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285 results on '"Dean Ruth"'

1. Continuous synthesis of high-entropy alloy nanoparticles by in-flight alloying of elemental metals

Author

Keun Su Kim, Martin Couillard, Ziqi Tang, Homin Shin, Daniel Poitras, Changjun Cheng, Olga Naboka, Dean Ruth, Mark Plunkett, Lixin Chen, Liliana Gaburici, Thomas Lacelle, Michel Nganbe, and Yu Zou

Subjects
Science
Abstract

Abstract High-entropy alloy (HEA) nanoparticles (NPs) exhibit unusual combinations of functional properties. However, their scalable synthesis remains a significant challenge requiring extreme fabrication conditions. Metal salts are often employed as precursors because of their low decomposition temperatures, yet contain potential impurities. Here, we propose an ultrafast ( 5000 K) is employed for rapid heating/cooling (103 − 105 K s−1), and demonstrates the synthesis of CrFeCoNiMo HEA NPs ( ~ 50 nm) at a high rate approaching 35 g h−1 with a conversion efficiency of 42%. Our thermofluid simulation reveals that the properties of HEA NPs can be tailored by the plasma gas which affects the thermal history of NPs. The HEA NPs demonstrate an excellent light absorption of > 96% over a wide spectrum, representing great potential for photothermal conversion of solar energy at large scales. Our work shows that the thermal plasma process developed could provide a promising route towards industrial scale production of HEA NPs.

Published
2024
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4. Ethical-Clinical Tensions in Clinical Practice.

Author

Dean, Ruth Grossman and Rhodes, Margaret L.

Abstract

Focuses on boundaries clinicians draw between ethical and clinical responses in their work. Focuses particularly on psychodynamic practice in presenting three clinical vignettes. Vignettes highlight worker responses to one client's stealing and feelings of entitlement about it, another client's racism, and another's sexual abuse by previous therapist. Recommends that ethical deliberation be more explicit focus of treatment. (Author/NB)

Published
1992

6. Memoirs of Fellows and Corresponding Fellows of the Medieval Academy of America

Author

Boyle, Leonard F., Dean, Ruth J., Meyvaert, Paul, Rouse, Richard H., Bloomfield, Morton W., Brault, Gerard J., Roach, William J., Brentano, Robert, Kristeller, Paul O., Davis, Charles T., Courtenay, William J., Setton, Kenneth M., Strayer, Joseph R., Thorne, Samuel E., and Cuttino, George

Published
1987

7. Memoirs of Fellows and Corresponding Fellows of the Medieval Academy of America

Author

Courtenay, William J., Cranz, F. Edward, Rosenthal, Franz, Benson, Robert L., Marti, Berthe, Bisson, T. N., Benson, Larry D., Kane, George, Robinson, Fred C., Boyle, Leonard, Tierney, Brian, Kuttner, Stephan, Hanning, Robert, Pope, John, Thorne, Samuel, Baldwin, John W., Andersson, Theodore M., Lewis, Archibald R., Pelikan, Jaroslav, Herlihy, David, Leyerle, John, Fisher, John H., Dean, Ruth J., Roach, William J., Wenzel, Siegfried, Lewis, Archibald L., Lyon, Bryce, Cuttino, G. P., Benton, John F., Clagett, Marshall, Rouse, Richard H., and Grant, Edward

Published
1988

8. Memoirs of Fellows and Corresponding Fellows of the Medieval Academy of America

Author

Meyvaert, Paul, Whiting, B. J., Benson, Larry D., Lewis, Archibald R., Baldwin, John W., Bloomfield, Morton, Brentano, Robert, Herlihy, David, Courtenay, William J., Bisson, Thomas N., Bishko, C. J., Dean, Ruth J., Rouse, Richard H., Kaske, Robert E., Springer, Otto, and Andersson, Theodore M.

Published
1985

9. Memoirs of Fellows and Corresponding Fellows of the Medieval Academy of America

Author

Cranz, F. Edward, Dean, Ruth J., Lumiansky, Robert M., Kristeller, Paul Oskar, Rosenthal, Franz, Setton, Kenneth M., Strayer, Joseph R., Lopez, Robert S., Grant, Edward, Gabriel, Astrik L., Robinson, Fred C., Courtenay, William J., Howard, Donald R., Kaske, Robert E., Ferrante, Joan M., Goffart, Walter, Meyvaert, Paul, and Constable, Giles

Published
1986

14. Memoirs of Fellows and Corresponding Fellows of the Medieval Academy of America

Author

Lumiansky, Robert M., Roach, William J., Wenzel, Siegfried, Bloomfield, Morton W., Leyerle, John F., Kane, George, Kristeller, Paul O., Meyvaert, Paul, Boyle, Leonard E., Kibre, Pearl, Strayer, Joseph R., White,, Lynn, Rouse, Richard H., Gabriel, Astrik L., Dean, Ruth J., Benson, Larry D., Cranz, F. Edward, Whiting, B. J., Raftis, J. Ambrose, Shook, L. K., and Leyerle, John

Published
1982

29. Scalable gas-phase purification of boron nitride nanotubes by selective chlorine etching

Author

Yadienka Martinez Rubi, Hyunjin Cho, Jingwen Guan, Keun Su Kim, Dean Ruth, Christopher T. Kingston, Michael B. Jakubinek, Stéphane Dénommée, Benoit Simard, Christa M. Homenick, Martin Couillard, Iannitto Robyn, Andreas Brinkmann, Zygmunt J. Jakubek, Mark Plunkett, and Steven C. Walker

Subjects
nitrides, Materials science, purification, General Chemical Engineering, chemistry.chemical_element, ComputerApplications_COMPUTERSINOTHERSYSTEMS, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Gas phase, materials, chemistry.chemical_compound, Chemical engineering, chemistry, Etching (microfabrication), Boron nitride, Materials Chemistry, Chlorine, Current (fluid), 0210 nano-technology, purities, boron
Abstract

Current processes to manufacture nanotubes at commercial scales are unfortunately imperfect and commonly generate undesirable byproducts. After manufacturing, purification is necessary and is a rate and cost determining step in advancing the development of commercial products based on nanotubes. Boron nitride nanotubes (BNNTs) produced without metal catalysts from high-temperature processes are known to contain a significant amount (e.g., 50 wt %) of various boron derivatives. Herein we report a simple yet efficient and scalable process to purify these types of BNNT materials at commercial scales, from a few grams to hundreds of grams, at purity over 85 wt % in a single step. The process relies on a vertically mounted flow tube reactor and scrubber system that can be operated under pure or diluted chlorine gas flow at temperatures up to 1100 °C. The main chemical reactions driving the purification are the conversion of boron and BN derivatives into BCl3 and HCl, which are removed as gaseous species, while pristine BNNTs are left behind. The preferential etching of impurities over pristine BNNTs shows the extreme chemical resistance of BNNTs in this harsh environment and opens up new applications for this nanomaterial. The process has been examined at various temperatures, up to 1050 °C, and the resulting materials display improved BNNT purity and quality across a range of imaging and spectroscopic assessments. The recommended temperature to optimize quality with yield is 950 °C, although higher quality material is obtained at a higher temperature.

Published
2021

31. The livable house, its garden

Author

Dean, Ruth, 1889-1932, Cornell University Library, University Library, University of Illinois Urbana Champaign, and Dean, Ruth, 1889-1932

Subjects
Gardens, Landscape gardening, United States
Published
1917

32. The livable house, its garden,

Author

Dean, Ruth, Library of Congress, and Dean, Ruth

Subjects
Landscape gardening, United States
Published
1917

34. The livable house, its garden

Author

Dean, Ruth, 1889-1932, Cornell University Library, and Dean, Ruth, 1889-1932

Subjects
Gardens, Landscape gardening, United States

35. The livable house, its garden

Author

Dean, Ruth, 1889-1932, Library of Congress, and Dean, Ruth, 1889-1932

Subjects
Landscape gardening, United States

43. Social constructionism and ethics: what makes a 'better' story?

Author

Dean, Ruth G. and Rhodes, Margaret L.

Subjects
Social workers -- Practice, Constructivism (Psychology) -- Social aspects, Social service -- Psychological aspects, Professional ethics -- Study and teaching, Family and marriage, Sociology and social work
Published
1998

45. Book reviews

Author

Magee, Maggie, Howard, Helen E., Dean, Ruth Grossman, Kolodziejski, Katy, and Leader, Eloine

Published
1991
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48. Shame: The Underside of Narcissism

Author

Dean, Ruth Grossman

Subjects
Shame: The Underside of Narcissism (Book) -- Book reviews, Books -- Book reviews, Sociology and social work
Published
1991

49. Role of hydrogen in high-yield growth of boron nitride nanotubes at atmospheric pressure by induction thermal plasma

Author

Mark Plunkett, Christopher T. Kingston, Keun Su Kim, Dean Ruth, Martin Couillard, Benoit Simard, and Homin Shin

Subjects
Materials science, Hydrogen, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, optical emission spectroscopy, chemistry.chemical_compound, Thermal conductivity, Vaporization, boron nitride nanotubes, General Materials Science, density functional theory, Quenching, Atmospheric pressure, General Engineering, Plasma, Atmospheric temperature range, 021001 nanoscience & nanotechnology, induction thermal plasma, 0104 chemical sciences, chemistry, Chemical engineering, Boron nitride, hydrogen-catalyzed, scalable manufacturing, 0210 nano-technology, thermofluid simulation
Abstract

We recently demonstrated scalable manufacturing of boron nitride nanotubes (BNNTs) directly from hexagonal BN (hBN) powder by using induction thermal plasma, with a high-yield rate approaching 20 g/h. The main finding was that the presence of hydrogen is crucial for the high-yield growth of BNNTs. Here we investigate the detailed role of hydrogen by numerical modeling and in situ optical emission spectroscopy (OES) and reveal that both the thermofluidic fields and chemical pathways are significantly altered by hydrogen in favor of rapid growth of BNNTs. The numerical simulation indicated improved particle heating and quenching rates (∼105 K/s) due to the high thermal conductivity of hydrogen over the temperature range of 3500–4000 K. These are crucial for the complete vaporization of the hBN feedstock and rapid formation of nanosized B droplets for the subsequent BNNT growth. Hydrogen is also found to extend the active BNNT growth zone toward the reactor downstream, maintaining the gas temperature above the B solidification limit (∼2300 K) by releasing the recombination heat of H atoms, which starts at 3800 K. The OES study revealed that H radicals also stabilize B or N radicals from dissociation of the feedstock as BH and NH radicals while suppressing the formation of N2 or N2+ species. Our density functional theory calculations showed that such radicals can provide faster chemical pathways for the formation of BN compared with relatively inert N2.

Published
2019

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