Markus Reiner, Israeli engineer and educator (b. 1886)
Markus Reiner (Hebrew: מרכוס ריינר), born on January 5, 1886, in Czernowitz, then part of the Austro-Hungarian Empire, and who passed away on April 25, 1976, was a distinguished Israeli scientist widely regarded as a pivotal and foundational figure in the nascent field of rheology. His profound theoretical contributions and pioneering spirit helped shape the understanding of how matter flows and deforms, leaving an indelible mark on both academia and industry.
A Journey to Scientific Prominence
Reiner's early life saw him pursue civil engineering, graduating from the Technische Hochschule in Vienna. After serving in the First World War, he immigrated to the British Mandate of Palestine in 1922, a move that would profoundly influence his career and identity as an Israeli scientist. He initially applied his engineering expertise within the Public Works Department, contributing to the development of the region's infrastructure. However, his academic calling soon led him to the Technion – Israel Institute of Technology in Haifa, where he joined the faculty in 1931. It was at Technion that Reiner would dedicate the majority of his prolific career, rising to become a revered professor and a beacon of scientific inquiry.
The Father of Rheology: Groundbreaking Contributions
Markus Reiner, alongside American chemist Eugene C. Bingham, is often credited with coining the term "rheology" in 1929, deriving it from the Greek words "rheos" (flow) and "logos" (study). This marked the formal establishment of a new scientific discipline dedicated to understanding the flow and deformation of materials under stress, bridging physics, engineering, and chemistry.
- The Deborah Number: Perhaps one of his most famous contributions is the introduction of the dimensionless Deborah number. This concept, humorously named after a passage in the biblical song of Deborah ("The mountains flowed before the Lord"), quantifies the fluidity of a material relative to the observation time. A high Deborah number indicates solid-like behavior over the observation time, while a low number suggests fluid-like behavior. It's a fundamental tool in characterizing material response.
- Reiner-Rivlin Fluids: Collaborating with Ronald Rivlin, Reiner developed the theory of Reiner-Rivlin fluids, a class of non-Newtonian fluids whose constitutive equations describe complex flow behaviors not covered by simpler models. This work was crucial for understanding materials like polymers, slurries, and biological fluids.
- Reiner-Riwlin Equation: He also formulated the Reiner-Riwlin equation, which describes the flow of certain non-Newtonian fluids in specific geometries, such as between rotating concentric cylinders.
- Authored Influential Texts: Reiner was a prolific author, publishing several seminal books that became standard references in the field, including "Deformation and Flow" (1949), "Twelve Lectures on Theoretical Rheology" (1961), and "Rheology" (1958), which helped disseminate the principles of rheology to a global audience.
- Organizational Leadership: Beyond his theoretical work, Reiner played a crucial role in establishing the international rheological community, including involvement in the International Congress on Rheology, fostering collaboration and the exchange of ideas among researchers worldwide.
His work provided the theoretical underpinnings for countless practical applications, from designing more efficient industrial processes in plastics, food, and cosmetics manufacturing, to understanding biological processes and geological phenomena.
Enduring Legacy
Markus Reiner's legacy is immense. He not only helped define and name a new scientific discipline but also provided many of its fundamental theoretical tools and concepts. His dedication to research and teaching at the Technion cemented Israel's place on the global map for rheological studies. He is remembered not only for his intellectual rigor but also for his engaging personality and ability to convey complex ideas with clarity and wit, making him a true pioneer whose influence continues to resonate in materials science and engineering today.
Frequently Asked Questions (FAQs)
- Who was Markus Reiner?
- Markus Reiner was a distinguished Israeli scientist, born in 1886 and died in 1976, renowned as one of the founding fathers and leading figures in the field of rheology, the study of the flow and deformation of matter.
- What is rheology?
- Rheology is a branch of physics that studies the flow (liquids) and deformation (solids) of matter. It applies to materials that exhibit complex mechanical properties, such as polymers, gels, biological fluids, and even some geological formations, bridging fluid mechanics and solid mechanics.
- What is the significance of the Deborah number?
- The Deborah number, introduced by Markus Reiner, is a crucial dimensionless quantity in rheology. It expresses the ratio of a material's relaxation time (how long it takes for a material to respond to stress) to the characteristic time of the experiment or observation. It helps classify materials as more fluid-like or solid-like under specific conditions.
- What were some of Markus Reiner's major contributions to science?
- Reiner's major contributions include coining the term "rheology," introducing the Deborah number, developing the theory of Reiner-Rivlin fluids and the Reiner-Riwlin equation for non-Newtonian flow, and authoring several foundational textbooks that shaped the field. He also played a key role in establishing the international rheological community.
- Where did Markus Reiner conduct his primary research?
- After immigrating to Palestine, Markus Reiner primarily conducted his research and taught as a professor at the Technion – Israel Institute of Technology in Haifa, where he spent the majority of his illustrious career.