Search

Your search keyword '"Butcher, T"' showing total 219 results
Start Over Author "Butcher, T"
219 results on '"Butcher, T"'

1. Femtosecond temperature measurements of laser-shocked copper deduced from the intensity of the x-ray thermal diffuse scattering

Author

Wark, J. S., Peake, D. J., Stevens, T., Heighway, P. G., Ping, Y., Sterne, P., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., Butcher, T., Cafiso, S. Di Dio, Cerantola, V., Chantel, J., Di Cicco, A., Coleman, A. L., Collier, J., Collins, G., Comley, A. J., Coppari, F., Cowan, T. E., Cristoforetti, G., Cynn, H., Descamps, A., Dorchies, F., Duff, M. J., Dwivedi, A., Edwards, C., Eggert, J. H., Errandonea, D., Fiquet, G., Galtier, E., Garcia, A. Laso, Ginestet, H., Gizzi, L., Gleason, A., Goede, S., Gonzalez, J. M., Gorman, M. G., Harmand, M., Hartley, N., Hernandez-Gomez, C., Higginbotham, A., Höppner, H., Humphries, O. S., Husband, R. J., Hutchinson, T. M., Hwang, H., Keen, D. A., Kim, J., Koester, P., Konopkova, Z., Kraus, D., Krygier, A., Labate, L., Lazicki, A. E., Lee, Y., Liermann, H-P., Mason, P., Masruri, M., Massani, B., McBride, E. E., McGuire, C., McHardy, J. D., McGonegle, D., McWilliams, R. S., Merkel, S., Morard, G., Nagler, B., Nakatsutsumi, M., Nguyen-Cong, K., Norton, A-M., Oleynik, I. I., Otzen, C., Ozaki, N., Pandolfi, S., Pelka, A., Pereira, K. A., Phillips, J. P., Prescher, C., Preston, T., Randolph, L., Ranjan, D., Ravasio, A., Redmer, R., Rips, J., Santamaria-Perez, D., Savage, D. J., Schoelmerich, M., Schwinkendorf, J-P., Singh, S., Smith, J., Smith, R. F., Sollier, A., Spear, J., Spindloe, C., Stevenson, M., Strohm, C., Suer, T-A., Tang, M., Toncian, M., Toncian, T., Tracy, S. J., Trapananti, A., Tschentscher, T., Tyldesley, M., Vennari, C. E., Vinci, T., Vogel, S. C., Volz, T. J., Vorberger, J., Willman, J. T., Wollenweber, L., Zastrau, U., Brambrink, E., Appel, K., and McMahon, M. I.

Subjects
Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

We present 50-fs, single-shot measurements of the x-ray thermal diffuse scattering (TDS) from copper foils that have been shocked via nanosecond laser-ablation up to pressures above 135~GPa. We hence deduce the x-ray Debye-Waller (DW) factor, providing a temperature measurement. The targets were laser-shocked with the DiPOLE 100-X laser at the High Energy Density (HED) endstation of the European X-ray Free-Electron Laser (EuXFEL). Single x-ray pulses, with a photon energy of 18 keV, were scattered from the samples and recorded on Varex detectors. Despite the targets being highly textured (as evinced by large variations in the elastic scattering), and with such texture changing upon compression, the absolute intensity of the azimuthally averaged inelastic TDS between the Bragg peaks is largely insensitive to these changes, and, allowing for both Compton scattering and the low-level scattering from a sacrificial ablator layer, provides a reliable measurement of $T/\Theta_D^2$, where $\Theta_D$ is the Debye temperature. We compare our results with the predictions of the SESAME 3336 and LEOS 290 equations of state for copper, and find good agreement within experimental errors. We thus demonstrate that single-shot temperature measurements of dynamically compressed materials can be made via thermal diffuse scattering of XFEL radation., Comment: 17 pages, 9 figures in main article; 10 pages, 5 figures in supplementary material

Published
2025

2. A review of regulatory standard test methods for residential wood heaters and recommendations for their advancement

Author

Caubel, JJ, Trojanowski, R, Butcher, T, and Rapp, VH

Subjects
Engineering, Energy
Abstract

In many regions, residential wood heaters are a leading source of harmful air pollution but only satisfy a small portion of local heating demands. In response, standardized laboratory test methods have been developed to characterize and limit wood heater emissions. While these test methods are a key tool for advancing both wood heater technology and environmental regulations, many of the experimental procedures are outdated and provide few actionable insights for improving heater performance. Furthermore, these test methods vary widely around the world and may not adequately capture the performance of wood heaters operating in residences. This study presents a comprehensive review of standardized wood heater test methods to identify fundamental experimental objectives and regulated performance metrics. Using the results of this review, recommendations are provided to make the test methods more accessible and representative of residential performance, while generating actionable data to motivate heater design improvements. This study elucidates the current state of standard test methods, and the developments needed to advance clean wood heater technologies and public policies.

Published
2023

3. Magnetic Forces in Paramagnetic Fluids

Author

Butcher, T. A. and Coey, J. M. D.

Subjects
Physics - Chemical Physics, Physics - Fluid Dynamics
Abstract

An overview of the effect of a magnetic field gradient on fluids with linear magnetic susceptibilities is given. It is shown that two commonly encountered expressions, the magnetic field gradient force and the concentration gradient force for paramagnetic species in solution are equivalent for incompressible fluids. The magnetic field gradient and concentration gradient forces are approximations of the Kelvin force and Korteweg-Helmholtz force densities, respectively. The criterion for the appearance of magnetically induced convection is derived. Experimental work in which magnetically induced convection plays a role is reviewed.

Published
2022
Full Text
View/download PDF

4. Neutron Imaging of Paramagnetic Ions: Electrosorption by Carbon Aerogels and Macroscopic Magnetic Forces

Author

Butcher, T. A., Prendeville, L., Rafferty, A., Trtik, P., Boillat, P., and Coey, J. M. D.

Subjects
Physics - Chemical Physics
Abstract

The electrosorption of Gd$^{3+}$ ions from aqueous 70 mM Gd(NO$_3$)$_3$ solution in monolithic carbon aerogel electrodes was recorded by dynamic neutron imaging. The aerogels have a bimodal pore size distribution consisting of macropores and mesopores centered at 115 nm and 15 nm, respectively. After the uptake of Gd$^{3+}$ ions by the negatively charged surface of the porous structure, an inhomogeneous magnetic field was applied to the system of discharging electrodes. This led to a convective flow and confinement of Gd(NO$_3$)$_3$ solution in the magnetic field gradient. Thus, a way to desalt and capture paramagnetic ions from an initially homogeneous solution is established.

Published
2021
Full Text
View/download PDF

6. Shock compression experiments using the DiPOLE 100-X laser on the high energy density instrument at the European x-ray free electron laser: Quantitative structural analysis of liquid Sn.

Author

Gorman, M. G., McGonegle, D., Smith, R. F., Singh, S., Jenkins, T., McWilliams, R. S., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Benuzzi-Mounaix, A., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., and Butcher, T.

Subjects
FREE electron lasers, LIQUID analysis, ENERGY density, X-ray lasers, LASERS, LIQUID density
Abstract

X-ray free electron laser (XFEL) sources coupled to high-power laser systems offer an avenue to study the structural dynamics of materials at extreme pressures and temperatures. The recent commissioning of the DiPOLE 100-X laser on the high energy density (HED) instrument at the European XFEL represents the state-of-the-art in combining x-ray diffraction with laser compression, allowing for compressed materials to be probed in unprecedented detail. Here, we report quantitative structural measurements of molten Sn compressed to 85(5) GPa and ∼ 3500 K. The capabilities of the HED instrument enable liquid density measurements with an uncertainty of ∼ 1 % at conditions which are extremely challenging to reach via static compression methods. We discuss best practices for conducting liquid diffraction dynamic compression experiments and the necessary intensity corrections which allow for accurate quantitative analysis. We also provide a polyimide ablation pressure vs input laser energy for the DiPOLE 100-X drive laser which will serve future users of the HED instrument. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

8. Shock compression experiments using the DiPOLE 100-X laser on the high energy density instrument at the European x-ray free electron laser: Quantitative structural analysis of liquid Sn

Author

Gorman, M, Mcgonegle, D, Smith, R, Singh, S, Jenkins, T, Mcwilliams, R, Albertazzi, B, Ali, S, Antonelli, L, Armstrong, M, Baehtz, C, Ball, O, Banerjee, S, Belonoshko, A, Benuzzi-Mounaix, A, Bolme, C, Bouffetier, V, Briggs, R, Buakor, K, Butcher, T, Di Dio Cafiso, S, Cerantola, V, Chantel, J, Di Cicco, A, Clarke, S, Coleman, A, Collier, J, Collins, G, Comley, A, Coppari, F, Cowan, T, Cristoforetti, G, Cynn, H, Descamps, A, Dorchies, F, Duff, M, Dwivedi, A, Edwards, C, Eggert, J, Errandonea, D, Fiquet, G, Galtier, E, Laso Garcia, A, Ginestet, H, Gizzi, L, Gleason, A, Goede, S, Gonzalez, J, Harmand, M, Hartley, N, Heighway, P, Hernandez-Gomez, C, Higginbotham, A, Höppner, H, Husband, R, Hutchinson, T, Hwang, H, Lazicki, A, Keen, D, Kim, J, Koester, P, Konopkova, Z, Kraus, D, Krygier, A, Labate, L, Lee, Y, Liermann, H, Mason, P, Masruri, M, Massani, B, Mcbride, E, Mcguire, C, Mchardy, J, Merkel, S, Morard, G, Nagler, B, Nakatsutsumi, M, Nguyen-Cong, K, Norton, A, Oleynik, I, Otzen, C, Ozaki, N, Pandolfi, S, Peake, D, Pelka, A, Pereira, K, Phillips, J, Prescher, C, Preston, T, Randolph, L, Ranjan, D, Ravasio, A, Redmer, R, Rips, J, Santamaria-Perez, D, Savage, D, Schoelmerich, M, Schwinkendorf, J, Smith, J, Sollier, A, Spear, J, Spindloe, C, Stevenson, M, Strohm, C, Suer, T, Tang, M, Toncian, M, Toncian, T, Tracy, S, Trapananti, A, Tschentscher, T, Tyldesley, M, Vennari, C, Vinci, T, Vogel, S, Volz, T, Vorberger, J, Walsh, J, Wark, J, Willman, J, Wollenweber, L, Zastrau, U, Brambrink, E, Appel, K, Mcmahon, M, Gorman, M. G., McGonegle, D., Smith, R. F., Singh, S., Jenkins, T., McWilliams, R. S., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Benuzzi-Mounaix, A., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., Butcher, T., Di Dio Cafiso, S., Cerantola, V., Chantel, J., Di Cicco, A., Clarke, S., Coleman, A. L., Collier, J., Collins, G. W., Comley, A. J., Coppari, F., Cowan, T. E., Cristoforetti, G., Cynn, H., Descamps, A., Dorchies, F., Duff, M. J., Dwivedi, A., Edwards, C., Eggert, J. H., Errandonea, D., Fiquet, G., Galtier, E., Laso Garcia, A., Ginestet, H., Gizzi, L., Gleason, A., Goede, S., Gonzalez, J. M., Harmand, M., Hartley, N. J., Heighway, P. G., Hernandez-Gomez, C., Higginbotham, A., Höppner, H., Husband, R. J., Hutchinson, T. M., Hwang, H., Lazicki, A. E., Keen, D. A., Kim, J., Koester, P., Konopkova, Z., Kraus, D., Krygier, A., Labate, L., Lee, Y., Liermann, H. -P., Mason, P., Masruri, M., Massani, B., McBride, E. E., McGuire, C., McHardy, J. D., Merkel, S., Morard, G., Nagler, B., Nakatsutsumi, M., Nguyen-Cong, K., Norton, A. -M., Oleynik, I. I., Otzen, C., Ozaki, N., Pandolfi, S., Peake, D. J., Pelka, A., Pereira, K. A., Phillips, J. P., Prescher, C., Preston, T. R., Randolph, L., Ranjan, D., Ravasio, A., Redmer, R., Rips, J., Santamaria-Perez, D., Savage, D. J., Schoelmerich, M., Schwinkendorf, J. -P., Smith, J., Sollier, A., Spear, J., Spindloe, C., Stevenson, M., Strohm, C., Suer, T. -A., Tang, M., Toncian, M., Toncian, T., Tracy, S. J., Trapananti, A., Tschentscher, T., Tyldesley, M., Vennari, C. E., Vinci, T., Vogel, S. C., Volz, T. J., Vorberger, J., Walsh, J. P. S., Wark, J. S., Willman, J. T., Wollenweber, L., Zastrau, U., Brambrink, E., Appel, K., McMahon, M. I., Gorman, M, Mcgonegle, D, Smith, R, Singh, S, Jenkins, T, Mcwilliams, R, Albertazzi, B, Ali, S, Antonelli, L, Armstrong, M, Baehtz, C, Ball, O, Banerjee, S, Belonoshko, A, Benuzzi-Mounaix, A, Bolme, C, Bouffetier, V, Briggs, R, Buakor, K, Butcher, T, Di Dio Cafiso, S, Cerantola, V, Chantel, J, Di Cicco, A, Clarke, S, Coleman, A, Collier, J, Collins, G, Comley, A, Coppari, F, Cowan, T, Cristoforetti, G, Cynn, H, Descamps, A, Dorchies, F, Duff, M, Dwivedi, A, Edwards, C, Eggert, J, Errandonea, D, Fiquet, G, Galtier, E, Laso Garcia, A, Ginestet, H, Gizzi, L, Gleason, A, Goede, S, Gonzalez, J, Harmand, M, Hartley, N, Heighway, P, Hernandez-Gomez, C, Higginbotham, A, Höppner, H, Husband, R, Hutchinson, T, Hwang, H, Lazicki, A, Keen, D, Kim, J, Koester, P, Konopkova, Z, Kraus, D, Krygier, A, Labate, L, Lee, Y, Liermann, H, Mason, P, Masruri, M, Massani, B, Mcbride, E, Mcguire, C, Mchardy, J, Merkel, S, Morard, G, Nagler, B, Nakatsutsumi, M, Nguyen-Cong, K, Norton, A, Oleynik, I, Otzen, C, Ozaki, N, Pandolfi, S, Peake, D, Pelka, A, Pereira, K, Phillips, J, Prescher, C, Preston, T, Randolph, L, Ranjan, D, Ravasio, A, Redmer, R, Rips, J, Santamaria-Perez, D, Savage, D, Schoelmerich, M, Schwinkendorf, J, Smith, J, Sollier, A, Spear, J, Spindloe, C, Stevenson, M, Strohm, C, Suer, T, Tang, M, Toncian, M, Toncian, T, Tracy, S, Trapananti, A, Tschentscher, T, Tyldesley, M, Vennari, C, Vinci, T, Vogel, S, Volz, T, Vorberger, J, Walsh, J, Wark, J, Willman, J, Wollenweber, L, Zastrau, U, Brambrink, E, Appel, K, Mcmahon, M, Gorman, M. G., McGonegle, D., Smith, R. F., Singh, S., Jenkins, T., McWilliams, R. S., Albertazzi, B., Ali, S. J., Antonelli, L., Armstrong, M. R., Baehtz, C., Ball, O. B., Banerjee, S., Belonoshko, A. B., Benuzzi-Mounaix, A., Bolme, C. A., Bouffetier, V., Briggs, R., Buakor, K., Butcher, T., Di Dio Cafiso, S., Cerantola, V., Chantel, J., Di Cicco, A., Clarke, S., Coleman, A. L., Collier, J., Collins, G. W., Comley, A. J., Coppari, F., Cowan, T. E., Cristoforetti, G., Cynn, H., Descamps, A., Dorchies, F., Duff, M. J., Dwivedi, A., Edwards, C., Eggert, J. H., Errandonea, D., Fiquet, G., Galtier, E., Laso Garcia, A., Ginestet, H., Gizzi, L., Gleason, A., Goede, S., Gonzalez, J. M., Harmand, M., Hartley, N. J., Heighway, P. G., Hernandez-Gomez, C., Higginbotham, A., Höppner, H., Husband, R. J., Hutchinson, T. M., Hwang, H., Lazicki, A. E., Keen, D. A., Kim, J., Koester, P., Konopkova, Z., Kraus, D., Krygier, A., Labate, L., Lee, Y., Liermann, H. -P., Mason, P., Masruri, M., Massani, B., McBride, E. E., McGuire, C., McHardy, J. D., Merkel, S., Morard, G., Nagler, B., Nakatsutsumi, M., Nguyen-Cong, K., Norton, A. -M., Oleynik, I. I., Otzen, C., Ozaki, N., Pandolfi, S., Peake, D. J., Pelka, A., Pereira, K. A., Phillips, J. P., Prescher, C., Preston, T. R., Randolph, L., Ranjan, D., Ravasio, A., Redmer, R., Rips, J., Santamaria-Perez, D., Savage, D. J., Schoelmerich, M., Schwinkendorf, J. -P., Smith, J., Sollier, A., Spear, J., Spindloe, C., Stevenson, M., Strohm, C., Suer, T. -A., Tang, M., Toncian, M., Toncian, T., Tracy, S. J., Trapananti, A., Tschentscher, T., Tyldesley, M., Vennari, C. E., Vinci, T., Vogel, S. C., Volz, T. J., Vorberger, J., Walsh, J. P. S., Wark, J. S., Willman, J. T., Wollenweber, L., Zastrau, U., Brambrink, E., Appel, K., and McMahon, M. I.

Abstract

X-ray free electron laser (XFEL) sources coupled to high-power laser systems offer an avenue to study the structural dynamics of materials at extreme pressures and temperatures. The recent commissioning of the DiPOLE 100-X laser on the high energy density (HED) instrument at the European XFEL represents the state-of-the-art in combining x-ray diffraction with laser compression, allowing for compressed materials to be probed in unprecedented detail. Here, we report quantitative structural measurements of molten Sn compressed to 85(5) GPa and ∼ 3500 K. The capabilities of the HED instrument enable liquid density measurements with an uncertainty of ∼ 1 % at conditions which are extremely challenging to reach via static compression methods. We discuss best practices for conducting liquid diffraction dynamic compression experiments and the necessary intensity corrections which allow for accurate quantitative analysis. We also provide a polyimide ablation pressure vs input laser energy for the DiPOLE 100-X drive laser which will serve future users of the HED instrument.

Published
2024

9. The dual Ras-association domains of Drosophila Canoe have differential roles in linking cell junctions to the cytoskeleton during morphogenesis.

Author

McParland, Emily D., Gurley, Noah J., Wolfsberg, Leah R., Butcher, T. Amber, Bhattarai, Abhi, Jensen, Corbin C., Johnson, Ruth I., Slep, Kevin C., and Peifer, Mark

Subjects
ADHERENS junctions, CELL junctions, ACTOMYOSIN, DROSOPHILA, GUANOSINE triphosphatase
Abstract

During development cells must change shape and move without disrupting dynamic tissue architecture. This requires robust linkage of cell-cell adherens junctions to the force-generating actomyosin cytoskeleton. Drosophila Canoe and mammalian afadin play key roles in the regulation of such linkages. One central task for the field is defining mechanisms by which upstream inputs from Ras-family GTPases regulate Canoe and afadin. These proteins are unusual in sharing two tandem Ras-association (RA) domains - RA1 and RA2 - which when deleted virtually eliminate Canoe function. Work in vitro has suggested that RA1 and RA2 differ in GTPase affinity, but their individual functions in vivo remain unknown. Combining bioinformatic and biochemical approaches, we find that both RA1 and RA2 bind to active Rap1 with similar affinities, and that their conserved N-terminal extensions enhance binding. We created Drosophila canoe mutants to test RA1 and RA2 function in vivo. Despite their similar affinities for Rap1, RA1 and RA2 play strikingly different roles. Deleting RA1 virtually eliminates Canoe function, whereas mutants lacking RA2 are viable and fertile but have defects in junctional reinforcement in embryos and during pupal eye development. These data significantly expand our understanding of the regulation of adherens junction-cytoskeletal linkages. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

16. First person - Emily D. McParland and T. Amber Butcher.

Author

McParland, Emily D. and Butcher, T. Amber

Subjects
*MOLECULAR biology, *CAREER development, *FIRST-generation college students, *DEVELOPMENTAL biology, *SLAUGHTERING
Abstract

This article is an interview with the first authors of a paper published in the Journal of Cell Science. The authors, Emily D. McParland and T. Amber Butcher, conducted research on the Drosophila Canoe protein and its role in linking cell junctions to the cytoskeleton during embryonic development. They found that a specific domain of the Canoe protein, called the Dilute domain, is not essential for this linkage but supports the robustness of morphogenesis. The authors also discuss the challenges they faced during the project and their motivations for pursuing a career in science. [Extracted from the article]

Published
2024
Full Text
View/download PDF

17. Safety, feasibility, acceptability and preliminary effects of the Neurofenix platform for Rehabilitation via HOMe Based gaming exercise for the Upper-limb post Stroke (RHOMBUS): results of a feasibility intervention study

Author

Kilbride, C, Scott, DJM, Butcher, T, Norris, M, Warland, A, Anokye, N, Cassidy, E, Baker, K, Athanasiou, DA, Singla-Buxarrais, G, Nowicky, A, Ryan, J, Kilbride, C, Scott, DJM, Butcher, T, Norris, M, Warland, A, Anokye, N, Cassidy, E, Baker, K, Athanasiou, DA, Singla-Buxarrais, G, Nowicky, A, and Ryan, J

Abstract

OBJECTIVES: To investigate the safety, feasibility and acceptability of the Neurofenix platform for home-based rehabilitation of the upper limb (UL). DESIGN: A non-randomised intervention design with a parallel process evaluation. SETTING: Participants' homes, South-East England. PARTICIPANTS: Thirty adults (≥18 years), minimum 12-week poststroke, not receiving UL rehabilitation, scoring 9-25 on the Motricity Index (elbow and shoulder), with sufficient cognitive and communicative abilities to participate. INTERVENTIONS: Participants were trained to use the platform, followed by 1 week of graded game-play exposure and 6-week training, aiming for a minimum 45 min, 5 days/week. OUTCOMES: Safety was determined by assessing pain and poststroke fatigue at 8 and 12 weeks, and adverse events (AEs). Impairment, activity and participation outcomes were measured. Intervention feasibility was determined by the amount of specialist training and support required to complete the intervention, time and days spent training, and number of UL movements performed. Acceptability was assessed by a satisfaction questionnaire and semistructured interviews. RESULTS: Participants (14 women; mean (SD) age 60.0 (11.3) years) were a median of 4.9 years poststroke (minimum-maximum: 1-28 years). Twenty-seven participants completed the intervention. The odds of having shoulder pain were lower at 8 weeks (OR 0.45, 95% CI 0.24 to 0.83, p=0.010) and 12 weeks (OR 0.46, 95% CI 0.25 to 0.86, p=0.014) compared with baseline. Fugl-Meyer upper extremity, Motor Activity Log and passive range of movement improved. No other gains were recorded. Poststroke fatigue did not change. Thirty mild and short-term AEs and one serious (unrelated) AE were reported by 19 participants. Participants trained with the platform for a median of 17.4 hours over 7 weeks (minimum-maximum: 0.3-46.9 hours), equating to a median of 149 min per week. The median satisfaction score was 36 out of 40. CONCLUSION: The Neurofenix platform

Published
2022

18. Intrinsic energy flow in laser-excited 3d ferromagnets

Author

Zahn, D., Jakobs, F., Seiler, H., Butcher, T. A., Engel, D., (0000-0001-5926-9192) Vorberger, J., Atxitia, U., William Windsor, Y., Ernstorfer, R., Zahn, D., Jakobs, F., Seiler, H., Butcher, T. A., Engel, D., (0000-0001-5926-9192) Vorberger, J., Atxitia, U., William Windsor, Y., and Ernstorfer, R.

Abstract

Ultrafast magnetization dynamics are governed by energy flow between electronic, magnetic, and lattice degrees of freedom. A quantitative understanding of these dynamics must be based on a model that agrees with experimental results for all three subsystems. However, ultrafast dynamics of the lattice remain largely unexplored experimentally. Here, we combine femtosecond electron diffraction experiments of the lattice dynamics with energy-conserving atomistic spin dynamics (ASD) simulations and ab-initio calculations to study the intrinsic energy flow in the 3d ferromagnets cobalt (Co) and iron (Fe). The simulations yield a good description of experimental data, in particular an excellent description of our experimental results for the lattice dynamics. We find that the lattice dynamics are influenced significantly by the magnetization dynamics due to the energy cost of demagnetization. Our results highlight the role of the spin system as the dominant heat sink in the first hundreds of femtoseconds. Together with previous findings for nickel, our work demonstrates that energy-conserving ASD simulations provide a general and consistent description of the laser-induced dynamics in all three elemental 3d ferromagnets.

Published
2022

19. Data publication: Intrinsic energy flow in laser-excited 3d ferromagnets

Author

Zahn, D., Jakobs, F., Seiler, H., Butcher, T. A., Engel, D., (0000-0001-5926-9192) Vorberger, J., Atxitia, U., William Windsor, Y., Ernstorfer, R., Zahn, D., Jakobs, F., Seiler, H., Butcher, T. A., Engel, D., (0000-0001-5926-9192) Vorberger, J., Atxitia, U., William Windsor, Y., and Ernstorfer, R.

Abstract

DFT data concerning the electronic structure and electron-phonon coupling of Co and Fe. NOT the atomistic spin simulations. NO experimental data.

Published
2022

23. Lattice dynamics and ultrafast energy flow between electrons, spins, and phonons in a 3d ferromagnet

Author

Zahn, D., Jakobs, F., William Windsor, Y., Seiler, H., Vasileiadis, T., Butcher, T. A., Qi, Y., Engel, D., Atxitia, U., (0000-0001-5926-9192) Vorberger, J., Ernstorfer, R., Zahn, D., Jakobs, F., William Windsor, Y., Seiler, H., Vasileiadis, T., Butcher, T. A., Qi, Y., Engel, D., Atxitia, U., (0000-0001-5926-9192) Vorberger, J., and Ernstorfer, R.

Abstract

The ultrafast dynamics of magnetic order in a ferromagnet are governed by the interplay between electronic, magnetic and lattice degrees of freedom. In order to obtain a microscopic understanding of ultrafast demagnetization, information on the response of all three subsystems is required. A consistent description of demagnetization and microscopic energy flow, however, is still missing. Here, we combine a femtosecond electron diffraction study of the ultrafast lattice response of nickel to laser excitation with ab initio calculations of the electron-phonon interaction and energy conserving atomistic spin dynamics simulations. Our model is in agreement with the observed lattice dynamics and previously reported electron and magnetization dynamics. Our approach reveals that the spin system is the dominating heat sink in the initial few hundreds of femtoseconds and implies a transient non-thermal state of the spins. Our results provide a clear picture of the microscopic energy flow between electronic, magnetic and lattice degrees of freedom on ultrafast timescales and constitute a foundation for theoretical descriptions of demagnetization that are consistent with the dynamics of all three subsystems.

Published
2021

30. Data for: Lattice dynamics and ultrafast energy flow between electrons, spins, and phonons in a 3d ferromagnet

Author

Zahn, D., Jakobs, F., William Windsor, Y., Seiler, H., Vasileiadis, T., Butcher, T. A., Qi, Y., Engel, D., Atxitia, U., Vorberger, J., and Ernstorfer, R.

Subjects
electron beam, relaxation, Physics::Optics, magnetization, phonon, spin, DFT, femtosecond, laser
Abstract

The ultrafast dynamics of magnetic order in a ferromagnet are governed by the interplay between electronic, magnetic and lattice degrees of freedom. In order to obtain a microscopic understanding of ultrafast demagnetization, information on the response of all three subsystems is required. A consistent description of demagnetization and microscopic energy flow, however, is still missing. Here, we combine a femtosecond electron diffraction study of the ultrafast lattice response of nickel to laser excitation with ab initio calculations of the electron-phonon interaction and energy conserving atomistic spin dynamics simulations. Our model is in agreement with the observed lattice dynamics and previously reported electron and magnetization dynamics. Our approach reveals that the spin system is the dominating heat sink in the initial few hundreds of femtoseconds and implies a transient non-thermal state of the spins. Our results provide a clear picture of the microscopic energy flow between electronic, magnetic and lattice degrees of freedom on ultrafast timescales and constitute a foundation for theoretical descriptions of demagnetization that are consistent with the dynamics of all three subsystems.

Published
2020
Full Text
View/download PDF

31. Energy relaxation and electron phonon coupling in laser heated solids

Author

Vorberger, J. and Butcher, T. A.

Subjects
warm dense matter, energy relaxation, temperature relaxation, electron-phonon coupling, laser heating
Abstract

density functional theory based description of electron phonon coupling for energy relaxation in laser heated solids

Published
2020

34. Fermi surface investigation of the semimetal TaAs2

Author

Butcher, T., Hornung, J., Förster, T., Uhlarz, M., Klotz, J., Sheikin, I., Wosnitza, J., and Kaczorowski, D.

Subjects
Condensed Matter::Superconductivity, Condensed Matter::Strongly Correlated Electrons
Abstract

The transversal magnetoresistance associated with the semimetal TaAs2 shows a parabolic field dependence that rises unrestrictedly to 2800 at 14 T and 1.8 K. Here, we report the results of a comprehensive quantum-oscillation study. Angular-dependent de Haas–van Alphen (dHvA) data were obtained with the method of cantilever-torque magnetometry. These were compared with the results of density-functional theory calculations, which predict a Fermi surface with two kinds of electron pockets, as well as two types of hole pockets. Only the electron pockets could be xperimentally verified, whereas no evidence for the hole pockets is present in the measured dHvA frequencies.

Published
2019

35. Heat transfer surfaces in domestic, oilfired heating boilers

Author

Butcher, T., Celebi, Y., Litzke, W., and Lee, S.W.

Subjects
Boilers -- Energy use, Business, Petroleum, energy and mining industries
Abstract

Issues concerning the fouling of the convective heat exchanger surfaces of small, oilfired domestic heating boilers are discussed. The use of lower sulphur content fuels in domestic boilers will bring reduced fouling rates.

Published
2000

36. Performance comparison of Yb:YAG ceramics and crystal gain material in a large-area, high-energy, high average–power diode-pumped laser

Author

Divoky, M., primary, Pilar, J., additional, Hanus, M., additional, Navratil, P., additional, Sawicka-Chyla, M., additional, De Vido, M., additional, Phillips, P. J., additional, Ertel, K., additional, Butcher, T., additional, Fibrich, M., additional, Green, J. T., additional, Koselja, M., additional, Preclikova, J., additional, Kubat, J., additional, Houzvicka, J., additional, Rus, B., additional, Collier, J., additional, Lucianetti, A., additional, and Mocek, T., additional

Published
2020
Full Text
View/download PDF

50. The convergence of emerging groups via Web 2.0 social networking sites

Author

Loureiro-Koechlin, C and Butcher, T

Subjects
Internet research
Abstract

In the 1980s and ‘90s online communities were said to have freed us from geographical and time constraints. Yet they were defined by the virtual space used to host people’s interactions. Online communities were artificially constructed each with a distinctive theme agreed by their designers. Membership was granted by subscription. Users interested in the community’s theme joined to search for content and meet people with similar interests. In new Web 2.0 environments such as social networking sites (SNS), users sign up to the tool but not to the networks. These sites are not owned by one group of people but by many with different interests and purposes. Social networks are built by the links users create between them and strengthened by meaningful participation. Online communities can emerge from these socializations when groups of people empathize and discover similarities between them. Membership and boundaries of these communities are not defined by the space or the account but by people and participation. In this paper we present findings from ethnographic research of an online community that has emerged from converging social networks on Twitter. Face-to-face semi-structured interview data are triangulated with the results from an online questionnaire via Twitter and analysis of community discussion threads using hashtags to validate a conceptual framework of how communities form and grow via SNS. In this research we explore the different layers of use (one-to-one relationships, Twitter networks and online community), the roles individuals adopt in this emerging community, and their strategies for managing their co-existence with other networks in the same space. Furthermore we investigate how this online community has transitioned from its interest-driven origins to supporting friendship-driven interactions. We offer a contribution to knowledge in terms of providing a clearer definition of how contemporary communities are enabled by SNS, and how those communities overlap.

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results