In Memoriam: David Vernon Boger (1939–2025)

It is with profound grief that we announce this loss to our global rheology community. Professor Boger was not only one of the world’s most distinguished rheologists but also a founding pillar of the Australian Society of Rheology and a champion of international collaboration within our field.

Professor Boger’s impact on rheology extends far beyond his groundbreaking research, including the development of the constant-viscosity elastic fluids that bear his name - “Boger fluids.” As the 1994 recipient of our Society’s highest honor, the ASR Medallion, he fundamentally advanced our understanding of non-Newtonian fluid mechanics and viscoelastic flow behavior, influencing countless researchers worldwide. He was equally passionate about applying rheological science to solve real-world problems, particularly in environmental applications and the minerals industry, where his work enabled the alumina industry to use 50% less water and produce solid waste rather than liquid waste, leading to much more environmentally acceptable processes.

Professor Boger played a pivotal role in strengthening international bonds within the rheology community. His leader- ship was particularly evident in devel- oping the close relationship between the Australian Society of Rheology and international partner societies. On behalf of the Australian Society of Rheology, we especially acknowledge the extraordinary partnership that Professor Boger, together with Professor Jae Chun Hyun, forged between our societies. This vision- ary collaboration began with the inaugural Australia-Korea Rheology Conference (AKRC) held in Sydney in 2001, followed by the Korean-Australian Rheology Conference in Gyeongju in 2003. These conferences established a tradition of scientific exchange and friendship between our nations that continues to flourish today, a lasting testament to Professor Boger’s commitment to international cooperation and his deep respect for Korean rheological research.

Born on November 13, 1939, in Kutztown, Pennsylvania, Professor Boger graduated from Bucknell University with a Bachelor’s degree in Chemical Engineering and obtained his PhD at the University of Illinois, Urbana- Champaign in 1965. He joined Monash University as a Lecturer soon after com- pleting his PhD, beginning his journey in rheology, a field that was completely new to him at the time. He later moved to the University of Melbourne in 1982 as Professor in the Department of Chemical and Biomolecular Engineering, where he served in various leadership roles including Head of Department and Deputy Dean, before returning to Monash University as Engineering Professor in 2010 until his retirement in 2015.

As a founding member and tireless advocate for the Australian Society of Rheology, Professor Boger understood that science knows no borders. He served as the Australian Delegate to the International Committee on Rheology for many years and was instrumental in establishing collaborative relationships with rheology societies worldwide. His scientific expertise was widely sought after; he consulted for over 90 companies worldwide and served as an expert witness in several international court cases.

His commitment to mentoring young researchers and sharing knowledge across borders has left an indelible mark on our field. Throughout his distinguished career, Professor Boger received numerous accolades, including: Companion of the Order of Australia (AC, 2024), Member of the US National Academy of Engineering (2017), Fellow of the Royal Society (FRS, 2007), Prime Minister’s Prize for Science (Australia, 2005), Gold Medal of the British Society of Rheology (2004), Centenary Medal of the Commonwealth of Australia (2003), Flinders Medal of the Australian Academy of Science (2000), Walter Ahlstroem Environmental Prize of the Finnish Academy of Technology (1995), ASR Medallion (1994), Fellow of the Australian Academy of Science (FAA, 1993), Fellow of the Australian Academy of Technological Sciences and Engineering (FTSE)

As we mourn the loss of Professor Boger, the Australian Society of Rheology also celebrates his remarkable legacy. Those who knew him remember him as a warm, generous, and kind colleague who was unsparing with his time and an inspiring mentor. The international collaborations he helped establish, the scientific advances he made, and the countless researchers he inspired will continue to benefit our com- munity for generations to come.

The Australian Society of Rheology invites colleagues who worked with Professor Boger or benefited from his mentorship to share their memories and reflections on his impact on the field. We are committed to continuing the spirit of international collaboration that he so pas- sionately championed.
With deepest condolences and warm regards to our colleagues worldwide, Australian Society of Rheology

Born in Athens on June 13, 1928, Professor Acrivos emigrated to the United States to pursue studies in chemical engineering. He earned his bachelor’s degree from Syracuse University in 1950 and continued his graduate studies at the University of Minnesota, where he received his master’s degree in 1951 and his Ph.D. in 1954. His academic career began at the University of California, Berkeley, in 1954, where he was appointed Assistant Professor and promoted to Professor in 1959. In 1962, he moved to Stanford University, where he played a pivotal role in the development of the chemical engineering program and served as department chair from 1972 to 1975. Professor Acrivos left Stanford in 1988, when he accepted the position of Albert Einstein Professor of Science and Engineering at the City College of New York. He was also appointed the Director of the Benjamin Levich Institute for Physico-Chemical Hydrodynamics at City College until his retirement in 2001. His research contributions focused on studying the properties of suspensions, emulsions, and fiber-filled materials, significantly influencing the understanding of their microstructure and microrheology. His work, in collaboration with Frankel and Leighton, on concentrated suspensions and shear diffusion, remains a cornerstone of modern rheology. Furthermore, his mentorship was crucial to the development of many distinguished scientists, such as J.D. Goddard, L.G. Leal, D. Barthes-Biesel, W.B. Russel, J.F. Brady, D. Leighton, and E.S.G. Shaqfeh, and G. G. Fuller, many of whom are or were at the forefront of rheology.

Professor Acrivos was honored with numerous prestigious awards and distinctions, including the National Medal of Science (2001), recognizing his contributions to fluid mechanics and chemical engineering, the Fluid Dynamics Prize from the American Physical Society (1991), the Bingham Medal from the Society of Rheology (1994) and the G.I. Taylor Medal from the Society of Engineering Science (1988). In addition to these prestigious accolades, two significant awards have been established in his honor that include the Andreas Acrivos Award for Professional Progress in Chemical Engineering by the American Institute of Chemical Engineers (AIChE), recognizing outstanding professional achievements in the field of chemical engineering and the Andreas Acrivos Dissertation Award, presented by the American Physical Society, to recognize outstanding dissertations in fluid dynamics.He was a member of the National Academy of Sciences, the National Academy of Engineering, and the American Academy of Arts and Sciences. In 2001, the Hellenic Society of Rheology recognized him as an honorary member, honoring his long-standing and significant contribution to the field of rheology.

Professor Acrivos is survived by his wife Juana, his sister, Acrivy Stavropoulos, niece Maria and nephew Andreas in Athens, sister-in-law Lily Crespo Vivo’ and family Armando and Antonieta Crespo their children, grandchildren and godchildren. He is also remembered by a host of graduate students, postdocs, fellow faculty and co-workers that benefited over so many years from his wisdom and mentorship.