Basic study on electrically stimulated luminescence (ESL) as a dosimetry and dating method

International Nuclear Information System (INIS)

Sato, H.; Yamanaka, C.; Ikeya, M.

2003-01-01

Electrically stimulated luminescence (ESL) of calcium carbonate has been studied for application as dosimetry and dating. A powdered calcium carbonate was sandwiched by electrodes, which supplied electric field. Luminescence and surface current through a powdered sample were measured using a photomultiplier and a digital multimeter, respectively. A linear dependence of ESL on the absorbed dose by γ-rays was found when the applied voltage was below the breakdown threshold. Reciprocal electric charges through the sample had also linear relation with the absorbed dose. We propose that the luminescence and electric charge under intense electric field in calcium carbonate become new methods for dosimetry and dating on the basis of the surface defects of the calcium carbonate grains produced by the irradiation of γ-rays

Fluency First: Reversing the Traditional ESL Sequence.

Science.gov (United States)

MacGowan-Gilhooly, Adele

1991-01-01

Describes an ESL department's whole language approach to writing and reading, replacing its traditional grammar-based ESL instructional sequence. Reports the positive quantitative and qualitative results of the first three years of using the new approach. (KEH)

Professionalization and Exclusion in ESL Teaching

Science.gov (United States)

Breshears, Sherry

2004-01-01

As ESL/EFL teachers, how do we fit into the spectrum between unskilled workers and highly trained professionals? This article examines three features of the traditional professions and applies them to the ESL/EFL context. It considers problems with the lack of mandatory standardized certification, critically assesses attachment to the university,…

Large-deformation analysis of the elastic recoil of fibre layers in a Brinkman medium with application to the endothelial glycocalyx

NARCIS (Netherlands)

Han, Y. F.; Weinbaum, S.; Spaan, J. A. E.; Vink, H.

2006-01-01

There is wide interest in the role of the endothelial surface layer (ESL) in transmitting blood shear stress to the intracellular cytoskeleton of the endothelial cell. However, very little is known about the mechanical properties of the glycocalyx or the flexural rigidity of the core proteins that

Standards for Adult Education ESL Programs

Science.gov (United States)

TESOL Press, 2013

2013-01-01

What are the components of a quality education ESL program? TESOL's "Standards for Adult Education ESL Programs" answers this question by defining quality components from a national perspective. Using program indicators in eight distinct areas, the standards can be used to review an existing program or as a guide in setting up a new…

Redesigning nursing tutorials for ESL students: a pilot study.

Science.gov (United States)

San Miguel, Caroline; Townsend, Lisa; Waters, Cheryl

2013-04-01

Increased enrolments of Bachelor of Nursing (BN) students who speak English as a second language (ESL) can help create a multilingual and culturally diverse workforce that is better prepared to meet the needs of increasingly diverse health populations. However, although ESL enrolments are increasing, attrition rates for ESL students tend to be higher than those of native speakers of English, partly due to academic failure. At the same time, concerns have been expressed in some quarters about the low levels of English language of entering students. As it is unlikely that language entry levels to university will be raised, sustainable programmes that help ESL students better meet the academic challenges they may face need to be developed. So far, models of ESL support have been mostly an adjunct to their degree, voluntary and not well attended. This paper discusses a model using tutorials integrated into the first year nursing curriculum that were specifically designed for ESL students with low levels of English language proficiency. The paper also examines students' perceptions of such tutorials, which they found beneficial to their learning.

Designing Websites for ESL Learners: A Usability Testing Study

Science.gov (United States)

Liu, Min; Traphagan, Tomoko; Huh, Jin; Koh, Young Ihn; Choi, Gilok; McGregor, Allison

2008-01-01

The purpose of this paper is to report on a usability study for ESL websites conducted to gain insights from learners of English as a second language (ESL) as they interacted with specific sites. Five carefully selected ESL sites were tested by 10 different users generating a total of fifty testing sessions. Two major research questions guided the…

Collaboration Model for ESL and Content Teachers

Science.gov (United States)

Broer, Kathleen

2013-01-01

This study will examine strategies that ESL teachers and content teachers can use to help middle school ESL students acquire science vocabulary and meta-cognitive strategies for writing skills in non-fiction text forms. Two appendixes are included. (Contains 3 figures and 2 footnotes.)

Single-layer model for surface roughness.

Science.gov (United States)

Carniglia, C K; Jensen, D G

2002-06-01

Random roughness of an optical surface reduces its specular reflectance and transmittance by the scattering of light. The reduction in reflectance can be modeled by a homogeneous layer on the surface if the refractive index of the layer is intermediate to the indices of the media on either side of the surface. Such a layer predicts an increase in the transmittance of the surface and therefore does not provide a valid model for the effects of scatter on the transmittance. Adding a small amount of absorption to the layer provides a model that predicts a reduction in both reflectance and transmittance. The absorbing layer model agrees with the predictions of a scalar scattering theory for a layer with a thickness that is twice the rms roughness of the surface. The extinction coefficient k for the layer is proportional to the thickness of the layer.

An Empirical Investigation into Nigerian ESL Learners ...

African Journals Online (AJOL)

General observations indicate that ESL learners in Nigeria tend to manifest fear and anxiety in grammar classes, which could influence their performance negatively or positively. This study examines empirically some of the reasons for some ESL learners' apprehension of grammar classes. The data for the study were ...

Reading and esl writers Reading and esl writers

Directory of Open Access Journals (Sweden)

John R. Edlund

2008-04-01

Full Text Available Whether the student population consists of basic writers, non-native speakers, or well-prepared freshmen and whether the primary goal of the class is improvement in writing ability, language and vocabulary acquisition, or critical thinking skills, there is considerable evidence that substantial amounts of reading arc an essential component of the course (See Krashen Writing: Research, Theory and Applications for a summary. This is especially true in the ESL composition class, where language acquisition is still a major factor in the student's success as a writer. Whether the student population consists of basic writers, non-native speakers, or well-prepared freshmen and whether the primary goal of the class is improvement in writing ability, language and vocabulary acquisition, or critical thinking skills, there is considerable evidence that substantial amounts of reading arc an essential component of the course (See Krashen Writing: Research, Theory and Applications for a summary. This is especially true in the ESL composition class, where language acquisition is still a major factor in the student's success as a writer.

Ouch! Or ESL and the Glass Ceiling.

Science.gov (United States)

Migliacci, Naomi

The realities of the glass ceiling, which prevents qualified women, minorities, and many English-as-a-Second-Language (ESL) students from advancement and promotion, are rarely discussed in English for Special Purposes (ESP)/ESL programs and courses. This paper explores the barriers to success, focusing on the sociolinguistic factors of verbal and…

Clinical expectations: what facilitators expect from ESL students on clinical placement.

Science.gov (United States)

San Miguel, Caroline; Rogan, Fran

2012-03-01

Many nursing students for whom English is a second language (ESL) face challenges related to communication on clinical placement and although clinical facilitators are not usually trained language assessors, they are often in a position of needing to assess ESL students' clinical language performance. Little is known, however, about the particular areas of clinical performance facilitators focus on when they are assessing ESL students. This paper discusses the results of a study of facilitators' written assessment comments about the clinical performance of a small group of ESL nursing students over a two and a half year period. These comments were documented on students' clinical assessment forms at the end of each placement. The results provide a more detailed insight into facilitators' expectations of students' language performance and the particular challenges faced by ESL students and indicate that facilitators have clear expectations of ESL students regarding communication, learning styles and professional demeanour. These findings may help both ESL students and their facilitators better prepare for clinical placement. Copyright © 2011 Elsevier Ltd. All rights reserved.

Reflective practice in ESL teacher development groups from practices to principles

CERN Document Server

Farrell, T

2013-01-01

Reflective Practise in ESL Teacher Development Groups  discusses the concept of reflective practice in ESL teachers using data from a 3-year collaborative partnership in which three ESL teachers in Canada explored their professional development through reflective practice.

Lifetime enhanced phosphorescent organic light emitting diode using an electron scavenger layer

Energy Technology Data Exchange (ETDEWEB)

Hong, Seokhwan; Kim, Ji Whan; Lee, Sangyeob, E-mail: sy96.lee@samsung.com [Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, Gyeonggi 443-803 (Korea, Republic of)

2015-07-27

We demonstrate a method to improve lifetime of a phosphorescent organic light emitting diode (OLED) using an electron scavenger layer (ESL) in a hole transporting layer (HTL) of the device. We use a bis(1-(phenyl)isoquinoline)iridium(III)acetylacetonate [Ir(piq){sub 2}(acac)] doped HTL to stimulate radiative decay, preventing thermal degradation in HTL. The ESL effectively prevented non-radiative decay of leakage electron in HTL by converting non-radiative decay to radiative decay via a phosphorescent red emitter, Ir(piq){sub 2}(acac). The lifetime of device (t{sub 95}: time after 5% decrease of luminance) has been increased from 75 h to 120 h by using the ESL in a phosphorescent green-emitting OLED.

Guide to Resources for ESL Literacy Facilitators.

Science.gov (United States)

Gaber-Katz, Elaine; Zettel, Kathryn

This resource guide, for English-as-a-Second-Language (ESL) literacy facilitators, reviews a variety of resources for ESL literacy. The guide contains three sections. The first section cites four books that provide a theoretical context for literacy work: "Ah-Hah! A New Approach to Popular Education" (Gatt-Fly); "Approaches and Methods in Language…

Contextualized Workforce Skills and ESL Learner Identity

Science.gov (United States)

Vafai, Maliheh Mansuripur

2016-01-01

This article reports on an empirical case study centering on adult ESL learners' motivational patterns for learning English and its relevance to their career goals. It looks at past patterns of immigrant insertion within the socioeconomic context of the US and explores current trends in adult ESL curriculum development focused on the task of…

Strangers and Professionals: Positioning Discourse in ESL Teachers' Work

Science.gov (United States)

Haneda, Mari; Nespor, Jan

2013-01-01

English Language Learners (ELLs) usually spend most of the school day with regular classroom teachers. The ability of English-as-a-second-language (ESL) teachers to help these students, then, depends in part on their ability to influence how the classroom teachers think of ELL students and ESL itself. One way ESL teachers do this is through…

ESL Placement and Schools: Effects on Immigrant Achievement.

Science.gov (United States)

Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra; Frisco, Michelle

2009-05-01

In this study, the authors explore English as a Second Language (ESL) placement as a measure of how schools label and process immigrant students. Using propensity score matching and data from the Adolescent Health and Academic Achievement Study and the National Longitudinal Study of Adolescent Health, the authors estimate the effect of ESL placement on immigrant achievement. In schools with more immigrant students, the authors find that ESL placement results in higher levels of academic performance; in schools with few immigrant students, the effect reverses. This is not to suggest a one-size-fits-all policy; many immigrant students, regardless of school composition, generational status, or ESL placement, struggle to achieve at levels sufficient for acceptance to a 4-year university. This study offers several factors to be taken into consideration as schools develop policies and practices to provide immigrant students opportunities to learn.

28 CFR 544.41 - Applicability: Who must attend the ESL program.

Science.gov (United States)

2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Applicability: Who must attend the ESL... INSTITUTIONAL MANAGEMENT EDUCATION Mandatory English-as-a-Second Language Program (ESL) § 544.41 Applicability: Who must attend the ESL program. (a) All Federal prisoners who have limited English proficiency skills...

Willing Learners yet Unwilling Speakers in ESL Classrooms

Directory of Open Access Journals (Sweden)

Zuraidah Ali

2007-12-01

Full Text Available To some of us, speech production in ESL has become so natural and integral that we seem to take it for granted. We often do not even remember how we struggled through the initial process of mastering English. Unfortunately, to students who are still learning English, they seem to face myriad problems that make them appear unwilling or reluctant ESL speakers. This study will investigate this phenomenon which is very common in the ESL classroom. Setting its background on related research findings on this matter, a qualitative study was conducted among foreign students enrolled in the Intensive English Programme (IEP at Institute of Liberal Studies (IKAL, University Tenaga Nasional (UNITEN. The results will show and discuss an extent of truth behind this perplexing phenomenon: willing learners, yet unwilling speakers of ESL, in our effort to provide supportive learning cultures in second language acquisition (SLA to this group of students.

Teachers' Assessment of ESL Students in Mainstream Classes: Challenges, Strategies, and Decision-Making

Science.gov (United States)

Cheng, Liying; Milnes, Terry

2008-01-01

Given the increasing numbers of ESL students in Canadian classrooms, this study investigated how teachers of mainstream classes assess the written work of ESL students and whether they use different assessment strategies for ESL versus non-ESL students. Interviews were conducted with seven mainstream teachers from a private high school in Ontario.…

Translation in ESL Classes

Directory of Open Access Journals (Sweden)

Nagy Imola Katalin

2015-12-01

Full Text Available The problem of translation in foreign language classes cannot be dealt with unless we attempt to make an overview of what translation meant for language teaching in different periods of language pedagogy. From the translation-oriented grammar-translation method through the complete ban on translation and mother tongue during the times of the audio-lingual approaches, we have come today to reconsider the role and status of translation in ESL classes. This article attempts to advocate for translation as a useful ESL class activity, which can completely fulfil the requirements of communicativeness. We also attempt to identify some activities and games, which rely on translation in some books published in the 1990s and the 2000s.

ESL Learners' Online Research and Comprehension Strategies

Science.gov (United States)

Sain, Noridah; Bown, Andy; Fluck, Andrew; Kebble, Paul

2017-01-01

In order to enhance second language (L2) acquisition, English as a Second Language (ESL) students are encouraged to exploit the abundant information and opportunities for authentic language use afforded by the Internet. This study investigated the online research and comprehension strategies employed by ESL learners in a public university in…

Rethinking ESL Service Courses for International Graduate Students

Science.gov (United States)

Min, Young-Kyung

2016-01-01

Drawing on data from a writing program in English as a second language (ESL) at a large university in the midwestern United States, this article addresses the significant gap in programmatic and pedagogical responses for graduate writing support by probing the notion of ESL service courses that approach graduate writing courses as being…

Lexical Borrowings in the ESL Classrooms in Malaysia

Science.gov (United States)

Thirusanku, Jantmary; Yunus, Melor Md

2013-01-01

This paper attempts to show the use of lexical borrowings in ten teaching materials used by the English as Second Language (ESL) teachers in the ESL classrooms in the National Secondary Schools in the Klang district in Selangor, Malaysia. It also discusses the general and pedagogical implications involved in using lexical borrowings. This paper…

Training Using Technology in the Adult ESL Classroom

Science.gov (United States)

McClanahan, Lorna

2014-01-01

In this article I discuss two reasons for the slow adoption of technology as an instructional tool in adult English as a Second Language (ESL) education. I outline recent facts about the relationships between today's adult ESL learners and technology, and then construct a background of theoretical support in favor of integrating technology in…

Balancing Act: Addressing Culture and Gender in ESL Classrooms

Science.gov (United States)

Johnson, Michelle A.; Chang, Debbie

2012-01-01

ESL educators find themselves teaching a diverse group of students in today's classroom. This study investigated how ESL instructors address diversity in their teaching. The literature review revealed research on the experiences of teachers using culturally responsive teaching strategies. Using qualitative research methods, this study explores the…

A Rural South African Experience of an ESL Computer Program

Directory of Open Access Journals (Sweden)

Marius Dieperink

2008-12-01

Full Text Available This article reports on a case study that explored the effect of an English-as-Second Language (ESL computer program at Tshwane University of Technology (TUT, South Africa. The case study explored participants’ perceptions, attitudes and beliefs regarding the ESL reading enhancement program, Reading Excellence™. The study found that participants experienced the program in a positive light. They experienced improved ESL reading as well as listening and writing proficiency. In addition, they experienced improved affective well-being in the sense that they generally felt more comfortable using ESL. This included feeling more self-confident in their experience of their academic environment. Interviews as well as document review resulted in dissonance, however: data pointed towards poor class attendance as well as a perturbing lack of progress in terms of reading comprehension and speed.

Complex Text in ESL Grammar Textbooks: Barriers or Gateways?

Science.gov (United States)

Lesikin, Joan

2000-01-01

Suggests that English-as-a-Second-Language (ESL) teachers assess prospective textbooks by comparing real-life user's actual knowledge of the author's assumed student knowledge. Through examination of charts and page excerpts of two ESL grammar textbooks, demonstrates that access to the pedagogical knowledge demands sophisticated formal knowledge,…

Translating Information Literacy: Online Library Support for ESL Students

Science.gov (United States)

Lombard, Emmett

2016-01-01

This article describes information literacy struggles of ESL college students within the context of four information literacy components: Identify, Locate, Evaluate, Use. Experiences from an online freshman composition course are used to illustrate these struggles, along with techniques academic librarians use to help ESL students from a distance.

Ethical Issues in Addressing Inequity in/through ESL Research

Science.gov (United States)

Lee, Ena

2011-01-01

This article outlines a researcher's struggles with conducting "ethical" research when her case study reveals racializations faced by a minority teacher in a Canadian ESL program. How might becoming privy to research participants' experiences of inequity in ESL education complicate the notion of research ethics when "doing the right…

Literature review: issues surrounding education of English-as-a-Second Language (ESL) nursing students.

Science.gov (United States)

Choi, Liza Lai Shan

2005-07-01

Examined in this article are the challenges faced by English-as-a-Second Language (ESL) nursing students. Nursing faculties need to address these challenges to meet the increasing diversity of the health care system. A key concern is the ability of ESL nursing students to communicate effectively in English. The Cummins model for English language acquisition provides a template for ESL nursing students to bridge this communication barrier. The literature suggests some particular needs of ESL nursing students can be met through modification of nursing programs. Further research into factors affecting the quality of nursing education for ESL students is warranted. A quantitative analysis is required to see if there exists a positive correlation between improved English language acquisition and academic success by ESL nursing students.

Announcing the ESL-WOW for Self-Directed Writing Support

Directory of Open Access Journals (Sweden)

Thaddeus M. Niles

2013-03-01

Full Text Available This is an overview of ESL-WOW (Writing Online Workshop, a new online resource for students aiming to develop academic writing skills which has been available to the public at no charge since December 2012. Students can visit www.esl-wow.org to learn more about the academic conventions that confound new entrants into academic discourse communities, or to learn more about what makes writing clear and cogent in general. While the site is designed for adult learners and students entering community colleges, a wide variety of intermediate and advanced learners can certainly benefit from the materials offered by the ESL-WOW.

Evaluation of a hepatitis B educational ESL curriculum for Chinese immigrants.

Science.gov (United States)

Taylor, Victoria M; Teh, Chong; Lam, Wendy; Acorda, Elizabeth; Li, Lin; Coronado, Gloria; Yasui, Yutaka; Bajdik, Christopher; Hislop, Gregory

2009-01-01

According to recent census data, 1,216,600 Canadians are of Chinese descent, and over 80% of Chinese Canadians are foreign born. Approximately 10% of Chinese immigrants are chronic carriers of hepatitis B, compared with less than 0.5% of the general population. English as a second language (ESL) classes provide ready access for individuals with limited English proficiency who are not reached by English language health education materials and media campaigns. We conducted a group-randomized trial to evaluate the effectiveness of a hepatitis B ESL educational curriculum for Chinese immigrants. Five community-based organizations that provide ESL education in the greater Vancouver area participated in the study. Forty-one ESL classes (which included 325 Chinese students) were randomly assigned to experimental or control status. A follow-up survey, conducted six months after randomization, assessed knowledge about hepatitis B. Generalized estimating equations were used to analyze the data. Follow-up surveys were completed by 298 (92%) of the students. At follow-up, experimental group students were significantly (p ESL curricula can have a positive impact on health knowledge among Chinese immigrants with limited English. Future research should evaluate the effectiveness of ESL curricula for other immigrant groups, as well as other health topics.

Hepatitis B ESL education for Asian immigrants.

Science.gov (United States)

Taylor, Vicky M; Gregory Hislop, T; Bajdik, Christopher; Teh, Chong; Lam, Wendy; Acorda, Elizabeth; Li, Lin; Yasui, Yutaka

2011-02-01

Asian communities in North America include large numbers of immigrants with limited English proficiency. Hepatitis B virus (HBV) infection is endemic in most Asian countries and, therefore, Asian immigrant groups have high rates of chronic HBV infection. We conducted a group-randomized trial to evaluate the effectiveness of a hepatitis B English as a second language (ESL) educational curriculum for Asian immigrants. Eighty ESL classes were randomized to experimental (hepatitis B education) or control (physical activity education) status. Students who reported they had not received a HBV test (at baseline) completed a follow-up survey 6 months after randomization. The follow-up survey assessed recent HBV testing and HBV-related knowledge. Provider reports were used to verify self-reported HBV tests. The study group included 218 students who reported they had not been tested for HBV. Follow-up surveys were completed by 180 (83%) of these students. Provider records verified HBV testing for 6% of the experimental group students and 0% of the control group students (P = 0.02). Experimental group students were significantly (P ESL curriculum had a meaningful impact on HBV-related knowledge and a limited impact on HBV testing levels. Future research should evaluate the effectiveness of ESL curricula for other immigrant groups and other health topics, as well as other intervention approaches to increasing levels of HBV testing in Asian immigrant communities.

Learner's Learning Experiences & Difficulties towards (ESL) among UKM Undergraduates

Science.gov (United States)

Maarof, Nooreiny; Munusamy, Indira Malani A/P

2015-01-01

This paper aims to investigate the learners learning experiences and difficulties of ESL among the UKM undergraduates. This study will be focusing on identifying the factors behind Malaysian undergraduate's experiences and also their difficulties in the English as Second Language (ESL) classroom. This paper discusses some of the issues of English…

Let's Talk! ESL Students' Needs and Writing Centre Philosophy

Science.gov (United States)

Moussu, Lucie

2013-01-01

When university/college faculty members believe that ESL students' writing skills are not equivalent to those of native speakers, they frequently send these ESL students to their institution's writing centres (WCs). However, this often results in frustration for WC staff, the students, and faculty members. This article first describes ESL…

ESL Instruction and Adults with Learning Disabilities. ERIC Digest.

Science.gov (United States)

Schwarz, Robin; Terrill, Lynda

This digest reviews what is known about adult English-as-a-Second-Language (ESL) learners and learning disabilities, suggests ways to identify and assess ESL adults who may have learning disabilities, and offers practical methods for both instruction and teacher training. Topics covered in some detail include identifying and diagnosing learning…

ESL students learning biology: The role of language and social interactions

Science.gov (United States)

Jaipal, Kamini

This study explored three aspects related to ESL students in a mainstream grade 11 biology classroom: (1) the nature of students' participation in classroom activities, (2) the factors that enhanced or constrained ESL students' engagement in social interactions, and (3) the role of language in the learning of science. Ten ESL students were observed over an eight-month period in this biology classroom. Data were collected using qualitative research methods such as participant observation, audio-recordings of lessons, field notes, semi-structured interviews, short lesson recall interviews and students' written work. The study was framed within sociocultural perspectives, particularly the social constructivist perspectives of Vygotsky (1962, 1978) and Wertsch (1991). Data were analysed with respect to the three research aspects. Firstly, the findings showed that ESL students' preferred and exhibited a variety of participation practices that ranged from personal-individual to socio-interactive in nature. Both personal-individual and socio-interactive practices appeared to support science and language learning. Secondly, the findings indicated that ESL students' engagement in classroom social interactions was most likely influenced by the complex interactions between a number of competing factors at the individual, interpersonal and community/cultural levels (Rogoff, Radziszewska, & Masiello, 1995). In this study, six factors that appeared to enhance or constrain ESL students' engagement in classroom social interactions were identified. These factors were socio-cultural factors, prior classroom practice, teaching practices, affective factors, English language proficiency, and participation in the research project. Thirdly, the findings indicated that language played a significant mediational role in ESL students' learning of science. The data revealed that the learning of science terms and concepts can be explained by a functional model of language that includes: (1

Neighbourhood ethnic diversity buffers school readiness impact in ESL children.

Science.gov (United States)

Puchala, Chassidy; Vu, Lan T H; Muhajarine, Nazeem

2010-01-01

Contextual factors, as measured by neighbourhood characteristics, shape the experiences children have and affect their "school readiness", i.e., whether they are well or poorly prepared for the transition from home to kindergarten. This study assessed the independent effects of individual and neighbourhood factors on school readiness; specifically, it examined whether and to what degree neighbourhood factors modified children's language ability and thus their school readiness in a population of children in Saskatoon, Saskatchewan. The study included all children attending kindergarten in 2001, 2003 and 2005 in Saskatoon. School readiness and child characteristics were measured by the Early Development Instrument (EDI). The EDI measures child development at school commencement in five domains: physical health and well-being, social competence, emotional maturity, cognitive and language development, and communication skills and general knowledge. Data from the 2001 Census were used to characterize Saskatoon's neighbourhoods. Multilevel modeling examined the independent and buffering or exacerbating effects of individual and neighbourhood factors on the relation between English as a Second Language (ESL) status in children and EDI domain scores. ESL children had significantly lower scores on all EDI domains compared with non-ESL children. Certain factors (e.g., younger age, male, Aboriginal status, having special needs) were significantly related to lower readiness in terms of the emotional maturity, and communication skills and general knowledge domains. Importantly, children who lived in neighbourhoods that were highly transient (with a higher proportion of residents who had moved in the previous year) had lower EDI scores on both domains, and those in neighbourhoods with lower rates of employment had lower EDI scores on communication skills and general knowledge. Neighbourhood ethnic diversity mitigated the negative impact of ESL status on school readiness for both

Development of an ESL curriculum to educate Chinese immigrants about hepatitis B.

Science.gov (United States)

Taylor, Victoria M; Coronado, Gloria; Acorda, Elizabeth; Teh, Chong; Tu, Shin-Ping; Yasui, Yutaka; Bastani, Roshan; Hislop, T Gregory

2008-08-01

Chinese immigrants to North America have substantially higher rates of chronic hepatitis B infection than the general population. One area for strategic development in the field of health education is the design and evaluation of English-as-a-Second language (ESL) curricula. The theoretical perspective of the Health Behavior Framework, results from a community-based survey of Chinese Canadian immigrants with limited English proficiency, and findings from focus groups of ESL instructors as well as Chinese ESL students were used to develop a hepatitis B ESL educational module. This research was conducted in Vancouver, BC. Survey data showed that less than three-fifths of the respondents had been tested for hepatitis B, and documented some important hepatitis B knowledge deficits. Further, only about one-quarter had ever received a physician recommendation for hepatitis B serologic testing. The ESL curriculum aims to both promote hepatitis B testing and improve knowledge, and includes seven different ESL exercises: Warm-up, vocabulary cards, information-gap, video, jigsaw, guided discussion, and problem/advice cards. Our quantitative and qualitative methods for curriculum development could be replicated for other health education topics and in other limited English speaking populations.

Blood pressure-lowering effects of sulodexide depend on albuminuria severity: post hoc analysis of the sulodexide microalbuminuria and macroalbuminuria studies

NARCIS (Netherlands)

Olde Engberink, Rik H. G.; Heerspink, Hiddo J. L.; de Zeeuw, Dick; Vogt, Liffert

2016-01-01

It has been suggested that sulodexide is able to lower blood pressure (BP). This may be attributed to its ability to restore the endothelial surface layer (ESL). As ESL perturbation is known to be related to the degree of kidney damage, we investigated whether albuminuria, reflecting ESL status,

Blood pressure-lowering effects of sulodexide depend on albuminuria severity : post hoc analysis of the sulodexide microalbuminuria and macroalbuminuria studies

NARCIS (Netherlands)

Engberink, Rik H. G. Olde; Heerspink, Hiddo J. L.; de Zeeuw, Dick; Vogt, Liffert

AIMS: It has been suggested that sulodexide is able to lower blood pressure (BP). This may be attributed to its ability to restore the endothelial surface layer (ESL). As ESL perturbation is known to be related to the degree of kidney damage, we investigated whether albuminuria, reflecting ESL

Grammar and Teaching ESL

Science.gov (United States)

Morrissey, Glenda; Young, Barbara N.

2005-01-01

The variety of theories relating to teaching ESL learners leads to contradictory ideas about teaching a second language. This paper focuses on the continuing importance of grammar in teaching and the current resurgence in interest in returning to grammar as an important component in the classroom.

Organic light emitting diode with surface modification layer

Science.gov (United States)

Basil, John D.; Bhandari, Abhinav; Buhay, Harry; Arbab, Mehran; Marietti, Gary J.

2017-09-12

An organic light emitting diode (10) includes a substrate (12) having a first surface (14) and a second surface (16), a first electrode (32), and a second electrode (38). An emissive layer (36) is located between the first electrode (32) and the second electrode (38). The organic light emitting diode (10) further includes a surface modification layer (18). The surface modification layer (18) includes a non-planar surface (30, 52).

Flipped ESL Teacher Professional Development: Embracing Change to Remain Relevant

Science.gov (United States)

Razak, Rafiza Abdul; Kaur, Dalwinder; Halili, Siti Hajar; Ramlan, Zahri

2016-01-01

Many traditional professional development programs that are initiated to equip ESL teachers with knowledge and skills have been futile for numerous reasons. This paper addresses a gap in the recent research of ESL teachers' professional development. Literature has revealed many shortcomings of the traditional and online professional development…

Could laser-assisted dissection of the pre-epiglottic space affect functional outcome after ESL?

Science.gov (United States)

Bertolin, Andy; Lionello, Marco; Russo, Simone; Rizzotto, Giuseppe; Lucioni, Marco

2018-06-01

To evaluate the effect of preepiglottic space (PES) dissection in the endoscopic supraglottic laryngectomy (ESL). A retrospective cohort study. We retrospectively compared 15 patients who underwent ESL with 15 patients matched for clinical stage who underwent open partial horizontal laryngectomy (OPHL). The functional outcomes were assessed in terms of hospital stay; need for nasal feeding tube (NFT) and tracheostomy, as well as duration of their use; postoperative complications; aspiration pneumonia rates; voice quality; and dysphagia. Among the ESL cases, combined dissection of the epiglottis and PES (type III) had a negative impact on functional outcomes. ESL patients experienced shorter hospital stays, as well as shorter use of NFT and tracheostomy, than patients who had OPHL. Combined dissection of the epiglottis and PES (ESL type III) negatively affected functional outcome in patients undergoing ESL, a procedure generally related to significantly better functional outcomes than OPHL type I. 4. Laryngoscope, 128:1371-1378, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Accent, Identity, and a Fear of Loss? ESL Students' Perspectives

Science.gov (United States)

McCrocklin, Shannon; Link, Stephanie

2016-01-01

Because many theorists propose a connection between accent and identity, some theorists have justifiably been concerned about the ethical ramifications of L2 pronunciation teaching. However, English-as-a-second-language (ESL) students often state a desire to sound like native speakers. With little research into ESL students' perceptions of links…

English-as-a-Second Language (ESL) nursing student success: a critical review of the literature.

Science.gov (United States)

Olson, Mary Angela

2012-01-01

Many English-as-a-Second Language (ESL) nursing students struggle in nursing school for a multitude of reasons. The purpose of this critical review of the literature is to identify barriers and discover bridges to ESL nursing student success. Twenty-five articles were identified for the review. Language barriers were identified as the single most significant obstacle facing the ESL nursing student. Bridges to ESL nursing student success include enhancing language development and acculturation into the American mainstream culture. A broad range of strategies to promote student success are outlined and the role of the nurse educator in ESL nursing student success is also addressed.

Factors Inhibiting ESL Learners from Passing California High School Exit Examination: A Narrative Inquiry

Science.gov (United States)

Puente, Belinda

2017-01-01

The problem was that Hispanic English Second Language (ESL) students enrolled in the ESL program had consistently failed the California High School Exit Examination (CASHEE) in greater numbers than their cohorts. The purpose of this qualitative narrative inquiry was to explore the life stories of Hispanic ESL students in identifying the factors…

Comments on Elsa Roberts Auerbach's "Reexamining English Only in the ESL Classroom."

Science.gov (United States)

Polio, Charlene; Auerbach, Elsa Roberts

1994-01-01

Arguments for students' use of their first language as well as English in the English-as-a-Second-Language (ESL) classroom are reexamined. Pedagogical and political aspects of ESL instruction are noted. (LB)

Surface layer effects on waste glass corrosion

International Nuclear Information System (INIS)

Feng, X.

1993-01-01

Water contact subjects waste glass to chemical attack that results in the formation of surface alteration layers. Two principal hypotheses have been advanced concerning the effect of surface alteration layers on continued glass corrosion: (1) they act as a mass transport barrier and (2) they influence the chemical affinity of the glass reaction. In general, transport barrier effects have been found to be less important than affinity effects in the corrosion of most high-level nuclear waste glasses. However, they can be important under some circumstances, for example, in a very alkaline solution, in leachants containing Mg ions, or under conditions where the matrix dissolution rate is very low. The latter suggests that physical barrier effect may affect the long-term glass dissolution rate. Surface layers influence glass reaction affinity through the effects of the altered glass and secondary phases on the solution chemistry. The reaction affinity may be controlled by various precipitates and crystalline phases, amorphous silica phases, gel layer, or all the components of the glass. The surface alteration layers influence radionuclide release mainly through colloid formation, crystalline phase incorporation, and gel layer retention. This paper reviews current understanding and uncertainties

Empirical Study on Learners' Self-Efficacy in ESL/EFL Context

Science.gov (United States)

Shi, Lihong

2016-01-01

With the popularity of learner-oriented approach in language teaching, research on learners is gaining more and more importance. This paper attempts to review the empirical researches on self-efficacy in the ESL/EFL settings during the past 10 years with the purpose of depicting the extent to which the self-efficacy research in ESL/EFL has…

Smartphones Promote Autonomous Learning in ESL Classrooms

Directory of Open Access Journals (Sweden)

Viji Ramamuruthy

2015-10-01

Full Text Available The rapid development of high-technology has caused new inventions of gadgets for all walks of life regardless age. In this rapidly advancing technology era many individuals possess hi-tech gadgets such as laptops, tablets, iPad, android phones and smart phones. Adult learners in higher learning institution especially are fond of using smart phones. Students become passive in the classrooms as they are glued to their smart phones. This situation triggers the question of whether learning really takes place while the students are too engaged with their smart phones in the ESL classroom. In this context, the following questions are framed to investigate this issue: What type of learning skills are gained by using smartphones in ESL classrooms? Does smartphone use promote the autonomous learning process? To what extent do learners rely on the lecturers in addition to the usage of smartphones? What are the learning satisfactions gained by ESL learners using smartphones? A total of 70 smartphone users in the age range 18 to 26 years participated in this quantitative study. Questionnaires eliciting demographic details of the respondents, learning skills, learning satisfaction, students' perception on teacher's role in the ESL classroom and autonomous learning were distributed to all the randomly chosen samples. The data were then analyzed by using SPSS version 16. The findings revealed that smartphone use boosted learners’ critical thinking, creative thinking, communication and collaboration skills. In fact, learners gain great satisfaction in the learning process through smartphones. Although learners have moved toward autonomous learning, they are still reliant on the teachers to achieve their learning goals.

Laser modification of macroscopic properties of metal surface layer

Science.gov (United States)

Kostrubiec, Franciszek

1995-03-01

Surface laser treatment of metals comprises a number of diversified technological operations out of which the following can be considered the most common: oxidation and rendering surfaces amorphous, surface hardening of steel, modification of selected physical properties of metal surface layers. In the paper basic results of laser treatment of a group of metals used as base materials for electric contacts have been presented. The aim of the study was to test the usability of laser treatment from the viewpoint of requirements imposed on materials for electric contacts. The results presented in the paper refer to two different surface treatment technologies: (1) modification of infusible metal surface layer: tungsten and molybdenum through laser fusing of their surface layer and its crystallization, and (2) modification of surface layer properties of other metals through laser doping of their surface layer with foreign elements. In the paper a number of results of experimental investigations obtained by the team under the author's supervision are presented.

The Short Circuit Hypothesis of ESL Reading--Or when Language Competence Interferes with Reading Performance.

Science.gov (United States)

Clarke, Mark A.

1980-01-01

Examines a sampling of current ESL reading instruction practices, addressing the concern that the lack of a generally accepted theory of L2 reading constitutes a major obstacle to teaching and testing ESL reading skills. Summarizes the results of two studies and discusses their implications for ESL teachers. (MES)

The surface roughness and planetary boundary layer

Science.gov (United States)

Telford, James W.

1980-03-01

Applications of the entrainment process to layers at the boundary, which meet the self similarity requirements of the logarithmic profile, have been studied. By accepting that turbulence has dominating scales related in scale length to the height above the surface, a layer structure is postulated wherein exchange is rapid enough to keep the layers internally uniform. The diffusion rate is then controlled by entrainment between layers. It has been shown that theoretical relationships derived on the basis of using a single layer of this type give quantitatively correct factors relating the turbulence, wind and shear stress for very rough surface conditions. For less rough surfaces, the surface boundary layer can be divided into several layers interacting by entrainment across each interface. This analysis leads to the following quantitatively correct formula compared to published measurements. 1 24_2004_Article_BF00877766_TeX2GIFE1.gif {σ _w }/{u^* } = ( {2/{9Aa}} )^{{1/4}} ( {1 - 3^{{1/2}{ a/k{d_n }/z{σ _w }/{u^* }z/L} )^{{1/4}} = 1.28(1 - 0.945({{σ _w }/{u^* }}}) {{z/L}})^{{1/4 where u^* = ( {{tau/ρ}}^{{1/2}}, σ w is the standard deviation of the vertical velocity, z is the height and L is the Obukhov scale lenght. The constants a, A, k and d n are the entrainment constant, the turbulence decay constant, Von Karman's constant, and the layer depth derived from the theory. Of these, a and A, are universal constants and not empirically determined for the boundary layer. Thus the turbulence needed for the plume model of convection, which resides above these layers and reaches to the inversion, is determined by the shear stress and the heat flux in the surface layers. This model applies to convection in cool air over a warm sea. The whole field is now determined except for the temperature of the air relative to the water, and the wind, which need a further parameter describing sea surface roughness. As a first stop to describing a surface where roughness elements

Career Development and Professional Attrition of Novice ESL Teachers of Adults

Science.gov (United States)

Valeo, Antonella; Faez. Farahnaz

2013-01-01

Research and development in language teacher education and, more recently, teacher accreditation has had enormous impact on the professional lives of ESL teachers in Canada. There has been less interest, however, in examining the career development and employment experiences of accredited ESL teachers as they transition from TESL programs to ESL…

Exploring Scintillometry in the Stable Atmospheric Surface Layer

NARCIS (Netherlands)

Hartogensis, O.K.

2006-01-01

The main objective of this thesis is to investigate observation methods of heat and momentum exchange and key variables that characterise turbulence in the atmospheric stable surface layer (SSL), a layer defined as the lower part of the stable boundary layer (SBL) where surface fluxes do not change

Challenges of recruiting ESL immigrants into cancer education studies: reflections from practice notes.

Science.gov (United States)

Thomson, Maria D; Hoffman-Goetz, Laurie

2011-03-01

Changing population demographics and immigration patterns have resulted in increasing numbers of Canadians who report speaking a language other than French or English. Inclusion of English-as-a-second-language (ESL) immigrants in cancer education research is critical if disparities in access and use of preventive health care services are to be addressed. This article describes the challenges experienced recruiting and interviewing older ESL immigrant women for a colon cancer prevention study. Factors influencing the recruitment and interview of ESL immigrant women were identified through regular team meetings, interviews, and reflective practice notes. Issues included the importance of community contacts, language barriers, and the motivations of the women for participating. Recommendations for recruitment and inclusion of ESL immigrants in cancer education research are provided.

Learner’s Learning Experiences & Difficulties towards (ESL among UKM Undergraduates

Directory of Open Access Journals (Sweden)

Nooreiny Maarof

2015-06-01

Full Text Available This paper aims to investigate the learners learning experiences and difficulties of ESL among the UKM undergraduates. This study will be focusing on identifying the factors behind Malaysian undergraduate’s experiences and also their difficulties in the English as Second Language (ESL classroom. This paper discusses some of the issues of English language learning experiences at the tertiary level in this country. It reflects on how the teaching of English is variously conceptualized in our classrooms, raising important questions about the positions of English literacy to Malaysian undergraduates. A qualitative research method was employed, whereby a semi-structured interview session was conducted compromising thirty Bachelor of Arts undergraduates (BA ELS. The findings of this study suggests learners at tertiary  level do face challenges in their ESL classroom learning,  in areas such as the learning environment itself needs to be improved, the quality of education, the academics, the role of educators and the teaching approach were among others pointed out by the learners themselves.  Keywords: English language teaching, English as Second language (ESL, learner’s experiences, learner’s difficulties, language learners

Change of Surface Roughness and Planetary Boundary Layer

DEFF Research Database (Denmark)

Jensen, Niels Otto

1978-01-01

The ratio between upstream and far downstream surface friction velocities relative to a change in surface roughness is given on the basis of results from surface Rossby number similarity theory. By simple theories for the internal boundary layer, which are found to compare quite well with recent...... numerical results from higher-order closure models, it is found that, even at a downwind distance such that the internal boundary layer has grown to the full height of the planetary boundary layers, the surface stress still considerably exceeds the equilibrium value...

Optimizing an immersion ESL curriculum using analytic hierarchy process.

Science.gov (United States)

Tang, Hui-Wen Vivian

2011-11-01

The main purpose of this study is to fill a substantial knowledge gap regarding reaching a uniform group decision in English curriculum design and planning. A comprehensive content-based course criterion model extracted from existing literature and expert opinions was developed. Analytical hierarchy process (AHP) was used to identify the relative importance of course criteria for the purpose of tailoring an optimal one-week immersion English as a second language (ESL) curriculum for elementary school students in a suburban county of Taiwan. The hierarchy model and AHP analysis utilized in the present study will be useful for resolving several important multi-criteria decision-making issues in planning and evaluating ESL programs. This study also offers valuable insights and provides a basis for further research in customizing ESL curriculum models for different student populations with distinct learning needs, goals, and socioeconomic backgrounds. Copyright © 2011 Elsevier Ltd. All rights reserved.

In-situ surface hardening of cast iron by surface layer metallurgy

International Nuclear Information System (INIS)

Fischer, Sebastian F.; Muschna, Stefan; Bührig-Polaczek, Andreas; Bünck, Matthias

2014-01-01

Abrasive wear is a serious problem in many cast iron castings used in industry. To minimize failure and repair of these components, different strategies exist to improve their surface microhardness thus enhancing their wear resistance. However, most of these methods lead to very brittle and/or expensive castings. In the current work a new method for surface hardening is presented which utilizes surface layer metallurgy to generate in-situ a boron-enriched white cast iron surface layer with a high microhardness on a gray cast iron casting. To do this, sand molds are coated with a ferroboron suspension and cast with a cast iron melt. After solidification, a 100–900 µm thick layer of boron-enriched ledeburite is formed on the surface of the casting which produces an increase in the average microhardness from 284 HV 0.1 ±52 HV 0.1 to 505 HV 0.1 ±87 HV 0.1 . Analyses of the samples' core reveal a typical cast iron microstructure which leads to the conclusion that the coating mainly affects the castings' surface. By varying the grain size of the ferroboron powder in the coatings, it is shown that a powder size ≤100 µm is most suitable to create a boron-enriched ledeburite surface layer possessing high hardness values

Perceptions of school nurses on the challenges of service provision to ESL students.

Science.gov (United States)

Whitman, Marilyn V; Davis, Jullet A; Terry, Allison J

2010-04-01

The number of English-as-as second-language (ESL) students in public schools across the country is rising creating unique challenges for school health services with the introduction of new cultures and languages. This study describes the perceptions of school nurses in Alabama schools regarding the challenges they face when communicating with ESL students and their parents. The population consists of school nurses in Alabama public schools. The obtained sample of 1,429 responses is presented and discussed. Urban school nurses were more likely to have access to an interpreter, yet they were more likely to rely on an ESL student to act as a translator when speaking to his/her parents. Kindergarten through elementary school nurses were more likely to witness an increase in ESL students and encounter difficulty communicating with these students and their parents. School nurses have a unique opportunity to engage parents of ESL students in the health of their child, thus it is vital that they be provided with cultural facts and encouraged to use interpreter services to lessen language barriers.

Tuning In: Using the News for a Content-Based ESL Class

Science.gov (United States)

Moglen, Daniel

2014-01-01

Vast amounts of daily news content are widely available and easily accessible, and they can be converted into materials for intermediate and advanced ESL classes. This article will describe the why and how for integrating news media sources into a multiskills ESL classroom. Through the news, students are immediately engaged with the material…

The Experiences in Processing Policies and Contracts by Adult ESL Readers

Science.gov (United States)

Abiog, Evalyn B.

2017-01-01

The present study describes the experiences of adult English as a Second Language (ESL) readers in processing legal texts prior to entering a financial agreement. A preliminary survey was conducted to determine the commonly read policies and contracts of adult ESL reader-consumers, which revealed those of banks and life-insurance companies; hence,…

E-selectin ligand-1 (ESL-1) is a novel adiponectin binding protein on cell adhesion

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Hiroyasu; Kuroda, Nana; Uekita, Hiromi; Kochi, Ikoi; Matsumoto, Akane; Niinaga, Ryu [Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Osaka (Japan); Funahashi, Tohru; Shimomura, Iichiro [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka (Japan); Kihara, Shinji, E-mail: skihara@sahs.med.osaka-u.ac.jp [Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Osaka (Japan)

2016-02-05

Background: Adiponectin (APN) is an adipocyte-derived bioactive molecule with anti-diabetic and anti-atherogenic properties. Although anti-diabetic effects are mostly mediated by the adiponectin receptors AdipoR1 and AdipoR2, the anti-atherogenic mechanisms have not been fully elucidated. Methods and Results: In this study, we identified E-selectin ligand (ESL)-1 as a novel APN-binding protein by mass spectrometry analysis of HepG2 cell-derived immunoprecipitant with an anti-APN antibody. Cell adhesion assays using fluorescence-labelled monocyte cell line THP-1 cells and human umbilical vein endothelial cells (HUVECs) revealed that APN-pre-treated THP-1 cells had reduced binding ability to HUVECs. This APN-mediated suppressive effect on monocyte binding to endothelial cells was partially abrogated by targeting ESL-1 with shRNA in THP-1 cells. In addition, serial mutagenesis analysis disclosed that five extracellular amino acids close to the N-terminus of ESL-1 were essential for binding with APN. Conclusion: Our results highlight the fact that interaction between APN and ESL-1 could provide a fundamental mechanism underlying the anti-atherogenic properties of APN. - Highlights: • E-selectin ligand (ESL)-1 was identified as an adiponectin (APN)-binding protein. • ESL-1 bound to APN at its N-terminal 6th-10th amino acids. • shESL-1 reduced the suppressive effect of APN on adhesion of THP-1 cells to HUVECs. • Interaction with ESL may be involved in the anti-atherogenic effects of APN.

E-selectin ligand-1 (ESL-1) is a novel adiponectin binding protein on cell adhesion

International Nuclear Information System (INIS)

Yamamoto, Hiroyasu; Kuroda, Nana; Uekita, Hiromi; Kochi, Ikoi; Matsumoto, Akane; Niinaga, Ryu; Funahashi, Tohru; Shimomura, Iichiro; Kihara, Shinji

2016-01-01

Background: Adiponectin (APN) is an adipocyte-derived bioactive molecule with anti-diabetic and anti-atherogenic properties. Although anti-diabetic effects are mostly mediated by the adiponectin receptors AdipoR1 and AdipoR2, the anti-atherogenic mechanisms have not been fully elucidated. Methods and Results: In this study, we identified E-selectin ligand (ESL)-1 as a novel APN-binding protein by mass spectrometry analysis of HepG2 cell-derived immunoprecipitant with an anti-APN antibody. Cell adhesion assays using fluorescence-labelled monocyte cell line THP-1 cells and human umbilical vein endothelial cells (HUVECs) revealed that APN-pre-treated THP-1 cells had reduced binding ability to HUVECs. This APN-mediated suppressive effect on monocyte binding to endothelial cells was partially abrogated by targeting ESL-1 with shRNA in THP-1 cells. In addition, serial mutagenesis analysis disclosed that five extracellular amino acids close to the N-terminus of ESL-1 were essential for binding with APN. Conclusion: Our results highlight the fact that interaction between APN and ESL-1 could provide a fundamental mechanism underlying the anti-atherogenic properties of APN. - Highlights: • E-selectin ligand (ESL)-1 was identified as an adiponectin (APN)-binding protein. • ESL-1 bound to APN at its N-terminal 6th-10th amino acids. • shESL-1 reduced the suppressive effect of APN on adhesion of THP-1 cells to HUVECs. • Interaction with ESL may be involved in the anti-atherogenic effects of APN.

School Context and the Effect ESL Placement on Mexican-Origin Adolescents' Achievement.

Science.gov (United States)

Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra

2008-01-01

OBJECTIVES: Immigrant adolescents' academic achievement is crucial to our future economic stability, and Mexican-origin linguistic minority youth in U.S. schools generally demonstrate lower levels of achievement. English as a Second Language (ESL) programs provide an institutional response to these students' needs, the effect of which may vary by the proportion of immigrant students in the school. MEASURES: Using propensity score matching and data from the Adolescent Health and Academic Achievement Study (AHAA) and the National Longitudinal Study of Adolescent Health (Add Health), we estimate the effect of ESL placement on Mexican-origin achievement for first-, second-, and third-generation adolescents separately in schools with many and few immigrant students. RESULTS: The estimated effect of ESL placement varies by both immigrant concentration in the school and by students' generational status. CONCLUSIONS: We find that ESL enrollment may be protective for second-generation Mexican-origin adolescents in high immigrant concentration schools, and may prove detrimental for first-generation adolescents in contexts with few other immigrant students.

Effects of surface modification on the critical behaviour in multiple-surface-layer ferroelectric thin films

International Nuclear Information System (INIS)

Lu, Z X

2013-01-01

Using the usual mean-field theory approximation, the critical behaviour (i.e. the Curie temperature T c and the critical surface transverse field Ω sc ) in a multiple-surface-layer ferroelectric thin film is studied on the basis of the spin- 1/2 transverse Ising model. The dependence of the Curie temperature T c on the surface transverse field Ω s and the surface layer number N s are discussed in detail. Meanwhile the dependence of the critical surface transverse field Ω sc on the surface layer number N s is also examined. The numerical results indicate that the critical behaviour of ferroelectric thin films is obviously affected by modifications of the surface transverse field Ω s and surface layer number N s .

Atomic and molecular layer deposition for surface modification

Energy Technology Data Exchange (ETDEWEB)

Vähä-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland); Sievänen, Jenni; Salo, Erkki; Heikkilä, Pirjo; Kenttä, Eija [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland); Johansson, Leena-Sisko, E-mail: leena-sisko.johansson@aalto.fi [Aalto University, School of Chemical Technology, Department of Forest Products Technology, PO Box 16100, FI‐00076 AALTO (Finland); Koskinen, Jorma T.; Harlin, Ali [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland)

2014-06-01

Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces. However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjet printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid. - Graphical abstract: Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. - Highlights: • ALD/MLD can be used to adjust surface characteristics of films and fiber materials. • Hydrophobicity after few deposition cycles of Al{sub 2}O{sub 3} due to e.g. complex formation. • Same effect on cellulosic fabrics observed with low temperature deposited TiO{sub 2}. • Different film growth and oxidation potential with different precursors. • Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt.

The Conflation of Adult ESL and Literacy: The Views of Experienced Teachers

Science.gov (United States)

Fleming, Douglas; René, Carène Pierre; Bangou, Francis; Sarwar, Gul Shahzad

2015-01-01

This article explores the links between English as a second language (ESL) instruction and literacy instruction through an examination of viewpoints from eight teachers in two Canadian provinces. Four of these teachers worked in government--funded adult ESL and literacy education programs for a large urban school district in the province of…

Study on tribological properties of multi-layer surface texture on Babbitt alloys surface

Science.gov (United States)

Zhang, Dongya; Zhao, Feifei; Li, Yan; Li, Pengyang; Zeng, Qunfeng; Dong, Guangneng

2016-12-01

To improve tribological properties of Babbitt alloys, multi-layer surface texture consisted of the main grooves and secondary micro-dimples are fabricated on the Babbitt substrate through laser pulse ablation. The tribological behaviors of multi-layer surface texture are investigated using a rotating type pin-on-disc tribo-meter under variation sliding speeds, and the film pressure distributions on the textured surfaces are simulated using computational fluid dynamics (CFD) method for elucidating the possible mechanisms. The results suggest that: (i) the multi-layer surface texture can reduce friction coefficient of Babbitt alloy, which has lowest friction coefficient of 0.03, in case of the groove parameter of 300 μm width and 15% of area density; (ii) the improvement effect may be more sensitive to the groove area density and the siding speed, and the textured surface with lower area density has lower friction coefficient under high sliding speed. Based on the reasons of (i) the secondary micro-dimples on Babbitt alloy possesses a hydrophobicity surface and (ii) the CFD analysis indicates that main grooves enhancing hydrodynamic effect, thus the multi-layer surface texture is regarded as dramatically improve the lubricating properties of the Babbitt alloy.

Principled Eclecticism: Approach and Application in Teaching Writing to ESL/EFL Students

Science.gov (United States)

Alharbi, Sultan H.

2017-01-01

The principal purpose of this paper is to critically examine and evaluate the efficacy of the principled eclectic approach to teaching English as second/foreign language (ESL/EFL) writing to undergraduate students. The paper illustrates that this new method adapts mainstream writing pedagogies to individual needs of learners of ESL/EFL in order to…

Influence of Speech Anxiety on Oral Communication Skills among ESL/EFL Learners

Science.gov (United States)

Khan, Said Muhammad

2015-01-01

The realization of speech anxiety among ESL/EFL learners is important. Once understood, these feelings of fear or nervousness may be relieved and the desired objectives of learning the target language may be achieved. The study has attempted to measure the level of anxiety among ESL/EFL learners at HITEC University, Taxila, Pakistan. The current…

Using Facebook-Based e-Portfolio in ESL Writing Classrooms: Impact and Challenges

Science.gov (United States)

Barrot, Jessie S.

2016-01-01

In English as a second language (ESL) writing pedagogy, much attention has been given to electronic portfolio (e-portfolio) assessment via social networking sites. However, little is known about how Facebook can be used as an e-portfolio platform. Hence, this paper describes the impact of Facebook-based e-portfolio on ESL students' writing…

Development of an ESL curriculum to educate Chinese immigrants about physical activity.

Science.gov (United States)

Taylor, Victoria M; Cripe, Swee May; Acorda, Elizabeth; Teh, Chong; Coronado, Gloria; Do, Hoai; Woodall, Erica; Hislop, T Gregory

2008-08-01

Regular physical activity reduces the risk of many chronic conditions. Multiple studies have shown that Asians in North America engage in less physical activity than the general population. One area for strategic development in the area of health education is the design and evaluation of English as a second language (ESL) curricula. The PRECEDE model and findings from focus groups were used to develop a physical activity ESL curriculum for Chinese immigrants. In general, focus group participants recognized that physical activity contributes to physical and mental wellbeing. However, the benefits of physical activity were most commonly described in terms of improved blood circulation, immune responses, digestion, and reflexes. The importance of peer pressure and the encouragement of friends in adhering to regular physical activity regimens were mentioned frequently. Reported barriers to regular physical activity included lack of time, weather conditions, and financial costs. The ESL curriculum aims to both promote physical activity and improve knowledge, and includes seven different ESL exercises. Our curriculum development methods could be replicated for other health education topics and in other limited English-speaking populations.

School Context and the Effect ESL Placement on Mexican-Origin Adolescents’ Achievement*

Science.gov (United States)

Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra

2010-01-01

Objectives Immigrant adolescents’ academic achievement is crucial to our future economic stability, and Mexican-origin linguistic minority youth in U.S. schools generally demonstrate lower levels of achievement. English as a Second Language (ESL) programs provide an institutional response to these students’ needs, the effect of which may vary by the proportion of immigrant students in the school. Measures Using propensity score matching and data from the Adolescent Health and Academic Achievement Study (AHAA) and the National Longitudinal Study of Adolescent Health (Add Health), we estimate the effect of ESL placement on Mexican-origin achievement for first-, second-, and third-generation adolescents separately in schools with many and few immigrant students. Results The estimated effect of ESL placement varies by both immigrant concentration in the school and by students’ generational status. Conclusions We find that ESL enrollment may be protective for second-generation Mexican-origin adolescents in high immigrant concentration schools, and may prove detrimental for first-generation adolescents in contexts with few other immigrant students. PMID:20354570

THE PRONUNCIATION COMPONENT IN ESL LESSONS: TEACHERS’ BELIEFS AND PRACTICES

Directory of Open Access Journals (Sweden)

Shanina Sharatol Ahmad Shah

2017-01-01

Full Text Available Research has shown that teachers’ beliefs on teaching and learning exert an influence on their actual classroom practices. In the teaching of English pronunciation, teachers’ beliefs play a crucial role in the choice of pronunciation components taught in the ESL classrooms. This paper explores teachers’ beliefs about teaching English pronunciation in Malaysian classrooms and the extent to which these beliefs influenced the teachers’ classroom instructions. Employing a multiple case study of five ESL teachers in secondary schools, this study investigated the beliefs the teachers have formed about pronunciation focused areas and classroom practices in teaching English pronunciation. Data were collected through actual classroom observations and semi-structured interviews with the teachers and students. The findings of the study found that ESL teachers seem to believe that pronunciation skills are to be taught integratedly with other English language skills. Results also indicate a discrepancy between these teachers’ beliefs on the focused areas of pronunciation and the stated curriculum specifications.  Additionally, the ESL teachers seem to have vague and contradictory beliefs about pronunciation focused areas. These beliefs are based on their previous language learning and professional experience as well as other contextual factors such as examination demands and time constraints. As a result, these beliefs lead to the pronunciation component being neglected despite it being stipulated by the curriculum.

Literature in EFL/ESL Classroom

Science.gov (United States)

Khatib, Mohammad; Rezaei, Saeed; Derakhshan, Ali

2011-01-01

This paper is a review of literature on how literature can be integrated as a language teaching material in EFL/ESL classes. First, it tracks down the place of literature in language classes from the early Grammar Translation Method (GTM) to Communicative Language Teaching (CLT) era. The paper then discusses the reasons for the demise and…

Thermal healing of the sub-surface damage layer in sapphire

International Nuclear Information System (INIS)

Pinkas, Malki; Lotem, Haim; Golan, Yuval; Einav, Yeheskel; Golan, Roxana; Chakotay, Elad; Haim, Avivit; Sinai, Ela; Vaknin, Moshe; Hershkovitz, Yasmin; Horowitz, Atara

2010-01-01

The sub-surface damage layer formed by mechanical polishing of sapphire is known to reduce the mechanical strength of the processed sapphire and to degrade the performance of sapphire based components. Thermal annealing is one of the methods to eliminate the sub-surface damage layer. This study focuses on the mechanism of thermal healing by studying its effect on surface topography of a- and c-plane surfaces, on the residual stresses in surface layers and on the thickness of the sub-surface damage layer. An atomically flat surface was developed on thermally annealed c-plane surfaces while a faceted roof-top topography was formed on a-plane surfaces. The annealing resulted in an improved crystallographic perfection close to the sample surface as was indicated by a noticeable decrease in X-ray rocking curve peak width. Etching experiments and surface roughness measurements using white light interferometry with sub-nanometer resolution on specimens annealed to different extents indicate that the sub-surface damage layer of the optically polished sapphire is less than 3 μm thick and it is totally healed after thermal treatment at 1450 deg. C for 72 h.

Modeling Turbulence Generation in the Atmospheric Surface and Boundary Layers

Science.gov (United States)

2015-10-01

hydrostatic equation: dP dz = −ρa g −→ ∫ ZI 0 ρa dz = − 1 g ∫ dP = + 1 g [P (0)− P (ZI)]. (6.14) The pressure at the surface is... surface pressure is estimated, we can compute a vertical pressure profile using the hydrostatic equation and a selected temperature profile based on dP... surface -layer atmosphere. By surface layer what is intended is a layer of foliage plus the surface itself. That is, a flat ground surface that

Research on Eye Movement Tracking in ESL Reading

Directory of Open Access Journals (Sweden)

Wenlian ZHAN

2014-06-01

Full Text Available Eye movement behavior in reading can reflect on-line cognitive process. Through the on-line measure of eye movement, under relatively natural reading condition, data of the reader’ s eye movement in the text can be obtained in processing information, and thus help to reveal the internal cognitive mechanisms in reading. With the development of intelligentization, serialization and portable direction in eye tracker, there exist great number of studies on eye movement tracking, but studies on eye movement features in ESL reading are rare. In such circumstances, this paper mainly illustrates eye movement patterns, the relationship between eye movement and perceptual processing, and eye movement control in ESL reading.

Perceptions of ESL Program Management in Canadian Higher Education: A Qualitative Case Study

Science.gov (United States)

Eaton, Sarah Elaine

2017-01-01

ESL programs at post-secondary institutions must often generate revenue in addition to teaching students English. Institutions often impose explicit expectations on these programs to generate profit, creating unique challenges for those who administer them. This qualitative case study investigated challenges faced by ESL program directors at one…

A Correlational Study of a Reading Comprehension Program and Attrition Rates of ESL Nursing Students in Texas.

Science.gov (United States)

Donnell, Wendy M

The purpose of this study was to examine the associations between English as a second language (ESL), a reading comprehension program, and attrition rates of nursing students. Higher attrition rates of ESL nursing students are an assumption, seemingly based on anecdotal evidence. Data reflecting ESL student attrition should be measured and analyzed so that students can be identified prior to attrition. A secondary analysis of a large database of 27 initial licensure programs in Texas was completed. Data analysis identified that ESL students who used a reading comprehension program were almost twice as likely to be off track or out of the program as ESL students who did not use the program. Nurse educators need to evaluate student profile characteristics in a comprehensive way when determining risk of attrition.

Characterization and use of crystalline bacterial cell surface layers

Science.gov (United States)

Sleytr, Uwe B.; Sára, Margit; Pum, Dietmar; Schuster, Bernhard

2001-10-01

Crystalline bacterial cell surface layers (S-layers) are one of the most common outermost cell envelope components of prokaryotic organisms (archaea and bacteria). S-layers are monomolecular arrays composed of a single protein or glycoprotein species and represent the simplest biological membranes developed during evolution. S-layers as the most abundant of prokaryotic cellular proteins are appealing model systems for studying the structure, synthesis, genetics, assembly and function of proteinaceous supramolecular structures. The wealth of information existing on the general principle of S-layers have revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) functional groups on the surface and in the pores are aligned in well-defined positions and orientations and accessible for chemical modifications and binding functional molecules in very precise fashion; (iii) isolated S-layer subunits from a variety of organisms are capable of recrystallizing as closed monolayers onto solid supports (e.g., metals, polymers, silicon wafers) at the air-water interface, on lipid films or onto the surface of liposomes; (iv) functional domains can be incorporated in S-layer proteins by genetic engineering. Thus, S-layer technologies particularly provide new approaches for biotechnology, biomimetics, molecular nanotechnology, nanopatterning of surfaces and formation of ordered arrays of metal clusters or nanoparticles as required for nanoelectronics.

Application of ESL (Extended Shelf Life) Technology in Drinking Milk Production

OpenAIRE

ÜNVER, Naciye; ÇELİK, Şerafettin

2017-01-01

Nowadays pasteurization andUHT are the best known and most commonly used technologies in milk production.While products which have shorter shelf life and fresh taste are obtained byusing pasteurization, products which have longer shelf life but less desirabletaste are obtained by UHT technology. ESL technology is a new method which wasdeveloped to obtain a longer shelf life product than pasteurized milk andbetter sensory quality product than UHT milk. ESL milk includes technologiessuch as mic...

Teaching More Than English: Connecting ESL Students to Their Community through Service Learning

Science.gov (United States)

Russell, Natalie M.

2007-01-01

Language and cultural differences often cause English as a second language (ESL) students to feel alienated from their school and their community. As a result, they tend to make friends primarily within their own ESL classes and avoid interacting with mainstream students and getting involved in school activities. This article describes how…

Producing of multicomponent and composite surface layers

International Nuclear Information System (INIS)

Wierzchon, T.; Bielinski, P.; Michalski, A.

1995-01-01

The paper presents a new method of producing multicomponent and composite layers on steel substrate. The combination of nickel plating with glow-discharge bordering or impulse-plasma deposition method gives an opportunity to obtain good properties of surface layers. The results of examinations of carbon 45 (0.45%C) steel, nickel plated and then borided under glow discharge conditions or covered with TiN layers are presented. The corrosion and friction wear resistance of such layers are markedly higher than for layer produced on non nickel plated substrates. (author). 19 refs, 5 figs

An ESL Audio-Script Writing Workshop

Science.gov (United States)

Miller, Carla

2012-01-01

The roles of dialogue, collaborative writing, and authentic communication have been explored as effective strategies in second language writing classrooms. In this article, the stages of an innovative, multi-skill writing method, which embeds students' personal voices into the writing process, are explored. A 10-step ESL Audio Script Writing Model…

Mother Goose in the ESL Classroom.

Science.gov (United States)

Galeano, Karen

Mother Goose is well suited to use in the elementary ESL classroom for several reasons. The stories appeal to children's imagination, adhering to the principle that a good story should have surprise value, interesting characters, meaningful conflict, action, and realism. The natural rhythms help develop English intonation, and the stories…

Using Appreciative Pedagogy to Teach Literature to ESL Students

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Hung-Chang Liao

2011-12-01

Full Text Available This study explores how college literature instructors can use appreciative pedagogy in teaching students of English as a Second Language (ESL how to appreciate works of literature. The study of literature can be used as a channel for college students to access a wealth of human experience and to develop their sensitivity, empathy, and compassion toward other human beings. However, most ESL students in Taiwan are used to following their teachers’ interpretations and lack the confidence or experience to use their hearts to appreciate literature works. Appreciative pedagogy can be used in teaching literature. Through using the steps of the Discovery-DreamDesign-Delivery cycle designed by Cooperrider and Whitney (1999 in the practice of appreciative pedagogy, students can form a positive attitude towards their characteristics, values, and past experiences, thereby developing their self-confidence and competencies in studying literature. The quantitative instruments used were an English reading proficiency test and a student satisfaction survey. A fourteen-week experiment was conducted to evaluate the effectiveness of using appreciative pedagogy with ESL students studying literature. The research results revealed that students instructed with appreciative pedagogy had improved English reading proficiency and greater satisfaction with their class.

Surface layer temperature inversion in the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Pankajakshan, T.; Gopalakrishna, V.V.; Muraleedharan, P.M.; Reddy, G.V.; Araligidad, N.; Shenoy, Shrikant

Surface layer temperature inversion occurring in the Bay of Bengal has been addressed. Hydrographic data archived in the Indian Oceanographic Data Center are used to understand various aspects of the temperature inversion of surface layer in the Bay...

Mental Health and the ESL Classroom: A Guide for Teachers Working with Refugees.

Science.gov (United States)

Lucey, Moira; Chaffee, Marcia; Terry, Diane; Le Marbre, Joan; Stone, Betty; Wiencek, Donna

This manual guides English-as-a-Second-Language (ESL) teachers by outlining the complex burdens that refugee students carry and setting out concrete steps that ESL teachers can take in order to turn their classrooms into effective and welcoming teaching and learning environments. The seven sections focus on the following: (1) "The Refugee and…

Divergence in Curricular-Weight Teacher-Efforts and Student-Difficulties in Secondary School ESL

Science.gov (United States)

Abdul Gafoor, K.; Sreeja, C.

2013-01-01

The increasing importance of English as a global language, calls for an equally vigorous attempt to improving teaching and learning it in schools as a second language within and outside India. Highlighting the relevance of contextualising ESL learning by allowing for the needs of students and teachers in undertaking reforms to ESL learning, this…

Placement of English as a Second Language (ESL) Student Learners in Higher Education

Science.gov (United States)

Banegas, Michael R.

2013-01-01

Immigration into the U.S. will continue to increase in the coming years, thereby increasing the postsecondary enrollment of ESL students. Yet there is still a limited amount of research designed to evaluate which ESL placement programs are most effective. This study was designed to determine if the use of correct testing instruments would ensure…

Linking Research and Practice: Effective Strategies for Teaching Vocabulary in the ESL Classroom

Science.gov (United States)

Nam, Jihyun

2010-01-01

Vocabulary plays a pivotal role in the ESL classroom. Whereas a considerable amount of research has examined effective ESL vocabulary teaching and learning, missing are studies that provide examples of how to put various research findings into practice: that is, apply them to real texts including target vocabulary items. In order to close the gap…

Antiferromagnetic MnN layer on the MnGa(001) surface

Energy Technology Data Exchange (ETDEWEB)

Guerrero-Sánchez, J., E-mail: guerrero@cnyn.unam.mx; Takeuchi, Noboru

2016-12-30

Highlights: • A ferromagnetic Gallium terminated surface is stable before N incorporation. • After N incorporation, an antiferromagnetic MnN layer becomes stable in a wide range of chemical potential. • Spin density distribution shows an antiferromagnetic/ferromagnetic (MnN/MnGa) arrangement at the surface. - Abstract: Spin polarized first principles total energy calculations have been applied to study the stability and magnetic properties of the MnGa(001) surface and the formation of a topmost MnN layer with the deposit of nitrogen. Before nitrogen adsorption, surface formation energies show a stable gallium terminated ferromagnetic surface. After incorporation of nitrogen atoms, the antiferromagnetic manganese terminated surface becomes stable due to the formation of a MnN layer (Mn-N bonding at the surface). Spin density distribution shows a ferromagnetic/antiferromagnetic arrangement in the first surface layers. This thermodynamically stable structure may be exploited to growth MnGa/MnN magnetic heterostructures as well as to look for exchange biased systems.

An Interdisciplinary Theory-Based ESL Curriculum to Teach English as a Second Language

Directory of Open Access Journals (Sweden)

Brenda Fuentes

2011-11-01

Full Text Available Among Hispanic immigrants in the United States (US, learning English is considered necessary for economic and social achievement. Asa consequence, there is a high demand for English as a Second Language (ESL classes. Despite the recognized benefits of ESL programs,both at the individual and social levels, more research is needed to identify education strategies that effectively promote all aspects of learningEnglish as a second language. This article describes an ESL curriculum that incorporates a theory-based pedagogical approach specificallydesigned for immigrant Hispanic adults on the US-Mexico border region. The article also describes the implementation of the curriculum aswell as the results of the evaluation, which was conducted using both quantitative and qualitative methods. Quantitative results indicate thatthe participants significantly improved their English proficiency (L2. Qualitative results suggest that participants were positively impactedby both the content and pedagogical approaches used by the curriculum. Their experience with the ESL class was positive in general. It canbe concluded that the curriculum achieved its objective. This approach could serve as a model for second language teaching for adults

Proficiency in English sentence stress production by Cantonese speakers who speak English as a second language (ESL).

Science.gov (United States)

Ng, Manwa L; Chen, Yang

2011-12-01

The present study examined English sentence stress produced by native Cantonese speakers who were speaking English as a second language (ESL). Cantonese ESL speakers' proficiency in English stress production as perceived by English-speaking listeners was also studied. Acoustical parameters associated with sentence stress including fundamental frequency (F0), vowel duration, and intensity were measured from the English sentences produced by 40 Cantonese ESL speakers. Data were compared with those obtained from 40 native speakers of American English. The speech samples were also judged by eight native listeners who were native speakers of American English for placement, degree, and naturalness of stress. Results showed that Cantonese ESL speakers were able to use F0, vowel duration, and intensity to differentiate sentence stress patterns. Yet, both female and male Cantonese ESL speakers exhibited consistently higher F0 in stressed words than English speakers. Overall, Cantonese ESL speakers were found to be proficient in using duration and intensity to signal sentence stress, in a way comparable with English speakers. In addition, F0 and intensity were found to correlate closely with perceptual judgement and the degree of stress with the naturalness of stress.

Academic achievement and course taking among language minority youth in U.S. schools: Effects of ESL placement.

Science.gov (United States)

Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra

2010-03-01

The 1974 Lau decision requires that U.S. public schools ensure a meaningful education for students learning English. English as a Second Language (ESL) placement is an institutional response to the linguistic needs of these students; however, its academic implications remain largely unexplored. Using nationally representative data from the Educational Longitudinal Study (ELS), the effects of ESL placement on college preparatory course enrollment and academic achievement of language minority students are estimated, first with fixed effects regression models and then with multi-level propensity score matching techniques. While numerous school and individual level factors beyond language proficiency predict ESL placement, a significant negative estimated effect of ESL placement on science enrollment and cumulative GPA is consistently found. Perhaps more important, however, no positive effects of ESL placement on the achievement of language minority youth are found when accounting for English proficiency and other potential covariates.

The Departmentalization of the ESL Program.

Science.gov (United States)

Bolton, John K.

A review of prevailing patterns of sponsorship of college and university English as a second language (ESL) programs indicates that in community colleges, they tend to be housed in English departments. In four-year institutions they are generally in semi-autonomous units or institutes. The argument for departmental sponsorship is based on data…

Becoming Sociocultural Mediators: What All Educators Can Learn from Bilingual and ESL Teachers

Science.gov (United States)

Nieto, Sonia

2017-01-01

In this article, the author focuses specifically on how what she calls non-specialist teachers (i.e., those who are neither bilingual nor ESL teachers) can benefit from the practices of bilingual and ESL teachers, and how teacher educators can incorporate this knowledge in their curriculum and pedagogy. To do so, she uses examples from research…

Counting Words: Successful Sentences for Beginning ESL Adult Learners Using the Product Approach

Science.gov (United States)

Gardner, Susanne

2017-01-01

The majority of correctional students of English as a second language (ESL) in Maryland come to school with limited formal education in their first language. Education has not been prioritized, and formal writing ability is absent. It then becomes a challenge to motivate students to successful writing, as is required by the state. ESL students at…

Integrating health literacy and ESL: an interdisciplinary curriculum for Hispanic immigrants.

Science.gov (United States)

Soto Mas, Francisco; Mein, Erika; Fuentes, Brenda; Thatcher, Barry; Balcázar, Héctor

2013-03-01

Adult Hispanic immigrants are at a greater risk of experiencing the negative outcomes related to low health literacy, as they confront cultural and language barriers to the complex and predominately monolingual English-based U.S. health system. One approach that has the potential for simultaneously addressing the health, literacy, and language needs of Hispanics is the combination of health literacy and English as a second language (ESL) instruction. The purpose of the project was to evaluate the feasibility of using ESL instruction as a medium for improving health literacy among Hispanic immigrants. Objectives included the development, implementation, and evaluation of an interdisciplinary health literacy/ESL curriculum that integrates theories of health literacy and health behavior research and practice, sociocultural theories of literacy and communication, and adult learning principles. This article describes the curriculum development process and provides preliminary qualitative data on learners' experiences with the curriculum. Results indicate that the curriculum was attractive to participants and that they were highly satisfied with both the format and content. The curriculum described here represents one example of an audience-centered approach designed to meet the specific health and literacy needs of the Hispanic population on the U.S.-Mexico border. The combination of ESL and health literacy contributed to a perceived positive learning experience among participants. Interdisciplinary approaches to health literacy are recommended.

Surface Modification of Titanium with Heparin-Chitosan Multilayers via Layer-by-Layer Self-Assembly Technique

International Nuclear Information System (INIS)

Shu, Y.; Zou, J.; Ou, G.; Wang, L.; Li, Q.

2011-01-01

Extracellular matrix (ECM), like biomimetic surface modification of titanium implants, is a promising method for improving its biocompatibility. In this paper chitosan (Chi) and heparin (Hep) multilayer was coated on pure titanium using a layer-by-layer (LbL) self-assembly technique. The Hep-Chi multilayer growth was carried out by first depositing a single layer of positively charged poly-L-lysine (PLL) on the NaOH-treated titanium substrate (negatively charged surface), followed by alternate deposition of negatively charged Hep and positively charged Chi, and terminated by an outermost layer of Chi. The multilayer was characterized by DR-FTIR, SEM, and AFM, and osteoblasts were cocultured with the modified titanium and untreated titanium surfaces, respectively, to evaluate their cytocompatibility in vitro. The results confirmed that Hep-Chi multilayer was fabricated gradually on the titanium surface. The Hep-Chi multilayer-coated titanium improved the adhesion, proliferation and differentiation of osteoblasts. Thus, the approach described here may provide a basis for the preparation of modified titanium surfaces for use in dental or orthopedic implants

Durable superhydrophobic surfaces made by intensely connecting a bipolar top layer to the substrate with a middle connecting layer.

Science.gov (United States)

Zhi, Jinghui; Zhang, Li-Zhi

2017-08-30

This study reported a simple fabrication method for a durable superhydrophobic surface. The superhydrophobic top layer of the durable superhydrophobic surface was connected intensely to the substrate through a middle connecting layer. Glycidoxypropyltrimethoxysilane (KH-560) after hydrolysis was used to obtain a hydrophilic middle connecting layer. It could be adhered to the hydrophilic substrate by covalent bonds. Ring-open reaction with octadecylamine let the KH-560 middle layer form a net-like structure. The net-like sturcture would then encompass and station the silica particles that were used to form the coarse micro structures, intensely to increase the durability. The top hydrophobic layer with nano-structures was formed on the KH-560 middle layer. It was obtained by a bipolar nano-silica solution modified by hexamethyldisilazane (HMDS). This layer was connected to the middle layer intensely by the polar Si hydroxy groups, while the non-polar methyl groups on the surface, accompanied by the micro and nano structures, made the surface rather hydrophobic. The covalently interfacial interactions between the substrate and the middle layer, and between the middle layer and the top layer, strengthened the durability of the superhydrophobic surface. The abrasion test results showed that the superhydrophobic surface could bear 180 abrasion cycles on 1200 CW sandpaper under 2 kPa applied pressure.

Critical review of ESL curriculum: Practical application to the UAE context

Directory of Open Access Journals (Sweden)

Mary Cullinan

2016-05-01

Full Text Available This paper is a critical analysis of curriculum with a discussion of its main tenets and exploration of issues within the literature. The focus is on curriculum in English as a Second Language (ESL using critical applied linguistics as a framework. The ideas explored in the paper are synthesized and applied to ESL curriculum in the United Arab Emirates (UAE and includes a discussion on the feasibility and challenges of introducing a critical stance on curriculum in this context.

Multi-layer enhancement to polysilicon surface-micromachining technology

Energy Technology Data Exchange (ETDEWEB)

Sniegowski, J.J.; Rodgers, M.S. [Sandia National Labs., Albuquerque, NM (United States). Intelligent Micromachine Dept.

1997-10-01

A multi-level polysilicon surface-micromachining technology consisting of 5 layers of polysilicon is presented. Surface topography and film mechanical stress are the major impediments encountered in the development of a multilayer surface-micromachining process. However, excellent mechanical film characteristics have been obtained through the use of chemical-mechanical polishing for planarization of topography and by proper sequencing of film deposition with thermal anneals. Examples of operating microactuators, geared power-transfer mechanisms, and optical elements demonstrate the mechanical advantages of construction with 5 polysilicon layers.

Opinions from ESL instructors and students about curricula on hepatitis B for use in immigrant communities.

Science.gov (United States)

Coronado, Gloria D; Taylor, Victoria M; Hislop, T Gregory; Teh, Chong; Acorda, Elizabeth; Do, H Hoai; Chen, Hueifang; Thompson, Beti

2008-01-01

Chinese immigrants in Canada have a disproportionately high risk for hepatitis B compared with non-Hispanic Whites. Hepatitis B is the leading cause of hepatocellular carcinoma among Asian immigrants to North America. English-as-a-second-language (ESL) classes are an effective way of reaching newly immigrated individuals and are a potential channel for delivering health messages. Using data from 6 focus groups among ESL instructors and students, we characterized perceptions about activities that are successfully used in ESL classrooms and strategies for delivering hepatitis B information. RESULTS. Instructors and students generally reported that activities that focused on speaking and listening skills and that addressed content relevant to students' daily lives were successful in the classroom. Instructors generally avoided material that was irrelevant or too difficult to understand. Focus group participants offered strategies for delivering hepatitis B information in ESL classrooms; these strategies included addressing symptoms and prevention and not singling out a specific population subgroup to avoid stigmatization. These findings might assist efforts to develop ESL curricula that target immigrant populations.

Guidelines for Tutoring Adult ESL Students.

Science.gov (United States)

Frank, Marcella

This document is a copy of a talk regularly given to new volunteers of English in Action, a community-based organization that provides conversation practice to non-native English speakers. The volunteer tutors typically have no formal English-as-a-Second-Language (ESL) training. This packet is designed to help these volunteers be effective ESL…

ESL participation as a mechanism for advancing health literacy in immigrant communities.

Science.gov (United States)

Santos, Maricel G; Handley, Margaret A; Omark, Karin; Schillinger, Dean

2014-01-01

A reliance on the conceptualization of health literacy as functional skill has limited researchers' views of the adult English-as-a-second-language (ESL) context as a site for health literacy interventions. To explore the contributions of alternative views of literacy as social practice to health literacy research, the authors examined teacher survey data and learner outcomes data collected as part of a multiyear collaboration involving the California Diabetes Program, university researchers, and adult ESL teachers. The survey results (n=144 teachers) indicated that ESL teachers frequently model effective pedagogical practices that mediate social interaction around health content, the basis for acquiring new literacy skills and practices. In the classroom pilot (n=116 learners), the majority of learners reported they had learned about diabetes risk factors and prevention strategies, which affirmed existing healthy behaviors or prompted revision of unhealthy ones. About two thirds of the learners reported sharing preventive health content with members of out-of-school social networks. This study represents a first step in research efforts to account more fully for the mechanisms by which social interaction and social support facilitate health literacy outcomes in ESL contexts, which should complement what is already known about the development of health literacy as functional skill.

Evaluating Pragmatic Competence in Nigerian Undergraduates’ Language Errors within Descriptive ESL Writing

Directory of Open Access Journals (Sweden)

Anas Sa’idu Muhammad

2017-01-01

Full Text Available This study investigates the level of pragmatic competence for ESL writing skills among Nigerian undergraduates. Methodologically, it adopts descriptive research design within the explanatory framework of the QUAN-Qual model. The instruments used are descriptive essay text and focus group interview questions. In writing the descriptive essays, a total of 402 undergraduates’ participated through convenience sampling. Quantitatively, an independent samples t-test was carried out. The results indicated the females required putting more efforts towards improving their pragmatic competence in the ESL writing as they achieved a higher means for language errors, compared to that of the males. Moreover, the ttest value demonstrated that the females lacked skills in the pragmatic skills of mechanical structure, grammatical function, and sentence structures and this made them commit more language errors. Qualitatively, a focus group interview was held randomly with 12 participants out of the 402 undergraduates through purposive sampling. The results of the interview sessions revealed novelties of culture-specific, learning feasibility and the academic discourse as the key elements that constraint most of the Nigerian undergraduates ESL writing skills, particularly the females. Therefore, this study revealed strong implications on how best to develop Nigerian learners’ pragmatic competence in ESL writing skills

Differences in Less Proficient and More Proficient ESL College Writing in the Philippine Setting

Science.gov (United States)

Gustilo, Leah E.

2016-01-01

The present study aimed at characterizing what skilled or more proficient ESL college writing is in the Philippine setting through a contrastive analysis of three groups of variables identified from previous studies: resources, processes, and performance of ESL writers. Based on Chenoweth and Hayes' (2001; 2003) framework, the resource level…

Layer-by-Layer Method for the Synthesis and Growth of Surface Mounted Metal-Organic Frameworks (SURMOFs

Directory of Open Access Journals (Sweden)

Osama Shekhah

2010-02-01

Full Text Available A layer-by-layer method has been developed for the synthesis of metal-organic frameworks (MOFs and their deposition on functionalized organic surfaces. The approach is based on the sequential immersion of functionalized organic surfaces into solutions of the building blocks of the MOF, i.e., the organic ligand and the inorganic unit. The synthesis and growth of different types of MOFs on substrates with different functionalization, like COOH, OH and pyridine terminated surfaces, were studied and characterized with different surface characterization techniques. A controlled and highly oriented growth of very homogenous films was obtained using this method. The layer-by-layer method offered also the possibility to study the kinetics of film formation in more detail using surface plasmon resonance and quartz crystal microbalance. In addition, this method demonstrates the potential to synthesize new classes of MOFs not accessible by conventional methods. Finally, the controlled growth of MOF thin films is important for many applications like chemical sensors, membranes and related electrodes.

A literature review of surface alteration layer effects on waste glass behavior

International Nuclear Information System (INIS)

Feng, X.; Cunnane, J.C.; Bates, J.K.

1993-01-01

When in contact with an aqueous solution, nuclear waste glass is subject to a chemical attack that results in progressive alteration. During tills alteration, constituent elements of the glass pass into the solution; elements initially in solution diffuse into, or are adsorbed onto, the solid; and new phases appear. This results in the formation of surface layers on the reacted glass. The glass corrosion and radionuclide release can be better understood by investigating these surface layer effects. In the past decade, there have been numerous studies regarding the effects of surface layers on glass reactions. This paper presents a systematic analysis and summary of the past knowledge regarding the effects of surface layers on glass-water interaction. This paper describes the major formation mechanisms of surface layers; reviews the role of surface layers in controlling mass transport and glass reaction affinity (through crystalline phases, an amorphous silica, a gel layer, or all the components in the glass); and discusses how the surface layers contribute to the retention of radionuclides during glass dissolution

Coordinated and unique functions of the E-selectin ligand ESL-1 during inflammatory and hematopoietic recruitment in mice.

Science.gov (United States)

Sreeramkumar, Vinatha; Leiva, Magdalena; Stadtmann, Anika; Pitaval, Christophe; Ortega-Rodríguez, Inés; Wild, Martin K; Lee, Brendan; Zarbock, Alexander; Hidalgo, Andrés

2013-12-05

Beyond its well-established roles in mediating leukocyte rolling, E-selectin is emerging as a multifunctional receptor capable of inducing integrin activation in neutrophils, and of regulating various biological processes in hematopoietic precursors. Although these effects suggest important homeostatic contributions of this selectin in the immune and hematologic systems, the ligands responsible for transducing these effects in different leukocyte lineages are not well defined. We have characterized mice deficient in E-selectin ligand-1 (ESL-1), or in both P-selectin glycoprotein-1 (PSGL-1) and ESL-1, to explore and compare the contributions of these glycoproteins in immune and hematopoietic cell trafficking. In the steady state, ESL-1 deficiency resulted in a moderate myeloid expansion that became more prominent when both glycoproteins were eliminated. During inflammation, PSGL-1 dominated E-selectin binding, rolling, integrin activation, and extravasation of mature neutrophils, but only the combined deficiency in PSGL-1 and ESL-1 completely abrogated leukocyte recruitment. Surprisingly, we find that the levels of ESL-1 were strongly elevated in hematopoietic progenitor cells. These elevations correlated with a prominent function of ESL-1 for E-selectin binding and for migration of hematopoietic progenitor cells into the bone marrow. Our results uncover dominant roles for ESL-1 in the immature compartment, and a functional shift toward PSGL-1 dependence in mature neutrophils.

Contact mechanics for layered materials with randomly rough surfaces.

Science.gov (United States)

Persson, B N J

2012-03-07

The contact mechanics model of Persson is applied to layered materials. We calculate the M function, which relates the surface stress to the surface displacement, for a layered material, where the top layer (thickness d) has different elastic properties than the semi-infinite solid below. Numerical results for the contact area as a function of the magnification are presented for several cases. As an application, we calculate the fluid leak rate for laminated rubber seals.

Expansible apparatus for removing the surface layer from a concrete object

International Nuclear Information System (INIS)

Allen, C.H.

1979-01-01

A method and apparatus for removing the surface layer from a concrete object are described. The method consists of providing a hole having a circular wall in the surface layer of the object, the hole being at least as deep as the thickness of the surface layer to be removed, and applying an outward wedging pressure on the wall of the hole sufficient to spall the surface layer around the hole. By the proper spacing of an appropriate number of holes, it is possible to remove the entire surface layer. The apparatus consists of an elongated tubular-shaped body having a relatively short handle with a solid wall at one end. The wall of the remainder of the body contains a plurality of evenly spaced longitudinal cuts to form a relatively long expandable section. The outer end of the expandable section has an expandable, wedge-shaped spalling edge extending from the outer surface of the wall, perpendicular to the longitudinal axis of the body, and expanding means in the body for outwardly expanding the expandable section and forcing the spalling edge into the wall of a hole with sufficient outward pressure to spall away the surface layer of concrete. The method and apparatus are particularly suitable for removing surface layers of concrete which are radioactively contaminated

Advanced Cantonese ESL Learners' Use of a Monolingual ...

African Journals Online (AJOL)

monolingual dictionaries by Hong Kong advanced Cantonese ESL learners in the production of .... (COBUILD6), and one using Longman Dictionary of Contemporary English 5th ...... A Contrastive Study of Pocket Electronic Diction- aries and ...

Electrografted diazonium salt layers for antifouling on the surface of surface plasmon resonance biosensors.

Science.gov (United States)

Zou, Qiongjing; Kegel, Laurel L; Booksh, Karl S

2015-02-17

Electrografted diazonium salt layers on the surface of surface plasmon resonance (SPR) sensors present potential for a significant improvement in antifouling coatings. A pulsed potential deposition profile was used in order to circumvent mass-transport limitations for layer deposition rate. The influence of number of pulses with respect to antifouling efficacy was evaluated by nonspecific adsorption surface coverage of crude bovine serum proteins. Instead of using empirical and rough estimated values, the penetration depth and sensitivity of the SPR instrument were experimentally determined for the calculation of nonspecific adsorption surface coverage. This provides a method to better examine antifouling surface coatings and compare crossing different coatings and experimental systems. Direct comparison of antifouling performance of different diazonium salts was facilitated by a tripad SPR sensor design. The electrografted 4-phenylalanine diazonium chloride (4-APhe) layers with zwitterionic characteristic demonstrate ultralow fouling.

Fluorocarbon based atomic layer etching of Si_3N_4 and etching selectivity of SiO_2 over Si_3N_4

International Nuclear Information System (INIS)

Li, Chen; Metzler, Dominik; Oehrlein, Gottlieb S.; Lai, Chiukin Steven; Hudson, Eric A.

2016-01-01

Angstrom-level plasma etching precision is required for semiconductor manufacturing of sub-10 nm critical dimension features. Atomic layer etching (ALE), achieved by a series of self-limited cycles, can precisely control etching depths by limiting the amount of chemical reactant available at the surface. Recently, SiO_2 ALE has been achieved by deposition of a thin (several Angstroms) reactive fluorocarbon (FC) layer on the material surface using controlled FC precursor flow and subsequent low energy Ar"+ ion bombardment in a cyclic fashion. Low energy ion bombardment is used to remove the FC layer along with a limited amount of SiO_2 from the surface. In the present article, the authors describe controlled etching of Si_3N_4 and SiO_2 layers of one to several Angstroms using this cyclic ALE approach. Si_3N_4 etching and etching selectivity of SiO_2 over Si_3N_4 were studied and evaluated with regard to the dependence on maximum ion energy, etching step length (ESL), FC surface coverage, and precursor selection. Surface chemistries of Si_3N_4 were investigated by x-ray photoelectron spectroscopy (XPS) after vacuum transfer at each stage of the ALE process. Since Si_3N_4 has a lower physical sputtering energy threshold than SiO_2, Si_3N_4 physical sputtering can take place after removal of chemical etchant at the end of each cycle for relatively high ion energies. Si_3N_4 to SiO_2 ALE etching selectivity was observed for these FC depleted conditions. By optimization of the ALE process parameters, e.g., low ion energies, short ESLs, and/or high FC film deposition per cycle, highly selective SiO_2 to Si_3N_4 etching can be achieved for FC accumulation conditions, where FC can be selectively accumulated on Si_3N_4 surfaces. This highly selective etching is explained by a lower carbon consumption of Si_3N_4 as compared to SiO_2. The comparison of C_4F_8 and CHF_3 only showed a difference in etching selectivity for FC depleted conditions. For FC accumulation conditions

Developing Reading Comprehension Modules to Facilitate Reading Comprehension among Malaysian Secondary School ESL Students

Science.gov (United States)

Javed, Muhammad; Eng, Lin Siew; Mohamed, Abdul Rashid

2015-01-01

The study aims to develop a set of 6 Reading Comprehension Modules (RCMs) for Malaysian ESL teachers to facilitate different reading abilities of ESL students effectively. Different skill categories were selected for developing the RCMs. This article describes how and why diverse texts of varying length were adopted and adapted from various…

Cultural Competence in Alberta Schools: Perceptions of ESL Families in Four Major School Boards

Science.gov (United States)

Ngo, Hieu V.

2012-01-01

Complex linguistic, acculturative, and social needs of English-as-a-second-language (ESL) learners challenge the K-12 education system to develop cultural competence in working with culturally diverse families. This study surveyed 242 self-identified ESL students and their parents from four of Alberta's major school boards. Results of the survey…

A Review of the Four Most Widely-Used ESL Texts by LLA/LVA Affiliates.

Science.gov (United States)

Spelleri, Maria

This report reviews four English-as-a-Second-Language (ESL) textbooks, using criteria developed for volunteer-based organizations (VBOs). It illustrates the process that VBOs need to undertake prior to ESL textbook selection. The four texts include the following: "Laubach Way to English" (J. Macero and M. Lane), which focuses on linguistic rather…

Impromptu Speech Gamification for ESL/EFL Students

Science.gov (United States)

Girardelli, Davide

2017-01-01

Courses: Any introductory undergraduate public-speaking course, in particular in ESL/EFL contexts. Objectives: This single-class activity is intended to (1) build students' ability to communicate orally "off the cuff;" (2) foster students' understanding of the major organizational formats used in organizing speeches; and (3) increase…

Embedded and Direct Metacognitive Strategy Instruction and its Effects on the Metacognitive Awareness of Tertiary Level Malaysian ESL Listeners

Directory of Open Access Journals (Sweden)

Siew Ean Lye

2018-01-01

Full Text Available This small-scale quasi-experimental study compared the effects of metacognitive strategy instruction using two pedagogical approaches on the metacognitive awareness of Malaysian ESL listeners. Embedded and direct strategy instruction was delivered using the Metacognitive Pedagogical Sequence and Cognitive Academic Language Learning Approach instructional models respectively. 45 tertiary level students were randomly selected and assigned to two treatment groups to receive metacognitive instruction over a training period of five weeks. Paired-samples t-test results on participants‟ metacognitive awareness, as measured using the Metacognitive Awareness Listening Questionnaire (MALQ were inclusive despite significant improvements in their IELTS listening scores. No significant development was recorded in the overall MALQ scores but there were significant changes in three out of the five metacognitive awareness factors. Results further layered according to participants‟ listening proficiency levels (low, intermediate and high to examine if differences existed among the listening levels similarly showed no significant difference. These results suggest that ESL listeners‟ metacognitive awareness may not be easily developed with strategy instruction, regardless of the instructional approaches.

Critique of a language enrichment programme for Grade 4 ESL learners with limited English proficiency: a pilot study

Directory of Open Access Journals (Sweden)

Mirna Neli

2008-05-01

Full Text Available Some Grade 4 educators have expressed feelings of ineptitude regarding the support of ESL (English Second Language learners with limited English proficiency as they do not know how to support these learners effectively. Their litany emphasises ESL educators' need for supportive and preventive intervention. A Story-based Language Enrichment Programme (SLEP was compiled to suit the needs of educators teaching Grade 4 ESL learners with limited English proficiency. The programme was designed to maintain or improve the English proficiency of ESL learners. An intervention research method was followed to test the efficacy of SLEP. Forty teachers implemented SLEP over a six-week period. Thirty-nine teachers provided constructive feedback at the end of this period. Between 92% and 100% of the participants rated SLEP positively. Rural participants suggested some refinements to the programme. The overall conclusion was that SLEP makes a useful contribution to ESL practice.

MSFC Electrostatic Levitator (ESL) Rapid Quench System

Science.gov (United States)

SanSoucie, Michael P.; Craven, Paul D.; Rogers, Jan R.

2014-01-01

The NASA Marshall Space Flight Center (MSFC) Electrostatic Levitator (ESL) Laboratory is a unique facility for investigators studying high-temperature materials. The laboratory boasts two levitators in which samples can be levitated, heated, melted, undercooled, and resolidified, all without the interference of a container or data-gathering instrument. The ESL main chamber has been upgraded with the addition of a rapid quench system. This system allows samples to be dropped into a quench vessel that can be filled with a low melting point material, such as a gallium or indium alloy. Thereby allowing rapid quenching of undercooled liquid metals. Up to 8 quench vessels can be loaded into the quench wheel, which is indexed with LabVIEW control software. This allows up to 8 samples to be rapidly quenched before having to open the chamber. The system has been tested successfully on several zirconium samples. Future work will be done with other materials using different quench mediums. Microstructural analysis will also be done on successfully quench samples.

Becoming "Local" in ESL: Racism as Resource in a Hawai'i Public High School

Science.gov (United States)

Talmy, Steven

2010-01-01

Drawn from a 2.5 year critical ethnography in the ESL program of a Hawai'i public high school (Tradewinds High), this article examines racializing and racist conduct directed at Micronesian students by a group of old-timer ESL students, primarily of East/Southeast Asian inheritance. Racialization and racism directed at Micronesians positioned them…

Pedagogical strategies for teaching literacy to ESL immigrant students: a meta-analysis.

Science.gov (United States)

Adesope, Olusola O; Lavin, Tracy; Thompson, Terri; Ungerleider, Charles

2011-12-01

Many countries rely on immigrants for population growth and to maintain a skilled workforce. However, many such immigrants face literacy-related barriers to success in education and in the labour force. This meta-analysis reviews experimental and quasi-experimental studies to examine strategies for teaching English literacy to immigrant students. Following an exhaustive and systematic search for studies meeting pre-determined inclusion criteria, two researchers independently extracted data from 26 English as a Second Language (ESL) studies involving 3,150 participants. These participants consisted of ESL immigrant students in kindergarten through grade 6 who were exposed to English literacy instructional interventions. Measured outcomes were reading and writing. Mean effect sizes vary from small to large, depending on instructional interventions and outcome constructs. Across several different grade levels, settings, and methodological features, pedagogical strategies used in teaching ESL to immigrant students are associated with increased competence in reading and writing. Collaborative reading interventions, in which peers engage in oral interaction and cooperatively negotiate meaning and a shared understanding of texts, produced larger effects than systematic phonics instruction and multimedia-assisted reading interventions. The results show that the pedagogical strategies examined in this meta-analysis produced statistically significant benefits for students in all grade levels. The findings also show that students from low socio-economic status (SES) background benefit from ESL literacy interventions. However, significant heterogeneity was found in each subset. Educators and policy makers are encouraged to consider specific school contexts when making decisions about optimal pedagogical strategies. It is possible that contextual factors as well as ESL learner characteristics may influence the effectiveness of these strategies. To ensure literacy acquisition

Low-Energy Electron-Stimulated Luminescence of Thin H20 and D20 Layers on Pt(111)

International Nuclear Information System (INIS)

Petrik, Nikolay G.; Kimmel, Greg A.

2005-01-01

The electron-stimulated luminescence (ESL) from amorphous solid water and crystalline ice films deposited on Pt(111) at 100 K is investigated as a function of the film thickness, incident electron energy (5 ? 1000 eV), isotopic composition, and film structure. The ESL emission spectrum has a characteristic double-peaked shape that has been attributed to a transition between a superexcited state ( ) and the dissociative, first excited state ( ) in water: Comparing the electron-stimulated luminescence and O2 electron-stimulated desorption (ESD) yields versus incident electron energy, we find the ESL threshold blue-shifted from the O2 ESD threshold by ∼3 eV, which is close to the center of the emission spectrum near 400 nm and supports the assignment for the ESL. For thin films, radiative and non-radiative interactions with the substrate tend to quench the luminescence. The luminescence yield increases with coverage since the interactions with the substrate become less important. The ESL yield from D2O is ∼ 4 times higher than from H2O. Using layered films of H2O and D2O, this sizable isotopic effect on the ESL is exploited to spatially profile the luminescence emission within the ASW films. These experiments show that most of the luminescence is emitted from within the penetration depth of the incident electron. However, the results depend on the order of the isotopes in the film, and this asymmetry can be modeled by assuming some migration of the excited states within the film. The ESL is very sensitive to defects and structural changes in solid water, and the emission yield is significantly higher from amorphous films than from crystalline ice

Community in a Hurry: Social Contracts and Social Covenants in Short-Term ESL Courses

Science.gov (United States)

Martinsen, Rob A.

2009-01-01

Like many adult ESL instructors, the author has felt firsthand the challenges of creating community in short-term courses. Through his experience, he has noticed that in order to successfully build community in short-term ESL courses, teachers need to lay a foundation for social contracts and social covenants from the first day of the course and…

The English Definite Article: What ESL/EFL Grammars Say and What Corpus Findings Show

Science.gov (United States)

WonHo Yoo, Isaiah

2009-01-01

To ascertain whether what ESL/EFL grammars say is informed by what scholars discuss in the literature and supported by what corpus findings actually show, this paper first presents a brief overview of the literature on the English definite article and then compares popular ESL/EFL grammars' coverage of "the" and corpus findings on definite article…

Hidden Losses: How Demographics Can Encourage Incorrect Assumptions about ESL High School Students' Success

Science.gov (United States)

Toohey, Kelleen; Derwing, Tracey M.

2008-01-01

Data from ESL students' records in Vancouver are examined in the light of the BC Ministry of Education's claim that ESL high school students are more successful than students whose first language is English. We argue that the academic achievement of well-to-do students whose parents are skilled workers or entrepreneurs may mask the completion…

Dynamic air layer on textured superhydrophobic surfaces

KAUST Repository

Vakarelski, Ivan Uriev

2013-09-03

We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model. © 2013 American Chemical Society.

A Pedagogical Framework for Technology Integration in ESL Classrooms: The Promises and Challenges of Integration

Science.gov (United States)

Yang, Sha; Walker, Victoria

2015-01-01

Technologies have the potential to support language teaching and learning, but English as a Second Language (ESL) teachers in the United States (U.S.) either sparingly use technologies for instruction or use them at low level. Although previous research has indicated some promises and challenges faced by U.S. ESL teachers with integrating…

Effectiveness of Music on Vocabulary Acquisition, Language Usage, and Meaning for Mainland Chinese ESL Learners

Science.gov (United States)

Li, Xiangming; Brand, Manny

2009-01-01

Using an experimental approach, this study examined the relative effectiveness of varying the use of songs (lyrics and music) on vocabulary acquisition, language usage, and meaning for adult ESL students in the People's Republic of China. While the use of songs is generally enthusiastically endorsed by ESL teachers, few empirical studies have…

Marine Atmospheric Surface Layer and Its Application to Electromagnetic Wave Propagation

Science.gov (United States)

Wang, Q.

2015-12-01

An important application of the atmospheric surface layer research is to characterize the near surface vertical gradients in temperature and humidity in order to predict radar and radio communication conditions in the environment. In this presentation, we will give an overview of a new research initiative funded under the Office of Naval Research (ONR) Multi-University Research Initiative (MURI): the Coupled Air-Sea Processes and EM Ducting Research (CASPER). The objective is to fully characterize the marine atmospheric boundary layer (MABL) as an electromagnetic (EM) propagation environment with the emphasis of spatial and temporal heterogeneities and surface wave/swell effects, both of which contravene the underlying assumptions of Monin-Obukhov Similarity Theory (MOST) used in coupled environmental forecast models. Furthermore, coastal variability in the inversion atop the MABL presents a challenge to forecast models and also causes practical issues in EM prediction models. These issues are the target of investigation of CASPER. CASPER measurement component includes two major field campaigns: CASPER-East (2015 Duck, NC) and CASPER-West (2018 southern California). This presentation will show the extensive measurements to be made during the CASPER -East field campaign with the focus on the marine atmospheric surface layer measurements with two research vessels, two research aircraft, surface flux buoy, wave gliders, ocean gliders, tethered balloons, and rawinsondes. Unlike previous research on the marine surface layer with the focus on surface fluxes and surface flux parameterization, CASPER field campaigns also emphasize of the surface layer profiles and the validation of the surface layer flux-profile relationship originally derived over land surfaces. Results from CASPER pilot experiment and preliminary results from CASPER-East field campaign will be discussed.

Thiol-ene thermosets exploiting surface reactivity for layer-by-layer structures and control of penetration depth for selective surface reactivity

DEFF Research Database (Denmark)

Daugaard, Anders Egede; Westh, Andreas; Pereira Rosinha Grundtvig, Ines

Thiol-ene thermosets have been shown to be an efficient platform for preparation of functional polymer surfaces. Especially the effectiveness and versatility of the system has enabled a large variety of network properties to be obtained in a simple and straight-forward way. Due to its selectivity......, various thiols and allyl or other vinyl reactants can be used to obtain either soft and flexible1 or more rigid functional thermosets 2. The methodology permits use of etiher thermal or photochemical conditions both for matrix preparation as well as for surface functionalization. Due to excess reactive...... groups in thµe surface of thiol-ene thermosets, it is possible to prepare surface functional thermosets or to exploit the reactive groups for modular construction and subsequent chemical bonding. Here a different approach preparing monolithic layer-by-layer structures with controlled mechanical...

Amorphous surface layers in Ti-implanted Fe

International Nuclear Information System (INIS)

Knapp, J.A.; Follstaedt, D.M.; Picraux, S.T.

1979-01-01

Implanting Ti into high-purity Fe results in an amorphous surface layer which is composed of not only Fe and Ti, but also C. Implantations were carried out at room temperature over the energy range 90 to 190 keV and fluence range 1 to 2 x 10 16 at/cm 2 . The Ti-implanted Fe system has been characterized using transmission electron microscopy (TEM), ion backscattering and channeling analysis, and (d,p) nuclear reaction analysis. The amorphous layer was observed to form at the surface and grow inward with increasing Ti fluence. For an implant of 1 x 10 17 Ti/cm 2 at 180 keV the layer thickness was 150 A, while the measured range of the implanted Ti was approx. 550 A. This difference is due to the incorporation of C into the amorphous alloy by C being deposited on the surface during implantation and subsequently diffusing into the solid. Our results indicate that C is an essential constituent of the amorphous phase for Ti concentrations less than or equal to 10 at. %. For the 1 x 10 17 Ti/cm 2 implant, the concentration of C in the amorphous phase was approx. 25 at. %, while that of Ti was only approx. 3 at. %. A higher fluence implant of 2 x 10 17 Ti/cm 2 produced an amorphous layer with a lower C concentration of approx. 10 at. % and a Ti concentration of approx. 20 at. %

The Relationship between Reading Proficiency and Reading Strategy Use: A Study of Adult ESL Learners

Science.gov (United States)

Huang, Jiuhan; Nisbet, Deanna

2014-01-01

This article explores the relationship between reading strategy use and reading proficiency among 121 adult ESL learners. Reading strategy use was measured by the SORS, and reading proficiency was determined by the CASAS Reading Test and BEST Literacy Test. Findings of the study reveal that (a) adult ESL learners are active strategies users; (b)…

What Prevents ESL/FL Writers from Avoiding Plagiarism? Analyses of 10 North-American College Websites.

Science.gov (United States)

Yamada, Kyoko

2003-01-01

Discusses how inexperienced English-as-a-Second/Foreign-Language (ESL/EFL) writers can be helped to avoid plagiarism. Analyzes 10 North American Web sites on plagiarism, which provide a window to understanding how this issue has been problemitized and explained in Anglophone academic contexts. Concludes ESL/EFL may need to emphasize the role of…

Computer simulation to predict energy use, greenhouse gas emissions and costs for production of extended shelf-life (ESL) milk using microfiltration

Science.gov (United States)

Extended shelf-life (ESL) milk has a shelf life between that of high-temperature short-time (HTST) and ultrahigh temperature (UHT) pasteurized milk. ESL milk is usually pasteurized at temperatures exceeding 125 deg C which may give the milk a cooked taste. ESL milk produced using crossflow microfilt...

The Impact of a Computer-Mediated Shadowing Activity on ESL Speaking Skill Development: A Pilot Study

Science.gov (United States)

Mishima, Masakazu; Cheng, Lixia

2017-01-01

This pilot study explored the instructional value and potential of a computer-mediated shadowing activity for improving English as a Second Language (ESL) learners' speech intelligibility. Prospective International Teaching Assistants (ITAs), who were enrolled in an ESL classroom communication class at a large public university, completed a…

The Role of Transitions in ESL Instruction

Science.gov (United States)

Steinman, Linda

2013-01-01

Transitions in ESL contexts generally refer to those linking words placed between sentences and between paragraphs. Transitions in writing (and in speaking) are helpful; they facilitate coherence and cohesion when used correctly. Understanding them when reading allows us to join the writer in seeing why and how idea B follows idea A. In this…

Prenatal Care: A Content-Based ESL Curriculum.

Science.gov (United States)

Hassel, Elissa Anne

A content-based curriculum in English as a Second Language (ESL) focusing on prenatal self-care is presented. The course was designed as a solution to the problem of inadequate prenatal care for limited-English-proficient Mexican immigrant women. The first three sections offer background information on and discussion of (1) content-based ESL…

BRIDGING THE REAL WORLD ENGLISHES IN THE RURAL ESL CLASSROOM THROUGH TRANSLATION

Directory of Open Access Journals (Sweden)

Nik Zaitun Mohamed

2015-12-01

Full Text Available Translation can play a role in the development of communicative abilities since speakers are often engaged in the work of sharing and negotiating meaning. It fosters speculation and discussion, apart from developing abilities considered fundamental for communication, such as interpretation, negotiation, and expression of meaning. However, there are views against translation in the ESL classrooms even though the method has been applied in the pedagogical process. As a result, ESL students who are weak in English are not given the opportunity to excel in the second language from their own bilingual strength. This paper attempts to study and disclose in what ways pedagogogical translation in rural ESL classrooms in Sabah is reflected into practice, thereby assessing whether the gap between pedagogical translation and translation pedagogy has beeen been bridged. In this case study, five primary teachers were selected and their knowledge and practice of translation were assessed through qualitative content analysis in pre- teaching, while teaching and post-teaching activities. A translation framework has been designed and used in assessing the teachers’ performances in using translation. This pilot study reveals that teachers have translated from the first language (L1 into the second language (L2 as a means to help students to understand the content of the English lesson. They did not have adequate knowedge on translation strategies. Thus, the designed translation framework may be used by teachers as a guide in using translation in the ESL context.

Formation of nanocrystalline surface layers in various metallic materials by near surface severe plastic deformation

Directory of Open Access Journals (Sweden)

Masahide Sato, Nobuhiro Tsuji, Yoritoshi Minamino and Yuichiro Koizumi

2004-01-01

Full Text Available The surface of the various kinds of metallic materials sheets were severely deformed by wire-brushing at ambient temperature to achieve nanocrystalline surface layer. The surface layers of the metallic materials developed by the near surface severe plastic deformation (NS-SPD were characterized by means of TEM. Nearly equiaxed nanocrystals with grain sizes ranging from 30 to 200 nm were observed in the near surface regions of all the severely scratched metallic materials, which are Ti-added ultra-low carbon interstitial free steel, austenitic stainless steel (SUS304, 99.99 wt.%Al, commercial purity aluminum (A1050 and A1100, Al–Mg alloy (A5083, Al-4 wt.%Cu alloy, OFHC-Cu (C1020, Cu–Zn alloy (C2600 and Pb-1.5%Sn alloy. In case of the 1050-H24 aluminum, the depth of the surface nanocrystalline layer was about 15 μm. It was clarified that wire-brushing is an effective way of NS-SPD, and surface nanocrystallization can be easily achieved in most of metallic materials.

Mainstream Teacher Candidates' Perspectives on ESL Writing: The Effects of Writer Identity and Rater Background

Science.gov (United States)

Kang, Hyun-Sook; Veitch, Hillary

2017-01-01

This study explored the extent to which the ethnic identity of a writer and the background (gender and area of teaching) of a rater can influence mainstream teacher candidates' evaluation of English as a second language (ESL) writing, using a matched-guise method. A one-page essay was elicited from an ESL learner enrolled in an intensive English…

Role of ESLs in reaching BARC technologies to rural India - experience at Kaiga

International Nuclear Information System (INIS)

Nayak, P.D.; Ujjappa, K.M.; Ravi, P.M.; Hegde, A.G.

2009-01-01

Considering the various site selection requirements, most of the nuclear power plants in India under Nuclear Power Corporation of India Limited (NPCIL), are located in very remote locations. The Environmental Survey Laboratories (ESLs) under Health Physics Division, BARC are located at all Nuclear Power Stations. This paper presents the experience gained at ESL, KGS, Kaiga in acting as an interface between BARC, the technology developer and the rural public, the end user of the technology. (author)

The design of an instrument to evaluate software for EFL/ESL pronunciation teaching

Directory of Open Access Journals (Sweden)

Cristiana Gomes de Freitas Menezes Martins

2016-01-01

Full Text Available http://dx.doi.org/10.5007/2175-8026.2016v69n1p141 The purpose of this study was to develop and test the reliability and validity of an instrument to evaluate the extent to which software programs teach English as a Foreign Language and/or Second Language (EFL/ESL pronunciation following the principles of the Communicative Approach (Celce-Murcia et al, 2010, thus having the potential to develop English pronunciation. After the development of the instrument, 46 EFL/ESL teachers used it to analyze an online version of the software program Pronunciation Power 2. The responses of the participants were submitted to statistical analysis and the validity and reliability of the instrument were tested. The good reliability indexes obtained in this study suggest the instrument has some degree of validity for evaluating how well an ESL/EFL pronunciation teaching software program potentially develops English pronunciation.

Assessing Reading Strategy Training based on CALLA model in EFL and ESL Context

Directory of Open Access Journals (Sweden)

Alireza Karbalaei

2011-04-01

Full Text Available Reading strategies instruction is currently gaining much attention as an effective means of enhancing reading comprehension. In this research, we examined the effect of Underlining Strategy Intervention, based on the CALLA model in EFL and ESL contexts. A group of 189 college students were randomly selected from different universities in Iran and India. Based on a proficiency test, students were grouped into high, moderate, and low level. Then, the underlining strategy was taught during the treatment sessions. The results suggest that intervention or explicit instruction was effective in increasing the reading comprehension of both Iranian and Indian students although Indian ESL students were able to perform better in comparison to their Iranian EFL counterparts. There was no significant difference between proficiency level and students' performance in reading comprehension in EFL and ESL contexts. In addition, there was no significant difference between males and females in both contexts.

Dissolution model for a glass having an adherent insoluble surface layer

International Nuclear Information System (INIS)

Harvey, K.B.; Larocque, C.A.B.

1990-01-01

Waste form glasses that contain substantial quantities of iron, manganese, and aluminum oxides, such as the Savannah River SRL TDS-131 glass, form a thick, hydrated surface layer when placed in contact with water. The dissolution of such a glass has been modeled with the Savannah River Model. The authors showed previously that the equations of the Savannah River Model could be fitted to published experimental data if a time-dependent diffusion coefficient was assumed for species of diffusing through the surface layer. The Savannah River Model assumes that all of the material dissolved from the glass enters solution, whereas it was observed that substantial quantities of material were retained in the surface layer. An alternative model, presented contains a mass balance equation that allows material either to enter solution or to be retained in the surface layer. It is shown that the equations derived using this model can be fitted to the published experimental data assuming a constant diffusion coefficient for species diffusing through the surface layer

Cybernetics: A Model for Feedback in the ESL Classroom.

Science.gov (United States)

Zamel, Vivian

1981-01-01

Examines cybernetics as a model which provides framework with which to view communicators and the communications in the ESL classroom because it implies the kind of feedback the learner can assimilate and act upon. (Author/BK)

[A surface reacted layer study of titanium-zirconium alloy after dental casting].

Science.gov (United States)

Zhang, Y; Guo, T; Li, Z; Li, C

2000-10-01

To investigate the influence of the mold temperature on the surface reacted layer of Ti-Zr alloy castings. Ti-Zr alloy was casted into a mold which was made of a zircon (ZrO2.SiO2) for inner coating and a phosphate-bonded material for outer investing with a casting machine (China) designed as vacuum, pressure and centrifuge. At three mold temperatures (room temperature, 300 degrees C, 600 degrees C) the Ti-Zr alloy was casted separately. The surface roughness of the castings was calculated by instrument of smooth finish (China). From the surface to the inner part the Knoop hardness and thickness in reacted layer of Ti-Zr alloy casting was measured. The structure of the surface reacted layer was analysed by SEM. Elemental analyses of the interfacial zone of the casting was made by element line scanning observation. The surface roughness of the castings was increased significantly with the mold temperature increasing. At a higher mold temperature the Knoop hardness of the reactive layer was increased. At the three mold temperature the outmost surface was very hard, and microhardness data decreased rapidly where they reached constant values. The thickness was about 85 microns for castings at room temperature and 300 degrees C, 105 microns for castings at 600 degrees C. From the SEM micrograph of the Ti-Zr alloy casting, the surface reacted layer could be divided into three different layers. The first layer was called non-structure layer, which thickness was about 10 microns for room temperature group, 20 microns for 300 degrees C and 25 microns for 600 degrees C. The second layer was characterized by coarse-grained acicular crystal, which thickness was about 50 microns for three mold temperatures. The third layer was Ti-Zr alloy. The element line scanning showed non-structure layer with higher level of element of O, Al, Si and Zr, The higher the mold temperature during casting, the deeper the Si permeating and in the second layer the element Si could also be found

Low-cycle fatigue of sheet elements with ''soft'' surface layer

International Nuclear Information System (INIS)

Luk'yanov, V.F.; Kharchenko, V.Ya.; Berezutskij, V.I.; Ovsyannikov, V.G.

1978-01-01

Investigated are regularities of low-cycle fatigue of bimetallic sheet constructions made of chrome-nickel-molybdenum steel, plated with a low-alloyed steel with a reduced yield limit. Static repeated bending tests have been carried out using two-layer samples. The surface layer has been shown to increase resistance to nucleation and propagation of cracks under pulsating load if stresses are not more than 2 times higher than the yield limit. Increase in stresses leads to elastoplastic deformation and reduces durability. The positive effect of the surface layer is advisable to be used when welding-up surface defects and strengthening welded joints of high-strength steels

Covalent assembly of poly(ethyleneimine) via layer-by-layer deposition for enhancing surface density of protein and bacteria attachment

Energy Technology Data Exchange (ETDEWEB)

Xia, Bing, E-mail: xiabing@njfu.edu.cn [Key Laboratory of Forest Genetics and Biotechnology (Ministry of Education of China), Nanjing Forestry University, Nanjing 210037 (China); Advanced Analysis and Testing Center, Nanjing Forestry University, Nanjing 210037 (China); Shi, Jisen; Dong, Chen; Zhang, Wenyi; Lu, Ye [Key Laboratory of Forest Genetics and Biotechnology (Ministry of Education of China), Nanjing Forestry University, Nanjing 210037 (China); Guo, Ping [Nanjing College of Information Technology, Nanjing 210023 (China)

2014-02-15

Covalently assembly of low molecular weight poly(ethyleneimine) was introduced to glass surfaces via glutaraldehyde crosslinking, with focus on its application on protein immobilization or bacteria attachment. Characterizations of Fourier transform infrared spectroscopy and ellipsometry measurement revealed a stepwise growth of poly(ethyleneimine) films by layer-by-layer deposition. After fluorescein isothiocyanate labelling, photoluminescence spectroscopy measurement indicated that the amount of surface accessible amine groups had been gradually enhanced with increasing poly(ethyleneimine) layers deposition. As compared with traditional aminosilanized surfaces, the surface density of amine groups was enhanced by ∼11 times after five layers grafting, which resulted in ∼9-time increasing of surface density of immobilized bovine serum albumin. Finally, these as-prepared PEI multi-films with excellent biocompatibility were adopted as culture substrates to improve Escherichia coli adherence, which showed that their surface density had been increased by ∼251 times.

CHARACTERIZING SURFACE LAYERS IN NITINOL USING X-RAY PHOTOELECTRON SPECTROSCOPY

Energy Technology Data Exchange (ETDEWEB)

Christopfel, R.; Mehta, A.

2008-01-01

Nitinol is a shape memory alloy whose properties allow for large reversible deformations and a return to its original geometry. This nickel-titanium (NiTi) alloy has become a material used widely in the biomedical fi eld as a stent to open up collapsed arteries. Both ambient and biological conditions cause surface oxidation in these devices which in turn change its biocompatibility. The thickness of oxidized layers can cause fractures in the material if too large and can allow for penetration if too thin. Depending on the type and abundance of the chemical species on or near the surface, highly toxic metal ions can leak into the body causing cell damage or even cell death. Thus, biocompatibility of such devices is crucial. By using highly surface sensitive x-ray photoelectron spectroscopy to probe the surface of these structures, it is possible to decipher both layer composition and layer thickness. Two samples, both of which were mechanically polished, were investigated. Of the two samples, one was then exposed to a phosphate buffered saline (PBS) solution to mimic the chemical properties of blood, while the other remained unexposed. Although both samples were found to have oxide layers of appropriate thickness (on the order of a few nm), it was found that the sample exposed to the saline solution had a slightly thicker oxide layer and more signifi cantly, a phosphate layer very near the surface suggesting toxic metal components are well contained within the sample. These are considerable indications of a biocompatible device.

Layer-dependent surface potential of phosphorene and anisotropic/layer-dependent charge transfer in phosphorene-gold hybrid systems.

Science.gov (United States)

Xu, Renjing; Yang, Jiong; Zhu, Yi; Yan, Han; Pei, Jiajie; Myint, Ye Win; Zhang, Shuang; Lu, Yuerui

2016-01-07

The surface potential and the efficiency of interfacial charge transfer are extremely important for designing future semiconductor devices based on the emerging two-dimensional (2D) phosphorene. Here, we directly measured the strong layer-dependent surface potential of mono- and few-layered phosphorene on gold, which is consistent with the reported theoretical prediction. At the same time, we used an optical way photoluminescence (PL) spectroscopy to probe charge transfer in the phosphorene-gold hybrid system. We firstly observed highly anisotropic and layer-dependent PL quenching in the phosphorene-gold hybrid system, which is attributed to the highly anisotropic/layer-dependent interfacial charge transfer.

Pedagogy in Speaking: Challenges Addressed by Teacher-Student in the ESL Context

Directory of Open Access Journals (Sweden)

Md. Kawser Ahmed

2018-05-01

Full Text Available Teaching speaking is perhaps one of the major challenges for teachers teaching in English as a Second Language (ESL classroom environment. Like writing, speaking is not linear and easy approach to ensure the best utilization among learners.  Since speaking is a real life event and face to face conversation, it needs more sophisticated care, practice oriented session for the students and effective means to implement it in the ESL situation. Even language experts often grope to outline effective and mediocre way to help learners have a good understanding in speaking.  This paper attempts to delineate the focal points where teachers and students face problems in teaching and learning speaking. It immensely chalks out with methodological study, qualitative data analysis and the underlining factors ESL teachers face enormously in the pedagogy of speaking for second language learners. My paper will outline the pedagogical tenets of speaking in the realistic non-native set ups and diagnose the impediments faced by learners when they are supposed to speak and by teachers when they teach speaking for their students.

ESL Readers' Comprehension Performance: The Chinese Secondary Context

Science.gov (United States)

Chau, Juliana; Wu, Winnie; Chen, Julia; Lughmani, Shari

2012-01-01

Recent research in reading comprehension in Western settings has focused on collecting evidence from reading tests that would measure relevant ESL reading constructs to inform reading instruction and assessment. Similar studies in non-Western contexts, however, remain under-reported. This study involved 958 senior secondary Hong Kong (Chinese)…

Advanced Cantonese ESL Learners' Use of a Monolingual ...

African Journals Online (AJOL)

This article reports on the results of a research study which investigated the use of monolingual dictionaries by Hong Kong advanced Cantonese ESL learners in the production of target language sentences. Thirty-one English majors participated in a sentence completion task and a sentence construction task with and ...

The ESL classroom teaching, critical practice, and community development

CERN Document Server

Morgan, Brian D

1998-01-01

Brian Morgan uses his own teaching experience in Canada and China to investigate the complexities of teaching English as a second language to those newly arrived in Canada and to suggest ways of becoming a more effective ESL teacher.

ESL Students’ Perceptions of the use of Higher Order Thinking Skills in English Language Writing

Directory of Open Access Journals (Sweden)

Malini Ganapathy

2014-10-01

Full Text Available The transformation of the education curriculum in the Malaysia Education Development Plan (PPPM 2013-2025 focuses on the Higher Order Thinking (HOT concept which aims to produce knowledgeable students who are critical and creative in their thinking and can compete at the international level. HOT skills encourage students to apply, analyse, evaluate and think creatively in and outside the classroom. The purpose of this exploratory study was to investigate the impact of using HOT skills in a secondary ESL writing classroom. A total of 120 Form Two ESL students from three intact classes participated in this study. The students experienced project and group-based work both independently and collaboratively in groups during their writing lessons. The findings from the focus group interviews revealed the following student perceptions: felt engaged in active learning, experienced learner autonomy, developed their writing, researching and personal skills. The implications of this study suggest that using HOT skills in ESL writing lessons facilitate students’ writing ability and interest and it is recommended that HOT skills be explicitly infused in the teaching and learning of writing activities in ESL classrooms.

E-selectin ligand-1 (ESL-1) is a novel adiponectin binding protein on cell adhesion.

Science.gov (United States)

Yamamoto, Hiroyasu; Kuroda, Nana; Uekita, Hiromi; Kochi, Ikoi; Matsumoto, Akane; Niinaga, Ryu; Funahashi, Tohru; Shimomura, Iichiro; Kihara, Shinji

2016-02-05

Adiponectin (APN) is an adipocyte-derived bioactive molecule with anti-diabetic and anti-atherogenic properties. Although anti-diabetic effects are mostly mediated by the adiponectin receptors AdipoR1 and AdipoR2, the anti-atherogenic mechanisms have not been fully elucidated. In this study, we identified E-selectin ligand (ESL)-1 as a novel APN-binding protein by mass spectrometry analysis of HepG2 cell-derived immunoprecipitant with an anti-APN antibody. Cell adhesion assays using fluorescence-labelled monocyte cell line THP-1 cells and human umbilical vein endothelial cells (HUVECs) revealed that APN-pre-treated THP-1 cells had reduced binding ability to HUVECs. This APN-mediated suppressive effect on monocyte binding to endothelial cells was partially abrogated by targeting ESL-1 with shRNA in THP-1 cells. In addition, serial mutagenesis analysis disclosed that five extracellular amino acids close to the N-terminus of ESL-1 were essential for binding with APN. Our results highlight the fact that interaction between APN and ESL-1 could provide a fundamental mechanism underlying the anti-atherogenic properties of APN. Copyright © 2016 Elsevier Inc. All rights reserved.

Rational Deletion Cloze Processing Strategies: ESL and Native English.

Science.gov (United States)

Markham, Paul L.

1987-01-01

Explores cloze sensitivity to global comprehension by means of retrospective interview techniques. No significant differences were found between English as a second language (ESL) college students (N=14) and native English-speaking students (N=14) in their processing strategies. (Author/CB)

Generation Mechanism of Work Hardened Surface Layer in Metal Cutting

Science.gov (United States)

Hikiji, Rikio; Kondo, Eiji; Kawagoishi, Norio; Arai, Minoru

Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effects of the cutting conditions and the complicated factors on the machined surface integrity are the serious problems. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force acting point, the coefficient of the thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.

Surface rheology of saponin adsorption layers.

Science.gov (United States)

Stanimirova, R; Marinova, K; Tcholakova, S; Denkov, N D; Stoyanov, S; Pelan, E

2011-10-18

Extracts of the Quillaja saponaria tree contain natural surfactant molecules called saponins that very efficiently stabilize foams and emulsions. Therefore, such extracts are widely used in several technologies. In addition, saponins have demonstrated nontrivial bioactivity and are currently used as essential ingredients in vaccines, food supplements, and other health products. Previous preliminary studies showed that saponins have some peculiar surface properties, such as a very high surface modulus, that may have an important impact on the mechanisms of foam and emulsion stabilization. Here we present a detailed characterization of the main surface properties of highly purified aqueous extracts of Quillaja saponins. Surface tension isotherms showed that the purified Quillaja saponins behave as nonionic surfactants with a relatively high cmc (0.025 wt %). The saponin adsorption isotherm is described well by the Volmer equation, with an area per molecule of close to 1 nm(2). By comparing this area to the molecular dimensions, we deduce that the hydrophobic triterpenoid rings of the saponin molecules lie parallel to the air-water interface, with the hydrophilic glucoside tails protruding into the aqueous phase. Upon small deformation, the saponin adsorption layers exhibit a very high surface dilatational elasticity (280 ± 30 mN/m), a much lower shear elasticity (26 ± 15 mN/m), and a negligible true dilatational surface viscosity. The measured dilatational elasticity is in very good agreement with the theoretical predictions of the Volmer adsorption model (260 mN/m). The measured characteristic adsorption time of the saponin molecules is 4 to 5 orders of magnitude longer than that predicted theoretically for diffusion-controlled adsorption, which means that the saponin adsorption is barrier-controlled around and above the cmc. The perturbed saponin layers relax toward equilibrium in a complex manner, with several relaxation times, the longest of them being around 3

How to Create a Learning-Centered ESL Program

Science.gov (United States)

Bista, Krishna

2011-01-01

This paper reviews the major features of learning-centered community colleges that offer educational programs and experiences for learners, based on individual need. By citing some exemplary learning colleges, the author examines the concepts and ideas of learning-centered colleges in teaching English as a Second Language (ESL) programs. An…

Layer-by-Layer Heparinization of the Cell Surface by Using Heparin-Binding Peptide Functionalized Human Serum Albumin.

Science.gov (United States)

Song, Guowei; Hu, Yaning; Liu, Yusheng; Jiang, Rui

2018-05-20

Layer-by-layer heparinization of therapeutic cells prior to transplantation is an effective way to inhibit the instant blood-mediated inflammatory reactions (IBMIRs), which are the major cause of early cell graft loss during post-transplantation. Here, a conjugate of heparin-binding peptide (HBP) and human serum albumin (HSA), HBP-HSA, was synthesized by using heterobifunctional crosslinker. After the first heparin layer was coated on human umbilical vein endothelial cells (HUVECs) by means of the HBP-polyethylene glycol-phospholipid conjugate, HBP-HSA and heparin were then applied to the cell surface sequentially to form multiple layers. The immobilization and retention of heparin were analyzed by confocal microscopy and flow cytometry, respectively, and the cytotoxity of HBP-HSA was further evaluated by cell viability assay. Results indicated that heparin was successfully introduced to the cell surface in a layer-by-layer way and retained for at least 24 h, while the cytotoxity of HBP-HSA was negligible at the working concentration. Accordingly, this conjugate provides a promising method for co-immobilization of heparin and HSA to the cell surface under physiological conditions with improved biocompatibility.

Virtual ellipsometry on layered micro-facet surfaces.

Science.gov (United States)

Wang, Chi; Wilkie, Alexander; Harcuba, Petr; Novosad, Lukas

2017-09-18

Microfacet-based BRDF models are a common tool to describe light scattering from glossy surfaces. Apart from their wide-ranging applications in optics, such models also play a significant role in computer graphics for photorealistic rendering purposes. In this paper, we mainly investigate the computer graphics aspect of this technology, and present a polarisation-aware brute force simulation of light interaction with both single and multiple layered micro-facet surfaces. Such surface models are commonly used in computer graphics, but the resulting BRDF is ultimately often only approximated. Recently, there has been work to try to make these approximations more accurate, and to better understand the behaviour of existing analytical models. However, these brute force verification attempts still emitted the polarisation state of light and, as we found out, this renders them prone to mis-estimating the shape of the resulting BRDF lobe for some particular material types, such as smooth layered dielectric surfaces. For these materials, non-polarising computations can mis-estimate some areas of the resulting BRDF shape by up to 23%. But we also identified some other material types, such as dielectric layers over rough conductors, for which the difference turned out to be almost negligible. The main contribution of our work is to clearly demonstrate that the effect of polarisation is important for accurate simulation of certain material types, and that there are also other common materials for which it can apparently be ignored. As this required a BRDF simulator that we could rely on, a secondary contribution is that we went to considerable lengths to validate our software. We compare it against a state-of-art model from graphics, a library from optics, and also against ellipsometric measurements of real surface samples.

Stormwater infiltration and surface runoff pollution reduction performance of permeable pavement layers.

Science.gov (United States)

Niu, Zhi-Guang; Lv, Zhi-Wei; Zhang, Ying; Cui, Zhen-Zhen

2016-02-01

In this paper, the laboratory-scale permeable pavement layers, including a surface permeable brick layer, coarse sand bedding layers (thicknesses = 2, 3.5, and 5 cm), and single-graded gravel sub-base layers (thicknesses = 15, 20, 25, and 30 cm), were built to evaluate stormwater infiltration and surface runoff pollution reduction performance. And, the infiltration rate (I) and concentrations of suspended solids (SS), total phosphorus (TP), chemical oxygen demand (COD), ammonia nitrogen, and total nitrogen (TN) were measured under the simulated rainfall intensity of 72.4 mm/h over duration of 60 min. The results indicate that the thickness factor primarily influences the infiltration rate and pollutant removal rate. The highest steady infiltration rate was for surface brick layer 51.0 mm/h, for 5-cm sand bedding layer 32.3 mm/h, and for 30-cm gravel sub-base layer 42.3 mm/h, respectively. The SS average removal rate was relative higher (79.8 ∼ 98.6 %) for all layers due to the interception and filtration. The average removal rates of TP and COD were for surface layer 71.2 and 24.1 %, for 5-cm bedding layer 54.8 and 9.0 %, and for 20-cm sub-base layer 72.2 and 26.1 %. Ammonia nitrogen and TN cannot steadily be removed by layers according to the experiment results. The optimal thickness of bedding sands was 5 cm, and that of sub-base gravels was 20 ∼ 30 cm.

Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

KAUST Repository

Vakarelski, Ivan Uriev

2012-09-12

In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

KAUST Repository

Vakarelski, Ivan Uriev; Patankar, Neelesh A.; Marston, Jeremy; Chan, Derek Y C; Thoroddsen, Sigurdur T

2012-01-01

In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

The Power of Story in the ESL Classroom

Science.gov (United States)

Nicholas, Bonnie J.; Rossiter, Marian J.; Abbott, Marilyn L.

2011-01-01

Although considerable research has examined the use of literature in the second language (L2) classroom, there has been less investigation into the integration of learners' personal stories in the English as a second language (ESL) classroom. Following Wajnryb's (2003) categorizations of story as language learning, genre, and the creation of what…

DEPTH MEASUREMENT OF DISRUPTED LAYER ON SILICON WAFER SURFACE USING AUGER SPECTROSCOPY METHOD

Directory of Open Access Journals (Sweden)

V. A. Solodukha

2016-01-01

Full Text Available The paper proposes a method for depth measurement of a disrupted layer on silicon wafer surface which is based on application of Auger spectroscopy with the precision sputtering of surface silicon layers and registration of the Auger electron yield intensity. In order to measure the disrupted layer with the help of Auger spectroscopy it is necessary to determine dependence of the released Auger electron amount on sputtering time (profile and then the dependence is analyzed. Silicon amount in the disrupted layer is less than in the volume. While going deeper the disruptive layer is decreasing that corresponds to an increase of atom density in a single layer. The essence of the method lies in the fact the disruptive layer is removed by ion beam sputtering and detection of interface region is carried out with the help of registration of the Auger electron yield intensity from the sputtered surface up to the moment when it reaches the value which is equal to the Auger electron yield intensity for single-crystal silicon. While removing surface silicon layers the registration of the Auger electron yield intensity from silicon surface makes it possible to control efficiently a presence of the disrupted layer on the silicon wafer surface. In this case depth control locality is about 1.0 nm due to some peculiarities of Auger spectroscopy method. The Auger electron yield intensity is determined automatically while using Auger spectrometer and while removing the disrupted layer the intensity is gradually increasing. Depth of the disrupted layer is determined by measuring height of the step which has been formed as a result of removal of the disrupted layer from the silicon wafer surface. Auger spectroscopy methods ensures an efficient depth control surface disruptions at the manufacturing stages of silicon wafers and integrated circuits. The depth measurement range of disruptions constitutes 0.001–1.000 um.

A general analytical equation for phase diagrams of an N-layer ferroelectric thin film with two surface layers

Energy Technology Data Exchange (ETDEWEB)

Lu, Z X; Teng, B H; Rong, Y H; Lu, X H; Yang, X [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)], E-mail: phytbh@163.com

2010-03-15

Within the framework of effective-field theory with correlations, the phase diagrams of an N-layer ferroelectric thin film with two surface layers are studied by the differential operator technique based on the spin-1/2 transverse Ising model. A general analytical equation for the phase diagram of a ferroelectric thin film with arbitrary layer number as well as exchange interactions and transverse fields is derived, and then the effects of exchange interactions and transverse fields on phase diagrams are discussed for an arbitrary layer number N. Meanwhile, the crossover features, from the ferroelectric-dominant phase diagram (FPD) to the paraelectric-dominant phase diagram (PPD), for various parameters of an N-layer ferroelectric thin film with two surface layers are investigated. As a result, an N-independent common intersection point equation is obtained, and the three-dimensional curved surfaces for the crossover values are constructed. In comparison with the usual mean-field approximation, the differential operator technique with correlations reduces to some extent the ferroelectric features of a ferroelectric thin film.

Sensitivity to phonological context in L2 spelling: evidence from Russian ESL speakers

DEFF Research Database (Denmark)

Dich, Nadya

2010-01-01

The study attempts to investigate factors underlying the development of spellers’ sensitivity to phonological context in English. Native English speakers and Russian speakers of English as a second language (ESL) were tested on their ability to use information about the coda to predict the spelling...... on the information about the coda when spelling vowels in nonwords. In both native and non-native speakers, context sensitivity was predicted by English word spelling; in Russian ESL speakers this relationship was mediated by English proficiency. L1 spelling proficiency did not facilitate L2 context sensitivity...

Laminar boundary layer response to rotation of a finite diameter surface patch

International Nuclear Information System (INIS)

Klewicki, J.C.; Hill, R.B.

2003-01-01

The responses of the flat plate laminar boundary layer to perturbations generated by rotating a finite patch of the bounding surface are explored experimentally. The size of the surface patch was of the same order as the boundary layer thickness. The displacement thickness Reynolds number range of the boundary layers explored was 72-527. The rotation rates of the surface patch ranged from 2.14 to 62.8 s-1. Qualitative flow visualizations and quantitative molecular tagging velocimetry measurements revealed that rotation of a finite surface patch generates an asymmetric loop-like vortex. Significant features of this vortex include that, (i) the sign of the vorticity in the vortex head is opposite that of the boundary layer vorticity regardless of the sign of the input rotation, (ii) one leg of the vortex exhibits motion akin to solid body rotation while the other leg is best characterized as a spanwise shear layer, (iii) the vortex leg exhibiting near solid body rotation lifts more rapidly from the surface than the leg more like a shear layer, and (iv) the vortex leg exhibiting near solid body rotation always occurs on the side of the surface patch experiencing downstream motion. These asymmetries switch sides depending on the sign of the input rotation. The present results are interpreted and discussed relative to analytical solutions for infinite geometries. By way of analogy, plausible connections are drawn between the present results and the influences of wall normal vortices in turbulent boundary layer flows

Structural features of the adsorption layer of pentacene on the graphite surface and the PMMA/graphite hybrid surface

Science.gov (United States)

Fadeeva, A. I.; Gorbunov, V. A.; Litunenko, T. A.

2017-08-01

Using the molecular dynamics and the Monte Carlo methods, we have studied the structural features and growth mechanism of the pentacene film on graphite and polymethylmethacrylate /graphite surfaces. Monolayer capacity and molecular area, optimal angles between the pentacene molecules and graphite and PMMA/graphite surfaces as well as the characteristic angles between the neighboring pentacene molecules in the adsorption layer were estimated. It is shown that the orientation of the pentacene molecules in the film is determined by a number of factors, including the surface concentration of the molecules, relief of the surface, presence or absence of the polymer layer and its thickness. The pentacene molecules adsorbed on the graphite surface keep a horizontal position relative to the long axis at any surface coverage/thickness of the film. In the presence of the PMMA layer on the graphite, the increase of the number of pentacene molecules as well as the thickness of the PMMA layer induce the change of molecular orientation from predominantly horizontal to vertical one. The reason for such behavior is supposed to be the roughness of the PMMA surface.

Elastic layer under axisymmetric indentation and surface energy effects

Science.gov (United States)

Intarit, Pong-in; Senjuntichai, Teerapong; Rungamornrat, Jaroon

2018-04-01

In this paper, a continuum-based approach is adopted to investigate the contact problem of an elastic layer with finite thickness and rigid base subjected to axisymmetric indentation with the consideration of surface energy effects. A complete Gurtin-Murdoch surface elasticity is employed to consider the influence of surface stresses. The indentation problem of a rigid frictionless punch with arbitrary axisymmetric profiles is formulated by employing the displacement Green's functions, derived with the aid of Hankel integral transform technique. The problem is solved by assuming the contact pressure distribution in terms of a linear combination of admissible functions and undetermined coefficients. Those coefficients are then obtained by employing a collocation technique and an efficient numerical quadrature scheme. The accuracy of proposed solution technique is verified by comparing with existing solutions for rigid indentation on an elastic half-space. Selected numerical results for the indenters with flat-ended cylindrical and paraboloidal punch profiles are presented to portray the influence of surface energy effects on elastic fields of the finite layer. It is found that the presence of surface stresses renders the layer stiffer, and the size-dependent behavior of elastic fields is observed in the present solutions. In addition, the surface energy effects become more pronounced with smaller contact area; thus, the influence of surface energy cannot be ignored in the analysis of indentation problem especially when the indenter size is very small such as in the case of nanoindentation.

Double Charged Surface Layers in Lead Halide Perovskite Crystals

KAUST Repository

Sarmah, Smritakshi P.

2017-02-01

Understanding defect chemistry, particularly ion migration, and its significant effect on the surface’s optical and electronic properties is one of the major challenges impeding the development of hybrid perovskite-based devices. Here, using both experimental and theoretical approaches, we demonstrated that the surface layers of the perovskite crystals may acquire a high concentration of positively charged vacancies with the complementary negatively charged halide ions pushed to the surface. This charge separation near the surface generates an electric field that can induce an increase of optical band gap in the surface layers relative to the bulk. We found that the charge separation, electric field, and the amplitude of shift in the bandgap strongly depend on the halides and organic moieties of perovskite crystals. Our findings reveal the peculiarity of surface effects that are currently limiting the applications of perovskite crystals and more importantly explain their origins, thus enabling viable surface passivation strategies to remediate them.

Methods of improvement in hardness of composite surface layer on cast steel

Directory of Open Access Journals (Sweden)

J. Szajnar

2008-08-01

Full Text Available The paper presents a method of usable properties of surface layers improvement of cast carbon steel 200–450, by put directly in founding process a composite surface layer on the basis of Fe-Cr-C alloy and next its remelting with use of welding technology TIG – Tungsten Inert Gas. Technology of composite surface layer guarantee mainly increase in hardness and abrasive wear resistance of cast steel castings on machine elements. This technology can be competition for generally applied welding technology (surfacing by welding and thermal spraying. However the results of studies show, that is possible to connection of both methods founding and welding of surface hardening of cast steel castings. In range of experimental plan was made test castings with composite surface layer, which next were remelted with energy 0,8 and 1,6 kJ/cm. Usability for industrial applications of test castings was estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

Al2O3 dielectric layers on H-terminated diamond: Controlling surface conductivity

Science.gov (United States)

Yang, Yu; Koeck, Franz A.; Dutta, Maitreya; Wang, Xingye; Chowdhury, Srabanti; Nemanich, Robert J.

2017-10-01

This study investigates how the surface conductivity of H-terminated diamond can be preserved and stabilized by using a dielectric layer with an in situ post-deposition treatment. Thin layers of Al2O3 were grown by plasma enhanced atomic layer deposition (PEALD) on H-terminated undoped diamond (100) surfaces. The changes of the hole accumulation layer were monitored by correlating the binding energy of the diamond C 1s core level with electrical measurements. The initial PEALD of 1 nm Al2O3 resulted in an increase of the C 1s core level binding energy consistent with a reduction of the surface hole accumulation and a reduction of the surface conductivity. A hydrogen plasma step restored the C 1s binding energy to the value of the conductive surface, and the resistance of the diamond surface was found to be within the range for surface transfer doping. Further, the PEALD growth did not appear to degrade the surface conductive layer according to the position of the C 1s core level and electrical measurements. This work provides insight into the approaches to establish and control the two-dimensional hole-accumulation layer of the H-terminated diamond and improve the stability and performance of H-terminated diamond electronic devices.

X-ray evaluation of residual stress distributions within surface machined layer generated by surface machining and sequential welding

International Nuclear Information System (INIS)

Taniguchi, Yuu; Okano, Shigetaka; Mochizuki, Masahito

2017-01-01

The excessive tensile residual stress generated by welding after surface machining may be an important factor to cause stress corrosion cracking (SCC) in nuclear power plants. Therefore we need to understand and control the residual stress distribution appropriately. In this study, residual stress distributions within surface machined layer generated by surface machining and sequential welding were evaluated by X-ray diffraction method. Depth directional distributions were also investigated by electrolytic polishing. In addition, to consider the effect of work hardened layer on the residual stress distributions, we also measured full width at half maximum (FWHM) obtained from X-ray diffraction. Testing material was a low-carbon austenitic stainless steel type SUS316L. Test specimens were prepared by surface machining with different cutting conditions. Then, bead-on-plate welding under the same welding condition was carried out on the test specimens with different surface machined layer. As a result, the tensile residual stress generated by surface machining increased with increasing cutting speed and showed nearly uniform distributions on the surface. Furthermore, the tensile residual stress drastically decreased with increasing measurement depth within surface machined layer. Then, the residual stress approached 0 MPa after the compressive value showed. FWHM also decreased drastically with increasing measurement depth and almost constant value from a certain depth, which was almost equal regardless of the machining condition, within surface machined layer in all specimens. After welding, the transverse distribution of the longitudinal residual stress varied in the area apart from the weld center according to machining conditions and had a maximum value in heat affected zone. The magnitude of the maximum residual stress was almost equal regardless of the machining condition and decreased with increasing measurement depth within surface machined layer. Finally, the

Stability conditions of stationary rupture of liquid layers on an immiscible fluid surface

Energy Technology Data Exchange (ETDEWEB)

Viviani, A. [Seconda Univ. di Napoli, Aversa (Italy). Facolta di Ingegneria; Kostarev, K.; Shmyrov, A.; Zuev, A. [Inst. of Continuous Media Mechanics, Perm (Russian Federation)

2009-07-01

The stationary equilibrium shape of a 3-phase liquids-gas system was investigated. The system consisted of a horizontal liquid layer with an upper free boundary placed on the immiscible fluid interface. The study investigated the stability conditions of rupture of the liquid layer surface. The dependence of rupture parameters on the experimental cuvette diameter and layer thickness was investigated, as well as the difference in the values of surface tension of the examined fluids. The 2-layer system of horizontal fluid layers was formed in a glass cylindrical cuvette. The liquid substrate was tetrachloride carbon (CCI{sub 4}), while upper layers included water, glycerine, ethyleneglycol, and aqueous solutions of 1,4-butanediol C{sub 4}H{sub 10}O{sub 2} and isopropanol C{sub 3H8L}. Initially, the surface of the substrate fluid was overlaid with a horizontal liquid layer. The rupture was formed by subjecting the layer surface to short-time actions of a narrow directional air jet. After rupture formation, the layer thickness increased gradually. The measurements demonstrated that the rupture diameter depends on the initial thickness of the upper layer as well as the diameter of the cuvette, and the difference in the values of the surface tension of the examined fluids. Analysis of the experimental relationships indicated that the critical thickness of the breaking layer is a constant value for any specific pairs of fluids. 4 refs., 7 figs.

Surface Phenomena During Plasma-Assisted Atomic Layer Etching of SiO2.

Science.gov (United States)

Gasvoda, Ryan J; van de Steeg, Alex W; Bhowmick, Ranadeep; Hudson, Eric A; Agarwal, Sumit

2017-09-13

Surface phenomena during atomic layer etching (ALE) of SiO 2 were studied during sequential half-cycles of plasma-assisted fluorocarbon (CF x ) film deposition and Ar plasma activation of the CF x film using in situ surface infrared spectroscopy and ellipsometry. Infrared spectra of the surface after the CF x deposition half-cycle from a C 4 F 8 /Ar plasma show that an atomically thin mixing layer is formed between the deposited CF x layer and the underlying SiO 2 film. Etching during the Ar plasma cycle is activated by Ar + bombardment of the CF x layer, which results in the simultaneous removal of surface CF x and the underlying SiO 2 film. The interfacial mixing layer in ALE is atomically thin due to the low ion energy during CF x deposition, which combined with an ultrathin CF x layer ensures an etch rate of a few monolayers per cycle. In situ ellipsometry shows that for a ∼4 Å thick CF x film, ∼3-4 Å of SiO 2 was etched per cycle. However, during the Ar plasma half-cycle, etching proceeds beyond complete removal of the surface CF x layer as F-containing radicals are slowly released into the plasma from the reactor walls. Buildup of CF x on reactor walls leads to a gradual increase in the etch per cycle.

Comparative Difficulties with Non-Scientific General Vocabulary and Scientific/Medical Terminology in English as a Second Language (ESL) Medical Students.

Science.gov (United States)

Heming, Thomas A; Nandagopal, Shobha

2012-11-01

Medical education requires student comprehension of both technical (scientific/medical) and non-technical (general) vocabulary. Our experience with "English as a second language" (ESL) Arab students suggested they often have problems comprehending scientific statements because of weaknesses in their understanding of non-scientific vocabulary. This study aimed to determine whether ESL students have difficulties with general vocabulary that could hinder their understanding of scientific/medical texts. A survey containing English text was given to ESL students in the premedical years of an English-medium medical school in an Arabic country. The survey consisted of sample questions from the Medical College Admission Test (USA). Students were instructed to identify all unknown words in the text. ESL students commenced premedical studies with substantial deficiencies in English vocabulary. Students from English-medium secondary schools had a selective deficiency in scientific/medical terminology which disappeared with time. Students from Arabic-medium secondary schools had equal difficulty with general and scientific/medical vocabulary. Deficiencies in both areas diminished with time but remained even after three years of English-medium higher education. Typically, when teaching technical subjects to ESL students, attention is focused on subject-unique vocabulary and associated modifiers. This study highlights that ESL students also face difficulties with the general vocabulary used to construct statements employing technical words. Such students would benefit from increases in general vocabulary knowledge.

A novel surface cleaning method for chemical removal of fouling lead layer from chromium surfaces

International Nuclear Information System (INIS)

Gholivand, Kh.; Khosravi, M.; Hosseini, S.G.; Fathollahi, M.

2010-01-01

Most products especially metallic surfaces require cleaning treatment to remove surface contaminations that remain after processing or usage. Lead fouling is a general problem which arises from lead fouling on the chromium surfaces of bores and other interior parts of systems which have interaction with metallic lead in high temperatures and pressures. In this study, a novel chemical solution was introduced as a cleaner reagent for removing metallic lead pollution, as a fouling metal, from chromium surfaces. The cleaner aqueous solution contains hydrogen peroxide (H 2 O 2 ) as oxidizing agent of lead layer on the chromium surface and acetic acid (CH 3 COOH) as chelating agent of lead ions. The effect of some experimental parameters such as acetic acid concentration, hydrogen peroxide concentration and temperature of the cleaner solution during the operation on the efficiency of lead cleaning procedure was investigated. The results of scanning electron microscopy (SEM) showed that using this procedure, the lead pollution layer could be completely removed from real chromium surfaces without corrosion of the original surface. Finally, the optimum conditions for the complete and fast removing of lead pollution layer from chromium surfaces were proposed. The experimental results showed that at the optimum condition (acetic acid concentration 28% (V/V), hydrogen peroxide 8% (V/V) and temperature 35 deg. C), only 15-min time is needed for complete removal of 3 g fouling lead from a chromium surface.

Characterization of SCC crack tips and surface oxide layers in alloy 600

Energy Technology Data Exchange (ETDEWEB)

Fujii, Katsuhiko; Fukuya, Koji [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2002-09-01

In order to investigate the mechanism of primary water stress corrosion cracking (SCC), direct observation of microstructures of SCC crack tips and surface oxide layers in alloy 600 were carried out. A focused-ion beam (FIB) micro-processing technique was applied to prepare electron transparent foils including the crack tip and the surface oxide layer without any damage to those microstructures. Transmission electron microscopy and analysis were used to characterize the crack tips and surface oxide layers. Cr-rich oxides and a metal-Ni phase were identified in the crack tips and grain boundaries ahead of the crack tips independent of dissolved hydrogen concentrations. >From the fact that the Cr-rich oxides and metal-Ni phase were observed in the inner surface oxide layer, the same oxidation mechanism as the surface is proposed for the crack tip region and internal oxidation accompanying selective Cr oxidation is suggested as the mechanism. (author)

Optical transparency of graphene layers grown on metal surfaces

International Nuclear Information System (INIS)

Rut’kov, E. V.; Lavrovskaya, N. P.; Sheshenya, E. S.; Gall, N. R.

2017-01-01

It is shown that, in contradiction with the fundamental results obtained for free graphene, graphene films grown on the Rh(111) surface to thicknesses from one to ~(12–15) single layers do not absorb visible electromagnetic radiation emitted from the surface and influence neither the brightness nor true temperature of the sample. At larger thicknesses, such absorption occurs. This effect is observed for the surfaces of other metals, specifically, Pt(111), Re(1010), and Ni(111) and, thus, can be considered as being universal. It is thought that the effect is due to changes in the electronic properties of thin graphene layers because of electron transfer between graphene and the metal substrate.

Optical transparency of graphene layers grown on metal surfaces

Energy Technology Data Exchange (ETDEWEB)

Rut’kov, E. V. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Lavrovskaya, N. P. [State University of Aerospace Instrumentation (Russian Federation); Sheshenya, E. S., E-mail: sheshenayket@gmail.ru; Gall, N. R. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

2017-04-15

It is shown that, in contradiction with the fundamental results obtained for free graphene, graphene films grown on the Rh(111) surface to thicknesses from one to ~(12–15) single layers do not absorb visible electromagnetic radiation emitted from the surface and influence neither the brightness nor true temperature of the sample. At larger thicknesses, such absorption occurs. This effect is observed for the surfaces of other metals, specifically, Pt(111), Re(1010), and Ni(111) and, thus, can be considered as being universal. It is thought that the effect is due to changes in the electronic properties of thin graphene layers because of electron transfer between graphene and the metal substrate.

The effects of linguistic modification on ESL students' comprehension of nursing course test items.

Science.gov (United States)

Bosher, Susan; Bowles, Melissa

2008-01-01

Recent research has indicated that language may be a source of construct-irrelevant variance for non-native speakers of English, or English as a second language (ESL) students, when they take exams. As a result, exams may not accurately measure knowledge of nursing content. One accommodation often used to level the playing field for ESL students is linguistic modification, a process by which the reading load of test items is reduced while the content and integrity of the item are maintained. Research on the effects of linguistic modification has been conducted on examinees in the K-12 population, but is just beginning in other areas. This study describes the collaborative process by which items from a pathophysiology exam were linguistically modified and subsequently evaluated for comprehensibility by ESL students. Findings indicate that in a majority of cases, modification improved examinees' comprehension of test items. Implications for test item writing and future research are discussed.

EFL/ESL Textbook Selection in Korea and East Asia - Relevant Issues and Literature Review

Science.gov (United States)

Meurant, Robert C.

EFL/ESL departments periodically face the problem of textbook selection. Cogent issues are that non-native speakers will use L2 English mainly to communicate with other non-native English speakers, so an American accent is becoming less important. L2 English will mainly be used in computer-mediated communication, hence the importance of L2 Digital Literacy. The convergence of Information Communication Technologies is radically impacting Second Language Acquisition, which is integrating web-hosted Assessment and Learning Management Systems. EFL/ESL textbooks need to be compatible with blended learning, prepare students for a globalized world, and foster autonomous learning. I summarize five papers on EFL/ESL textbook evaluation and selection, and include relevant material for adaptation. Textbooks are major sources of contact with the target language, so selection is an important decision. Educators need to be systematic and objective in their approach, adopting a selection process that is open, transparent, accountable, participatory, informed and rigorous.

Evidence of a Transition Layer between the Free Surface and the Bulk

KAUST Repository

Ogieglo, Wojciech; Tempelman, Kristianne; Napolitano, Simone; Benes, Nieck E.

2018-01-01

The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

Evidence of a Transition Layer between the Free Surface and the Bulk

KAUST Repository

Ogieglo, Wojciech

2018-02-21

The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

Evidence of a Transition Layer between the Free Surface and the Bulk.

Science.gov (United States)

Ogieglo, Wojciech; Tempelman, Kristianne; Napolitano, Simone; Benes, Nieck E

2018-03-15

The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

Adventure in a new language: what a first generation Canadian immigrant’s narrative holds for ESL teachers

Directory of Open Access Journals (Sweden)

Fang Xing

2016-09-01

Full Text Available This paper explored the value of learner’s stories for ESL (English as a Second Language teachers’ teaching and research through a narrative inquiry of the lived English learning experience of a first generation Canadian immigrant. It first reviewed the concept of narrative and the significance of launching narrative inquiry. Then, it presented an interview conducted with the Canadian immigrant as a model of narrative inquiry. Themes of the narrative interview were found to resonate with theoretical issues of SLE (Second Language Education, ESL and SLA (Second Language Acquisition. Considering the themes and the entire interviewing process, this paper closed with a discussion of the benefits of narrative inquiry for ESL teachers’ teaching and research.

Arab ESL Secondary School Students' Spelling Errors

Science.gov (United States)

Al-Sobhi, Bandar Mohammad Saeed; Rashid, Sabariah Md; Abdullah, Ain Nadzimah; Darmi, Ramiza

2017-01-01

English spelling has always been described by many language researchers and teachers as a daunting task especially for learners whose first language is not English. Accordingly, Arab ESL learners commit serious errors when they spell out English words. The primary objective of this paper is to determine the types as well as the causes of spelling…

Streams and magnetic fields in surface layers of Ap-stars

International Nuclear Information System (INIS)

Dolginov, A.Z.; Urpin, V.A.

1978-01-01

Magnetic field generation of Ap-stars is considered. It is shown that in the surface layers of Ap-stars inhomogeneity of chemical composition produces a strong magnetic field. Velocities of possible circulation of stellar matter are estimated. It is shown that circulation does not prevent the process of the magnetic field generation. It needs the order of million years, for arranging the stationary magnetic field in surface layers

A Review on Studies of Phrasal Verb Constructions in ESL Context

Directory of Open Access Journals (Sweden)

Maryam Jahedi

2015-02-01

Full Text Available This paper aims to give an overview of studies on phrasal verbs in three decades to present the theoretical and methodological issues, as well as the findings of research. Moreover, this review reveals the developments and paradigm shifts occurred in this area. Previous studies have shown that the research findings have not been incorporated into classroom activities and English Language Teaching (ELT materials. The paper claims that the number of research on the use of phrasal verbs in ESL textbooks is limited and, therefore, further research is needed to examine how phrasal verbs are treated in textbooks in order to help ELT materials developers to present these items more effectively based on research findings. Keywords: Corpus-based studies, ESL learner, Phrasal verbs

Thermocouple Rakes for Measuring Boundary Layer Flows Extremely Close to Surface

Science.gov (United States)

Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Blaha, Charles A.

2001-01-01

Of vital interest to aerodynamic researchers is precise knowledge of the flow velocity profile next to the surface. This information is needed for turbulence model development and the calculation of viscous shear force. Though many instruments can determine the flow velocity profile near the surface, none of them can make measurements closer than approximately 0.01 in. from the surface. The thermocouple boundary-layer rake can measure much closer to the surface than conventional instruments can, such as a total pressure boundary layer rake, hot wire, or hot film. By embedding the sensors (thermocouples) in the region where the velocity is equivalent to the velocity ahead of a constant thickness strut, the boundary-layer flow profile can be obtained. The present device fabricated at the NASA Glenn Research Center microsystem clean room has a heater made of platinum and thermocouples made of platinum and gold. Equal numbers of thermocouples are placed both upstream and downstream of the heater, so that the voltage generated by each pair at the same distance from the surface is indicative of the difference in temperature between the upstream and downstream thermocouple locations. This voltage differential is a function of the flow velocity, and like the conventional total pressure rake, it can provide the velocity profile. In order to measure flow extremely close to the surface, the strut is made of fused quartz with extremely low heat conductivity. A large size thermocouple boundary layer rake is shown in the following photo. The latest medium size sensors already provide smooth velocity profiles well into the boundary layer, as close as 0.0025 in. from the surface. This is about 4 times closer to the surface than the previously used total pressure rakes. This device also has the advantage of providing the flow profile of separated flow and also it is possible to measure simultaneous turbulence levels within the boundary layer.

Educating Bilingual/ESL Teachers in a Language/Culture Exchange Field School: A Collaborative Model in Teacher Education.

Science.gov (United States)

Guadarrama, Irma N.

This paper describes a program that brings bilingual and English-as-a-Second-Language (ESL) teachers from the United States to a Mexican ESL school to teach in the Tetiz (Yucatan, Mexico) field school and in exchange, learn Mayan language and culture. The theoretical base for the project is drawn from the work of major theorists in second language…

Measurements of surface layer of the articular cartilage using microscopic techniques

International Nuclear Information System (INIS)

Ryniewicz, A. M; Ryniewicz, W.; Ryniewicz, A.; Gaska, A.

2010-01-01

The articular cartilage is the structure that directly cooperates tribologically in biobearing. It belongs to the connective tissues and in the joints it assumes two basic forms: hyaline cartilage that builds joint surfaces and fibrocartilage which may create joint surfaces. From this fibrocartilage are built semilunar cartilage and joint disc are built as well. The research of articular cartilage have been done in macro, micro and nano scale. In all these measurement areas characteristic features occur which can identify biobearing tribology. The aim of the research was the identification of surface layer of articular cartilage by means of scanning electron microscopy (SEM) and atom force microscopy (AFM) and the analysis of topography of these layers. The material used in the research of surface layer was the animal articular cartilage: hyaline cartilage and fibrocartilage.

Measurements of surface layer of the articular cartilage using microscopic techniques

Science.gov (United States)

Ryniewicz, A. M.; Ryniewicz, A.; Ryniewicz, W.; Gaska, A.

2010-07-01

The articular cartilage is the structure that directly cooperates tribologically in biobearing. It belongs to the connective tissues and in the joints it assumes two basic forms: hyaline cartilage that builds joint surfaces and fibrocartilage which may create joint surfaces. From this fibrocartilage are built semilunar cartilage and joint disc are built as well. The research of articular cartilage have been done in macro, micro and nano scale. In all these measurement areas characteristic features occur which can identify biobearing tribology. The aim of the research was the identification of surface layer of articular cartilage by means of scanning electron microscopy (SEM) and atom force microscopy (AFM) and the analysis of topography of these layers. The material used in the research of surface layer was the animal articular cartilage: hyaline cartilage and fibrocartilage.

Strengthening of the RAFMS RUSFER-EK181 through nano structuring surface layers

Energy Technology Data Exchange (ETDEWEB)

Panin, A.; Melnikova, E.A. [Tomsk State Univ., lnstitute of Strength Physics and Materials Science, SB, RAS (Russian Federation); Chernov, V.M. [Bochvar Institute of Inorganic Materials, Moscow (Russian Federation); Leontieva-Smirnova, M.V. [A.A. Bochvar Research Institute of Inorganic Materials, Moscow (Russian Federation)

2007-07-01

Full text of publication follows: Surface nano-structuring increases yield point and strength of the reduced activation ferritic-martensitic steel (RAFMS ) RUSREF - EK181. Ultrasonic impact treatment was used to produce a nano-structure within the surface layers of the specimens. Using scanning tunnelling microscope reveals a new mechanism of mesoscale-level plastic deformation of nano-structured surface layers of the RAFMS RUSREF - EK181 as doubled spirals of localised-plastic deformation meso-bands. A linear dependence of their sizes on thickness of strengthened layer was obtained. The effect of localised deformation meso-bands on macro-mechanical properties of a material was demonstrated. A certain combination of thermal and mechanical treatment as well as optimum proportion of nano-structured surface layer thickness to thickness of a whole specimen are necessary to achieve maximum strength values. Tests performed at high temperatures in the range from 20 to 700 deg. C shows efficiency of the surface hardening of the RAFMS RUSREF - EK181. The effect of nano-structured surface layer on the character of plastic deformation and mechanical properties of the RAFMS RUSREF - EK181 was considered in the framework of a multilevel model in which loss of shear stability and generation of structural defects occur self-consistently at various scale levels such as nano-, micro-, meso-, and macro-Chessboard like distribution of stresses and misfit deformations was theoretical and experimentally shown to appear at the 'nano-structured surface layer - bulk of material' interface. Zones of compressive normal stresses alternates with zones of tensile normal stresses as on a chessboard. Plastic shear can generate only within local zones of tensile normal stresses. Critical meso-volume of non-equilibrium states required for local structure-phase transformation can be formed within these zones. Whereas within the zones of compressive normal stresses acting from both

Study on dynamic deformation synchronized measurement technology of double-layer liquid surfaces

Science.gov (United States)

Tang, Huiying; Dong, Huimin; Liu, Zhanwei

2017-11-01

Accurate measurement of the dynamic deformation of double-layer liquid surfaces plays an important role in many fields, such as fluid mechanics, biomechanics, petrochemical industry and aerospace engineering. It is difficult to measure dynamic deformation of double-layer liquid surfaces synchronously for traditional methods. In this paper, a novel and effective method for full-field static and dynamic deformation measurement of double-layer liquid surfaces has been developed, that is wavefront distortion of double-wavelength transmission light with geometric phase analysis (GPA) method. Double wavelength lattice patterns used here are produced by two techniques, one is by double wavelength laser, and the other is by liquid crystal display (LCD). The techniques combine the characteristics such as high transparency, low reflectivity and fluidity of liquid. Two color lattice patterns produced by laser and LCD were adjusted at a certain angle through the tested double-layer liquid surfaces simultaneously. On the basis of the refractive indexes difference of two transmitted lights, the double-layer liquid surfaces were decoupled with GPA method. Combined with the derived relationship between phase variation of transmission-lattice patterns and out-of plane heights of two surfaces, as well as considering the height curves of the liquid level, the double-layer liquid surfaces can be reconstructed successfully. Compared with the traditional measurement method, the developed method not only has the common advantages of the optical measurement methods, such as high-precision, full-field and non-contact, but also simple, low cost and easy to set up.

Improvement of Surface Layer Characteristics by Shot Lining

Science.gov (United States)

Harada, Yasunori

In the present study, lining of the metal with foils using shot peening was investigated to improve the surface layer characteristics. In the shot peening experiment, the foils set on the metal are pelted with hard particles traveling at a high velocity. The foils are bonded to the metal surface due to plastic deformation induced by the collision of the particles. The foils and the metal are heated to heighten the bondability because of the reduction of flow stress. Lining the metal with the hard powder sandwiched between two aluminum foil sheets was also attempted. In this experiment, a centrifugal shot peening machine wite an electrical heater was employed. The metals are commercially aluminium alloys and magnesium alloys, and the foils are commercially aluminum, titanium and nickel. The effects of shot speed and the heating temperature on the bondability were examined. Wear resistance was also evaluated by grinding. The foils were successfully bonded to the metal surface. It was found that the present method is effective in improving of surface layer characteristics.

ESL-speaking immigrant women's disillusions: voices of health care in Canada: an ethnodrama.

Science.gov (United States)

Nimmon, Laura E

2007-04-01

This article describes a research project that investigated whether language barriers play a part in immigrant women's health decreasing when they move to Canada. The findings are then represented in the form of an ethnodrama entitled "ESL-Speaking Immigrant Women's Disillusions: Voices of Health Care in Canada." I suggest that the play is catalytic because it encourages target audiences to empathize with the silenced voices of ESL-speaking immigrant women who live in Canada. I then conclude with a reflection about the potential that the genre of ethnodrama has for social change through its reflexive and critical nature.

Perspectives: Using Critical Incidents to Understand ESL Student Satisfaction

Science.gov (United States)

Walker, John

2015-01-01

In a marketized environment, ESL providers, in common with other postcompulsory educational institutions, canvass student satisfaction with their services. While the predominant method is likely to be based on tick-box questionnaires using Likert scales that measure degrees of satisfaction, qualitative methodology is an option when rich data is…

Effect of surface wave propagation in a four-layered oceanic crust model

Science.gov (United States)

Paul, Pasupati; Kundu, Santimoy; Mandal, Dinbandhu

2017-12-01

Dispersion of Rayleigh type surface wave propagation has been discussed in four-layered oceanic crust. It includes a sandy layer over a crystalline elastic half-space and over it there are two more layers—on the top inhomogeneous liquid layer and under it a liquid-saturated porous layer. Frequency equation is obtained in the form of determinant. The effects of the width of different layers as well as the inhomogeneity of liquid layer, sandiness of sandy layer on surface waves are depicted and shown graphically by considering all possible case of the particular model. Some special cases have been deduced, few special cases give the dispersion equation of Scholte wave and Stoneley wave, some of which have already been discussed elsewhere.

Estudio comparativo de los eslóganes electorales y comerciales: el caso de las elecciones generales españolas de 2008

Directory of Open Access Journals (Sweden)

Manuel Garrido-Lora

2013-01-01

Full Text Available Este artículo presenta un estudio comparativo entre los eslóganes políticos y los eslóganes comerciales utilizados en la comunicación publicitaria de España. La investigación, sin precedentes en el ámbito español, pretende descubrir las diferencias y semejanzas estratégicas, conceptuales y formales entre ambos tipos de eslóganes. De este modo, los resultados de un estudio previo del autor en el ámbito de la comunicación comercial se comparan con el análisis de los eslóganes empleados por los principales partidos políticos españoles durante las elecciones generales de marzo de 2008. Las conclusiones muestran interesantes cualidades diferenciales de los eslóganes políticos que deben ser consideradas por los investigadores y profesionales de la comunicación publicitaria: brevedad, densidad semántica, retórica moderada, baja perdurabilidad o uso estratégico son algunas de ellas.

Nucleation and Early Stages of Layer-by-Layer Growth of Metal Organic Frameworks on Surfaces

Science.gov (United States)

2015-01-01

High resolution atomic force microscopy (AFM) is used to resolve the evolution of crystallites of a metal organic framework (HKUST-1) grown on Au(111) using a liquid-phase layer-by-layer methodology. The nucleation and faceting of individual crystallites is followed by repeatedly imaging the same submicron region after each cycle of growth and we find that the growing surface is terminated by {111} facets leading to the formation of pyramidal nanostructures for [100] oriented crystallites, and triangular [111] islands with typical lateral dimensions of tens of nanometres. AFM images reveal that crystallites can grow by 5–10 layers in each cycle. The growth rate depends on crystallographic orientation and the morphology of the gold substrate, and we demonstrate that under these conditions the growth is nanocrystalline with a morphology determined by the minimum energy surface. PMID:26709359

Surface role in reorientation of internal layers of molybdenum single crystal during rolling

International Nuclear Information System (INIS)

Antsiforov, P.N.; Gorordetskij, S.D.; Markashova, A.I.; Martynenko, S.I.

1991-01-01

Structure, orientations and chemical composition of surface and internal layers of molybdenum rolled monocrystals are studied using electron microscopy, X-ray and Auger-analyses. Model of reorientation allowing to determine relation of deformation mechanism localized in surface layer with reorientation of internal layers, is described to explain the results

Fluorocarbon based atomic layer etching of Si{sub 3}N{sub 4} and etching selectivity of SiO{sub 2} over Si{sub 3}N{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Li, Chen [Department of Physics, and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Metzler, Dominik; Oehrlein, Gottlieb S., E-mail: oehrlein@umd.edu [Department of Materials Science and Engineering, and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Lai, Chiukin Steven; Hudson, Eric A. [Lam Research Corporation, 4400 Cushing Parkway, Fremont, California 94538 (United States)

2016-07-15

Angstrom-level plasma etching precision is required for semiconductor manufacturing of sub-10 nm critical dimension features. Atomic layer etching (ALE), achieved by a series of self-limited cycles, can precisely control etching depths by limiting the amount of chemical reactant available at the surface. Recently, SiO{sub 2} ALE has been achieved by deposition of a thin (several Angstroms) reactive fluorocarbon (FC) layer on the material surface using controlled FC precursor flow and subsequent low energy Ar{sup +} ion bombardment in a cyclic fashion. Low energy ion bombardment is used to remove the FC layer along with a limited amount of SiO{sub 2} from the surface. In the present article, the authors describe controlled etching of Si{sub 3}N{sub 4} and SiO{sub 2} layers of one to several Angstroms using this cyclic ALE approach. Si{sub 3}N{sub 4} etching and etching selectivity of SiO{sub 2} over Si{sub 3}N{sub 4} were studied and evaluated with regard to the dependence on maximum ion energy, etching step length (ESL), FC surface coverage, and precursor selection. Surface chemistries of Si{sub 3}N{sub 4} were investigated by x-ray photoelectron spectroscopy (XPS) after vacuum transfer at each stage of the ALE process. Since Si{sub 3}N{sub 4} has a lower physical sputtering energy threshold than SiO{sub 2}, Si{sub 3}N{sub 4} physical sputtering can take place after removal of chemical etchant at the end of each cycle for relatively high ion energies. Si{sub 3}N{sub 4} to SiO{sub 2} ALE etching selectivity was observed for these FC depleted conditions. By optimization of the ALE process parameters, e.g., low ion energies, short ESLs, and/or high FC film deposition per cycle, highly selective SiO{sub 2} to Si{sub 3}N{sub 4} etching can be achieved for FC accumulation conditions, where FC can be selectively accumulated on Si{sub 3}N{sub 4} surfaces. This highly selective etching is explained by a lower carbon consumption of Si{sub 3}N{sub 4} as compared to Si

Flipped Learning for ESL Writing in a Sudanese School

Science.gov (United States)

Abdelrahman, Limia Ali Mohamed; DeWitt, Dorothy; Alias, Norlidah; Rahman, Mohd Nazri Abdul

2017-01-01

Sudanese students seem to lack proficiency in writing English. In addition, teachers continue to use traditional, teacher-centered methods in teaching English as a second language (ESL). The flipped learning (FL) approach where video lectures are assigned as online homework before class, followed by learning activities during class, might be able…

Teacher's Approaches in Teaching Literature: Observations of ESL Classroom

Science.gov (United States)

Mustakim, Siti Salina; Mustapha, Ramlee; Lebar, Othman

2014-01-01

This study aimed to identify the approaches employed by teachers in teaching Contemporary Children's Literature Program to upper primary school. Using classroom observations and interview as research instruments, this paper evaluates the approaches of five ESL teachers teaching Year 5 students and examines the various challenges faced by them in…

Body surface adaptations to boundary-layer dynamics

NARCIS (Netherlands)

Videler, J.J.

1995-01-01

Evolutionary processes have adapted nektonic animals to interact efficiently with the water that surrounds them. Not all these adaptations serve the same purpose. This paper concentrates on reduction of drag due to friction in the boundary layer close to the body surface. Mucus, compliant skins,

A scanning fluid dynamic gauging technique for probing surface layers

International Nuclear Information System (INIS)

Gordon, Patrick W; Chew, Y M John; Wilson, D Ian; Brooker, Anju D M; York, David W

2010-01-01

Fluid dynamic gauging (FDG) is a technique for measuring the thickness of soft solid deposit layers immersed in a liquid environment, in situ and in real time. This paper details the performance of a novel automated, scanning FDG probe (sFDG) which allows the thickness of a sample layer to be monitored at several points during an experiment, with a resolution of ±5 µm. Its application is demonstrated using layers of gelatine, polyvinyl alcohol (PVA) and baked tomato purée deposits. Swelling kinetics, as well as deformation behaviour—based on knowledge of the stresses imposed on the surface by the gauging flow—can be determined at several points, affording improved experimental data. The use of FDG as a surface scanning technique, operating as a fluid mechanical analogue of atomic force microscopy on a millimetre length scale, is also demonstrated. The measurement relies only on the flow behaviour, and is thus suitable for use in opaque fluids, does not contact the surface itself and does not rely on any specific physical properties of the surface, provided it is locally stiff

Three Empowering Curricular Innovations for Service-Learning in ESL Programs

Science.gov (United States)

Perren, James; Grove, Nuray; Thornton, Julie

2013-01-01

This article describes three service-learning projects implemented in three different ESL programs in the United States. Each description includes typical course goals, service-learning assignments, reflection activities, student learning outcomes, and pedagogical challenges. The first project was developing digital literacy through…

Surface-Layer (S-Layer) Proteins Sap and EA1 Govern the Binding of the S-Layer-Associated Protein BslO at the Cell Septa of Bacillus anthracis

Science.gov (United States)

Kern, Valerie J.; Kern, Justin W.; Theriot, Julie A.; Schneewind, Olaf

2012-01-01

The Gram-positive pathogen Bacillus anthracis contains 24 genes whose products harbor the structurally conserved surface-layer (S-layer) homology (SLH) domain. Proteins endowed with the SLH domain associate with the secondary cell wall polysaccharide (SCWP) following secretion. Two such proteins, Sap and EA1, have the unique ability to self-assemble into a paracrystalline layer on the surface of bacilli and form S layers. Other SLH domain proteins can also be found within the S layer and have been designated Bacillus S-layer-associated protein (BSLs). While both S-layer proteins and BSLs bind the same SCWP, their deposition on the cell surface is not random. For example, BslO is targeted to septal peptidoglycan zones, where it catalyzes the separation of daughter cells. Here we show that an insertional lesion in the sap structural gene results in elongated chains of bacilli, as observed with a bslO mutant. The chain length of the sap mutant can be reduced by the addition of purified BslO in the culture medium. This complementation in trans can be explained by an increased deposition of BslO onto the surface of sap mutant bacilli that extends beyond chain septa. Using fluorescence microscopy, we observed that the Sap S layer does not overlap the EA1 S layer and slowly yields to the EA1 S layer in a growth-phase-dependent manner. Although present all over bacilli, Sap S-layer patches are not observed at septa. Thus, we propose that the dynamic Sap/EA1 S-layer coverage of the envelope restricts the deposition of BslO to the SCWP at septal rings. PMID:22609927

Memory strategies and ESL vocabulary acquisition

Directory of Open Access Journals (Sweden)

Carisma Dreyer

2013-02-01

Full Text Available This article compares the effectiveness of three learning strategies (memory strategies for ESL vocabulary acquisition. Four intact ESL classes were divided into one control group and three treatment groups (keyword, semantic, and keyword-semantic. These Afrikaans-speaking standard 6 pupils then received 4 days of instruction. Both multiplechoice and cued-recall instruments were used to measure effects both 1 day and 9 days after instruction. The results indicated that for both the multiple-choice and cued-recall tests the combined keyword-semantic strategy differed statistically Significantly as well as practically significantly from the keyword method. The results, therefore, suggest that the combined keyword-semantic strategy increased retention above the other strategies. Hierdie artikel vergelyk die effektiwiteit van drie taalleerstrategiee (geheue strategiee vir die aanleer van woordeskat met mekaar. Vier intak Engels tweedetaal klasse is verdeel in een kontrole groep en drie eksperimentele groepe (sleutelwoord, semantiese en 'n kombinasie van die sleutelwoord-semantiese strategiee. 'n Groep Afrikaanssprekende standerd ses leerlinge het vir 'n tydperk van vier dae onderrig in elk van bogenoemde strategiee ontvang. Multikeuse en "cued-recall" instrumente is gebruik om die effek van onderrig beide een dag en nege dae na eksperimentering te bepaal. Die resultate het aangetoon dat die gekombineerde sleutelwoord-semantiese strategie statisties betekenisvol sowel as prakties betekenisvol van die sleutelwoord strategie en die kontrole groep verskil het. Dit wil dus voorkom asof die gekombineerde sleutelwoord-semantiese strategie die mees belowende strategie is ten opsigte van die retensie van woordeskat.

Prospective ESL/EFL Teachers’ Perceptions towards Writing Poetry in a Second Language: Difficulty, Value, Emotion, and Attitude

Directory of Open Access Journals (Sweden)

Fang-Yu Liao

2018-03-01

Full Text Available The study aims to explore how 18 M.A. TESOL students, who are prospective or experienced ESL/EFL teachers, perceive poetry writing in a second language. A qualitative interview-based design was utilized. Following Iida’s (2012a analytical framework in examining EFL students’ perceptions toward writing haiku in English, this current study investigates 18 prospective ESL/EFL teachers’ perspectives through the lens of difficulty, value, emotion, and attitude. In order to validate the coding of the interviews, the intraclass correlation coefficient (ICC test was computed among three interview coders including the primary researcher, which yields a great agreement rate at .86. The results indicate that while these prospective ESL/EFL teachers understand writing poetry in a second language involves various difficulties, they acknowledge the values of utilizing poetry writing in second language classrooms. The results also show that writing poetry in a second language contains both positive and negative emotions, but positive ones are more frequently addressed. Most importantly, the data suggests that writing poetry in a second language is considered as an applicable practice in ESL/EFL language classrooms.

The Influence of the Tool Surface Texture on Friction and the Surface Layers Properties of Formed Component

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Jana Šugárová

2018-03-01

Full Text Available The morphological texturing of forming tool surfaces has high potential to reduce friction and tool wear and also has impact on the surface layers properties of formed material. In order to understand the effect of different types of tool textures, produced by nanosecond fibre laser, on the tribological conditions at the interface tool-formed material and on the integrity of formed part surface layers, the series of experimental investigations have been carried out. The coefficient of friction for different texture parameters (individual feature shape, including the depth profile of the cavities and orientation of the features relative to the material flow was evaluated via a Ring Test and the surface layers integrity of formed material (surface roughness and subsurface micro hardness was also experimentally analysed. The results showed a positive effect of surface texturing on the friction coefficients and the strain hardening of test samples material. Application of surface texture consisting of dimple-like depressions arranged in radial layout contributed to the most significant friction reduction of about 40%. On the other hand, this surface texture contributed to the increase of surface roughness parameters, Ra parameter increased from 0.49 μm to 2.19 μm and the Rz parameter increased from 0.99 μm to 16.79 μm.

Surface layer temperature inversion in the Bay of Bengal: Main characteristics and related mechanisms

Digital Repository Service at National Institute of Oceanography (India)

Pankajakshan, T.; Suresh, I.; Gautham, S.; PrasannaKumar, S.; Lengaigne, M.; Rao, R.R.; Neetu, S.; Hegde, A.

Surface layer temperature inversion (SLTI), a warm layer sandwiched between surface and subsurface colder waters, has been reported to frequently occur in conjunction with barrier layers in the Bay of Bengal (BoB), with potentially commensurable...

Thinking in English: A New Perspective on Teaching ESL

Science.gov (United States)

Muciaccia, John B.

2011-01-01

"Thinking in English" represents Dr. Muciaccia's unique method of teaching English to non-native English speakers. Unlike any other English as a Second Language (ESL) book, Muciaccia's book features the "cultural immersion" approach that he has developed and practiced to a fine degree. In addition to his methodology, Muciaccia includes words of…

Quantized layer growth at liquid-crystal surfaces

DEFF Research Database (Denmark)

Ocko, B. M.; Braslau, A.; Pershan, P. S.

1986-01-01

of the specular reflectivity is consistent with a sinusoidal density modulation, starting at the surface and terminating abruptly, after an integral number of bilayers. As the transition is approached the number of layers increases in quantized steps from zero to five before the bulk undergoes a first...

Two-Layer Variable Infiltration Capacity Land Surface Representation for General Circulation Models

Science.gov (United States)

Xu, L.

1994-01-01

A simple two-layer variable infiltration capacity (VIC-2L) land surface model suitable for incorporation in general circulation models (GCMs) is described. The model consists of a two-layer characterization of the soil within a GCM grid cell, and uses an aerodynamic representation of latent and sensible heat fluxes at the land surface. The effects of GCM spatial subgrid variability of soil moisture and a hydrologically realistic runoff mechanism are represented in the soil layers. The model was tested using long-term hydrologic and climatalogical data for Kings Creek, Kansas to estimate and validate the hydrological parameters. Surface flux data from three First International Satellite Land Surface Climatology Project Field Experiments (FIFE) intensive field compaigns in the summer and fall of 1987 in central Kansas, and from the Anglo-Brazilian Amazonian Climate Observation Study (ABRACOS) in Brazil were used to validate the mode-simulated surface energy fluxes and surface temperature.

Haematopoietic ESL-1 enables stem cell proliferation in the bone marrow by limiting TGFβ availability.

Science.gov (United States)

Leiva, Magdalena; Quintana, Juan A; Ligos, José M; Hidalgo, Andrés

2016-01-08

The life-long maintenance of haematopoietic stem and progenitor cells (HSPCs) critically relies on environmental signals produced by cells that constitute the haematopoietic niche. Here we report a cell-intrinsic mechanism whereby haematopoietic cells limit proliferation within the bone marrow, and show that this pathway is repressed by E-selectin ligand 1 (ESL-1). Mice deficient in ESL-1 display aberrant HSPC quiescence, expansion of the immature pool and reduction in niche size. Remarkably, the traits were transplantable and dominant when mutant and wild-type precursors coexisted in the same environment, but were independent of E-selectin, the vascular receptor for ESL-1. Instead, quiescence is generated by unrestrained production of the cytokine TGFβ by mutant HSPC, and in vivo or in vitro blockade of the cytokine completely restores the homeostatic properties of the haematopoietic niche. These findings reveal that haematopoietic cells, including the more primitive compartment, can actively shape their own environment.

Turbulent transport in the atmospheric surface layer

Energy Technology Data Exchange (ETDEWEB)

Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Science, Lund Univ., Lund (Sweden)

2012-04-15

In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to {approx}3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect

Turbulent transport in the atmospheric surface layer

International Nuclear Information System (INIS)

Tagesson, Torbern

2012-04-01

In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to ∼3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect of

Surface layers in the 4A group metals with implanted silicon ions

International Nuclear Information System (INIS)

Kovneristyj, Yu.K.; Vavilova, V.V.; Krasnopevtsev, V.V.; Galkin, L.N.; Kudyshev, A.N.; Klechkovskaya, V.V.

1987-01-01

A study was made on the change of structure and phase composition of fine near the surface layers of 4A group metals (Hf, Zr, Ti) during ion Si implantation and successive thermal annealing at elevated temperatures. Implantation of Si + ions with 30 or 16 keV energy in Ti, Zr and Hf at room temperature results to amorphization of metal surface layer. The surface hafnium and titanium layer with implanted Si atoms due to interaction with residual atmosphere of oxygen turns during annealing at 870 K to amorphous solid solution of HfO 2m or TiO 2 with Si, preventing further metal oxidation; layers of amorphous alloy are characterized by thermal stability up to 1270 K. Oxidation of the surface amorphous layer in residual oxygen atmosphere and its crystallization in ZrO 2 take place in result of Zr annealing with implanted Si ions at temperature not exceeding 870 K. Similar phenomena are observed in the case of hafnium with implanted oxygen ions or small dose of silicon ions. Thermal stability of amorphous layers produced during ion implantation of Si in Ti, Zr and Hf corresponds to scale resistance of monolithic alloys in Ti-Si, Zr-Si and Hf-Si systems

Tribological Characteristic of Titanium Alloy Surface Layers Produced by Diode Laser Gas Nitriding

Directory of Open Access Journals (Sweden)

Lisiecki A.

2016-06-01

Full Text Available In order to improve the tribological properties of titanium alloy Ti6Al4V composite surface layers Ti/TiN were produced during laser surface gas nitriding by means of a novel high power direct diode laser with unique characteristics of the laser beam and a rectangular beam spot. Microstructure, surface topography and microhardness distribution across the surface layers were analyzed. Ball-on-disk tests were performed to evaluate and compare the wear and friction characteristics of surface layers nitrided at different process parameters, base metal of titanium alloy Ti6Al4V and also the commercially pure titanium. Results showed that under dry sliding condition the commercially pure titanium samples have the highest coefficient of friction about 0.45, compared to 0.36 of titanium alloy Ti6Al4V and 0.1-0.13 in a case of the laser gas nitrided surface layers. The volume loss of Ti6Al4V samples under such conditions is twice lower than in a case of pure titanium. On the other hand the composite surface layer characterized by the highest wear resistance showed almost 21 times lower volume loss during the ball-on-disk test, compared to Ti6Al4V samples.

Preparation of Two-Layer Anion-Exchange Poly(ethersulfone Based Membrane: Effect of Surface Modification

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Lucie Zarybnicka

2016-01-01

Full Text Available The present work deals with the surface modification of a commercial microfiltration poly(ethersulfone membrane by graft polymerization technique. Poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride surface layer was covalently attached onto the poly(ethersulfone support layer to improve the membrane electrochemical properties. Followed by amination, a two-layer anion-exchange membrane was prepared. The effect of surface layer treatment using the extraction in various solvents on membrane morphological and electrochemical characteristics was studied. The membranes were tested from the point of view of water content, ion-exchange capacity, specific resistance, permselectivity, FT-IR spectroscopy, and SEM analysis. It was found that the two-layer anion-exchange membranes after the extraction using tetrahydrofuran or toluene exhibited smooth and porous surface layer, which resulted in improved ion-exchange capacity, electrical resistance, and permselectivity of the membranes.

Thermographic analysis of plasma facing components covered by carbon surface layer in tokamaks

International Nuclear Information System (INIS)

Gardarein, Jean-Laurent

2007-01-01

Tokamaks are reactors based on the thermonuclear fusion energy with magnetic confinement of the plasma. In theses machines, several MW are coupled to the plasma for about 10 s. A large part of this power is directed towards plasma facing components (PFC). For better understanding and control the heat flux transfer from the plasma to the surrounding wall, it is very important to measure the surface temperature of the PFC and to estimate the imposed heat flux. In most of tokamaks using carbon PFC, the eroded carbon is circulating in the plasma and redeposited elsewhere. During the plasma operations, this leads at some locations to the formation of thin or thick carbon layers usually poorly attached to the PFC. These surface layers with unknown thermal properties complicate the calculation of the heat flux from IR surface temperature measurements. To solve this problem, we develop first, inverse method to estimate the heat flux using thermocouple (not sensitive to the carbon surface layers) temperature measurements. Then, we propose a front face pulsed photothermal method allowing an estimation of layers thermal diffusivity, conductivity, effusivity and the thermal contact resistance between the layer and the tile. The principle is to study with an infrared sensor, the cooling of the layer surface after heating by a short laser pulse, this cooling depending on the thermal properties of the successive layers. (author) [fr

Surface influence upon vertical profiles in the nocturnal boundary layer

Science.gov (United States)

Garratt, J. R.

1983-05-01

Near-surface wind profiles in the nocturnal boundary layer, depth h, above relatively flat, tree-covered terrain are described in the context of the analysis of Garratt (1980) for the unstable atmospheric boundary layer. The observations at two sites imply a surface-based transition layer, of depth z *, within which the observed non-dimensional profiles Φ M 0 are a modified form of the inertial sub-layer relation Φ _M ( {{z L}} = ( {{{1 + 5_Z } L}} ) according to Φ _M^{{0}} ˜eq ( {{{1 + 5z} L}} )exp [ { - 0.7( {{{1 - z} z}_ * } )] , where z is height above the zero-plane displacement and L is the Monin-Obukhov length. At both sites the depth z * is significantly smaller than the appropriate neutral value ( z * N ) found from the previous analysis, as might be expected in the presence of a buoyant sink for turbulent kinetic energy.

The microstructure of the surface layer of magnesium laser alloyed with aluminum and silicon

International Nuclear Information System (INIS)

Dziadoń, Andrzej; Mola, Renata; Błaż, Ludwik

2016-01-01

The surface layer under analysis was formed as a result of diffusion bonding of a thin AlSi20 plate to a magnesium substrate followed by laser melting. Depending on the process parameters, the laser beam melted the AlSi20 plate only or the AlSi20 plate and a layer of the magnesium surface adjacent to it. Two types of microstructure of the remelted layer were thus analyzed. If the melting zone was limited to the AlSi20 plate, the microstructure of the surface layer was typical of a rapidly solidified hypereutectic Al–Si alloy. Since, however, the liquid AlSi20 reacted with the magnesium substrate, the following intermetallic phases formed: Al 3 Mg 2 , Mg 17 Al 12 and Mg 2 Si. The microstructure of the modified surface layer of magnesium was examined using optical, scanning electron and transmission electron microscopy. The analysis of the surface properties of the laser modified magnesium revealed that the thin layer has a microstructure of a rapidly solidified Al–Si alloy offering good protection against corrosion. By contrast, the surface layer containing particles of intermetallic phases was more resistant to abrasion but had lower corrosion resistance than the silumin type layer. - Highlights: •A CO 2 laser was used for surface alloying of Mg with AlSi20. •Before alloying, an AlSi20 plate was diffusion bonded with the Mg substrate. •The process parameters affected the alloyed layer microstructure and properties. •With melting limited to AlSi20, the layer had a structure of rapidly solidified AlSi20. •Mg–Al and Mg–Si phases were present when both the substrate and the plate were melted.

The microstructure of the surface layer of magnesium laser alloyed with aluminum and silicon

Energy Technology Data Exchange (ETDEWEB)

Dziadoń, Andrzej [Faculty of Mechatronics and Mechanical Engineering, Kielce University of Technology, Al. Tysiąclecia P.P. 7, 25-314 Kielce (Poland); Mola, Renata, E-mail: rmola@tu.kielce.pl [Faculty of Mechatronics and Mechanical Engineering, Kielce University of Technology, Al. Tysiąclecia P.P. 7, 25-314 Kielce (Poland); Błaż, Ludwik [Department of Structure and Mechanics of Solids, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków (Poland)

2016-08-15

The surface layer under analysis was formed as a result of diffusion bonding of a thin AlSi20 plate to a magnesium substrate followed by laser melting. Depending on the process parameters, the laser beam melted the AlSi20 plate only or the AlSi20 plate and a layer of the magnesium surface adjacent to it. Two types of microstructure of the remelted layer were thus analyzed. If the melting zone was limited to the AlSi20 plate, the microstructure of the surface layer was typical of a rapidly solidified hypereutectic Al–Si alloy. Since, however, the liquid AlSi20 reacted with the magnesium substrate, the following intermetallic phases formed: Al{sub 3}Mg{sub 2}, Mg{sub 17}Al{sub 12} and Mg{sub 2}Si. The microstructure of the modified surface layer of magnesium was examined using optical, scanning electron and transmission electron microscopy. The analysis of the surface properties of the laser modified magnesium revealed that the thin layer has a microstructure of a rapidly solidified Al–Si alloy offering good protection against corrosion. By contrast, the surface layer containing particles of intermetallic phases was more resistant to abrasion but had lower corrosion resistance than the silumin type layer. - Highlights: •A CO{sub 2} laser was used for surface alloying of Mg with AlSi20. •Before alloying, an AlSi20 plate was diffusion bonded with the Mg substrate. •The process parameters affected the alloyed layer microstructure and properties. •With melting limited to AlSi20, the layer had a structure of rapidly solidified AlSi20. •Mg–Al and Mg–Si phases were present when both the substrate and the plate were melted.

Oral Communication in ESL through Improvisations, Playwriting and Rehearsals

Science.gov (United States)

Gill, Chamkaur

2013-01-01

The application of drama strategies which focus more on meaning than on form can provide an impetus for ESL learners to be more confident about speaking, thereby increasing the quantity of their spoken English. This paper discusses existing research and the author's own experiences in an attempt to highlight the positive effects of improvisations,…

What Makes Critical Thinking Critical for Adult ESL Students

Science.gov (United States)

Miekley, Joshua P.

2014-01-01

Critical-thinking skills help to prepare adult education students for a successful transition to college degree programs and for job advancement. Yet fostering critical thinking poses a challenge to ESL instructors. Brookfield (2012) provides a way forward for adult educators when he explains that the crux of critical thinking is to discover one's…

Anxiety and Academic Reading Performance among Malay ESL Learners

Science.gov (United States)

Mohd. Zin, Zuhana; Rafik-Galea, Shameem

2010-01-01

Research into the factors that contribute to reading performance decrement in L2 reading among ESL university students is still being extensively researched in the context of ELT. This is because successful academic performance is highly dependent on good reading ability. While it is widely accepted that poor reading performance is due to lack of…

Maximising Asian ESL Learners’ Communicative Oral English via Drama

Directory of Open Access Journals (Sweden)

Chamkaur Gill

2016-10-01

Full Text Available This paper proposes that activities based on a variety of drama-based techniques could be valuable in giving Asian ESL learners opportunities to use communicative spoken English confidently and without restraint during their time in English-language-speaking countries. These learners often get anxious when in situations where they are required to speak in English. Fears about making errors related to grammar, fluency and clarity that might cause them to be embarrassed stand in the way of unencumbered speech output. In addition, cultural issues linked to voice-projection and body language can hinder oral interaction in English and hamper their motivation to speak. They are, therefore, deprived of much-needed speaking practice. I find that drama lets my students speak communicatively, free of the dread of constant correction, in a relaxed and enjoyable learner-centred environment that appears to help diminish their anxiety and inhibitions. As a result, their motivation to speak increases, leading to extended speech production. Keywords: ESL, Asian students’ traits, communicative oral English, drama variations

A numerical model for chemical reaction on slag layer surface and slag layer behavior in entrained-flow gasifier

Directory of Open Access Journals (Sweden)

Liu Sheng

2013-01-01

Full Text Available The paper concerns with slag layer accumulation, chemical reaction on slag layer surface, and slag layer flow, heat and mass transfer on the wall of entrained-flow coal gasifier. A slag layer model is developed to simulate slag layer behaviors in the coal gasifier. This 3-D model can predict temperature, slag particle disposition rate, disposition particle composition, and syngas distribution in the gasifier hearth. The model is used to evaluate the effects of O2/coal ratio on slag layer behaviors.

Literature and Language Teaching: Exploring Literary Texts with the Language Learner and Re-Creating Literature in the ESL Classroom.

Science.gov (United States)

Lazar, Gillian; Heath, Shirley Brice

1996-01-01

Two educators discuss the role literature plays in the English as a Second Language (ESL) classroom. One emphasizes that literary texts are a source for classroom activities that can motivate learners. The other points out that the English writings of ESL students about their travels and friends published in newsletters and journals generate…

The Emergent Nature of Strategic Mediation in ESL Teacher Education

Science.gov (United States)

Kaur, Kuldip

2015-01-01

This article concentrates on a practitioner-driven approach to teacher education aimed at advancing ESL teachers' instructional knowledge about writing. Based on activity-centred interaction between a group of Malaysian English teachers and their teacher educator, the discussion demonstrates (1) the emergent, unplanned nature of strategic…

The Attitudes of Students From ESL And EFL Countries To English

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Muhammad Hasbi

2013-06-01

Full Text Available This research is to study the attitudes of English students from English as a Second Language (ESL and English as a Foreign Language (EFL country in English and Foreign Languages University (EFL University, Hyderabad to English. This is a descriptive-quantitative research with a survey method. The attitudes researched include those to listening, speaking, reading, and writing. The data was taken through questionnaire consisting of 20 questions. The findings of this study showed that the English students in EFL University have neutral-to-positive attitudes to Listening, positive attitudes to Speaking, positive attitudes to Reading, and poor attitudes to Writing. In addition, the English students from ESL country have better attitudes to Reading (positive and Writing (neutral and those from EFL country have better attitudes to Speaking (neutral-to-positive and Listening (neutral-to-positive.

The Attitudes of Students from ESL and EFL Countries to English

Directory of Open Access Journals (Sweden)

Muhamad Hasbi

2013-06-01

Full Text Available This research is to study the attitudes of English students from English as a Second Language (ESL and English as a Foreign Language (EFL country in English and Foreign Languages University (EFL University, Hyderabad to English. This is a descriptive-quantitative research with a survey method. The attitudes researched include those to listening, speaking, reading, and writing. The data was taken through questionnaire consisting of 20 questions. The findings of this study showed that the English students in EFL University have neutral-to-positive attitudes to Listening, positive attitudes to Speaking, positive attitudes to Reading, and poor attitudes to Writing. In addition, the English students from ESL country have better attitudes to Reading (positive and Writing (neutral and those from EFL country have better attitudes to Speaking (neutral-to-positive and Listening (neutral-to-positive.

Detection of Entrainment Influences on Surface-Layer Measurements and Extension of Monin–Obukhov Similarity Theory

NARCIS (Netherlands)

Boer, van de A.; Moene, A.F.; Graf, A.; Schüttemeyer, D.; Simmer, C.

2014-01-01

We present a method to detect influences of boundary-layer processes on surface-layer measurements, using statistics and spectra of surface-layer variables only. We validated our detection method with boundary-layer measurements. Furthermore, we confirm that Monin–Obukhov similarity functions fit

Surface Morphology Transformation Under High-Temperature Annealing of Ge Layers Deposited on Si(100).

Science.gov (United States)

Shklyaev, A A; Latyshev, A V

2016-12-01

We study the surface morphology and chemical composition of SiGe layers after their formation under high-temperature annealing at 800-1100 °C of 30-150 nm Ge layers deposited on Si(100) at 400-500 °C. It is found that the annealing leads to the appearance of the SiGe layers of two types, i.e., porous and continuous. The continuous layers have a smoothened surface morphology and a high concentration of threading dislocations. The porous and continuous layers can coexist. Their formation conditions and the ratio between their areas on the surface depend on the thickness of deposited Ge layers, as well as on the temperature and the annealing time. The data obtained suggest that the porous SiGe layers are formed due to melting of the strained Ge layers and their solidification in the conditions of SiGe dewetting on Si. The porous and dislocation-rich SiGe layers may have properties interesting for applications.

Layer-by-layer modification of high surface curvature nanoparticles with weak polyelectrolytes using a multiphase solvent precipitation process.

Science.gov (United States)

Nagaraja, Ashvin T; You, Yil-Hwan; Choi, Jeong-Wan; Hwang, Jin-Ha; Meissner, Kenith E; McShane, Michael J

2016-03-15

The layer-by-layer modification of ≈5 nm mercaptocarboxylic acid stabilized gold nanoparticles was studied in an effort to illustrate effective means to overcome practical issues in handling and performing surface modification of such extremely small materials. To accomplish this, each layer deposition cycle was separated into a multi-step process wherein solution pH was controlled in two distinct phases of polyelectrolyte adsorption and centrifugation. Additionally, a solvent precipitation step was introduced to make processing more amenable by concentrating the sample and exchanging solution pH before ultracentrifugation. The pH-dependent assembly on gold nanoparticles was assessed after each layer deposition cycle by monitoring the plasmon peak absorbance location, surface charge, and the percentage of nanoparticles recovered. The selection of solution pH during the adsorption phase was found to be a critical parameter to enhance particle recovery and maximize surface charge when coating with weak polyelectrolytes. One bilayer was deposited with a high yield and the modified particles exhibited enhanced colloidal stability across a broad pH range and increased ionic strength. These findings support the adoption of this multi-step processing approach as an effective and generalizable approach to improve stability of high surface curvature particles. Copyright © 2015 Elsevier Inc. All rights reserved.

Measurement of grassland evaporation using a surface-layer ...

African Journals Online (AJOL)

Measurement of grassland evaporation using a surface-layer scintillometer. ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search ... of soil heat flux and net irradiance, evaporation rates were calculated as a residual of the ...

Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

Science.gov (United States)

Brown, Matthew A.; Abbas, Zareen; Kleibert, Armin; Green, Richard G.; Goel, Alok; May, Sylvio; Squires, Todd M.

2016-01-01

The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li+ , Na+ , K+ , and Cs+ ) in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

Diffusion of C and Cr During Creation of Surface Layer on Cast Steel Casting

Directory of Open Access Journals (Sweden)

Szajnar J.

2014-10-01

Full Text Available In paper a method of improvement in utility properties of unalloyed cast steel casting in result of diffusion of C and Cr in process of creation of surface layer is presented. The aim of paper was determination of diffusion range of basic elements of alloyed surface layer. Moreover a quantitative analysis of carbides phase strengthens alloyed surface layer of casting was carried out. The results of studies shown that important factors of surface layer creation are maximal temperature Tmax on granular insert – cast steel boundary dependent of pouring temperature, granularity Zw of Fe-Cr-C alloy insert and thickness of casting wall gśo. On the basis of obtained results was affirmed that with increase of thickness of casting wall increases range of diffusion in solid state in Fe-Cr-C grains and in liquid state. Moreover the range of Tmax = 13001500oC favours creation of the proper alloyed surface layers on cast steel.

Hierarchical Composite Membranes with Robust Omniphobic Surface Using Layer-By-Layer Assembly Technique

KAUST Repository

Woo, Yun Chul

2018-01-17

In this study, composite membranes were fabricated via layer-by-layer (LBL) assembly of negatively-charged silica aerogel (SiA) and 1H, 1H, 2H, 2H – Perfluorodecyltriethoxysilane (FTCS) on a polyvinylidene fluoride phase inversion membrane, and interconnecting them with positively-charged poly(diallyldimethylammonium chloride) (PDDA) via electrostatic interaction. The results showed that the PDDA-SiA-FTCS coated membrane had significantly enhanced the membrane structure and properties. New trifluoromethyl and tetrafluoroethylene bonds appeared at the surface of the coated membrane, which led to lower surface free energy of the composite membrane. Additionally, the LBL membrane showed increased surface roughness. The improved structure and property gave the LBL membrane an omniphobic property, as indicated by its good wetting resistance. The membrane performed a stable air gap membrane distillation (AGMD) flux of 11.22 L/m2h with very high salt rejection using reverse osmosis brine from coal seam gas produced water as feed with the addition of up to 0.5 mM SDS solution. This performance was much better compared to those of the neat membrane. The present study suggests that the enhanced membrane properties with good omniphobicity via LBL assembly make the porous membranes suitable for long-term AGMD operation with stable permeation flux when treating challenging saline wastewater containing low surface tension organic contaminants.

Resistivity scaling due to electron surface scattering in thin metal layers

Science.gov (United States)

Zhou, Tianji; Gall, Daniel

2018-04-01

The effect of electron surface scattering on the thickness-dependent electrical resistivity ρ of thin metal layers is investigated using nonequilibrium Green's function density functional transport simulations. Cu(001) thin films with thickness d =1 -2 nm are used as a model system, employing a random one-monolayer-high surface roughness and frozen phonons to cause surface and bulk scattering, respectively. The zero-temperature resistivity increases from 9.7 ±1.0 μ Ω cm at d =1.99 nm to 18.7 ±2.6 μ Ω cm at d =0.9 0 nm, contradicting the asymptotic T =0 prediction from the classical Fuchs-Sondheimer model. At T =9 00 K, ρ =5.8 ±0.1 μ Ω cm for bulk Cu and ρ =13.4 ±1.1 and 22.5 ±2.4 μ Ω cm for layers with d =1.99 and 0.90 nm, respectively, indicating an approximately additive phonon contribution which, however, is smaller than for bulk Cu or atomically smooth layers. The overall data indicate that the resistivity contribution from surface scattering is temperature-independent and proportional to 1 /d , suggesting that it can be described using a surface-scattering mean-free path λs for 2D transport which is channel-independent and proportional to d . Data fitting indicates λs=4 ×d for the particular simulated Cu(001) surfaces with a one-monolayer-high surface roughness. The 1 /d dependence deviates considerably from previous 1 /d2 predictions from quantum models, indicating that the small-roughness approximation in these models is not applicable to very thin (<2 nm) layers, where the surface roughness is a considerable fraction of d .

A manufacturing method for multi-layer polysilicon surface-micromachining technology

Energy Technology Data Exchange (ETDEWEB)

Sniegowski, J.J.; Rodgers, M.S.

1998-01-01

An advanced manufacturing technology which provides multi-layered polysilicon surface micromachining technology for advanced weapon systems is presented. Specifically, the addition of another design layer to a 4 levels process to create a 5 levels process allows consideration of fundamentally new architecture in designs for weapon advanced surety components.

The Impact of Interface on ESL Reading Comprehension and Strategy Use: A Comparison of E-Books and Paper Texts

Science.gov (United States)

Isaacson, Sarah A.

2017-01-01

The use of e-books in postsecondary education is projected to increase, yet many English as a second language (ESL) institutions have not yet incorporated e-books into their curricula, in part due to a dearth of research regarding their potential impacts on ESL reading comprehension and strategy use. This study fills a gap in the existing research…

Optimized Estimation of Surface Layer Characteristics from Profiling Measurements

Directory of Open Access Journals (Sweden)

Doreene Kang

2016-01-01

Full Text Available New sampling techniques such as tethered-balloon-based measurements or small unmanned aerial vehicles are capable of providing multiple profiles of the Marine Atmospheric Surface Layer (MASL in a short time period. It is desirable to obtain surface fluxes from these measurements, especially when direct flux measurements are difficult to obtain. The profiling data is different from the traditional mean profiles obtained at two or more fixed levels in the surface layer from which surface fluxes of momentum, sensible heat, and latent heat are derived based on Monin-Obukhov Similarity Theory (MOST. This research develops an improved method to derive surface fluxes and the corresponding MASL mean profiles of wind, temperature, and humidity with a least-squares optimization method using the profiling measurements. This approach allows the use of all available independent data. We use a weighted cost function based on the framework of MOST with the cost being optimized using a quasi-Newton method. This approach was applied to seven sets of data collected from the Monterey Bay. The derived fluxes and mean profiles show reasonable results. An empirical bias analysis is conducted using 1000 synthetic datasets to evaluate the robustness of the method.

SURFACE LAYER ACCRETION IN CONVENTIONAL AND TRANSITIONAL DISKS DRIVEN BY FAR-ULTRAVIOLET IONIZATION

International Nuclear Information System (INIS)

Perez-Becker, Daniel; Chiang, Eugene

2011-01-01

Whether protoplanetary disks accrete at observationally significant rates by the magnetorotational instability (MRI) depends on how well ionized they are. Disk surface layers ionized by stellar X-rays are susceptible to charge neutralization by small condensates, ranging from ∼0.01 μm sized grains to angstrom-sized polycyclic aromatic hydrocarbons (PAHs). Ion densities in X-ray-irradiated surfaces are so low that ambipolar diffusion weakens the MRI. Here we show that ionization by stellar far-ultraviolet (FUV) radiation enables full-blown MRI turbulence in disk surface layers. Far-UV ionization of atomic carbon and sulfur produces a plasma so dense that it is immune to ion recombination on grains and PAHs. The FUV-ionized layer, of thickness 0.01-0.1 g cm -2 , behaves in the ideal magnetohydrodynamic limit and can accrete at observationally significant rates at radii ∼> 1-10 AU. Surface layer accretion driven by FUV ionization can reproduce the trend of increasing accretion rate with increasing hole size seen in transitional disks. At radii ∼<1-10 AU, FUV-ionized surface layers cannot sustain the accretion rates generated at larger distance, and unless turbulent mixing of plasma can thicken the MRI-active layer, an additional means of transport is needed. In the case of transitional disks, it could be provided by planets.

Recycling inflow method for simulations of spatially evolving turbulent boundary layers over rough surfaces

Science.gov (United States)

Yang, Xiang I. A.; Meneveau, Charles

2016-01-01

The technique by Lund et al. to generate turbulent inflow for simulations of developing boundary layers over smooth flat plates is extended to the case of surfaces with roughness elements. In the Lund et al. method, turbulent velocities on a sampling plane are rescaled and recycled back to the inlet as inflow boundary condition. To rescale mean and fluctuating velocities, appropriate length scales need be identified and for smooth surfaces, the viscous scale lν = ν/uτ (where ν is the kinematic viscosity and uτ is the friction velocity) is employed for the inner layer. Different from smooth surfaces, in rough wall boundary layers the length scale of the inner layer, i.e. the roughness sub-layer scale ld, must be determined by the geometric details of the surface roughness elements and the flow around them. In the proposed approach, it is determined by diagnosing dispersive stresses that quantify the spatial inhomogeneity caused by the roughness elements in the flow. The scale ld is used for rescaling in the inner layer, and the boundary layer thickness δ is used in the outer region. Both parts are then combined for recycling using a blending function. Unlike the blending function proposed by Lund et al. which transitions from the inner layer to the outer layer at approximately 0.2δ, here the location of blending is shifted upwards to enable simulations of very rough surfaces in which the roughness length may exceed the height of 0.2δ assumed in the traditional method. The extended rescaling-recycling method is tested in large eddy simulation of flow over surfaces with various types of roughness element shapes.

Text-Selection for Teaching Reading to ESL Tertiary Students: A Study on Genre and Content Preferences

Directory of Open Access Journals (Sweden)

Razanawati Nordin

2017-01-01

Full Text Available Most learners studying English language feel that their educators use irrelevant, uninteresting, and culturally unfamiliar reading materials for teaching reading. As a result, most of them struggle to comprehend the English language texts used by the teachers. Therefore, the aim of this research is to investigate the genre and content preferences of ESL tertiary learners in UiTM Kedah, Malaysia. A two-part questionnaire was administered to 132 respondents aged 20 to 23 years old who are presently furthering their undergraduate studies in Accountancy, Administrative Science and Policy Studies, Business Management, Industrial Design, and Information Management. The results of the study show that these ESL tertiary learners prefer texts from the websites and blogs; and their preferred reading contents are dealing with Business Management, watching movies and listening to music. This article offers guidance to ESL teachers to select L2 reading texts based on the students’ preferred genre and content.

Observing the interactive qualities of L2 instructional practices in ESL and FSL classrooms

Directory of Open Access Journals (Sweden)

Michael Zuniga

2016-03-01

Full Text Available Discourse features that promote the generation of interactionally modified input and output, such as negotiation for meaning, have been shown to significantly enhance second language acquisition. Research has also identified several characteristics of instructional practices that render them more or less propitious to the generation of these discourse features. While various classroom observation studies have successfully measured the communicative orientation of classroom environments, most of the indicators of interactivity analyzed in those studies were obtained through micro-level discourse analyses and not through macro-level analyses of task-related factors shown to directly influence the interactivity of instructional practices. Such a macro-level scale has potential practical implications for teachers and administrators seeking an efficient tool for assessing and improving the interactivity afforded by a given curriculum. The objective of the present study was therefore to develop macro-level scale to determine the extent to which teachers of French and English as a second language use interaction-friendly instructional practices. Using an observation scheme designed to code data on factors shown to influence interactivity, 63 hours of FSL and ESL classes from secondary schools in the Montreal area were observed and analyzed. Results indicate clear differences between the two groups. While both ESL and FSL classes were less teacher-centered than those observed in previous studies, they were still rated as not-very-interactive. Target language differences showed that the FSL classes were more teacher-centered and characterized by fewer interaction-friendly tasks and activities than the ESL classes. Task characteristics, reasons for ESL and FSL differences and recommendations for improvement are discussed.

Effects of Surface Roughness and Mechanical Properties of Cover-Layer on Near-Field Optical Recording

Science.gov (United States)

Kim, Jin-Hong; Lee, Jun-Seok; Lim, Jungshik; Seo, Jung-Kyo

2009-03-01

Narrow gap distance in cover-layer incident near-field recording (NFR) configuration causes a collision problem in the interface between a solid immersion lens and a disk surface. A polymer cover-layer with smooth surface results in a stable gap servo while a nanocomposite cover-layer with high refractive index shows a collision problem during the gap servo test. Even though a dielectric cover-layer, in which the surface is rougher than the polymer, supplements the mechanical properties, an unclear eye pattern due to an unstable gap servo can be obtained after a chemical mechanical polishing. Not only smooth surface but also good mechanical properties of cover-layer are required for the stable gap servo in the NFR.

The dynamic deformation of a layered viscoelastic medium under surface excitation

International Nuclear Information System (INIS)

Aglyamov, Salavat R; Karpiouk, Andrei B; Emelianov, Stanislav Y; Wang, Shang; Li, Jiasong; Larin, Kirill V; Twa, Michael

2015-01-01

In this study the dynamic behavior of a layered viscoelastic medium in response to the harmonic and impulsive acoustic radiation force applied to its surface was investigated both theoretically and experimentally. An analytical solution for a layered viscoelastic compressible medium in frequency and time domains was obtained using the Hankel transform. A special incompressible case was considered to model soft biological tissues. To verify our theoretical model, experiments were performed using tissue-like gel-based phantoms with varying mechanical properties. A 3.5 MHz single-element focused ultrasound transducer was used to apply the radiation force at the surface of the phantoms. A phase-sensitive optical coherence tomography system was used to track the displacements of the phantom surface. Theoretically predicted displacements were compared with experimental measurements. The role of the depth dependence of the elastic properties of a medium in its response to an acoustic pulse at the surface was studied. It was shown that the low-frequency vibrations at the surface are more sensitive to the deep layers than high-frequency ones. Therefore, the proposed model in combination with spectral analysis can be used to evaluate depth-dependent distribution of the mechanical properties based on the measurements of the surface deformation. (paper)

Surface reactivity and layer analysis of chemisorbed reaction films in ...

Indian Academy of Sciences (India)

Administrator

Surface reactivity and layer analysis of chemisorbed reaction films in ... in the nitrogen environment. Keywords. Surface reactivity ... sium (Na–K) compounds in the coating or core of the ..... Barkshire I R, Pruton M and Smith G C 1995 Appl. Sur.

Electron spectroscopy of the interface carbon layer formation on the cleavage surfaces of the layered semiconductor In4Se3 crystals

International Nuclear Information System (INIS)

Galiy, P.V.; Musyanovych, A.V.; Nenchuk, T.M.

2005-01-01

The results of the quantitative X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) of the interface carbon layer formation on the cleavage surfaces of the layered semiconductor In 4 Se 3 crystals are presented. The carbon coating formation occurs as the result of interaction of the air and residual gases atmosphere in ultra high vacuum (UHV) Auger spectrometer chamber with atomic clean interlayer cleavage surfaces of the crystals. The kinetics and peculiarities of interfacial carbon layer formation on the cleavage surfaces of the crystals, elemental and phase composition of the interface have been studied by quantitative XPS, AES and mass-spectroscopy

The Construction of Collective Identity in Malaysian ESL Secondary Classrooms

Science.gov (United States)

Idrus, Faizah; Nazri, Nas Idayu Mohd

2016-01-01

This study seeks to identify the construction of collective identity in ESL classroom among students in a secondary school in Selangor, Malaysia. Identity construction can be helpful in supporting students academically and socially, especially in the English language classrooms. Being non-native speakers, students may have the tendency to feel…

Pedagogical Content Knowledge: A Case Study of ESL Teacher Educator

Science.gov (United States)

Liu, Siping

2013-01-01

This single-case study focuses on the pedagogical content knowledge (PCK) of a university faculty member teaching Second Language Acquisition to elementary teacher candidates. The research questions address the pattern and development of PCK for ESL teaching. Based on data from classroom observation, interviews and document review, the study finds…

Teaching for Diversity: Addressing Diversity Issues in Responsive ESL Instruction

Science.gov (United States)

Fu, Jing

2013-01-01

Student diversity has become a typical phenomenon in American public schools. The impact of increasing diversity on literacy instruction is unchallenged. Teachers reinforce this message by often citing ESL student diversity as a barrier for literacy teaching. In order to better understand the complexity of diversity issues, I explored two ESL…

Investigating ESL Students' Performance on Outcomes Assessments in Higher Education

Science.gov (United States)

Lakin, Joni M.; Elliott, Diane Cardenas; Liu, Ou Lydia

2012-01-01

Outcomes assessments are gaining great attention in higher education because of increased demand for accountability. These assessments are widely used by U.S. higher education institutions to measure students' college-level knowledge and skills, including students who speak English as a second language (ESL). For the past decade, the increasing…

Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

Directory of Open Access Journals (Sweden)

Matthew A. Brown

2016-01-01

Full Text Available The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li^{+}, Na^{+}, K^{+}, and Cs^{+} in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

NASA MSFC Electrostatic Levitator (ESL) Rapid Quench System

Science.gov (United States)

SanSoucie, Michael P.; Craven, Paul D.

2014-01-01

Electrostatic levitation, a form of containerless processing, is an important tool in materials research. Levitated specimens are free from contact with a container; therefore, heterogeneous nucleation on container walls is not possible. This allows studies of deeply undercooled melts. Furthermore, studies of high-temperature, highly reactive materials are also possible. Studies of the solidification and crystallization of undercooled melts is vital to the understanding of microstructure development, particularly the formation of alloys with unique properties by rapid solidification. The NASA Marshall Space Flight Center (MSFC) Electrostatic Levitator (ESL) lab has recently been upgraded to allow for rapid quenching of levitated materials. The ESL Rapid Quench System uses a small crucible-like vessel that can be partially filled with a low melting point material, such as a Gallium alloy, as a quench medium. An undercooled sample can be dropped into the vessel to rapidly quench the sample. A carousel with nine vessels sits below the bottom electrode assembly. This system allows up to nine rapid quenches before having to break vacuum and remove the vessels. This new Rapid Quench System will allow materials science studies of undercooled materials and new materials development. In this presentation, the system is described and initial results are presented.

Polyethylene imine/graphene oxide layer-by-layer surface functionalization for significantly improved limit of detection and binding kinetics of immunoassays on acrylate surfaces.

Science.gov (United States)

Miyazaki, Celina M; Mishra, Rohit; Kinahan, David J; Ferreira, Marystela; Ducrée, Jens

2017-10-01

Antibody immobilization on polymeric substrates is a key manufacturing step for microfluidic devices that implement sample-to-answer automation of immunoassays. In this work, a simple and versatile method to bio-functionalize poly(methylmethacrylate) (PMMA), a common material of such "Lab-on-a-Chip" systems, is proposed; using the Layer-by-Layer (LbL) technique, we assemble nanostructured thin films of poly(ethylene imine) (PEI) and graphene oxide (GO). The wettability of PMMA surfaces was significantly augmented by the surface treatment with (PEI/GO) 5 film, with an 81% reduction of the contact angle, while the surface roughness increased by 600%, thus clearly enhancing wettability and antibody binding capacity. When applied to enzyme-linked immunosorbent assays (ELISAs), the limit of detection of PMMA surface was notably improved from 340pgmL -1 on commercial grade polystyrene (PS) and 230pgmL -1 on plain PMMA surfaces to 130pgmL -1 on (PEI/GO) 5 treated PMMA. Furthermore, the accelerated antibody adsorption kinetics on the LbL films of GO allowed to substantially shorten incubation times, e.g. for anti-rat IgG adsorption from 2h down to 15min on conventional and treated surfaces, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface passivation of InP solar cells with InAlAs layers

Science.gov (United States)

Jain, Raj K.; Flood, Dennis J.; Landis, Geoffrey A.

1993-01-01

The efficiency of indium phosphide solar cells is limited by high values of surface recombination. The effect of a lattice-matched In(0.52)Al(0.48)As window layer material for InP solar cells, using the numerical code PC-1D is investigated. It was found that the use of InAlAs layer significantly enhances the p(+)n cell efficiency, while no appreciable improvement is seen for n(+)p cells. The conduction band energy discontinuity at the heterojunction helps in improving the surface recombination. An optimally designed InP cell efficiency improves from 15.4 percent to 23 percent AMO for a 10 nm thick InAlAs layer. The efficiency improvement reduces with increase in InAlAs layer thickness, due to light absorption in the window layer.

Whirlwinds and hairpins in the atmospheric surface layer

NARCIS (Netherlands)

Oncley, Steven P.; Hartogensis, O.K.; Tong, Chenning

2016-01-01

Vortices in the atmospheric surface layer are characterized using observations at unprecedented resolution from a fixed array of 31 turbulence sensors. During the day, these vortices likely are dust devils, though no visual observations are available for confirmation. At night, hairpin vortices

Time-resolved PIV measurements of the atmospheric boundary layer over wind-driven surface waves

Science.gov (United States)

Markfort, Corey; Stegmeir, Matt

2017-11-01

Complex interactions at the air-water interface result in two-way coupling between wind-driven surface waves and the atmospheric boundary layer (ABL). Turbulence generated at the surface plays an important role in aquatic ecology and biogeochemistry, exchange of gases such as oxygen and carbon dioxide, and it is important for the transfer of energy and controlling evaporation. Energy transferred from the ABL promotes the generation and maintenance of waves. A fraction of the energy is transferred to the surface mixed layer through the generation of turbulence. Energy is also transferred back to the ABL by waves. There is a need to quantify the details of the coupled boundary layers of the air-water system to better understand how turbulence plays a role in the interactions. We employ time-resolved PIV to measure the detailed structure of the air and water boundary layers under varying wind and wave conditions in the newly developed IIHR Boundary-Layer Wind-Wave Tunnel. The facility combines a 30-m long recirculating water channel with an open-return boundary layer wind tunnel. A thick turbulent boundary layer is developed in the 1 m high air channel, over the water surface, allowing for the study of boundary layer turbulence interacting with a wind-driven wave field.

Patterned hydrophobic and hydrophilic surfaces of ultra-smooth nanocrystalline diamond layers

Energy Technology Data Exchange (ETDEWEB)

Mertens, M., E-mail: michael.mertens@uni-ulm.de [Institute of Micro and Nanomaterials, Ulm University, 89081 Ulm (Germany); Mohr, M.; Brühne, K.; Fecht, H.J. [Institute of Micro and Nanomaterials, Ulm University, 89081 Ulm (Germany); Łojkowski, M.; Święszkowski, W. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Łojkowski, W. [Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw (Poland)

2016-12-30

Highlights: • Hydrophobic and hydrophilic properties on fluorine-, hydrogen- and oxygen- terminated ultra-nanocrystalline diamond films. • Micropatterned - multi-terminated layers with both hydrophobic and hydrophilic areas on one sample. • Visualization of multi-terminated surfaces by e.g. SEM and LFM. • Roughness and friction investigations on different terminated surfaces. • Smooth and biocompatible surfaces with same roughness regardless of hydrophobicity for microbiological investigations. - Abstract: In this work, we show that ultra nanocrystalline diamond (UNCD) surfaces have been modified to add them hydrophobic and hydrophilic properties. The nanocrystalline diamond films were deposited using the hot filament chemical vapor deposition (HFCVD) technique. This allows growing diamond on different substrates which can be even 3D or structured. Silicon and, for optical applications, transparent quartz glass are the preferred substrates for UNCD layers growth. Fluorine termination leads to strong hydrophobic properties as indicated by a high contact angle for water of more than 100°. Hydrogen termination shows lesser hydrophobic behavior. Hydrophilic characteristics has been realised with oxygen termination. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) measurements confirm the oxygen and fluorine- termination on the nanocrystalline diamond surface. Further, by micropatterning using photolithography, multi-terminated layers have been created with both hydrophobic and hydrophilic areas. In addition, we have shown that retermination is achieved, and the properties of the surface have been changed from hydrophobic to hydrophilic and vice versa. Micro- roughness and stress in the grown film influences slightly the wetting angle as well. The opportunity to realize local differences in hydrophobicity on nanocrystalline diamond layers, in any size or geometry, offers interesting applications for example in

Pre-reading activities in EFL/ESL reading textbooks and Turkish preparatory school teachers' attitudes toward pre-reading activities

OpenAIRE

Jecksembieyva, Nurgaisha

1993-01-01

Ankara : Faculty of Humanities and Letters and the Institute of Economics and Social Sciences of Bilkent University, 1993. Thesis (Master's) -- -Bilkent University, 1993. Includes bibliographical references leaves 35-40. The main focus of this study was to investigate pre-reading activities in EFL/ESL reading textbooks and to determine teachers' attitudes toward pre-reading activities. Fifteen reading textbooks for EFL/ESL students for different proficiency levels (beginning, interm...

Automated Error Detection for Developing Grammar Proficiency of ESL Learners

Science.gov (United States)

Feng, Hui-Hsien; Saricaoglu, Aysel; Chukharev-Hudilainen, Evgeny

2016-01-01

Thanks to natural language processing technologies, computer programs are actively being used not only for holistic scoring, but also for formative evaluation of writing. CyWrite is one such program that is under development. The program is built upon Second Language Acquisition theories and aims to assist ESL learners in higher education by…

Potential of Mobile Learning in Teaching of ESL Academic Writing

Science.gov (United States)

Zaki, Arlina Ahmad; Yunus, Melor Md

2015-01-01

The potentials of mobile learning in teaching academic writing skills for ESL students are explored in this paper. Although there have been studies on MALL to improve writing skills, academic writing was never really touched. Few aspects are covered like the changes in educational technology, defining MALL, identifying issues in academic writing…

The Changing Social Content of ESL Textbooks in the USA.

Science.gov (United States)

Adams, Thomas W.

An analysis of English-as-a-Second-Language (ESL) textbooks published in the United States from the 1950s through the 1980s focuses on incidental but pervasive social messages contained in their content, including restriction to middle class populations and values, stereotyped sex roles, lack of visibility of minorities, negative messages about…

Tuning plasmons layer-by-layer for quantitative colloidal sensing with surface-enhanced Raman spectroscopy.

Science.gov (United States)

Anderson, William J; Nowinska, Kamila; Hutter, Tanya; Mahajan, Sumeet; Fischlechner, Martin

2018-04-19

Surface-enhanced Raman spectroscopy (SERS) is well known for its high sensitivity that emerges due to the plasmonic enhancement of electric fields typically on gold and silver nanostructures. However, difficulties associated with the preparation of nanostructured substrates with uniform and reproducible features limit reliability and quantitation using SERS measurements. In this work we use layer-by-layer (LbL) self-assembly to incorporate multiple functional building blocks of collaborative assemblies of nanoparticles on colloidal spheres to fabricate SERS sensors. Gold nanoparticles (AuNPs) are packaged in discrete layers, effectively 'freezing nano-gaps', on spherical colloidal cores to achieve multifunctionality and reproducible sensing. Coupling between layers tunes the plasmon resonance for optimum SERS signal generation to achieve a 10 nM limit of detection. Significantly, using the layer-by-layer construction, SERS-active AuNP layers are spaced out and thus optically isolated. This uniquely allows the creation of an internal standard within each colloidal sensor to enable highly reproducible self-calibrated sensing. By using 4-mercaptobenzoic acid (4-MBA) as the internal standard adenine concentrations are quantified to an accuracy of 92.6-99.5%. Our versatile approach paves the way for rationally designed yet quantitative colloidal SERS sensors and their use in a variety of sensing applications.

High performance a-IGZO thin-film transistors with mf-PVD SiO2 as an etch-stop-layer

NARCIS (Netherlands)

Nag, M.; Steudel, S.; Bhoolokam, A.; Chasin, A.; Rockele, M.; Myny, K.; Maas, J.; Fritz, T.; Trube, J.; Groeseneken, G.; Heremans, P.

2014-01-01

In this work, we report on high-performance bottom-gate top-contact (BGTC) amorphous-Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with SiO2 as an etch-stop-layer (ESL) deposited by medium frequency physical vapor deposition (mf-PVD). The TFTs show field-effect mobility (μFE) of

Modelling the artic stable boundary layer and its coupling to the surface

NARCIS (Netherlands)

Steeneveld, G.J.; Wiel, van de B.J.H.; Holtslag, A.A.M.

2006-01-01

The impact of coupling the atmosphere to the surface energy balance is examined for the stable boundary layer, as an extension of the first GABLS (GEWEX Atmospheric Boundary-Layer Study) one-dimensional model intercomparison. This coupling is of major importance for the stable boundary-layer

High Reynolds number rough wall turbulent boundary layer experiments using Braille surfaces

Science.gov (United States)

Harris, Michael; Monty, Jason; Nova, Todd; Allen, James; Chong, Min

2007-11-01

This paper details smooth, transitional and fully rough turbulent boundary layer experiments in the New Mexico State high Reynolds number rough wall wind tunnel. The initial surface tested was generated with a Braille printer and consisted of an uniform array of Braille points. The average point height being 0.5mm, the spacing between the points in the span was 0.5mm and the surface consisted of span wise rows separated by 4mm. The wavelength to peak ratio was 8:1. The boundary layer thickness at the measurement location was 190mm giving a large separation of roughness height to layer thickness. The maximum friction velocity was uτ=1.5m/s at Rex=3.8 x10^7. Results for the skin friction co-efficient show that this surface follows a Nikuradse type inflectional curve and that Townsends outer layer similarity hypothesis is valid for rough wall flows with a large separation of scales. Mean flow and turbulence statistics will be presented.

Formation and Characterization of Stacked Nanoscale Layers of Polymers and Silanes on Silicon Surfaces

Science.gov (United States)

Ochoa, Rosie; Davis, Brian; Conley, Hiram; Hurd, Katie; Linford, Matthew R.; Davis, Robert C.

2008-10-01

Chemical surface patterning at the nanoscale is a critical component of chemically directed assembly of nanoscale devices or sensitive biological molecules onto surfaces. Complete and consistent formation of nanoscale layers of silanes and polymers is a necessary first step for chemical patterning. We explored methods of silanizing silicon substrates for the purpose of functionalizing the surfaces. The chemical functionalization, stability, flatness, and repeatability of the process was characterized by use of ellipsometry, water contact angle, and Atomic Force Microscopy (AFM). We found that forming the highest quality functionalized surfaces was accomplished through use of chemical vapor deposition (CVD). Specifically, surfaces were plasma cleaned and hydrolyzed before the silane was applied. A polymer layer less then 2 nm in thickness was electrostatically bound to the silane layer. The chemical functionalization, stability, flatness, and repeatability of the process was also characterized for the polymer layer using ellipsometry, water contact angle, and AFM.

Surface modification of upconverting nanoparticles by layer-by-layer assembled polyelectrolytes and metal ions.

Science.gov (United States)

Palo, Emilia; Salomäki, Mikko; Lastusaari, Mika

2017-12-15

Modificating and protecting the upconversion luminescence nanoparticles is important for their potential in various applications. In this work we demonstrate successful coating of the nanoparticles by a simple layer-by-layer method using negatively charged polyelectrolytes and neodymium ions. The layer fabrication conditions such as number of the bilayers, solution concentrations and selected polyelectrolytes were studied to find the most suitable conditions for the process. The bilayers were characterized and the presence of the desired components was studied and confirmed by various methods. In addition, the upconversion luminescence of the bilayered nanoparticles was studied to see the effect of the surface modification on the overall intensity. It was observed that with selected deposition concentrations the bilayer successfully shielded the particle resulting in stronger upconversion luminescence. The layer-by-layer method offers multiple possibilities to control the bilayer growth even further and thus gives promises that the use of upconverting nanoparticles in applications could become even easier with less modification steps in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of changes in surface layer properties on tire/pavement noise

NARCIS (Netherlands)

Li, M.; Van Keulen, W.; Ceylan, H.; Van de Ven, M.F.C.; Molenaar, A.A.A.

2013-01-01

This paper investigates changes in tire/pavement noise caused by variations in the road surface characteristics. This research is based on the analysis of noise and surface characteristics collected from sections with 25 mm thickness thin layer surfacings in the Netherlands. Investigations are first

What do we know about educating Asian ESL nursing students? A literature review.

Science.gov (United States)

Scheele, Tina Hunter; Pruitt, Rosanne; Johnson, Arlene; Xu, Yu

2011-01-01

Because of cultural differences and language barriers, some Asian nursing students who speak English as a second language (ESL) have not realized their full potential and career goals. Based on an exhaustive search through existing electronic databases in health sciences, this article synthesizes the published literature between 1980 and 2010 on this subgroup of nursing students in four domains: conceptual frameworks, language and communication, support and infrastructure, and instructional strategies. However, some of the classic works were published before 1980. Findings indicate that a body of literature on ESL nursing students has emerged in the last decades, with several limitations. Based on this review, implications for future educational practice and research are elaborated, with an emphasis on an evidence-based approach.

Nanoscale surface modification of Li-rich layered oxides for high-capacity cathodes in Li-ion batteries

Science.gov (United States)

Lan, Xiwei; Xin, Yue; Wang, Libin; Hu, Xianluo

2018-03-01

Li-rich layered oxides (LLOs) have been developed as a high-capacity cathode material for Li-ion batteries, but the structural complexity and unique initial charging behavior lead to several problems including large initial capacity loss, capacity and voltage fading, poor cyclability, and inferior rate capability. Since the surface conditions are critical to electrochemical performance and the drawbacks, nanoscale surface modification for improving LLO's properties is a general strategy. This review mainly summarizes the surface modification of LLOs and classifies them into three types of surface pre-treatment, surface gradient doping, and surface coating. Surface pre-treatment usually introduces removal of Li2O for lower irreversible capacity while surface doping is aimed to stabilize the structure during electrochemical cycling. Surface coating layers with different properties, protective layers to suppress the interface side reaction, coating layers related to structural transformation, and electronic/ionic conductive layers for better rate capability, can avoid the shortcomings of LLOs. In addition to surface modification for performance enhancement, other strategies can also be investigated to achieve high-performance LLO-based cathode materials.

Influence of the surface layer characteristics on the regularities of the cutting process

Directory of Open Access Journals (Sweden)

Krainev Dmitriy V.

2017-01-01

Full Text Available The article considers the influence of the surface layer characteristics on the regularities of the cutting process and the formation of the quality of the surface machined. This effect has been confirmed by the study results of the combined cutting method with advanced plastic deformation (APD. The work estimates the impact of the change in the surface layer properties on the forces and temperature of cutting, stability of the chip formation and quality parameters of the surface machined.

The nanostructure and microstructure of SiC surface layers deposited by MWCVD and ECRCVD

Science.gov (United States)

Dul, K.; Jonas, S.; Handke, B.

2017-12-01

Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) have been used to investigate ex-situ the surface topography of SiC layers deposited on Si(100) by Microwave Chemical Vapour Deposition (MWCVD) -S1,S2 layers and Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) - layers S3,S4, using silane, methane, and hydrogen. The effects of sample temperature and gas flow on the nanostructure and microstructure have been investigated. The nanostructure was described by three-dimensional surface roughness analysis based on digital image processing, which gives a tool to quantify different aspects of surface features. A total of 13 different numerical parameters used to describe the surface topography were used. The scanning electron image (SEM) of the microstructure of layers S1, S2, and S4 was similar, however, layer S3 was completely different; appearing like grains. Nonetheless, it can be seen that no grain boundary structure is present in the AFM images.

Expression of E-selectin ligand-1 (CFR/ESL-1) on hepatic stellate cells: implications for leukocyte extravasation and liver metastasis.

Science.gov (United States)

Antoine, Marianne; Tag, Carmen G; Gressner, Axel M; Hellerbrand, Claus; Kiefer, Paul

2009-02-01

Leukocytes and tumor cells use E-selectin binding ligands to attach to activated endothelial cells expressing E-selectin during inflammation or metastasis. The cysteine-rich fibroblast growth factor receptor (CFR) represents the main E-selectin ligand (ESL-1) on granulocytes and its expression is exclusively modified by alpha(1,3)-fucosyltransferases IV or VII (FucT4 and FucT7). Hepatic stellate cells (HSC) are pericytes of liver sinusoidal endothelial cells. The activation of HSC and transdifferentiation into a myofibroblastic phenotype is involved in the repair of liver tissue injury, liver regeneration and angiogenesis of liver metastases. In the present study, we demonstrated that HSC expressed CFR together with FucT7 and exhibited a functional E-selectin binding activity on their cell surface. Since HSC appear to be oxygen-sensing cells, the expression of E-selectin binding activity was analyzed in HSC under a hypoxic atmosphere. While the expression of the glycoprotein CFR was unaffected by hypoxia, the cell-associated E-selectin binding activity decreased. However, under the same conditions, mRNA expression of the modifying enzyme FucT7 increased. The loss of E-selectin binding activity, therefore, appears to be neither the result of a reduced expression of the modifying transferase nor the expression of the backbone glycoprotein. After the transient transfection of HSC with CFR cDNA, the E-selectin binding activity (ESL-1) was efficiently released into the supernatant. Therefore, we hypothesize that under hypoxia, ESL-1 is shed from activated HSC. Our findings provide a novel perspective on the function of HSC in liver metastasis and inflammatory liver diseases.

Hot zirconium cathode sputtered layers for useful surface modification

International Nuclear Information System (INIS)

Duckworth, R.G.

1986-01-01

It has been found that multilayer zirconium based sputtered coatings can greatly improve the wear properties of a wide variety of mechanical components, machine tools, and metal surfaces. Although a hot (approximately 1000 0 C) cathode is employed, temperature sensitive components can be beneficially treated, and for precision parts a total coating thickness of only 0.5μm is often perfectly effective. Even at the highest coating rates substrate temperatures are below 300 0 C. For the corrosion protection of less well finished surfaces thicker layers are usually required and it is important that relatively stress free layers are produced. The authors employed a variety of tailored zirconium/zirconium nitride/zirconium oxide mixed layers to solve a number of tribological problems for some 5 or 6 years. However, it is only recently that they designed, built, and commissioned rapid cycle, multiple cathode, load-lock plant for economic production of such coatings. This paper provides an introduction to this method of depositing pure zirconium and pure synthetic zirconium nitride films

Applications of Universal Grammar (UG) in the ESL/EFL Classroom

Science.gov (United States)

Kirkwold, Lorne O.

2007-01-01

The article proposes Stern's (1983) framework for classifying issues related to instruction in order to ascertain the relevance of Universal Grammar (UG) in the ESL/EFL classroom. Discussed in this article, particularly as UG pertains to them, are issues related to: (a) L1 transfer; (b) teaching rules and giving error correction versus presenting…

The Effects of Using Multimodal Approaches in Meaning-Making of 21st Century Literacy Texts Among ESL Students in a Private School in Malaysia

Directory of Open Access Journals (Sweden)

Malini Ganapathy

2016-04-01

Full Text Available In today’s globalised digital era, students are inevitably engaged in various multimodal texts due to their active participation in social media and frequent usage of mobile devices on a daily basis. Such daily activities advocate the need for a transformation in the teaching and learning of ESL lessons in order to promote students’ capabilities in making meaning of different literacy texts which students come across in their ESL learning activities. This paper puts forth the framework of Multimodality in the restructuring of the teaching and learning of ESL with the aim of investigating its effects and students perspectives on the use of multimodal approaches underlying the Multiliteracies theory. Using focus group interviews, this qualitative case study examines the effectiveness of ESL teaching and learning using the Multimodal approaches on literacy in meaning-making among 15 students in a private school in Penang, Malaysia. The results confirm the need to reorientate the teaching and learning of ESL with the focus on multimodal pedagogical practices as it promotes positive learning outcomes among students. The implications of this study suggest that the multimodal approaches integrated in the teaching and learning of ESL have the capacity to promote students’ autonomy in learning, improve motivation to learn and facilitate various learning styles. Keywords: Multimodal Approaches; Multiliteracies; Monomodal; Flipped Classroom; Literacy; Multimodal texts; Ipad

Laser-induced oxidation of titanium substrate: Analysis of the physicochemical structure of the surface and sub-surface layers

Energy Technology Data Exchange (ETDEWEB)

Antończak, Arkadiusz J., E-mail: arkadiusz.antonczak@pwr.edu.pl [Laser and Fiber Electronics Group, Faculty of Electrical Engineering, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland); Skowroński, Łukasz; Trzcinski, Marek [Institute of Mathematics and Physics, University of Technology and Life Sciences, Kaliskiego 7, 85-789 Bydgoszcz (Poland); Kinzhybalo, Vasyl V. [Wroclaw Research Centre EIT+, Stabłowicka 147, 54-066 Wrocław (Poland); Institute of Low Temperature and Structure Research, Okólna 2, 50-422 Wrocław (Poland); Łazarek, Łukasz K.; Abramski, Krzysztof M. [Laser and Fiber Electronics Group, Faculty of Electrical Engineering, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland)

2015-01-15

Highlights: • Chemical structure of the films induced by laser on titanium surface was analyzed. • It was shown that outer layer of this films consist of oxides doped with nitrogen. • The optical properties of the laser-induced oxynitride films were characterized. • We found that the films demonstrated significant absorption in the band of 300–580 nm. • The morphology of the layers as a function of the laser fluence was investigated. - Abstract: This paper presents the results of the analysis of the complex chemical structure of the layers made on titanium in the process of the heating of its surfaces in an atmospheric environment, by irradiating samples with a nanosecond-pulsed laser. The study was carried out for electroplated, high purity, polycrystalline titanium substrates using a Yb:glass fiber laser. All measurements were made for samples irradiated in a broad range of accumulated fluence, below the ablation threshold. It has been determined how the complex index of refraction of both the oxynitride layers and the substrate vary as a function of accumulated laser fluence. It was also shown that the top layer of the film produced on titanium, which is transparent, is not a pure TiO{sub 2} as had been supposed before. The XPS and XRD analyses confirmed the presence of nitrogen compounds and the existence of nonstoichiometric compounds. By sputtering of the sample's surface using an Ar{sup +} ion gun, the changes in the concentration of individual elements as a function of the layer's cross-section were determined. Lastly, an analysis of the surface morphology has also been carried out, explaining why the layers crack and exfoliate from their substrate.

Investigating Nigerian primary school teachers’ preparedness to adopt personal response system in ESL classroom

Directory of Open Access Journals (Sweden)

Alaba Olaoluwakotansibe Agbatogun

2012-03-01

Full Text Available This study investigated the extent to which computer literacy dimensions (computer general knowledge, documents and documentations, communication and surfing as well as data inquiry, computer use and academic qualification as independent variables predicted primary school teachers’ attitude towards the integration of Personal Response System in English as a second language (ESL classroom. Seventeen (17 Nigerian primary school teachers trained on why and how to effectively use Personal Response System (PRS in ESL classrooms was the sample for the study. Data for the study were gathered through the use of Clickers Attitude Questionnaire (CAQ, Teachers’ Computer Literacy Questionnaire (TCLQ and Computer Use Questionnaire (CUQ. Descriptive statistics such as simple percentage, mean and standard deviation, and inferential statistics such as Pearson Product Moment Correlation Coefficient, and Multiple regression were used for data analysis at 0.05 significance level. The results show that the teachers’ computer literacy was more in the areas of documents and documentation as well as communication and surfing than in general knowledge and data inquiry. Further findings of the study indicated that general computer knowledge, documents and documentation, communication and surfing, and data inquiry combined to contribute to the prediction of teachers’ attitude towards the integration of PRS. Relatively, documents and documentation dimension was the potent predictor, while data inquiry was not a significant predictor of the outcome variable. Similarly, computer use, computer literacy and academic qualification jointly contributed to the prediction of the teachers’ attitude towards the integration of PRS in ESL classroom. Meanwhile, computer use made the most significant contribution to the prediction of teachers’ attitude towards PRS integration, while academic qualification did not make any significant contribution to the teachers’ attitude

Investigating Nigerian Primary School Teachers’ Preparedness to Adopt Personal Response System in ESL Classroom

Directory of Open Access Journals (Sweden)

Alaba Olaoluwakotansibe Agbatogun

2012-03-01

Full Text Available This study investigated the extent to which computer literacy dimensions (computer general knowledge, documents and documentations, communication and surfing as well as data inquiry, computer use and academic qualification as independent variables predicted primary school teachers’ attitude towards the integration of Personal Response System in English as a second language (ESL classroom. Seventeen (17 Nigerian primary school teachers trained on why and how to effectively use Personal Response System (PRS in ESL classrooms was the sample for the study. Data for the studywere gathered through the use of Clickers Attitude Questionnaire (CAQ, Teachers’ Computer Literacy Questionnaire (TCLQ and Computer Use Questionnaire (CUQ. Descriptive statistics such as simplepercentage, mean and standard deviation, and inferential statistics such as Pearson Product Moment Correlation Coefficient, and Multiple regression were used for data analysis at 0.05 significance level.The results show that the teachers’ computer literacy was more in the areas of documents and documentation as well as communication and surfing than in general knowledge and data inquiry. Further findings of the study indicated that general computer knowledge, documents anddocumentation, communication and surfing, and data inquiry combined to contribute to the prediction of teachers’ attitude towards the integration of PRS. Relatively, documents and documentation dimension was the potent predictor, while data inquiry was not a significant predictor of the outcome variable. Similarly, computer use, computer literacy and academic qualification jointly contributed to the prediction of the teachers’ attitude towards the integration of PRS in ESL classroom. Meanwhile, computer use made the most significant contribution to the prediction of teachers’ attitude towards PRS integration, while academic qualification did not make any significantcontribution to the teachers’ attitude

Abrasive wear mechanisms and surface layer structure of refractory materials after mechanical working

International Nuclear Information System (INIS)

Milman, Y.V.; Lotsko, D.V.

1989-01-01

The mechanisms of abrasive wear and surface layer structure formation after different kinds of mechanical working are considered in terms of fracture and plastic deformation mechanisms for various refractory materials. The principles for classification of abrasive wear mechanisms are proposed, the four types of wear mechanisms are distinguished for various combinations of fractures and plastic deformation types. The concept of characteristic deformation temperature t * (knee temperature) is used. Detailed examples are given of investigating the surface layer structures in grinded crystals of sapphire and molybdenum. The amorphisation tendency of the thinnest surface layer while mechanical polishing is discussed separately. 19 refs., 11 figs., 2 tabs. (Author)

Strategies to Help ESL Students Improve their Communicative Competence and Class Participation: A Study in a Middle School

Directory of Open Access Journals (Sweden)

Claudia Gómez Palacio

2010-12-01

Full Text Available This article examines a qualitative study carried out at a middle school in North Carolina, the United States of America. The main purpose of the study was to find effective strategies that teachers can use to help ESL students improve their speaking skills and class participation. Results indicated that both communicative and social strategies as well as exposure to independent reading help ESL students improve their communicative skills and class participation.

Atomic Layer-Deposited TiO2 Coatings on NiTi Surface

Science.gov (United States)

Vokoun, D.; Racek, J.; Kadeřávek, L.; Kei, C. C.; Yu, Y. S.; Klimša, L.; Šittner, P.

2018-02-01

NiTi shape-memory alloys may release poisonous Ni ions at the alloys' surface. In an attempt to prepare a well-performing surface layer on an NiTi sample, the thermally grown TiO2 layer, which formed during the heat treatment of NiTi, was removed and replaced with a new TiO2 layer prepared using the atomic layer deposition (ALD) method. Using x-ray photoelectron spectroscopy, it was found that the ALD layer prepared at as low a temperature as 100 °C contained Ti in oxidation states + 4 and + 3. As for static corrosion properties of the ALD-coated NiTi samples, they further improved compared to those covered by thermally grown oxide. The corrosion rate of samples with thermally grown oxide was 1.05 × 10-5 mm/year, whereas the corrosion rate of the ALD-coated samples turned out to be about five times lower. However, cracking of the ALD coating occurred at about 1.5% strain during the superelastic mechanical loading in tension taking place via the propagation of a localized martensite band.

Free surface simulation of a two-layer fluid by boundary element method

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Weoncheol Koo

2010-09-01

Full Text Available A two-layer fluid with free surface is simulated in the time domain by a two-dimensional potential-based Numerical Wave Tank (NWT. The developed NWT is based on the boundary element method and a leap-frog time integration scheme. A whole domain scheme including interaction terms between two layers is applied to solve the boundary integral equation. The time histories of surface elevations on both fluid layers in the respective wave modes are verified with analytic results. The amplitude ratios of upper to lower elevation for various density ratios and water depths are also compared.

X-ray study of surface layers of tungsten monocrystals after electroerosion machining

International Nuclear Information System (INIS)

Aleshina, S.A.; Baranov, Yu.V.; Smirnov, I.S.; Marchuk, A.I.

1981-01-01

The presence of polycrystal surface layer, approximately 10 μm thick in subjacent layers and the presence of highly developed block structure which is the result of high-temperature effect of electroerosion machining are detected. Angles of disorientation between blocks, which constitute tens of angular minutes, are evaluated using the method of X-ray topography. According to broadening of profile of X-ray diffraction lines analysis of fine crystal structure of the surface layers is conducted. It is shown that the broadening of diffraction lines is mainly connected with the presence of coherent scat-- tering regions

Formation of Pentacene wetting layer on the SiO2 surface and charge trap in the wetting layer

International Nuclear Information System (INIS)

Kim, Chaeho; Jeon, D.

2008-01-01

We studied the early-stage growth of vacuum-evaporated pentacene film on a native SiO 2 surface using atomic force microscopy and in-situ spectroscopic ellipsometry. Pentacene deposition prompted an immediate change in the ellipsometry spectra, but atomic force microscopy images of the early stage films did not show a pentacene-related morphology other than the decrease in the surface roughness. This suggested that a thin pentacene wetting layer was formed by pentacene molecules lying on the surface before the crystalline islands nucleated. Growth simulation based on the in situ spectroscopic ellipsometry spectra supported this conclusion. Scanning capacitance microscopy measurement indicated the existence of trapped charges in the SiO 2 and pentacene wetting layer

Effect of Mo Ion Implantation on Stability of Nanocrystalline Copper Surface Layers

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XI Yang

2016-08-01

Full Text Available The surface of pure copper was modified using the surface mechanical attrition treatment (SMAT method, and molybdenum ions were implanted in the nanosurface using a metal vapor vacuum arc (MEVVA. The results of the SMAT were observed by optical microscopy (OM, X-ray diffraction (XRD and scanning electron microscopy (SEM. An obvious nanocrystalline layer and a deformation region exist on the surface. The size of the nanocrystalline layer was characterized using atomic force microscopy (AFM. The results indicate remarkable suppression on grain size, the nanocrystalline layer grows to 163nm after annealing and reduces to only 72nm due to the Mo ion implantation. In addition, the hardness of the topmost surface of the material is 3.5 times that of the SMATed copper, which is about 7 times of the value of the matrix. The above improvements most likely result from the dispersion of the Mo ions and the reactions of the crystal defects due to the SMAT and ion implantation.

Air Entrainment and Surface Ripples in a Turbulent Ship Hull Boundary Layer

Science.gov (United States)

Masnadi, Naeem; Erinin, Martin; Duncan, James H.

2017-11-01

The air entrainment and free-surface fluctuations caused by the interaction of a free surface and the turbulent boundary layer of a vertical surface-piercing plate is studied experimentally. In this experiment, a meter-wide stainless steel belt travels horizontally in a loop around two rollers with vertically oriented axes. This belt device is mounted inside a large water tank with the water level set just below the top edge of the belt. The belt, rollers, and supporting frame are contained within a sheet metal box to keep the device dry except for one 6-meter-long straight test section. The belt is accelerated suddenly from rest until reaching constant speed in order to create a temporally evolving boundary layer analogous to the spatially evolving boundary layer that would exist along a surface-piercing towed flat plate. Surface ripples are measured using a cinematic laser-induced fluorescence technique with the laser sheet oriented parallel or normal to the belt surface. Air entrainment events and bubble motions are recorded from underneath the water surface using a stereo imaging system. Measurements of small bubbles, that tend to stay submerged for a longer time, are planned via a high-speed digital in-line holographic system. The support of the Office of Naval Research is gratefully acknowledged.

Apparatus for plasma surface treating and preparation of membrane layers

NARCIS (Netherlands)

1990-01-01

An apparatus suitable for plasma surface treating (e.g., forming a membrane layer on a substrate surface) comprises a plasma generation section which is operable at least at substantially atmospheric pressure and is in communication via at least one plasma inlet (e.g., a nozzle) with an enclosed

On the sensitivity of mesoscale models to surface-layer parameterization constants

Science.gov (United States)

Garratt, J. R.; Pielke, R. A.

1989-09-01

The Colorado State University standard mesoscale model is used to evaluate the sensitivity of one-dimensional (1D) and two-dimensional (2D) fields to differences in surface-layer parameterization “constants”. Such differences reflect the range in the published values of the von Karman constant, Monin-Obukhov stability functions and the temperature roughness length at the surface. The sensitivity of 1D boundary-layer structure, and 2D sea-breeze intensity, is generally less than that found in published comparisons related to turbulence closure schemes generally.

Apology Strategies of Iranian ESL Students

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Haleh Parsa

2015-01-01

Full Text Available The main focus of this study, which is of the most important and most frequent speech acts used in multicultural settings, is the speech act of apology. It probes native Persian-speaking ESL university students’ apology and non-apology strategies based on Cohen and Olshtain’s (1981 frame work to evince variations ascribed to gender, mother tongue, and culture. The results of this survey reveal that Iranian male and female respondents use different percentages of apology and non-apology strategies. Considering significance levels, in general, except for a few strategies, there is no statistically significant difference between the groups considering the number and type of strategies used.

An Argument against Using Standardized Test Scores for Placement of International Undergraduate Students in English as a Second Language (ESL) Courses

Science.gov (United States)

Kokhan, Kateryna

2013-01-01

Development and administration of institutional ESL placement tests require a great deal of financial and human resources. Due to a steady increase in the number of international students studying in the United States, some US universities have started to consider using standardized test scores for ESL placement. The English Placement Test (EPT)…

Torsional surface waves in an inhomogeneous layer over a gravitating anisotropic porous half-space

International Nuclear Information System (INIS)

Gupta, Shishir; Pramanik, Abhijit

2015-01-01

The present work aims to deal with the propagation of torsional surface wave in an inhomogeneous layer over a gravitating anisotropic porous half space. The inhomogeneous layer exhibits the inhomogeneity of quadratic type. In order to show the effect of gravity the equation for the velocity of torsional wave has been obtained. It is also observed that for a layer over a homogeneous half space without gravity, the torsional surface wave does not propagate. An attempt is also made to assess the possible propagation of torsional surface waves in that medium in the absence of the upper layer. The effects of inhomogeneity factors and porosity on the phase velocity are depicted by means of graphs. (paper)

Distribution of Articles in Written Composition among Malaysian ESL Learners

Science.gov (United States)

Rahim, Mia Emily Abdul; Rahim, Emma Marini Abdul; Ning, Chia Han

2013-01-01

The study aimed to investigate the distribution patterns of the English grammar articles (a, an, and the) as well as the distributions of their colligation patterns in written compositions of English among Malaysian ESL learners. This paper reports the results of a corpus-based study on articles used by these learners. The method used in this…

FDTD Investigation on Electromagnetic Scattering from Two-Layered Rough Surfaces under UPML Absorbing Condition

International Nuclear Information System (INIS)

Juan, Li; Li-Xin, Guo; Hao, Zeng

2009-01-01

Electromagnetic scattering from one-dimensional two-layered rough surfaces is investigated by using finite-difference time-domain algorithm (FDTD). The uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. The rough surfaces are characterized with Gaussian statistics for the height and the autocorrelation function. The angular distribution of bistatic scattering coefficient from single-layered perfect electric conducting and dielectric rough surface is calculated and it is in good agreement with the numerical result with the conventional method of moments. The influence of the relative permittivity, the incident angle, and the correlative length of two-layered rough surfaces on the bistatic scattering coefficient with different polarizations are presented and discussed in detail. (fundamental areas of phenomenology (including applications))

The Health Literacy and ESL study: a community-based intervention for Spanish-speaking adults.

Science.gov (United States)

Soto Mas, Francisco; Ji, Ming; Fuentes, Brenda O; Tinajero, Josefina

2015-04-01

Although Hispanics have a documented high risk of limited health literacy, there is a scarcity of research with this population group, and particularly with Hispanic immigrants who generally confront language barriers that have been related to low health literacy. The National Action Plan to Improve Health Literacy identified community-based English-language instruction as a strategy that can facilitate a health literate society. However, the literature lacks discussion on this type of intervention. This randomized control trial aimed to test the feasibility of using conventional English-as-a-second-language (ESL) instruction for improving health literacy among Spanish-speaking adults. Objectives included the development, implementation, and evaluation of a health literacy/ESL curriculum. The Test of Functional Health Literacy in Adults (TOFHLA) in English was used to assess health literacy levels. Analyses included independent sample t test, chi-square, and multiple linear regression. A total of 155 people participated. Results showed a significantly higher increase in the TOFHLA posttest score in the intervention group (p = .01), and noticeable differences in health literacy levels between groups. Results indicate that ESL constitutes a promising venue for improving health literacy among Spanish-speaking adults. Incorporating health literacy-related content may provide additional benefits.

The Health Literacy and ESL Study: A Community-Based Intervention for Spanish-Speaking Adults

Science.gov (United States)

MAS, FRANCISCO SOTO; JI, MING; FUENTES, BRENDA O.; TINAJERO, JOSEFINA

2015-01-01

Although Hispanics have a documented high risk of limited health literacy, there is a scarcity of research with this population group, and particularly with Hispanic immigrants who generally confront language barriers that have been related to low health literacy. The National Action Plan to Improve Health Literacy identified community-based English-language instruction as a strategy that can facilitate a health literate society. However, the literature lacks discussion on this type of intervention. This randomized control trial aimed to test the feasibility of using conventional English-as-a-second-language (ESL) instruction for improving health literacy among Spanish-speaking adults. Objectives included the development, implementation, and evaluation of a health literacy/ESL curriculum. The Test of Functional Health Literacy in Adults (TOFHLA) in English was used to assess health literacy levels. Analyses included independent sample t test, chi-square, and multiple linear regression. A total of 155 people participated. Results showed a significantly higher increase in the TOFHLA posttest score in the intervention group (p = .01), and noticeable differences in health literacy levels between groups. Results indicate that ESL constitutes a promising venue for improving health literacy among Spanish-speaking adults. Incorporating health literacy-related content may provide additional benefits. PMID:25602615

Wave-Breaking Turbulence in the Ocean Surface Layer

Science.gov (United States)

2016-06-01

2004) used direct numerical simulation ( DNS ) to show that a single breaking wave can energize the surface layer for more than 50 wave periods, and...1941: Dissipation of energy in the locally isotropic turbulence. Dokl. Akad. Nauk SSR, 30, 301–305. Kukulka, T., and K. Brunner, 2015: Passive

Surface state of GaN after rapid-thermal-annealing using AlN cap-layer

Energy Technology Data Exchange (ETDEWEB)

El-Zammar, G., E-mail: georgio.elzammar@univ-tours.fr [Université François Rabelais, Tours, GREMAN, CNRS UMR 7347, 10 rue Thalès de Milet CS 97155, 37071 Tours Cedex 2 (France); Khalfaoui, W. [Université François Rabelais, Tours, GREMAN, CNRS UMR 7347, 10 rue Thalès de Milet CS 97155, 37071 Tours Cedex 2 (France); Oheix, T. [Université François Rabelais, Tours, GREMAN, CNRS UMR 7347, 10 rue Thalès de Milet CS 97155, 37071 Tours Cedex 2 (France); STMicroelectronics, 10 rue Thalès de Milet CS 97155, 37071 Tours Cedex 2 (France); Yvon, A.; Collard, E. [STMicroelectronics, 10 rue Thalès de Milet CS 97155, 37071 Tours Cedex 2 (France); Cayrel, F.; Alquier, D. [Université François Rabelais, Tours, GREMAN, CNRS UMR 7347, 10 rue Thalès de Milet CS 97155, 37071 Tours Cedex 2 (France)

2015-11-15

Graphical abstract: Surface state of a crack-free AlN cap-layer reactive sputtered on GaN and annealed at high temperature showing a smooth, pit-free surface. - Highlights: • We deposit a crystalline AlN layer by reactive magnetron sputtering on GaN. • We show the effect of deposition parameters of AlN by reactive magnetron sputtering on the quality of the grown layer. • We demonstrate the efficiency of double cap-layer for GaN protection during high temperature thermal treatments. • We show an efficient selective etch of AlN without damaging GaN surface. - Abstract: Critical issues need to be overcome to produce high performance Schottky diodes on gallium nitride (GaN). To activate dopant, high temperature thermal treatments are required but damage GaN surface where hexagonal pits appear and prevent any device processing. In this paper, we investigated the efficiency of cap-layers on GaN during thermal treatments to avoid degradation. Aluminum nitride (AlN) and silicon oxide (SiO{sub x}) were grown on GaN by direct current reactive magnetron sputtering and plasma-enhanced chemical vapor deposition, respectively. AlN growth parameters were studied to understand their effect on the grown layers and their protection efficiency. Focused ion beam was used to measure AlN layer thickness. Crystalline quality and exact composition were verified using X-ray diffraction and energy dispersive X-ray spectroscopy. Two types of rapid thermal annealing at high temperatures were investigated. Surface roughness and pits density were evaluated using atomic force microscopy and scanning electron microscopy. Cap-layers wet etching was processed in H{sub 3}PO{sub 4} at 120 °C for AlN and in HF (10%) for SiO{sub x}. This work reveals effective protection of GaN during thermal treatments at temperatures as high as 1150 °C. Low surface roughness was obtained. Furthermore, no hexagonal pit was observed on the surface.

Surface metal standards produced by ion implantation through a removable layer

International Nuclear Information System (INIS)

Schueler, B.W.; Granger, C.N.; McCaig, L.; McKinley, J.M.; Metz, J.; Mowat, I.; Reich, D.F.; Smith, S.; Stevie, F.A.; Yang, M.H.

2003-01-01

Surface metal concentration standards were produced by ion implantation and investigated for their suitability to calibrate surface metal measurements by secondary ion mass spectrometry (SIMS). Single isotope implants were made through a 100 nm oxide layer on silicon. The implant energies were chosen to place the peak of the implanted species at a depth of 100 nm. Subsequent removal of the oxide layer was used to expose the implant peak and to produce controlled surface metal concentrations. Surface metal concentration measurements by time-of-flight SIMS (TOF-SIMS) with an analysis depth of 1 nm agreed with the expected surface concentrations of the implant standards with a relative mean standard deviation of 20%. Since the TOF-SIMS relative sensitivity factors (RSFs) were originally derived from surface metal measurements of surface contaminated silicon wafers, the agreement implies that the implant standards can be used to measure RSF values. The homogeneity of the surface metal concentration was typically <10%. The dopant dose remaining in silicon after oxide removal was measured using the surface-SIMS protocol. The measured implant dose agreed with the expected dose with a mean relative standard deviation of 25%

Authentic ESL Spoken Materials: Soap Opera and Sitcom versus Natural Conversation

Science.gov (United States)

Al-Surmi, Mansoor Ali

2012-01-01

TV shows, especially soap operas and sitcoms, are usually considered by ESL practitioners as a source of authentic spoken conversational materials presumably because they reflect the linguistic features of natural conversation. However, practitioners might be faced with the dilemma of how to evaluate whether such conversational materials reflect…

Cohesion Features in ESL Reading: Comparing Beginning, Intermediate and Advanced Textbooks

Science.gov (United States)

Plakans, Lia; Bilki, Zeynep

2016-01-01

This study of English as a second language (ESL) reading textbooks investigates cohesion in reading passages from 27 textbooks. The guiding research questions were whether and how cohesion differs across textbooks written for beginning, intermediate, and advanced second language readers. Using a computational tool called Coh-Metrix, textual…

Cu and Cu(Mn) films deposited layer-by-layer via surface-limited redox replacement and underpotential deposition

Energy Technology Data Exchange (ETDEWEB)

Fang, J.S., E-mail: jsfang@nfu.edu.tw [Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan (China); Sun, S.L. [Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan (China); Cheng, Y.L. [Department of Electrical Engineering, National Chi-Nan University, Nan-Tou 54561, Taiwan (China); Chen, G.S.; Chin, T.S. [Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan (China)

2016-02-28

Graphical abstract: - Abstract: The present paper reports Cu and Cu(Mn) films prepared layer-by-layer using an electrochemical atomic layer deposition (ECALD) method. The structure and properties of the films were investigated to elucidate their suitability as Cu interconnects for microelectronics. Previous studies have used primarily a vacuum-based atomic layer deposition to form a Cu metallized film. Herein, an entirely wet chemical process was used to fabricate a Cu film using the ECALD process by combining underpotential deposition (UPD) and surface-limited redox replacement (SLRR). The experimental results indicated that an inadequate UPD of Pb affected the subsequent SLRR of Cu and lead to the formation of PbSO{sub 4}. A mechanism is proposed to explain the results. Layer-by-layer deposition of Cu(Mn) films was successfully performed by alternating the deposition cycle-ratios of SLRR-Cu and UPD-Mn. The proposed self-limiting growth method offers a layer-by-layer wet chemistry-based deposition capability for fabricating Cu interconnects.

Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

Directory of Open Access Journals (Sweden)

Matthias J. Mayser

2014-06-01

Full Text Available Some plants and animals feature superhydrophobic surfaces capable of retaining a layer of air when submerged under water. Long-term air retaining surfaces (Salvinia-effect are of high interest for biomimetic applications like drag reduction in ship coatings of up to 30%. Here we present a novel method for measuring air volumes and air loss under water. We recorded the buoyancy force of the air layer on leaf surfaces of four different Salvinia species and on one biomimetic surface using a highly sensitive custom made strain gauge force transducer setup. The volume of air held by a surface was quantified by comparing the buoyancy force of the specimen with and then without an air layer. Air volumes retained by the Salvinia-surfaces ranged between 0.15 and 1 L/m2 depending on differences in surface architecture. We verified the precision of the method by comparing the measured air volumes with theoretical volume calculations and could find a good agreement between both values. In this context we present techniques to calculate air volumes on surfaces with complex microstructures. The introduced method also allows to measure decrease or increase of air layers with high accuracy in real-time to understand dynamic processes.

Study on mechanics of driving drum with superelastic convexity surface covering-layer structure

Energy Technology Data Exchange (ETDEWEB)

Xiao, L.J.; Sui, X.H.; Miao, D.J. [Shandong University of Science & Technology, Qingdao (China)

2008-09-15

Belt conveyor is one of the main transport equipment in coal mine and the driving drum is its key part. With the method of bionic design, the mushroom morphological structure is applied to the design of covering-layer structure of driving drum surface of belt conveyor. Superelastic rubber with large deformation is adopted as the covering-layer material. Nonlinear constitutive model of rubber, which is of superelasticity and large deformation, is established. The stress states and deformation principles of driving drums including both bionic covering-layer and common covering-layer are obtained by static intensity analysis with Finite Element Analysis (FEA) software ANSYS. The values of the stress and strain on the driving drum surface are gotten and the dangerous area is determined. FEA results show that the superelastic convexity surface structure can enlarge the contact area between the driving drum and viscoelastic belt. The results also show that in comparison with common driving drum, the bionic surface driving drum can not only increase the friction coefficient between drum and belt but also prolong its service life.

Structure and Construction Assessment of the Surface Layer of Hardfaced Coating after Friction

Directory of Open Access Journals (Sweden)

Krzysztof Dziedzic

2017-09-01

Full Text Available The paper presents an analysis of the surface layer of Fe-Mn-C-B-Si-Ni-Cr alloy coating after friction with C45 steel. The coatings were obtained by arc welding (GMA. Flux-cored wires were used as a welding material. The flux-cored wires had a diameter of 2,4 mm. The tribological assessment was performed with the Amsler tribotester under dry friction conditions at unit pressures 10 MPa. The use of XPS spectroscopy allowed deep profile analysis of the surface layer. Based on the obtained results developed model of the surface layer for friction couple, hardfaced coating obtained from Fe-Mn-C-B-Si-Ni-Cr alloy – C45 steel. It was observed that the operational surface layer (OSL of hardfaced coatings contained oxides (B2O3, SiO2, NiO, Cr2O3, FeO, Fe3O4, Fe2O3, carbides (Fe3C, Cr7C3 and borides (FeB, Fe2B.

Effects of plasma cleaning of the Cu seed layer surface on Cu electroplating

International Nuclear Information System (INIS)

O, Jun Hwan; Lee, Seong Wook; Kim, Jae Bum; Lee, Chong Mu

2001-01-01

Effects of plasma pretreatment to Cu seed/tantalum nitride (TaN)/ borophosphosilicate glass (BPSG) samples on copper (Cu) electroplating were investigated. Copper seed layers were deposited by magnetron sputtering onto tantalum nitride barrier layers before electroplating copper in the forward pulsed mode. The Cu seed layer was cleaned by plasma H 2 and N 2 prior to electroplating a copper film. Cu films electroplated on the copper seed layer with plasma pretreatment showed better electrical and physical properties such as electrical resistivities, surface morphologies, levels of impurities, adhesion and surface roughness than those without plasma pretreatment. It is shown that carbon and metal oxide contaminants at the sputtered Cu seed/TaN surface could be effectively removed by plasma H 2 cleaning. The degree of the (111) prefered orientation of the Cu film with plasma H 2 pretreatment is as high as pulse plated Cu film without plasma pretreatment. Also, plasma H 2 precleaning is more effective in enhancing the Cu electroplating properties onto the Cu seed layer than plasma N 2 precleaning

Microbial biodiversity, quality and shelf life of microfiltered and pasteurized extended shelf life (ESL) milk from Germany, Austria and Switzerland.

Science.gov (United States)

Schmidt, Verena S J; Kaufmann, Veronika; Kulozik, Ulrich; Scherer, Siegfried; Wenning, Mareike

2012-03-01

Information on factors limiting the shelf life of extended shelf life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4 °C, 8 °C and 10 °C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of shelf life. It was observed that microfiltration decreased the microbial loads by 5-6 log₁₀ units to lower than 1 CFU/mL. However, bacterial counts at the end of shelf life were extremely variable and ranged between ESL treatment, causing stochastic variations of initial species distributions in individual packages. This would result in the development of significantly different bacterial populations during cold storage, including the occasional development of high numbers of pathogenic species such as B. cereus or Acinetobacter. Copyright © 2011 Elsevier B.V. All rights reserved.

Concordancers and Dictionaries as Problem-Solving Tools for ESL Academic Writing

Science.gov (United States)

Yoon, Choongil

2016-01-01

The present study investigated how 6 Korean ESL graduate students in Canada used a suite of freely available reference resources, consisting of Web-based corpus tools, Google search engines, and dictionaries, for solving linguistic problems while completing an authentic academic writing assignment in English. Using a mixed methods design, the…

A Quantitative Investigation of ESL Teacher Knowledge in Australian Adult Education

Science.gov (United States)

Yazdanpanah, Lilly K.

2015-01-01

English as a second language (ESL) teaching is partly a thinking process in which teacher knowledge plays a pivotal role in making instructional choices (Breen, Hird, Milton, Oliver, & Thwaite, 2001). The present study contributes to understandings of teacher knowledge by exploring the types of knowledge, which practicing teachers value in…

Integrating Social Networking Tools into ESL Writing Classroom: Strengths and Weaknesses

Science.gov (United States)

Yunus, Melor Md; Salehi, Hadi; Chenzi, Chen

2012-01-01

With the rapid development of world and technology, English learning has become more important. Teachers frequently use teacher-centered pedagogy that leads to lack of interaction with students. This paper aims to investigate the advantages and disadvantages of integrating social networking tools into ESL writing classroom and discuss the ways to…

Self-Questioning and Prose Comprehension: A Sample Case of ESL Reading.

Science.gov (United States)

Miciano, Remedios Z.

2002-01-01

Report on an experiment to discover if self-questioning as a reading strategy would help Filipino ESL students improve comprehension of English prose texts. Concludes that self-questioning as a strategy does not significantly affect comprehension despite the number and types of questions asked. (Contains 4 tables and 25 references.) (WFA)

System for removing contaminated surface layers

International Nuclear Information System (INIS)

Yoshikawa, Kozo.

1987-04-01

The object of the present invention is to offer a new type of useful decontamination system, with which the contaminated surface layers can be removed effectively by injection of such solid microparticles. Liquid carbon dioxide is passed from a liquid carbon dioxide tank via the carbon dioxide supply line into the system for injecting solid carbon dioxide particles. Part of the liquid carbon dioxide introduced into the system is converted to solid carbon dioxide particles by the temperature drop resulting from adiabatic expansion in the carbon dioxide expansion space of the injection system. The solid carbon dioxide particles reach the injection nozzle, which is connected through the expansion space. The carbon dioxide microparticles are further cooled and accelerated by nitrogen gas injected from the nitrogen gas nozzle at the tip of the nitrogen gas supply line, which is connected to a liquid nitrogen tank. The cooled and accelerated solid carbon dioxide microparticles are injected from the injection nozzle for the solid carbon dioxide and directed against the contaminated surface to be cleaned, and, as a result, the surface contamination is removed

Surface pressure drag for hydrostatic two-layer flow over axisymmetric mountains

Energy Technology Data Exchange (ETDEWEB)

Leutbecher, M.

2000-07-01

The effect of partial reflections on surface pressure drag is investigated for hydrostatic gravity waves in two-layer flow with piecewise constant buoyancy frequency. The variation of normalized surface pressure drag with interface height is analyzed for axisymmetric mountains. The results are compared with the familiar solution for infinitely long ridges. The drag for the two-layer flow is normalized with the drag of one-layer flow, which has the buoyancy frequency of the lower layer. An analytical expression for the normalized drag of axisymmetric mountains is derived from linear theory of steady flow. Additionally, two-layer flow over finite-height axisymmetric mountains is simulated numerically for flow with higher stability in the upper layer. The temporal evolution of the surface pressure drag is examined in a series of experiments with different interface and mountain heights. The focus is on the linear regime and the nonlinear regime of nonbreaking gravity waves. The dispersion of gravity waves in flow over isolated mountains prevents that the entire wave spectrum is in resonance at the same interface height, which is the case in hydrostatic flow over infinitely long ridges. In consequence, the oscillation of the normalized drag with interface height is smaller for axisymmetric mountains than for infinitely long ridges. However, even for a reflection coefficient as low as 1/3 the drag of an axisymmetric mountain can be amplified by 50% and reduced by 40%. The nonlinear drag becomes steady in the numerical experiments in which no wave breaking occurs. The steady state nonlinear drag agrees quite well with the prediction of linear theory if the linear drag is computed for a slightly lowered interface. (orig.)

Influence of Speech Anxiety on Oral Communication Skills among ESL/EFL Learners

Directory of Open Access Journals (Sweden)

Said Muhammad Khan

2015-12-01

Full Text Available The realization of speech anxiety among ESL/EFL learners is important. Once understood, these feelings of fear or nervousness may be relieved and the desired objectives of learning the target language may be achieved.  The study has attempted to measure the level of anxiety among ESL/EFL learners at HITEC University, Taxila, Pakistan. The current research has arrived at the conclusion that the target population is highly anxious in situation where they are required to speak English. The findings show that sources such as pedagogical, psychological, socio-economic, linguistic and cultural generate anxiety among the EFL learners. The study has suggested variety of strategies to treat anxiety in the academic context. It was found that communicative approach in classroom may be helpful in minimizing the negative impact of anxiety among language learners. Keywords:  speech anxiety, communicative approach, communication apprehension, FLA

Steady ablation on the surface of a two-layer composite

Energy Technology Data Exchange (ETDEWEB)

Lin, Wen-Shan [Chung Shan Institute of Science and Technology, P.O. Box 90008-15-3, Lung-Tan, Tao-Yuan, 32526 Taiwan (China)

2005-12-01

Discovered is a quasi-steady ablation phenomenon on the surface of a two-layer composite which is formed by a layer of ablative material and another layer of non-ablative substrate. Theoretical exact solutions of quasi-steady ablation rate, the associated temperature distribution and end-of-ablation time of this two-layer composite are derived. A criterion for the occurrence of quasi-steady ablation is presented also. A one-dimensional transient numerical model is developed to perform a number of numerical experiments and hence to verify the correctness of the above theoretical solutions for the current quasi-steady ablation phenomenon. Based on the current results, a new method of measuring the ablation (or sublimation) heat is also proposed. (author)

Moored surface buoy observations of the diurnal warm layer

KAUST Repository

Prytherch, J.

2013-09-01

An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5-15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models. ©2013. American Geophysical Union. All Rights Reserved.

Moored surface buoy observations of the diurnal warm layer

KAUST Repository

Prytherch, J.; Farrar, J. T.; Weller, R. A.

2013-01-01

An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5-15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models. ©2013. American Geophysical Union. All Rights Reserved.

Junction Quality of SnO2-Based Perovskite Solar Cells Investigated by Nanometer-Scale Electrical Potential Profiling.

Science.gov (United States)

Xiao, Chuanxiao; Wang, Changlei; Ke, Weijun; Gorman, Brian P; Ye, Jichun; Jiang, Chun-Sheng; Yan, Yanfa; Al-Jassim, Mowafak M

2017-11-08

Electron-selective layers (ESLs) and hole-selective layers (HSLs) are critical in high-efficiency organic-inorganic lead halide perovskite (PS) solar cells for charge-carrier transport, separation, and collection. We developed a procedure to assess the quality of the ESL/PS junction by measuring potential distribution on the cross section of SnO 2 -based PS solar cells using Kelvin probe force microscopy. Using the potential profiling, we compared three types of cells made of different ESLs but otherwise having an identical device structure: (1) cells with PS deposited directly on bare fluorine-doped SnO 2 (FTO)-coated glass; (2) cells with an intrinsic SnO 2 thin layer on the top of FTO as an effective ESL; and (3) cells with the SnO 2 ESL and adding a self-assembled monolayer (SAM) of fullerene. The results reveal two major potential drops or electric fields at the ESL/PS and PS/HSL interfaces. The electric-field ratio between the ESL/PS and PS/HSL interfaces increased in devices as follows: FTO ESL ESL cells may result from the reduction in voltage loss at the PS/HSL back interface and the improvement of V oc from the prevention of hole recombination at the ESL/PS front interface. The further improvements with adding an SAM is caused by the defect passivation at the ESL/PS interface, and hence, improvement of the junction quality. These nanoelectrical findings suggest possibilities for improving the device performance by further optimizing the SnO 2 -based ESL material quality and the ESL/PS interface.

Investigation of Selective Laser Melting Surface Alloyed Aluminium Metal Matrix Dispersive Reinforced Layers

Science.gov (United States)

Kamburov, V. V.; Dimitrova, R. B.; Kandeva, M. K.; Sofronov, Y. P.

2018-01-01

The aim of the paper is to investigate the improvement of mechanical properties and in particular wear resistance of laser surface alloyed dispersive reinforced thin layers produced by selective laser melting (SLM) technology. The wear resistance investigation of aluminium matrix composite layers in the conditions of dry friction surface with abrasive particles and nanoindentation tests were carried out. The process parameters (as scan speed) and their impact on the wear resistant layers have been evaluated. The alloyed layers containing metalized SiC particles were studied by Optical and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray microanalysis (EDX). The obtained experimental results of the laser alloyed thin layers show significant development of their wear resistance and nanohardness due to the incorporated reinforced phase of electroless nickel coated SiC particles.

Native SrTiO3 (001) surface layer from resonant Ti L2,3 reflectance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Valvidares, Manuel; Huijben, Mark; Yu, Pu; Ramesh, Ramamoorthy; Kortright, Jeffrey

2010-11-03

We quantitatively model resonant Ti L2,3 reflectivity Rs,p(q, hn) from several SrTiO3 (001) single crystals having different initial surface preparations and stored in ambient conditions before and between measurements. All samples exhibit unexpected 300 K Rs(hn) - Rp(hn) anisotropy corresponding to weak linear dichroism and tetragonal distortion of the TiO6 octahedra indicating a surface layer with properties different from cubic SrTiO3. Oscillations in Rs(q) confirm a ubiquitous surface layer 2-3 nm thick that evolves over a range of time scales. Resonant optical constant spectra derived from Rs,p(hn) assuming a uniform sample are refined using a single surface layer to fit measured Rs(q). Differences in surface layer and bulk optical properties indicate that the surface is significantly depleted in Sr and enriched in Ti and O. While consistent with the tendency of SrTiO3 surfaces toward non-stoichiometry, this layer does not conform simply to existing models for the near surface region and apparently forms via room temperature surface reactions with the ambient. This new quantitative spectral modeling approach is generally applicable and has potential to study near-surface properties of a variety of systems with unique chemical and electronic sensitivities.

University ESL Teachers' Socialization in School Workplace toward Teaching Culturally Diverse Students

Science.gov (United States)

Huang, Hsiang-Ling

2011-01-01

Employing interpretive theory, this study investigated 331 university ESL teachers' socialization in language programs for international students. Looking beyond teacher preparatory education, in-service teachers' workplace experiences are essential to study because experience is instrumental in the shaping of belief systems (Wu and Shaffer,…

Challenging Inquiry and Building Community: Analyzing ESL and Bilingual Teachers' Narratives

Science.gov (United States)

Musanti, Sandra I.

2017-01-01

The study explores English as a second language (ESL) and bilingual teachers' narratives within a learning community as they collectively engage in reflecting on practices to more effectively support English learners. This longitudinal qualitative study integrates narrative inquiry approach and critical incident methodology. Participants were…

Analyzing surface features on icy satellites using a new two-layer analogue model

Science.gov (United States)

Morales, K. M.; Leonard, E. J.; Pappalardo, R. T.; Yin, A.

2017-12-01

The appearance of similar surface morphologies across many icy satellites suggests potentially unified formation mechanisms. Constraining the processes that shape the surfaces of these icy worlds is fundamental to understanding their rheology and thermal evolution—factors that have implications for potential habitability. Analogue models have proven useful for investigating and quantifying surface structure formation on Earth, but have only been sparsely applied to icy bodies. In this study, we employ an innovative two-layer analogue model that simulates a warm, ductile ice layer overlain by brittle surface ice on satellites such as Europa and Enceladus. The top, brittle layer is composed of fine-grained sand while the ductile, lower viscosity layer is made of putty. These materials were chosen because they scale up reasonably to the conditions on Europa and Enceladus. Using this analogue model, we investigate the role of the ductile layer in forming contractional structures (e.g. folds) that would compensate for the over-abundance of extensional features observed on icy satellites. We do this by simulating different compressional scenarios in the analogue model and analyzing whether the resulting features resemble those on icy bodies. If the resulting structures are similar, then the model can be used to quantify the deformation by calculating strain. These values can then be scaled up to Europa or Enceladus and used to quantity the observed surface morphologies and the amount of extensional strain accommodated by certain features. This presentation will focus on the resulting surface morphologies and the calculated strain values from several analogue experiments. The methods and findings from this work can then be expanded and used to study other icy bodies, such as Triton, Miranda, Ariel, and Pluto.

The Challenges of Using the Communicative Approach (CA) in the Teaching of English as a Second Language (ESL) in Zimbabwe: Implications for ESL Teacher Education

Science.gov (United States)

Mutekwa, Anias

2013-01-01

This article examines studies done on the use of the CA locally, in addition to insights from studies done abroad, as well as critically examining the nature of the CA and the language situation in Zimbabwe, to identify and discuss the main challenges associated with the use of this approach to the teaching of ESL in Zimbabwe and its implications…

CWEX: Crop/wind-energy experiment: Observations of surface-layer, boundary-layer and mesoscale interactions with a wind farm

Science.gov (United States)

Large wind turbines perturb mean and turbulent wind characteristics, which modify fluxes between the vegetated surface and the lower boundary layer. While simulations have suggested that wind farms could create significant changes in surface fluxes of heat, momentum, moisture, and CO2 over hundreds ...

Crop/Wind-energy Experiment (CWEX): Observations of surface-layer, boundary-layer and mesoscale interactions with a wind farm

Science.gov (United States)

Perturbations of mean and turbulent wind characteristics by large wind turbines modify fluxes between the vegetated surface and the lower boundary layer. While simulations have suggested that wind farms could significantly change surface fluxes of heat, momentum, moisture, and CO2 over hundreds of s...

Surface analysis of uranyl fluoride layers with a glow discharge lamp

International Nuclear Information System (INIS)

Nel, J.T.; Stander, C.M.; Boehmer, R.G.

1991-01-01

Surface analysis with a Grimm-type glow discharge lamp was used to analyse uranyl fluoride layers that had formed on a nickel substrate after exposure to UF 6 . Narrow-band optical filters were used to isolate the intensities of three fluorine emission lines. An in-depth profile of layer composition was obtained. (author)

Oral Communication in ESL Through Improvisations, Playwriting And Rehearsals

Directory of Open Access Journals (Sweden)

Chamkaur Gill

2013-01-01

Full Text Available The application of drama strategies which focus more on meaning than on form can provide an impetus for ESL learners to be more confident about speaking, thereby increasing the quantity of their spoken English. This paper discusses existing research and the author’s own experiences in an attempt to highlight the positive effects of improvisations, playwriting and rehearsals on the oral output of learners in relation to communicative English.

Metal Surface Modification for Obtaining Nano- and Sub-Nanostructured Protective Layers

Science.gov (United States)

Ledovskykh, Volodymyr; Vyshnevska, Yuliya; Brazhnyk, Igor; Levchenko, Sergiy

2017-03-01

Regularities of the phase protective layer formation in multicomponent systems involving inhibitors with different mechanism of protective action have been investigated. It was shown that optimization of the composition of the inhibition mixture allows to obtain higher protective efficiency owing to improved microstructure of the phase layer. It was found that mechanism of the film formation in the presence of NaNO2-PHMG is due to deposition of slightly soluble PHMG-Fe complexes on the metal surface. On the basis of the proposed mechanism, the advanced surface engineering methods for obtaining nanoscaled and sub-nanostructured functional coatings may be developed.

Investigation of surface layer on rolled recycled AA5050 in relation to Filiform Corrosion

NARCIS (Netherlands)

2007-01-01

The presence of a heavily deformed surface layer (a few microns thick) on rolled aluminium alloy is understood to be one of the main reasons contributing to the Filiform Corrosion (FFC) susceptibility of the alloy. The surface layer is formed during the thermo-mechanical processing of the sheet

Seasonal features of atmospheric surface-layer characteristics over a tropical coastal station in Southern India

International Nuclear Information System (INIS)

Hari Prasad, K.B.R.R.; Srinivas, C.V.; Baskaran, R.; Venkatraman, B.

2016-01-01

Dispersion of air-borne effluents occurs in the atmospheric boundary layer (ABL) where turbulence is the main physical processes. In the surface layer of ABL, the mechanical (shear) generation of turbulence exceeds the buoyant generation or consumption of turbulence. In this layer, under steady state and horizontally homogeneous conditions various forces in the governing equation can be neglected and one can apply Monin-Obukhov Similarity Theory (MOST) to estimate the turbulent fluxes and other surface layer variables. Understanding the turbulent characteristics of the surface layer is vital for modeling of turbulent diffusion in regional numerical weather and pollution dispersion models. The objective of this study is to verify the validity of the MOST at the coastal site Kalpakkam under various atmospheric stability conditions with respect to different seasons for modeling atmospheric dispersion of radioactive effluents

Effect of inversion layer at iron pyrite surface on photovoltaic device

Science.gov (United States)

Uchiyama, Shunsuke; Ishikawa, Yasuaki; Uraoka, Yukiharu

2018-03-01

Iron pyrite has great potential as a thin-film solar cell material because it has high optical absorption, low cost, and is earth-abundant. However, previously reported iron pyrite solar cells showed poor photovoltaic characteristics. Here, we have numerically simulated its photovoltaic characteristics and band structures by utilizing a two-dimensional (2D) device simulator, ATLAS, to evaluate the effects of an inversion layer at the surface and a high density of deep donor defect states in the bulk. We found that previous device structures did not consider the inversion layer at the surface region of iron pyrite, which made it difficult to obtain the conversion efficiency. Therefore, we remodeled the device structure and suggested that removing the inversion layer and reducing the density of deep donor defect states would lead to a high conversion efficiency of iron pyrite solar cells.

Surface layer conditions of the atmosphere over western Bay of Bengal during Monex

Digital Repository Service at National Institute of Oceanography (India)

Anto, A.F.; Rao, L.V.G.; Somayajulu, Y.K.

Based on surface meteorological data and wave data collected from 2 stations in the western Bay of Bengal in July 1979, surface layer (SL) conditions of the atmosphere for different situations of surface circulations and the associated sea surface...

Changes of electrical conductivity of the metal surface layer by the laser alloying with foreign elements

Science.gov (United States)

Kostrubiec, Franciszek; Pawlak, Ryszard; Raczynski, Tomasz; Walczak, Maria

1994-09-01

Laser treatment of the surface of materials is of major importance for many fields technology. One of the latest and most significant methods of this treatment is laser alloying consisting of introducing foreign atoms into the metal surface layer during the reaction of laser radiation with the surface. This opens up vast possibilities for the modification of properties of such a layer (obtaining layers of increased microhardness, increased resistance to electroerosion in an electric arc, etc.). Conductivity of the material is a very important parameter in case of conductive materials used for electrical contacts. The paper presents the results of studies on change in electrical conductivity of the surface layer of metals alloyed with a laser. A comparative analysis of conductivity of base metal surface layers prior to and following laser treatment has been performed. Depending on the base metal and the alloying element, optical treatment parameters allowing a required change in the surface layer conductivity have been selected. A very important property of the contact material is its resistance to plastic strain. It affects the real value of contact surface coming into contact and, along with the material conductivity, determines contact resistance and the amount of heat generated in place of contact. These quantities are directly related to the initiation and the course of an arc discharge, hence they also affect resistance to electroerosion. The parameter that reflects plastic properties with loads concentrated on a small surface, as is the case with a reciprocal contact force of two real surfaces with their irregularities being in contact, is microhardness. In the paper, the results of investigations into microhardness of modified surface layers compared with base metal microhardness have been presented.

An Optimal Estimation Method to Obtain Surface Layer Turbulent Fluxes from Profile Measurements

Science.gov (United States)

Kang, D.

2015-12-01

In the absence of direct turbulence measurements, the turbulence characteristics of the atmospheric surface layer are often derived from measurements of the surface layer mean properties based on Monin-Obukhov Similarity Theory (MOST). This approach requires two levels of the ensemble mean wind, temperature, and water vapor, from which the fluxes of momentum, sensible heat, and water vapor can be obtained. When only one measurement level is available, the roughness heights and the assumed properties of the corresponding variables at the respective roughness heights are used. In practice, the temporal mean with large number of samples are used in place of the ensemble mean. However, in many situations the samples of data are taken from multiple levels. It is thus desirable to derive the boundary layer flux properties using all measurements. In this study, we used an optimal estimation approach to derive surface layer properties based on all available measurements. This approach assumes that the samples are taken from a population whose ensemble mean profile follows the MOST. An optimized estimate is obtained when the results yield a minimum cost function defined as a weighted summation of all error variance at each sample altitude. The weights are based one sample data variance and the altitude of the measurements. This method was applied to measurements in the marine atmospheric surface layer from a small boat using radiosonde on a tethered balloon where temperature and relative humidity profiles in the lowest 50 m were made repeatedly in about 30 minutes. We will present the resultant fluxes and the derived MOST mean profiles using different sets of measurements. The advantage of this method over the 'traditional' methods will be illustrated. Some limitations of this optimization method will also be discussed. Its application to quantify the effects of marine surface layer environment on radar and communication signal propagation will be shown as well.

Implementation of Multiple Intelligences Supported Project-Based Learning in EFL/ESL Classrooms

Science.gov (United States)

Bas, Gokhan

2008-01-01

This article deals with the implementation of Multiple Intelligences supported Project-Based learning in EFL/ESL Classrooms. In this study, after Multiple Intelligences supported Project-based learning was presented shortly, the implementation of this learning method into English classrooms. Implementation process of MI supported Project-based…

Instructional Practices in Teaching Literature: Observations of ESL Classrooms in Malaysia

Science.gov (United States)

Sidhu, Gurnam Kaur; Fook, Chan Yuen; Kaur, Sarjit

2010-01-01

Literature is an expression of life through the medium of language and in the ESL classroom it is often seen as an authentic means of learning the target language. A literature-enriched curriculum not only helps learners improve their reading and writing skills but more importantly helps them internalise grammar and vocabulary. The many benefits…

The Interaction of Theory, Philosophy, and Practice in ESL Writing Conferences

Science.gov (United States)

Eckstein, Grant

2013-01-01

TESOL theory is intended to inform teacher practice, but studying what teachers actually do in a given teaching context can sometimes lead to better theory. This report illustrates an area in which practice informed theory in the context of 1-on-1 writing conferences for prematriculated ESL writers. This report describes the creation and…

Using Electronic Readers: Action Research in an Intermediate Adult ESL Class

Science.gov (United States)

Fraser, Monica; Abbott, Marilyn

2016-01-01

The use of portable electronic reading devices in the English as a second language (ESL) classroom has the potential to positively impact learners' reading engagement and language skill development. However, due to the lack of research, few guidelines are available to inform instructors of the benefits and challenges of using these devices in ESL…

Postgraduate Diploma Collaborative Assignment: Implications for ESL Students and Curriculum Design

Science.gov (United States)

Grant, T.

2008-01-01

The commerce faculty at the University of Cape Town (UCT) offers a 1-year, postgraduate management diploma that is regarded as a mini-MBA. It appeals to a wide variety of mainly English-as-second language (ESL) students. In the past, core course diploma lecturers in marketing, tourism and leisure, enterprise management and sport management…

Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength.

Science.gov (United States)

Bijelic-Donova, Jasmina; Garoushi, Sufyan; Lassila, Lippo V J; Vallittu, Pekka K

2015-02-01

An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short-fiber-reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated. Four different restorative composites were selected: everX Posterior (a short-fiber-reinforced composite), Z250, SupremeXT, and Silorane. All composites were evaluated regarding the thickness of the oxygen inhibition layer and for shear bond strength. An equal amount of each composite was polymerized in air between two glass plates and the thickness of the oxygen inhibition layer was measured using a stereomicroscope. Cylindrical-shaped specimens were prepared for measurement of shear bond strength by placing incrementally two layers of the same composite material. Before applying the second composite layer, the first increment's bonding site was treated as follows: grinding with 1,000-grit silicon-carbide (SiC) abrasive paper, or treatment with ethanol or with water-spray. The inhibition depth was lowest (11.6 μm) for water-sprayed Silorane and greatest (22.9 μm) for the water-sprayed short-fiber-reinforced composite. The shear bond strength ranged from 5.8 MPa (ground Silorane) to 36.4 MPa (water-sprayed SupremeXT). The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short-fiber-reinforced composite. Thus, more durable adhesion with short-fiber-reinforced composite is expected. © 2014 Eur J Oral Sci.

Layer Dependence of Graphene for Oxidation Resistance of Cu Surface

Institute of Scientific and Technical Information of China (English)

Yu-qing Song; Xiao-ping Wang

2017-01-01

We studied the oxidation resistance of graphene-coated Cu surface and its layer dependence by directly growing monolayer graphene with different multilayer structures coexisted,diminishing the influence induced by residue and transfer technology.It is found that the Cu surface coated with the monolayer graphene demonstrate tremendous difference in oxidation pattern and oxidation rate,compared to that coated with the bilayer graphene,which is considered to be originated from the strain-induced linear oxidation channel in monolayer graphene and the intersection of easily-oxidized directions in each layer of bilayer graphene,respectively.We reveal that the defects on the graphene basal plane but not the boundaries are the main oxidation channel for Cu surface under graphene protection.Our finding indicates that compared to putting forth efforts to improve the quality of monolayer graphene by reducing defects,depositing multilayer graphene directly on metal is a simple and effective way to enhance the oxidation resistance of graphene-coated metals.

Deposition of thin layer (monoatomic layer) of barium on gold single crystal surfaces and studies of its oxidation employing X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Ahmad, H.; Ahmad, R.; Khalid, M.; Alvi, R.A.

2007-01-01

Due to the high reactivity of barium with oxygen, some oxygen diffuse into the bulk to form bulk oxide and it is very difficult to differentiate the oxide over layer and the bulk oxide. To study the oxidation of barium surface layer, a thin layer (monolayer) of barium is developed over gold single crystal surface. Gold is selected as support because it is one of the least reactive metal in transition metal group and have very low probability of reaction with oxygen at room temperature (300K). Nitrous oxide (N/sub 2/O) was used as oxidant. Thin layer of barium was deposited on Au(100) surface. The barium coverage on gold surface was calculated that varied from 0.4 to 1.4 monolayer (ML). Photoelectron spectra for O(ls), N(ls), Ba (3d), and Au (4f) have been recorded on X-ray photoelectron spectrometer at different binding energy region specific for each element. The decomposition of nitrous oxide has been observed in all cases. It has found that nitrogen is evolved in the gaseous state and oxygen is adsorbed/chemisorbed on barium over layer. (author)

Influence of substrate preparation on the shaping of the topography of the surface of nanoceramic oxide layers

Science.gov (United States)

Bara, Marek; Kubica, Marek

2014-02-01

The paper discusses the shaping mechanism and changes occurring in the structure and topography of the surface of nanoceramic oxide layers during their formation. The paper presents the influence of substrate preparation on the surface topography of oxide layers. The layers were produced via hard anodizing on the EN AW-5251 aluminum alloy. The layers obtained were subjected to microscope examinations, image and chemical composition analyses, and stereometric examinations. Heredity of substrate properties in the topography of the surface of nanoceramic oxide layers formed as a result of electrochemical oxidation has been shown.

Research Note : Near-surface layer replacement for sparse data: Is interpolation needed?

NARCIS (Netherlands)

Sun, Yimin; Verschuur, D.J.; Luo, Yi

2017-01-01

Near-surface problem is a common challenge faced by land seismic data processing, where often, due to near-surface anomalies, events of interest are obscured. One method to handle this challenge is near-surface layer replacement, which is a wavefield reconstruction process based on downward

Absorption and reflectivity of the lithium niobate surface masked with a graphene layer

Directory of Open Access Journals (Sweden)

O. Salas

2017-01-01

Full Text Available We performed simulations of the interaction of a graphene layer with the surface of lithium niobate utilizing density functional theory and molecular dynamics at 300K and atmospheric pressure. We found that the graphene layer is physisorbed on the lithium niobate surface with an adsorption energy of -0.8205 eV/(carbon-atom. Subsequently, the energy band structure, the optical absorption and reflectivity of the new system were calculated. We found important changes in these physical properties with respect to the corresponding ones of a graphene layer and of a lithium niobate crystal.

Are atmospheric surface layer flows ergodic?

Science.gov (United States)

Higgins, Chad W.; Katul, Gabriel G.; Froidevaux, Martin; Simeonov, Valentin; Parlange, Marc B.

2013-06-01

The transposition of atmospheric turbulence statistics from the time domain, as conventionally sampled in field experiments, is explained by the so-called ergodic hypothesis. In micrometeorology, this hypothesis assumes that the time average of a measured flow variable represents an ensemble of independent realizations from similar meteorological states and boundary conditions. That is, the averaging duration must be sufficiently long to include a large number of independent realizations of the sampled flow variable so as to represent the ensemble. While the validity of the ergodic hypothesis for turbulence has been confirmed in laboratory experiments, and numerical simulations for idealized conditions, evidence for its validity in the atmospheric surface layer (ASL), especially for nonideal conditions, continues to defy experimental efforts. There is some urgency to make progress on this problem given the proliferation of tall tower scalar concentration networks aimed at constraining climate models yet are impacted by nonideal conditions at the land surface. Recent advancements in water vapor concentration lidar measurements that simultaneously sample spatial and temporal series in the ASL are used to investigate the validity of the ergodic hypothesis for the first time. It is shown that ergodicity is valid in a strict sense above uniform surfaces away from abrupt surface transitions. Surprisingly, ergodicity may be used to infer the ensemble concentration statistics of a composite grass-lake system using only water vapor concentration measurements collected above the sharp transition delineating the lake from the grass surface.

Hard Surface Layers by Pack Boriding and Gaseous Thermo-Reactive Deposition and Diffusion Treatments

DEFF Research Database (Denmark)

Christiansen, Thomas Lundin; Bottoli, Federico; Dahl, Kristian Vinter

2017-01-01

) layers with hardnesses up to 1800 HV. Titanizing of ARNE tool steel results in a surface layer consisting of TiC with a hardness of approximately 4000 HV. Duplex treatments, where boriding is combined with subsequent (TRD) titanizing, result in formation of hard TiB2 on top of a thick layer of Fe......Thermo-reactive deposition and diffusion (TRD) and boriding are thermochemical processes that result in very high surface hardness by conversion of the surface into carbides/nitrides and borides, respectively. These treatments offer significant advantages in terms of hardness, adhesion, tribo...... subjected to TRD (chromizing and titanizing) and boriding treatments. For the steels with low carbon content, chromizing results in surface alloying with chromium, i.e., formation of a (soft) “stainless” surface zone. Steels containing higher levels of carbon form chromium carbide (viz. Cr23C6, Cr7C3...

Experimental Investigation of Surface Layer Properties of High Thermal Conductivity Tool Steel after Electrical Discharge Machining

Directory of Open Access Journals (Sweden)

Rafał Świercz

2017-12-01

Full Text Available New materials require the use of advanced technology in manufacturing complex shape parts. One of the modern materials widely used in the tool industry for injection molds or hot stamping dies is high conductivity tool steel (HTCS 150. Due to its hardness (55 HRC and thermal conductivity at 66 W/mK, this material is difficult to machine by conventional treatment and is being increasingly manufactured by nonconventional technology such as electrical discharge machining (EDM. In the EDM process, material is removed from the workpiece by a series of electrical discharges that cause changes to the surface layers properties. The final state of the surface layer directly influences the durability of the produced elements. This paper presents the influence of EDM process parameters: discharge current Ic and the pulse time ton on surface layer properties. The experimental investigation was carried out with an experimental methodology design. Surface layers properties including roughness 3D parameters, the thickness of the white layer, heat affected zone, tempered layer and occurring micro cracks were investigated and described. The influence of the response surface methodology (RSM of discharge current Ic and the pulse time ton on the thickness of the white layer and roughness parameters Sa, Sds and Ssc were described and established.

Heat transfer control in a plane magnetic fluid layer with a free surface

International Nuclear Information System (INIS)

Bashtovoi, V.G.; Pogirnitskaya, S.G.; Reks, A.G.

1993-01-01

The heat transfer mechanisms that are specific to a magnetic liquid have been already investigated extensively. The high sensitivity of the free magnetic liquid surface to the external magnetic field introduces a new feature into the heat transfer process. In the present work, the authors have investigated the possibility of controlling the heat transfer through the phenomenon of magnetic liquid surface instability in a uniform magnetic field. The conditions for heat transfer through a chamber, partially filled with a magnetic liquid, are governed by the characteristics of the free liquid surface and by its stability and development in the supercritical magnetic fields. The authors consider a model two-dimensional problem of heat transfer through a two-layer medium consisting of horizontally situated immiscible layers of magnetic and nonmagnetic liquids with given thermal conductivities. In the absence of an external magnetic field, the interface of the liquids represents a plane surface. In fields which exceed the critical magnitude, the interface is deformed along the wave. As the field intensity is increased, the amplitude of interface distortion becomes larger. The two-dimensional shape of the free magnetic liquid surface may be realized experimentally using two plane layers of magnetic and nonmagnetic liquids in a uniform magnetic field tangent to the interface of the component layers. 7 refs., 9 figs

Improving clinical communication of students with English as a second language (ESL) using online technology: a small scale evaluation study.

Science.gov (United States)

Rogan, Fran; San Miguel, Caroline

2013-09-01

Increasingly, students with English as a second language (ESL) are enrolled in nursing degrees in English speaking countries (Wang et al., 2008). However, they may be at risk of clinical practice failure due to communication difficulties associated with unfamiliar linguistic and cultural factors (Guhde, 2003). This paper describes and evaluates an innovation to assist ESL nursing students at an Australian university develop their clinical communication skills and practice readiness by providing online learning resources, using podcast and vodcast technology, that blend with classroom activities and facilitate flexible and independent learning. The innovation builds on an intensive clinical language workshop program called 'Clinically Speaking' which has evolved through a cyclical process of ongoing research to produce resources in response to students' learning needs. Whilst uptake of the resources was modest, students of ESL as well as English speaking backgrounds (ESB) found the resources improved their clinical preparation and confidence by increasing their understanding of expectations, clinical language and communication skills. The innovation, developed with a modest budget, shows potential in developing ESL and ESB students' readiness for clinical communication, enabling them to engage in clinical practice to develop competency standards required of nursing graduates and registration authorities. Copyright © 2012 Elsevier Ltd. All rights reserved.

Healthy eating for life: rationale and development of an English as a second language (ESL) curriculum for promoting healthy nutrition.

Science.gov (United States)

Martinez, Josefa L; Rivers, Susan E; Duncan, Lindsay R; Bertoli, Michelle; Domingo, Samantha; Latimer-Cheung, Amy E; Salovey, Peter

2013-12-01

Low health literacy contributes significantly to cancer health disparities disadvantaging minorities and the medically underserved. Immigrants to the United States constitute a particularly vulnerable subgroup of the medically underserved, and because many are non-native English speakers, they are pre-disposed to encounter language and literacy barriers across the cancer continuum. Healthy Eating for Life (HE4L) is an English as a second language (ESL) curriculum designed to teach English language and health literacy while promoting fruit and vegetable consumption for cancer prevention. This article describes the rationale, design, and content of HE4L. HE4L is a content-based adult ESL curriculum grounded in the health action process approach to behavior change. The curriculum package includes a soap opera-like storyline, an interactive student workbook, a teacher's manual, and audio files. HE4L is the first teacher-administered, multimedia nutrition-education curriculum designed to reduce cancer risk among beginning-level ESL students. HE4L is unique because it combines adult ESL principles, health education content, and behavioral theory. HE4L provides a case study of how evidence-based, health promotion practices can be implemented into real-life settings and serves as a timely, useful, and accessible nutrition-education resource for health educators.

Evaluating Pragmatic Competence in Nigerian Undergraduates' Language Errors within Descriptive ESL Writing

Science.gov (United States)

Muhammad, Anas Sa'idu; Nair, Subadrah Madhawa

2017-01-01

This study investigates the level of pragmatic competence for ESL writing skills among Nigerian undergraduates. Methodologically, it adopts descriptive research design within the explanatory framework of the QUAN-Qual model. The instruments used are descriptive essay text and focus group interview questions. In writing the descriptive essays, a…

Teaching and Evaluation of Critical Appraisal Skills to Postgraduate ESL Engineering Students

Science.gov (United States)

Melles, Gavin

2009-01-01

Enrolments in postgraduate engineering in Australia include a significant proportion of Asian ESL (English as a Second Language) students, and there is some debate in the literature about whether they are capable of critical appraisal. Content-based discipline-specific EAP (English for Academic Purposes) courses provide an environment for…

Boundary layer transition observations on a body of revolution with surface heating and cooling in water

Science.gov (United States)

Arakeri, V. H.

1980-04-01

Boundary layer flow visualization in water with surface heat transfer was carried out on a body of revolution which had the predicted possibility of laminar separation under isothermal conditions. Flow visualization was by in-line holographic technique. Boundary layer stabilization, including elimination of laminar separation, was observed to take place on surface heating. Conversely, boundary layer destabilization was observed on surface cooling. These findings are consistent with the theoretical predictions of Wazzan et al. (1970).

Functionalised nanoscale coatings using layer-by-layer assembly for imparting antibacterial properties to polylactide-co-glycolide surfaces.

Science.gov (United States)

Gentile, Piergiorgio; Frongia, Maria E; Cardellach, Mar; Miller, Cheryl A; Stafford, Graham P; Leggett, Graham J; Hatton, Paul V

2015-07-01

In order to achieve high local biological activity and reduce the risk of side effects of antibiotics in the treatment of periodontal and bone infections, a localised and temporally controlled delivery system is desirable. The aim of this research was to develop a functionalised and resorbable surface to contact soft tissues to improve the antibacterial behaviour during the first week after its implantation in the treatment of periodontal and bone infections. Solvent-cast poly(d,l-lactide-co-glycolide acid) (PLGA) films were aminolysed and then modified by Layer-by-Layer technique to obtain a nano-layered coating using poly(sodium4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) as polyelectrolytes. The water-soluble antibiotic, metronidazole (MET), was incorporated from the ninth layer. Infrared spectroscopy showed that the PSS and PAH absorption bands increased with the layer number. The contact angle values had a regular alternate behaviour from the ninth layer. X-ray Photoelectron Spectroscopy evidenced two distinct peaks, N1s and S2p, indicating PAH and PSS had been introduced. Atomic Force Microscopy showed the presence of polyelectrolytes on the surface with a measured roughness about 10nm after 20 layers' deposition. The drug release was monitored by Ultraviolet-visible spectroscopy showing 80% loaded-drug delivery in 14 days. Finally, the biocompatibility was evaluated in vitro with L929 mouse fibroblasts and the antibacterial properties were demonstrated successfully against the keystone periodontal bacteria Porphyromonas gingivalis, which has an influence on implant failure, without compromising in vitro biocompatibility. In this study, PLGA was successfully modified to obtain a localised and temporally controlled drug delivery system, demonstrating the potential value of LbL as a coating technology for the manufacture of medical devices with advanced functional properties. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd

Making the Invisible Visible: A Responsive Evaluation Study of ESL and Spanish Language Services for Immigrants in a Small Rural County in Indiana

Science.gov (United States)

Pawan, Faridah; Thomalla, Therese Groff

2005-01-01

This article describes a responsive evaluation study of ESL services and Spanish language services for immigrants in a rural county in Indiana. An ESL specialist led the evaluation of language services in the county from the perspectives of language providers and recipients. The responsive evaluation--a form of action research that uses…

Influence of carbon monoxide to the surface layer of uranium metal and its oxides

International Nuclear Information System (INIS)

Wang Xiaoling; Fu Yibei; Xie Renshou; Huang Ruiliang

1996-09-01

The surface structures of uranium metal and triuranium octaoxide (U 3 O 8 ) and the influence of carbon monoxide to the surface layers have been studied by X-ray photoelectron spectroscopy (XPS). After exposure to carbon monoxide, contents of oxygen in the surface oxides of uranium metal and U 3 O 8 are decreased and O/U ratios decrease 7.2%, 8.0% respectively. The investigation indicated the surface layers of uranium metal and its oxides were forbidden to further oxidation in the atmosphere of carbon monoxide. (11 refs., 9 figs., 2 tabs.)

Microstructures of tribologically modified surface layers in two-phase alloys

International Nuclear Information System (INIS)

Figueroa, C G; Ortega, I; Jacobo, V H; Ortiz, A; Bravo, A E; Schouwenaars, R

2014-01-01

When ductile alloys are subject to sliding wear, small increments of plastic strain accumulate into severe plastic deformation and mechanical alloying of the surface layer. The authors constructed a simple coaxial tribometer, which was used to study this phenomenon in wrought Al-Sn and cast Cu-Mg-Sn alloys. The first class of materials is ductile and consists of two immiscible phases. Tribological modification is observed in the form of a transition zone from virgin material to severely deformed grains. At the surface, mechanical mixing of both phases competes with diffusional unmixing. Vortex flow patterns are typically observed. The experimental Cu-Mg-Sn alloys are ductile for Mg-contents up to 2 wt% and consist of a- dendrites with a eutectic consisting of a brittle Cu 2 Mg-matrix with α-particles. In these, the observations are similar to the Al-Sn Alloys. Alloys with 5 wt% Mg are brittle due to the contiguity of the eutectic compound. Nonetheless, under sliding contact, this compound behaves in a ductile manner, showing mechanical mixing of a and Cu 2 Mg in the top layers and a remarkable transition from a eutectic to cellular microstructure just below, due to severe shear deformation. AFM-observations allow identifying the mechanically homogenized surface layers as a nanocrystalline material with a cell structure associated to the sliding direction

Make your point! debate for ESL/EFL students

CERN Document Server

Lubetsky, Michael H

2014-01-01

This valuable workbook and downloadable audio can turn any ESL student into an accomplished debater!Make Your Point! opens the world of formal debate to the English learner. Debate fundamentals are taught form the first chapter in a student-centered format suitable for large and small classes alike.Each of the ten chapters offers a ""language focus"" and a ""debatable focus."" As students learn new debate skills, they also build important language skills. All task chains integrate speaking, listening, reading and writing activities. Most activities are intended for pairs and small groups.

Surface photovoltage studies of p-type AlGaN layers after reactive-ion etching

Science.gov (United States)

McNamara, J. D.; Phumisithikul, K. L.; Baski, A. A.; Marini, J.; Shahedipour-Sandvik, F.; Das, S.; Reshchikov, M. A.

2016-10-01

The surface photovoltage (SPV) technique was used to study the surface and electrical properties of Mg-doped, p-type AlxGa1-xN (0.06 GaN:Mg thin films and from the predictions of a thermionic model for the SPV behavior. In particular, the SPV of the p-AlGaN:Mg layers exhibited slower-than-expected transients under ultraviolet illumination and delayed restoration to the initial dark value. The slow transients and delayed restorations can be attributed to a defective surface region which interferes with normal thermionic processes. The top 45 nm of the p-AlGaN:Mg layer was etched using a reactive-ion etch which caused the SPV behavior to be substantially different. From this study, it can be concluded that a defective, near-surface region is inhibiting the change in positive surface charge by allowing tunneling or hopping conductivity of holes from the bulk to the surface, or by the trapping of electrons traveling to the surface by a high concentration of defects in the near-surface region. Etching removes the defective layer and reveals a region of presumably higher quality, as evidenced by substantial changes in the SPV behavior.

Passing the English as a second language (ESL) supplemental texes exam keys to certification and language proficient learners

CERN Document Server

Wilmore, Elaine L

2014-01-01

Master the TExES with down-to-earth test prep strategies ESL certification is attainable if one understands the domains and competencies represented in the test and masters test prep skills. Dr. Elaine Wilmore, known for her popular TExES preparation seminars, synthesizes her knowledge and experiences and gives readers a practical approach to passing the ESL Supplemental Exam. Written in a conversational tone, the book uses real examples to help readers connect theory with actual practice and offers: Thorough discussions of relevant concepts related to domains and competencies Tables and graph

The use of artificial intelligence methods for visual analysis of properties of surface layers

Directory of Open Access Journals (Sweden)

Tomasz Wójcicki

2014-12-01

Full Text Available [b]Abstract[/b]. The article presents a selected area of research on the possibility of automatic prediction of material properties based on the analysis of digital images. Original, holistic model of forecasting properties of surface layers based on a multi-step process that includes the selected methods of processing and analysis of images, inference with the use of a priori knowledge bases and multi-valued fuzzy logic, and simulation with the use of finite element methods is presented. Surface layers characteristics and core technologies of their production processes such as mechanical, thermal, thermo-mechanical, thermo-chemical, electrochemical, physical are discussed. Developed methods used in the model for the classification of images of the surface layers are shown. The objectives of the use of selected methods of processing and analysis of digital images, including techniques for improving the quality of images, segmentation, morphological transformation, pattern recognition and simulation of physical phenomena in the structures of materials are described.[b]Keywords[/b]: image analysis, surface layer, artificial intelligence, fuzzy logic

Control of Alq3 wetting layer thickness via substrate surface functionalization.

Science.gov (United States)

Tsoi, Shufen; Szeto, Bryan; Fleischauer, Michael D; Veinot, Jonathan G C; Brett, Michael J

2007-06-05

The effects of substrate surface energy and vapor deposition rate on the initial growth of porous columnar tris(8-hydroxyquinoline)aluminum (Alq3) nanostructures were investigated. Alq3 nanostructures thermally evaporated onto as-supplied Si substrates bearing an oxide were observed to form a solid wetting layer, likely caused by an interfacial energy mismatch between the substrate and Alq3. Wetting layer thickness control is important for potential optoelectronic applications. A dramatic decrease in wetting layer thickness was achieved by depositing Alq3 onto alkyltrichlorosilane-derivatized Si/oxide substrates. Similar effects were noted with increasing deposition rates. These two effects enable tailoring of the wetting layer thickness.

UV and plasma treatment of thin silver layers and glass surfaces

Energy Technology Data Exchange (ETDEWEB)

Hluschi, J.H. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Helmke, A. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Roth, P. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Boewer, R. [Interpane Glasbeschichtungsgesellschaft mbH and Co KG, Sohnreystr. 21, D-37697 Lauenfoerde (Germany); Herlitze, L. [Interpane Glasbeschichtungsgesellschaft mbH and Co KG, Sohnreystr. 21, D-37697 Lauenfoerde (Germany); Vioel, W. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany)]. E-mail: vioel@hawk-hhg.de

2006-11-10

Thin silver layers can be modified by treatment with UV radiation or a plasma discharge. UV treatment at a wavelength of {lambda}=308 -bar nm improves the layer properties, thus leading to an enhancement of the layers IR reflectivity. For the purpose of in situ-measurement the sheet resistance is recorded during the process. Due to the Hagen-Rubens-Relation [E. Hagen, H. Rubens, Ann. Phys. 11 (1903) 873]-bar the sheet resistance is linked to the IR reflectivity of thin metal-films. A pretreatment of uncoated glass using a dielectric barrier discharge activates and cleans its surface, thus leading to an increase in adhesion of thin layers.

UV and plasma treatment of thin silver layers and glass surfaces

International Nuclear Information System (INIS)

Hluschi, J.H.; Helmke, A.; Roth, P.; Boewer, R.; Herlitze, L.; Vioel, W.

2006-01-01

Thin silver layers can be modified by treatment with UV radiation or a plasma discharge. UV treatment at a wavelength of λ=308 -bar nm improves the layer properties, thus leading to an enhancement of the layers IR reflectivity. For the purpose of in situ-measurement the sheet resistance is recorded during the process. Due to the Hagen-Rubens-Relation [E. Hagen, H. Rubens, Ann. Phys. 11 (1903) 873]-bar the sheet resistance is linked to the IR reflectivity of thin metal-films. A pretreatment of uncoated glass using a dielectric barrier discharge activates and cleans its surface, thus leading to an increase in adhesion of thin layers

Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

Science.gov (United States)

Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.;

Success and Motivation -a Way to Motivate ESL Readers in Chinese Private Colleges

Institute of Scientific and Technical Information of China (English)

李艳

2014-01-01

Motivation refers to what and how an individual chooses to do. This essay explores the way to motivate ESL readers in private colleges and concludes that teachers should create opportunities for students to experience success as well as improve their self-efficacy.

SEM Analysis of MTAD Efficacy for Smear Layer Removal from Periodontally Affected Root Surfaces

Directory of Open Access Journals (Sweden)

R. K. Tabor

2011-12-01

Full Text Available Objective: Biopure® MTAD (Dentsply Tulsa Dental, USA has been developed as a final irrigant following root canal shaping to remove intracanal smear layer. Many of the unique properties of MTAD potentially transfer to the conditioning process of tooth roots during periodontal therapy. The aim of this ex vivo studywas to evaluate the effect of MTAD on the removal of smear layer from root surfaces.Materials and Methods: Thirty two longitudinally sectioned specimens from 16 freshly extracted teeth diagnosed with advanced periodontal disease were divided into four groups. In group 1 and 2, the root surfaces were scaled using Gracey curettes. In group 3 and 4, 0.5 mm of the root surface was removed using a fissure bur. The specimens in group 1 and 3 were then irrigated by normal saline. Thespecimens in groups 2 and 4 were irrigated with Biopure MTAD.All specimens were prepared for SEM and scored according to the presence of smear layer.Results: MTAD significantly increased (P=0.001 the smear layer removal in both groups 2 and 4 compared to the associated control groups, in which only saline was used.Conclusion: MTAD increased the removal of the smear layer from periodontally affected root surfaces. Use of MTAD as a periodontal conditioner may be suggested.

X-ray spectrum microanalysis of copper and stainless steel surface layer after electroerosion machining

International Nuclear Information System (INIS)

Abdukarimov, Eh.T.; Saidinov, S.Ya.

1989-01-01

The results of experimental investigations of the surface layer of copper and steel 12Kh18N10T after electroerrosion treatment by a rotating tungsten electrode in natural and distilled water are presented. It is established that the quantity of electrode material transferred to the surface of the steel treated grows with the spark discharge energy increase. Tungsten concentration in the surface layer reaches 5-10% with the average depth of penetration 40-50 μm

Dematerialization and Deformalization of the EFL/ESL Textbook - Literature Review and Relevant Issues

Science.gov (United States)

Meurant, Robert C.

Rapid development and critical convergence of Information Communication Technologies is radically impacting education, particularly in second language acquisition, where the sudden availability of multimedia content and immediacy of distance communication offer specific advantage. The language classroom is evolving to integrate computer-mediated learning and communication with traditional schooling; digitization and the Internet mean the textbook is evolving from inert hard copy that is consumed, to dynamic e-texts that students participate in. The emergence of English as a Global Language, with the primary role of English on the Internet, means that the transition from fixed hard copy to fluid online digital environment is particularly evident in EFL/ESL. I review research, trace ways in which this transition occurs, and speculate on how, under the impact of ICTs and their convergence, the EFL/ESL textbook will reform, and may even disappear as a stand-alone entity.

Bloch Surface Waves Using Graphene Layers: An Approach toward In-Plane Photodetectors

Directory of Open Access Journals (Sweden)

Richa Dubey

2018-03-01

Full Text Available A dielectric multilayer platform was investigated as a foundation for two-dimensional optics. In this paper, we present, to the best of our knowledge, the first experimental demonstration of absorption of Bloch surface waves in the presence of graphene layers. Graphene is initially grown on a Cu foil via Chemical Vapor Deposition and transferred layer by layer by a wet-transfer method using poly(methyl methacrylate, (PMMA. We exploit total internal reflection configuration and multi-heterodyne scanning near-field optical microscopy as a far-field coupling method and near-field characterization tool, respectively. The absorption is quantified in terms of propagation lengths of Bloch surface waves. A significant drop in the propagation length of the BSWs is observed in the presence of graphene layers. The propagation length of BSWs in bare multilayer is reduced to 17 times shorter in presence of graphene monolayer, and 23 times shorter for graphene bilayer.

Thickened boundary layer theory for air film drag reduction on a van body surface

Science.gov (United States)

Xie, Xiaopeng; Cao, Lifeng; Huang, Heng

2018-05-01

To elucidate drag reduction mechanism on a van body surface under air film condition, a thickened boundary layer theory was proposed and a frictional resistance calculation model of the van body surface was established. The frictional resistance on the van body surface was calculated with different parameters of air film thickness. In addition, the frictional resistance of the van body surface under the air film condition was analyzed by computational fluid dynamics (CFD) simulation and different air film states that influenced the friction resistance on the van body surface were discussed. As supported by the CFD simulation results, the thickened boundary layer theory may provide reference for practical application of air film drag reduction on a van body surface.

Placement, Progress, and Promotion: ESL Assessment in California's Adult Schools

Science.gov (United States)

Gonzalves, Lisa

2017-01-01

In California adult schools, standardized language assessments are typically administered to adult English as a second language (ESL) students upon enrollment; students then take these same state-approved tests throughout the academic year to demonstrate progress. As these tests assess only listening and reading skills, schools may use their own…

Surface acoustic waves in acoustic superlattice lithium niobate coated with a waveguide layer

Science.gov (United States)

Yang, G. Y.; Du, J. K.; Huang, B.; Jin, Y. A.; Xu, M. H.

2017-04-01

The effects of the waveguide layer on the band structure of Rayleigh waves are studied in this work based on a one-dimensional acoustic superlattice lithium niobate substrate coated with a waveguide layer. The present phononic structure is formed by the periodic domain-inverted single crystal that is the Z-cut lithium niobate substrate with a waveguide layer on the upper surface. The plane wave expansion method (PWE) is adopted to determine the band gap behavior of the phononic structure and validated by the finite element method (FEM). The FEM is also used to investigate the transmission of Rayleigh waves in the phononic structure with the interdigital transducers by means of the commercial package COMSOL. The results show that, although there is a homogeneous waveguide layer on the surface, the band gap of Rayleigh waves still exist. It is also found that increasing the thickness of the waveguide layer, the band width narrows and the band structure shifts to lower frequency. The present approach can be taken as an efficient tool in designing of phononic structures with waveguide layer.

Surface acoustic waves in acoustic superlattice lithium niobate coated with a waveguide layer

Directory of Open Access Journals (Sweden)

G. Y. Yang

2017-04-01

Full Text Available The effects of the waveguide layer on the band structure of Rayleigh waves are studied in this work based on a one-dimensional acoustic superlattice lithium niobate substrate coated with a waveguide layer. The present phononic structure is formed by the periodic domain-inverted single crystal that is the Z-cut lithium niobate substrate with a waveguide layer on the upper surface. The plane wave expansion method (PWE is adopted to determine the band gap behavior of the phononic structure and validated by the finite element method (FEM. The FEM is also used to investigate the transmission of Rayleigh waves in the phononic structure with the interdigital transducers by means of the commercial package COMSOL. The results show that, although there is a homogeneous waveguide layer on the surface, the band gap of Rayleigh waves still exist. It is also found that increasing the thickness of the waveguide layer, the band width narrows and the band structure shifts to lower frequency. The present approach can be taken as an efficient tool in designing of phononic structures with waveguide layer.

Spinel-structured surface layers for facile Li ion transport and improved chemical stability of lithium manganese oxide spinel

Energy Technology Data Exchange (ETDEWEB)

Lee, Hae Ri [Center for Energy Convergence Research, Korea Institute of Science Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Seo, Hyo Ree; Lee, Boeun; Cho, Byung Won [Center for Energy Convergence Research, Korea Institute of Science Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Kwan-Young [Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Oh, Si Hyoung, E-mail: sho74@kist.re.kr [Center for Energy Convergence Research, Korea Institute of Science Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

2017-01-15

Graphical abstract: Strategically-designed spinel-structured nano-scale surface layer, LiM{sub x}Mn{sup IV}{sub 1−x}O{sub 4}, featuring a high Li{sup +} ion conductivity and a good chemical stability was applied on Al-doped LiMn{sub 2}O{sub 4} spinel for the drastic improvement of the electrochemical performance at the elevated temperature as a promising cathode material for lithium rechargeable batteries. - Highlights: • Spinel-structured surface layer with a high Li-ion conductivity and a good chemical stability was prepared. • Simple wet process was developed to apply nano-scale surface layer on aluminum doped lithium manganese oxide spinel. • The properties of nano-scale surface layer were characterized by analytical tools including GITT, HR-TEM and XAS. • Materials with surface coating layer exhibit an excellent electrochemical performance at the elevated temperature. - Abstract: Li-ion conducting spinel-structured oxide layer with a manganese oxidation state close to being tetravalent was prepared on aluminum-doped lithium manganese oxide spinel for improving the electrochemical performances at the elevated temperatures. This nanoscale surface layer provides a good ionic conduction path for lithium ion transport to the core and also serves as an excellent chemical barrier for protecting the high-capacity core material from manganese dissolution into the electrolyte. In this work, a simple wet process was employed to prepare thin LiAlMnO{sub 4} and LiMg{sub 0.5}Mn{sub 1.5}O{sub 4} layers on the surface of LiAl{sub 0.1}Mn{sub 1.9}O{sub 4}. X-ray absorption studies revealed an oxidation state close to tetravalent manganese on the surface layer of coated materials. Materials with these surface coating layers exhibited excellent capacity retentions superior to the bare material, without undermining the lithium ion transport characteristics and the high rate performances.

Study on the influence of carbon monoxide to the surface oxide layer of uranium metal

International Nuclear Information System (INIS)

Wang Xiaolin; Duan Rongliang; Fu Yibei; Xie Renshou; Zuo Changming; Zhao Chunpei; Chen Hong

1997-01-01

The influence of carbon monoxide to the surface oxide layer of uranium metal has been studied by X-ray photoelectron spectroscopy (XPS) and gas chromatography (GC). Carbon monoxide adsorption on the oxide layer resulted in U4f peak shifting to the lower binding energy. The content of oxygen in the oxide is decreased and the atomic ratio (O/U) is decreased by 7.2%. The amount of carbon dioxide in the atmosphere after the surface reaction is increased by 11.0%. The investigation indicates that the surface layer can prevent the further oxidation uranium metal in the atmosphere of carbon monoxide

2nd international conference on ion beam surface layer analysis

International Nuclear Information System (INIS)

1975-01-01

The papers of this conference are concerned with the fundamental aspects and with the application of surface layer analysis. It is reported amongst others about backscattering analysis, Auger electron spectroscopy, channelling and microprobe. (HPOE) [de

Influence of surface layer removal of shade guide tabs on the measured color by spectrophotometer and spectroradiometer.

Science.gov (United States)

Kim, Jin-Cheol; Yu, Bin; Lee, Yong-Keun

2008-12-01

To determine the changes in color parameters of Vitapan 3D-Master shade guide tabs by a spectrophotometer (SP) or a spectroradiometer (SR), and by the removal of the surface layer of the tabs that was performed to make a flat measuring surface for the SP color measurement. Color of the shade tabs was measured before and after removing the surface layer of the tabs using SP and SR. Correlations between the color parameters between the original (OR) and the surface layer removed (RM) tabs and between the SP and the SR measurements were determined (alpha=0.05). Based on SP, the lightness, chroma, CIE a* and b* values measured after the surface layer removal were higher than those of the original tabs except a few cases. Based on SR, the chroma and CIE a* and b* values measured after surface layer removal were higher than those of the original tabs except a few cases; however, in case of the lightness, the changes varied by the shade designation. Type of instrument influenced the changes in color parameters based on paired t-test (pspectrophotometer or a spectroradiometer, measurement protocols should be specified because color difference by the surface layer removal and the instrument was high.

More than a "Basic Skill": Breaking down the Complexities of Summarizing for ABE/ESL Learners

Science.gov (United States)

Ouellette-Schramm, Jennifer

2015-01-01

This article describes the complex cognitive and linguistic challenges of summarizing expository text at vocabulary, syntactic, and rhetorical levels. It then outlines activities to help ABE/ESL learners develop corresponding skills.

Atomic layer-by-layer oxidation of Ge (100) and (111) surfaces by plasma post oxidation of Al2O3/Ge structures

International Nuclear Information System (INIS)

Zhang, Rui; Huang, Po-Chin; Lin, Ju-Chin; Takenaka, Mitsuru; Takagi, Shinichi

2013-01-01

The ultrathin GeO x /Ge interfaces formed on Ge (100) and (111) surfaces by applying plasma post oxidation to thin Al 2 O 3 /Ge structures are characterized in detail using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy. It is found that the XPS signals assigned to Ge 1+ and the 2+ states in the GeO x layers by post plasma oxidation have oscillating behaviors on Ge (100) surfaces in a period of ∼0.3 nm with an increase in the GeO x thickness. Additionally, the oscillations of the signals assigned to Ge 1+ and 2+ states show opposite phase to each other. The similar oscillation behaviors are also confirmed on Ge (111) surfaces for Ge 1+ and 3+ states in a period of ∼0.5 nm. These phenomena can be strongly regarded as an evidence of the atomic layer-by-layer oxidation of GeO x /Ge interfaces on Ge (100) and (111) surfaces.

A three-layer model of self-assembly induced surface-energy variation experimentally extracted by using nanomechanically sensitive cantilevers

International Nuclear Information System (INIS)

Zuo Guomin; Li Xinxin

2011-01-01

This research is aimed at elucidating surface-energy (or interfacial energy) variation during the process of molecule-layer self-assembly on a solid surface. A quasi-quantitative plotting model is proposed and established to distinguish the surface-energy variation contributed by the three characteristic layers of a thiol-on-gold self-assembled monolayer (SAM), namely the assembly-medium correlative gold/head-group layer, the chain/chain interaction layer and the tail/medium layer, respectively. The data for building the model are experimentally extracted from a set of correlative thiol self-assemblies in different media. The variation in surface-energy during self-assembly is obtained by in situ recording of the self-assembly induced nanomechanical surface-stress using integrated micro-cantilever sensors. Based on the correlative self-assembly experiment, and by using the nanomechanically sensitive self-sensing cantilevers to monitor the self-assembly induced surface-stressin situ, the experimentally extracted separate contributions of the three layers to the overall surface-energy change aid a comprehensive understanding of the self-assembly mechanism. Moreover, the quasi-quantitative modeling method is helpful for optimal design, molecule synthesis and performance evaluation of molecule self-assembly for application-specific surface functionalization.

Effect of Cholesterol on the Stability and Lubrication Efficiency of Phosphatidylcholine Surface Layers

NARCIS (Netherlands)

Sorkin, Raya; Kampf, Nir; Klein, Jacob

2017-01-01

The lubrication properties of saturated PC lipid vesicles containing high cholesterol content under high loads were examined by detailed surface force balance measurements of normal and shear forces between two surface-attached lipid layers. Forces between two opposing mica surfaces bearing

Exploring ESL Teacher Beliefs and Classroom Practices of CLT: A Case Study

Science.gov (United States)

Rahman, Mohammad Mosiur; Singh, Manjet Kaur Mehar; Pandian, Ambigapathy

2018-01-01

This paper presents a case study that investigated and compared the stated beliefs and observed classroom practices relating to Communicative Language Teaching (CLT) of two ESL teachers. The findings of the study revealed that both the teachers hold similar complex beliefs that mostly contradict the philosophy of CLT. The practices were not in…

In situ evaluation of density, viscosity, and thickness of adsorbed soft layers by combined surface acoustic wave and surface plasmon resonance.

Science.gov (United States)

Francis, Laurent A; Friedt, Jean-Michel; Zhou, Cheng; Bertrand, Patrick

2006-06-15

We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity, and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized gold-coated sensing area is the acoustic method, while surface plasmon resonance (SPR) on the same gold surface as the optical method is monitored simultaneously in a single setup for the real-time and label-free measurement of the parameters of adsorbed soft layers, which means for layers with a predominant viscous behavior. A general mathematical modeling in equivalent viscoelastic transmission lines is presented to determine the correlation between experimental SAW signal shifts and the waveguide structure including the presence of the adsorbed layer and the supporting liquid from which it segregates. A methodology is presented to identify from SAW and SPR simulations the parameters representatives of the soft layer. During the absorption of a soft layer, thickness or viscosity changes are observed in the experimental ratio of the SAW signal attenuation to the SAW signal phase and are correlated with the theoretical model. As application example, the simulation method is applied to study the thermal behavior of physisorbed PNIPAAm, a polymer whose conformation is sensitive to temperature, under a cycling variation of temperature between 20 and 40 degrees C. Under the assumption of the bulk density and the bulk refractive index of PNIPAAm, thickness and viscosity of the film are obtained from simulations; the viscosity is correlated to the solvent content of the physisorbed layer.

Specific Features of Chip Making and Work-piece Surface Layer Formation in Machining Thermal Coatings

Directory of Open Access Journals (Sweden)

V. M. Yaroslavtsev

2016-01-01

Full Text Available A wide range of unique engineering structural and performance properties inherent in metallic composites characterizes wear- and erosion-resistant high-temperature coatings made by thermal spraying methods. This allows their use both in manufacturing processes to enhance the wear strength of products, which have to operate under the cyclic loading, high contact pressures, corrosion and high temperatures and in product renewal.Thermal coatings contribute to the qualitative improvement of the technical level of production and product restoration using the ceramic composite materials. However, the possibility to have a significantly increased product performance, reduce their factory labour hours and materials/output ratio in manufacturing and restoration is largely dependent on the degree of the surface layer quality of products at their finishing stage, which is usually provided by different kinds of machining.When machining the plasma-sprayed thermal coatings, a removing process of the cut-off layer material is determined by its distinctive features such as a layered structure, high internal stresses, low ductility material, high tendency to the surface layer strengthening and rehardening, porosity, high abrasive properties, etc. When coatings are machined these coating properties result in specific characteristics of chip formation and conditions for formation of the billet surface layer.The chip formation of plasma-sprayed coatings was studied at micro-velocities using an experimental tool-setting microscope-based setup, created in BMSTU. The setup allowed simultaneous recording both the individual stages (phases of the chip formation process and the operating force factors.It is found that formation of individual chip elements comes with the multiple micro-cracks that cause chipping-off the small particles of material. The emerging main crack in the cut-off layer of material leads to separation of the largest chip element. Then all the stages

Changes of surface layer of nitrogen-implanted AISI316L stainless steel

International Nuclear Information System (INIS)

Budzynski, P.; Polanski, K.; Kobzev, A.P.

2007-01-01

The effects of nitrogen ion implantation into AISI316L stainless steel on friction, wear, and microhardness have been investigated at an energy level of 125 keV at a fluence of 1·10 17 - 1·10 18 N/cm 2 . The composition of the surface layer was investigated by RBS, XRD (GXRD), SEM and EDX. The friction coefficient and abrasive wear rate of the stainless steel were measured in the atmospheres of air, oxygen, argon, and in vacuum. As follows from the investigations, there is an increase in resistance to frictional wear in the studied samples after implantation; however, these changes are of different characters in various atmospheres. The largest decrease in wear was observed during tests in the air, and the largest reduction in the value of the friction coefficient for all implanted samples was obtained during tests in the argon atmosphere. Tribological tests revealed larger contents of nitrogen, carbon, and oxygen in the products of surface layer wear than in the surface layer itself of the sample directly after implantation

Local thermal property analysis by scanning thermal microscopy of an ultrafine-grained copper surface layer produced by surface mechanical attrition treatment

Energy Technology Data Exchange (ETDEWEB)

Guo, F.A. [Suzhou Institute for Nonferrous Metals Processing Technology, No. 200 Shenxu Road, Suzhou Industrial Park, Suzhou 215021 (China) and Unite de Thermique et d' Analyse Physique, Laboratoire d' Energetique et d' Optique, Universite de Reims, BP 1039, 51687 Reims Cedex 2 (France)]. E-mail: guofuan@yahoo.com; JI, Y.L. [Suzhou Institute for Nonferrous Metals Processing Technology, No. 200 Shenxu Road, Suzhou Industrial Park, Suzhou 215021 (China); Trannoy, N. [Unite de Thermique et d' Analyse Physique, Laboratoire d' Energetique et d' Optique, Universite de Reims, BP 1039, 51687 Reims Cedex 2 (France); Lu, J. [LASMIS, Universite de Technologie de Troyes, 12 Rue Marie Curie, Troyes 10010 (France)

2006-06-15

Scanning thermal microscopy (SThM) was used to map thermal conductivity images in an ultrafine-grained copper surface layer produced by surface mechanical attrition treatment (SMAT). It is found that the deformed surface layer shows different thermal conductivities that strongly depend on the grain size of the microstructure: the thermal conductivity of the nanostructured surface layer decreases obviously when compared with that of the coarse-grained matrix of the sample. The role of the grain boundaries in thermal conduction is analyzed in correlation with the heat conduction mechanism in pure metal. A theoretical approach, based on this investigation, was used to calculate the heat flow from the probe tip to the sample and then estimate the thermal conductivities at different scanning positions. Experimental results and theoretical calculation demonstrate that SThM can be used as a tool for the thermal property and microstructural analysis of ultrafine-grained microstructures.

Reaching teen farm workers with health and safety information: an evaluation of a high school ESL curriculum.

Science.gov (United States)

Teran, S; Strochlic, R; Bush, D; Baker, R; Meyers, J

2008-04-01

While childhood agricultural injury has long been recognized as an important public health issue, most research has focused on family farms and there have not been many interventions targeting hired youth. This study evaluated the impact of a high school English as a Second Language (ESL) curriculum, designed to provide teen agricultural workers with the knowledge and tools to protect their health and safety in the fields. Using a quasi-experimental design, the research consisted of two intervention groups and a comparison group, and included over 2,000 students from communities that lead California in agricultural production. The research findings revealed that the curriculum had significant impact in terms of increases in knowledge and attitudes, and nearly half of those interviewed after a summer of working in the fields reported implementing new behaviors to protect their health and safety. The curriculum also had extended effects in the broader community, as the majority of students reported sharing the new information with others. The study found that a school-based ESL curriculum is an effective intervention to reach and educate teen farm workers and that ESL classes can serve as a much-needed access point for young farm workers.

The laser surface alloying of the surface layer of the plain carbon steel

International Nuclear Information System (INIS)

Woldan, A.; Kusinski, J.

2003-01-01

The paper describes the microstructure and properties (chemical composition, microhardness and the effect of tribological test of the surface laser alloyed layer with tantalum. Scanning electron microscopy examinations show structure, which consist of martensite and Ta2C carbides. Samples covered with Ta and the carbon containing binder showed after laser alloying higher hardness than in case of using silicon-containing binder. (author)

Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

Energy Technology Data Exchange (ETDEWEB)

Varault, S. [ONERA—The French Aerospace Lab 2, Avenue Edouard Belin, BP4025, 31055 Toulouse Cedex (France); Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9 (France); Gabard, B. [ONERA—The French Aerospace Lab 2, Avenue Edouard Belin, BP4025, 31055 Toulouse Cedex (France); STAE—4, Rue Emile Monso, BP84234, 31030 Toulouse Cedex 4 (France); Crépin, T.; Bolioli, S. [ONERA—The French Aerospace Lab 2, Avenue Edouard Belin, BP4025, 31055 Toulouse Cedex (France); Sokoloff, J. [Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9 (France)

2014-02-28

We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiation pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide.

Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

International Nuclear Information System (INIS)

Varault, S.; Gabard, B.; Crépin, T.; Bolioli, S.; Sokoloff, J.

2014-01-01

We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiation pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide

New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

International Nuclear Information System (INIS)

Ismail, R.; Tauviqirrahman, M.; Jamari; Schipper, D. J.

2009-01-01

This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio‐degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser‐print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running‐in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.

New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

Science.gov (United States)

Ismail, R.; Tauviqirrahman, M.; Jamari, Jamari; Schipper, D. J.

2009-09-01

This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio-degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser-print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running-in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.

A quality-control procedure for surface temperature and surface layer inversion in the XBT data archive from the Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Pankajakshan, T.; Ghosh, A.K.; Pattanaik, J.; Ratnakaran, L.

and surface layer temperature inversion. XBT surface temperatrues (XST) are compared with the surface temperature from simultaneous CTD observations from four cruises and the former were found to be erroneous in a number of stations. XSTs are usually corrected...

Structural and technological formation of surface nanostructured Ti-Ni-Mo layers by high-speed gas-flame spraying

Directory of Open Access Journals (Sweden)

Blednova Zhesfina

2015-01-01

Full Text Available The article covers a complex method of forming surface-modified layers using materials with shape memory effect (SME based on TiNiMo including pre-grinding and mechanical activation of the coating material, high-speed gas-flame spraying of Ni adhesive layer and subsequent TiNiMo spraying with molybdenum content up to 2%, thermal and thermomechanical processing in a single technological cycle. This allowed forming nanostructured surface layers with a high level of functional mechanical and performance properties. We defined control parameters of surface steel modification using material with shape memory effect based on TiNiMo, which monitor the structural material state, both at the stage of spraying, and during subsequent combined treatment, which allows affecting purposefully on the functional properties of the SME surface layer. Test results of samples before coating and after surface modification with TiNiMo in the seawater indicate that surface modification brings to a slower damage accumulation and to increase of steel J91171 endurance limit in seawater by 45%. Based on complex metallophysical research of surface layers we obtained new data about nano-sized composition “steel - Ni - TiNiMo”.

Evolution of the lower planetary boundary layer over strongly contrasting surfaces

International Nuclear Information System (INIS)

Coulter, R.L.; Gao, W.; Martin, T.J.; Shannon, J.D.; Doran, J.C.; Hubbe, J.M.; Shaw, W.M.

1992-01-01

In a multilaboratory field study held near Boardman in northeastern Oregon in June 1991, various properties of the surface and lower atmospheric boundary layer over heavily irrigated cropland and adjacent desert steppe were investigated in the initial campaign of the Atmospheric Radiation Measurement (ARM) program. The locale was selected because its disparate characteristics over various spatial scales stress the ability of general circulation models (GCMS) to describe lower boundary conditions, particularly across the discontinuity between desert (in which turbulent flux of heat must be primarily as sensible heat) and large irrigated tracts (in which turbulent flux of latent heat should be the larger term). This campaign of ARM seeks to increase knowledge in three critical areas: (1) determination of the relationships between surface heat fluxes measured over multiple scales and the controlling surface parameters within each scale, (2) integration of local and nearly local heat flux estimates to produce estimates appropriate for GCM grid cells of 100-200 km horizontal dimension, and (3) characterization of the growth and development of the atmospheric boundary layer near transitions between surfaces with strongly contrasting moisture availabilities

Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification.

Science.gov (United States)

Lassnig, R; Hollerer, M; Striedinger, B; Fian, A; Stadlober, B; Winkler, A

2015-11-01

In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p ++ -silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3-4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact-channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility.

Output, Input Enhancement, and the Noticing Hypothesis: An Experimental Study on ESL Relativization.

Science.gov (United States)

Izumi, Shinichi

2002-01-01

Investigates potentially facilitative effects of internal and external attention-drawing devices--output and visual input enhancement--on acquisition of English relativization by adult English-as-a-Second-Language (ESL) learners. Addresses whether producing output promotes noticing of formal elements in target language input and affects subsequent…

Microstructure and Texture in Surface Deformation Layer of Al-Zn-Mg-Cu Alloy Processed by Milling

Directory of Open Access Journals (Sweden)

CHEN Yanxia

2017-12-01

Full Text Available The microstructural and crystallographic features of the surface deformation layer in Al-Zn-Mg-Cu alloy induced by milling were investigated by means of transmission electron microscopy (TEM and precession electron diffraction (PED assisted nanoscale orientation mapping. The result shows that the surface deformation layer is composed by the top surface of equiaxed nanograins/ultrafine grains and the subsurface of lamellar nanograins/ultrafine grains surrounded by coarse grain boundary precipitates (GBPs. The recrystallized nanograins/ultrafine grains in the deformation layer show direct evidence that dynamic recrystallization plays an important role in grain refining process. The GBPs and grain interior precipitates (GIPs show a great difference in size and density with the matrix due to the thermally and mechanically induced precipitate redistribution. The crystallographic texture of the surface deformation layer is proved to be a mixture of approximate copper{112}, rotated cube{001} and F {111}. The severe shear deformation of the surface induced by milling is responsible for the texture evolution.