Acrylic emulsion paint films: The effect of solution pH,conductivity, and ionic strength on film swelling and surfactant removal     

Courtney E. Dillon  Richard C. Wolbers 《文物保护研究》2014,59(1):52-62

To date, a limited number of aqueous conditions have been tested experimentally as potential cleaning reagents on modern acrylic paint films. Those assessed have tended to extract measurable quantities of paint film components and distort the paint films physically. In this paper the results of a series of experiments designed to examine pH, conductivity, and specific ion effects of potential aqueous cleaning solutions on a series of commercial acrylic paints are reported. A three-dimensional microscopic technique was used to characterize the physical (volume and surface roughness) changes and liquid chromatography-tandem mass spectrometry was used to characterize the chemical (extracted surfactant) changes following paint film exposure to the aqueous solution. The tested paint films in this study clearly exhibit an isotonic point below which swelling and extraction is significant, and above which the swelling and extraction is diminished. Manipulation of conductivity and the ionic species in solution can reduce both the physical film changes and surfactant extraction from acrylic paint films; while pH appears to be of limited use in controlling aqueous cleaning effects. Moreover, there seems to be a specific ion effect for both swelling and de-swelling in acrylic paint films that can be rationalized through the Hofmeister Series.  相似文献   

Barbarians at the gates: a half-century of unaffiliated users in academic libraries     

Nancy Courtney   《The Journal of Academic Librarianship》2001,27(6)

  相似文献   

建构跨学科的中国环境与资源社会学     

秦华  科特尼·弗林特 《资源科学》2012,34(6):1184-1191

环境社会学与自然资源社会学是关于社会与自然界相互关系的两个主要研究传统。目前关于这两个分支学科的讨论主要是局限在美国学术界内,而其对于其它国家环境和社会研究学科建设的借鉴作用尚未引起足够的重视,这正是本文在中国的学术背景中提出环境社会学与自然资源社会学相互融合问题的原因所在。环境社会学在中国正处于重要的学科建设阶段,垮学科的中国环境与资源社会学在投身中国"资源节约型、环境友好型"社会的建设中完全有希望实现环境社会学与自然资源社会学的实质融合。  相似文献   

Informed choice and deaf children: underpinning concepts and enduring challenges   总被引：3，自引：0，他引：3  

Young A  Carr G  Hunt R  McCracken W  Skipp A  Tattersall H 《Journal of deaf studies and deaf education》2006,11(3):322-336

  相似文献   

CALCULUS STUDENTS’ AND INSTRUCTORS’ CONCEPTUALIZATIONS OF SLOPE: A COMPARISON ACROSS ACADEMIC LEVELS     

Courtney Nagle  Deborah Moore-Russo  Janine Viglietti  Kristi Martin 《International Journal of Science and Mathematics Education》2013,11(6):1491-1515

This study considers tertiary calculus students’ and instructors’ conceptualizations of slope. Qualitative techniques were employed to classify responses to 5 items using conceptualizations of slope identified across various research settings. Students’ responses suggest that they rely on procedurally based conceptualizations of slope, showing little evidence of covariational reasoning. In contrast, instructors’ responses demonstrated a multi-dimensional understanding of slope as a functional property, which applies to real-world situations and plays an integral role in the development of key calculus concepts. While relatively diverse, the instructors’ responses seldom reported determining increasing or decreasing trends of a line from its slope. This conceptualization was used frequently by students and could help them better understand how slope ties to positive and negative derivatives. The most frequently used conceptualizations for students in this study align with past research findings on the emphasis of the secondary mathematics curriculum, supporting the possibility of cultural influences (academic and geographic) on individuals’ conceptualizations of slope. Thus, this study provides valuable insight into conceptualizations of slope and provides direction for future research on slope and the broader topic of cultural influences on mathematical meaning.  相似文献   

The Influence of Criminal Justice Major on Punitive Attitudes     

Tara O’Connor Shelley  Courtney A. Waid  Rhonda R. Dobbs 《Journal of Criminal Justice Education》2013,24(4):526-545

Students majoring in criminology and criminal justice are assumed to have more detailed and accurate knowledge about crime, criminal justice, and punishment practices than peers majoring in other disciplines. The purpose of this study was to examine if criminology/criminal justice majors were more or less punitive than students pursuing other majors at three universities using standard predictors of punitiveness that have not been consistently examined in previous research. The results indicate that criminology and criminal justice students are more punitive in the combined three‐campus sample and in two of the three‐campus samples considered separately.  相似文献   

Bodies in flux: scientific methods for negotiating medical uncertainty,C. Teston. Chicago,IL: University of Chicago Press, 2017, 243 pp., Paperback – $35/Hardcover – $105/E-Book – $35     

Chris McCracken 《Technical Communication Quarterly》2018,27(2):191-194

  相似文献   

Crowdsourcing the Virtual Reference Interview with Twitter     

Courtney L. Young 《The Reference Librarian》2014,55(2):172-174

  相似文献   

Book reviews     

Julius Gould  Keith Pavitt  Samuel McCracken 《Minerva》1973,11(2):269-281

  相似文献   

Australian higher education third party arrangements: an independent institute case study     

Austin  Denise A.  Pegram  Nigel  Hodson  Courtney  Hepplewhite  Glenda  Nelson  Belinda 《Tertiary Education and Management》2021,27(3):281-296

Tertiary Education and Management - The marked increase in transnational higher education third party arrangements in recent years represents globalizing forms of education. Third party...  相似文献