERN Document Server

Lurie, Konstantin A

2017-01-01

Mathematical treatment to properties of dynamic materials, material substances whose properties are variable in space and time are examined in this book. This new edition emphasizes the differences between material optimization techniques in statics and dynamics. Systems with one spatial coordinate and time are used to illustrate essentials of temporal property change in this setting and prompt forthcoming extensions and technical improvements. Since the release of the first edition, a number of new results have created a more complete picture of unusual effects hidden in spatio-temporal material geometry. This renewed look has revealed a conceptually new mechanism of relaxation of material optimization problems in dynamics, which has led to additional resources for optimization previously concealed in the property layouts. Dynamic materials are studied in this book from the following perspectives: ability to appear in dissimilar implementations, universality as formations that are thermodynamically open, and...

Meeting in mathematics

DEFF Research Database (Denmark)

Mogensen, Arne; Georgiev, Vladimir; Ulovec, Andreas

To encourage many more young people to appreciate the real nature and spirit of mathematics and possibly to be enrolled in mathematics study it is important to involve them in doing mathematics (not just learning about mathematics). This goal could be achieved if mathematics teachers are prepared...... to identify and work with mathematically gifted students (without loosing the rest). The book offers chapters on gifted students, mathematical competences and other issues....

The mathematical model accuracy estimation of the oil storage tank foundation soil moistening

Science.gov (United States)

Gildebrandt, M. I.; Ivanov, R. N.; Gruzin, AV; Antropova, L. B.; Kononov, S. A.

2018-04-01

The oil storage tanks foundations preparation technologies improvement is the relevant objective which achievement will make possible to reduce the material costs and spent time for the foundation preparing while providing the required operational reliability. The laboratory research revealed the nature of sandy soil layer watering with a given amount of water. The obtained data made possible developing the sandy soil layer moistening mathematical model. The performed estimation of the oil storage tank foundation soil moistening mathematical model accuracy showed the experimental and theoretical results acceptable convergence.

Preparation of pure TiO2 sorption material

International Nuclear Information System (INIS)

Špendlíková, Irena; Raindl, Jakub; Němec, Mojmír

2013-01-01

Among the natural or anthropogenic radionuclides of very low concentrations nowadays measured in environmental samples, the radionuclide of 236 U has been recently included. In these ultra-trace analyses, the purity of sorption materials is very important and the traditional preparation procedures have to be optimized to minimize possible contamination. In the case of the determination of natural concentration of 236 U ( 236 U/ 238 U ∼ 10 -10 - 10 -14 ), the sample treatment procedure has to be modified in order to eliminate possible contamination from anthropogenic 236 U that may result even in more than ten thousand times higher 236 U/ 238 U ratios. Many inorganic and organic materials have been proposed for the extraction of uranium. However, only several of them are suitable for the uranium sorption from the solutions of low uranium concentration, but relatively high salt content, such as fresh water, sea water etc. At the same time they have to meet other limiting parameters such as fast kinetics, chemical stability, and low costs. Among the inorganic sorption materials, titanium dioxide has been studied for years with promising results. Titanium dioxides can be prepared via the hydrolysis of titanium compounds, either inorganic salts or organic derivatives, but their properties strongly depend on the preparation conditions. In classical procedures, titanium dioxides are prepared from commercial inorganic salts, such as sulphates or chlorides, or even from industrial intermediates of the titanium white production. Typically, the resulting titanium dioxides are contaminated with uranium already from the origin. Assuming that most organic compounds do not contain uranium and that it is possible to find 'uranium free' water, titanium dioxide free of uranium contamination could be prepared by the hydrolysis of organic titanium derivatives. The aim of this study was to find a suitable way of pure titanium dioxide preparation and to optimize the preparation

Developing Teaching Material Based on Realistic Mathematics Andoriented to the Mathematical Reasoning and Mathematical Communication

OpenAIRE

Habsah, Fitria

2017-01-01

This research aims to produce mathematics textbook for grade VII junior high school students based on realistic mathematics and oriented to the mathematical reasoning and mathematical communication. The quality is determined based on Nieveen criteria, including validity, practicality, and effectiveness.This study was a research and development and used Borg & Gall model. The subject of this research were the students of SMPN 2 Pujon-Kabupaten Malang, that is 30 students in an experimental cla...

New materials for sample preparation techniques in bioanalysis.

Science.gov (United States)

Nazario, Carlos Eduardo Domingues; Fumes, Bruno Henrique; da Silva, Meire Ribeiro; Lanças, Fernando Mauro

2017-02-01

The analysis of biological samples is a complex and difficult task owing to two basic and complementary issues: the high complexity of most biological matrices and the need to determine minute quantities of active substances and contaminants in such complex sample. To succeed in this endeavor samples are usually subject to three steps of a comprehensive analytical methodological approach: sample preparation, analytes isolation (usually utilizing a chromatographic technique) and qualitative/quantitative analysis (usually with the aid of mass spectrometric tools). Owing to the complex nature of bio-samples, and the very low concentration of the target analytes to be determined, selective sample preparation techniques is mandatory in order to overcome the difficulties imposed by these two constraints. During the last decade new chemical synthesis approaches has been developed and optimized, such as sol-gel and molecularly imprinting technologies, allowing the preparation of novel materials for sample preparation including graphene and derivatives, magnetic materials, ionic liquids, molecularly imprinted polymers, and much more. In this contribution we will review these novel techniques and materials, as well as their application to the bioanalysis niche. Copyright © 2016 Elsevier B.V. All rights reserved.

New preparation of fish material for interlaboratory study on PFCs

NARCIS (Netherlands)

Korytar, P.; Lohman, M.; Kwadijk, C.J.A.F.; Barneveld, van E.

2007-01-01

The Institute for Environmental Studies, Vrije Universiteit (IVM) has requested Wageningen IMARES to prepare a new fish material for use in the interlaboratory performance study on analysis of perfluorinated compounds (PFCs) due to the low amount of contaminants in the previously prepared material.

Preparation of working calibration and test materials: uranyl nitrate solution

International Nuclear Information System (INIS)

Yamamura, S.S.; Spraktes, F.W.; Baldwin, J.M.; Hand, R.L.; Lash, R.P.

1977-05-01

Reliable working calibration and test materials (WCTMs) are essential to a meaningful analytical measurements quality assurance program. This report describes recommended methods for the preparation of uranyl nitrate solution WCTMs for testing analytical methods, for calibrating methods, and for testing personnel. Uranyl nitrate solution WCTMs can be synthesized from characterized starting materials or prepared from typical plant materials by thorough characterization with reference to primary or secondary reference calibration and test materials (PRCTMs or SRCTMs). Recommended starting materials are described along with detailed procedures for (a) preparing several widely-used types of uranyl nitrate solution WCTMs, (b) packaging the WCTMs, (c) analyzing the WCTMs to establish the reference values or to confirm the synthesis, and (d) statistically evaluating the analytical data to assign reference values and to assess the accuracy of the WCTMs

Mathematical models of hydrocyclone performance in various copper ores preparation circuits

Directory of Open Access Journals (Sweden)

Niedoba Tomasz

2016-01-01

Full Text Available Copper ores located in the Lubin-Glogow Copper Basin contain three main lithological fractions: sandstone, carbonate and shale. This fact is the basic problem of organization and conducting ore preparation to flotation. The existing circuit of feed preparation contains (in ZG Rudna five classification nodes of hydrocyclones which fit for various purposes. The elaboration of concept of monitoring work of these nodes should be based on appropriate mathematical models of process. It was decided that either regressive or non-dimensional models that is classification according to Svarovsky, and particularly Plitt’s, will be suitable, in the aspects of d50 and partition sharpness. Errors resulting from determination of the features being part of the equations were also important. In this paper the errors were divided into technical and technological. The issue of experiments organization (mineralogical investigation connected with each classification node was also addressed. It is obvious that each classification node must obtain its characteristics because of various comminution products directed to classification.

Preparation and characterization of the fish reference material

International Nuclear Information System (INIS)

Ulrich, Joao Cristiano

2011-01-01

The certified reference materials (CRMs) play an important role in obtaining measurement results traceable to the International System of Units, through an unbroken chain of comparisons. Thus, the demand for new certified reference materials (CRMs) increases every day in all areas of knowledge. The availability of reference materials, mainly in Brazil is still incipient, given that the demand far exceeds the available variety of these materials. The amount of certified reference materials available in the country is insufficient to meet the need of the scientific community and demands for development of new methodologies. Among the many areas in need of reference materials, we highlight the importance for the food trade balance for these products within the country. The certification of food products, intended both for export and for domestic consumption, requires analysis methods that provide precise and accurate results to ensure product quality. This paper describes the preparation and certification of a reference material in the fish matrix in mercury and methylmercury. The study brings together since the stage of material selection, preparation, development of homogeneity and stability studies and characterization. The certification was performed by means of measurements using two analytical techniques, flow injection analysis - cold vapor atomic absorption spectrometry (FIA-CV-AAS) and isotope dilution applied to mass spectrometry (IDMS), which is a primary method. In this work the standards of the ISO 30 (ABNT 30-34) and ISO Guide 35 was used as the basis for the preparation and characterization of the material. For the calculation of uncertainties was used the GUM and Eurachem guide. As a result, was produced and certified a lot of material in relation to the concentration of mercury (Hg = 0.271 ± 0.057 mg g -1 ) and methylmercury (MeHg = 0.245 ± 0.038 mg g -1 ), and informational values of lead and arsenic. (author)

Preparation of ceramic materials for surface characterization

International Nuclear Information System (INIS)

Zipperian, D.C.

1989-01-01

This paper discusses how microstructural preparation permits a microscopic analysis of a material's internal structure, which is related to the physical properties of the material. Today, numerous microstructural quantitative and qualitative measurements are commonly utilized. Several of these include phase determination, phase hardness, phase distribution, grain size and shape, and porosity and size distribution. The most widely used surface characterization techniques are optical microscopy, electron microscopy, and x-ray microscopy. Optical microscopy includes both transmitted-and reflected-light techniques and requires a surface preparation prior to analysis. Transmitted-light microscopy samples require thinning and polishing of both sides of the sample, whereas reflected light techniques require polishing of only one side of the sample

Preparation and evaluation of reference materials for accountancy analysis. (1) Preparation and evaluation method

International Nuclear Information System (INIS)

Takamatsu, Mai; Kacchi, Tomokazu; Murakami, Toshiki; Ai, Hironobu; Sumi, Mika; Abe, Katsuo; Kageyama, Tomio; Nakazawa, Hiroaki

2009-01-01

Isotope dilution mass spectrometry method used for the accountancy analysis at nuclear fuel facilities requires the standard materials called LSD (Large Size Dried) spike. Generally, LSD spikes are prepared from certified reference materials (CRMs) which supplied from foreign laboratories. However, the difficulty of Pu CRM importation is increasing. It is important for safeguards to attain and continue high reliable accountancy analysis and stable securing of LSD spike is essential. Therefore, in order to conserve CRMs, several types of LSD spike were prepared under collaboration work between JAEA and JNFL, such as the amount of nuclear material in one LSD spike is decreased and others. Practical test with actual samples were performed at JNFL Rokkasho reprocessing plant, and those results were compared with the results obtained by using LSD spike which supplied from foreign laboratory. Preparation and verification analysis of LSD spikes and evaluation of uncertainty based on ISO-GUM will be presented. (author)

Development of an Openmath Content Dictionary for Mathematical Knowledge of Materials Science and Engineering

Directory of Open Access Journals (Sweden)

Toshihiro Ashino

2012-12-01

Full Text Available Many relationships between parameters and physical properties in materials science and engineering are represented as mathematical expressions, such as empirical equations and regression expressions. Some materials databases handle such information with indirect methods: as a table of sets of parameters, as a list of statements of programming languages, and other ways. There is no standardized way to represent mathematical relationships, and that makes it difficult to exchange, process, and display such information. The AIST (National Institute of Advanced Industrial Science and Technology in Japan thermophysical property database manages sets of parameter values for expressions and Fortran statements that represent relationships between physical parameters, e.g., temperature, pressure, etc. and thermophysical properties. However, in this method, it is not easy to add new parameters, to process expressions, and exchange information with other software tools. In this paper, we describe the current implementation of representing mathematical knowledge in the AIST thermophysical property database, and we also discuss its problems, sample implementations, and definitions of the OpenMath content dictionary for materials science and engineering.

Should I Take Further Mathematics? Physics Undergraduates' Experiences of Post-Compulsory Mathematics

Science.gov (United States)

Bowyer, Jessica; Darlington, Ellie

2017-01-01

It is essential that physics undergraduates are appropriately prepared for the mathematical demands of their course. This study investigated physics students' perceptions of post-compulsory mathematics as preparation for their degree course. 494 physics undergraduates responded to an online questionnaire about their experiences of A-level…

Mathematical modeling of the emission of heavy metals into water bodies from building materials derived from production waste

Directory of Open Access Journals (Sweden)

Pugin Konstantin Georgievich

2016-01-01

Full Text Available At the present time industrial waste is considered to be an alternative to primary natural resources when producing construction materials and products. The use of industrial waste in the construction branch allows reducing ecological load on the environment and population as a result of reducing the amount of unrecyclable waste and reducing the use of primary natural resources. Though when involving waste products as raw material in the preparation of building materials there occur environmental risks of anthropogenic impact increase on the environment. These risks are related to possible emission of heavy metals from construction materials in use. The article describes a tool which allows predicting this issue, depending on the acidity of the medium, the residence time of the material in the environment. The experimental data obtained in determining the migration activity of metals from cement concretes to aqueous solutions served as the basis for the mathematical model. The proposed model allows us to make a prediction of anthropogenic impact on the environment and commensurate this impact with the possibility of assimilation of the environment area where the building materials are applied. This will allow conducting an effective assessment of the created and applied technologies of waste disposal, taking into account the operating conditions of the materials produced.

Preparation of reference material for the measurement of natural radioactivity

International Nuclear Information System (INIS)

Ben Tekaya, Malik

2010-01-01

The objective of this work is to prepare reference material for the calibration of gamma spectrometry, alpha and XRF .Many procedures of chemical preparation and radiological analysis of a reference material from Triple Superphosphate were tested. Several techniques and methods of measurement were used. In addition to a description and validation of these procedures, a study of repeatability was conducted which resulted in a positive characterization of this material.

TEACHING MATHEMATICAL DISCIPLINES AT THE MEDICAL UNIVERSITY

Directory of Open Access Journals (Sweden)

V. Ya. Gelman

2018-01-01

Full Text Available Introduction.In programs of training of students of medical specialties, Mathematics is a subject of basic education, i.e. non-core discipline. However, studying Mathematics is extremely important for future physicians, as recently there has been an impetuous development of mathematization in the field of health care. Today, a set of the new medical devices, the equipment and high technologies are being developed based on the mathematical modeling, analysis and forecasting. Mathematical methods are widely applied to diagnostics, development of life-support systems and the description of various biological processes both at the molecular level,  and at the level of a whole organism, its systems, bodies and tissues. The solution of many medical tasks in the field of taxonomy, genetics, and organization of medical service is impossible without knowledge of mathematics. Unfortunately, along with the evident importance of mathematical preparation for a medical profession, its need is poorly realized not only by junior students, but even by some teachers of specialized departments of medical schools.The aim of the publication is to discuss the problems that arise in the teaching of mathematical disciplines to students at a medical school and to suggest possible solutions to these problems.Methodology and research methods. The study is based on the use of modeling of the educational process. The methods of analysis, generalization and the method of expert assessments were applied in the course of the research.Results and scientific novelty. The aspects of mathematical preparation at the university are considered on the basis of the application of the multiplicative model of training quality. It is shown that the main students’ learning difficulties in Mathematics are connected with the following factors: the initial level of mathematical preparation of students and their motivation; outdated methods of Mathematics teaching and academic content

Mathematical Tools for Discovery of Nanoporous Materials for Energy Applications

International Nuclear Information System (INIS)

Haranczyk, M; Martin, R L

2015-01-01

Porous materials such as zeolites and metal organic frameworks have been of growing importance as materials for energy-related applications such as CO 2 capture, hydrogen and methane storage, and catalysis. The current state-of-the-art molecular simulations allow for accurate in silico prediction of materials' properties but the computational cost of such calculations prohibits their application in the characterisation of very large sets of structures, which would be required to perform brute-force screening. Our work focuses on the development of novel methodologies to efficiently characterize and explore this complex materials space. In particular, we have been developing algorithms and tools for enumeration and characterisation of porous material databases as well as efficient screening approaches. Our methodology represents a ensemble of mathematical methods. We have used Voronoi tessellation-based techniques to enable high-throughput structure characterisation, statistical techniques to perform comparison and screening, and continuous optimisation to design materials. This article outlines our developments in material design

Learning by Preparing to Teach: Fostering Self-Regulatory Processes and Achievement during Complex Mathematics Problem Solving

Science.gov (United States)

Muis, Krista R.; Psaradellis, Cynthia; Chevrier, Marianne; Di Leo, Ivana; Lajoie, Susanne P.

2016-01-01

We developed an intervention based on the learning by teaching paradigm to foster self-regulatory processes and better learning outcomes during complex mathematics problem solving in a technology-rich learning environment. Seventy-eight elementary students were randomly assigned to 1 of 2 conditions: learning by preparing to teach, or learning for…

Mathematical modelling of the laser processing of compose materials

International Nuclear Information System (INIS)

Gromyko, G.F.; Matsuka, N.P.

2009-01-01

Expansion of the protective coating scope led to the necessity to work out lower priced methods of treatment of machine elements. Making of an adequate, agreed with process features, mathematical model and development of effective methods of its solving are promising directions in this fields. In this paper the mathematical model of high-temperature laser treatment via moving source of pre-sprayed with composite powder padding is developed. Presented model describes accurately enough the heat processes taking place by laser processing of machine elements. Varying input parameters of model (laser power, temperature and composition of environment, characteristics and quantitative composition of using materials, etc.) one can get a cheap tool of preliminary estimates for wide range of similar problems. Difference method, based on process physical features and taking into account main process-dependent parameters had been developed for solving of the built system of nonlinear equations. (authors)

Mathematical model for choosing the nuclear safe matrix compositions for fissile material immobilization

International Nuclear Information System (INIS)

Gorshtein, A.I.; Matyunin, Yu.I.; Poluehktov, P.P.

2000-01-01

A mathematical model is proposed for preliminary choice of the nuclear safe matrix compositions for fissile material immobilization. The IBM PC computer software for nuclear safe matrix composition calculations is developed. The limiting concentration of fissile materials in the some used and perspective nuclear safe matrix compositions for radioactive waste immobilization is calculated [ru

Mathematical models of physics problems (physics research and technology)

CERN Document Server

Anchordoqui, Luis Alfredo

2013-01-01

This textbook is intended to provide a foundation for a one-semester introductory course on the advanced mathematical methods that form the cornerstones of the hard sciences and engineering. The work is suitable for first year graduate or advanced undergraduate students in the fields of Physics, Astronomy and Engineering. This text therefore employs a condensed narrative sufficient to prepare graduate and advanced undergraduate students for the level of mathematics expected in more advanced graduate physics courses, without too much exposition on related but non-essential material. In contrast to the two semesters traditionally devoted to mathematical methods for physicists, the material in this book has been quite distilled, making it a suitable guide for a one-semester course. The assumption is that the student, once versed in the fundamentals, can master more esoteric aspects of these topics on his or her own if and when the need arises during the course of conducting research. The book focuses on two cor...

DISCRETE MATHEMATICS AS FUNDAMENTAL DISCIPLINE IS IN SYSTEM OF MATHEMATICAL PREPARATION OF FUTURE SOFTWARE ENGINEER

OpenAIRE

D. Shchedrolosev

2010-01-01

Fundamental mathematical background is an important part of training future engineers and programmers. The paper considers existing approaches to teaching the fundamentals of discrete mathematics specialist IT profile, a comparative analysis of modern textbooks on discrete mathematics for IT professionals was conducted

Preparation and certification of rice flour reference materials for trace elements analysis

International Nuclear Information System (INIS)

Cho, Kyung Haeng; Park, Chang Joon; Woo, Jin Choon; Suh, Jung Ki; Han, Myung Sub; Lee, Jong Hae

1998-01-01

Rice flour reference materials were prepared from the unpolished rice grown in korea and certified for elemental composition. The reference materials consist of two samples containing normal and high level. The reference material at elevated level was prepared by spiking to the normal rice flour six toxic elements of As, Cd, Cu, Cr, Hg, Pb with 1.0μg/g on a dry weight basis. Homogeneity of the prepared materials was evaluated through the determination of Ca, Cu, Fe, Mn, Zn by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). Small variance of elemental composition among inter-bottled samples assured homogeneity of the prepared materials. The materials were decomposed by high pres-sure digestion and microwave digestion method. INAA, AAS, inductively coupled plasma-atomic absorption spectrometry (ICP-AES), ICP-mass spectrometry (MS) and vapour generation techniques were employed to analyze the reference materials. From this independent analytical results, the certified or reference values are determined for As, Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, P, Pb, Se, Zn

DISCRETE MATHEMATICS AS FUNDAMENTAL DISCIPLINE IS IN SYSTEM OF MATHEMATICAL PREPARATION OF FUTURE SOFTWARE ENGINEER

Directory of Open Access Journals (Sweden)

D. Shchedrolosev

2010-04-01

Full Text Available Fundamental mathematical background is an important part of training future engineers and programmers. The paper considers existing approaches to teaching the fundamentals of discrete mathematics specialist IT profile, a comparative analysis of modern textbooks on discrete mathematics for IT professionals was conducted

Learning Environments in Mathematics

Science.gov (United States)

Turner, Vanshelle E.

2017-01-01

Learning mathematics is problematic for most primary school age children because mathematics is rote and the memorization of steps rather than an approach to seeing relationships that builds inquiry and understanding. Therefore, the traditional "algorithmic" way of teaching mathematics has not fully prepared students to be critical…

Preparation and multi-properties determination of radium-containing rocklike material

Science.gov (United States)

Hong, Changshou; Li, Xiangyang; Zhao, Guoyan; Jiang, Fuliang; Li, Ming; Zhang, Shuai; Wang, Hong; Liu, Kaixuan

2018-02-01

The radium-containing rocklike material were fabricated using distilled water, ordinary Portland cement and additives mixed aggregates and admixtures according to certain proportion. The physico-mechanical properties as well as radioactive properties of the prepared rocklike material were measured. Moreover, the properties of typical granite sample were also investigated. It is found on one hand, similarities exist in physical and mechanical properties between the rocklike material and the granite sample, this confirms the validity of the proposed method; on the other hand, the rocklike material generally performs more remarkable radioactive properties compared with the granite sample, while radon diffusive properties in both materials are essentially matching. This study will provide a novel way to prepare reliable radium-containing samples for radon study of underground uranium mine.

Discrete Mathematics and the Secondary Mathematics Curriculum.

Science.gov (United States)

Dossey, John

Discrete mathematics, the mathematics of decision making for finite settings, is a topic of great interest in mathematics education at all levels. Attention is being focused on resolving the diversity of opinion concerning the exact nature of the subject, what content the curriculum should contain, who should study that material, and how that…

Studies on preparation and adaptive thermal control performance of novel PTC (positive temperature coefficient) materials with controllable Curie temperatures

International Nuclear Information System (INIS)

Cheng, Wen-long; Yuan, Shuai; Song, Jia-liang

2014-01-01

PTC (positive temperature coefficient) material is a kind of thermo-sensitive material. In this study, a series of novel PTC materials adapted to thermal control of electron devices are prepared. By adding different low-melting-point blend matrixes into GP (graphite powder)/LDPE (low density polyethylene) composite, the Curie temperatures are adjusted to 9 °C, 25 °C, 34 °C and 41 °C, and the resistance–temperature coefficients are enhanced to 1.57/°C–2.15/°C. These PTC materials remain solid in the temperature region of PTC effect, which makes it possible to be used as heating element to achieve adaptive temperature control. In addition, the adaptive thermal control performances of this kind of materials are investigated both experimentally and theoretically. The result shows that the adaptive effect becomes more significant while the resistance–temperature coefficient increases. A critical heating power defined as the initial heating power which makes the equilibrium temperature reach terminal temperature is presented. The adaptive temperature control will be effective only if the initial power is below this value. The critical heating power is determined by the Curie temperature and resistance–temperature coefficient of PTC materials, and a higher Curie temperature or resistance–temperature coefficient will lead to a larger critical heating power. - Highlights: • A series of novel PTC (positive temperature coefficient) materials were prepared. • The Curie point of PTC material can be adjusted by choosing different blend matrixes. • The resistance–temperature coefficient of PTC materials is enhanced to 2.15/°C. • The material has good adaptive temperature control ability with no auxiliary method. • A mathematical model is established to analyze the performance and applicability

Inorganic-organic hybrid polymer for preparation of affiliating material using electron beam irradiation

International Nuclear Information System (INIS)

Chung, Jaeseung; Kim, Seongeun; Kim, Byounggak; Lee, Jongchan; Park, Jihyun; Lee, Byeongcheol

2011-01-01

Recently, silver nano materials have gained a lot of attentions in a variety of applications due to the unique biological, optical, and electrical properties. Especially, the antifouling property of these material is considered to be an important character for biomedical field, marine coatings industry, biosensor, and drug delivery. In this study, we design and synthesize the inorganic-organic hybrid polymer for preparation of affiliating materials. Silver nano materials having antifouling property with different shapes are prepared by control the electron beam irradiation conditions. Inorganic-organic hybrid polymer was synthesized and characterized. → Morphology and size controlled nano materials are prepared using electron beam irradiation. → Silver nano materials having various shapes can be used for antifouling material

Perceptions on the Role of a Pre-Service Primary Teacher Education Program to Prepare Beginning Teachers to Teach Mathematics in Far North Queensland

Science.gov (United States)

Chigeza, Philemon; Jackson, Cliff; Neilson, Aaron

2017-01-01

This paper employs a collaborative auto-ethnographic method to reflect on perceptions and design of a pre-service primary teacher mathematics education program in a regional university and the role of that program to prepare beginning teachers for classroom mathematics practice in Far North Queensland. A four-phase analysis that reflected on: a…

Are students who have been educated in an outcomes-based approach prepared for university mathematics?

Directory of Open Access Journals (Sweden)

Johann Engelbrecht

2009-09-01

Full Text Available Following the political changes of 1994 in South Africa, the decision was taken to replace the traditional skills-based education system at primary and secondary school level (Grades 1 - 12 with an outcomes-based education system (OBE. The OBE approach, referred to as Curriculum 2005, was introduced into schools in 1998. The implementation of the OBE system did not occur without problems, giving rise to revised initiatives and a fair amount of criticism. The 2009 intake of students at universities is the first group of students that had been subjected to the OBE approach for their entire school career. This is also the first group of students for whom some form of mathematics was compulsory up to Grade 12 level in the form of mathematics or mathematical literacy. These students were characterised by the fact that their mathematics marks for Grade 12 were exceptionally high and that many more students qualified for university entrance. This article reports on the impact of this new education system on the mathematics prepared-ness of students entering university. The study involves an empirical analysis of the students in the first-year mathematics course for engineering students at the University of Pretoria as well as an analysis of a questionnaire completed by experienced lecturers at this university. The question addressed in this article is how the 2009 intake of students cope with mathematics at university level with regard to Performance General attributes Mathematical attributes Content-related attributesResults indicate a decrease in mathematics performance of these students at university level and that the inflated matric marks result in unjustified expectations. However, it is not unusual for marks to decrease from school to university and there is still too little evidence for serious concern. The study also indicates that these students seem to be better equipped with regard to personal attributes such as self-confidence and

Opinions of Secondary School Mathematics Teachers on Mathematical Modelling

Science.gov (United States)

Tutak, Tayfun; Güder, Yunus

2013-01-01

The aim of this study is to identify the opinions of secondary school mathematics teachers about mathematical modelling. Qualitative research was used. The participants of the study were 40 secondary school teachers working in the Bingöl Province in Turkey during 2012-2013 education year. Semi-structured interview form prepared by the researcher…

Preparation and characterization of a new carbonaceous material for electrochemical systems

Directory of Open Access Journals (Sweden)

ZI JI LIN

2010-02-01

Full Text Available A new carbonaceous material was successfully prepared by the py-rolysis of scrap tire rubber at 600 °C under a nitrogen atmosphere. The physical characteristics of the prepared carbonaceous material were studied by scanning electron microscopy (SEM, X-ray powder diffraction (XRD and X-ray photoelectron spectroscopy (XPS. It was proved that the carbonaceous material had a disordered structure and spherical morphology with an average particle size about 100 nm. The prepared carbonaceous material was also used as electrodes in electrochemical systems to examine its electrochemical performances. It was demonstrated that it delivered a lithium insertion capacity of 658 mA h g-1 during the first cycle with a coulombic efficiency of 68 %. Cyclic voltammograms test results showed that a redox reaction occurred during the cycles. The chemical diffusion coefficient based on the impedance diagram was about 10-10 cm2 s-1. The pyrolytic carbonaceous material derived from scrap tire rubber is therefore considered to be a potential anode material in lithium secondary batteries or capacitors. Furthermore, it is advantageous for environmental protection.

Mathematical modeling of phase interaction taking place in materials processing

International Nuclear Information System (INIS)

Zinigrad, M.

2002-01-01

The quality of metallic products depends on their composition and structure. The composition and the structure are determined by various physico-chemical and technological factors. One of the most important and complicated problems in the modern industry is to obtain materials with required composition, structure and properties. For example, deep refining is a difficult task by itself, but the problem of obtaining the material with the required specific level of refining is much more complicated. It will take a lot of time and will require a lot of expanses to solve this problem empirically and the result will be far from the optimal solution. The most effective way to solve such problems is to carry out research in two parallel direction. Comprehensive analysis of thermodynamics, kinetics and mechanisms of the processes taking place at solid-liquid-gaseous phase interface and building of the clear well-based physico-chemical model of the above processes taking into account their interaction. Development of mathematical models of the specific technologies which would allow to optimize technological processes and to ensure obtaining of the required properties of the products by choosing the optimal composition of the raw materials. We apply the above unique methods. We developed unique methods of mathematical modeling of phase interaction at high temperatures. These methods allows us to build models taking into account: thermodynamic characteristics of the processes, influence of the initial composition and temperature on the equilibrium state of the reactions, kinetics of homogeneous and heterogeneous processes, influence of the temperature, composition, speed of the gas flows, hydrodynamic and thermal factors on the velocity of the chemical and diffusion processes. The models can be implemented in optimization of various metallurgical processes in manufacturing of steels and non-ferrous alloys as well as in materials refining, alloying with special additives

A mathematical medley fifty easy pieces on mathematics

CERN Document Server

Szpiro, George G

2010-01-01

Szpiro's book provides a delightful, well-written, eclectic selection of mathematical tidbits that makes excellent airplane reading for anyone with an interest in mathematics, regardless of their mathematical background. Excellent gift material. -Keith Devlin, Stanford University, author of The Unfinished Game and The Language of Mathematics It is great to have collected in one volume the many varied, insightful and often surprising mathematical stories that George Szpiro has written in his mathematical columns for the newspapers through the years. -Marcus du Sautoy, Oxford University, author

Molten salt processes in special materials preparation

International Nuclear Information System (INIS)

Krishnamurthy, N.; Suri, A.K.

2013-01-01

As a class, molten salts are the largest collection of non aqueous inorganic solvents. On account of their stability at high temperature and compatibility to a number of process requirements, molten salts are considered indispensable to realize many of the numerous benefits of high temperature technology. They play a crucial role and form the basis for numerous elegant processes for the preparation of metals and materials. Molten salt are considered versatile heat transfer media and have led to the evolution of many interesting reactor concepts in fission and possibly in fusion. They also have been the basis of thinking for few novel processes for power generation. While focusing principally on the actual utilization of molten salts for a variety of materials preparation efforts in BARC, this lecture also covers a few of the other areas of technological applications together with the scientific basis for considering the molten salts in such situations. (author)

Preparation and evaluation of reference materials for accountancy analysis. (2) Evaluation results

International Nuclear Information System (INIS)

Sumi, Mika; Abe, Katsuo; Kageyama, Tomio; Nakazawa, Hiroaki; Takamatsu, Mai; Kacchi, Tomokazu; Murakami, Toshiki; Ai, Hironobu

2009-01-01

Destructive analysis for accountancy at nuclear fuel facilities should attain international target values for measurement uncertainties in safeguarding nuclear materials (ITVs). Since measurement uncertainties of isotope dilution mass spectrometry depend on uncertainties of spikes (standard materials) used, utilizing highly reliable standard material is essential. The LSD spikes prepared under collaboration work with JAEA and JNFL has different Pu/U ratio and smaller nuclear material in a spike compared with the LSD spikes used a safeguard laboratories, and the value of Pu which separated and purified from MOX and used as raw material for one of the LSD spike prepared at JAEA were measured at JAEA. Uncertainties of the prepared LSD spikes and the measurement results of actual samples with these LSD spikes were evaluated based on ISO-GUM and compared with ITVs. (author)

Design and Development Computer-Based E-Learning Teaching Material for Improving Mathematical Understanding Ability and Spatial Sense of Junior High School Students

Science.gov (United States)

Nurjanah; Dahlan, J. A.; Wibisono, Y.

2017-02-01

This paper aims to make a design and development computer-based e-learning teaching material for improving mathematical understanding ability and spatial sense of junior high school students. Furthermore, the particular aims are (1) getting teaching material design, evaluation model, and intrument to measure mathematical understanding ability and spatial sense of junior high school students; (2) conducting trials computer-based e-learning teaching material model, asessment, and instrument to develop mathematical understanding ability and spatial sense of junior high school students; (3) completing teaching material models of computer-based e-learning, assessment, and develop mathematical understanding ability and spatial sense of junior high school students; (4) resulting research product is teaching materials of computer-based e-learning. Furthermore, the product is an interactive learning disc. The research method is used of this study is developmental research which is conducted by thought experiment and instruction experiment. The result showed that teaching materials could be used very well. This is based on the validation of computer-based e-learning teaching materials, which is validated by 5 multimedia experts. The judgement result of face and content validity of 5 validator shows that the same judgement result to the face and content validity of each item test of mathematical understanding ability and spatial sense. The reliability test of mathematical understanding ability and spatial sense are 0,929 and 0,939. This reliability test is very high. While the validity of both tests have a high and very high criteria.

Preparation of sewage treatment material PVFM

Directory of Open Access Journals (Sweden)

Wenling YANG

2018-04-01

Full Text Available In order to study the optimal operating condition of the sewage treatment material PVFM(polyvinyl formal, the mechanical blowing method and the chemical foaming method are adopted. Single-factor experiments and orthogonal experiments are conducted to study the factors including the amount of raw materials, reaction time and reaction temperature influencing the preparation of the material PVFM. The material is characterized by SEM. The properties of the material are explored through the contrastive experiments of sewage treatment. The results show that when PVA mass concentration is 9% (50 mL, cellulose content is 0.4 g, sulfuric acid content is 6 mL, formaldehyde content is 6 mL, SDS content is 0.4 g, carbonate calcium content is 0.8 g, reaction temperature is 30 ℃, the dripping time of sulfuric acid is 9 minutes, the dripping time of formaldehyde is 4 minutes, and the curing time is 8 hours, the material has good physical and chemical property, and the results of the contrastive experiments of sewage treatment show that PVFM has good removal effects on both COD and NH4+-N in simulated sewage. The sewage treatment material PVFM with good properties can be obtained by the mechanical blowing method and the chemical foaming method.

Career information in the mathematical sciences (CIMS). Final report, November 1, 1992--October 31, 1995

Energy Technology Data Exchange (ETDEWEB)

Sterrett, A.

1996-01-29

This report documents the preparation and distribution of materials designed to aid students is assessing their interests in and prospects for a career in the mathematical sciences. Activities included the preparation of two books, two videos, a world wide web home page, and a workshop meeting on ``Math in Careers`` held at the University of California at Berkeley in January, 1995.

Porphyrinosilica and metalloporphyrinosilica: hybrid organic-inorganic materials prepared by sol-gel processing

Directory of Open Access Journals (Sweden)

YASSUKO IAMAMOTO

2000-03-01

Full Text Available New materials porphyrinosilica and metalloporphyrinosilica template have been obtained by a sol-gel processing where functionalyzed porphyrins and metalloporphyrins "building blocks" were assembled into a three-dimensional silicate network. The optimized conditions for preparation of these materials are revised. The monomer precursors porphyrinopropylsilyl and metalloporphyrinopropylsilyl preparation reactions and subsequent one pot sol-gel processing with tetraethoxysilane are discussed. In the case of metalloporphyrins the nitrogen base coordinates to the central metal and acts as a template in the molecular imprinting technique. UV-visible absorption spectroscopy, thermogravimetric analysis, electron paramagnetic resonance, nuclear magnetic spectra, infrared spectra, luminescence spectra, surface area and electron spectroscopy imaging of the materials are used to characterize the prepared materials. The catalytic activities of these metalloporphyrinosilica- template are compared.

Porphyrinosilica and metalloporphyrinosilica: hybrid organic-inorganic materials prepared by sol-gel processing

Science.gov (United States)

Iamamoto; Sacco; Biazzotto; Ciuffi; Serra

2000-01-01

New materials porphyrinosilica and metalloporphyrinosilica template have been obtained by a sol-gel processing where functionalyzed porphyrins and metalloporphyrins "building blocks" were assembled into a three-dimensional silicate network. The optimized conditions for preparation of these materials are revised. The monomer precursors porphyrinopropylsilyl and metalloporphyrinopropylsilyl preparation reactions and subsequent one pot sol-gel processing with tetraethoxysilane are discussed. In the case of metalloporphyrins the nitrogen base coordinates to the central metal and acts as a template in the molecular imprinting technique. UV-visible absorption spectroscopy, thermogravimetric analysis, electron paramagnetic resonance, nuclear magnetic spectra, infrared spectra, luminescence spectra, surface area and electron spectroscopy imaging of the materials are used to characterize the prepared materials. The catalytic activities of these metalloporphyrinosilica-template are compared.

Preparation of thin layer materials with macroporous microstructure for SOFC applications

International Nuclear Information System (INIS)

Marrero-Lopez, D.; Ruiz-Morales, J.C.; Pena-Martinez, J.; Canales-Vazquez, J.; Nunez, P.

2008-01-01

A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range. - Graphical abstract: Thin films materials of mixed oxides with potential application in SOFC devices have been prepared with macroporous microstructure using PMMA microspheres as pore formers. Display Omitted

THE DEVELOPMENT OF ELECTRONIC TEACHING MATERIALS BY FLIPBOOK ASSISTANCE BASED PROBLEM SOLVING SKILL WITH CTL APPROACH ON LEARNING MATHEMATICS CLASS V

Directory of Open Access Journals (Sweden)

RUSNILAWATI Eva Gustiana RUSNILAWATI

2018-01-01

Full Text Available The purpose of this research is to produce Flipbook-based Electronic Teaching Materials (BAE based on problem solving skills with CTL Approach on Vocational School Class V learning valid, practical, and effective. This type of research is development research (Development Research. This research developed Flipbook-assisted Electronic Teaching Materials (BAE on the mathematics learning of Class V Primary School by using the 4-D development model developed by Thiagarajan, Semmel, and Semmel. The validation results show that the developed Teaching Materials are worthy of use with a good minimum category. The results of the experiments show that Electronic Materials developed are practical and effective. Completed learning in the classical has reached the minimum criteria of 75% that is for problem-solving test reached 86%. Based on a questionnaire of attitudes toward mathematics, 88% of students showed an increase in attitude scores on mathematics, and 85% of students showed attitudes toward mathematics with a good minimum category.

The opinions of primary school teachers’ candidates towards material preparation and usage

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Zeynep Genc

2017-04-01

Full Text Available Abstract Instruction materials help students to acquire more memorable information. Instruction materials have an important effect on providing more permanent and simple way of learning in every step of education. Instruction materials are the most frequently used by primary school teachers. Primary school teachers should support their lectures with instruction materials in order to provide permanent learning. The Teaching Technologies and Material Designing (TTMD course which is one of the compulsory courses that students must take aims to acquire students the information and skills related with the preparation and use of materials. Evaluation of TTMD course is important in terms of the effectiveness of the course which provides the opportunity of motivating the students to learn by attracting their attention, keeping their attentions alive, making abstract concepts more concrete, facilitating the acquisition of knowledge in an organized way in the process of learning and teaching. In this context, it was aimed to determine the opinions of students in the department of primary school teaching about preparation and use of materials through teaching practice which is done within TTMD course in this study. This study is a descriptive study based on qualitative data. The sample of this research included 37 students from the department of primary school teaching who took TTMD course in the second semester in 2014-2015 academic year at Ataturk Education Faculty of Near East University or students who took this course in previous academic years. The data of this research were collected with structured interview form. According to the results, it was revealed that primary school teachers’ candidates attach importance to prepare and use materials based on their answers about the use and preparation of materials in instruction. When the opinions of primary school teachers candidates about the criteria that they give value in preparing and using

Graphene Emerges as a Versatile Template for Materials Preparation.

Science.gov (United States)

Li, Zhengjie; Wu, Sida; Lv, Wei; Shao, Jiao-Jing; Kang, Feiyu; Yang, Quan-Hong

2016-05-01

Graphene and its derivatives are emerging as a class of novel but versatile templates for the controlled preparation and functionalization of materials. In this paper a conceptual review on graphene-based templates is given, highlighting their versatile roles in materials preparation. Graphene is capable of acting as a low-dimensional hard template, where its two-dimensional morphology directs the formation of novel nanostructures. Graphene oxide and other functionalized graphenes are amphiphilic and may be seen as soft templates for formatting the growth or inducing the controlled assembly of nanostructures. In addition, nanospaces in restacked graphene can be used for confining the growth of sheet-like nanostructures, and assemblies of interlinked graphenes can behave either as skeletons for the formation of composite materials or as sacrificial templates for novel materials with a controlled network structure. In summary, flexible graphene and its derivatives together with an increasing number of assembled structures show great potentials as templates for materials production. Many challenges remain, for example precise structural control of such novel templates and the removal of the non-functional remaining templates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Risks associated with nuclear material recovery and waste preparation

Energy Technology Data Exchange (ETDEWEB)

Fullwood, R R; Erdmann, R C

1983-01-01

An analysis of the risk associated with nuclear material recovery and waste preparation is presented. The steps involve: reprocessing of spent fuel to recycle fissionable material, refabrication of the recovered material for use as reactor fuel, and the transportation links connecting these plants with the power plants and waste repositories. The risks considered are radiological and non-radiological, accident and routine effects on the public and workers during plant construction, operation and decommissioning.

A mathematical model for describing the mechanical behaviour of root canal instruments.

Science.gov (United States)

Zhang, E W; Cheung, G S P; Zheng, Y F

2011-01-01

The purpose of this study was to establish a general mathematical model for describing the mechanical behaviour of root canal instruments by combining a theoretical analytical approach with a numerical finite-element method. Mathematical formulas representing the longitudinal (taper, helical angle and pitch) and cross-sectional configurations and area, the bending and torsional inertia, the curvature of the boundary point and the (geometry of) loading condition were derived. Torsional and bending stresses and the resultant deformation were expressed mathematically as a function of these geometric parameters, modulus of elasticity of the material and the applied load. As illustrations, three brands of NiTi endodontic files of different cross-sectional configurations (ProTaper, Hero 642, and Mani NRT) were analysed under pure torsion and pure bending situation by entering the model into a finite-element analysis package (ANSYS). Numerical results confirmed that mathematical models were a feasible method to analyse the mechanical properties and predict the stress and deformation for root canal instruments during root canal preparation. Mathematical and numerical model can be a suitable way to examine mechanical behaviours as a criterion of the instrument design and to predict the stress and strain experienced by the endodontic instruments during root canal preparation. © 2010 International Endodontic Journal.

Development of syntax of intuition-based learning model in solving mathematics problems

Science.gov (United States)

Yeni Heryaningsih, Nok; Khusna, Hikmatul

2018-01-01

The aim of the research was to produce syntax of Intuition Based Learning (IBL) model in solving mathematics problem for improving mathematics students’ achievement that valid, practical and effective. The subject of the research were 2 classes in grade XI students of SMAN 2 Sragen, Central Java. The type of the research was a Research and Development (R&D). Development process adopted Plomp and Borg & Gall development model, they were preliminary investigation step, design step, realization step, evaluation and revision step. Development steps were as follow: (1) Collected the information and studied of theories in Preliminary Investigation step, studied about intuition, learning model development, students condition, and topic analysis, (2) Designed syntax that could bring up intuition in solving mathematics problem and then designed research instruments. They were several phases that could bring up intuition, Preparation phase, Incubation phase, Illumination phase and Verification phase, (3) Realized syntax of Intuition Based Learning model that has been designed to be the first draft, (4) Did validation of the first draft to the validator, (5) Tested the syntax of Intuition Based Learning model in the classrooms to know the effectiveness of the syntax, (6) Conducted Focus Group Discussion (FGD) to evaluate the result of syntax model testing in the classrooms, and then did the revision on syntax IBL model. The results of the research were produced syntax of IBL model in solving mathematics problems that valid, practical and effective. The syntax of IBL model in the classroom were, (1) Opening with apperception, motivations and build students’ positive perceptions, (2) Teacher explains the material generally, (3) Group discussion about the material, (4) Teacher gives students mathematics problems, (5) Doing exercises individually to solve mathematics problems with steps that could bring up students’ intuition: Preparations, Incubation, Illumination, and

Preservice Secondary Teachers Perceptions of College-Level Mathematics Content Connections with the Common Core State Standards for Mathematics

Science.gov (United States)

Olson, Travis A.

2016-01-01

Preservice Secondary Mathematics Teachers (PSMTs) were surveyed to identify if they could connect early-secondary mathematics content (Grades 7-9) in the Common Core State Standards for Mathematics (CCSSM) with mathematics content studied in content courses for certification in secondary teacher preparation programs. Respondents were asked to…

Mathematics, Language, and Learning: A Longitudinal Study of Elementary Teachers and Their Mathematics Teaching Practices

OpenAIRE

Yeh, Cathery

2016-01-01

Elementary school mathematics has gained increased attention in the last few decades. A growing field of research has studied the programmatic design and development of elementary mathematics teaching in teacher education, however, few studies have examined longitudinally the mathematics teaching of novice elementary teachers. Existing longitudinal studies on elementary mathematics teaching have generally focused on the effects of teacher preparation on their beginning practices and have exam...

Preparation of oxide materials from metal alkoxides

International Nuclear Information System (INIS)

Turevskaya, E.P.; Turova, N.Ya.; Yanovskaya, M.I.

2000-01-01

The results of studies on the sol-gel technologies on the basis of alkoxides are presented. The synthesis and properties of titanates zirconates, niobates, tantalates, vanadates and solid solutions on the basis of Mo, W and Bi oxides, iron oxides and high-temperature superconductors are presented. The most important aspects, determining the choice of optimal conditions for preparation of oxides of concrete compositions with required properties are pointed out. Accomplishment of the whole chain of studies made it possible to synthesize a broad range of metal alkoxides and study their properties and also carry out large-scale studies on preparation of various oxides and materials on the basis thereof, using the source base of the sol-gel method [ru

Process for preparing coating materials

International Nuclear Information System (INIS)

Ryoke, Hideyasu; Kobayashi, Juichi; Kobayashi, Kei.

1972-01-01

A coating material curable with ionizing radiations or ultraviolet radiation can be prepared by reacting a compound (A) having one OH group and at least one α,β-ethylenic or allyl group with a polyisocyanate. (A) is a diester of a dicarboxylic acid. One of the ester groups may have a terminal α,β-ethylenic or allyl group and the other contains one OH and one α,β-ethylenic or allyl group. (A) is reacted with a polyisocyanate to yield an urethane. The latter may be diluted with a vinyl monomer. When exposed to a radiation, the coating material cures to give a film excellent in adhesion, impact strength and resistances to pollution, water and solvents. Dose of the ionizing radiation (α-, β-, γ-rays, electron beams) is 0.2-20 Mrad. In one example, 116 parts of 2-hydroxyethyl acrylate was reacted with 148 parts of phthalic anhydride and 142 parts of glycidyl methacrylate to give (A). (A) was reacted with 87 parts of tolylenediisocyanate. A metallic panel was coated with the coating material and cured with electron beams (5 Mrad). Pencil hardness was H, and gel fraction measured in acetone was above 97%. The coating was excellent in resistances to solvent and chemicals, impact strength and adhesion. (Kaichi, S.)

High school mathematics teachers' perspectives on the purposes of mathematical proof in school mathematics

Science.gov (United States)

Dickerson, David S.; Doerr, Helen M.

2014-12-01

Proof serves many purposes in mathematics. In this qualitative study of 17 high school mathematics teachers, we found that these teachers perceived that two of the most important purposes for proof in school mathematics were (a) to enhance students' mathematical understanding and (b) to develop generalized thinking skills that were transferable to other fields of endeavor. We found teachers were divided on the characteristics (or features) of proofs that would serve these purposes. Teachers with less experience tended to believe that proofs in the high school should adhere to strict standards of language and reasoning while teachers with more experience tended to believe that proofs based on concrete or visual features were well suited for high school mathematics. This study has implications for teacher preparation because it appears that there is a wide variation in how teachers think about proof. It seems likely that students would experience proof very differently merely because they were seated in different classrooms.

Preparation of the Jaws Damaged Parts from Composite Biopolymers Materials

Directory of Open Access Journals (Sweden)

Riyam A. Al-husseini

2017-10-01

Full Text Available Composite materials composing of fusing two materials or more are disaccorded in mechanical and physical characteristics, The studied the effect of changing in the reinforcement percentage by Hydroxyapatite Prepared nano world via the size of the nanoscale powder manufacturing manner chemical precipitation and microwave powders were two types their preparations have been from natural sources: the first type of eggshells and the other from the bones of fish in mechanical Properties which include the tensile strength, elastic modulus, elongation, hardness and tear for composite material consisting of Silicone rubber (SIR reinforced by (µ-n-HA, after strengthening silicone rubber Protect proportions (5,10,15,20 wt% of Article achieved results that increase the additive lead to increased hardness while tougher and modulus of elasticity decreases with added as shown in the diagrams.

Mathematical model of silicon smelting process basing on pelletized charge from technogenic raw materials

Science.gov (United States)

Nemchinova, N. V.; Tyutrin, A. A.; Salov, V. M.

2018-03-01

The silicon production process in the electric arc reduction furnaces (EAF) is studied using pelletized charge as an additive to the standard on the basis of the generated mathematical model. The results obtained due to the model will contribute to the analysis of the charge components behavior during melting with the achievement of optimum final parameters of the silicon production process. The authors proposed using technogenic waste as a raw material for the silicon production in a pelletized form using liquid glass and aluminum production dust from the electrostatic precipitators as a binder. The method of mathematical modeling with the help of the ‘Selector’ software package was used as a basis for the theoretical study. A model was simulated with the imitation of four furnace temperature zones and a crystalline silicon phase (25 °C). The main advantage of the created model is the ability to analyze the behavior of all burden materials (including pelletized charge) in the carbothermic process. The behavior analysis is based on the thermodynamic probability data of the burden materials interactions in the carbothermic process. The model accounts for 17 elements entering the furnace with raw materials, electrodes and air. The silicon melt, obtained by the modeling, contained 91.73 % wt. of the target product. The simulation results showed that in the use of the proposed combined charge, the recovery of silicon reached 69.248 %, which is in good agreement with practical data. The results of the crystalline silicon chemical composition modeling are compared with the real silicon samples of chemical analysis data, which showed the results of convergence. The efficiency of the mathematical modeling methods in the studying of the carbothermal silicon obtaining process with complex interphase transformations and the formation of numerous intermediate compounds using a pelletized charge as an additive to the traditional one is shown.

An Exploration of the Preparation and Organization of Teaching Practice Exercise to Prospective Science and Mathematics Teachers toward Improving Teaching Profession at Morogoro Teachers' College

Science.gov (United States)

Mungure, Daudi Mika

2016-01-01

This paper explored the preparation and organization of teaching practice exercise to prospective science and mathematics teachers in Tanzania teachers college specifically Morogoro Teachers' College toward improving teaching profession. Due to the challenges stated by different scholars on preparation and organization of teaching practice…

Developing Teaching Materials PISA-Based for Mathematics and Science of Junior High School

Science.gov (United States)

Somakim; Suharman, Andi; Madang, Kodri; Taufiq

2016-01-01

This research aims to develop valid and practical teaching materials for mathematics and science lesson PISA-based for junior high school students and to determine potential effects on students in scientific activity. Subjects of this study were students of Junior High School 9 Palembang (SMP Negeri 9 Palembang). The method used in this study is…

Mathematical model of the heat transfer process taking into account the consequences of nonlocality in structurally sensitive materials

Science.gov (United States)

Kuvyrkin, G. N.; Savelyeva, I. Y.; Kuvshynnikova, D. A.

2018-04-01

Creation of new materials based on nanotechnology is an important direction of modern materials science development. Materials obtained using nanotechnology can possess unique physical-mechanical and thermophysical properties, allowing their effective use in structures exposed to high-intensity thermomechanical effects. An important step in creation and use of new materials is the construction of mathematical models to describe the behavior of these materials in a wide range of changes under external effects. The model of heat conduction of structural-sensitive materials is considered with regard to the medium nonlocality effects. The relations of the mathematical model include an integral term describing the spatial nonlocality of the medium. A difference scheme, which makes it possible to obtain a numerical solution of the problem of nonstationary heat conduction with regard to the influence of the medium nonlocality on space, has been developed. The influence of the model parameters on the temperature distributions is analyzed.

Preparation and development of new Pu spike isotopic reference materials at IRMM

Energy Technology Data Exchange (ETDEWEB)

Jakopic, Rozle; Bauwens, Jeroen; Richter, Stephan; Sturm, Monika; Verbruggen, Andre; Wellum, Roger; Eykens, Roger; Kehoe, Frances; Kuehn, Heinz; Aregbe, Yetunde [Institute for Reference Materials and Measurements (IRMM) Joint Research Centre, European Commission, Geel, (Belgium)

2011-12-15

Reliable isotope measurements of nuclear material and the availability of reference materials with small uncertainties in the certified values are of great importance for safeguarding of nuclear materials. They provide the basis for a credible measurement system in the verification of states declarations of their nuclear activities. Worldwide needs for continued and improved Isotopic Reference Materials (IRM) are the main reason for developments of new nuclear reference materials at IRMM. Measurement capabilities of laboratories have evolved considerably over the years, along with progress in modern analytical techniques. Some plutonium reference materials, however, have been on the market for decades and they need to be re-certified to smaller uncertainties. Moreover, new reference materials with appropriately small uncertainties in the certified values need to be made available enabling measurement laboratories to reduce their combined measurement uncertainties. Such high quality plutonium isotopic reference materials are essential for laboratories striving to meet the International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials (ITVs). The preparation and the certification of such materials are demanding and challenging tasks that require state-of-theart measurement procedures and equipment. The Institute for Reference Materials and Measurements (IRMM) has repeatedly demonstrated its capabilities in plutonium analysis and represents one of the few institutes that supplies plutonium IRMs worldwide. An inter-calibration campaign has been set up at IRMM inter-linking selected plutonium spike IRMs. In the scope of this compatibility study, new reference materials have been prepared for Isotope Dilution Mass Spectrometry (IDMS) in nuclear fuel cycle measurements. A new series of large-sized dried (LSD) spikes, IRMM- 1027n, has been prepared and certified for plutonium and uranium amount content and isotopic composition. These mixed

Effects of an Additional Mathematics Content Course on Elementary Teachers' Mathematical Beliefs and Knowledge for Teaching

Science.gov (United States)

Smith, Marvin E.; Swars, Susan L.; Smith, Stephanie Z.; Hart, Lynn C.; Haardorfer, Regine

2012-01-01

This longitudinal study examines the effects of changes in an elementary teacher preparation program on mathematics beliefs and content knowledge for teaching of two groups of prospective teachers (N = 276): (1) those who completed a program with three mathematics content courses and two mathematics methods courses and (2) those who completed a…

The Effects of Digital Learning Material on Students' Mathematics Learning in Vocational Education

Science.gov (United States)

Zwart, Diana P.; Van Luit, Johannes E. H.; Noroozi, Omid; Goei, Sui Lin

2017-01-01

This study investigates the effects of Digital Learning Material (DLM) including instructional clips, online guidance, structuring of content, and a collaboration tool on students' mathematics learning in Dutch vocational education. A pretest-posttest design was used. Apprenticeship students were asked to complete assignments and to discuss them…

Present status and future plans of the study for preparation of Pu reference materials

International Nuclear Information System (INIS)

Sumi, Mika; Kageyama, Tomio; Suzuki, Toru

2007-01-01

All accountancy analysis at the Plutonium Fuel Development Center of JAEA is performed by isotope dilution mass spectrometry with well-characterized standard materials. Though Pu reference materials has been supplied from foreign country, importing those Pu materials is gradually becoming more difficult and may be almost impossible to import them in future. Thus, in order to establish the capability and expertise for the preparation of Pu reference materials, JAEA has started collaborative work with NBL who has high skills for preparing and supplying nuclear reference materials for long periods. One of the targets of this collaboration is preparation of standard material for IDMS (LSD spike). MOX powder which has been stored in JAEA was dissolved and Purified to obtain Pu solution. A small portion of the Purified solution was transported to NBL for analysis. LSD spike will be prepared from this Pu solution and then validation analysis and performance test including stability test will be performed with NBL and JAEA. This report presents status and future plans for the collaboration work. (author)

Developing Teaching Materials Using Comic Media to Enhance Students’ Mathematical Communication

Science.gov (United States)

Yulian, V. N.

2018-04-01

Teaching materials are a set of materials that are arranged systematically written or not, to create an environment or atmosphere that allows students to learn. The purpose of this study is to provide an overview of how the development of teaching materials using comic media that enhance mathematical communication, as well as feasible and effective teaching materials developed. Research method used in this research is Research and Development. In the sense of research contains about how to develop teaching materials through several stages such as validation by experts, as well as revisions. Sources of data used in this study were students and teachers SMK Bandung Barat. The results showed that the teaching materials developed feasible and effective use for students of class X SMK Bandung Barat. Teaching materials received a proper assessment of the experts after going through several stages of revision, in addition to the effective teaching materials used by students seen from the liveliness and the value of classical completeness that reaches more 85% of students. Based on the result of the research, it can be concluded that the developed teaching material gets the proper judgment from the expert, and effectively used in the learning by the students of X-1 Pharmacy class with the classical completeness reach 86% and the student activity is 91,4%.

Mathematics Courses for the Prospective Teacher.

Science.gov (United States)

Kistler, Barbara C.

This paper suggests that faculty at two-year institutions need to become partners with colleges of education and K-12 teachers of mathematics in preparing future mathematics teachers. The paper presents the following: a summary of recommendations on programs for prospective teachers; a summary of recommendations about mathematics courses for…

Preparation of silica-based hybrid materials by gamma irradiation

International Nuclear Information System (INIS)

Gomes, S.R.; Margaca, F.M.A.; Miranda Salvado, I.M.; Ferreira, L.M.; Falcao, A.N.

2006-01-01

Gamma-ray irradiation is well known to promote the crosslinking of polymer chains. The method is now used by the authors to prepare hybrid materials from a mixture of polymer and metallic alkoxides of silicium and zirconium that are usually obtained via the sol-gel process. Macroscopically homogeneous and transparent hybrid materials have been obtained by γ-irradiation of polydimethylsiloxane (PDMS), tetraethylorthosilicate (TEOS) and zirconium propoxide (PrZr). The influence of several parameters has been studied. The dose rate was found to have no significant impact in the prepared material. The polymer molecular weight was also observed not to play any special role. It was found that all irradiated samples consist of a polymer gel matrix. In the case where both alkoxides are present there are inorganic oxide regions linked to the PDMS network. However when one of the alkoxides is absent there is no formation of inorganic oxide regions linked to the polymer matrix, there being only a few individual derived molecules of the other alkoxide linked to the polymer

"Take Me to the Mathematical Circle!"

OpenAIRE

Veilande, Ingrida

2012-01-01

Preparing the students for various mathematical contests are the key goals of mathematical circles in Latvian schools. The reason why mathematical circles for students of primary schools are organised rather seldom is that problem sets of Olympiads are mainly created for students of 5th to 12th grades. The young participants of circles have to be introduced with the basic principles of Olimpiads mathematics too.

Development of problem-based learning material for physics mathematics and its implementation

Directory of Open Access Journals (Sweden)

Pujayanto Pujayanto

2017-02-01

Full Text Available The research aims to develop Problem Based Learning material teaching of Mathematics Physics and to know the effect on the cognitive capability of undergraduate students. The research uses development method of Borg and Gall. There are ten steps such as data collection, planning, product drafting, pretest, pretest revise 1, main test, main test revise 2, posttest, final revision, and dissemination and implementation. The data collection uses questionnaire and cognitive test which will support the qualitative data. The result shows that the criterion of developing problem-based learning teaching materials is 5 level category when 43.33% respondents rate 5 level category and the others give 4 level category. Furthermore, students which use the materials increased and the most of the students have acquired cognitive value exceeds the value of minimum completeness criteria.

DEVELOPING GUIDED DISCOVERY LEARNING MATERIALS USING MATHEMATICS MOBILE LEARNING APPLICATION AS AN ALTERNATIVE MEDIA FOR THE STUDENTS CALCULUS II

Directory of Open Access Journals (Sweden)

Sunismi .

2015-12-01

Full Text Available Abstract: The development research aims to develop guided-discovery learning materials of Calculus II by implementing Mathematics Mobile Learning (MML. The products to develop are MML media of Calculus II using guided discovery model for students and a guide book for lecturers. The study employed used 4-D development model consisting of define, design, develop, and disseminate. The draft of the learning materials was validated by experts and tried-out to a group of students. The data were analyzed qualitatively and quantitatively by using a descriptive technique and t-test. The findings of the research were appropriate to be used ad teaching media for the students. The students responded positively that the MML media of Calculus II using the guided-discovery model was interestingly structured, easily operated through handphones (all JAVA, android, and blackberry-based handphones to be used as their learning guide anytime. The result of the field testing showed that the guided-discovery learning materials of Calculus II using the Mathematics Mobile Learning (MML application was effective to adopt in learning Calculus II. Keywords: learning materials, guided-discovery, mathematics mobile learning (MML, calculus II PENGEMBANGAN BAHAN AJAR MODEL GUIDED DISCOVERY DENGAN APLIKASI MATHEMATICS MOBILE LEARNING SEBAGAI ALTERNATIF MEDIA PEMBELAJARAN MAHASISWA MATAKULIAH KALKULUS II Abstrak: Penelitian pengembangan ini bertujuan untuk mengembangkan bahan ajar matakuliah Kalkulus II model guided discovery dengan aplikasi Mathematics Mobile Learning (MML. Produk yang dikembangkan berupa media MML Kalkulus II dengan model guided discovery untuk mahasiswa dan buku panduan dosen. Model pengembangan menggunakan 4-D yang meliputi tahap define, design, develop, dan dissemination. Draf bahan ajar divalidasi oleh pakar dan diujicobakan kepada sejumlah mahasiswa. Data dianalisis secara kualitatif dan kuantitatif dengan teknik deskriptif dan uji t. Temuan penelitian

[Biomimetic nanohydroxyapatite/gelatin composite material preparation and in vitro study].

Science.gov (United States)

Li, Siriguleng; Hu, Xiaowen

2014-09-01

To prepare nHA/gelatin porous scaffold and to evaluate its physical and chemical properties and biocompatibility. We used nano-powders of HA and gelatin to prepare 3D porous composite scaffold by freeze-drying technique, and used scanning electron microscope, fourier transform infrared spectroscopy and universal testing machine to characterize the composite material. Osteoblasts were primarily cultured, and the third-passage osteoblasts were co-cultured with the composite material. The cell adhesion and morphology were examined under scanning electron microscope. The cell viability analysis was performed by MTT assay, and the alkaline phosphatase activity was measured with alkaline phosphatase kit. Scanning electron microscope showed that the scaffold possessed a 3-dimensional interconnected homogenous porous structure with pore sizes ranging from 150 to 400 μm. Fourier transform infrared spectroscopy showed that the composite material had a strong chemical bond between the inorganic phase and organic phase. The scaffold presented the compressive strength of (3.28 ± 0.51) MPa and porosities of (80.6 ± 4.1)%. Composite materials showed features of had good biocompatibility. Mouse osteoblasts were well adhered and spread on the materials. The grade of the cell toxicity ranged from I to II. On the 5th and 7th day the proliferative rate of osteoblasts on scaffolds in the composite materials was significantly higher than that in the control group. The activity of alkaline phosphatase was obviously higher than that in the control group on Day 1 and 3. Nano-hydroxyapatite and gelatin in certain proportions and under certain conditions can be prepared into a composite biomimetic porous scaffolds with high porosity and three-dimensional structure using freeze-drying method. The scaffold shows good biocompatibility with mouse osteoblasts and may be a novel scaffolds for bone tissue engineering.

Mathematical Investigations for Supporting Pre-Service Primary Teachers Repeating a Mathematics Education Course

Science.gov (United States)

Bailey, Judy

2014-01-01

Preparing to become an effective primary school mathematics teacher is a challenging and complex task; and is influenced by one's past experiences, personal knowledge of, and beliefs and attitudes towards mathematics. This paper examines the experiences of a small group of pre-service teachers who did not pass their first year mathematics…

Preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage

International Nuclear Information System (INIS)

Konuklu, Yeliz; Ersoy, Orkun

2016-01-01

Highlights: • Sepiolite-based phase change material nanocomposites were prepared. • An easy direct impregnation process was used. • This paper is one of the first study about sepiolite-based phase change material nanocomposites. • Influence of PCM type on thermal properties of nanocomposites was reported. - Abstract: This paper is one of the first study about the preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage applications. Sepiolite is an important natural fibrous raw material. Nanoscale fibrous tubular structure of sepiolite becomes important in nanocomposite preparation. In this study, sepiolite/paraffin and sepiolite/decanoic acid nanocomposites were manufactured by the direct impregnation method. By the preparation of nanocomposites, PCM move in tubular channels of sepiolite, phase changing occurs in these tubes and surface area increases like as in microencapsulation. The structure and properties of nanocomposites PCMs (CPCM) have been characterized via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The SEM results prove the successful preparation of phase change material/sepiolite nanocomposites and point out that the fibers of sepiolite is modified with phase change materials in the nanocomposite. The phase change enthalpies of melting and freezing were about 62.08 J/g and −62.05 J/g for sepiolite/paraffin nanocomposites and 35.69 J/g and −34.55 J/g for sepiolite/decanoic acid nanocomposites, respectively. The results show that PCM/sepiolite nanocomposites were prepared successfully and their properties are very suitable for thermal energy storage applications.

Introducing philosophy of mathematics

CERN Document Server

Friend, Michele

2014-01-01

What is mathematics about? Does the subject-matter of mathematics exist independently of the mind or are they mental constructions? How do we know mathematics? Is mathematical knowledge logical knowledge? And how is mathematics applied to the material world? In this introduction to the philosophy of mathematics, Michele Friend examines these and other ontological and epistemological problems raised by the content and practice of mathematics. Aimed at a readership with limited proficiency in mathematics but with some experience of formal logic it seeks to strike a balance between conceptual acc

The analysis of mathematics teachers' learning on algebra function limit material based on teaching experience difference

Science.gov (United States)

Ma'rufi, Budayasa, I. Ketut; Juniati, Dwi

2017-08-01

The aim of this study was to describe the analysis of mathematics teachers' learning on algebra function limit material based on teaching experience difference. The purpose of this study is to describe the analysis of mathematics teacher's learning on limit algebraic functions in terms of the differences of teaching experience. Learning analysis focused on Pedagogical Content Knowledge (PCK) of teachers in mathematics on limit algebraic functions related to the knowledge of pedagogy. PCK of teachers on limit algebraic function is a type of specialized knowledge for teachers on how to teach limit algebraic function that can be understood by students. Subjects are two high school mathematics teacher who has difference of teaching experience they are one Novice Teacher (NP) and one Experienced Teacher (ET). Data are collected through observation of learning in the class, videos of learning, and then analyzed using qualitative analysis. Teacher's knowledge of Pedagogic defined as a knowledge and understanding of teacher about planning and organizing of learning, and application of learning strategy. The research results showed that the Knowledge of Pedagogy on subject NT in mathematics learning on the material of limit function algebra showed that the subject NT tended to describe procedurally, without explaining the reasons why such steps were used, asking questions which tended to be monotonous not be guiding and digging deeper, and less varied in the use of learning strategies while subject ET gave limited guidance and opportunities to the students to find their own answers, exploit the potential of students to answer questions, provide an opportunity for students to interact and work in groups, and subject ET tended to combine conceptual and procedural explanation.

Mathematical knowledge for teaching: Making the tacit more explicit in mathematics teacher education

Science.gov (United States)

Abdullah, Mohd Faizal Nizam Lee; Vimalanandan, Lena

2017-05-01

Teaching practice during school based experiences, afford an opportunity for pre service teachers to put into practice their knowledge for teaching mathematics. Like all knowledge, Mathematical Knowledge for Teaching (MKT) is held in both tacit and explicit form, making it especially difficult to study and map during instruction. This study investigates the tacit and explicit nature of MKT held by pre service teachers in a Malaysian Teacher Education Program and how it impacts the Mathematical Quality of their instruction (MQI). This study of three mathematics pre-service teachers (PSTs), utilised videos of mathematics lessons, reflective debriefs and interviews. The findings suggest that factors such as reflecting, peer-sharing, conferencing with mentors and observing support in making tacit knowledge more explicit during planning and instruction. Implications for preparation of mathematics teachers capable of high Mathematical Quality of Instruction are also discussed.

Preparation, characterization and optical properties of Lanthanum-(nanometer MCM-41) composite materials

International Nuclear Information System (INIS)

Zhai, Q. Z.; Wang, P.

2008-01-01

Nanometer MCM-41 molecular sieve was prepared under a base condition by using cetyltrimethylammonium bromide as template and tetraethyl orthosilicate as silica source by means of hydrothermal method. Lanthanum(III) was incorporated into the nanometer MCM-41 by a liquid phase grafting method. The prepared nano composite materials were characterized by means of powder X-ray diffraction, spectrophotometric analysis, Fourier transform infrared spectroscopy, low temperature nitrogen adsorption-desorption technique, solid diffuse reflectance absorption spectra and luminescence. The powder X-ray diffraction studies show that the nanometer MCM-41 molecular sieve is successfully prepared. The highly ordered meso porous two-dimensional hexagonal channel structure and framework of the support MCM-41 is retained intact in the prepared composite material La-(nanometer MCM-41). The spectrophotometric analysis indicates that lanthanum exists in the prepared nano composite materials. The Fourier transform infrared spectra indicate that the framework of the MCM-41 molecular sieve still remains in the prepared nano composite materials and some framework vibration peaks show blue shifts relative to those of the MCM-41 molecular sieve. The low temperature nitrogen adsorption-desorption indicates that the guest locales in the channel of the molecular sieve. Compared with bulk lanthanum oxide, the guest in the channel of the molecular sieve has smaller particle size and shows a significant blue shift of optical absorption band in solid diffuse reflectance absorption spectra. The observed blue shift in the solid state diffuse reflectance absorption spectra of the lanthanum-(nanometer MCM-41) sample show the obvious stereoscopic confinement effect of the channel of the host on the guest, which further indicates the successful encapsulation of the guest in the host. The La-(nanometer MCM-41) sample shows luminescence

Design, preparation, and application of ordered porous polymer materials

International Nuclear Information System (INIS)

Liu, Qingquan; Tang, Zhe; Ou, Baoli; Liu, Lihua; Zhou, Zhihua; Shen, Shaohua; Duan, Yinxiang

2014-01-01

Ordered porous polymer (OPP) materials have extensively application prospects in the field of separation and purification, biomembrane, solid supports for sensors catalysts, scaffolds for tissue engineering, photonic band gap materials owing to ordered pore arrays, uniform and tunable pore size, high specific surface area, great adsorption capacity, and light weight. The present paper reviewed the preparation techniques of OPP materials like breath figures, hard template, and soft template. Finally, the applications of OPP materials in the field of separation, sensors, and biomedicine are introduced, respectively. - Highlights: • Breath figures involve polymer casting under moist ambience. • Hard template employs monodisperse colloidal spheres as a template. • Soft template utilizes the etched block in copolymers as template

Mathematical Modeling and Simulations of Phase Change Materials in Basic Orthogonal Coordinate Systems

Energy Technology Data Exchange (ETDEWEB)

Rousse, Daniel; Dutil, Yvan; Ben Salah, Nizar; Lassue, Stephane

2010-09-15

Energy storage components improve the energy efficiency of systems by reducing the mismatch between supply and demand. Phase change materials are attractive since they provide a high energy storage density at constant temperatures. Nevertheless, the incorporation of such materials in a particular application often calls for numerical analyses due to the non-linear nature of the problem. The review of the mathematical models will include selected results to enable one to start his/her research with an exhaustive overview of the subject. This overview also stresses the need to match experimental investigations with recent numerical analyses.

The preparation of four biological reference materials for QUASIMEME

NARCIS (Netherlands)

Leeuwen, van S.P.J.; Pieters, H.; Boer, de J.

2004-01-01

Four biological materials have been prepared for use in QUASIMEME interlaboratory studies including a shrimp sample for metal analysis (QM01-1) and two mussel (QO01-3 and QO02-2) and one mackerel sample (QO02-1) for organic contaminant analysis.

Flipping Preservice Elementary Teachers' Mathematics Anxieties

Science.gov (United States)

Dove, Anthony; Dove, Emily

2017-01-01

In preparing future elementary educators in mathematics, helping them overcome their anxieties of mathematics and teaching mathematics is paramount. This study examined how different instructional practices (in-class lecture, flipped learning with teacher-created videos, flipped classroom with Khan Academy videos) compared in improving students'…

Preparation and characterization of hybrid materials based on polypyrrole and silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Nguyen Duc Nghia; Ngo Trinh Tung [Institute of Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam)], E-mail: ducnghia264@fpt.vn

2009-09-01

Hybrid material is one of the most promising materials classed in the 21st century because of its unique properties and its advanced applications. In this work, hybrid materials based on polypyrrole (Ppy) and silver nanoparicles were prepared and characterized. The preparation of the hybrid material was performed by the chemical polymerization method. The structure, electrical and thermal properties of Ppy/Ag hybrid materials were characterized by XRD, SEM, and TGA and the conventional four probe method. The results showed that the Ag particles of 4-8 nm were agglomerated during the in-situ polymerization of PPy and formed some clusters with the diameter of 25 -150 nm. By the addition of Ag particles, the electrical conductivity of Ppy increased with increasing Ag concentration. The thermal stability of Ppy was significantly improved by modification with Ag particles.

Preparation and characterization of hybrid materials based on polypyrrole and silver nanoparticles

International Nuclear Information System (INIS)

Nguyen Duc Nghia; Ngo Trinh Tung

2009-01-01

Hybrid material is one of the most promising materials classed in the 21st century because of its unique properties and its advanced applications. In this work, hybrid materials based on polypyrrole (Ppy) and silver nanoparicles were prepared and characterized. The preparation of the hybrid material was performed by the chemical polymerization method. The structure, electrical and thermal properties of Ppy/Ag hybrid materials were characterized by XRD, SEM, and TGA and the conventional four probe method. The results showed that the Ag particles of 4-8 nm were agglomerated during the in-situ polymerization of PPy and formed some clusters with the diameter of 25 -150 nm. By the addition of Ag particles, the electrical conductivity of Ppy increased with increasing Ag concentration. The thermal stability of Ppy was significantly improved by modification with Ag particles.

Green's function and boundary elements of multifield materials

CERN Document Server

Qin, Qing-Hua

2007-01-01

Green's Function and Boundary Elements of Multifield Materials contains a comprehensive treatment of multifield materials under coupled thermal, magnetic, electric, and mechanical loads. Its easy-to-understand text clarifies some of the most advanced techniques for deriving Green's function and the related boundary element formulation of magnetoelectroelastic materials: Radon transform, potential function approach, Fourier transform. Our hope in preparing this book is to attract interested readers and researchers to a new field that continues to provide fascinating and technologically important challenges. You will benefit from the authors' thorough coverage of general principles for each topic, followed by detailed mathematical derivation and worked examples as well as tables and figures where appropriate. In-depth explanations of the concept of Green's function Coupled thermo-magneto-electro-elastic analysis Detailed mathematical derivation for Green's functions.

Engineering Undergraduates' Views of A-Level Mathematics and Further Mathematics as Preparation for Their Degree

Science.gov (United States)

Darlington, Ellie; Bowyer, Jessica

2017-01-01

An ongoing reform programme of the post-16 Advanced "A"-level qualifications in England and Wales means that pre-university mathematics content and assessment will change from 2017. Undergraduate engineering is a subject that relies heavily on mathematics, and applicants to engineering degree programmes in the UK are required to have…

Development Mathematic Assessment to Increase Mathematical Prerequisite Ability on The Student with Learning Disabilities in Inclusive Elementary School

Science.gov (United States)

Robiansyah, S. T. U.; Nanang, F.; Hidayat

2018-01-01

The purpose of this study was to introduce about mathematic assessment is a process of obtaining data or information about the mastery of a student's mathematical skills as an ingredient in preparing a learning program. With this mathematics assessment can be known obstacles, difficulties and needs of students especially in the field of mathematic, so that the learning program will be in accordance with the potential students because it is tailored to what is required of students. This research study was conducted at elementary school of inclusive precisely at SDN Sukagalih I Bandung City based learning in setting of inclusive education. This research study is motivated by the existence of a first-grade student who has disabilities learning in mathematics, the ability of the mathematical prerequisite mastery of the classification of objects by color. The results of the research can provide a profile picture of student data information, the data obtained from the results of the development of systematic and formal mathematical assessment. After doing the development of mathematics assessment then the teacher gets important related information: 1. process the analysis of students’ learning needs, especially in the field of mathematics, 2. preparing the learning program planning according to student learning needs, 3. Designing procedural of method remedial program.

Gender and participation in mathematics and further mathematics A-levels: a literature review for the Further Mathematics Support Programme

OpenAIRE

Smith, Cathy

2014-01-01

In preparing this report I have considered evidence from over 60 documents that relate to raising girls’ participation in mathematics. These include published research papers and reports compiled by expert bodies that present an evidence base. Although research specifically addressing Further Mathematics A-level is rare, the last ten years have seen considerable efforts to synthesise and update knowledge from different research perspectives about the relationship between gender...

Preparation and characterization of novel anion phase change heat storage materials.

Science.gov (United States)

Hong, Wei; Lil, Qingshan; Sun, Jing; Di, Youbo; Zhao, Zhou; Yu, Wei'an; Qu, Yuan; Jiao, TiFeng; Wang, Guowei; Xing, Guangzhong

2013-10-01

In this paper, polyurethane phase change material was successfully prepared with TDI with BDO for hard segments and PEG for soft segments. Moreover, based on this the solid-solid phase change material, A-PCM1030 which can release anions was prepared with the successful addition of anion additives A1030 for the first time. Then the test of the above material was conducted utilizing FT-IR, DSC, TEM, WAXD and Air Ion Detector. The Results indicated that the polyurethane phase change material possesses excellent thermal stability since there was no appearance of liquid leakage and phase separation after 50 times warming-cooling thermal cycles. It also presented reversibility on absorbing and releasing heat. In addition, adding a little A1030 can increase the thermal stability and reduce phase transition temperatures, as well as reduce the undercooling of the polyurethane phase change material. In addition, the anion test results suggested that the supreme amount of anion released by A-PCM1030 could reach 2510 anions/cm3 under dynamic conditions, which is beneficial for human health.

Preparation and characterization of the fish reference material; Preparacao e caracterizacao de um material de referencia de peixe

Energy Technology Data Exchange (ETDEWEB)

Ulrich, Joao Cristiano

2011-07-01

The certified reference materials (CRMs) play an important role in obtaining measurement results traceable to the International System of Units, through an unbroken chain of comparisons. Thus, the demand for new certified reference materials (CRMs) increases every day in all areas of knowledge. The availability of reference materials, mainly in Brazil is still incipient, given that the demand far exceeds the available variety of these materials. The amount of certified reference materials available in the country is insufficient to meet the need of the scientific community and demands for development of new methodologies. Among the many areas in need of reference materials, we highlight the importance for the food trade balance for these products within the country. The certification of food products, intended both for export and for domestic consumption, requires analysis methods that provide precise and accurate results to ensure product quality. This paper describes the preparation and certification of a reference material in the fish matrix in mercury and methylmercury. The study brings together since the stage of material selection, preparation, development of homogeneity and stability studies and characterization. The certification was performed by means of measurements using two analytical techniques, flow injection analysis - cold vapor atomic absorption spectrometry (FIA-CV-AAS) and isotope dilution applied to mass spectrometry (IDMS), which is a primary method. In this work the standards of the ISO 30 (ABNT 30-34) and ISO Guide 35 was used as the basis for the preparation and characterization of the material. For the calculation of uncertainties was used the GUM and Eurachem guide. As a result, was produced and certified a lot of material in relation to the concentration of mercury (Hg = 0.271 {+-} 0.057 mg g{sup -1}) and methylmercury (MeHg = 0.245 {+-} 0.038 mg g{sup -1}), and informational values of lead and arsenic. (author)

Mathematics Teacher Education: A Model from Crimea.

Science.gov (United States)

Ferrucci, Beverly J.; Evans, Richard C.

1993-01-01

Reports on the mathematics teacher preparation program at Simferopol State University, the largest institution of higher education in the Crimea. The article notes the value of investigating what other countries consider essential in mathematics teacher education to improve the mathematical competence of students in the United States. (SM)

Preparation for microgravity - The role of the Microgravity Material Science Laboratory

Science.gov (United States)

Johnston, J. Christopher; Rosenthal, Bruce N.; Meyer, Maryjo B.; Glasgow, Thomas K.

1988-01-01

Experiments at the NASA Lewis Research Center's Microgravity Material Science Laboratory using physical and mathematical models to delineate the effects of gravity on processes of scientific and commercial interest are discussed. Where possible, transparent model systems are used to visually track convection, settling, crystal growth, phase separation, agglomeration, vapor transport, diffusive flow, and polymer reactions. Materials studied include metals, alloys, salts, glasses, ceramics, and polymers. Specific technologies discussed include the General Purpose furnace used in the study of metals and crystal growth, the isothermal dendrite growth apparatus, the electromagnetic levitator/instrumented drop tube, the high temperature directional solidification furnace, the ceramics and polymer laboratories and the center's computing facilities.

Preparing Experienced Elementary Teachers as Mathematics Specialists

Science.gov (United States)

Nickerson, Susan D.

2010-01-01

High quality teaching is critical to student learning, yet takes considerable time to develop in particular content areas. Students in high-poverty, urban settings are less likely to encounter experienced and trained teachers. Administrators from a large school district and university mathematics education faculty partnered and attempted to…

Preparation and analysis of a marble reference material

International Nuclear Information System (INIS)

Carmo Freitas, M.; Moens, L.; Seabra e Barros, J.

1988-01-01

A 7 kg stone of a Carrara marble was reduced to grains smaller than 100 μm, mixed and homogenized in order to prepare a marble reference material. The homogeneity was tested for 16 elements by instrumental neutron activation analysis (INAA). Through a one-way analysis of variance based on several analyses of each of 15 bottles and within the same bottle, it was concluded that the inter-bottle heterogeneity is not greater than the intra-bottle heterogeneity. Results on the concentration of major and trace elements in the marble reference material, obtained by different laboratories and different techniques, are given. The limestone certified reference material KALKSTEIN KH was used to evaluate measurement accuracy, to intercalibrate laboratories, and to provide compatibility of measurement data. (author) 10 refs.; 12 tabs

Radiation sterilization of some cosmetic raw materials and preparations

International Nuclear Information System (INIS)

Achmatowicz-Szmajke, T.; Bryl-Sandelewska, T.; Galazka, M.

1979-01-01

The problem of microbiological purity of cosmetic preparations is discussed. Some results obtained on the influence of ionizing radiation on organoleptic and physicochemical properties of some cosmetic raw materials and final products are reported. The samples of raw materials and the final products were irradiated with a 10 MeV electron beam from an LAE 13/9 linear accelerator located in INR. The doses delivered to the materials were 0.5 - 2.3 Mrad (5-23 kGy). Immediately after irradiation, organoleptic estimations were made and over the next few days physicochemical investigations were performed. Non-irradiated samples were investigated together with irradiated ones. (T.I.)

Preparation of Reduced Graphene Oxides as Electrode Materials for Supercapacitors

KAUST Repository

Bai, Yaocai

2012-01-01

Reduced graphene oxide as outstanding candidate electrode material for supercapacitor has been investigated. This thesis includes two topics. One is that three kinds of reduced graphene oxides were prepared by hydrothermal reduction under different

Preparation and Properties of Moisture-absorbing Film Impregnated with Polyacrylic Acid Partial Sodium Salt Material

International Nuclear Information System (INIS)

Lee, Youn Suk; Park, Insik; Choi, Hong Yeol

2014-01-01

Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at 25 .deg. C. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability

Preparation and Properties of Moisture-absorbing Film Impregnated with Polyacrylic Acid Partial Sodium Salt Material

Energy Technology Data Exchange (ETDEWEB)

Lee, Youn Suk; Park, Insik [Yonsei University, Wonju (Korea, Republic of); Choi, Hong Yeol [CJ Cheiljedang, Seoul (Korea, Republic of)

2014-08-15

Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at 25 .deg. C. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability.

An analysis of teacher’s preparation in implementing 2013 revision edition curriculum on mathematics specialization learning

Science.gov (United States)

Susilo, T.; Suryawan, A.

2018-05-01

This study aimed to determine the pedagogical competence of teachers, the readiness of planning and implementation of learning related to the implementation 2013 revised edition curriculum on mathematics specialization learning for senior high schools Wonogiri. Informants in this study there are 6 high school mathematics teachers X and XI class who teach in the school district Wonogiri. Data were collected using questionnaire method, interview, observation and documentation. Qualitative data analysis is done interactively through 4 paths: data collection, data reduction, data display, drawing conclusion. The results showed that high school mathematics teacher class X and XI in school district of Wonogiri City. The results show that most high school mathematics teachers in grade X and XI are ready to implement the 2013 revised edition curriculum and a few have not been able to implement due to internal or external factors. High school math teachers at Wonogiri district who are ready to face the 2013 revised edition curriculum have applied 10 teacher pedagogic competency indicators according to Regulation of the national education ministry Number 16 Year 2007 in learning. The readiness and implementation of mathematics learning is in line with the demands of the 2013 revised edition curriculum. Based on the teachers who are not ready, data on issues that arise in the implementation of the 2013 revised edition curriculum. Especially the problems in learning, namely mismatch of Core Competence (KI) and Basic Competence (KD) in teacher manual, material disregard in student handbook and lack of examples of problems that exist in teacher manual.

Radiation processing technology for preparation of fine shaped biomedical materials

Energy Technology Data Exchange (ETDEWEB)

Kumakura, M.; Yoshida, M.; Asano, M. (Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment); Yamanaka, H. (Gunma Univ., Maebashi (Japan). School of Medicine)

1992-06-01

Radiation processing technology for the preparation of fine shaped biomedical materials was studied from the aspect of a development of the technology and its application. Electron beam irradiation technology was applied to the preparation of fine shaped biomedical materials such as thin polymer films in diagnosis, in which enzyme and antibody were used as a bioactive substance. Electron beam cast-polymerization and electron beam repeat surface-polymerization, that are surface irradiation techniques of homogeneous hydrophilic monomer solution containing enzymes made it possible to form the immobilized antibody films. In this technique, the films with various thicknesses (50-500 [mu]m) were obtained by regulating the electron beam energy. The thin polymer films immobilizing anti-[alpha]-fetoprotein were evaluated from the aspect of immunoagents for diagnosis of liver cancer. (Author).

Mathematical physics applied mathematics for scientists and engineers

CERN Document Server

Kusse, Bruce R

2006-01-01

What sets this volume apart from other mathematics texts is its emphasis on mathematical tools commonly used by scientists and engineers to solve real-world problems. Using a unique approach, it covers intermediate and advanced material in a manner appropriate for undergraduate students. Based on author Bruce Kusse's course at the Department of Applied and Engineering Physics at Cornell University, Mathematical Physics begins with essentials such as vector and tensor algebra, curvilinear coordinate systems, complex variables, Fourier series, Fourier and Laplace transforms, differential and integral equations, and solutions to Laplace's equations

Preparation, Endorsement, and Employment of Mathematics Specialists

Science.gov (United States)

Cicmanec, Karen B. Mauck

2008-01-01

For over 30 years, educators have recommended that mathematics specialists be placed in schools to provide teachers with the resources they need to assist their students. To assess whether these recommendations have been realized, a survey was used to gather data from large school districts, the 50 states, and District of Columbia. The outcome of…

Materials to prepare hospice families for dying in the home.

Science.gov (United States)

Kehl, Karen A; Kirchhoff, Karin T; Finster, Mark P; Cleary, James F

2008-09-01

Many changes occur in the final hours of life. Family members of those dying at home need to be prepared for these changes, both to understand what is happening and to provide care. The objectives of this study were to describe (1) the written materials used by hospices to prepare families for dying in the home setting and (2) the content of such materials. Questionnaires were sent to 400 randomly selected hospices, of which 170 responded (45.3%) sending their written materials. The most frequently used publications were Gone from My Sight (n = 118 or 69.4%), Final Gifts (n = 44 or 25.9%) and Caregiving (n = 14 or 8.2%). Half (56.5%) of the hospices used other publications and a majority (n = 87 or 51.2%) used multiple publications. Materials were given to the families by nurses (78.2%) or social workers (67.6%). More than 90% of the hospices had materials that addressed the following signs of impending death: decreased fluid intake, decreased food intake, breathing pattern changes, cold extremities, mottling, increased sleeping, changes at the moment of death, audible secretions, urinary output changes, disorientation, incontinence, overall decline and restlessness. Seven signs were addressed less than 30% of the time; pain (28.2%), dyspnea (19.4%), bed-bound state (18.2%), skin changes (18.2%), vital sign changes (17.1%), surge of energy (11.8%) and mandibular breathing (5.9%). Hospice staff should know the content of the materials offered by their agency so they can verbally address the gaps between the written materials and family needs.

Preparation of resveratrol-loaded nanoporous silica materials with different structures

International Nuclear Information System (INIS)

Popova, Margarita; Szegedi, Agnes; Mavrodinova, Vesselina; Novak Tušar, Natasa; Mihály, Judith; Klébert, Szilvia; Benbassat, Niko; Yoncheva, Krassimira

2014-01-01

Solid, nanoporous silica-based spherical mesoporous MCM-41 and KIL-2 with interparticle mesoporosity as well as nanosized zeolite BEA materials differing in morphology and pore size distribution, were used as carriers for the preparation of resveratrol-loaded delivery systems. Two preparation methods have been applied: (i) loading by mixing of resveratrol and mesoporous carrier in solid state and (ii) deposition in ethanol solution. The parent and the resveratrol loaded carriers were characterized by XRD, TEM, N2 physisorption, thermal analysis, and FT-IR spectroscopy. The influence of the support structure on the adsorption capacity and the release kinetics of this poorly soluble compound were investigated. Our results indicated that the chosen nanoporous silica supports are suitable for stabilization of trans-resveratrol and reveal controlled release and ability to protect the supported compound against degradation regardless of loading method. The solid-state dry mixing appears very effective for preparation of drug formulations composed of poorly soluble compound. - Graphical abstract: trans-Resveratrol was stabilized in the pores of BEA zeolite, MCM-41and KIL2 mesoporous silicas. - Highlights: • BEA, KIL-2 and MCM-41 materials were used as carriers for resveratrol loading. • Resveratrol encapsulation in ethanol solution and solid state procedure were applied. • The solid-state preparation appears very effective for stabilization of trans-resveratrol

Preparation of resveratrol-loaded nanoporous silica materials with different structures

Energy Technology Data Exchange (ETDEWEB)

Popova, Margarita, E-mail: mpopova@orgchem.bas.bg [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Szegedi, Agnes [Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences, 1117 Budapest, Magyar tudósok körútja 2. (Hungary); Mavrodinova, Vesselina [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Novak Tušar, Natasa [National Institute of Chemistry, Ljubljana (Slovenia); Mihály, Judith; Klébert, Szilvia [Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences, 1117 Budapest, Magyar tudósok körútja 2. (Hungary); Benbassat, Niko; Yoncheva, Krassimira [Faculty of Pharmacy, 2 Dunav Str., 1000 Sofia (Bulgaria)

2014-11-15

Solid, nanoporous silica-based spherical mesoporous MCM-41 and KIL-2 with interparticle mesoporosity as well as nanosized zeolite BEA materials differing in morphology and pore size distribution, were used as carriers for the preparation of resveratrol-loaded delivery systems. Two preparation methods have been applied: (i) loading by mixing of resveratrol and mesoporous carrier in solid state and (ii) deposition in ethanol solution. The parent and the resveratrol loaded carriers were characterized by XRD, TEM, N2 physisorption, thermal analysis, and FT-IR spectroscopy. The influence of the support structure on the adsorption capacity and the release kinetics of this poorly soluble compound were investigated. Our results indicated that the chosen nanoporous silica supports are suitable for stabilization of trans-resveratrol and reveal controlled release and ability to protect the supported compound against degradation regardless of loading method. The solid-state dry mixing appears very effective for preparation of drug formulations composed of poorly soluble compound. - Graphical abstract: trans-Resveratrol was stabilized in the pores of BEA zeolite, MCM-41and KIL2 mesoporous silicas. - Highlights: • BEA, KIL-2 and MCM-41 materials were used as carriers for resveratrol loading. • Resveratrol encapsulation in ethanol solution and solid state procedure were applied. • The solid-state preparation appears very effective for stabilization of trans-resveratrol.

Preparation and characterization of hybrid materials from natural chrysotile

International Nuclear Information System (INIS)

Giraldelli, M.G.; Silva, M.L.C.P.

2010-01-01

Special attention has been given to the development of new materials from natural chrysotile. This fiber has about 40% silicon oxide in its structure with an outer layer of brucite (MgOH 2 ). With the aim of obtaining a material with a more uniform structure, acid leaching was performed to remove the outer layer of brucite, resulting in a silicon oxide hydrate. This material was used as support for the deposition of Nb 2 O 5 .nH 2 O. The Nb 2 O 5 .nH 2 O was prepared by conventional precipitation using as starting material niobium metallic. In this study, we performed the synthesis and characterization of the material SiO 2 .nH 2 O / Nb 2 O 5 .nH 2 O 1:1. Both chrysotile as niobium are widely available national resources, which confirms the economic viability of resource use. The materials studied were characterized by XRD, SEM and TG/DTG. (author)

Study of PDMS conformation in PDMS-based hybrid materials prepared by gamma irradiation

International Nuclear Information System (INIS)

Lancastre, J.J.H.; Fernandes, N.; Margaça, F.M.A.; Miranda Salvado, I.M.; Ferreira, L.M.; Falcão, A.N.; Casimiro, M.H.

2012-01-01

Polydimethylsiloxane-silicate based hybrid materials have recognized properties (high flexibility, low elastic modulus or high mechanical strength) for which there are a large number of applications in development, such as for the bioapplications field. The hybrids addressed in the present study were prepared by gamma irradiation of a mixture of polydimethylsiloxane (PDMS) with tetraethylorthosilicate (TEOS) and zirconium propoxide (PrZr) without addition of any solvent or other product. The materials are homogeneous, transparent, monolithic and flexible. The structure dependence on the PrZr content is addressed. A combination of X-ray diffraction (XRD) and Infrared Spectroscopy (IR) was used. The results reveal that the polymer in the hybrids prepared with PrZr, in a content≤5 wt%, shows a structure similar to that in the irradiated pure polymer sample. In these samples the presence of ordered polymer regions is clearly found. For samples prepared with higher content of Zr almost no ordered polymer regions are observed. The addition of PrZr plays an important role on polymer conformation in these hybrid materials. - Highlights: ► PDMS-based hybrid materials were prepared by γ-irradiation. ► FTIR, ATR/FT-IR and XRD techniques were used to characterize the materials. ► Changes in FTIR bands reflect growth of crosslinking network. ► Above certain Zr concentration regions of Zr-silicate oxide are formed. ► Zr content determines conformation of the polymer chain network.

Mathematical modeling of a biogenous filter cake and identification of oilseed material parameters

Directory of Open Access Journals (Sweden)

Očenášek J.

2009-12-01

Full Text Available Mathematical modeling of the filtration and extrusion process inside a linear compression chamber has gained a lot of attention during several past decades. This subject was originally related to mechanical and hydraulic properties of soils (in particular work of Terzaghi and later was this approach adopted for the modeling of various technological processes in the chemical industry (work of Shirato. Developed mathematical models of continuum mechanics of porous materials with interstitial fluid were then applied also to the problem of an oilseed expression. In this case, various simplifications and partial linearizations are introduced in models for the reason of an analytical or numerical solubility; or it is not possible to generalize the model formulation into the fully 3D problem of an oil expression extrusion with a complex geometry such as it has a screw press extruder.We proposed a modified model for the oil seeds expression process in a linear compression chamber. The model accounts for the rheological properties of the deformable solid matrix of compressed seed, where the permeability of the porous solid is described by the Darcy's law. A methodology of the experimental work necessary for a material parameters identification is presented together with numerical simulation examples.

Teach the Mathematics of Mathematicians

Directory of Open Access Journals (Sweden)

Peter Taylor

2018-04-01

Full Text Available The secondary-school mathematics curriculum is narrow in scope and technical in character; this is quite different from the nature of the discipline itself. As a result, it offers little inspiration to both students and teachers, and provides students with poor preparation for university mathematics courses and indeed for life. Over the past century, recently more than ever, there have been calls for change, for a curriculum that is true to the subject of mathematics as the creation and study of patterns and structures. While there are hopeful responses to this at the elementary level, there is almost nothing at the secondary level. Ironically, it is felt that in order to prepare students for university calculus, the secondary curriculum simply has to be what it is. This is a special case of a myth that needs to be destroyed.

Challenging Transitions and Crossing Borders: Preparing Novice Mathematics Teacher Educators to Support Novice K-12 Mathematics Teachers

Science.gov (United States)

Yow, Jan A.; Eli, Jennifer A.; Beisiegel, Mary; McCloskey, Andrea; Welder, Rachael M.

2016-01-01

Sixty-nine recently graduated doctoral students in mathematics education completed a survey to determine their perceptions of transitioning from a doctoral program into an academic position at an institution of higher education. Research literature for novice mathematics school teachers was also reviewed to document their experiences transitioning…

"Smart" Materials Based on Cellulose: A Review of the Preparations, Properties, and Applications.

Science.gov (United States)

Qiu, Xiaoyun; Hu, Shuwen

2013-02-28

Cellulose is the most abundant biomass material in nature, and possesses some promising properties, such as mechanical robustness, hydrophilicity, biocompatibility, and biodegradability. Thus, cellulose has been widely applied in many fields. "Smart" materials based on cellulose have great advantages-especially their intelligent behaviors in reaction to environmental stimuli-and they can be applied to many circumstances, especially as biomaterials. This review aims to present the developments of "smart" materials based on cellulose in the last decade, including the preparations, properties, and applications of these materials. The preparations of "smart" materials based on cellulose by chemical modifications and physical incorporating/blending were reviewed. The responsiveness to pH, temperature, light, electricity, magnetic fields, and mechanical forces, etc. of these "smart" materials in their different forms such as copolymers, nanoparticles, gels, and membranes were also reviewed, and the applications as drug delivery systems, hydrogels, electronic active papers, sensors, shape memory materials and smart membranes, etc. were also described in this review.

Method of preparing an electrode material of lithium-aluminum alloy

Science.gov (United States)

Settle, Jack L.; Myles, Kevin M.; Battles, James E.

1976-01-01

A solid compact having a uniform alloy composition of lithium and aluminum is prepared as a negative electrode for an electrochemical cell. Lithium losses during preparation are minimized by dissolving aluminum within a lithium-rich melt at temperatures near the liquidus temperatures. The desired alloy composition is then solidified and fragmented. The fragments are homogenized to a uniform composition by annealing at a temperature near the solidus temperature. After comminuting to fine particles, the alloy material can be blended with powdered electrolyte and pressed into a solid compact having the desired electrode shape. In the preparation of some electrodes, an electrically conductive metal mesh is embedded into the compact as a current collector.

Ceria/silicon carbide core–shell materials prepared by miniemulsion technique

Directory of Open Access Journals (Sweden)

Lars Borchardt

2011-09-01

Full Text Available For the first time we present the synthesis of CeO2/Si(OC core–shell particles prepared by the miniemulsion technique. The Si(OC core was obtained by means of a polycarbosilane precursor (SMP10, which was subsequently functionalized with ceria and pyrolyzed to the ceramic. The size of these particles could easily be adjusted by varying the surfactants and the surfactant concentration, or by the addition of comonomers. Hence particle sizes ranged from 100 to 1000 nm, tunable by the preparation conditions. All materials were characterized by photon cross correlation spectroscopy, scanning electron microscopy and elemental mapping investigations. Furthermore, first catalytic tests were carried out by temperature programmed oxidation (TPO of methane, and the activity of this material in lowering the onset temperature of methane combustion by 262 K was documented.

Integrating Universal Design and Response to Intervention in Methods Courses for General Education Mathematics Teachers

Science.gov (United States)

Buchheister, Kelley; Jackson, Christa; Taylor, Cynthia E.

2014-01-01

Traditionally, teacher education programs have placed little emphasis on preparing mathematics teachers to work with students who struggle in mathematics. Therefore, it is crucial that mathematics teacher educators explicitly prepare prospective teachers to instruct students who struggle with mathematics by providing strategies and practices that…

Mathematics for common entrance three (extension) answers

CERN Document Server

Alexander, Serena

2015-01-01

This book contains answers to all exercises featured in the accompanying textbook Mathematics for Common Entrance Three (Extension) , which provides essential preparation for Level 3 of the ISEB 13+ Mathematics exam, as well as for CASE and other scholarship exams. - Clean, clear layout for easy marking. - Includes examples of high-scoring answers with diagrams and workings. Also available to purchase from the Galore Park website www.galorepark.co.uk :. - Mathematics for Common Entrance Three (Extension). - Mathematics for Common Entrance One. - Mathematics for Common Entrance One Answers. - M

In-service and Pre-service Middle School Mathematics Teachers' Attitudes and Decisions Regarding Teaching Mathematics Using Mobile Phones

Directory of Open Access Journals (Sweden)

Wajeeh M. Daher

2014-10-01

Full Text Available Several researches examined students' mathematics learning using mobile phones, while very few researches examined mathematics teaching using this new educational tool. This research attempts to analyze in-service and pre-service teachers' attitudes and decisions regarding mathematics teaching with mobile phones using activity theory. More specifically, three case studies are analyzed in this research: One concerns an in-service teacher who used mobile phones in her class, the second case study involves a pre-service teacher who collaborated with the in-service teacher to teach mathematics lessons using mobile phones, and the third case study is about 15 pre-service teachers who were observers of the experiment but did not use mobile phones in their teaching. We held one-hour semi-structured interviews with the in-service teacher, with the leading pre-service teacher and with the group of other observer pre-service teachers. This happened three times during the academic year: at the beginning of the experiment, after three months and after it ended. The research findings indicate that different factors have an impact on the attitudes and decisions of the teacher: history of the teacher using technologies in teaching, perceptions of the teacher using technologies in teaching, community’s teacher, rules regulating the use of technologies in teaching mathematics, and division of labor. For example, questions as to who decides which technologies to use in the classroom and who should prepare the learning material for the students. Contradictions were identified in mathematics teachers' activity when utilizing mobile phones in their teaching. These contradictions hinder or slow such utilization. Community, especially its leading members, mediated and helped overcome the activity contradictions that arose throughout the experiment regarding the teaching processes in and/or out of the mathematics classroom.

Thermoplastic starch materials prepared from rice starch

International Nuclear Information System (INIS)

Pontes, Barbara R.B.; Curvelo, Antonio A.S.

2009-01-01

Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

A mathematical model and an approximate method for calculating the fracture characteristics of nonmetallic materials during laser cutting

Energy Technology Data Exchange (ETDEWEB)

Smorodin, F.K.; Druzhinin, G.V.

1991-01-01

A mathematical model is proposed which describes the fracture behavior of amorphous materials during laser cutting. The model, which is based on boundary layer equations, is reduced to ordinary differential equations with the corresponding boundary conditions. The reduced model is used to develop an approximate method for calculating the fracture characteristics of nonmetallic materials.

Engineering mathematics

CERN Document Server

Bird, John

2014-01-01

A practical introduction to the core mathematics required for engineering study and practiceNow in its seventh edition, Engineering Mathematics is an established textbook that has helped thousands of students to succeed in their exams.John Bird's approach is based on worked examples and interactive problems. This makes it ideal for students from a wide range of academic backgrounds as the student can work through the material at their own pace. Mathematical theories are explained in a straightforward manner, being supported by practical engineering examples and applications in order to ensure

CULTUROLOGICAL APPROACH AS METHODOLOGICAL BASIS OF MATHEMATICAL EDUCATION

Directory of Open Access Journals (Sweden)

Ye. A. Perminov

2017-01-01

literacy have the extreme humanitarian importance, since their existence either indirectly or sometimes directly influences quality of life of any person and society in general. The most in-demand, significant and obligatory thematic and methodological components of mathematical education are highlighted: mathematical modeling, discrete mathematics and computing processes. The principle of a cultural conformity and a harmonious combination of the culturological and artfundamentals of mathematical education are emphasized as the basic educational principles, the use of which is capable to improve and raise the level of mathematical culture of the Russian society on a new, higher position.The evidence from this study points towards the idea that effective functioning of the system of mathematical education is impossible without the qualified, well prepared staff who are not only professionals in the subject sphere, but also bearers of high pedagogical culture. Moral and ethical, communicative and individual, and personal components of pedagogical culture of a teacher-mathematician are characterized.Practical significance. The author is convinced that introduction of the proposed concept of mathematical education based on culturological approach to its contents and the organization will help to overcome the disproportions existing today in mathematical education between integration and subject differentiation of a training material, technologization of educational process and preservation of traditional methods of training, fundamentalization of knowledge and competence-based approach to it, etc.Materials of the publication can be useful for future and practising teachers of mathematics and allied sciences, as well as for other categories of the educators engaged in the organization and advance of mathematical education and promotion of mathematical knowledge.

Managing Mathematics: How Does Classroom Management Affect the Maintenance of High Cognitive Demand Tasks during Lessons with Standards-Based Instructional Materials?

Science.gov (United States)

Barriteau Phaire, Candace

2013-01-01

The teaching and learning of mathematics has been the subject of debate for over 30 years and the most recent reform efforts are in response to concerns regarding the mathematical competence of students in the United States (Ball, Hill, & Bass, 2005; Battista, 1994; Cavanagh, 2008). Standards-based Instructional Materials (SBIM) allows…

Applying Constructionism and Problem Based Learning for Developing Dynamic Educational Material for Mathematics At Undergraduate University Level

DEFF Research Database (Denmark)

Triantafyllou, Eva; Timcenko, Olga

2013-01-01

As a result of changes in society and education, assumptions about the knowledge of entrants to university have become obsolete. One area in which this seems to be true is mathematics. This paper presents our research aiming at tackling with this problem by developing digital educational material...... for mathematics education, which will be student-driven, dynamic, and multimodal. Our approach will be supported by the theories of Constructionism and PBL. The impact of its use will be evaluated in university settings. It is expected that the evaluation will demonstrate an improvement in student engagement...

Preparation and certification of Sargasso seaweed reference material

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Kensaku

1988-01-01

Sargasso seaweed reference material was prepared from Sargassum felvellum obtained from an unpolluted area in Japan. The sargasso samples were washed, freeze-dried, pulverized, sieved to pass a 80-mesh screen and finally homogenized. Collaborative studies on the elemental analysis of the sargasso reference material were performed using various analytical techniques. Certified values are provided for Ag, As, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Pb, Rb, Sr, V and Zn, based on results of determinations by at least three independent analytical techniques. Reference values are reported for Al, Br, Cl, Cr, Cs, Hg, I, P, S, Sb, Sc, Se, Ti and U. The sargasso certified reference material contains high levels of alkali metals, alkaline earth metals, I, Br, As and U, while the concentration of trace elements may be considered to be at the lower end of the range of reported values for marine brown algae. The sargasso sample will be of practical use in marine and environmental sciences as a certified reference material having an elemental composition close to background levels.

Planning and Preparing for Emergency Response to Transport Accidents Involving Radioactive Material. Safety Guide

International Nuclear Information System (INIS)

2009-01-01

This Safety Guide provides guidance on various aspects of emergency planning and preparedness for dealing effectively and safely with transport accidents involving radioactive material, including the assignment of responsibilities. It reflects the requirements specified in Safety Standards Series No. TS-R-1, Regulations for the Safe Transport of Radioactive Material, and those of Safety Series No. 115, International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources. Contents: 1. Introduction; 2. Framework for planning and preparing for response to accidents in the transport of radioactive material; 3. Responsibilities for planning and preparing for response to accidents in the transport of radioactive material; 4. Planning for response to accidents in the transport of radioactive material; 5. Preparing for response to accidents in the transport of radioactive material; Appendix I: Features of the transport regulations influencing emergency response to transport accidents; Appendix II: Preliminary emergency response reference matrix; Appendix III: Guide to suitable instrumentation; Appendix IV: Overview of emergency management for a transport accident involving radioactive material; Appendix V: Examples of response to transport accidents; Appendix VI: Example equipment kit for a radiation protection team; Annex I: Example of guidance on emergency response to carriers; Annex II: Emergency response guide.

Preparation of nanocrystalline iron-carbon materials as fillers for polymers

International Nuclear Information System (INIS)

Narkiewicz, U; Pelech, I; Roslaniec, Z; Kwiatkowska, M; Arabczyk, W

2007-01-01

This paper presents a method of preparing nanocrystalline iron-carbon materials which can be applied as fillers for polymers. Nanocrystalline iron samples were carburized either under ethylene/hydrogen mixture or under pure ethylene. Three kinds of samples were prepared: cementite/carbon (Fe 3 C/C), iron/cementite (Fe/Fe 3 C) and iron/carbon (Fe/C) ones. After carburization the samples were characterized using XRD and SEM methods. The obtained samples of iron-carbon nanoparticles were applied as fillers to polymer nanocomposites prepared in a polycondensation reaction (in situ) in a poly(ether-ester) matrix. The nanofillers were dispersed in monomers (diols) using a sonificator and a high-speed rotary stirrer. The obtained nanocomposites were characterized as regards their structure (SEM method) and mechanical behaviour

Mathematical Biology Modules Based on Modern Molecular Biology and Modern Discrete Mathematics

Science.gov (United States)

Davies, Robin; Hodge, Terrell; Enyedi, Alexander

2010-01-01

We describe an ongoing collaborative curriculum materials development project between Sweet Briar College and Western Michigan University, with support from the National Science Foundation. We present a collection of modules under development that can be used in existing mathematics and biology courses, and we address a critical national need to introduce students to mathematical methods beyond the interface of biology with calculus. Based on ongoing research, and designed to use the project-based-learning approach, the modules highlight applications of modern discrete mathematics and algebraic statistics to pressing problems in molecular biology. For the majority of projects, calculus is not a required prerequisite and, due to the modest amount of mathematical background needed for some of the modules, the materials can be used for an early introduction to mathematical modeling. At the same time, most modules are connected with topics in linear and abstract algebra, algebraic geometry, and probability, and they can be used as meaningful applied introductions into the relevant advanced-level mathematics courses. Open-source software is used to facilitate the relevant computations. As a detailed example, we outline a module that focuses on Boolean models of the lac operon network. PMID:20810955

Mathematical biology modules based on modern molecular biology and modern discrete mathematics.

Science.gov (United States)

Robeva, Raina; Davies, Robin; Hodge, Terrell; Enyedi, Alexander

2010-01-01

We describe an ongoing collaborative curriculum materials development project between Sweet Briar College and Western Michigan University, with support from the National Science Foundation. We present a collection of modules under development that can be used in existing mathematics and biology courses, and we address a critical national need to introduce students to mathematical methods beyond the interface of biology with calculus. Based on ongoing research, and designed to use the project-based-learning approach, the modules highlight applications of modern discrete mathematics and algebraic statistics to pressing problems in molecular biology. For the majority of projects, calculus is not a required prerequisite and, due to the modest amount of mathematical background needed for some of the modules, the materials can be used for an early introduction to mathematical modeling. At the same time, most modules are connected with topics in linear and abstract algebra, algebraic geometry, and probability, and they can be used as meaningful applied introductions into the relevant advanced-level mathematics courses. Open-source software is used to facilitate the relevant computations. As a detailed example, we outline a module that focuses on Boolean models of the lac operon network.

Thermoelectric properties and nanostructures of materials prepared from rice husk ash

Energy Technology Data Exchange (ETDEWEB)

Pukird, S.; Tipparach, U.; Kasian, P. [Ubon Ratchathani Univ., Ubon Ratchathani (Thailand). Dept. of Physics; Limsuwan, P. [King Mongkut' s Univ. of Technology Thonburi, Bangkok (Thailand). Dept. of Physics

2009-07-01

Thailand produces large amounts of agricultural residues such as rice husk and coconut shells. Rice husk is considered to be a potential source for solar grade silicon. Studies have shown that reasonably pure polycrystalline silicon can be prepared from rice husk white ash by a metallothermic reduction process. This paper reported on a study that investigated the thermoelectric properties of ceramic material prepared by mixing silica from rice husk ash and carbon obtained from coconut shell charcoal. The thermoelectric properties of the materials were examined along with their microstructures. The materials were made from burning rice husk ash and coconut shell at different temperatures and then doped with metal oxides. Pellets were heated at temperature of 700 degrees C for 1-3 hours. The voltage on both sides of the pellets was observed. The electromotive force was found when different temperatures were applied on both sides of the pellet specimens. The Seebeck coefficient was then calculated. The results showed that these materials can be used as thermoelectric devices. Scanning electron microscope (SEM) and energy dispersive X-rays (EDX) were used to investigate the source of materials and the products on the substrates. The images of SEM and EDX showed nanostructures of materials such as nanowires, nanorods and nanoparticles of the products and sources. 22 refs., 2 tabs., 9 figs.

University of Toronto mathematics competition (2001–2015)

CERN Document Server

Barbeau, Edward J

2016-01-01

This text records the problems given for the first 15 annual undergraduate mathematics competitions, held in March each year since 2001 at the University of Toronto. Problems cover areas of single-variable differential and integral calculus, linear algebra, advanced algebra, analytic geometry, combinatorics, basic group theory, and number theory. The problems of the competitions are given in chronological order as presented to the students. The solutions appear in subsequent chapters according to subject matter. Appendices recall some background material and list the names of students who did well. The University of Toronto Undergraduate Competition was founded to provide additional competition experience for undergraduates preparing for the Putnam competition, and is particularly useful for the freshman or sophomore undergraduate. Lecturers, instructors, and coaches for mathematics competitions will find this presentation useful. Many of the problems are of intermediate difficulty and relate to the first two...

Understanding and responding the students in learning mathematics through the differentiated instruction

Science.gov (United States)

Hapsari, T.; Darhim; Dahlan, J. A.

2018-05-01

This research discusses the differentiated instruction, a mathematic learning which is as expected by the students in connection with the differentiated instruction itself, its implementation, and the students’ responses. This research employs a survey method which involves 62 students as the research respondents. The mathematics learning types required by the students and their responses to the differentiated instruction are examined through questionnaire and interview. The mathematics learning types in orderly required by the students, from the highest frequency cover the easily understood instructions, slowly/not rushing teaching, fun, not complicated, interspersed with humour, various question practices, not too serious, and conducive class atmosphere for the instructions. Implementing the differentiated instruction is not easy. The teacher should be able to constantly assess the students, s/he should have good knowledge of relevant materials and instructions, and properly prepare the instructions, although it is time-consuming. The differentiated instruction is implemented on the instructions of numerical pattern materials. The strategies implemented are flexible grouping, tiered assignment, and compacting. The students positively respond the differentiated learning instruction that they become more motivated and involved in the instruction.

Preparation and characterization of nano hydroxyapatite/polymeric composites materials. Part I

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Khaled R., E-mail: kh_rezk1966@yahoo.com [Biomaterials Dept., National Research Centre, Dokki, Cairo (Egypt); El-Rashidy, Zenab M. [Biomaterials Dept., National Research Centre, Dokki, Cairo (Egypt); Salama, Aida A. [Biophysics Dept., Faulty of Science, El-Azhar Univ., Cairo (Egypt)

2011-10-17

Highlights: {yields} The formation and coating of CHA increased by increasing polymer content. {yields} The size of the prepared CHA was within nano-range scale. {yields} The composites had homogeneity and CHA formed within the polymeric matrix. - Abstract: The present study is focused on preparation of nano composite materials and the effect of citric acid on their different properties. The formation of nano HA and its interaction with chitosan (C), gelatin (G) polymers and citric acid (CA) materials were studied. The Fourier Transformed Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM), and scanning electron microscope (SEM) were used to characterize these composite materials. The compressive strength (CS) was also measured to know the reinforcement of the prepared composites. The results show that carboxylic and amino groups play crucial role for HA formation on chitosan-gelatin polymeric matrix in the presence of citric acid (CA). The formation of nano HA particles and its average size of crystallite is increased with increase of CG content and decreased with addition of CA. Also, the HA formation and binding strength between its particles are improved into the composites especially with CA. The nano-composites containing the best ratio of nHA (70%) with CA (0.2 M) are promising for medical applications in the future.

Preparation in and Use of the Nemeth Braille Code for Mathematics by Teachers of Students with Visual Impairments

Science.gov (United States)

Rosenblum, L. Penny; Amato, Sheila

2004-01-01

This study examined the preparation in and use of the Nemeth braille code by 135 teachers of students with visual impairments. Almost all the teachers had taken at least one course in the Nemeth code as part of their university preparation. In their current jobs, they prepared a variety of materials, primarily basic operations, word problems,…

Method for selecting raw materials to preparing ceramic masses: application to raw material for red ceramic

International Nuclear Information System (INIS)

Moreno, Maria Margarita Torres; Rocha, Rogers Raphael da; Zanard, Antenor

2012-01-01

We studied the raw materials used in a factory building blocks, located in Cesario Lange city (SP). It extracts raw materials from various sources in the region to make the dough. The mixtures were prepared from dry milled powders based on data related to the plasticity of the raw materials. It was obtained with the apparatus Vicat-cone in order to obtain similar levels of water absorption of the samples burned at 900 deg C for all compositions. To quantify the proportion of each clay was used the Lever Rule. In this firing temperature, where sintering is mainly by diffusion from a solid state, different compositions of the same set of four raw materials resulted in similar values. (author)

Advanced Research Projects Agency on Materials Preparation and Characterization Research

Science.gov (United States)

Briefly summarized is research concerned with such topics as: Preparation of silica glass from amorphous silica; Glass structure by Raman ...ferroelectrics; Silver iodide crystals; Vapor phase growth; Refractory optical host materials; Hydroxyapatite ; Calcite; Characterization of single crystals with a double crystal spectrometer; Characterization of residual strain.

Particle size studies in the preparation of AQCS reference materials

International Nuclear Information System (INIS)

Fajgelj, A.; Zeisler, R.; Benesch, T.; Dekner, R.

1994-01-01

Particle size determination is one of the important steps in the characterization of physical properties of each particulate material. However, particle size distribution effects also a chemical composition of the material in terms of homogeneity and representativeness of the sample, as well as allows or not a possible sub-sampling of the material. All this is of great importance in the preparation of reference materials for which the chemical composition and physical properties have to be extremely well characterized. In the present paper we intend to present same efforts which have been done by Analytical Quality Control Services (AQCS) of the International Atomic Energy Agency (IAEA) in the field of particle size determination in the production of reference materials. The Malvern product MasterSizer X, based on laser light scattering is used for this purpose and the technique is also shortly discussed. (author)

Development and validation of science, technology, engineering and mathematics (STEM) based instructional material

Science.gov (United States)

Gustiani, Ineu; Widodo, Ari; Suwarma, Irma Rahma

2017-05-01

This study is intended to examine the development and validation of simple machines instructional material that developed based on Science, Technology, Engineering and Mathematics (STEM) framework that provides guidance to help students learn and practice for real life and enable individuals to use knowledge and skills they need to be an informed citizen. Sample of this study consist of one class of 8th grader at a junior secondary school in Bandung, Indonesia. To measure student learning, a pre-test and post-test were given before and after implementation of the STEM based instructional material. In addition, a questionnaire of readability was given to examine the clarity and difficulty level of each page of instructional material. A questionnaire of students' response towards instructional material given to students and teachers at the end of instructional material reading session to measure layout aspects, content aspects and utility aspects of instructional material for being used in the junior secondary school classroom setting. The results show that readability aspect and students' response towards STEM based instructional material of STEM based instructional material is categorized as very high. Pretest and posttest responses revealed that students retained significant amounts information upon completion of the STEM instructional material. Student overall learning gain is 0.67 which is categorized as moderate. In summary, STEM based instructional material that was developed is valid enough to be used as educational materials necessary for conducting effective STEM education.

Preparation and certification of a uranium isotope certified reference material JAERI-U5

International Nuclear Information System (INIS)

Tamura, Shuzo; Hashitani, Hiroshi

1982-06-01

The Committee on Analytical Chemistry of Nuclear Fuels and Reactor Materials, JAERI had planned to prepare a new reference material, JAERI-U5 for uranium isotopic measurement since 1978. The reference material is composed of 6 samples of different enrichment in the range of 0.2 to 4.5 wt. percents of 235 U. The preparation includes dissolution of raw materials, blending of solutions, precipitation of ammonium diuranate, drying and ignition to U 3 O 8 . A mass-spectrometric collaborative analysis was carried out by well-trained two laboratories in this country, JAERI and PNC. The certified values were decided from the result of the collaborative work. As the measurements were based on NBS SRM's, JAERI-U5 should be called tertiary standard. The materials are packed in bottles of low-potassium-content glass for a possible use in non-destructive gamma-rays spectrometry. The reference material has been distributing from JAERI with a price of yen 140,000 per set (6 samples of 2 g of each) since 1979. (author)

Preparation and properties of thin films treatise on materials science and technology

CERN Document Server

Tu, K N

1982-01-01

Treatise on Materials Science and Technology, Volume 24: Preparation and Properties of Thin Films covers the progress made in the preparation of thin films and the corresponding study of their properties. The book discusses the preparation and property correlations in thin film; the variation of microstructure of thin films; and the molecular beam epitaxy of superlattices in thin film. The text also describes the epitaxial growth of silicon structures (thermal-, laser-, and electron-beam-induced); the characterization of grain boundaries in bicrystalline thin films; and the mechanical properti

“Smart” Materials Based on Cellulose: A Review of the Preparations, Properties, and Applications

Science.gov (United States)

Qiu, Xiaoyun; Hu, Shuwen

2013-01-01

Cellulose is the most abundant biomass material in nature, and possesses some promising properties, such as mechanical robustness, hydrophilicity, biocompatibility, and biodegradability. Thus, cellulose has been widely applied in many fields. “Smart” materials based on cellulose have great advantages—especially their intelligent behaviors in reaction to environmental stimuli—and they can be applied to many circumstances, especially as biomaterials. This review aims to present the developments of “smart” materials based on cellulose in the last decade, including the preparations, properties, and applications of these materials. The preparations of “smart” materials based on cellulose by chemical modifications and physical incorporating/blending were reviewed. The responsiveness to pH, temperature, light, electricity, magnetic fields, and mechanical forces, etc. of these “smart” materials in their different forms such as copolymers, nanoparticles, gels, and membranes were also reviewed, and the applications as drug delivery systems, hydrogels, electronic active papers, sensors, shape memory materials and smart membranes, etc. were also described in this review. PMID:28809338

“Smart” Materials Based on Cellulose: A Review of the Preparations, Properties, and Applications

Directory of Open Access Journals (Sweden)

Shuwen Hu

2013-02-01

Full Text Available Cellulose is the most abundant biomass material in nature, and possesses some promising properties, such as mechanical robustness, hydrophilicity, biocompatibility, and biodegradability. Thus, cellulose has been widely applied in many fields. “Smart” materials based on cellulose have great advantages—especially their intelligent behaviors in reaction to environmental stimuli—and they can be applied to many circumstances, especially as biomaterials. This review aims to present the developments of “smart” materials based on cellulose in the last decade, including the preparations, properties, and applications of these materials. The preparations of “smart” materials based on cellulose by chemical modifications and physical incorporating/blending were reviewed. The responsiveness to pH, temperature, light, electricity, magnetic fields, and mechanical forces, etc. of these “smart” materials in their different forms such as copolymers, nanoparticles, gels, and membranes were also reviewed, and the applications as drug delivery systems, hydrogels, electronic active papers, sensors, shape memory materials and smart membranes, etc. were also described in this review.

Preparation of in-house graphite reference material for boron

International Nuclear Information System (INIS)

Kumar, Sanjukta A.; Venkatesh, K.; Swain, Kallola K.; Manisha, V.; Kamble, Granthali S.; Pandey, Shailaja P.; Remya Devi, P.S.; Ghosh, M.; Verma, R.

2016-05-01

Graphite is extensively used in nuclear technology. Boron concentration in graphite is one of the important parameters that decide its acceptability for nuclear applications. Reliable analytical methods are essential for the determination of boron in graphite at concentration about 5 mg kg -1 . Reference materials are used for validation of existing analytical methods and developing new methodologies. In view of the importance of determination of boron in graphite and unavailability of graphite reference material, an In-house graphite reference material was prepared in Analytical Chemistry Division. Graphite source material was procured, processed to obtain powder of ≤ 75 μm (200 mesh) and bottled. Procedures were developed for the determination of boron in graphite using inductively coupled plasma optical emission spectrometry (ICPOES) and inductively coupled plasma mass spectrometry (ICPMS) techniques. Homogeneity testing was carried out on the bottled units and boron content along with the combined and expanded uncertainties were established. The assigned boron concentration in the In-house graphite reference material is (7.3±0.46) mg kg -1 . (author)

Materials Preparation Center

Data.gov (United States)

Federal Laboratory Consortium — MPC is recognized throughout the worldwide research community for its unique capabilities in purification, preparation, and characterization of: rare earth metals,...

The Education of Mathematics

Directory of Open Access Journals (Sweden)

Abu Darda

2016-01-01

Full Text Available The objective of mathematics education is not only preparingmathematicians but making well-informed citizens. This is a broad generalterms for objective of the teaching of mathematics. And, this might beimplemented as “accurate thorough knowledge” or “original logicalthinking”. So, teaching mathematics is not the conversation andtransmission of mathematical knowledge, but on the aim of preparing wellinformedcitizens trained in independent, critical thinking.By the mathematics, sciences become simple, clearer, and easier to bedeveloped. The mathematics is often applied for solving any problem ofother field of sciences, either in the physics such as astronomy, chemistry,technique; or social sciences such as economy, demography, and assurance.Those all need an analysis reading ability.Mathematical skill, therefore, relates strongly with the analysisreading ability in the human intellectual structure. This study is about therelationship between them. And, result of the study shows us as below:Both Mathematical skill and analysis reading ability possess the “high type”of thinking operation. Both also involve the same content of the abstractintelligent, i.e. symbolic and semantic contents. Last but not least, both alsouse the same product of thinking, i.e. units, classes, relations, and systems.Both can be transformed and have an implication.

Basic considerations for the preparation of performance testing materials as related to performance evaluation acceptance criteria

International Nuclear Information System (INIS)

McCurdy, D.E.; Morton, J.S.

2001-01-01

The preparation of performance testing (PT) materials for environmental and radiobioassay applications involves the use of natural matrix materials containing the analyte of interest, the addition (spiking) of the analyte to a desired matrix (followed by blending for certain matrices) or a combination of the two. The distribution of the sample analyte concentration in a batch of PT samples will reflect the degree of heterogeneity of the analyte in the PT material and/or the reproducibility of the sample preparation process. Commercial and government implemented radioanalytical performance evaluation programs have a variety of acceptable performance criteria. The performance criteria should take into consideration many parameters related to the preparation of the PT materials including the within and between sample analyte heterogeneity, the accuracy of the quantification of an analyte in the PT material and to what 'known' value will a laboratory's result be compared. How sample preparation parameters affect the successful participation in performance evaluation (PE) programs having an acceptance criteria established as a percent difference from a 'known' value or in PE programs using other acceptance criteria, such as the guidance provided in ANSI N42.22 and N13.30 is discussed. (author)

Preparation of SnO2/C biomorphic materials by biotemplating from ...

Indian Academy of Sciences (India)

the micro-fine structure of the natural biological materials, but also is endowed ... nated with Sn(OH)4 sol using ultrasonic technique. The ... The mechanism of preparation has been .... tracheid structure of ramie fibres, and the orientation of the.

Composite Materials with Magnetically Aligned Carbon Nanoparticles and Methods of Preparation

Science.gov (United States)

Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

2018-01-01

The present invention relates to magnetically aligned carbon nanoparticle composites and methods of preparing the same. The composites comprise carbon nanoparticles, host material, magnetically sensitive nanoparticles and surfactant. The composites may have enhanced mechanical, thermal, and/or electrical properties.

Use of mathematical modelling in electron beam processing: A guidebook

International Nuclear Information System (INIS)

2010-01-01

The use of electron beam irradiation for industrial applications, like the sterilization of medical devices or cross-linking of polymers, has a long and successful track record and has proven itself to be a key technology. Emerging fields, including environmental applications of ionizing radiation, the sterilization of complex medical and pharmaceutical products or advanced material treatment, require the design and control of even more complex irradiators and irradiation processes. Mathematical models can aid the design process, for example by calculating absorbed dose distributions in a product, long before any prototype is built. They support process qualification through impact assessment of process variable uncertainties, and can be an indispensable teaching tool for technologists in training in the use of radiation processing. The IAEA, through various mechanisms, including its technical cooperation programme, coordinated research projects, technical meetings, guidelines and training materials, is promoting the use of radiation technologies to minimize the effects of harmful contaminants and develop value added products originating from low cost natural and human made raw materials. The need to publish a guidebook on the use of mathematical modelling for design processes in the electron beam treatment of materials was identified through the increased interest of radiation processing laboratories in Member States and as a result of recommendations from several IAEA expert meetings. In response, the IAEA has prepared this report using the services of an expert in the field. This publication should serve as both a guidebook and introductory tutorial for the use of mathematical modelling (using mostly Monte Carlo methods) in electron beam processing. The emphasis of this guide is on industrial irradiation methodologies with a strong reference to existing literature and applicable standards. Its target audience is readers who have a basic understanding of electron

[Preparation of sodium alginate-nanohydroxyapatite composite material for bone repair and its biocompatibility].

Science.gov (United States)

Wang, Yanmei; He, Jiacai; Li, Quanli; Shen, Jijia

2014-02-01

To prepare sodium alginate-nanohydroxyapatite composite material and to explore its feasibility as a bone repair material. Sodium alginate-nanohydroxyapatite composite material was prepared using chemical cross-linking and freeze-drying technology. The composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and its porosity was measured by liquid displacement method. The fifth passage of bone marrow stromal stem cells (BMSCs) were incubated on the composite material and then growth was observed by inverted microscope and SEM. BMSCs were cultured with liquid extracts of the material, methyl thiazolyl tetrazolium (MTT) assay was used to calculate the relative growth rate (RGR) on 1, 3, 5 d and to evaluate the cytotoxicity. Fresh dog blood was added into the liquid extracts to conduct hemolysis test, the spectrophotometer was used to determine the optical density (OD) and to calculate the hemolysis rate. Sodium alginate-nanohydroxyapatite composite material displayed porosity, the porous pore rate was (88.6 +/- 4.5)%. BMSCs showed full stretching and vigorous growth under inverted microscope and SEM. BMSCs cultured with liquid extracts of the material had good activities. The toxicity of composite material was graded as 1. Hemolysis test results showed that the hemolysis rate of the composite material was 1.28%, thus meeting the requirement of medical biomaterials. The composite material fabricated in this study has high porosity and good biocompatibility.

A MATHEMATICAL MODEL OF OPTIMIZATION OF THE VOLUME OF MATERIAL FLOWS IN GRAIN PROCESSING INTEGRATED PRODUCTION SYSTEMS

OpenAIRE

Baranovskaya T. P.; Loyko V. I.; Makarevich O. A.; Bogoslavskiy S. N.

2014-01-01

The article suggests a mathematical model of optimization of the volume of material flows: the model for the ideal conditions; the model for the working conditions; generalized model of determining the optimal input parameters. These models optimize such parameters of inventory management in technology-integrated grain production systems, as the number of cycles supply, the volume of the source material and financial flows. The study was carried out on the example of the integrated system of ...

Preparation of steel slag porous sound-absorbing material using coal powder as pore former.

Science.gov (United States)

Sun, Peng; Guo, Zhancheng

2015-10-01

The aim of the study was to prepare a porous sound-absorbing material using steel slag and fly ash as the main raw material, with coal powder and sodium silicate used as a pore former and binder respectively. The influence of the experimental conditions such as the ratio of fly ash, sintering temperature, sintering time, and porosity regulation on the performance of the porous sound-absorbing material was investigated. The results showed that the specimens prepared by this method had high sound absorption performance and good mechanical properties, and the noise reduction coefficient and compressive strength could reach 0.50 and 6.5MPa, respectively. The compressive strength increased when the dosage of fly ash and sintering temperature were raised. The noise reduction coefficient decreased with increasing ratio of fly ash and reducing pore former, and first increased and then decreased with the increase of sintering temperature and time. The optimum preparation conditions for the porous sound-absorbing material were a proportion of fly ash of 50% (wt.%), percentage of coal powder of 30% (wt.%), sintering temperature of 1130°C, and sintering time of 6.0hr, which were determined by analyzing the properties of the sound-absorbing material. Copyright © 2015. Published by Elsevier B.V.

Preparation and thermal conductivity enhancement of composite phase change materials for electronic thermal management

International Nuclear Information System (INIS)

Wu, Weixiong; Zhang, Guoqing; Ke, Xiufang; Yang, Xiaoqing; Wang, Ziyuan; Liu, Chenzhen

2015-01-01

Highlights: • A kind of composite phase change material board (PCMB) is prepared and tested. • PCMB presents a large thermal storage capacity and enhanced thermal conductivity. • PCMB displays much better cooling effect in comparison to natural air cooling. • PCMB presents different cooling characteristics in comparison to ribbed radiator. - Abstract: A kind of phase change material board (PCMB) was prepared for use in the thermal management of electronics, with paraffin and expanded graphite as the phase change material and matrix, respectively. The as-prepared PCMB presented a large thermal storage capacity of 141.74 J/g and enhanced thermal conductivity of 7.654 W/(m K). As a result, PCMB displayed much better cooling effect in comparison to natural air cooling, i.e., much lower heating rate and better uniformity of temperature distribution. On the other hand, compared with ribbed radiator technology, PCMB also presented different cooling characteristics, demonstrating that they were suitable for different practical application

Applied mathematics for science and engineering

CERN Document Server

Glasgow, Larry A

2014-01-01

Prepare students for success in using applied mathematics for engineering practice and post-graduate studies moves from one mathematical method to the next sustaining reader interest and easing the application of the techniques Uses different examples from chemical, civil, mechanical and various other engineering fields Based on a decade's worth of the authors lecture notes detailing the topic of applied mathematics for scientists and engineers Concisely writing with numerous examples provided including historical perspectives as well as a solutions manual for academic adopters

Tracking Developmental Students into Their First College Level Mathematics Course

Science.gov (United States)

Waycaster, Pansy

2011-01-01

A recent SACS review at the author's institution prompted an assessment of the school's developmental mathematics program. The author needed to examine the effectiveness of the developmental mathematics courses in preparing students for their first college level mathematics course. Rather than just examine success rates in developmental…

Preparation of standard hair material and development of analytical methodology

International Nuclear Information System (INIS)

Gangadharan, S.; Ganapathi Iyer, S.; Ali, M.M.; Thantry, S.S.; Verma, R.; Arunachalam, J.; Walvekar, A.P.

1992-01-01

In 1976 Indian Researchers suggested the possible use of hair as an indicator of environmental exposure and established through a study of country wide student population and general population of the metropolitan city of Bombay that human scalp hair could indeed be an effective first level monitor in a scheme of multilevel monitoring of environmental exposure to inorganic pollutants. It was in this context and in view of the ready availability of large quantities of scalp hair subjected to minimum treatment by chemicals that they proposed to participate in the preparation of a standard material of hair. It was also recognized that measurements of trace element concentrations at very low levels require cross-validation by different analytical techniques, even within the same laboratory. The programme of work that has been carried out since the first meeting of the CRP had been aimed at these two objectives. These objectives include the preparation of standard material of hair and the development of analytical methodologies for determination of elements and species of interest. 1 refs., 3 tabs

Hexamethyldisilazane Removal with Mesoporous Materials Prepared from Calcium Fluoride Sludge.

Science.gov (United States)

Kao, Ching-Yang; Lin, Min-Fa; Nguyen, Nhat-Thien; Tsai, Hsiao-Hsin; Chang, Luh-Maan; Chen, Po-Han; Chang, Chang-Tang

2018-05-01

A large amount of calcium fluoride sludge is generated by the semiconductor industry every year. It also requires a high amount of fuel consumption using rotor concentrators and thermal oxidizers to treat VOCs. The mesoporous adsorbent prepared by calcium fluoride sludge was used for VOCs treatment. The semiconductor industry employs HMDS to promote the adhesion of photo-resistant material to oxide(s) due to the formation of silicon dioxide, which blocks porous adsorbents. The adsorption of HMDS (Hexamethyldisiloxane) was tested with mesoporous silica materials synthesized from calcium fluoride (CF-MCM). The resulting samples were characterized by XRD, XRF, FTIR, N2-adsorption-desorption techniques. The prepared samples possessed high specific surface area, large pore volume and large pore diameter. The crystal patterns of CF-MCM were similar with Mobil composite matter (MCM-41) from TEM image. The adsorption capacity of HMDS with CF-MCM was 40 and 80 mg g-1, respectively, under 100 and 500 ppm HMDS. The effects of operation parameters, such as contact time and mixture concentration, on the performance of CF-MCM were also discussed in this study.

Research trends in mathematics teacher education

CERN Document Server

Lo, Jane-Jane; Zoest, Laura RVan

2014-01-01

Research on the preparation and continued development of mathematics teachers is becoming an increasingly important subset of mathematics education research. Such research explores the attributes, knowledge, skills and beliefs of mathematics teachers as well as methods for assessing and developing these critical aspects of teachers and influences on teaching.Research Trends in Mathematics Teacher Education focuses on three major themes in current mathematics teacher education research: mathematical knowledge for teaching, teacher beliefs and identities, and tools and techniques to support teacher learning. Through careful reports of individual research studies and cross-study syntheses of the state of research in these areas, the book provides insights into teachers' learning processes and how these processes can be harnessed to develop effective teachers. Chapters investigate bedrock skills needed for working with primary and secondary learners (writing relevant problems, planning lessons, being attentive to...

A Mixed Methods Study of Teach for America Teachers' Mathematical Beliefs, Knowledge, and Classroom Teaching Practices during a Reform-Based University Mathematics Methods Course

Science.gov (United States)

Swars, Susan Lee

2015-01-01

This mixed methods study examined the mathematical preparation of elementary teachers in a Teach for America (TFA) program, focal participants for whom there is scant extant research. Data collection occurred before and after a university mathematics methods course, with a particular focus on the participants' (n = 22) mathematical beliefs,…

Novel polymeric nanocomposites and porous materials prepared using organogels

International Nuclear Information System (INIS)

Lai, Wei-Chi; Tseng, Shen-Chen

2009-01-01

We propose a new method for preparing polymeric nanocomposites and porous materials using self-assembled templates formed by 1,3:2,4-dibenzylidene sorbitol (DBS) organogels. DBS is capable of self-assembling into a 3D nanofibrillar network at relatively low concentrations in some organic solvents to produce organogels. In this study, we induced the formation of such physical cross-linked networks in styrene. Subsequently, we polymerized the styrene in the presence of chemical cross-linkers, divinyl benzene (DVB), with different amounts of DBS using thermal-initiated polymerization. The resulting materials were transparent, homogeneous polystyrene (PS) nanocomposites with both physical and chemical cross-links. The porous polymeric materials were obtained by solvent extraction of the DBS nanofibrils from the PS. Brunauer-Emmett-Teller (BET) measurements show that the amounts of DBS and DVB influenced the specific surface area after the removal of the DBS fibrils.

Novel polymeric nanocomposites and porous materials prepared using organogels

Energy Technology Data Exchange (ETDEWEB)

Lai, Wei-Chi; Tseng, Shen-Chen, E-mail: wclai@mail.tku.edu.t [Department of Chemical and Materials Engineering, Tamkang University, 151 Ying-chuan Road, Tamsui, Taipei 25137, Taiwan (China)

2009-11-25

We propose a new method for preparing polymeric nanocomposites and porous materials using self-assembled templates formed by 1,3:2,4-dibenzylidene sorbitol (DBS) organogels. DBS is capable of self-assembling into a 3D nanofibrillar network at relatively low concentrations in some organic solvents to produce organogels. In this study, we induced the formation of such physical cross-linked networks in styrene. Subsequently, we polymerized the styrene in the presence of chemical cross-linkers, divinyl benzene (DVB), with different amounts of DBS using thermal-initiated polymerization. The resulting materials were transparent, homogeneous polystyrene (PS) nanocomposites with both physical and chemical cross-links. The porous polymeric materials were obtained by solvent extraction of the DBS nanofibrils from the PS. Brunauer-Emmett-Teller (BET) measurements show that the amounts of DBS and DVB influenced the specific surface area after the removal of the DBS fibrils.

Written feedback to mathematics homework

OpenAIRE

Žitko, Urša

2017-01-01

This diploma thesis is about teachers’ feedback to students’ mathematics homework. In the theoretical part I present the purpose and history of homework assignments as well as various classifications of types of homework. In general, homework assignments are intended for students to learn and refresh the subject matter they have learnt in class, to gain further understanding, to practice various mathematical processes, and to prepare the student for a forthcoming subject matter. By doing home...

Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials

International Nuclear Information System (INIS)

Zhang, Jianhua; Tao, Cuilian; Zhu, Yufang; Zhu, Min; Li, Jie; Hanagata, Nobutaka

2013-01-01

We have prepared multifunctional magnetic mesoporous Fe–CaSiO 3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO 3 materials were investigated. Mesoporous Fe–CaSiO 3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO 3 materials, mesoporous Fe–CaSiO 3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO 3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO 3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO 3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia. (paper)

APPLYING PROFESSIONALLY ORIENTED PROBLEMS OF MATHEMATICAL MODELING IN TEACHING STUDENTS OF ENGINEERING DEPARTMENTS

Directory of Open Access Journals (Sweden)

Natal’ya Yur’evna Gorbunova

2017-06-01

Full Text Available We described several aspects of organizing student research work, as well as solving a number of mathematical modeling problems: professionally-oriented, multi-stage, etc. We underlined the importance of their economic content. Samples of using such problems in teaching Mathematics at agricultural university were given. Several questions connected with information material selection and peculiarities of research problems application were described. Purpose. The author aims to show the possibility and necessity of using professionally-oriented problems of mathematical modeling in teaching Mathematics at agricultural university. The subject of analysis is including such problems into educational process. Methodology. The main research method is dialectical method of obtaining knowledge of finding approaches to selection, writing and using mathematical modeling and professionally-oriented problems in educational process; the methodology is study of these methods of obtaining knowledge. Results. As a result of analysis of literature, students opinions, observation of students work, and taking into account personal teaching experience, it is possible to make conclusion about importance of using mathematical modeling problems, as it helps to systemize theoretical knowledge, apply it to practice, raise students study motivation in engineering sphere. Practical implications. Results of the research can be of interest for teachers of Mathematics in preparing Bachelor and Master students of engineering departments of agricultural university both for theoretical research and for modernization of study courses.

Sampling, storage and sample preparation procedures for X ray fluorescence analysis of environmental materials

International Nuclear Information System (INIS)

1997-06-01

X ray fluorescence (XRF) method is one of the most commonly used nuclear analytical technique because of its multielement and non-destructive character, speed, economy and ease of operation. From the point of view of quality assurance practices, sampling and sample preparation procedures are the most crucial steps in all analytical techniques, (including X ray fluorescence) applied for the analysis of heterogeneous materials. This technical document covers recent modes of the X ray fluorescence method and recent developments in sample preparation techniques for the analysis of environmental materials. Refs, figs, tabs

Development of Methods of Preparing Materials for Teaching Machines: Professional Paper 29-68.

Science.gov (United States)

Skinner, B. F.; Zook, Lola M., Ed.

In the preparation of 12-inch disc teaching machine materials for elementary college courses, a preliminary analysis of subject matter and required skills precedes sequential framing. The programer must assess the beginning level of student competence and frame questions to supply new material until the proper response stands alone. Statements for…

Reutilization of discarded biomass for preparing functional polymer materials.

Science.gov (United States)

Wang, Jianfeng; Qian, Wenzhen; He, Yufeng; Xiong, Yubing; Song, Pengfei; Wang, Rong-Min

2017-07-01

Biomass is abundant and recyclable on the earth, which has been assigned numerous roles to human beings. However, over the past decades, accompanying with the rapid expansion of man-made materials, such as alloy, plastic, synthetic rubber and fiber, a great number of natural materials had been neglected and abandoned, such as straw, which cause a waste of resource and environmental pollution. In this review, based on introducing sources of discarded biomass, the main composition and polymer chains in discarded biomass materials, the traditional treatment and novel approach for reutilization of discarded biomass were summarized. The discarded biomass mainly come from plant wastes generated in the process of agriculture and forestry production and manufacturing processes, animal wastes generated in the process of animal husbandry and fishery production as well as the residual wastes produced in the process of food processing and rural living garbage. Compared with the traditional treatment including burning, landfill, feeding and fertilizer, the novel approach for reutilization of discarded biomass principally allotted to energy, ecology and polymer materials. The prepared functional materials covered in composite materials, biopolymer based adsorbent and flocculant, carrier materials, energy materials, smart polymer materials for medical and other intelligent polymer materials, which can effectively serve the environmental management and human life, such as wastewater treatment, catalyst, new energy, tissue engineering, drug controlled release, and coating. To sum up, the renewable and biodegradable discarded biomass resources play a vital role in the sustainable development of human society, as well as will be put more emphases in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Manufacture of high-strength composite materials from prepregs prepared by radiation processing

International Nuclear Information System (INIS)

Laricheva, V.P.; Korotkij, A.F.

2008-01-01

Scientific principles of the manufacture of high-strength heat-resistant polymer composite materials with the successive ionizing-radiation and heat treatment (via the step of long-lived prepregs) were developed. Methods for the selection of components for the preparation of long-lived prepregs, as well as for the determination of the optimal curing conditions, were proposed. The mechanical properties of the materials were studied [ru

Teaching Mathematics as Agape: Responding to Oppression with Unconditional Love

Science.gov (United States)

Amidon, Joel

2013-01-01

In this essay, encouraged by the critical examination of mathematics education and mathematics teacher education at the Privilege and Oppression in the Mathematics Preparation of Teacher Educators Conference, the author asks the question: What do I do from a position of power and privilege to interrupt oppression and enable everyone the…

Preparation and hygrothermal properties of composite phase change humidity control materials

International Nuclear Information System (INIS)

Chen, Zhi; Qin, Menghao

2016-01-01

Highlights: • A new kind of phase change humidity control material (PCHCM) was prepared. • The PCHCM can moderate both the indoor temperature and humidity. • The silicon dioxide shell can improve the thermal properties of the composite. • The PCM microcapsules can improve the moisture buffer ability of the composite. • The CPCM/vesuvianite composite has a better hygrothermal performance than pure hygroscopic material. - Abstract: A novel phase change humidity control material (PCHCM) was prepared by using PCM microcapsules and different hygroscopic porous materials. The PCHCM composite can regulate the indoor hygrothermal environment by absorbing or releasing both heat and moisture. The PCM microcapsules were synthesized with methyl triethoxysilane by the sol–gel method. The vesuvianite, sepiolite and zeolite were used as hygroscopic materials. The scanning electron microscopy (SEM) was used to measure the morphology profiles of the microcapsules and PCHCM. The differential scanning calorimetry (DSC) and the thermal gravimetric analysis (TGA) were used to determine the thermal properties and thermal stability. Both the moisture transfer coefficient and moisture buffer value (MBV) of different PCHCMs were measured by the improved cup method. The DSC results showed that the SiO 2 shell can reduce the super-cooling degree of PCM. The super-cooling degrees of microcapsules and PCHCM are lower than that of the pure PCM. The onset temperature of thermal degradation of the microcapsules and PCHCMs is higher than that of pure PCM. Both the moisture transfer coefficient and MBV of PCHCMs are higher than that of the pure hygroscopic materials. The results indicated the PCHCMs have better thermal properties and moisture buffer ability.

Construction mathematics

CERN Document Server

Virdi, Surinder; Virdi, Narinder Kaur

2014-01-01

Construction Mathematics is an introductory level mathematics text, written specifically for students of construction and related disciplines. Learn by tackling exercises based on real-life construction maths. Examples include: costing calculations, labour costs, cost of materials and setting out of building components. Suitable for beginners and easy to follow throughout. Learn the essential basic theory along with the practical necessities. The second edition of this popular textbook is fully updated to match new curricula, and expanded to include even more learning exercises. End of chapter exercises cover a range of theoretical as well as practical problems commonly found in construction practice, and three detailed assignments based on practical tasks give students the opportunity to apply all the knowledge they have gained. Construction Mathematics addresses all the mathematical requirements of Level 2 construction NVQs from City & Guilds/CITB and Edexcel courses, including the BTEC First Diploma in...

Preparation of resveratrol-loaded nanoporous silica materials with different structures

Science.gov (United States)

Popova, Margarita; Szegedi, Agnes; Mavrodinova, Vesselina; Novak Tušar, Natasa; Mihály, Judith; Klébert, Szilvia; Benbassat, Niko; Yoncheva, Krassimira

2014-11-01

Solid, nanoporous silica-based spherical mesoporous MCM-41 and KIL-2 with interparticle mesoporosity as well as nanosized zeolite BEA materials differing in morphology and pore size distribution, were used as carriers for the preparation of resveratrol-loaded delivery systems. Two preparation methods have been applied: (i) loading by mixing of resveratrol and mesoporous carrier in solid state and (ii) deposition in ethanol solution. The parent and the resveratrol loaded carriers were characterized by XRD, TEM, N2 physisorption, thermal analysis, and FT-IR spectroscopy. The influence of the support structure on the adsorption capacity and the release kinetics of this poorly soluble compound were investigated. Our results indicated that the chosen nanoporous silica supports are suitable for stabilization of trans-resveratrol and reveal controlled release and ability to protect the supported compound against degradation regardless of loading method. The solid-state dry mixing appears very effective for preparation of drug formulations composed of poorly soluble compound.

Mathematical Knowledge and Skills Expected by Higher Education in Engineering and the Social Sciences: Implications for High School Mathematics Curriculum

Science.gov (United States)

Basaran, Mehmet; Özalp, Gülümser; Kalender, Ilker; Alacaci, Cengiz

2015-01-01

One important function of school mathematics curriculum is to prepare high school students with the knowledge and skills needed for university education. Identifying them empirically will help making sound decisions about the contents of high school mathematics curriculum. It will also help students to make informed choices in course selection at…

Preparation and certification of trace mercury in water standard reference materials

International Nuclear Information System (INIS)

Moody, J.R.; Paulsen, P.J.; Rains, T.C.; Rook, H.L.

1976-01-01

The study of mercury in natural water supplies requires a Standard Reference Material (SRM) with a certified concentration at the 1 ng/g level. NBS SRM's have been prepared with nominal mercury concentrations of 1.5 μg/g and 1.2 ng/g. Confirmation of these values was obtained by neutron activation, atomic absorption, and isotope dilution-spark source mass spectrometry (IDSSMS). Nitric acid and trace amounts of gold were added to achieve a stable mercury concentration. The precautions observed for cleaning the glass and Teflon containers, preparation of mercury solutions, and the packaging of the SRM's are given. As an example of the care needed in the analysis of mercury at these levels, specific details are presented for the chemistry required to prepare samples for the spark source mass spectrometer

Preparation and characterization of a novel polymeric based solid-solid phase change heat storage material

International Nuclear Information System (INIS)

Xi Peng; Gu Xiaohua; Cheng Bowen; Wang Yufei

2009-01-01

Here we reported a two-step procedure for preparing a novel polymeric based solid-solid phase change heat storage material. Firstly, a copolymer monomer containing a polyethylene glycol monomethyl ether (MPEG) phase change unit and a vinyl unit was synthesized via the modification of hydrogen group of MPEG. Secondly, by copolymerization of the copolymer monomer and phenyl ethylene, a novel polymeric based solid-solid phase change heat storage material was prepared. The composition, structure and properties of the novel polymeric based solid-solid phase change material were characterized by IR, 1 H NMR, DSC, WAXD, and POM, respectively. The results show that the novel polymeric based solid-solid phase change material possesses of excellent crystal properties and high phase change enthalpy.

Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity.

Science.gov (United States)

Schwieger, Wilhelm; Machoke, Albert Gonche; Weissenberger, Tobias; Inayat, Amer; Selvam, Thangaraj; Klumpp, Michael; Inayat, Alexandra

2016-06-13

'Hierarchy' is a property which can be attributed to a manifold of different immaterial systems, such as ideas, items and organisations or material ones like biological systems within living organisms or artificial, man-made constructions. The property 'hierarchy' is mainly characterised by a certain ordering of individual elements relative to each other, often in combination with a certain degree of branching. Especially mass-flow related systems in the natural environment feature special hierarchically branched patterns. This review is a survey into the world of hierarchical systems with special focus on hierarchically porous zeolite materials. A classification of hierarchical porosity is proposed based on the flow distribution pattern within the respective pore systems. In addition, this review might serve as a toolbox providing several synthetic and post-synthetic strategies to prepare zeolitic or zeolite containing material with tailored hierarchical porosity. Very often, such strategies with their underlying principles were developed for improving the performance of the final materials in different technical applications like adsorptive or catalytic processes. In the present review, besides on the hierarchically porous all-zeolite material, special focus is laid on the preparation of zeolitic composite materials with hierarchical porosity capable to face the demands of industrial application.

VEDIC MATHEMATICS

Directory of Open Access Journals (Sweden)

Sead Rešić

2015-09-01

Full Text Available It is very difficult to motivate students when it comes to a school subject like Mathematics. Teachers spend a lot of time trying to find something that will arouse interest in students. It is particularly difficult to find materials that are motivating enough for students that they eagerly wait for the next lesson. One of the solutions may be found in Vedic Mathematics. Traditional methods of teaching Mathematics create fear of this otherwise interesting subject in the majority of students. Fear increases failure. Often the traditional, conventional mathematical methods consist of very long lessons which are difficult to understand. Vedic Mathematics is an ancient system that is very flexible and encourages the development of intuition and innovation. It is a mental calculating tool that does not require a calculator because the calculator is embedded in each of us. Starting from the above problems of fear and failure in Mathematics, the goal of this paper is to do research with the control and the experimental group and to compare the test results. Two tests should be done for each of the groups. The control group would do the tests in the conventional way. The experimental group would do the first test in a conventional manner and then be subjected to different treatment, that is to say, be taught on the basis of Vedic Mathematics. After that, the second group would do the second test according to the principles of Vedic Mathematics. Expectations are that after short lectures on Vedic mathematics results of the experimental group would improve and that students will show greater interest in Mathematics.

The Development of Geometri Teaching Materials Based on Constructivism to Improve the Students' Mathematic Reasoning Ability through Cooperative Learing Jigsaw at the Class VIII of SMP Negeri 3 Padangsidimpuan

Science.gov (United States)

Dewi, Izwita; Harahap, Muhammad Syahri

2016-01-01

The purposes of this research were to know the validity, practicality, and effectivity of geometrical learning material based on the constructivism to Increase students' mathematic reasoning ability and increasing students' mathematic reasoning ability by using learning material at the grade VIII of SMP Negeri 3 Padangsidimpuan. Type of the…

Advanced engineering mathematics

CERN Document Server

Jeffrey, Alan

2001-01-01

Advanced Engineering Mathematics provides comprehensive and contemporary coverage of key mathematical ideas, techniques, and their widespread applications, for students majoring in engineering, computer science, mathematics and physics. Using a wide range of examples throughout the book, Jeffrey illustrates how to construct simple mathematical models, how to apply mathematical reasoning to select a particular solution from a range of possible alternatives, and how to determine which solution has physical significance. Jeffrey includes material that is not found in works of a similar nature, such as the use of the matrix exponential when solving systems of ordinary differential equations. The text provides many detailed, worked examples following the introduction of each new idea, and large problem sets provide both routine practice, and, in many cases, greater challenge and insight for students. Most chapters end with a set of computer projects that require the use of any CAS (such as Maple or Mathematica) th...

Digital Materials Related to Food Science and　Cooking Methods for Preparing Eggs

OpenAIRE

沼田, 貴美子; 渡邉, 美奈; ヌマタ, キミコ; ワタナベ, ミナ; Numata, Kimiko; Watanabe, Mina

2009-01-01

We studied methods that were effective for teaching cooking to elementary school pupils using home economics materials. The subject was "Iritamago (scrambled eggs)". We researched the relationship between cookery science and experimental methods of making Iritamago. The various differences in condition and texture of Iritamago were compared among the different cooking utensils, conditions, and preparations of eggs. We created digital materials related to cookery science and the cooking method...

Material degradation due to moisture and temperature. Part 1: mathematical model, analysis, and analytical solutions

Science.gov (United States)

Xu, C.; Mudunuru, M. K.; Nakshatrala, K. B.

2016-11-01

The mechanical response, serviceability, and load-bearing capacity of materials and structural components can be adversely affected due to external stimuli, which include exposure to a corrosive chemical species, high temperatures, temperature fluctuations (i.e., freezing-thawing), cyclic mechanical loading, just to name a few. It is, therefore, of paramount importance in several branches of engineering—ranging from aerospace engineering, civil engineering to biomedical engineering—to have a fundamental understanding of degradation of materials, as the materials in these applications are often subjected to adverse environments. As a result of recent advancements in material science, new materials such as fiber-reinforced polymers and multi-functional materials that exhibit high ductility have been developed and widely used, for example, as infrastructural materials or in medical devices (e.g., stents). The traditional small-strain approaches of modeling these materials will not be adequate. In this paper, we study degradation of materials due to an exposure to chemical species and temperature under large strain and large deformations. In the first part of our research work, we present a consistent mathematical model with firm thermodynamic underpinning. We then obtain semi-analytical solutions of several canonical problems to illustrate the nature of the quasi-static and unsteady behaviors of degrading hyperelastic solids.

Mindset Matters: Supporting Student Persistence Through The Developmental Mathematics Pipeline

OpenAIRE

Kiser, Tracey Nicole

2016-01-01

Abstract of the DissertationMindset Matters: Supporting Student Persistence Through The Developmental Mathematics PipelinebyTracey Nicole KiserDoctor of Education in Teaching and LearningUniversity of California, San Diego, 2016Christopher P. Halter, ChairDevelopmental mathematics is one of the most challenging leaks in the mathematics K-20 pipeline. Few students enter two-year colleges prepared to successfully engage in college-level mathematics classes. Many of students who place into devel...

Biomolecular hybrid material and process for preparing same and uses for same

Science.gov (United States)

Kim, Jungbae [Richland, WA

2010-11-23

Disclosed is a composition and method for fabricating novel hybrid materials comprised of, e.g., carbon nanotubes (CNTs) and crosslinked enzyme clusters (CECs). In one method, enzyme-CNT hybrids are prepared by precipitation of enzymes which are subsequently crosslinked, yielding crosslinked enzyme clusters (CECs) on the surface of the CNTs. The CEC-enzyme-CNT hybrids exhibit high activity per unit area or mass as well as improved enzyme stability and longevity over hybrid materials known in the art. The CECs in the disclosed materials permit multilayer biocatalytic coatings to be applied to surfaces providing hybrid materials suitable for use in, e.g., biocatalytic applications and devices as described herein.

Mathematics for sustainability

CERN Document Server

Roe, John; Jamshidi, Sara

2018-01-01

Designed for the 21st century classroom, this textbook poses, refines, and analyzes questions of sustainability in a quantitative environment. Building mathematical knowledge in the context of issues relevant to every global citizen today, this text takes an approach that empowers students of all disciplines to understand and reason with quantitative information. Whatever conclusions may be reached on a given topic, this book will prepare the reader to think critically about their own and other people’s arguments and to support them with careful, mathematical reasoning. Topics are grouped in themes of measurement, flow, connectivity, change, risk, and decision-making. Mathematical thinking is at the fore throughout, as students learn to model sustainability on local, regional, and global scales. Exercises emphasize concepts, while projects build and challenge communication skills. With no prerequisites beyond high school algebra, instructors will find this book a rich resource for engaging all majors in the...

Coronal microleakage of four temporary restorative materials in Class II-type endodontic access preparations

Directory of Open Access Journals (Sweden)

Sang-Mi Yun

2012-02-01

Full Text Available Objectives The purpose of this study was to evaluate the microleakage of 4 temporary materials in teeth with Class II-type endodontic access preparations by using a glucose penetration model. Materials and Methods Glucose reaction test was performed to rule out the presence of any reaction between glucose and temporary material. Class II-type endodontic access preparations were made in extracted human premolars with a single root (n = 10. Each experimental group was restored with Caviton (GC, Spacer (Vericom, IRM (Dentsply-Caulk, or Fuji II(GC. Microleakage of four materials used as temporary restorative materials was evaluated by using a glucose penetration model. Data were analyzed by the one-way analysis of variance followed by a multiple-comparison Tukey test. The interface between materials and tooth were examined under a scanning electron microscope (SEM. Results There was no significant reaction between glucose and temporary materials used in this study. Microleakage was significantly lower for Caviton and Spacer than for Fuji II and IRM. SEM observation showed more intimate adaptation of tooth-restoration interfaces in Caviton and Spacer than in IRM and Fuji II. Conclusions Compared to IRM and Fuji II, Caviton and Spacer can be considered better temporary sealing materials in Class II-type endodontic access cavities.

Salt repository sealing materials development program: 5-year work plan

International Nuclear Information System (INIS)

Myers, L.B.

1986-06-01

This plan covers 5 years (fiscal years 1986 through 1990) of work in the repository sealing materials program to support design decisions and licensing activities for a salt repository. The plan covers a development activity, not a research activity. There are firm deliverables as the end points of each part of the work. The major deliverables are: development plans for code development and materials testing; seal system components models; seal system performance specifications; seal materials specifications; and seal materials properties ''handbook.'' The work described in this plan is divided into three general tasks as follows: mathematical modeling; materials studies (salt, cementitious materials, and earthen materials); and large-scale testing. Each of the sections presents an overview, status, planned activities, and summary of program milestones. This plan will be the starting point for preparing the development plans described above, but is subject to change if preparation of the work plan indicates that a different approach or sequence is preferable to achieve the ultimate goal, i.e., support of design and licensing

Further questions to the historiography of Arabic (but not only Arabic) mathematics from the perspective of Romance abbacus mathematics

DEFF Research Database (Denmark)

Høyrup, Jens

2007-01-01

Since some years I have been engaged in a close reading of early Italian abbacus books and related material from the Ibero-Provençal orbit and in comparison of this material with Arabic mathematical writings. At the 7th North African Meeting on the History of Arab Mathematics in Marrakesh in 2002...

PENGEMBANGAN RPP DAN LKPD BERBASIS REALISTIC MATHEMATICS EDUCATION DENGAN MEMERHATIKAN BEBAN KOGNITIF SISWA MATERI BANGUN RUANG SEDERHANA KELAS IV SD

Directory of Open Access Journals (Sweden)

Eko Waluyo

2016-12-01

Dalam suatu pembelajaran, dengan melibatkan siswa dalam menemukan suatu konsep materi matematika, siswa akan lebih mudah untuk memahami materi. Materi matematika dalam dipelajari dengan melibatkan obyek dunia nyata siswa sekolah dasar dengan memerhatikan beban kognitif siswa. Melalui bimbingan guru, siswa akan lebih mudah dalam menemukan konsep. Dalam tulisan ini dibahas pengembangan RPP dan LKPD berbasis Realistic Mathematics Education dengan memerhatikan beban kognitif siswa materi bangun ruang sederhana kelas IV SD. Model pengembangan yang digunakan model Plomp dengan lima fase. Hasil pengembangan RPP dan LKPD ini valid, praktis, dan efektif.

Sample preparation of energy materials for X-ray nanotomography with micromanipulation.

Science.gov (United States)

Chen-Wiegart, Yu-chen Karen; Camino, Fernando E; Wang, Jun

2014-06-06

X-ray nanotomography presents an unprecedented opportunity to study energy storage/conversion materials at nanometer scales in three dimensions, with both elemental and chemical sensitivity. A critical step in obtaining high-quality X-ray nanotomography data is reliable sample preparation to ensure that the entire sample fits within the field of view of the X-ray microscope. Although focused-ion-beam lift-out has previously been used for large sample (few to tens of microns) preparation, a difficult undercut and lift-out procedure results in a time-consuming sample preparation process. Herein, we propose a much simpler and direct sample preparation method to resolve the issues that block the view of the sample base after milling and during the lift-out process. This method is applied on a solid-oxide fuel cell and a lithium-ion battery electrode, before numerous critical 3D morphological parameters are extracted, which are highly relevant to their electrochemical performance. A broad application of this method for microstructure study with X-ray nanotomography is discussed and presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Model program for the recruitment and preparation of high ability elementary mathematics/science teachers: A collaborative project among scientists, teacher educators and classroom teachers

Energy Technology Data Exchange (ETDEWEB)

1993-12-01

This teacher education program will provide a model for recruiting, educating and retaining high ability students to become mathematics and science lead teachers in elementary schools. The quality experiences and support provided these students will help them develop the knowledge and attitudes necessary to provide leadership for elementary mathematics and science programs. Students will have research experiences at the Ames Laboratory, high quality field experiences with nationally recognized mathematics and science teachers in local schools and opportunities to meaningfully connect these two experiences. This program, collaboratively designed and implemented by scientists, teacher educators and classroom teachers, should provide a replicatable model for other teacher education institutions. In addition, materials developed for the project should help other laboratories interface more effectively with K-8 schools and help other teacher education programs incorporate real science and mathematics experience into their curriculum.

Relationship between teachers' coverage of mathematics curriculum ...

African Journals Online (AJOL)

kofi.mereku

African Journal of Educational Studies in Mathematics and Sciences Vol. ... materials (MCM) and their schools' performance in mathematics ... should be created for mathematics teachers in high performing junior high schools to share their ... in syllabuses which are also spread out in text books, teachers' hand out, etc.

Mathematical methods in material science and large scale optimization workshops: Final report, June 1, 1995-November 30, 1996

Energy Technology Data Exchange (ETDEWEB)

Friedman, A. [Minnesota Univ., Minneapolis, MN (United States). Inst. for Mathematics and Its Applications

1996-12-01

The summer program in Large Scale Optimization concentrated largely on process engineering, aerospace engineering, inverse problems and optimal design, and molecular structure and protein folding. The program brought together application people, optimizers, and mathematicians with interest in learning about these topics. Three proceedings volumes are being prepared. The year in Materials Sciences deals with disordered media and percolation, phase transformations, composite materials, microstructure; topological and geometric methods as well as statistical mechanics approach to polymers (included were Monte Carlo simulation for polymers); miscellaneous other topics such as nonlinear optical material, particulate flow, and thin film. All these activities saw strong interaction among material scientists, mathematicians, physicists, and engineers. About 8 proceedings volumes are being prepared.

HISTORY OF THE ENGINEERING PHYSICS AND MATHEMATICS DIVISION 1955-1993

Energy Technology Data Exchange (ETDEWEB)

Maskewitz, B.F.

2001-09-14

A review of division progress reports noting significant events and findings of the Applied Nuclear Physics, Neutron Physics, Engineering Physics, and then Engineering Physics and Mathematics divisions from 1955 to 1993 was prepared for use in developing a history of the Oak Ridge National Laboratory in celebration of its 50th year. The research resulted in an accumulation of historic material and photographs covering 38 years of effort, and the decision was made to publish a brief history of the division. The history begins with a detailed account of the founding of the Applied Nuclear Physics Division in 1955 and continues through the name change to the Neutron Physics Division in the late 1950s. The material thereafter is presented in decades--the sixties, seventies, and eighties--and ends as we enter the nineties.

Fundamentals of university mathematics

CERN Document Server

McGregor, C M; Stothers, W W

2010-01-01

The third edition of this popular and effective textbook provides in one volume a unified treatment of topics essential for first year university students studying for degrees in mathematics. Students of computer science, physics and statistics will also find this book a helpful guide to all the basic mathematics they require. It clearly and comprehensively covers much of the material that other textbooks tend to assume, assisting students in the transition to university-level mathematics.Expertly revised and updated, the chapters cover topics such as number systems, set and functions, differe

Preparation of a Carbon Doped Tissue-Mimicking Material with High Dielectric Properties for Microwave Imaging Application

Directory of Open Access Journals (Sweden)

Siang-Wen Lan

2016-07-01

Full Text Available In this paper, the oil-in-gelatin based tissue-mimicking materials (TMMs doped with carbon based materials including carbon nanotube, graphene ink or lignin were prepared. The volume percent for gelatin based mixtures and oil based mixtures were both around 50%, and the doping amounts were 2 wt %, 4 wt %, and 6 wt %. The effect of doping material and amount on the microwave dielectric properties including dielectric constant and conductivity were investigated over an ultra-wide frequency range from 2 GHz to 20 GHz. The coaxial open-ended reflection technology was used to evaluate the microwave dielectric properties. Six measured values in different locations of each sample were averaged and the standard deviations of all the measured dielectric properties, including dielectric constant and conductivity, were less than one, indicating a good uniformity of the prepared samples. Without doping, the dielectric constant was equal to 23 ± 2 approximately. Results showed with doping of carbon based materials that the dielectric constant and conductivity both increased about 5% to 20%, and the increment was dependent on the doping amount. By proper selection of doping amount of the carbon based materials, the prepared material could map the required dielectric properties of special tissues. The proposed materials were suitable for the phantom used in the microwave medical imaging system.

Research on risk assessment for maritime transport of radioactive materials. Preparation of maritime accident data for risk assessment

International Nuclear Information System (INIS)

Odano, Naoteru; Sawada, Ken-ichi; Mochiduki, Hiromitsu; Hirao, Yoshihiro; Asami, Mitsufumi

2010-01-01

Maritime transport of radioactive materials has been playing an important role in the nuclear fuel cycle in Japan. Due to recent increase of transported radioactive materials and diversification of transport packages with enlargement of nuclear research, development and utilization, safety securement for maritime transport of radioactive materials is one of important issues in the nuclear fuel cycle. Based squarely on the current circumstances, this paper summarizes discussion on importance of utilization of results of risk assessment for maritime transport of radioactive materials. A plan for development of comprehensive methodology to assess risks in maritime transport of radioactive materials is also described. Preparations of database of maritime accident to be necessary for risk assessment are also summarized. The prepared data could be utilized for future quantitative risk assessment, such as the event trees and fault trees analyses, for maritime transport of radioactive materials. The frequency of severe accident that the package might be damaged is also estimated using prepared data. (author)

Computational experiment approach to advanced secondary mathematics curriculum

CERN Document Server

Abramovich, Sergei

2014-01-01

This book promotes the experimental mathematics approach in the context of secondary mathematics curriculum by exploring mathematical models depending on parameters that were typically considered advanced in the pre-digital education era. This approach, by drawing on the power of computers to perform numerical computations and graphical constructions, stimulates formal learning of mathematics through making sense of a computational experiment. It allows one (in the spirit of Freudenthal) to bridge serious mathematical content and contemporary teaching practice. In other words, the notion of teaching experiment can be extended to include a true mathematical experiment. When used appropriately, the approach creates conditions for collateral learning (in the spirit of Dewey) to occur including the development of skills important for engineering applications of mathematics. In the context of a mathematics teacher education program, this book addresses a call for the preparation of teachers capable of utilizing mo...

Preparation and thermal energy storage properties of paraffin/calcined diatomite composites as form-stable phase change materials

International Nuclear Information System (INIS)

Sun, Zhiming; Zhang, Yuzhong; Zheng, Shuilin; Park, Yuri; Frost, Ray L.

2013-01-01

Highlights: ► Composite phase change material (PCM) was prepared by blending composite paraffin and calcined diatomite. ► The optimum mixed proportion was obtained through differential scanning calorimetry. ► Thermal energy storage properties of the composite PCMs were determined by DSC. ► Thermal cycling test showed that the prepared PCMs are thermally reliable and chemically stable. - Abstract: A composite paraffin-based phase change material (PCM) was prepared by blending composite paraffin and calcined diatomite through the fusion adsorption method. In this study, raw diatomite was purified by thermal treatment in order to improve the adsorption capacity of diatomite, which acted as a carrier material to prepare shape-stabilized PCMs. Two forms of paraffin (paraffin waxes and liquid paraffin) with different melting points were blended together by the fusion method, and the optimum mixed proportion with a suitable phase-transition temperature was obtained through differential scanning calorimetry (DSC) analysis. Then the prepared composite paraffin was adsorbed in calcined diatomite. The prepared paraffin/calcined diatomite composites were characterized by the scanning electron microscope (SEM) and Fourier transformation infrared (FT-IR) analysis techniques. Thermal energy storage properties of the composite PCMs were determined by DSC method. DSC results showed that there was an optimum adsorption ratio between composite paraffin and calcined diatomite and the phase-transition temperature and the latent heat of the composite PCMs were 33.04 °C and 89.54 J/g, respectively. Thermal cycling test of composite PCMs showed that the prepared material is thermally reliable and chemically stable. The obtained paraffin/calcined diatomite composites have proper latent heat and melting temperatures, and show practical significance and good potential application value

Preparation and thermal energy storage properties of paraffin/calcined diatomite composites as form-stable phase change materials

Energy Technology Data Exchange (ETDEWEB)

Sun, Zhiming [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Zhang, Yuzhong [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Zheng, Shuilin, E-mail: shuilinzh@yahoo.com.cn [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Park, Yuri [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Frost, Ray L., E-mail: r.frost@qut.edu.au [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia)

2013-04-20

Highlights: ► Composite phase change material (PCM) was prepared by blending composite paraffin and calcined diatomite. ► The optimum mixed proportion was obtained through differential scanning calorimetry. ► Thermal energy storage properties of the composite PCMs were determined by DSC. ► Thermal cycling test showed that the prepared PCMs are thermally reliable and chemically stable. - Abstract: A composite paraffin-based phase change material (PCM) was prepared by blending composite paraffin and calcined diatomite through the fusion adsorption method. In this study, raw diatomite was purified by thermal treatment in order to improve the adsorption capacity of diatomite, which acted as a carrier material to prepare shape-stabilized PCMs. Two forms of paraffin (paraffin waxes and liquid paraffin) with different melting points were blended together by the fusion method, and the optimum mixed proportion with a suitable phase-transition temperature was obtained through differential scanning calorimetry (DSC) analysis. Then the prepared composite paraffin was adsorbed in calcined diatomite. The prepared paraffin/calcined diatomite composites were characterized by the scanning electron microscope (SEM) and Fourier transformation infrared (FT-IR) analysis techniques. Thermal energy storage properties of the composite PCMs were determined by DSC method. DSC results showed that there was an optimum adsorption ratio between composite paraffin and calcined diatomite and the phase-transition temperature and the latent heat of the composite PCMs were 33.04 °C and 89.54 J/g, respectively. Thermal cycling test of composite PCMs showed that the prepared material is thermally reliable and chemically stable. The obtained paraffin/calcined diatomite composites have proper latent heat and melting temperatures, and show practical significance and good potential application value.

What Benefits Could Extension Papers and Admissions Tests Have for University Mathematics Applicants?

Science.gov (United States)

Darlington, Ellie

2015-01-01

It is well documented in both the British press and mathematics education literature that many consider A-levels (qualifications for secondary school leavers in England, Wales and Northern Ireland) to be insufficient preparation for undergraduate mathematics study in the UK. A-level Mathematics and Further Mathematics are not solely intended for…

Preparation of cathode materials for Li-ion cells by acid dissolution

International Nuclear Information System (INIS)

Oh, Si Hyoung; Jeong, Woon Tae; Cho, Won Il; Cho, Byung Won; Woo, Kyoungja

2005-01-01

New synthesis route called acid dissolution method, preparing the high-performance cathode materials for the lithium-ion cells, was successfully developed. In this method, insoluble starting materials such as metal carbonates or metal hydroxides are dissolved in strong organic acidic solution which contains a chelating agent. And then, the solvent of the solution containing starting materials is eliminated to obtain the xerogel of the initial solution whose chemical form is expressed as Li[MA 3 ], where M is a transition metal atom and A is the anion of the organic acid. The xerogel is then calcined at the high temperature to obtain polycrystalline cathode materials. In this work, the applicability of this method was demonstrated synthesizing a polycrystalline single-phase LiCoO 2 using lithium carbonate, cobalt hydroxide as the insoluble starting materials and the acrylic acid as a chelating agent. The synthesized powders calcined at 800 deg. C showed a good electrochemical performance in the half-cell test

Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

Science.gov (United States)

Linsheng, Li; Guoxiang, Lin; Lihui, Li

2016-08-12

In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity.

Two-dimensional mathematical model for simulation of the drying process of thick layers of natural materials in a conveyor-belt dryer

Directory of Open Access Journals (Sweden)

Salemović Duško R.

2017-01-01

Full Text Available This paper presents the mathematical model and numerical analysis of the convective drying process of thick slices of colloidal capillary-porous materials slowly moving through conveyor-belt dryer. A flow of hot moist air was used as drying agent. The drying process has been analyzed in the form of a 2-D mathematical model, in two directions: along the conveyor and perpendicular on it. The mathematical model consists of two non-linear differential equations and one equation with a transcendent character and it is based on the mathematical model developed for drying process in a form of a 1-D thin layer. The appropriate boundary conditions were introduced. The presented model is suitable for the automated control of conveyor-belt dryers. The obtained results with analysis could be useful in predicting the drying kinetics of potato slices and similar natural products.

New mathematical cuneiform texts

CERN Document Server

Friberg, Jöran

2016-01-01

This monograph presents in great detail a large number of both unpublished and previously published Babylonian mathematical texts in the cuneiform script. It is a continuation of the work A Remarkable Collection of Babylonian Mathematical Texts (Springer 2007) written by Jöran Friberg, the leading expert on Babylonian mathematics. Focussing on the big picture, Friberg explores in this book several Late Babylonian arithmetical and metro-mathematical table texts from the sites of Babylon, Uruk and Sippar, collections of mathematical exercises from four Old Babylonian sites, as well as a new text from Early Dynastic/Early Sargonic Umma, which is the oldest known collection of mathematical exercises. A table of reciprocals from the end of the third millennium BC, differing radically from well-documented but younger tables of reciprocals from the Neo-Sumerian and Old-Babylonian periods, as well as a fragment of a Neo-Sumerian clay tablet showing a new type of a labyrinth are also discussed. The material is presen...

The history of theoretical, material and computational mechanics mathematics meets mechanics and engineering

CERN Document Server

2014-01-01

This collection of 23 articles is the output of lectures in special sessions on “The History of Theoretical, Material and Computational Mechanics” within the yearly conferences of the GAMM in the years 2010 in Karlsruhe, Germany, 2011 in Graz, Austria, and in 2012 in Darmstadt, Germany; GAMM is the “Association for Applied Mathematics and Mechanics”, founded in 1922 by Ludwig Prandtl and Richard von Mises. The contributions in this volume discuss different aspects of mechanics. They are related to solid and fluid mechanics in general and to specific problems in these areas including the development of numerical solution techniques. In the first part the origins and developments of conservation principles in mechanics and related variational methods are treated together with challenging applications from the 17th to the 20th century. Part II treats general and more specific aspects of material theories of deforming solid continua and porous soils. and Part III presents important theoretical and enginee...

The mathematical theory of general relativity

CERN Document Server

Katkar, L N

2014-01-01

This book is prepared for M. Sc. Students of Mathematics and Physics. The aim of writing this book is to give the reader a feeling for the necessity and beauty of the laws of general relativity. The contents of the book will attract both mathematicians and physicists which provides motivation and applications of many ideas and powerful mathematical methods of modern analysis and differential geometry. An attempt has been made to make the presentation comprehensive, rigorous and yet simple. Most calculations and transformations have been carried out in great detail. KEY FEATURE: Numerous solved examples using the well known mathematical techniques viz., the tensors and the differential forms in each chapter.

Mathematical Background of Public Key Cryptography

DEFF Research Database (Denmark)

Frey, Gerhard; Lange, Tanja

2005-01-01

The two main systems used for public key cryptography are RSA and protocols based on the discrete logarithm problem in some cyclic group. We focus on the latter problem and state cryptographic protocols and mathematical background material.......The two main systems used for public key cryptography are RSA and protocols based on the discrete logarithm problem in some cyclic group. We focus on the latter problem and state cryptographic protocols and mathematical background material....

Automated SEM and TEM sample preparation applied to copper/low k materials

Science.gov (United States)

Reyes, R.; Shaapur, F.; Griffiths, D.; Diebold, A. C.; Foran, B.; Raz, E.

2001-01-01

We describe the use of automated microcleaving for preparation of both SEM and TEM samples as done by SELA's new MC500 and TEMstation tools. The MC500 is an automated microcleaving tool that is capable of producing cleaves with 0.25 μm accuracy resulting in SEM-ready samples. The TEMstation is capable of taking a sample output from the MC500 (or from SELA's earlier MC200 tool) and producing a FIB ready slice of 25±5 μm, mounted on a TEM-washer and ready for FIB thinning to electron transparency for TEM analysis. The materials selected for the tool set evaluation mainly included the Cu/TaN/HOSP low-k system. The paper is divided into three sections, experimental approach, SEM preparation and analysis of HOSP low-k, and TEM preparation and analysis of Cu/TaN/HOSP low-k samples. For the samples discussed, data is presented to show the quality of preparation provided by these new automated tools.

Discrete mathematics using a computer

CERN Document Server

Hall, Cordelia

2000-01-01

Several areas of mathematics find application throughout computer science, and all students of computer science need a practical working understanding of them. These core subjects are centred on logic, sets, recursion, induction, relations and functions. The material is often called discrete mathematics, to distinguish it from the traditional topics of continuous mathematics such as integration and differential equations. The central theme of this book is the connection between computing and discrete mathematics. This connection is useful in both directions: • Mathematics is used in many branches of computer science, in applica­ tions including program specification, datastructures,design and analysis of algorithms, database systems, hardware design, reasoning about the correctness of implementations, and much more; • Computers can help to make the mathematics easier to learn and use, by making mathematical terms executable, making abstract concepts more concrete, and through the use of software tools su...

American Mathematical Association of Two Year Colleges Reform Policies in Practice: Implementing Standards in Classroom Instruction for Basic Skills Mathematics at One Four-Year College in New Jersey

Science.gov (United States)

Garruto, Patricia J.

2012-01-01

High school graduates continue to enter post-secondary education lacking in basic mathematical skills and thus not academically prepared to enroll in college-level mathematics courses (ACT, 2010). Although it can be argued that those mathematical concepts should have been mastered in grades K-12, educating those students in basic skills…

Sol-gel Process in Preparation of Organic-inorganic Hybrid Materials

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Macan, J

2008-07-01

Full Text Available Organic-inorganic hybrid materials are a sort of nanostructured material in which the organic and inorganic phases are mixed at molecular level. The inorganic phase in hybrid materials is formed by the sol-gel process, which consists of reactions of hydrolysis and condensation of metal (usually silicon alkoxides. Flexibility of sol-gel process enables creation of hybrid materials with varying organic and inorganic phases in different ratios, and consequently fine-tuning of their properties. In order to obtain true hybrid materials, contact between the phases should be at molecular level, so phase separation between thermodynamically incompatible organic and inorganic phases has to be prevented. Phase interaction can be improved by formation of hydrogen or covalent bonds between them during preparation of hybrid materials. Covalent bond can be introduced by organically modified silicon alkoxides containing a reactive organic group (substituent capable of reacting with the organic phase. In order to obtain hybrid materials with desired structures, a detailed knowledge of hydrolysis and condensation mechanism is necessary. The choice of catalyst, whether acid or base, has the most significant influence on the structure of the inorganic phase. Other important parameters are alkoxide concentration, water: alkoxide ratio, type of alkoxide groups, solvent used, temperature, purity of chemicals used, etc. Hydrolysis and condensation of organically modified silicon alkoxides are additionally influenced by nature and size of the organic supstituent.

Transparency masters for mathematics revealed

CERN Document Server

Berman, Elizabeth

1980-01-01

Transparency Masters for Mathematics Revealed focuses on master diagrams that can be used for transparencies for an overhead projector or duplicator masters for worksheets. The book offers information on a compilation of master diagrams prepared by John R. Stafford, Jr., audiovisual supervisor at the University of Missouri at Kansas City. Some of the transparencies are designed to be shown horizontally. The initial three masters are number lines and grids that can be used in a mathematics course, while the others are adaptations of text figures which are slightly altered in some instances. The

Profiles of Opportunities to Learn for TEDS-M Future Secondary Mathematics Teachers

Science.gov (United States)

Wang, Ting-Ying; Tang, Shu-Jyh

2013-01-01

This study used the data set from the Teacher Education and Development Study in Mathematics to identify the profiles of opportunities to learn (OTL) regarding topics studied in teacher preparation programs by future secondary mathematics teachers from 15 participating countries. The topics of inquiry covered tertiary-level mathematics,…

Mathematical modelling of powder material motion and transportation in high-temperature flow core during plasma coatings application

Science.gov (United States)

Bogdanovich, V. I.; Giorbelidze, M. G.

2018-03-01

A problem of mathematical modelling of powder material motion and transportation in gas thermal flow core has been addressed. Undertaken studies indicate significant impact on dynamics of motion of sprayed particles of phenomenological law for drag coefficient and accounting momentum loss of a plasma jet upon acceleration of these particles and their diameter. It is determined that at great dispersion of spraying particles, they reach detail surface at different velocity and significant particles separation takes place at spraying spot. According to the results of mathematical modelling, requirements for admissible dispersion of diameters of particles used for spraying have been formulated. Research has also allowed reducing separation of particles at the spraying spot due to the selection of the method of powder feed to the anode channel of the plasma torch.

Group investigation with scientific approach in mathematics learning

Science.gov (United States)

Indarti, D.; Mardiyana; Pramudya, I.

2018-03-01

The aim of this research is to find out the effect of learning model toward mathematics achievement. This research is quasi-experimental research. The population of research is all VII grade students of Karanganyar regency in the academic year of 2016/2017. The sample of this research was taken using stratified cluster random sampling technique. Data collection was done based on mathematics achievement test. The data analysis technique used one-way ANOVA following the normality test with liliefors method and homogeneity test with Bartlett method. The results of this research is the mathematics learning using Group Investigation learning model with scientific approach produces the better mathematics learning achievement than learning with conventional model on material of quadrilateral. Group Investigation learning model with scientific approach can be used by the teachers in mathematics learning, especially in the material of quadrilateral, which is can improve the mathematics achievement.

The use of mathematical models in teaching wastewater treatment engineering

DEFF Research Database (Denmark)

Morgenroth, Eberhard Friedrich; Arvin, Erik; Vanrolleghem, P.

2002-01-01

Mathematical modeling of wastewater treatment processes has become increasingly popular in recent years. To prepare students for their future careers, environmental engineering education should provide students with sufficient background and experiences to understand and apply mathematical models...... efficiently and responsibly. Approaches for introducing mathematical modeling into courses on wastewater treatment engineering are discussed depending on the learning objectives, level of the course and the time available....

Mario Bunge's Philosophy of Mathematics: An Appraisal

Science.gov (United States)

Marquis, Jean-Pierre

2012-01-01

In this paper, I present and discuss critically the main elements of Mario Bunge's philosophy of mathematics. In particular, I explore how mathematical knowledge is accounted for in Bunge's systemic emergent materialism.

Secondary Schools Curriculum Guide, Mathematics, Grades 10-12. Revised.

Science.gov (United States)

Cranston School Dept., RI.

Behavioral objectives for grades 10 through 12 are specified for plane geometry, algebra, general mathematics, computer mathematics, slide rule mathematics, basic college mathematics, trigonometry, analytic geometry, calculus and probability. Most sections present material in terms of portions of a school year. At least one major objective is…

Preparation and Characterisation of LiFePO4/CNT Material for Li-Ion Batteries

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Rushanah Mohamed

2011-01-01

Full Text Available Li-ion battery cathode materials were synthesised via a mechanical activation and thermal treatment process and systematically studied. LiFePO4/CNT composite cathode materials were successfully prepared from LiFePO4 material. The synthesis technique involved growth of carbon nanotubes onto the LiFePO4 using a novel spray pyrolysis-modified CVD technique. The technique yielded LiFePO4/CNT composite cathode material displaying good electrochemical activity. The composite cathode exhibited excellent electrochemical performances with 163 mAh/g discharge capacity with 94% cycle efficiency at a 0.1 C discharge rate in the first cycle, with a capacity fade of approximately 10% after 30 cycles. The results indicate that carbon nanotube addition can enable LiFePO4 to display a higher discharge capacity at a fast rate with high efficiency. The research is of potential interest for the application of carbon nanotubes as a new conducting additive in cathode preparation and for the development of high-power Li-ion batteries for hybrid electric vehicles.

Optimization of Sample Preparation processes of Bone Material for Raman Spectroscopy.

Science.gov (United States)

Chikhani, Madelen; Wuhrer, Richard; Green, Hayley

2018-03-30

Raman spectroscopy has recently been investigated for use in the calculation of postmortem interval from skeletal material. The fluorescence generated by samples, which affects the interpretation of Raman data, is a major limitation. This study compares the effectiveness of two sample preparation techniques, chemical bleaching and scraping, in the reduction of fluorescence from bone samples during testing with Raman spectroscopy. Visual assessment of Raman spectra obtained at 1064 nm excitation following the preparation protocols indicates an overall reduction in fluorescence. Results demonstrate that scraping is more effective at resolving fluorescence than chemical bleaching. The scraping of skeletonized remains prior to Raman analysis is a less destructive method and allows for the preservation of a bone sample in a state closest to its original form, which is beneficial in forensic investigations. It is recommended that bone scraping supersedes chemical bleaching as the preferred method for sample preparation prior to Raman spectroscopy. © 2018 American Academy of Forensic Sciences.

Raising Public Awareness of Mathematics

CERN Document Server

Behrends, Ehrhard; Rodrigues, José Francisco

2012-01-01

This collective book aims to encourage and inspire actions directed towards raising public awareness of the importance of mathematical sciences for our contemporary society in a cultural and historical perspective. Mathematical societies, in Europe and around the world, can find ideas, blueprints and suggestions for activities - including concerted actions with other international organizations - directed towards raising public awareness of science, technology and other fields where mathematics plays a strong role. The material is divided into four parts: * National experiences * Exhibitions /

2nd International Conference on Mathematics and Statistics

CERN Document Server

Jarrah, Abdul; Kallel, Sadok; Sulieman, Hana

2017-01-01

This work presents invited contributions from the second "International Conference on Mathematics and Statistics" jointly organized by the AUS (American University of Sharjah) and the AMS (American Mathematical Society). Addressing several research fields across the mathematical sciences, all of the papers were prepared by faculty members at universities in the Gulf region or prominent international researchers. The current volume is the first of its kind in the UAE and is intended to set new standards of excellence for collaboration and scholarship in the region.

Comprehensive basic mathematics

CERN Document Server

Veena, GR

2005-01-01

Salient Features As per II PUC Basic Mathematics syllabus of Karnataka. Provides an introduction to various basic mathematical techniques and the situations where these could be usefully employed. The language is simple and the material is self-explanatory with a large number of illustrations. Assists the reader in gaining proficiency to solve diverse variety of problems. A special capsule containing a gist and list of formulae titled ''REMEMBER! Additional chapterwise arranged question bank and 3 model papers in a separate section---''EXAMINATION CORNER''.

Discrete algorithmic mathematics

CERN Document Server

Maurer, Stephen B

2005-01-01

The exposition is self-contained, complemented by diverse exercises and also accompanied by an introduction to mathematical reasoning … this book is an excellent textbook for a one-semester undergraduate course and it includes a lot of additional material to choose from.-EMS, March 2006In a textbook, it is necessary to select carefully the statements and difficulty of the problems … in this textbook, this is fully achieved … This review considers this book an excellent one.-The Mathematical Gazette, March 2006

Preparation of a new gamma irradiated PVC-Olive oil cake plastic composite material

International Nuclear Information System (INIS)

Messaud, F.A.; Almsmary, Y.A.; Elwerfalli, S.M.; Benayad, S.M.; Haraga, S.O.; Benfaid, N.A.; Kabar, Y.M.

2003-01-01

This paper dealt with the investigation on preparing new plastic composite material, utilizing polyvinyl chloride polymer (a commercial product in abu-kammash chemical complex) and olive oil cake (a waste of many olive oil production factories), followed by gamma irradiation (26.3 Kg ry) o induce crosslinking of the polymer. The new material possess good, electrical and mechanical properties as compared to plastic products of (PVC plastic pipe factory), and which could be used as new construction anti corrosive material, such as special roofing and partitioning or household goods

Preparation and structural characterization of the thermoluminescent material CaSO4: Dy

International Nuclear Information System (INIS)

Sanchez R, A.; Azorin, J.; Gonzalez M, P.R.; Rivera, T.

2005-01-01

The grade of crystallinity of a material is important so that the one is presented the thermoluminescence phenomenon; for what is necessary to study those structural characteristic of a TL material and to correlate them with its TL response when being irradiated with ionizing radiation. The calcium sulfate activated with Dysprosium (CaSO 4 : Dy) it is a material that has demonstrated its efficiency in the dosimetry of the ionizing radiation for the thermoluminescence method. In this work the structural characterization of this prepared material for the recrystallization method by means of the evaporation of the solvent and their relationship with their TL response is presented. The results showed that the best material to be used in thermoluminescent dosimetry presents a crystalline structure in orthorhombic phase and a particle size in the interval of 80 μm to 200 μm. (Author)

An introduction to mathematical cryptography

CERN Document Server

Hoffstein, Jeffrey; Silverman, Joseph H

2014-01-01

This self-contained introduction to modern cryptography emphasizes the mathematics behind the theory of public key cryptosystems and digital signature schemes. The book focuses on these key topics while developing the mathematical tools needed for the construction and security analysis of diverse cryptosystems. Only basic linear algebra is required of the reader; techniques from algebra, number theory, and probability are introduced and developed as required. This text provides an ideal introduction for mathematics and computer science students to the mathematical foundations of modern cryptography. The book includes an extensive bibliography and index; supplementary materials are available online. The book covers a variety of topics that are considered central to mathematical cryptography. Key topics include: classical cryptographic constructions, such as Diffie–Hellmann key exchange, discrete logarithm-based cryptosystems, the RSA cryptosystem, and digital signatures; fundamental mathematical tools for cr...

Preparation process and properties of LiCoO2/PANI/dodecylbenzenesulfonate composite electrode materials

International Nuclear Information System (INIS)

Ferchichi, Karima; Hbaieb, Souhaira; Amdouni, Noureddine; Kalfat, Rafik; Chevalier, Yves

2013-01-01

Composite materials that combine the lithium exchanging material LiCoO 2 and the conductive polymer poly(aniline) (PANI) have been investigated regarding their possible application to electrode materials of lithium batteries. Such composite materials have been prepared by means of polymerization of aniline in acidic suspensions of LiCoO 2 particles. PANI was synthesized by oxidative polymerization of aniline by ammonium persulfate in the presence of sodium dodecylbenzenesulfonate (SDBS) as a micellar template and dopant. The composite material consisted in LiCoO 2 particles dispersed in a continuous matrix of PANI. The ribbon-like morphology of the powdered material was distinctly different of the morphologies of the parent materials. The conductive material had conductivity close to that of PANI because the LiCoO 2 content of the composite material was low. The presence of the poorly conductive inorganic phase caused a significant loss of conductivity, showing that LiCoO 2 blocked electronic transfers between PANI crystallites. Ammonium persulfate caused the loss of lithium from LiCoO 2 when it was used at high concentration in the polymerization recipe. In this case a new phase made of Co 3 O 4 formed by chemical decomposition of Li x CoO 2 . Thin films prepared from stable suspensions of composite materials in water show comparable electrical performance to that measured for bulk materials. - Highlights: • LiCoO 2 was incorporated in a conductive polymer matrix made of PANI. • The hybrid material retained the high conductive properties of PANI. • Loss of lithium by persulfate oxidation caused conversion of LiCoO 2 into Co 3 O 4

What Is the Problem in Problem-Based Learning in Higher Education Mathematics

Science.gov (United States)

Dahl, Bettina

2018-01-01

Problem and Project-Based Learning (PBL) emphasise collaborate work on problems relevant to society and emphases the relation between theory and practice. PBL fits engineering students as preparation for their future professions but what about mathematics? Mathematics is not just applied mathematics, but it is also a body of abstract knowledge…

The Path to College Calculus: The Impact of High School Mathematics Coursework

Science.gov (United States)

Sadler, Philip; Sonnert, Gerhard

2018-01-01

This study addresses a longstanding question among high school mathematics teachers and college mathematics professors: Which is the best preparation for college calculus-- (a) a high level of mastery of mathematics considered preparatory for calculus (algebra, geometry, precalculus) or (b) taking calculus itself in high school? We used a data set…

A study of school mathematics curriculum enacted by competent teachers in Singapore secondary schools

Science.gov (United States)

Kaur, Berinderjeet; Tay, Eng Guan; Toh, Tin Lam; Leong, Yew Hoong; Lee, Ngan Hoe

2018-03-01

A study of school mathematics curriculum enacted by competent teachers in Singapore secondary schools is a programmatic research project at the National Institute of Education (NIE) funded by the Ministry of Education (MOE) in Singapore through the Office of Education Research (OER) at NIE. The main goal of the project is to collect a set of data that would be used by two studies to research the enacted secondary school mathematics curriculum. The project aims to examine how competent experienced secondary school teachers implement the designated curriculum prescribed by the MOE in the 2013 revision of curriculum. It does this firstly by examining the video recordings of the classroom instruction and interactions between secondary school mathematics teachers and their students, as it is these interactions that fundamentally determine the nature of the actual mathematics learning and teaching that take place in the classroom. It also examines content through the instructional materials used—their preparation, use in classroom and as homework. The project comprises a video segment and a survey segment. Approximately 630 secondary mathematics teachers and 600 students are participating in the project. The data collection for the video segment of the project is guided by the renowned complementary accounts methodology while the survey segment adopts a self-report questionnaire approach. The findings of the project will serve several purposes. They will provide timely feedback to mathematics specialists in the MOE, inform pre-service and professional development programmes for mathematics teachers at the NIE and contribute towards articulation of "Mathematics pedagogy in Singapore secondary schools" that is evidence based.

The Preparation Experiences of Elementary Mathematics Specialists: Examining Influences on Beliefs, Content Knowledge, and Teaching Practices

Science.gov (United States)

Swars, Susan L.; Smith, Stephanie Z.; Smith, Marvin E.; Carothers, Jody; Myers, Kayla

2018-01-01

Many in the field of mathematics education call for elementary schools to have elementary mathematics specialists (EMSs) who provide needed mathematical expertise and support for children and teachers. EMSs serve as a reasonable, immediate alternative to the challenges generated by elementary teachers needing improved mathematical knowledge for…

Preparation and certification of arsenate [As(V)] reference material, NMIJ CRM 7912-a.

Science.gov (United States)

Narukawa, Tomohiro; Kuroiwa, Takayoshi; Narushima, Izumi; Jimbo, Yasujiro; Suzuki, Toshihiro; Chiba, Koichi

2010-05-01

Arsenate [As(V)] solution reference material, National Metrology Institute of Japan (NMIJ) certified reference material (CRM) 7912-a, for speciation of arsenic species was developed and certified by NMIJ, the National Institute of Advanced Industrial Science and Technology. High-purity As(2)O(3) reagent powder was dissolved in 0.8 M HNO(3) solution and As(III) was oxidized to As(V) with HNO(3) to prepare 100 mg kg(-1) of As(V) candidate CRM solution. The solution was bottled in 400 bottles (50 mL each). The concentration of As(V) was determined by four independent analytical techniques-inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry, graphite furnace atomic absorption spectrometry, and liquid chromatography inductively coupled plasma mass spectrometry-according to As(V) calibration solutions, which were prepared from the arsenic standard of the Japan Calibration Service system and whose species was guaranteed to be As(V) by NMIJ. The uncertainties of all the measurements and preparation procedures were evaluated. The certified value of As(V) in the CRM is (99.53 +/- 1.67) mg kg(-1) (k = 2).

Initial Study on Thin Film Preparation of Carbon Nanodots Composites as Luminescence Material

Science.gov (United States)

Iskandar, F.; Aimon, A. H.; Akmaluddin, A. R.; Nuryadin, B. W.; Abdullah, M.

2016-08-01

Nowadays, the developments of phosphors materials require elements without noble metals and simple production process. Carbon nanodots (C-dots) are one of phosphor materials with wide range of emission band, and high biocompatibility. In this research thin film carbon nanodots composite have been prepared by spin coating method. Prior deposition, powder carbon nanodots were synthesized from a mixture of commercial urea as the nitrogen sources and citric acid as a carbon source by using hydrothermal and microwave-assisted heating method. The prepared powder was dispersed in transparent epoxy resin and then coated on glass substrate. The photoluminescence result for sample with 0.035 g citric acid exhibited an intense, single, homogeneous and broad spectrum with yellowish emission upon excitation at 365 nm. The Fourier Transform Infrared Spectroscopy (FTIR) result showed the existences of C=C, C-H, C=O, N-H and O-H functional groups which confirmed the quality of the sample. Further, based on UV-Vis measurement, the prepared thin film was highly transparent (transmittance 90%) with estimated film thickness around 764 nm. This result may open an opportunity for optoelectronic devices.

Initial Study on Thin Film Preparation of Carbon Nanodots Composites as Luminescence Material

International Nuclear Information System (INIS)

Iskandar, F; Aimon, A H; Akmaluddin, A R; Abdullah, M; Nuryadin, B W

2016-01-01

Nowadays, the developments of phosphors materials require elements without noble metals and simple production process. Carbon nanodots (C-dots) are one of phosphor materials with wide range of emission band, and high biocompatibility. In this research thin film carbon nanodots composite have been prepared by spin coating method. Prior deposition, powder carbon nanodots were synthesized from a mixture of commercial urea as the nitrogen sources and citric acid as a carbon source by using hydrothermal and microwave-assisted heating method. The prepared powder was dispersed in transparent epoxy resin and then coated on glass substrate. The photoluminescence result for sample with 0.035 g citric acid exhibited an intense, single, homogeneous and broad spectrum with yellowish emission upon excitation at 365 nm. The Fourier Transform Infrared Spectroscopy (FTIR) result showed the existences of C=C, C-H, C=O, N-H and O-H functional groups which confirmed the quality of the sample. Further, based on UV-Vis measurement, the prepared thin film was highly transparent (transmittance 90%) with estimated film thickness around 764 nm. This result may open an opportunity for optoelectronic devices. (paper)

MICROCT AND PREPARATION OF ß-TCP GRANULAR MATERIAL BY THE POLYURETHANE FOAM METHOD

Directory of Open Access Journals (Sweden)

Robert Filmon

2011-05-01

Full Text Available Commercial ß-tricalcium phosphate (ß-TCP is commercialy available in granules manufactured by sintering of powders. We have evaluated the different steps of the manufacturing process of ß-TCP ceramics granules prepared from blocks obtained with the polyurethane foam technology. Three types of slurry were prepared with 10, 15 and 25 g of ß-TCP per gram of polyurethane foam. Analysis was done by scanning electron microscopy, EDX, Raman spectroscopy and microcomputed tomography combined with image analysis. A special algorithm was used to identify the internal microporosity (created by the calcination of the foam from the internal macroporosity due to the spatial repartition of the material. The low ß-TCP dosages readily infiltrated the foam and the slurry was deposited along the polymer rods. On the contrary, the highest concentration produced inhomogeneous infiltrated blocks and foam cavities appeared completely filled in some areas. 2D microcomputed sections and reconstructed 3D models evidenced this phenomenon and the frequency distribution of the thickness and separation of material trabeculae confirmed the heterogeneity of the distribution. When crushed, blocks prepared with the 25 g slurry provided the largest and irregular granulates.

Porous Chromatographic Materials as Substrates for Preparing Synthetic Nuclear Explosion Debris Particles

International Nuclear Information System (INIS)

Harvey, Scott D.; Liezers, Martin; Antolick, Kathryn C.; Garcia, Ben J.; Sweet, Lucas E.; Carman, April J.; Eiden, Gregory C.

2013-01-01

In this study, we investigated several porous chromatographic materials as synthetic substrates for preparing surrogate nuclear explosion debris particles. The resulting synthetic debris materials are of interest for use in developing analytical methods. Eighteen metals, including some of forensic interest, were loaded onto materials by immersing them in metal solutions (556 mg/L of each metal) to fill the pores, applying gentle heat (110°C) to drive off water, and then treating them at high temperatures (up to 800°C) in air to form less soluble metal species. High-boiling-point metals were uniformly loaded on spherical controlled-pore glass to emulate early fallout, whereas low-boiling-point metals were loaded on core-shell silica to represent coated particles formed later in the nuclear fallout-formation process. Analytical studies were applied to characterize solubility, material balance, and formation of recalcitrant species. Dissolution experiments indicated loading was 1.5 to 3 times higher than expected from the pore volume alone, a result attributed to surface coating. Analysis of load solutions before and after filling the material pores revealed that most metals were passively loaded; that is, solutions filled the pores without active metal discrimination. However, niobium and tin concentrations were lower in solutions after pore filling, and were found in elevated concentrations in the final products, indicating some metals were selectively loaded. High-temperature treatments caused reduced solubility of several metal species, and loss of some metals (rhenium and tellurium) because volatile species were formed. Sample preparation reproducibility was high (the inter-batch relative standard deviation was 7.8%, and the intra-batch relative standard deviation was 0.84%) indicating that this material is suitable for use as a working standard for analytical methods development. We anticipate future standardized radionuclide-loaded materials will find use in

Lectures on constructive mathematical analysis

CERN Document Server

Kushner, B A

1984-01-01

The basis of this book was a special course given by the author at the Mechanics-Mathematics Faculty of Moscow University. The material presumes almost no previous knowledge and is completely understandable to a reader who is in command of a standard course of mathematical analysis. There are an extensive bibliography and indexes which will be helpful to students.

An excursion through elementary mathematics, volume iii discrete mathematics and polynomial algebra

CERN Document Server

Caminha Muniz Neto, Antonio

2018-01-01

This book provides a comprehensive, in-depth overview of elementary mathematics as explored in Mathematical Olympiads around the world. It expands on topics usually encountered in high school and could even be used as preparation for a first-semester undergraduate course. This third and last volume covers Counting, Generating Functions, Graph Theory, Number Theory, Complex Numbers, Polynomials, and much more. As part of a collection, the book differs from other publications in this field by not being a mere selection of questions or a set of tips and tricks that applies to specific problems. It starts from the most basic theoretical principles, without being either too general or too axiomatic. Examples and problems are discussed only if they are helpful as applications of the theory. Propositions are proved in detail and subsequently applied to Olympic problems or to other problems at the Olympic level. The book also explores some of the hardest problems presented at National and International Mathematics Ol...

The Effectiveness of the North Carolina Early Mathematics Placement Test in Preparing High School Students for College-Level Introductory Mathematics Courses

Science.gov (United States)

Hilgoe, Ellen; Brinkley, Jason; Hattingh, Johannes; Bernhardt, Robert

2016-01-01

Since its establishment in 1996, the North Carolina Early Mathematics Placement Testing (NC EMPT) Program has provided a low stakes reality check of readiness for college-level mathematics to more than 600,000 high school students statewide. The program strives to help reduce the percentage of incoming college freshmen requiring mathematics…

Evaluation and additional recommendations for preparing a whole blood control material

Directory of Open Access Journals (Sweden)

Nilda E. Fink

1998-04-01

Full Text Available OBJECTIVE: The assessment of an easy to prepare and low cost control material for Hematology, available for manual and automated methods. MATERIAL AND METHOD: Aliquots of stabilized whole blood were prepared by partial fixation with aldehydes; the stability at different temperatures (4. 20 and 37 °C during periods of up to 8-9 weeks and aliquot variability with both methods were controlled. RESULTS: Aliquot variability with automated methods at day 1, expressed as CV% (coefficient of variation was: white blood cells (WBC 2.7, red blood cells (RBC 0.7, hemoglobin (Hb 0.6, hematocrit (Hct 0.7, mean cell volume (MCV 0.3, mean cell hemoglobin (MCH 0.6, mean cell hemoglobin concentration (MCHC 0.7, and platelets (PLT 4.6. The CV (coefficient of variation percentages obtained with manual methods in one of the batches were: WBC 23, Hct 2.8, Hb 4.5, MCHC 5.9, PLT 41. Samples stored at 4ºC and 20ºC showed good stability, only a very low initial hemolysis being observed, whereas those stored at 37ºC deteriobed a rapidly (metahemoglobin formation, aggregation of WBC and platelets, as well as alteration of erythrocyte indexes. CONCLUSIONS: It was confirmed that, as long as there is no exposure to high temperatures during distribution, this material is stable, allowing assessment, both esternal and internal, for control purposes, with acceptable reproductivity, both for manual and auttomatic methods.

Application of mathematical model methods for optimization tasks in construction materials technology

Science.gov (United States)

Fomina, E. V.; Kozhukhova, N. I.; Sverguzova, S. V.; Fomin, A. E.

2018-05-01

In this paper, the regression equations method for design of construction material was studied. Regression and polynomial equations representing the correlation between the studied parameters were proposed. The logic design and software interface of the regression equations method focused on parameter optimization to provide the energy saving effect at the stage of autoclave aerated concrete design considering the replacement of traditionally used quartz sand by coal mining by-product such as argillite. The mathematical model represented by a quadric polynomial for the design of experiment was obtained using calculated and experimental data. This allowed the estimation of relationship between the composition and final properties of the aerated concrete. The surface response graphically presented in a nomogram allowed the estimation of concrete properties in response to variation of composition within the x-space. The optimal range of argillite content was obtained leading to a reduction of raw materials demand, development of target plastic strength of aerated concrete as well as a reduction of curing time before autoclave treatment. Generally, this method allows the design of autoclave aerated concrete with required performance without additional resource and time costs.

Mathematics for physicists

CERN Document Server

Dennery, Philippe

1967-01-01

""A fine example of how to present 'classical' physical mathematics."" - American ScientistWritten for advanced undergraduate and graduate students, this volume provides a thorough background in the mathematics needed to understand today's more advanced topics in physics and engineering. Without sacrificing rigor, the authors develop the theoretical material at length, in a highly readable, and, wherever possible, in an intuitive manner. Each abstract idea is accompanied by a very simple, concrete example, showing the student that the abstraction is merely a generalization from easily understo

Fifty Years of A-Level Mathematics: Have Standards Changed?

Science.gov (United States)

Jones, Ian; Wheadon, Chris; Humphries, Sara; Inglis, Matthew

2016-01-01

Advanced-level (A-level) mathematics is a high-profile qualification taken by many school leavers in England, Wales, Northern Ireland and around the world as preparation for university study. Concern has been expressed in these countries that standards in A-level mathematics have declined over time, and that school leavers enter university or the…

Porous Materials from Thermally Activated Kaolinite: Preparation, Characterization and Application

Directory of Open Access Journals (Sweden)

Jun Luo

2017-06-01

Full Text Available In the present study, porous alumina/silica materials were prepared by selective leaching of silicon/aluminum constituents from thermal-activated kaolinite in inorganic acid or alkali liquor. The correlations between the characteristics of the prepared porous materials and the dissolution properties of activated kaolinite were also investigated. The results show that the specific surface area (SSA of porous alumina/silica increases with silica/alumina dissolution, but without marked change of the BJH pore size. Furthermore, change in pore volume is more dependent on activation temperature. The porous alumina and silica obtained from alkali leaching of kaolinite activated at 1150 °C for 15 min and acid leaching of kaolinite activated at 850 °C for 15 min are mesoporous, with SSAs, BJH pore sizes and pore volumes of 55.8 m2/g and 280.3 m2/g, 6.06 nm and 3.06 nm, 0.1455 mL/g and 0.1945 mL/g, respectively. According to the adsorption tests, porous alumina has superior adsorption capacities for Cu2+, Pb2+ and Cd2+ compared with porous silica and activated carbon. The maximum capacities of porous alumina for Cu2+, Pb2+ and Cd2+ are 134 mg/g, 183 mg/g and 195 mg/g, respectively, at 30 °C.

Preparation and properties of antimony thin film anode materials

Institute of Scientific and Technical Information of China (English)

SU Shufa; CAO Gaoshao; ZHAO Xinbing

2004-01-01

Metallic antimony thin films were deposited by magnetron sputtering and electrodeposition. Electrochemical properties of the thin film as anode materials for lithium-ion batteries were investigated and compared with those of antimony powder. It was found that both magnetron sputtering and electrodeposition are easily controllable processes to deposit antimony films with fiat charge/discharge potential plateaus. The electrochemical performances of antimony thin films, especially those prepared with magnetron sputtering, are better than those of antimony powder. The reversible capacities of the magnetron sputtered antimony thin film are above 400 mA h g-1 in the first 15 cycles.

Mathematics for multimedia

CERN Document Server

Wickerhauser, Mladen Victor

2003-01-01

Mathematics and Multimedia focuses on the mathematics behind multimedia applications. This timely and thoroughly modern text is a rigorous survey of selected results from algebra and analysis, requiring only undergraduate math skills.The topics are `gems' chosen for their usefulness in understanding and creating application software for multimedia signal processing and communication.The book is aimed at a wide audience, including computer science and mathematics majors and those interested in employing mathematics in multimedia design and implementation. For the instructor, the material is divided into six chapters that may be presented in six lecture hours each. Thus, the entire text may be covered in one semester, with time left for examinations and student projects. For the student,there are more than 100 exercises with complete solutions, and numerous example programs in Standard C. Each chapter ends with suggestions for further reading. A companion website provides more insight for both instructors and s...

Pre-service teachers’ challenges in presenting mathematical problems

Science.gov (United States)

Desfitri, R.

2018-01-01

The purpose of this study was to analyzed how pre-service teachers prepare and assigned tasks or assignments in teaching practice situations. This study was also intended to discuss about kind of tasks or assignments they gave to students. Participants of this study were 15 selected pre-service mathematics teachers from mathematics education department who took part on microteaching class as part of teaching preparation program. Based on data obtained, it was occasionally found that there were hidden errors on questions or tasks assigned by pre-service teachers which might lead their students not to be able to reach a logical or correct answer. Although some answers might seem to be true, they were illogical or unfavourable. It is strongly recommended that pre-service teachers be more careful when posing mathematical problems so that students do not misunderstand the problems or the concepts, since both teachers and students were sometimes unaware of errors in problems being worked on.

Selective Preparation of trans-Carveol over Ceria Supported Mesoporous Materials MCM-41 and SBA-15

Directory of Open Access Journals (Sweden)

Nariman F. Salakhutdinov

2013-05-01

Full Text Available Ce-modified mesoporous silica materials MCM-41 and SBA-15, namely 32 wt % Ce–Si–MCM-41, 16 wt % Ce–H–MCM-41 and 20 wt % Ce–Si–SBA-15, were prepared, characterized and studied in the selective preparation of trans-carveol by α-pinene oxide isomerization. The characterizations of these catalysts were performed using scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption and FTIR pyridine adsorption. Selective preparation of trans-carveol was carried out in the liquid phase in a batch reactor. The activity and the selectivity of catalyst were observed to be influenced by their acidity, basicity and morphology of the mesoporous materials. The formation of trans-carveol is moreover strongly influenced by the basicity of the used solvent and in order to achieve high yields of this desired alcohol it is necessary to use polar basic solvent.

Porous chromatographic materials as substrates for preparing synthetic nuclear explosion debris particles

International Nuclear Information System (INIS)

Harvey, S.D.; Carman, A.J.; Martin Liezers; Antolick, K.C.; Garcia, B.J.; Eiden, G.C.; Sweet, L.E.

2013-01-01

Several porous chromatographic materials were investigated as synthetic substrates for preparing surrogate nuclear explosion debris particles. Eighteen metals, including some of forensic interest, were loaded onto materials by immersing them in metal solutions (556 mg/L of each metal) to fill the pores, applying gentle heat (110 deg C) to drive off water, and then treating them at high temperatures (up to 800 deg C) in air to form less soluble metal species. High-boiling-point metals were uniformly loaded on spherical controlled-pore glass to emulate early fallout, whereas low-boiling-point metals were loaded on core-shell silica to represent coated particles formed later in the nuclear fallout-formation process. Analytical studies characterized material balance and the formation of recalcitrant species. Metal loading was 1.5-3 times higher than expected from the pore volume alone, a result attributed to surface coating. Most metals were passively loaded; that is, solutions filled the pores without active metal discrimination. However, niobium and tin concentrations were lower in solutions after pore filling, and were found in elevated concentrations in the final products, indicating selective loading. High-temperature treatments caused reduced solubility of several metals, and the loss of some volatile species (rhenium and tellurium). Sample preparation reproducibility was high (the inter- and intra-batch relative standard deviations were 7.8 and 0.84 %, respectively) indicating suitability for use as a working standard for analytical methods development. We anticipate future standardized radionuclide-loaded materials will find use in radioanalytical methods development and/or serve as a starting material for the synthesis of more complex nuclear explosion debris forms (e.g., Trinitite). (author)

Guidelines for applying criteria to designate routes for transporting hazardous materials. Final report

International Nuclear Information System (INIS)

1989-07-01

These guidelines were prepared to assist State and local officials in the analysis of alternate routes to be used by highway vehicles transportating hazardous materials. A methodology for assessing comparative risks of routing alternatives is discussed and demonstrated through a hypothetical example. Mathematical models are provided for situations in which measured local data may not be easily obtained or adequate

Mathematics of aperiodic order

CERN Document Server

Lenz, Daniel; Savinien, Jean

2015-01-01

What is order that is not based on simple repetition, that is, periodicity? How must atoms be arranged in a material so that it diffracts like a quasicrystal? How can we describe aperiodically ordered systems mathematically? Originally triggered by the – later Nobel prize-winning – discovery of quasicrystals, the investigation of aperiodic order has since become a well-established and rapidly evolving field of mathematical research with close ties to a surprising variety of branches of mathematics and physics. This book offers an overview of the state of the art in the field of aperiodic order, presented in carefully selected authoritative surveys. It is intended for non-experts with a general background in mathematics, theoretical physics or computer science, and offers a highly accessible source of first-hand information for all those interested in this rich and exciting field. Topics covered include the mathematical theory of diffraction, the dynamical systems of tilings or Delone sets, their cohomolog...

Applied Wave Mathematics Selected Topics in Solids, Fluids, and Mathematical Methods

CERN Document Server

Quak, Ewald

2009-01-01

This edited volume addresses the importance of mathematics in wave-related research, and its tutorial style contributions provide educational material for courses or seminars. It presents highlights from research carried out at the Centre for Nonlinear Studies in Tallinn, Estonia, the Centre of Mathematics for Applications in Oslo, Norway, and by visitors from the EU project CENS-CMA. The example applications discussed include wave propagation in inhomogeneous solids, liquid crystals in mesoscopic physics, and long ship waves in shallow water bodies. Other contributions focus on specific mathe

An approach critical in mathematics education: Opportunities and interaction theory-practice-through critical mathematics education

Directory of Open Access Journals (Sweden)

Itamar Miranda da Silva

2011-06-01

Full Text Available This paper discusses the possibilities of articulation of theory-and-practice in the teaching, by means of critical mathematics education as a proposal for the teacher facing the challenges of daily life in the classroom. The discussion is based on the literature through which was estudied and analyzed several books, articles and dissertations on the subject, as well as our experiences and reflections resulting from the process of teacher education we experienced. From the readings and analysis was possible to construct a teaching proposal that suggests to address critical mathematics education as an alternative link between theory and practice and to assign to the teaching of mathematics a greater dynamism, with the prospect of developing knowledge and pedagogical practices that contribute to a broader training, which prepares for citizenship and for being critical students and teachers in the training process. Conjectures were raised about possible contributions of critical mathematics education as a differentiated alternative as opposed to reproductivist teaching. We believe therefore that this article could help with the reflections on the importance of mathematics education in teacher education which enables the realization that beyond disciplinary knowledge (content, are necessary pedagogical knowledge, curriculum and experiential to address the problems that relate to the teaching of mathematics

Problem Solving in the Digital Age: New Ideas for Secondary Mathematics Teacher Education

Science.gov (United States)

Abramovich, Sergei; Connell, Michael

2017-01-01

The paper reflects on an earlier research on the use of technology in secondary mathematics teacher education through the lenses of newer digital tools (Wolfram Alpha, Maple), most recent standards for teaching mathematics, and recommendations for the preparation of schoolteachers. New ideas of technology integration into mathematics education…

Mathematical epidemiology

CERN Document Server

Driessche, Pauline; Wu, Jianhong

2008-01-01

Based on lecture notes of two summer schools with a mixed audience from mathematical sciences, epidemiology and public health, this volume offers a comprehensive introduction to basic ideas and techniques in modeling infectious diseases, for the comparison of strategies to plan for an anticipated epidemic or pandemic, and to deal with a disease outbreak in real time. It covers detailed case studies for diseases including pandemic influenza, West Nile virus, and childhood diseases. Models for other diseases including Severe Acute Respiratory Syndrome, fox rabies, and sexually transmitted infections are included as applications. Its chapters are coherent and complementary independent units. In order to accustom students to look at the current literature and to experience different perspectives, no attempt has been made to achieve united writing style or unified notation. Notes on some mathematical background (calculus, matrix algebra, differential equations, and probability) have been prepared and may be downlo...

Preparation and characterization of macrocapsules containing microencapsulated PCMs (phase change materials) for thermal energy storage

International Nuclear Information System (INIS)

Han, Pengju; Lu, Lixin; Qiu, Xiaolin; Tang, Yali; Wang, Jun

2015-01-01

This paper was aimed to prepare, characterize and determine the comprehensive evaluation of promising composite macrocapsules containing microencapsulated PCMs (phase change materials) with calcium alginate gels as the matrix material. Macrocapsules containing microcapsules were fabricated by piercing-solidifying incuber method. Two kinds of microcapsules with n-tetradecane as core material, UF (urea-formaldehyde) and PMMA (poly(methyl methacrylate)) respectively as shell materials were prepared initially. For application concerns, thermal durability and mechanical property of macrocapsules were investigated by TGA (thermal gravimetric analysis) and Texture Analyser for the first time, respectively. The results showed excellent thermal stability and the compressive resistance of macrocapsules was sufficient for common application. The morphology and chemical structure of the prepared microcapsules and macrocapsules were characterized by SEM (scanning electron microscopy) and FT-IR (fourier transform infrared) spectroscopy method. Phase change behaviors and thermal durability of microcapsules and macrocapsules were investigated by DSC (differential scanning calorimetry). In order to improve latent heat of composite microcapsules, the core-shell weight ratio of tetradecane/UF shell microcapsules was chosen as 5.5:1 which obtained the phase change enthalpy of 194.1 J g −1 determined by DSC. In conclusion, these properties make it a feasible composite in applications of textile, building and cold-chain transportation. - Highlights: • We improved the phase change enthalpy with a higher core-shell ratio. • Urea-formaldehyde was firstly used as a shell material in the composite. • Mechanical and thermal durability property of the macrocapsules was firstly investigated in our work.

The Effect of Teacher Beliefs on Student Competence in Mathematical Modeling--An Intervention Study

Science.gov (United States)

Mischo, Christoph; Maaß, Katja

2013-01-01

This paper presents an intervention study whose aim was to promote teacher beliefs about mathematics and learning mathematics and student competences in mathematical modeling. In the intervention, teachers received written curriculum materials about mathematical modeling. The concept underlying the materials was based on constructivist ideas and…

Effect of preparation methods of LiNi1-xCoxO2 cathode materials on their chemical structure and electrode performance

International Nuclear Information System (INIS)

Cho, J.; Kim, G.; Lim, H.S.

1999-01-01

The authors have studied effects of different starting materials on preparation of LiNi 1-x Co x O 2 cathode material for a Li-ion cell where x = 0.1, 0.2, and 0.3, and the electrochemical properties of resulting compounds from two different preparation methods. A preparation method (method B) which uses spherical powder of Ni 1-x Co x (OH) 2 as one of the starting material produced a much superior cathode material than the other method (method A) which uses Ni(OH) 2 and Co(OH) 2 . Method A produced compounds with relatively high degrees of cation mixing which reduces electrochemical utilization (discharge capacity), increases irreversible capacity, and reduces stability on cycling of the cathode material. Method B, in contrast, produced cathode material with a much reduced degree of cation-mixing, thus improving the electrochemical properties. The spherical particle of material prepared by method B has the additional advantage of improved packing density of the electrode with improved volumetric energy density. The ratio of c/a was increased and the electrochemical stability on cycling of the material was improved as the content of Co (value of x) is increased

Prepare of microanalysis reference material for nuclear analysis of Chinese ancient ceramic

International Nuclear Information System (INIS)

Feng Songlin; Xu Qing; Feng Xiangqian; Fan Dongyu; Lei Yong; Cheng Lin

2005-01-01

Some analytic technique can play important role for identifying the provenance and age of ceramic ware. However, it is usually not allowed to destructive analyze for a valuable intact porcelain ware. These analysis methods such as X-ray Fluorescence (XRF), Proton Induced X-ray Emission (PIXE), and Synchrotron Radiation X-ray Fluorescence (SRXRF) are suitable for nondestructive analysis of ancient ceramic wares. In order to compare the analytic data obtained by different measuring method and identify the provenance and age accurately, the effective way is to calibrate elemental concentration in body and glaze of ceramic ware. Microanalysis reference material (MRM) of ancient ceramic has to be prepared for achieving quantitative analysis. A solid powder 99% in size of 500 mesh for microanalysis reference material (MRM) has being prepared in institute of high energy physics. The minimum analytic masses of 1 mg were determined by Neutron Activation Analysis (NAA) for these elements (Sc, Cr, Co, Rb: Cs, La, Ce, Nd, Sm, Tb, Yb, Lu; Hf, Ta, Th, U), and by SRXRF for elements (K, Ca, Ti, Mn, Fe, Zn; Rb, Sr).

Sample preparation techniques of biological material for isotope analysis

International Nuclear Information System (INIS)

Axmann, H.; Sebastianelli, A.; Arrillaga, J.L.

1990-01-01

Sample preparation is an essential step in all isotope-aided experiments but often it is not given enough attention. The methods of sample preparation are very important to obtain reliable and precise analytical data and for further interpretation of results. The size of a sample required for chemical analysis is usually very small (10mg-1500mg). On the other hand the amount of harvested plant material from plots in a field experiment is often bulky (several kilograms) and the entire sample is too large for processing. In addition, while approaching maturity many crops show not only differences in physical consistency but also a non-uniformity in 15 N content among plant parts, requiring a plant fractionation or separation into parts (vegetative and reproductive) e.g. shoots and spikes, in case of small grain cereals, shoots and pods in case of grain legumes and tops and roots or beets (including crown) in case of sugar beet, etc. In any case the ultimate goal of these procedures is to obtain representative subsample harvested from greenhouse or field experiments for chemical analysis. Before harvesting an isotopic-aided experiment the method of sampling has to be selected. It should be based on the type of information required in relation to the objectives of the research and the availability of resources (staff, sample preparation equipment, analytical facilities, chemicals and supplies, etc.). 10 refs, 3 figs, 3 tabs

Factoral analysis of the cost of preparing oil

Energy Technology Data Exchange (ETDEWEB)

Avdeyeva, L A; Kudoyarov, G Sh; Shmatova, M F

1979-01-01

Mathematical statistics methods (basically correlational and regression analysis) are used to study the factors which form the level of cost of preparing oil with consideration of the mutual influence of the factors. Selected as the claims for inclusion into a mathematical model was a group of five a priori justified factors: the water level of the oil being extracted (%); the specific expenditure of deemulsifiers; the volume of oil preparation; the quality of oil preparation (the salt content) and the level of use of the installations' capacities (%). To construct an economic and mathematical model of the cost of the technical preparation (SPP) of the oil, all the unions which make up the Ministry of the Oil Industry were divided into two comparable totalities. The first group included unions in which the oil SPP was lower than the branch average and the second, unions in which the SPP was higher than the branch wide cost. Using the coefficients of regression, special elasticity coefficients and the fluctuation indicators, the basic factors were finally identified which have the greatest influence on the formation of the oil SPP level separately for the first and second groups of unions.

Sampling and sample preparation methods for the analysis of trace elements in biological material

International Nuclear Information System (INIS)

Sansoni, B.; Iyengar, V.

1978-05-01

The authors attempt to give a most systamtic possible treatment of the sample taking and sample preparation of biological material (particularly in human medicine) for trace analysis (e.g. neutron activation analysis, atomic absorption spectrometry). Contamination and loss problems are discussed as well as the manifold problems of the different consistency of solid and liquid biological materials, as well as the stabilization of the sample material. The process of dry and wet ashing is particularly dealt with, where new methods are also described. (RB) [de

Preparation of Reduced Graphene Oxides as Electrode Materials for Supercapacitors

KAUST Repository

Bai, Yaocai

2012-06-01

Reduced graphene oxide as outstanding candidate electrode material for supercapacitor has been investigated. This thesis includes two topics. One is that three kinds of reduced graphene oxides were prepared by hydrothermal reduction under different pH conditions. The pH values were found to have great influence on the reduction of graphene oxides. Acidic and neutral media yielded reduced graphene oxides with more oxygen-functional groups, lower specific surface areas but broader pore size distributions than those in basic medium. Variations induced by the pH changes resulted in great differences in the supercapacitor performance. The graphene produced in the basic solution presented mainly electric double layer behavior with specific capacitance of 185 F/g, while the other two showed additional pseudocapacitance behavior with specific capacitance of 225 F/g (acidic) and 230 F/g (neutral), all at a constant current density of 1A/g. The other one is that different reduced graphene oxides were prepared via solution based hydrazine reduction, low temperature thermal reduction, and hydrothermal reduction. The as- prepared samples were then investigated by UV-vis spectroscopy, X-ray diffraction, Raman spectroscopy, and Scanning electron microscope. The supercapacitor performances were also studied and the hydrothermally reduced graphene oxide exhibited the highest specific capacitance.

Think Pair Share Using Realistic Mathematics Education Approach in Geometry Learning

Science.gov (United States)

Afthina, H.; Mardiyana; Pramudya, I.

2017-09-01

This research aims to determine the impact of mathematics learning applying Think Pair Share (TPS) using Realistic Mathematics Education (RME) viewed from mathematical-logical intelligence in geometry learning. Method that used in this research is quasi experimental research The result of this research shows that (1) mathematics achievement applying TPS using RME approach gives a better result than those applying direct learning model; (2) students with high mathematical-logical intelligence can reach a better mathematics achievement than those with average and low one, whereas students with average mathematical-logical intelligence can reach a better achievement than those with low one; (3) there is no interaction between learning model and the level of students’ mathematical-logical intelligence in giving a mathematics achievement. The impact of this research is that TPS model using RME approach can be applied in mathematics learning so that students can learn more actively and understand the material more, and mathematics learning become more meaningful. On the other hand, internal factors of students must become a consideration toward the success of students’ mathematical achievement particularly in geometry material.

Preparation of standard hair material and development of analytical methodology

International Nuclear Information System (INIS)

Gangadharan, S.; Walvekar, A.P.; Ali, M.M.; Thantry, S.S.; Verma, R.; Devi, R.

1995-01-01

The concept of the use of human scalp hair as a first level indicator of exposure to inorganic pollutants has been established by us earlier. Efforts towards the preparation of a hair reference material are described. The analytical approaches for the determination of total mercury by cold vapour AAS and INAA and of methylmercury by extraction combined with gas chromatography coupled to an ECD are summarized with results on some of the samples analyzed, including the stability of values over a period of time of storage. (author)

Difference, inclusion, and mathematics education

DEFF Research Database (Denmark)

Figueiras, Lourdes; Healy, Lulu; Skovsmose, Ole

2016-01-01

The round-table discussion on Difference, Inclusion and Mathematics Education was in included in the scientific programme of VI SIPEM in recognition and celebration of the emerging body of research into the challenges of building a culture of mathematics education which values and respects...... the diversity of learners in different educational contexts – in Brazil and beyond. This paper presents the contributions to the discussion, which focus on the problematisation of the term “inclusion”, explorations of how the practices of previously marginalized students can bring new resources to the teaching...... and learning of mathematics and reflections upon the potentially discriminatory nature of the structures which currently mould school mathematics. The paper aims to serve as material for the developing research agenda of the thirteenth working group of the Brazilian Society of Mathematics Education, which met...

Hypothetical learning trajectory design on the history of Indonesian independence struggle in Mathematics logic instruction

Directory of Open Access Journals (Sweden)

Dra Nurjanah

2017-12-01

Full Text Available The research was aimed at developing learning resources for mathematics logic using the hypothetical learning trajectory designed through reflection on the history of Indonesian independence struggle. The study was carried out at the Department of Mathematics Education of the Faculty of Teacher Training and Educational Sciences Nusantara Islamic University (Uninus. The study used design research consisted of three stages: preparing the experiments, design the experiments, and retrospective analysis. Preparing the experiments stage has been completed and design the experiments stage is currently under preparation. The main activities accomplished in preparing the experiments stage consisted of: studies of Indonesian independence struggle, curriculum analysis, literature review, and early prototype design. Design the experiments phase has enabled the development of the research instruments. The learning trajectory which has been designed in the first stage involved: reflections on the history of Indonesian independence struggle; implication and bi-implication; implication, bi-implication and their truth in the context of the history of the Indonesian independence struggle; and implication, bi-implication and their truth in the context of mathematics. Based on the results of discussions with colleagues, the students’ ability in mathematical thinking can be developed by using the history of Indonesian independence struggle as the context of learning in a mathematics logics course.

To the analysis of the theory of mathematical model of hydrodynamics of a bulk layer of a mix of vegetative materials

Directory of Open Access Journals (Sweden)

S. A. Bikov

2012-01-01

Full Text Available The article presents the results of research work on finding out the interdependence between the dynamic separation of the working apparatus (machine, statistic separation and the degree of filling the apparatus (machine. The final mathematic model of calculating separation - an important hydrodynamic parameter of a layer of vegetable material while extragent is being filtrated through it. The authors worked out a universal method of defining hydrodynamic characteristics of a layer of material which can be applied to any vegetable materials and their mixtures worked up as required.

Preparation of a Sulfonated Carbonaceous Material from Lignosulfonate and Its Usefulness as an Esterification Catalyst

Directory of Open Access Journals (Sweden)

Duckhee Lee

2013-07-01

Full Text Available Sulfonated carbonaceous material useful as a solid acid catalyst was prepared from lignosulfonate, a waste of the paper-making industry sulfite pulping process, and characterized by 13C-NMR, FT-IR, TGA, SEM and elemental analysis, etc. The sulfonic acid group density and total density of all acid groups in the sulfonated carbonaceous material was determined by titration to be 1.24 mmol/g and 5.90 mmol/g, respectively. Its catalytic activity in the esterification of cyclohexanecarboxylic acid with anhydrous ethanol was shown to be comparable to that of the ionic exchange resin Amberlyst-15, when they were used in the same amount. In the meantime, the sulfonic acid group was found to be leached out by 26%–29% after it was exposed to hot water (95 °C for 5 h. The catalytic usefulness of the prepared carbonaceous material was investigated by performing esterifications.

Nanocasting of Periodic Mesoporous Materials as an Effective Strategy to Prepare Mixed Phases of Titania

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Luther Mahoney

2015-12-01

Full Text Available Mesoporous titanium dioxide materials were prepared using a nanocasting technique involving silica SBA-15 as the hard-template. At an optimal loading of titanium precursor, the hexagonal periodic array of pores in SBA-15 was retained. The phases of titanium dioxide could be easily varied by the number of impregnation cycles and the nature of titanium alkoxide employed. Low number of impregnation cycles produced mixed phases of anatase and TiO2(B. The mesoporous TiO2 materials were tested for solar hydrogen production, and the material consisting of 98% anatase and 2% TiO2(B exhibited the highest yield of hydrogen from the photocatalytic splitting of water. The periodicity of the pores was an important factor that influenced the photocatalytic activity. This study indicates that mixed phases of titania containing ordered array of pores can be prepared by using the nanocasting strategy.

Provisional Approaches to Goals for School Mathematics; Cambridge Conference on School Mathematics Feasibility Study No. 37.

Science.gov (United States)

Cambridge Conference on School Mathematics, Newton, MA.

These materials were written with the aim of reflecting the thinking of Cambridge Conference on School Mathematics (CCSM) regarding the goals and objectives for school mathematics K-6. In view of the experiences of other curriculum groups and of the general discussions since 1963, the present report initiates the next step in evolving the "Goals".…

Preparation, characterization and certification of uranium isotope reference materials

International Nuclear Information System (INIS)

Oliveira Junior, Olivio Pereira de

2006-01-01

This work describes the preparation, characterization and certification of a set of uranium isotope reference materials ranging from 0.5 to 20.0 % of 235 U in mass. The most important concepts of metrology in chemical measurements were applied so that the certified quantities in these materials could be directly traceable to the International System of Units (SI). As a consequence of this approach, these materials can be used in the instruments calibration, estimation of measurement uncertainty, method validation, assessment of performance of analysts, quality control routines and interlaboratory comparison programmes. The most advanced methods and techniques in mass spectrometry, that is, gas source mass spectrometry (GSMS), thermal ionisation mass spectrometry (TIMS) and inductively coupled plasma mass spectrometry (ICPMS) were investigated to identify which are the dominant components in the uncertainty and to quantify its contribution to the final value of the measurement uncertainty of the isotopic ratio. The results obtained were then compared to verify which are the methods and techniques associated to the lowest measurement uncertainty values. The isotope amount ratio n( 235 U)/n( 238 U) was certified in the materials produced to expanded uncertainties ranging from 0.02 to 0.10 % and the ratios n( 234 U)/n( 238 U) and n( 236 U)/n( 238 U), to uncertainties ranging from 0.03 to 2.20 %. These values fully comply to the requirements of the isotopic characterization of nuclear fuel as well as the analysis of environmental samples for nuclear safeguards. (author)

Preparation and thermal properties characterization of carbonate salt/carbon nanomaterial composite phase change material

International Nuclear Information System (INIS)

Tao, Y.B.; Lin, C.H.; He, Y.L.

2015-01-01

Highlights: • Nanocomposite phase change materials were prepared and characterized. • Larger specific surface area is more efficient to enhance specific heat. • Columnar structure is more efficient to enhance thermal conductivity. • Thermal conductivity enhancement is the key. • Single walled carbon nanotube is the optimal nanomaterial additive. - Abstract: To enhance the performance of high temperature salt phase change material, four kinds of carbon nanomaterials with different microstructures were mixed into binary carbonate eutectic salts to prepare carbonate salt/nanomaterial composite phase change material. The microstructures of the nanomaterial and composite phase change material were characterized by scanning electron microscope. The thermal properties such as melting point, melting enthalpy, specific heat, thermal conductivity and total thermal energy storage capacity were characterized. The results show that the nanomaterial microstructure has great effects on composite phase change material thermal properties. The sheet structure Graphene is the best additive to enhance specific heat, which could be enhanced up to 18.57%. The single walled carbon nanotube with columnar structure is the best additive to enhance thermal conductivity, which could be enhanced up to 56.98%. Melting point increases but melting enthalpy decreases with nanomaterial specific surface area increase. Although the additives decrease the melting enthalpy of composite phase change material, they also enhance the specific heat. As a combined result, the additives have little effects on thermal energy storage capacity. So, for phase change material performance enhancement, more emphasis should be placed on thermal conductivity enhancement and single walled carbon nanotube is the optimal nanomaterial additive

Improvements in or relating to method of preparing porous material/synthetic polymer composites

International Nuclear Information System (INIS)

Hills, P.R.; McGahan, D.J.

1976-01-01

A method for preparing a composite material is described comprising polymerising a monoethylenically unsaturated monomer of a mixture of copolymerisable monoethylenically unsaturated monomers in a porous material, excluding a porous natural cellulosic fibre material, the polymerisable liquid being admixed in the porous material with a saturated aliphatic hydrocarbon or a halogen derivative thereof. It is preferable that the polymerisable liquid and the hydrocarbon or halogen derivative are present in the porous material. Impregnation may be carried out by a vacuum technique or by simple immersion. The monomers that may be used are listed, but a mixture of styrene and acrylonitrile is preferred in the proportions 60 : 40 by volume. Polymerisation may be effected by irradiation, preferably with 60 Co γ-radiation. Suitable porous materials include concrete, stone, and fibreboard. If concrete is used the composite material may be used for pressure pipes and other articles normally made of steel. Examples of the application of the process are given. (U.K.)

Secondary School Mathematics Teachers’ and Students’ Views on Computer Assisted Mathematics Instruction in Turkey: Mathematica Example

Directory of Open Access Journals (Sweden)

Mehmet Alper Ardıç

2017-01-01

Full Text Available This study aimed at determining the secondary school mathematics teachers’ and students’ views on computer-assisted mathematics instruction (CAMI conducted via Mathematica. Accordingly, three mathematics teachers in Adıyaman and nine 10th-grade students participated in the research. Firstly, the researchers trained the mathematics teachers in the Mathematica program, a computer algebra system (CAS and CAMI. Then, they provided a suitable environment for teachers to practice CAMI with their students to teach quadratic functions (parabola. Case study, a qualitative research design, was utilized in the study. Semi-structured interview forms were used as data collection tools. The interview data were analyzed using descriptive and content analysis, and the codes and themes related to the topic were obtained. The findings revealed that all the teachers found CAMI implementations interesting as supported by students’ views. While all mathematics teachers wanted to benefit from CAMI in mathematics and geometry courses, most of the students asked that CAMI be used in different courses. It was found that students did not have any problems with the Mathematica used with CAMI activities. However, it was also revealed by one student and one teacher that involving CAMI constantly in the courses would hinder preparations for the university entrance exam.

G.W. Leibniz, interrelations between mathematics and philosophy

CERN Document Server

Goethe, Norma B; Rabouin, David

2015-01-01

Up to now there have been scarcely any publications on Leibniz dedicated to investigating the interrelations between philosophy and mathematics in his thought. In part this is due to the previously restricted textual basis of editions such as those produced by Gerhardt. Through recent volumes of the scientific letters and mathematical papers series of the Academy Edition scholars have obtained a much richer textual basis on which to conduct their studies - material which allows readers to see interconnections between his philosophical and mathematical ideas which have not previously been manifested. The present book draws extensively from this recently published material. The contributors are among the best in their fields. Their commissioned papers cover thematically salient aspects of the various ways in which philosophy and mathematics informed each other in Leibniz's thought.

Handbook of mathematical methods in imaging

CERN Document Server

2015-01-01

The Handbook of Mathematical Methods in Imaging provides a comprehensive treatment of the mathematical techniques used in imaging science. The material is grouped into two central themes, namely, Inverse Problems (Algorithmic Reconstruction) and Signal and Image Processing. Each section within the themes covers applications (modeling), mathematics, numerical methods (using a case example) and open questions. Written by experts in the area, the presentation is mathematically rigorous. This expanded and revised second edition contains updates to existing chapters and 16 additional entries on important mathematical methods such as graph cuts, morphology, discrete geometry, PDEs, conformal methods, to name a few. The entries are cross-referenced for easy navigation through connected topics. Available in both print and electronic forms, the handbook is enhanced by more than 200 illustrations and an extended bibliography. It will benefit students, scientists and researchers in applied mathematics. Engineers and com...

Preparation and Characterization of Carbon Nano tube-based Electrochromic Material

International Nuclear Information System (INIS)

Muhammad Shahazmi Mohd Zambri; Norani Muti Mohamed; Kait, C.F.

2011-01-01

Electrochromic materials that can change their optical properties reversibly for an applied potential due to electrochemical oxidation and reduction have been used in various applications of electrochromic windows or smart glass. Conducting polymer like poly aniline (PANI) is one of the most promising electrochromic materials because of its ease of synthesis and environmental stability. However, the electrochemically deposited poly aniline exhibit substantial resistivity which is attributed to the lack of conducting pathways at the nano scale associated with random deposition morphology. This paper describes the study in developing electrochromic material that will exhibit higher conductivity by using carbon nano tubes (CNTs) as the filler. Preparation of electrochromic material on ITO and FTO glass substrate was done by electrochemical process using mixture of CNTs and PANI in H 2 SO 4 at several loading of CNTs, voltage applied and duration of the process. PANI and PANI/ CNTs films produced were then characterized using SEM and Hall Effect measurement. From the study, highly conductive PANI/ CNTs film can be obtained by using optimum condition of the process parameters. PANI film deposited on FTO glass substrate was also found to be of good quality with conductivity two orders of magnitude higher than the film deposited on ITO glass substrate. (author)

Business Mathematics for Business Education Departments in Pennsylvania's Public Schools.

Science.gov (United States)

Parfet, James A.

This document is meant to be used as a teaching aid to help business teachers in Pennsylvania high schools prepare pupils to assume positions in business offices. Methods are suggested by which business mathematics may be presented to develop the greatest level of pupil achievement. The chapters outline business mathematics in the high school…

Method of preparation of carbon materials for use as electrodes in rechargeable batteries

Science.gov (United States)

Doddapaneni, Narayan; Wang, James C. F.; Crocker, Robert W.; Ingersoll, David; Firsich, David W.

1999-01-01

A method of producing carbon materials for use as electrodes in rechargeable batteries. Electrodes prepared from these carbon materials exhibit intercalation efficiencies of .apprxeq.80% for lithium, low irreversible loss of lithium, long cycle life, are capable of sustaining a high rates of discharge and are cheap and easy to manufacture. The method comprises a novel two-step stabilization process in which polymeric precursor materials are stabilized by first heating in an inert atmosphere and subsequently heating in air. During the stabilization process, the polymeric precursor material can be agitated to reduce particle fusion and promote mass transfer of oxygen and water vapor. The stabilized, polymeric precursor materials can then be converted to a synthetic carbon, suitable for fabricating electrodes for use in rechargeable batteries, by heating to a high temperature in a flowing inert atmosphere.

Boundary crossing and brokering between disciplines in pre-service mathematics teacher education

Science.gov (United States)

Goos, Merrilyn; Bennison, Anne

2017-12-01

In many countries, pre-service teacher education programs are structured so that mathematics content is taught in the university's mathematics department and mathematics pedagogy in the education department. Such program structures make it difficult to authentically interweave content with pedagogy in ways that acknowledge the roles of both mathematicians and mathematics educators in preparing future teachers. This article reports on a project that deliberately fostered collaboration between mathematicians and mathematics educators in six Australian universities in order to investigate the potential for learning at the boundaries between the two disciplinary communities. Data sources included two rounds of interviews with mathematicians and mathematics educators and annual reports prepared by each participating university over the three years of the project. The study identified interdisciplinary boundary practices that led to integration of content and pedagogy through new courses co-developed and co-taught by mathematicians and mathematics educators, and new approaches to building communities of pre-service teachers. It also developed an evidence-based classification of conditions that enable or hinder sustained collaboration across disciplinary boundaries, together with an empirical grounding for Akkerman and Bakker's conceptualisation of transformation as a mechanism for learning at the boundary between communities. The study additionally highlighted the ambiguous nature of boundaries and implications for brokers who work there to connect disciplinary paradigms.

Task Modification and Knowledge Utilization by Korean Prospective Mathematics Teachers

Science.gov (United States)

Lee, Kyeong-Hwa; Lee, Eun-Jung; Park, Min-Sun

2016-01-01

It has been asserted that mathematical tasks play a critical role in the teaching and learning of mathematics. Modification of tasks included in intended curriculum materials, such as textbooks, can be an effective activity for prospective teachers to understand the role of mathematical tasks in the teaching and learning of mathematics; designing…

How Preservice Teachers Use Children’s Literature to Teach Mathematical Concepts: Focus on Mathematical Knowledge for Teaching

Directory of Open Access Journals (Sweden)

Jennifer EDELMAN

2017-06-01

Full Text Available This descriptive study examines the elements of mathematical knowledge for teaching (MKT that elementary teacher candidates exhibit as they plan, teach, and reflect on a mathematics lesson that integrates children’s literature. Data for this study were gathered from observations and written work of preservice elementary teacher candidates enrolled in a methods of teaching mathematics course. The data were analyzed using three criteria: that of knowledge of content and students, knowledge of content and teaching, and knowledge of content and curriculum. The findings suggest a need for further development of teacher candidates’ ability to identify and locate mathematical concepts in children’s literature, as well as the need for supporting teacher candidates’ critical analysis of curricular materials and mathematical representations in children’s literature.

How preservice teachers use children’s literature to teach mathematical concepts: Focus on mathematical knowledge for teaching

Directory of Open Access Journals (Sweden)

Jennifer Edelman

2017-06-01

Full Text Available This descriptive study examines the elements of mathematical knowledge for teaching (MKT that elementary teacher candidates exhibit as they plan, teach, and reflect on a mathematics lesson that integrates children’s literature. Data for this study were gathered from observations and written work of preservice elementary teacher candidates enrolled in a methods of teaching mathematics course. The data were analyzed using three criteria: that of knowledge of content and students, knowledge of content and teaching, and knowledge of content and curriculum. The findings suggest a need for further development of teacher candidates’ ability to identify and locate mathematical concepts in children’s literature, as well as the need for supporting teacher candidates’ critical analysis of curricular materials and mathematical representations in children’s literature.

A mathematical approach to research problems of science and technology theoretical basis and developments in mathematical modeling

CERN Document Server

Ei, Shin-ichiro; Koiso, Miyuki; Ochiai, Hiroyuki; Okada, Kanzo; Saito, Shingo; Shirai, Tomoyuki

2014-01-01

This book deals with one of the most novel advances in mathematical modeling for applied scientific technology, including computer graphics, public-key encryption, data visualization, statistical data analysis, symbolic calculation, encryption, error correcting codes, and risk management. It also shows that mathematics can be used to solve problems from nature, e.g., slime mold algorithms. One of the unique features of this book is that it shows readers how to use pure and applied mathematics, especially those mathematical theory/techniques developed in the twentieth century, and developing now, to solve applied problems in several fields of industry. Each chapter includes clues on how to use "mathematics" to solve concrete problems faced in industry as well as practical applications. The target audience is not limited to researchers working in applied mathematics and includes those in engineering, material sciences, economics, and life sciences.

Teachers mathematical communication profile in explaining subject matter

Science.gov (United States)

Umami, Rohmatul; Budayasa, I. Ketut; Suwarsono, St.

2017-12-01

This study aimed to see a teachers mathematical communication profile in explaining a subject matter. It is a qualitative research. A high-school junior teacher (i.e., a teacher with 1- to 5-year experience) teaching mathematics at X-Social Class was selected as the subject of this study. The data was collected by observing the teachers mathematical communication in explaining a given material (i.e., the rule of sine) in class and an in-depth interview would be organized respectively. The result showed that the junior teacher explained the subject matter in systematic, complete, fluent, and centered manner. In this case, she began with reminding students on the previous material related to the current material to be learned, informing the current learning objectives, and finally delivering the subject matter. To support her explanation, the teacher also provided some related information, led the students attention into the given material by asking them particular related questions, and did not use any confusing terms. However, the study found that some of high-school teachers still used less appropriate language in explaining materials.

Preparation of a porous Sn@C nanocomposite as a high-performance anode material for lithium-ion batteries

Science.gov (United States)

Zhang, Yanjun; Jiang, Li; Wang, Chunru

2015-07-01

A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries.A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries. Electronic supplementary information (ESI) available: Detailed experimental procedure and additional characterization, including a Raman spectrum, TGA curve, N2 adsorption-desorption isotherm, TEM images and SEM images. See DOI: 10.1039/c5nr03093e

Preparation and Characterization of Biomass-Derived Advanced Carbon Materials for Lithium-Ion Battery Applications

Science.gov (United States)

Hardiansyah, Andri; Chaldun, Elsy Rahimi; Nuryadin, Bebeh Wahid; Fikriyyah, Anti Khoerul; Subhan, Achmad; Ghozali, Muhammad; Purwasasmita, Bambang Sunendar

2018-07-01

In this study, carbon-based advanced materials for lithium-ion battery applications were prepared by using soybean waste-based biomass material, through a straightforward process of heat treatment followed by chemical modification processes. Various types of carbon-based advanced materials were developed. Physicochemical characteristics and electrochemical performance of the resultant materials were characterized systematically. Scanning electron microscopy observation revealed that the activated carbon and graphene exhibits wrinkles structures and porous morphology. Electrochemical impedance spectroscopy (EIS) revealed that both activated carbon and graphene-based material exhibited a good conductivity. For instance, the graphene-based material exhibited equivalent series resistance value of 25.9 Ω as measured by EIS. The graphene-based material also exhibited good reversibility and cyclic performance. Eventually, it would be anticipated that the utilization of soybean waste-based biomass material, which is conforming to the principles of green materials, could revolutionize the development of advanced material for high-performance energy storage applications, especially for lithium-ion batteries application.

Preparation of sintered foam materials by alkali-activated coal fly ash.

Science.gov (United States)

Zhao, Yelong; Ye, Junwei; Lu, Xiaobin; Liu, Mangang; Lin, Yuan; Gong, Weitao; Ning, Guiling

2010-02-15

Coal fly ash from coal fired power stations is a potential raw material for the production of ceramic tiles, bricks and blocks. Previous works have demonstrated that coal fly ash consists mainly of glassy spheres that are relatively resistant to reaction. An objective of this research was to investigate the effect of alkali on the preparation process of the foam material. Moreover, the influence of foam dosage on the water absorption, apparent density and compressive strength was evaluated. The experimental results showed that homogenous microstructures of interconnected pores could be obtained by adding 13 wt.% foaming agent at 1050 degrees C, leading to foams presenting water absorption, apparent density and compressive strength values of about 126.5%, 0.414 g/cm(3), 6.76 MPa, respectively.

The preparation and analysis of minerals for use as reference material

International Nuclear Information System (INIS)

Stoch, H.

1976-01-01

This report covers the progress made in the collection of the material for reference samples, and the five interlaboratory analytical programmes (ferrochromium slags, fluorspar, 'mixed' NIMROC samples, rare earths, and ferromanganese slags). The description of the internal analytical programme has been subdivided into eight main categories, and a comprehensive list of evaluated results covering a wide range of materials is included. Additional results for thorium, rare earths, tin, tantalum, and niobium for the appropriate reference samples are included in updated tables. The main purpose in the preparation of these samples is to provide control samples for analytical work at the National Institute for Metallurgy. Where there is a special need, limited quantities of the samples can be made available to other laboratories

Y2O3-W Continuous Graded Materials by Co-sedimentation

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WANG Shi-yang

2017-09-01

Full Text Available The raw Y2O3 powder was classified and graded based on modified co-sedimentation mathematical model,using the size distribution of W particles as the known condition. Y2O3-W continuous graded materials with the composition distribution index P values of 1.0, 0.7, 0.3 and 0.1 were prepared by co-sedimentation and hot-pressing. The results show that the Y2O3 powder consistent with the design requirements can be obtained by graduation method. The gradient continuity of materials can be verified by microstructure observation and hardness testing.

Preparation and characterization of 304 stainless steel/Q235 carbon steel composite material

Science.gov (United States)

Shen, Wenning; Feng, Lajun; Feng, Hui; Cao, Ying; Liu, Lei; Cao, Mo; Ge, Yanfeng

The composite material of 304 stainless steel reinforced Q235 carbon steel has been prepared by modified hot-rolling process. The resulted material was characterized by scanning electron microscope, three-electrode method, fault current impact method, electrochemical potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy. The results showed that metallurgical bond between the stainless steel layer and carbon steel substrate has been formed. The composite material exhibited good electrical conductivity and thermal stability. The average grounding resistance of the composite material was about 13/20 of dip galvanized steel. There has no surface crack and bubbling formed after fault current impact. The composite material led to a significant decrease in the corrosion current density in soil solution, compared with that of hot dip galvanized steel and bare carbon steel. On the basis polarization curve and EIS analyses, it can be concluded that the composite material showed improved anti-corrosion property than hot-dip galvanized steel.

Nitrogen-doped hierarchical porous carbon materials prepared from meta-aminophenol formaldehyde resin for supercapacitor with high rate performance

International Nuclear Information System (INIS)

Zhou, Jin; Zhang, Zhongshen; Xing, Wei; Yu, Jing; Han, Guoxing; Si, Weijiang; Zhuo, Shuping

2015-01-01

Graphical abstract: N-doped hierarchical porous carbons with high rate capacitive performance are prepared by a combination method of nano-SiO 2 template/KOH activation. - Highlights: • A mass produced nano-SiO 2 is used to prepared hierarchical porous carbon. • N-doped hierarchical porous carbon materials are easily prepared. • The NHPCs materials exhibit a very high capacitance of up to 260.5 F g −1 . • The NHPC-800 sample shows very high rate capability. • Hierarchical porosity and N-doping synergistically enhances the whole capacitance. - Abstract: In this work, nitrogen-doped hierarchical porous carbon materials (NHPCs) are prepared by a two-step method combined of a hard template process and KOH-activation treatment. Low cost and large-scale commercial nano-SiO 2 are used as a hard template. The hierarchical porosity, structure and nitrogen-doped surface chemical properties are proved by a varies of means, such as scanning electron microscopy, transition electron microscopy, N 2 sorption, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. When the prepared NHPCs materials are used as the electrode materials for supercapacitors in KOH electrolyte, they exhibit very high specific capacitance, good power capability and excellent cyclic stability. NHPC-800 carbon shows a high capacitance of 114.0 F g −1 at the current density of 40 A g −1 , responding to a high energy and power densities of 4.0 Wh kg −1 and 10 000 W kg −1 , and a very short drain time of 1.4 s. The excellent capacitive performance may be due to the synergistic effect of the hierarchical porosity, high effective surface area and heteroatom doping, resulting in both electrochemical double layer and Faradaic capacitance contributions

Mathematical and computational analyses of cracking formation fracture morphology and its evolution in engineering materials and structures

CERN Document Server

Sumi, Yoichi

2014-01-01

This book is about the pattern formation and the evolution of crack propagation in engineering materials and structures, bridging mathematical analyses of cracks based on singular integral equations, to computational simulation of engineering design. The first two parts of this book focus on elasticity and fracture and provide the basis for discussions on fracture morphology and its numerical simulation, which may lead to a simulation-based fracture control in engineering structures. Several design concepts are discussed for the prevention of fatigue and fracture in engineering structures, including safe-life design, fail-safe design, damage tolerant design. After starting with basic elasticity and fracture theories in parts one and two, this book focuses on the fracture morphology that develops due to the propagation of brittle cracks or fatigue cracks.   In part three, the mathematical analysis of a curved crack is precisely described, based on the perturbation method. The stability theory of interactive ...

Preparation and utilization of metal oxide fine powder

Energy Technology Data Exchange (ETDEWEB)

Kim, Joon Soo; Jang, Hee Dong; Lim, Young Woong; Kim, Sung Don; Lee, Hi Sun; Lee, Hoo In; Kim, Chul Joo; Shim, Gun Joo; Jang, Dae Kyu [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-01

Metal oxide fine powders finds many applications in industry as new materials. It is very much necessary for the development of such powders to improve the domestic industry. The purpose of present research is to develop a process for the preparation and utilization of metal oxide fine powder. This project is consisted of two main subjects. (1) Production of ultrafine metal oxide powder: Ultrafine metal oxide powder is defined as a metal oxide powder of less than 100 nanometer in particle size. Experiments for the control of particle size and distributions in the various reaction system and compared with results of (2 nd year research). Various reaction systems were adopted for the development of feasible process. Ultrafine particles could be prepared even higher concentration of TiCl{sub 4} and lower gas flowrate compared to TiCl{sub 4}-O{sub 2} system in the TiCl{sub 4}-Air-H{sub 2}O system. Ultrafine Al{sub 2}O{sub 3} powders also prepared with the change of concentration and gas flowrate. Experiments on the treatment of surface characteristics of ultrafine TiO{sub 2} powders were investigated using esterification and surface treating agents. A mathematical model that can predict the particle size and distribution was also developed. (2) Preparation of cerium oxide for high-grade polishing powder: Used cerium polishing powder was recycled for preparation of high grade cerium oxide polishing powder. Also, cerium hydroxide which was generated as by-product in processing of monazite ore was used as another material. These two materials were leached respectively by using acid, and the precipitate was gained in each leached solution by adjusting pH of the solution, and by selective crystallization. These precipitates were calcined to make high grade cerium oxide polishing powder. The effect of several experimental variables were investigated, and the optimum conditions were obtained through the experiments. (author). 81 refs., 49 figs., 27 tabs.

Mathematical modelling of the growth of human fetus anatomical structures.

Science.gov (United States)

Dudek, Krzysztof; Kędzia, Wojciech; Kędzia, Emilia; Kędzia, Alicja; Derkowski, Wojciech

2017-09-01

The goal of this study was to present a procedure that would enable mathematical analysis of the increase of linear sizes of human anatomical structures, estimate mathematical model parameters and evaluate their adequacy. Section material consisted of 67 foetuses-rectus abdominis muscle and 75 foetuses- biceps femoris muscle. The following methods were incorporated to the study: preparation and anthropologic methods, image digital acquisition, Image J computer system measurements and statistical analysis method. We used an anthropologic method based on age determination with the use of crown-rump length-CRL (V-TUB) by Scammon and Calkins. The choice of mathematical function should be based on a real course of the curve presenting growth of anatomical structure linear size Ύ in subsequent weeks t of pregnancy. Size changes can be described with a segmental-linear model or one-function model with accuracy adequate enough for clinical purposes. The interdependence of size-age is described with many functions. However, the following functions are most often considered: linear, polynomial, spline, logarithmic, power, exponential, power-exponential, log-logistic I and II, Gompertz's I and II and von Bertalanffy's function. With the use of the procedures described above, mathematical models parameters were assessed for V-PL (the total length of body) and CRL body length increases, rectus abdominis total length h, its segments hI, hII, hIII, hIV, as well as biceps femoris length and width of long head (LHL and LHW) and of short head (SHL and SHW). The best adjustments to measurement results were observed in the exponential and Gompertz's models.

Evaluation of Mathematical Game Design Skills of Pre-Service Classroom Teachers

Science.gov (United States)

Pilten, Pusat; Pilten, Gülhiz; Divrik, Ramazan; Divrik, Fatma

2017-01-01

The purpose of the research is to evaluate the games prepared by pre-service classroom teachers within the scope of "Mathematics Teaching 1" and "Mathematics Teaching 2" courses, which are included in the undergraduate classroom teaching programs in Turkey, and to make predictions on the game design skills of pre-service…

Preparation process and properties of LiCoO{sub 2}/PANI/dodecylbenzenesulfonate composite electrode materials

Energy Technology Data Exchange (ETDEWEB)

Ferchichi, Karima, E-mail: ferchichikarima1@gmail.com [UR Physico-Chimie des Matériaux Solides, Faculté des Sciences de Tunis, Manar II, 2092 Tunis (Tunisia); Hbaieb, Souhaira, E-mail: souhaira.bouchaira@gmail.com [UR Physico-Chimie des Matériaux Solides, Faculté des Sciences de Tunis, Manar II, 2092 Tunis (Tunisia); Amdouni, Noureddine, E-mail: nouredin.amdouni@fst.rnu.tn [UR Physico-Chimie des Matériaux Solides, Faculté des Sciences de Tunis, Manar II, 2092 Tunis (Tunisia); Kalfat, Rafik, E-mail: rafik.kalfat@gmail.com [Institut National de Recherche et d' Analyse Physico-Chimique, 2020 Sidi Thabet (Tunisia); Chevalier, Yves, E-mail: chevalier@lagep.univ-lyon1.fr [Laboratoire d' Automatique et de Génie des Procédés (LAGEP), CNRS UMR 5007, Université Claude Bernard Lyon 1, 69622 Villeurbanne (France)

2013-10-01

Composite materials that combine the lithium exchanging material LiCoO{sub 2} and the conductive polymer poly(aniline) (PANI) have been investigated regarding their possible application to electrode materials of lithium batteries. Such composite materials have been prepared by means of polymerization of aniline in acidic suspensions of LiCoO{sub 2} particles. PANI was synthesized by oxidative polymerization of aniline by ammonium persulfate in the presence of sodium dodecylbenzenesulfonate (SDBS) as a micellar template and dopant. The composite material consisted in LiCoO{sub 2} particles dispersed in a continuous matrix of PANI. The ribbon-like morphology of the powdered material was distinctly different of the morphologies of the parent materials. The conductive material had conductivity close to that of PANI because the LiCoO{sub 2} content of the composite material was low. The presence of the poorly conductive inorganic phase caused a significant loss of conductivity, showing that LiCoO{sub 2} blocked electronic transfers between PANI crystallites. Ammonium persulfate caused the loss of lithium from LiCoO{sub 2} when it was used at high concentration in the polymerization recipe. In this case a new phase made of Co{sub 3}O{sub 4} formed by chemical decomposition of Li{sub x}CoO{sub 2}. Thin films prepared from stable suspensions of composite materials in water show comparable electrical performance to that measured for bulk materials. - Highlights: • LiCoO{sub 2} was incorporated in a conductive polymer matrix made of PANI. • The hybrid material retained the high conductive properties of PANI. • Loss of lithium by persulfate oxidation caused conversion of LiCoO{sub 2} into Co{sub 3}O{sub 4}.

Introduction to mathematical physics methods and concepts

CERN Document Server

Wong, Chun Wa

2013-01-01

Mathematical physics provides physical theories with their logical basis and the tools for drawing conclusions from hypotheses. Introduction to Mathematical Physics explains to the reader why and how mathematics is needed in the description of physical events in space. For undergraduates in physics, it is a classroom-tested textbook on vector analysis, linear operators, Fourier series and integrals, differential equations, special functions and functions of a complex variable. Strongly correlated with core undergraduate courses on classical and quantum mechanics and electromagnetism, it helps the student master these necessary mathematical skills. It contains advanced topics of interest to graduate students on relativistic square-root spaces and nonlinear systems. It contains many tables of mathematical formulas and references to useful materials on the Internet. It includes short tutorials on basic mathematical topics to help readers refresh their mathematical knowledge. An appendix on Mathematica encourages...

A readable introduction to real mathematics

CERN Document Server

Rosenthal, Daniel; Rosenthal, Peter

2014-01-01

Designed for an undergraduate course or for independent study, this text presents sophisticated mathematical ideas in an elementary and friendly fashion. The fundamental purpose of this book is to engage the reader and to teach a real understanding of mathematical thinking while conveying the beauty and elegance of mathematics. The text focuses on teaching the understanding of mathematical proofs. The material covered has applications both to mathematics and to other subjects. The book contains a large number of exercises of varying difficulty, designed to help reinforce basic concepts and to motivate and challenge the reader. The sole prerequisite for understanding the text is basic high school algebra; some trigonometry is needed for Chapters 9 and 12. Topics covered include: * mathematical induction * modular arithmetic * the fundamental theorem of arithmetic * Fermat's little theorem * RSA encryption * the Euclidean algorithm * rational and irrational numbers * complex numbers * cardinality * Euclidean pl...

Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials

Energy Technology Data Exchange (ETDEWEB)

Teixeira, Silvio R., E-mail: rainho@fct.unesp.br [Universidade Estadual Paulista — UNESP, Faculdade de Ciências e Tecnologia — FCT, 19060-900 Presidente Prudente — SP (Brazil); Souza, Agda E. [Universidade Estadual Paulista — UNESP, Faculdade de Ciências e Tecnologia — FCT, 19060-900 Presidente Prudente — SP (Brazil); Carvalho, Claudio L.; Reynoso, Victor C.S. [Universidade Estadual Paulista — UNESP, Faculdade de Engenharia de Ilha Solteira — FEIS, 15385-000 Ilha Solteira – SP (Brazil); Romero, Maximina; Rincón, Jesús Ma. [Instituto de Ciencias de la Construccion Eduardo Torroja — IETCC, CSIC, 28033 Madrid (Spain)

2014-12-15

Glass-ceramic material prepared with sugar cane bagasse ash as one of the raw materials was characterized to determine some important properties for its application as a coating material. X-ray diffraction patterns showed that wollastonite-2M (CaSiO{sub 3}) was the major glass-ceramic phase. The Rietveld method was used to quantify the crystalline (60 wt.%) and vitreous (40 wt.%) phases in the glass-ceramic. The microstructure (determined by scanning electron microscopy) of this material had a marble appearance, showing a microporous network of elongated crystals with some areas with dendritic, feather-like ordering. Microhardness data gave a mean hardness value of 564.4 HV (Vickers-hardness), and light microscopy disclosed a greenish brown colored material with a vitreous luster. - Highlights: • We studied the properties of a glass-ceramic material obtained from sugarcane ash. • This material has the appearance and hardness of natural stones. • A refining method gave information about its amorphous and crystalline phases. • This material has potential to be used as coating plates for buildings.

Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials

International Nuclear Information System (INIS)

Teixeira, Silvio R.; Souza, Agda E.; Carvalho, Claudio L.; Reynoso, Victor C.S.; Romero, Maximina; Rincón, Jesús Ma.

2014-01-01

Glass-ceramic material prepared with sugar cane bagasse ash as one of the raw materials was characterized to determine some important properties for its application as a coating material. X-ray diffraction patterns showed that wollastonite-2M (CaSiO 3 ) was the major glass-ceramic phase. The Rietveld method was used to quantify the crystalline (60 wt.%) and vitreous (40 wt.%) phases in the glass-ceramic. The microstructure (determined by scanning electron microscopy) of this material had a marble appearance, showing a microporous network of elongated crystals with some areas with dendritic, feather-like ordering. Microhardness data gave a mean hardness value of 564.4 HV (Vickers-hardness), and light microscopy disclosed a greenish brown colored material with a vitreous luster. - Highlights: • We studied the properties of a glass-ceramic material obtained from sugarcane ash. • This material has the appearance and hardness of natural stones. • A refining method gave information about its amorphous and crystalline phases. • This material has potential to be used as coating plates for buildings

The preparation and certification of a South African phosphate concentrate for use as a reference material

International Nuclear Information System (INIS)

Hansen, R.G.

1985-01-01

This report describes the preparation, analysis, and certification of South African Reference Material (SARM) 32. The material is a phosphate concentrate from the Phalaborwa deposit, and was supplied by the Phosphate Development Corporation Ltd (Foskor). Eighteen laboratories in eight countries used a variety of analytical techniques to provide the analytical results

Mathematical aspects of ground state tunneling models in luminescence materials

International Nuclear Information System (INIS)

Pagonis, Vasilis; Kitis, George

2015-01-01

Luminescence signals from a variety of natural materials have been known to decrease with storage time at room temperature due to quantum tunneling, a phenomenon known as anomalous fading. This paper is a study of several mathematical aspects of two previously published luminescence models which describe tunneling phenomena from the ground state of a donor–acceptor system. It is shown that both models are described by the same type of integral equation, and two new analytical equations are presented. The first new analytical equation describes the effect of anomalous fading on the dose response curves (DRCs) of naturally irradiated samples. The DRCs in the model were previously expressed in the form of integral equations requiring numerical integration, while the new analytical equation can be used immediately as a tool for analyzing experimental data. The second analytical equation presented in this paper describes the anomalous fading rate (g-Value per decade) as a function of the charge density in the model. This new analytical expression for the g-Value is tested using experimental anomalous fading data for several apatite crystals which exhibit high rate of anomalous fading. The two new analytical results can be useful tools for analyzing anomalous fading data from luminescence materials. In addition to the two new analytical equations, an explanation is provided for the numerical value of a constant previously introduced in the models. - Highlights: • Comparative study of two luminescence models for feldspars. • Two new analytical equations for dose response curves and anomalous fading rate. • The numerical value z=1.8 of previously introduced constant in models explained.

Line integral on engineering mathematics

Science.gov (United States)

Wiryanto, L. H.

2018-01-01

Definite integral is a basic material in studying mathematics. At the level of calculus, calculating of definite integral is based on fundamental theorem of calculus, related to anti-derivative, as the inverse operation of derivative. At the higher level such as engineering mathematics, the definite integral is used as one of the calculating tools of line integral. the purpose of this is to identify if there is a question related to line integral, we can use definite integral as one of the calculating experience. The conclusion of this research says that the teaching experience in introducing the relation between both integrals through the engineer way of thinking can motivate and improve students in understanding the material.

Application of methods of mathematical modeling for determining of radiation-protective characteristics of polystyrene-metal composite materials

International Nuclear Information System (INIS)

Klepikov, V.F.; Prokhorenko, E.M.; Lytvynenko, V.V.; Zakharchenko, A.A.; Nazhmuradov, M.A.

2016-01-01

Radiation safety features of polystyrene steel composite materials were found by means of mathematical modeling techniques. We determined the attenuation of the gamma quantum flux passing through a solid protective layer compared with those attenuation for the bulk protective layer. Change of fractional attenuation of the dose absorbed by 10 and 50 mm thick composites is calculated. Dependence between protective properties of composite and its blend composition was studied. Modifications of technical process of composite materials production were performed. Rotation speed of agitator system was found. It was defined that heating time of polystyrene steel mix is longer than heating time of polystyrene tungstic one. Degree of mix heating and integrity of thermic field on its surface was controlled with the help of IR radiometry methods.

Concepts of mathematical modeling

CERN Document Server

Meyer, Walter J

2004-01-01

Appropriate for undergraduate and graduate students, this text features independent sections that illustrate the most important principles of mathematical modeling, a variety of applications, and classic models. Students with a solid background in calculus and some knowledge of probability and matrix theory will find the material entirely accessible. The range of subjects includes topics from the physical, biological, and social sciences, as well as those of operations research. Discussions cover related mathematical tools and the historical eras from which the applications are drawn. Each sec

The affect of the use of graphical materials on teaching kinematics

International Nuclear Information System (INIS)

Yener, D.

2005-01-01

In this study, a review of literature about graphical materials and kinematics was done. Preparing traditional questions supported by graphical materials on kinematics that applied to 119 first year students at secondary education mathematics department, and physics, chemistry and biology departments at Selcuk University Educational Faculty. The effect of the usage of graphical materials on teaching kinematics were searched. The data obtained from traditional questions and graphical questions were evaluated by using SPSS (Statistical Social Science for Package Program). At the end of this evaluation, it is obvious that if kinematics are taught with graphical materials, students can learn the subject better, thus, they solve the questions easierly and more rapidly. As a result, the students were more successful to solve the questions with graphical materials than traditional questions

[Probability, Cambridge Conference on School Mathematics Feasibility Study No. 7.

Science.gov (United States)

Davis, R.

These materials were written with the aim of reflecting the thinking of the Cambridge Conference on School Mathematics (CCSM) regarding the goals and objectives for school mathematics. They represent a practical response to a proposal by CCSM that some elements of probability be introduced in the elementary grades. These materials provide children…

A survey of collection development for United States Medical Licensing Examination (USMLE) and National Board Dental Examination (NBDE) preparation material.

Science.gov (United States)

Hendrix, Dean; Hasman, Linda

2008-07-01

The research sought to ascertain medical and dental libraries' collection development policies, evaluation methods, purchase decisions, and issues that relate to print and electronic United States Medical Licensing Examination (USMLE) and National Board Dental Examination (NBDE) preparation materials. The investigators surveyed librarians supporting American Association of Medical Colleges (AAMC)-accredited medical schools (n = 58/125) on the USMLE and librarians supporting American Dental Association (ADA)-accredited dental schools (n = 23/56) on the NBDE. The investigators analyzed the data by cross-tabulating and filtering the results using EFM Continuum web survey software. Investigators also surveyed print and electronic USMLE and NBDE preparation materials from 2004-2007 to determine the number of publications and existence of reviews. A majority of responding AAMC libraries (62%, n = 58) provide at least 1 electronic or online USMLE preparation resource and buy an average of 11.6 print USMLE titles annually. Due to a paucity of NBDE print and electronic resources, ADA libraries bought significantly fewer print resources, and only 1 subscribed to an electronic resource. The most often reported evaluation methods for both populations were feedback from medical or dental students, feedback from medical or dental faculty, and online trials. Some AAMC (10%, n = 58) and ADA libraries (39%, n = 23) libraries reported that no evaluation of these materials occured at their libraries. From 2004-2007, publishers produced 45 USMLE preparation resources (total n = 546) to every 1 NBDE preparation resource (total n = 12). Users' needs, institutional missions and goals, financial status, and official collection policies most often underlie decisions to collect or not collect examination preparation materials. Evaluating the quality of examination preparation materials can be problematic due to lack of published reviews, lack of usability testing by libraries, and

13th European Conference on Mathematics for Industry

CERN Document Server

Mattheij, RMM; Peletier, MA

2006-01-01

ECMI has a brand name in Industrial Mathematics and organises successful biannual conferences. This time, the conference on Industrial Mathematics held in Eindhoven in June 2004 Mathematics focused on Aerospace, Electronic Industry, Chemical Technology, Life Sciences, Materials, Geophysics, Financial Mathematics and Water flow. The majority of the invited talks on these topics can be found in these proceedings. Apart form these lectures, a large number of contributed papers and minisymposium papers are included here. They give an interesting and impressive overview of the important place mathematics has achieved in solving all kinds of problems met in industry, and commerce in particular.

A discrete transition to advanced mathematics

CERN Document Server

Richmond, Bettina

2009-01-01

As the title indicates, this book is intended for courses aimed at bridging the gap between lower-level mathematics and advanced mathematics. The text provides a careful introduction to techniques for writing proofs and a logical development of topics based on intuitive understanding of concepts. The authors utilize a clear writing style and a wealth of examples to develop an understanding of discrete mathematics and critical thinking skills. While including many traditional topics, the text offers innovative material throughout. Surprising results are used to motivate the reader. The last thr

Fractal geometry mathematical foundations and applications

CERN Document Server

Falconer, Kenneth

2013-01-01

The seminal text on fractal geometry for students and researchers: extensively revised and updated with new material, notes and references that reflect recent directions. Interest in fractal geometry continues to grow rapidly, both as a subject that is fascinating in its own right and as a concept that is central to many areas of mathematics, science and scientific research. Since its initial publication in 1990 Fractal Geometry: Mathematical Foundations and Applications has become a seminal text on the mathematics of fractals.  The book introduces and develops the general theory and applica

Experiencing Research Practice in Pure Mathematics in a Teacher Training Context

Science.gov (United States)

Knoll, Eva; Ernest, Paul; Morgan, Simon

2004-01-01

This paper presents the early results of an experiment involving a class of elementary student teachers within the context of their mathematics preparation. The motivation of the exercise centered on giving them an experience with mathematical research at their own level and ascertaining its impact on their attitudes and beliefs. The students…

Designing Opportunities for Prospective Teachers to Facilitate Mathematics Discussions in Classrooms

Science.gov (United States)

Hunter, Roberta; Anthony, Glenda

2012-01-01

How prospective teachers can best be prepared to teach effectively in mathematics classrooms is a topic of current concern. In this paper, we describe our exploration of ways in which prospective teachers were supported to translate what they learnt in mathematics methods classes into pedagogical practice. We illustrate how the use of discourse…

Final Technical Report: Mathematical Foundations for Uncertainty Quantification in Materials Design

Energy Technology Data Exchange (ETDEWEB)

Plechac, Petr [Univ. of Delaware, Newark, DE (United States); Vlachos, Dionisios G. [Univ. of Delaware, Newark, DE (United States)

2018-01-23

We developed path-wise information theory-based and goal-oriented sensitivity analysis and parameter identification methods for complex high-dimensional dynamics and in particular of non-equilibrium extended molecular systems. The combination of these novel methodologies provided the first methods in the literature which are capable to handle UQ questions for stochastic complex systems with some or all of the following features: (a) multi-scale stochastic models such as (bio)chemical reaction networks, with a very large number of parameters, (b) spatially distributed systems such as Kinetic Monte Carlo or Langevin Dynamics, (c) non-equilibrium processes typically associated with coupled physico-chemical mechanisms, driven boundary conditions, hybrid micro-macro systems, etc. A particular computational challenge arises in simulations of multi-scale reaction networks and molecular systems. Mathematical techniques were applied to in silico prediction of novel materials with emphasis on the effect of microstructure on model uncertainty quantification (UQ). We outline acceleration methods to make calculations of real chemistry feasible followed by two complementary tasks on structure optimization and microstructure-induced UQ.

Low and High Achivers in Mathematics

DEFF Research Database (Denmark)

Overgaard, Steffen; Tonnesen, Pia Beck

2016-01-01

achievers - within their first years of schooling think mathematically, as background to initiate more effective teaching of the two groups of students. In autumn 2014, 328 Grade 2 students (born in 2006) received an individual special teaching, early intervention, based on the same model and material, 20...... to enhance the teaching of low and high mathematics achievers so as to increase their mathematical knowledge and confidence.......Every mathematics teacher has a challenge in coping with the gap between low and high achievers in the classroom. The purpose of the the project, Early Math Intervention for Marginalized Students, TMTM 2014, is to bring forth knowledge of how these marginalized students - low as well as high...

Preparation of thermo-sensitive slow releasing material and its application in low tar tobacco

Directory of Open Access Journals (Sweden)

Tian Zhong

2017-04-01

Full Text Available To solve some sensory defects such as fragrance deficiency,strong dry sense,poor satisfaction in the development of ultra-low tar tobacco products,we prepared a new thermo sensitive slow releasing composite material with tobacco aroma.The characterization results showed that the as-prepared thermosensitive particles have better aroma enhancing and slow releasing effects.Also,the aroma components of the tip stick containing thermosensitive particles were detected and its sensory quality was evaluated.The results showed that composite tip stick could enhance the aroma and improve the sensory quality of the cigarettes.

Use of CAS in Secondary School: A Factor Influencing the Transition to University-Level Mathematics?

Science.gov (United States)

Varsavsky, Cristina

2012-01-01

Australian secondary school systems offer three levels of senior (year 12) mathematics studies, none of them compulsory: elementary, intermediate and advanced. The intermediate and advanced studies prepare students for further mathematics studies at university level. In the state of Victoria, there are two versions of intermediate mathematics: one…

Mathematical olympiad challenges

CERN Document Server

Andreescu, Titu

2000-01-01

Mathematical Olympiad Challenges is a rich collection of problems put together by two experienced and well-known professors and coaches of the U.S. International Mathematical Olympiad Team. Hundreds of beautiful, challenging, and instructive problems from algebra, geometry, trigonometry, combinatorics, and number theory were selected from numerous mathematical competitions and journals. An important feature of the work is the comprehensive background material provided with each grouping of problems. The problems are clustered by topic into self-contained sections with solutions provided separately. All sections start with an essay discussing basic facts and one or two representative examples. A list of carefully chosen problems follows and the reader is invited to take them on. Additionally, historical insights and asides are presented to stimulate further inquiry. The emphasis throughout is on encouraging readers to move away from routine exercises and memorized algorithms toward creative solutions to open-e...

Opening inquiry mathematics to parents: Can they be engaged as teachers’ partners in mathematical work?

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Ioannis Papadopoulos

2017-12-01

Full Text Available This paper presents a two-stage project designed to develop the partnership between teacher and parents. The project began with a workshop constructed to motivate parents to be interested in doing mathematics in a way that is different from the one they experienced as students and, as a result, to be eager to become involved in the co-production of didactic materials for classroom use. Parents were engaged in real, collaborative, high-level mathematical work as a first step in engaging them as partners in mathematical work with their children.  During this first stage, parents were familiarized with inquiry mathematics tasks to provide them with the foundation necessary to become partners and co-producers during the second. The findings give evidence that the learning of reform math tasks and their co-creation supported teacher and parents’ partnership and that parents were moved mathematically and personally by the experience.

A Guided Tour of Mathematical Methods - 2nd Edition

Science.gov (United States)

Snieder, Roel

2004-09-01

Mathematical methods are essential tools for all physical scientists. This second edition provides a comprehensive tour of the mathematical knowledge and techniques that are needed by students in this area. In contrast to more traditional textbooks, all the material is presented in the form of problems. Within these problems the basic mathematical theory and its physical applications are well integrated. The mathematical insights that the student acquires are therefore driven by their physical insight. Topics that are covered include vector calculus, linear algebra, Fourier analysis, scale analysis, complex integration, Green's functions, normal modes, tensor calculus, and perturbation theory. The second edition contains new chapters on dimensional analysis, variational calculus, and the asymptotic evaluation of integrals. This book can be used by undergraduates, and lower-level graduate students in the physical sciences. It can serve as a stand-alone text, or as a source of problems and examples to complement other textbooks. All the material is presented in the form of problems Mathematical insights are gained by getting the reader to develop answers themselves Many applications of the mathematics are given

Novel mathematic models for quantitative transitivity of quality-markers in extraction process of the Buyanghuanwu decoction.

Science.gov (United States)

Zhang, Yu-Tian; Xiao, Mei-Feng; Deng, Kai-Wen; Yang, Yan-Tao; Zhou, Yi-Qun; Zhou, Jin; He, Fu-Yuan; Liu, Wen-Long

2018-06-01

Nowadays, to research and formulate an efficiency extraction system for Chinese herbal medicine, scientists have always been facing a great challenge for quality management, so that the transitivity of Q-markers in quantitative analysis of TCM was proposed by Prof. Liu recently. In order to improve the quality of extraction from raw medicinal materials for clinical preparations, a series of integrated mathematic models for transitivity of Q-markers in quantitative analysis of TCM were established. Buyanghuanwu decoction (BYHWD) was a commonly TCMs prescription, which was used to prevent and treat the ischemic heart and brain diseases. In this paper, we selected BYHWD as an extraction experimental subject to study the quantitative transitivity of TCM. Based on theory of Fick's Rule and Noyes-Whitney equation, novel kinetic models were established for extraction of active components. Meanwhile, fitting out kinetic equations of extracted models and then calculating the inherent parameters in material piece and Q-marker quantitative transfer coefficients, which were considered as indexes to evaluate transitivity of Q-markers in quantitative analysis of the extraction process of BYHWD. HPLC was applied to screen and analyze the potential Q-markers in the extraction process. Fick's Rule and Noyes-Whitney equation were adopted for mathematically modeling extraction process. Kinetic parameters were fitted and calculated by the Statistical Program for Social Sciences 20.0 software. The transferable efficiency was described and evaluated by potential Q-markers transfer trajectory via transitivity availability AUC, extraction ratio P, and decomposition ratio D respectively. The Q-marker was identified with AUC, P, D. Astragaloside IV, laetrile, paeoniflorin, and ferulic acid were studied as potential Q-markers from BYHWD. The relative technologic parameters were presented by mathematic models, which could adequately illustrate the inherent properties of raw materials

Mathematical competencies and the role of mathematics in physics education: A trend analysis of TIMSS Advanced 1995 and 2008

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Trude Nilsen

2013-10-01

Full Text Available As students advance in their learning of physics over the course of their education, the requirement of mathematical applications in physics-related tasks increases, especially so in upper secondary school and in higher education. Yet there is little empirical work (particularly large-scale or longitudinal on the application of mathematics in physics education compared with the research related to the conceptual knowledge of physics. In order to clarify the nature of mathematics in physics education, we developed a theoretical framework for mathematical competencies pertinent to various physics tasks based on theoretical frameworks from mathematics and physics education. We used this synthesis of frameworks as a basis to create a model for physics competence. The framework also served as a tool for analyzing and categorizing trend items from the international large-scale survey, TIMSS Advanced 1995 and 2008. TIMSS Advanced assessed students in upper secondary school with special preparation in advanced physics and mathematics. We then investigated the changes in achievements on these categorized items across time for nations who participated in both surveys. The results from our analysis indicate that students whose overall physics achievement declined struggled the most with items requiring mathematics, especially items requiring them to handle symbols, such as manipulating equations. This finding suggests the importance of collaboration between mathematics and physics education as well as the importance of traditional algebra for physics education.

Preparation and characterization of nanostructured MWCNT-TiO2 composite materials for photocatalytic water treatment applications

International Nuclear Information System (INIS)

Wang Wendong; Serp, Philippe; Kalck, Philippe; Silva, Claudia Gomes; Faria, Joaquim Luis

2008-01-01

Nanoscale composite materials containing multi-walled carbon nanotubes (MWCNT) and titania were prepared by using a modified sol-gel method. The composites were comprehensively characterized by thermogravimetric analysis, nitrogen adsorption-desorption isotherm, powder X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis absorption spectroscopy. The analysis revealed the presence of titania crystallites of about 7.5 nm aggregated together with MWCNT in particles of 15-20 nm of diameter. The photoactivity of the prepared materials, under UV or visible irradiation, was tested using the conversion of phenol from model aqueous solutions as probe reaction. A synergy effect on the photocatalytic activities observed for the composite catalysts was discussed in terms of a strong interphase interaction between carbon and TiO 2 phases by comparing the different roles of MWCNT in the composite materials

Nature and numbers a mathematical photo shooting

CERN Document Server

Glaeser, Georg

2014-01-01

The book offers 180 pages of spectacular photos and unusual views and insights. Learn to see the world with different eyes and be prepared for many surprises and new facts. The photos give rise to questions that are carefully explained with mathematics.

Lectures on the mathematics of quantum mechanics I

CERN Document Server

Dell'Antonio, Gianfausto

2015-01-01

The first volume (General Theory) differs from most textbooks as it emphasizes the mathematical structure and mathematical rigor, while being adapted to the teaching the first semester of an advanced course in Quantum Mechanics (the content of the book are the lectures of courses actually delivered.). It differs also from the very few texts in Quantum Mechanics that give emphasis to the mathematical aspects because this book, being written as Lecture Notes, has the structure of lectures delivered in a course, namely introduction of the problem, outline of the relevant points, mathematical tools needed, theorems, proofs. This makes this book particularly useful for self-study and for instructors in the preparation of a second course in Quantum Mechanics (after a first basic course). With some minor additions it can be used also as a basis of a first course in Quantum Mechanics for students in mathematics curricula. The second part (Selected Topics) are lecture notes of a more advanced course aimed at giving th...

Using Mathematics, Mathematical Applications, Mathematical Modelling, and Mathematical Literacy: A Theoretical Study

Science.gov (United States)

Mumcu, Hayal Yavuz

2016-01-01

The purpose of this theoretical study is to explore the relationships between the concepts of using mathematics in the daily life, mathematical applications, mathematical modelling, and mathematical literacy. As these concepts are generally taken as independent concepts in the related literature, they are confused with each other and it becomes…

An excursion through elementary mathematics

CERN Document Server

Caminha Muniz Neto, Antonio

2017-01-01

This book provides a comprehensive, in-depth overview of elementary mathematics as explored in Mathematical Olympiads around the world. It expands on topics usually encountered in high school and could even be used as preparation for a first-semester undergraduate course. This first volume covers Real Numbers, Functions, Real Analysis, Systems of Equations, Limits and Derivatives, and much more. As part of a collection, the book differs from other publications in this field by not being a mere selection of questions or a set of tips and tricks that applies to specific problems. It starts from the most basic theoretical principles, without being either too general or too axiomatic. Examples and problems are discussed only if they are helpful as applications of the theory. Propositions are proved in detail and subsequently applied to Olympic problems or to other problems at the Olympic level. The book also explores some of the hardest problems presented at National and International Mathematics Olympiads, as we...

An excursion through elementary mathematics

CERN Document Server

Caminha Muniz Neto, Antonio

This book provides a comprehensive, in-depth overview of elementary mathematics as explored in Mathematical Olympiads around the world. It expands on topics usually encountered in high school and could even be used as preparation for a first-semester undergraduate course. This first volume covers Real Numbers, Functions, Real Analysis, Systems of Equations, Limits and Derivatives, and much more. As part of a collection, the book differs from other publications in this field by not being a mere selection of questions or a set of tips and tricks that applies to specific problems. It starts from the most basic theoretical principles, without being either too general or too axiomatic. Examples and problems are discussed only if they are helpful as applications of the theory. Propositions are proved in detail and subsequently applied to Olympic problems or to other problems at the Olympic level. The book also explores some of the hardest problems presented at National and International Mathematics Olympiads, as we...

Mathematical theory of elasticity of quasicrystals and its applications

CERN Document Server

Fan, Tianyou

2011-01-01

This book presents a clear-cut, strict and systematic mathematical overview of the continuum mechanics of novel materials, condensed matter physics and partial differential equations, and explores the mathematical theory of elasticity of quasicrystals.

Mathematics Education for Engineering Technology Students – A Bridge Too Far?

Directory of Open Access Journals (Sweden)

Noraishiyah Abdullah

2013-03-01

Full Text Available Trying to decide what is best suited for someone or something is an ever enduring task let alone trying to prepare students with the right engineering mind. So ‘how do you build an engineer?’ if that is the right word. What is the right ingredient? Mathematics has been said as the most important foundation in engineers’ life. Curriculum has been developed and reviewed over the years to meet this target. This work explores how much or lack of it has the curriculum prepares the future technologist to face the world of engineering technology as far as mathematics is concerned. Analysis of mathematics lectures, interviews of engineering technologist students and engineering technology subject lecturer is undertaken. Understand what each contributes help in understanding the picture that the current education is painting. Based on the theory of learning, APOS theory helps in explaining how students bridge their knowledge of mathematics when it comes to solving engineering technology problems. The question is, is it a bridge too far? 

ASSESSMENT OF STUDENTS’ PROFESSIONAL COMPETENCIES – THE FUTURE TEACHERS OF MATHEMATICS

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Mariya B. Shashkina

2015-01-01

Full Text Available The aim of the investigation is to describe the authors’ approach to the assessment of the professional competence of the future teacher of mathematics.Methods. The methods involve comparative analysis of the Professional Standard of the teacher and the Federal State Educational Standards in teacher education, as well as the method of predictive analysis of modern educational situation.Results. Qualimetric approach to the structuring of the professional competencies of students is described; it allows concretizing the assessment object, to select the criteria and levels of its formedness, to trace the dynamics of development in the medium of profile preparation of a bachelor. The methodology of assessment a professional-profile competence of the future mathematics teachers is proposed; examples of the competence-assessment tools are provided.Scientific novelty. The study gives a detailed analysis of developing the innovative approach to competencies assessment as metasubject learning outcomes.Practical significance. The proposed method of competencies assessment can be used in the mathematical preparation of the future mathematics teacher, and can serve as a basis for monitoring the professional competencies of students.

Examining Teaching Based on Errors in Mathematics Amongst Pupils with Learning Disabilities

Science.gov (United States)

Magen-Nagar, Noga

2016-01-01

Teaching mathematics while learning from students' mistakes, errors and misconceptions, is most important for meaningful learning. This study was based on intervention programs prepared by preservice teachers. It aimed to examine their knowledge of assessment of errors in mathematics amongst pupils with learning disabilities, and their use as a…

Preparation and Performance of Poly(butyl fumarate-Based Material for Potential Application in LED Encapsulation

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Liang Wang

2017-02-01

Full Text Available A UV-curable poly(butyl fumarate (PBF/poly(propylene fumarate-diacrylate (PPF-DA hybrid material with good performance for LED encapsulation is introduced in the paper. They have been prepared by radical polymerization using PBF and PPF-DA macromers with a UV curing system. PBF and PPF-DA were characterized by Fourier-transform infrared (FT-IR and H-nuclear magnetic resonance (1H NMR. The thermal behavior, optical and mechanical properties of the material were examined by thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, ultraviolet-visible spectroscopy (UV–vis, and a material testing system mechanical testing machine, respectively. The results indicated that the hybrid material has a suitable refractive index (n = 1.537 and high transmittance (99.64% in visible range before/after thermal aging. With the increasing of the double bond ratio from 0.5 to 2, the water absorption ratios of the prepared encapsulation material were 1.22%, 1.87% and 2.88%, respectively. The mechanical property experiments showed that bonding strength was in the range of 1.86–3.40 MPa, tensile-shear strength ranged from 0.84 MPa to 1.57 MPa, and compression strength was in the range of 5.10–27.65 MPa. The cured PBF/PPF-DA hybrid material can be used as a light-emitting diode (LED encapsulant, owing to its suitable refractive index, high transparency, excellent thermal stability, lower water absorption, and good mechanical properties.

Mathematics education, democracy and development: Exploring connections

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Renuka Vithal

2012-12-01

Full Text Available Mathematics education and its links to democracy and development are explored in this article, with specific reference to the case of South Africa. This is done by engaging four key questions. Firstly, the question of whether mathematics education can be a preparation for democracy and include a concern for development, is discussed by drawing on conceptual tools of critical mathematics education and allied areas in a development context. Secondly, the question of how mathematics education is distributed in society and participates in shaping educational possibilities in addressing its development needs and goals is used to examine the issues emerging from mathematics performance in international studies and the national Grade 12 examination; the latter is explored specifically in respect of the South African mathematics curriculum reforms and teacher education challenges. Thirdly, the question of whether a mathematics classroom can be a space for democratic living and learning that equally recognises the importance of issues of development in contexts like South Africa, as a post-conflict society still healing from its apartheid wounds, continuing inequality and poverty, is explored through pedagogies of conflict, dialogue and forgiveness. Finally the question of whether democracy and development can have anything to do with mathematics content matters, is discussed by appropriating, as a metaphor, South Africa’s Truth and Reconciliation Commission’s framework of multiple ‘truths’, to seek links within and across the various forms and movements in mathematics and mathematics education that have emerged in the past few decades.

Micromechanics of heterogeneous materials

CERN Document Server

Buryachenko, Valeriy

2007-01-01

Here is an accurate and timely account of micromechanics, which spans materials science, mechanical engineering, applied mathematics, technical physics, geophysics, and biology. The book features rigorous and unified theoretical methods of applied mathematics and statistical physics in the material science of microheterogeneous media. Uniquely, it offers a useful demonstration of the systematic and fundamental research of the microstructure of the wide class of heterogeneous materials of natural and synthetic nature.

Mathematical Footprints Discovering Mathematics Everywhere

CERN Document Server

Pappas, Theoni

1999-01-01

MATHEMATICAL FOOTPRINTS takes a creative look at the role mathematics has played since prehistoric times, and will play in the future, and uncovers mathematics where you least expect to find it from its many uses in medicine, the sciences, and its appearance in art to its patterns in nature and its central role in the development of computers. Pappas presents mathematical ideas in a readable non-threatening manner. MATHEMATICAL FOOTPRINTS is another gem by the creator of THE MATHEMATICS CALENDAR and author of THE JOY OF MATHEMATICS. "Pappas's books have been gold mines of mathematical ent

Modern mathematics for the engineer second series

CERN Document Server

1961-01-01

This volume and its predecessor were conceived to advance the level of mathematical sophistication in the engineering community. The books particularly focus on material relevant to solving the kinds of mathematical problems regularly confronted by engineers. Suitable as a text for advanced undergraduate and graduate courses as well as a reference for professionals, Volume Two's three-part treatment covers mathematical methods, statistical and scheduling studies, and physical phenomena. Contributions include chapters on chance processes and fluctuations by William Feller, Monte Carlo calculati

Modern mathematics for the engineer first series

CERN Document Server

1956-01-01

This volume and its successor were conceived to advance the level of mathematical sophistication in the engineering community. The books particularly focus on material relevant to solving the kinds of mathematical problems regularly confronted by engineers. Suitable as a text for advanced undergraduate and graduate courses as well as a reference for professionals, Volume One's three-part treatment covers mathematical models, probabilistic problems, and computational considerations. Contributions include chapters on linear and nonlinear oscillations by Solomon Lefschetz, on hyperbolic partial

Improving Instruction in the Mathematics Methods Classroom through Action Research

Science.gov (United States)

Mostofo, Jameel; Zambo, Ron

2015-01-01

There is a continuing emphasis in the United States on improving students' mathematical abilities, and one approach is to better prepare teachers. To investigate the potential usefulness of Lesson Study to better prepare teachers, one author set out to conduct action research on his classroom practice. Specifically, he sought to determine whether…

Preparation and characterization of 304 stainless steel/Q235 carbon steel composite material

Directory of Open Access Journals (Sweden)

Wenning Shen

Full Text Available The composite material of 304 stainless steel reinforced Q235 carbon steel has been prepared by modified hot-rolling process. The resulted material was characterized by scanning electron microscope, three-electrode method, fault current impact method, electrochemical potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy. The results showed that metallurgical bond between the stainless steel layer and carbon steel substrate has been formed. The composite material exhibited good electrical conductivity and thermal stability. The average grounding resistance of the composite material was about 13/20 of dip galvanized steel. There has no surface crack and bubbling formed after fault current impact. The composite material led to a significant decrease in the corrosion current density in soil solution, compared with that of hot dip galvanized steel and bare carbon steel. On the basis polarization curve and EIS analyses, it can be concluded that the composite material showed improved anti-corrosion property than hot-dip galvanized steel. Keywords: Stainless steel, Carbon steel, Anti-corrosion, Conductivity, Electrochemical, EIS

DEVELOPMENT OF MAPLE IN TRAINING HIGHER MATHEMATICS

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Volodymyr M. Mykhalevych

2011-03-01

Full Text Available The relevance of the material presented in this paper due to the need to develop and implement new information technologies in teaching higher mathematics with the use of systems of symbolic mathematics. Brief analysis of the Maple and Mathematica is given. The basic results of authors on working out of a training complex on higher mathematics are given. The complex was created in an environment of symbolic mathematics Maple. Procedure simulators, which give the whole process of model solutions of mathematical problems are a major element of the complex. The results of such procedures for typical problems from different sections of higher mathematics in accordance with the program for technical universities are represented. Questions the benefits and methods of using such programs, in particular those related to deficits of licensed copies of Maple was touched.

Material tools and meaning formation in mathematics

DEFF Research Database (Denmark)

Johansen, Mikkel Willum; Misfeldt, Morten

revealed several new aspects. For this presentation we will especially focus on how mathematicians use external representations as a way to familiarize themselves with, or ascribe meaning to the mathematical objects they are working with, and how this process plays an important role in the heuristic...... for several different purposes and different tools are used at different stages of the working process. In our talk we will focus on the use of external representations such as symbols, figures and diagrams, and we will explain the role played by such representations in the cognitive practice of working...

Mathematics, Vol. 2.

Science.gov (United States)

Bureau of Naval Personnel, Washington, DC.

The second of three volumes of a mathematics training course for Navy personnel, this document contains material primarily found at the college level. Beginning with logarithms and trigonometry, the text moves into vectors and static equilibrium (physics). Coordinate geometry, conic sections, and the tangents, normals, and slopes of curves follow.…

Mathematical aspects of quantum field theory

CERN Document Server

de Faria, Edson

2010-01-01

Over the last century quantum field theory has made a significant impact on the formulation and solution of mathematical problems and inspired powerful advances in pure mathematics. However, most accounts are written by physicists, and mathematicians struggle to find clear definitions and statements of the concepts involved. This graduate-level introduction presents the basic ideas and tools from quantum field theory to a mathematical audience. Topics include classical and quantum mechanics, classical field theory, quantization of classical fields, perturbative quantum field theory, renormalization, and the standard model. The material is also accessible to physicists seeking a better understanding of the mathematical background, providing the necessary tools from differential geometry on such topics as connections and gauge fields, vector and spinor bundles, symmetries and group representations.

Mathematics and Mechanics of Granular Materials

CERN Document Server

Hill, James M

2005-01-01

Granular or particulate materials arise in almost every aspect of our lives, including many familiar materials such as tea, coffee, sugar, sand, cement and powders. At some stage almost every industrial process involves a particulate material, and it is usually the cause of the disruption to the smooth running of the process. In the natural environment, understanding the behaviour of particulate materials is vital in many geophysical processes such as earthquakes, landslides and avalanches. This book is a collection of current research from some of the major contributors in the topic of modelling the behaviour of granular materials. Papers from every area of current activity are included, such as theoretical, numerical, engineering and computational approaches. This book illustrates the numerous diverse approaches to one of the outstanding problems of modern continuum mechanics.

Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

Science.gov (United States)

Čapek, Jaroslav; Vojtěch, Dalibor

2014-02-01

There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium. © 2013.

Sol-gel derived electrode materials for supercapacitor applications

Science.gov (United States)

Lin, Chuan

1998-12-01

Electrochemical capacitors have been receiving increasing interest in recent years for use in energy storage systems because of their high energy and power density and long cycle lifes. Possible applications of electrochemical capacitors include high power pulsed lasers, hybrid power system for electric vehicles, etc. In this dissertation, the preparation of electrode materials for use as electrochemical capacitors has been studied using the sol-gel process. The high surface area electrode materials explored in this work include a synthetic carbon xerogel for use in a double-layer capacitor, a cobalt oxide xerogel for use in a pseudocapacitor, and a carbon-ruthenium xerogel composite, which utilizes both double-layer and faradaic capacitances. The preparation conditions of these materials were investigated in detail to maximize the surface area and optimize the pore size so that more energy could be stored while minimizing mass transfer limitations. The microstructures of the materials were also correlated with their performance as electrochemical capacitors to improve their energy and power densities. Finally, an idealistic mathematical model, including both double-layer and faradaic processes, was developed and solved numerically. This model can be used to perform the parametric studies of an electrochemical capacitor so as to gain a better understanding of how the capacitor works and also how to improve cell operations and electrode materials design.

Basic engineering mathematics

CERN Document Server

Bird, John

2014-01-01

Introductory mathematics written specifically for students new to engineering Now in its sixth edition, Basic Engineering Mathematics is an established textbook that has helped thousands of students to succeed in their exams. John Bird's approach is based on worked examples and interactive problems. This makes it ideal for students from a wide range of academic backgrounds as the student can work through the material at their own pace. Mathematical theories are explained in a straightforward manner, being supported by practical engineering examples and applications in order to ensure that readers can relate theory to practice. The extensive and thorough topic coverage makes this an ideal text for introductory level engineering courses. This title is supported by a companion website with resources for both students and lecturers, including lists of essential formulae, multiple choice tests, full solutions for all 1,600 further questions contained within the practice exercises, and biographical information on t...

Heterogeneous Materials I and Heterogeneous Materials II

International Nuclear Information System (INIS)

Knowles, K M

2004-01-01

In these two volumes the author provides a comprehensive survey of the various mathematically-based models used in the research literature to predict the mechanical, thermal and electrical properties of hetereogeneous materials, i.e., materials containing two or more phases such as fibre-reinforced polymers, cast iron and porous ceramic kiln furniture. Volume I covers linear properties such as linear dielectric constant, effective electrical conductivity and elastic moduli, while Volume II covers nonlinear properties, fracture and atomistic and multiscale modelling. Where appropriate, particular attention is paid to the use of fractal geometry and percolation theory in describing the structure and properties of these materials. The books are advanced level texts reflecting the research interests of the author which will be of significant interest to research scientists working at the forefront of the areas covered by the books. Others working more generally in the field of materials science interested in comparing predictions of properties with experimental results may well find the mathematical level quite daunting initially, as it is apparent that the author assumes a level of mathematics consistent with that taught in final year undergraduate and graduate theoretical physics courses. However, for such readers it is well worth persevering because of the in-depth coverage to which the various models are subjected, and also because of the extensive reference lists at the back of both volumes which direct readers to the various source references in the scientific literature. Thus, for the wider materials science scientific community the two volumes will be a valuable library resource. While I would have liked to see more comparison with experimental data on both ideal and 'real' heterogeneous materials than is provided by the author and a discussion of how to model strong nonlinear current--voltage behaviour in systems such as zinc oxide varistors, my overall

Bulk-scaffolded hydrogen storage and releasing materials and methods for preparing and using same

Science.gov (United States)

Autrey, S Thomas [West Richland, WA; Karkamkar, Abhijeet J [Richland, WA; Gutowska, Anna [Richland, WA; Li, Liyu [Richland, WA; Li, Xiaohong S [Richland, WA; Shin, Yongsoon [Richland, WA

2011-06-21

Compositions are disclosed for storing and releasing hydrogen and methods for preparing and using same. These hydrogen storage and releasing materials exhibit fast release rates at low release temperatures without unwanted side reactions, thus preserving desired levels of purity and enabling applications in combustion and fuel cell applications.

What is the problem in problem-based learning in higher education mathematics

Science.gov (United States)

Dahl, Bettina

2018-01-01

Problem and Project-Based Learning (PBL) emphasise collaborate work on problems relevant to society and emphases the relation between theory and practice. PBL fits engineering students as preparation for their future professions but what about mathematics? Mathematics is not just applied mathematics, but it is also a body of abstract knowledge where the application in society is not always obvious. Does mathematics, including pure mathematics, fit into a PBL curriculum? This paper argues that it does for two reasons: (1) PBL resembles the working methods of research mathematicians. (2) The concept of society includes the society of researchers to whom theoretical mathematics is relevant. The paper describes two cases of university PBL projects in mathematics; one in pure mathematics and the other in applied mathematics. The paper also discusses that future engineers need to understand the world of mathematics as well as how engineers fit into a process of fundamental-research-turned-into-applied-science.

An investigation of elementary preservice teachers’ self-efficacy for teaching mathematics

Directory of Open Access Journals (Sweden)

Rebecca McMahon Giles

2016-12-01

Full Text Available Research has consistently shown that teacher efficacy is related to a variety of desirable student outcomes, thus, making teacher efficacy an important factor in high quality mathematics instruction. The purpose of this study was to determine elementary preservice teachers’ self-efficacy beliefs related to teaching mathematics. Forty-one participants from a single university responded to the Mathematics Teaching Efficacy Beliefs Instrument (MTEBI after completing a constructivist-based elementary mathematics methods course prior to student teaching. The MTEBI is 21-item survey using a 5-point, forced choice Likert-like scale to provide an individual's perceptions of mathematics teaching efficacy beliefs on two subscales—Personal Mathematics Teaching Efficacy Belief (PMTE and Mathematics Teaching Outcome Expectancy (MTOE. Responses on the PMTE subscale (Mean = 51.08, SD=5.171 indicate that the respondents’ personal mathematics teach efficacy is positive. Participants’ responses (Mean = 29.32, SD = 3.29 on the MTOE subscale indicate positive expectations of students' mathematics learning. Attending to preservice teacher efficacy is worthy of examination. Teacher preparation programs must identify opportunities to positively impact mathematics teaching efficacy of preservice teachers.

Preparation of Al/Si functionally graded materials using ultrasonic separation method

Directory of Open Access Journals (Sweden)

Zhang Zhongtao

2008-08-01

Full Text Available Functionally graded materials (FGM have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare Al/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a large quantity of primary Si gradually to the eutectic, and fi nally to the hypoeutectic with numerous primary Al dendrites. The distribution of primary Si and microhardness of the FGM sample also presented graded characteristics, resulting that the wear resistance of the FGM sample decreased from top to bottom. Preliminary discussion was made on the mechanism of the formation of Al/Si FGM.

To what extent do student teachers develop their mathematical problem solving ability by self-study?

OpenAIRE

Kool, Marjolein; Keijzer, Ronald

2017-01-01

A primary teacher needs mathematical problem solving ability. That is why Dutch student teachers have to show this ability in a nationwide mathematics test that contains many non-routine problems. Most student teachers prepare for this test by working on their own solving test-like problems. To what extent does these individual problem solving activities really contribute to their mathematical problem solving ability? Developing mathematical problem solving ability requires reflective mathema...

Mathematical History: Activities, Puzzles, Stories, and Games.

Science.gov (United States)

Mitchell, Merle

Based on the history of mathematics, these materials have been planned to enrich the teaching of mathematics in grades four, five, and six. Puzzles and games are based on stories about topics such as famous mathematicians, numerals of ancient peoples, and numerology. The sheets are arranged by grade level and are designed for easy duplication.…

Mathematical optics classical, quantum, and computational methods

CERN Document Server

Lakshminarayanan, Vasudevan

2012-01-01

Going beyond standard introductory texts, Mathematical Optics: Classical, Quantum, and Computational Methods brings together many new mathematical techniques from optical science and engineering research. Profusely illustrated, the book makes the material accessible to students and newcomers to the field. Divided into six parts, the text presents state-of-the-art mathematical methods and applications in classical optics, quantum optics, and image processing. Part I describes the use of phase space concepts to characterize optical beams and the application of dynamic programming in optical wave

Interpreting Mathematics Scores on the New Jersey College Basic Skills Placement Test.

Science.gov (United States)

Dass, Jane; Pine, Charles

The New Jersey College Basic Skills Placement Test (NJCBSPT) is designed to measure certain basic language and mathematics skills of students entering New Jersey colleges. The primary purpose of the two mathematics sections is to determine whether students are prepared to begin certain college-level work without a handicap in computation or…

International Comparisons of Foundation Phase Number Domain Mathematics Knowledge and Practice Standards

Science.gov (United States)

Human, Anja; van der Walt, Marthie; Posthuma, Barbara

2015-01-01

Poor mathematics performance in schools is both a national and an international concern. Teachers ought to be equipped with relevant subject matter knowledge and pedagogical content knowledge as one way to address this problem. However, no mathematics knowledge and practice standards have as yet been defined for the preparation of Foundation Phase…

Utility-value intervention with parents increases students' STEM preparation and career pursuit.

Science.gov (United States)

Rozek, Christopher S; Svoboda, Ryan C; Harackiewicz, Judith M; Hulleman, Chris S; Hyde, Janet S

2017-01-31

During high school, developing competence in science, technology, engineering, and mathematics (STEM) is critically important as preparation to pursue STEM careers, yet students in the United States lag behind other countries, ranking 35th in mathematics and 27th in science achievement internationally. Given the importance of STEM careers as drivers of modern economies, this deficiency in preparation for STEM careers threatens the United States' continued economic progress. In the present study, we evaluated the long-term effects of a theory-based intervention designed to help parents convey the importance of mathematics and science courses to their high-school-aged children. A prior report on this intervention showed that it promoted STEM course-taking in high school; in the current follow-up study, we found that the intervention improved mathematics and science standardized test scores on a college preparatory examination (ACT) for adolescents by 12 percentile points. Greater high-school STEM preparation (STEM course-taking and ACT scores) was associated with increased STEM career pursuit (i.e., STEM career interest, the number of college STEM courses, and students' attitudes toward STEM) 5 y after the intervention. These results suggest that the intervention can affect STEM career pursuit indirectly by increasing high-school STEM preparation. This finding underscores the importance of targeting high-school STEM preparation to increase STEM career pursuit. Overall, these findings demonstrate that a motivational intervention with parents can have important effects on STEM preparation in high school, as well as downstream effects on STEM career pursuit 5 y later.

The SAMPLE experience: The development of a rich media online mathematics learning environment

OpenAIRE

Chang, Jen

2006-01-01

This report documents the development of Sample Architecture for Mathematically Productive Learning Experiences (SAMPLE), a rich media, online, mathematics learning environment created to meet the needs of middle school educators. It explores some of the current pedagogical challenges in mathematics education, and their amplified impacts when coupled with under-prepared teachers, a decidedly wide-spread phenomenon. The SAMPLE publishing experience is discussed in terms of its instructional de...

Mesopotamian Mathematics, Seen “from the Inside” (by Assyriologists) and “from the Outside” (by Historians of Mathematics)

DEFF Research Database (Denmark)

Høyrup, Jens

2016-01-01

Since the 1950s, “Babylonian mathematics” has often served to open expositions of the general history of mathematics. Since it is written in a language and a script which only specialists understand, it has always been dealt with differently by the “insiders”, the Assyriologists who approached...... the texts where it manifests itself as philologists and historians of Mesopotamian culture, and by “outsiders”, historians of mathematics who had to rely on second-hand understanding of the material (actually, of as much of this material as they wanted to take into account), but who saw it as a constituent...... of the history of mathematics. The article deals with how these different approaches have looked in various periods: pre-decipherment speculations; the early period of deciphering, 1847–1929; the “golden decade”, 1929–1938, where workers with double competence (primarily Neugebauer and Thureau-Dangin) attacked...

Mathematical foundation of computer science

CERN Document Server

Singh, YN

2005-01-01

The interesting feature of this book is its organization and structure. That consists of systematizing of the definitions, methods, and results that something resembling a theory. Simplicity, clarity, and precision of mathematical language makes theoretical topics more appealing to the readers who are of mathematical or non-mathematical background. For quick references and immediate attentions¾concepts and definitions, methods and theorems, and key notes are presented through highlighted points from beginning to end. Whenever, necessary and probable a visual approach of presentation is used. The amalgamation of text and figures make mathematical rigors easier to understand. Each chapter begins with the detailed contents, which are discussed inside the chapter and conclude with a summary of the material covered in the chapter. Summary provides a brief overview of all the topics covered in the chapter. To demonstrate the principles better, the applicability of the concepts discussed in each topic are illustrat...

The application of prepared porous carbon materials: Effect of different components on the heavy metal adsorption.

Science.gov (United States)

Song, Min; Wei, Yuexing; Yu, Lei; Tang, Xinhong

2016-06-01

In this study, five typical municipal solid waste (MSW) components (tyres, cardboard, polyvinyl chloride (PVC), acrylic textile, toilet paper) were used as raw materials to prepare four kinds of MSW-based carbon materials (paperboard-based carbon materials (AC1); the tyres and paperboard-based carbon materials (AC2); the tyres, paperboard and PVC-based carbon materials (AC3); the tyres, paperboard, toilet paper, PVC and acrylic textile-based carbon materials (AC4)) by the KOH activation method. The characteristic results illustrate that the prepared carbon adsorbents exhibited a large pore volume, high surface area and sufficient oxygen functional groups. Furthermore, the application of AC1, AC2, AC3, AC4 on different heavy metal (Cu(2+), Zn(2+), Pb(2+), Cr(3+)) removals was explored to investigate their adsorption properties. The effects of reaction time, pH, temperature and adsorbent dosage on the adsorption capability of heavy metals were investigated. Comparisons of heavy metal adsorption on carbon of different components were carried out. Among the four samples, AC1 exhibits the highest adsorption capacity for Cu(2+); the highest adsorption capacities of Pb(2+) and Zn(2+) are obtained for AC2; that of Cr(3+) are obtained for AC4. In addition, the carbon materials exhibit better adsorption capability of Cu(2+) and Pb(2+) than the other two kind of metal ions (Zn(2+) and Cr(3+)). © The Author(s) 2016.

An Investigation of Mathematical Knowledge Related to Mathematics Teachers' Basic Concepts in Sets Unit

Directory of Open Access Journals (Sweden)

Nurullah YAZICI

2017-05-01

Full Text Available This research was conducted in order to examine the subject matter of Mathematics teachers in the context of "Mathematical Knowledge For Teaching" (MKT model of "Basic Concepts in Sets" which is the first topic of the 9th class "Sets". The study group, which is one of the qualitative research methods, used the case study design, constitutes 5 mathematics teachers who work in different education levels (primary and secondary education in the academic year of 2015-2016. Open-ended questions and semi-structured interview form developed by the researcher were used for data collection. A descriptive analysis technique was used to analyze the data obtained through interviews. While analyzing the data, teacher and student textbooks, which were prepared by the Ministry of National Education for the purpose of teaching in 2015-2016 academic year, were taken as a reference. According to the research findings, it was determined that the teachers had deficiencies in the subject field of "Basic Concepts in the Sets" and had superficial knowledge rather than in depth knowledge.

Preparation of thermoluminescent materials

International Nuclear Information System (INIS)

1976-01-01

Thermoluminescent materials have been found to be suitable for measuring long term exposures to low level ionizing radiation. Oxyhalides of lanthanum, gadolinium and yttrium, including the oxychlorides and oxybromides are activated with terbium and have been found to be most efficient oxygendominated phosphors having thermoradiant efficiencies with excitation by low level ionizing radiation. Thermoluminescence response increases when the previous materials have hafnium and zirconium additives

Developing Teaching Material Software Assisted for Numerical Methods

Science.gov (United States)

Handayani, A. D.; Herman, T.; Fatimah, S.

2017-09-01

The NCTM vision shows the importance of two things in school mathematics, which is knowing the mathematics of the 21st century and the need to continue to improve mathematics education to answer the challenges of a changing world. One of the competencies associated with the great challenges of the 21st century is the use of help and tools (including IT), such as: knowing the existence of various tools for mathematical activity. One of the significant challenges in mathematical learning is how to teach students about abstract concepts. In this case, technology in the form of mathematics learning software can be used more widely to embed the abstract concept in mathematics. In mathematics learning, the use of mathematical software can make high level math activity become easier accepted by student. Technology can strengthen student learning by delivering numerical, graphic, and symbolic content without spending the time to calculate complex computing problems manually. The purpose of this research is to design and develop teaching materials software assisted for numerical method. The process of developing the teaching material starts from the defining step, the process of designing the learning material developed based on information obtained from the step of early analysis, learners, materials, tasks that support then done the design step or design, then the last step is the development step. The development of teaching materials software assisted for numerical methods is valid in content. While validator assessment for teaching material in numerical methods is good and can be used with little revision.

Development of resistance welding process. 4. Preparation of pressuring enclosed creep test specimen of 7A material

International Nuclear Information System (INIS)

Endo, Hideo; Seki, Masayuki; Ishibashi, Fujio; Hirako, Kazuhito; Tsukada, Tatsuya

2001-02-01

Mechanical strength in the position welded by resistance welding system was examined in 1999. The test specimens were destroyed in the welding position in a shorter time than expected in the creep test. Therefore, test specimens were prepared to evaluate the cause of destruction. Inner-pressure enclosed creep test specimens were prepared by resistance welding method. Cladding material with low deviation of thickness and high re-crystallization rate was used. Heat treatment after resistance welding was performed to remove the influence of residual stress and the precipitation of carbides. (1) Before preparation of specimens, the welding condition was fixed. Three test specimens were prepared. Two specimens without heat treatment were transported to MMS in Oarai Engineering Center on Aug. 4, 2000. One specimen with heat treatment was transported to MMS after evaluating the residual stress to get optimum heat treatment condition. (2) Specimens were prepared with welding end plugs to both ends of ferritic ODS cladding. Enclosing sides were welded with highly strong Ferritic/Martensitic steel end plugs. The other sides were welded with ferritic ODS end plugs. (3) Some kinds of electrical wave data were obtained during performing welding. Welding position was evaluated with supersonic detector after performing welding. (4) Mechanical strength of welding position in high temperature 800degC was confirmed to be equal to or larger than that of cladding material. The highly qualified specimens in the present were successfully prepared. (author)

Stealing from Physics: Modeling with Mathematical Functions in Data-Rich Contexts

Science.gov (United States)

Erickson, Tim

2006-01-01

In the course of a project to create physics education materials for secondary schools in the USA we have, not surprisingly, had insights into how students develop certain mathematical understandings. Some of these translate directly into the mathematics classroom. With our materials, students get data from a variety of sources, data that arise in…

Preparation and Characterization of Lignin-based Membrane Material

Directory of Open Access Journals (Sweden)

Shuai Wang

2015-07-01

Full Text Available Lignin-based membrane material was prepared from lignosulfonate extracted from sulfite pulping. The effects of formaldehyde, polyvinyl alcohol (PVA, urea, borax, glutaraldehyde (GD, and dimethyl phthalate (DMP on tensile strength and water absorption were investigated. The experimental results showed that the optimum conditions were as follows: a reaction temperature of 85 °C, 22.22 wt.% lignosulfonate, 1.59 wt.% borax, 22.22 wt.% urea, 31.75 wt.% formaldehyde, 22.22 wt.% PVA, 32.32 wt.% GD (to PVA glue, and 32.32 wt.% DMP (to PVA glue. Under these conditions, the tensile strength reached 2.2 ×104 Pa and the water absorption was 35.2%. The products were characterized by Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. The results showed that the product components were compatible in this system, and the introduction of cross-linking agents may have resulted in a decrease in pore size.

Quality assessment of organic coffee beans for the preparation of a candidate reference material

International Nuclear Information System (INIS)

Tagliaferro, F.S.; Nadai Fernandes de, E.A.; Bacchi, M.A.

2006-01-01

A random sampling was carried out in the coffee beans collected for the preparation of the organic green coffee reference material in view of assessing the homogeneity and the presence of soil as impurity. Fifteen samples were taken for the between-sample homogeneity evaluation. One of the samples was selected and 10 test portions withdrawn for the within-sample homogeneity evaluation. Br, Ca, Co, Cs, Fe, K, Na, Rb, Sc and Zn were determined by instrumental neutron activation analysis (INAA). The F-test demonstrated that the material is homogeneous for Ca, Co, Cs, K and Sc, but not homogeneous for Br, Fe, Na, Rb and Zn. Results of terrigenous elements suggested negligible soil contamination in the raw material. (author)

Reliability of Scores Obtained from Self-, Peer-, and Teacher-Assessments on Teaching Materials Prepared by Teacher Candidates

Science.gov (United States)

Nalbantoglu Yilmaz, Funda

2017-01-01

This study aims to determine the reliability of scores obtained from self-, peer-, and teacher-assessments in terms of teaching materials prepared by teacher candidates. The study group of this research constitutes 56 teacher candidates. In the scope of research, teacher candidates were asked to develop teaching material related to their study.…

Developing Mathematical Content Knowledge for Teaching: One Preservice Teacher and Her Planning

Science.gov (United States)

Wilson, Susanna

2016-01-01

This paper describes how a new pre-service teacher engaged with mathematical content in order to learn it for teaching, during practicum. The results show that the PST learned mathematical content by initiating and carrying out a preparation phase prior to planning. This phase involved searching through internet sites and making notes that were…

Influence of interface preparation on minority carrier lifetime for low bandgap tandem solar cell materials

Energy Technology Data Exchange (ETDEWEB)

Szabo, Nadine; Sagol, B. Erol; Seidel, Ulf; Schwarzburg, Klaus; Hannappel, Thomas [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany)

2010-07-01

III-V semiconductor compounds grown by MOVPE are implemented in todays state-of-the-art third generation multi-junction solar cells. The current record multi junction solar cell grown on germanium, having Ge, Ga(In)As and GaInP as subcells, reached a record efficiency of 41.6%. The efficiency of these multi junction solar cells could be significantly increased, if its low bandgap Ge subcell would be replaced by a more efficient tandem. For this purpose the low bandgap materials InGaAs and InGaAsP are suitable. The bandgap composition of these materials allows a better yield of the solar spectrum. Based on InGaAs/InGaAsP absorber materials we have developed a low bandgap tandem solar cell with optimized bandgaps. Results of time resolved photoluminescence (TRPL) for the IR-bandgap compounds InGaAsP (1.03 eV)/InGaAs (0.73 eV) are presented. The lifetime of minority carriers is one of the most important properties of solar cell absorber materials. We show on the example of the low band gap tandem cell how the choice of the materials, the quality of the bulk, the optimization of the band gap energies and the preparation of the critical interfaces are essential to build a high efficiency solar cell. The quality of the bulk and the preparation of the critical interfaces are essential for the growth of the double heterostructure (DHS).

Mathematical modelling in solid mechanics

CERN Document Server

Sofonea, Mircea; Steigmann, David

2017-01-01

This book presents new research results in multidisciplinary fields of mathematical and numerical modelling in mechanics. The chapters treat the topics: mathematical modelling in solid, fluid and contact mechanics nonconvex variational analysis with emphasis to nonlinear solid and structural mechanics numerical modelling of problems with non-smooth constitutive laws, approximation of variational and hemivariational inequalities, numerical analysis of discrete schemes, numerical methods and the corresponding algorithms, applications to mechanical engineering numerical aspects of non-smooth mechanics, with emphasis on developing accurate and reliable computational tools mechanics of fibre-reinforced materials behaviour of elasto-plastic materials accounting for the microstructural defects definition of structural defects based on the differential geometry concepts or on the atomistic basis interaction between phase transformation and dislocations at nano-scale energetic arguments bifurcation and post-buckling a...