Nathan Mendelsohn is not a widely recognized public figure or term as of my last update in October 2023. It is possible he could be a lesser-known individual, a private citizen, or a fictional character from a book, film, or other forms of media.

Roland Richardson is an artist renowned for his vibrant depictions of Caribbean landscapes, particularly those of St. Martin, where he is from. His work often incorporates intense colors and expressive brushwork, capturing the beauty of nature and the essence of island life. Richardson's art reflects his deep connection to his surroundings and has garnered recognition both locally and internationally. He works with various mediums, including oil and watercolor, and often portrays the flora, fauna, and cultural elements of the region.

Samuel Beatty was a Canadian mathematician known for his contributions to the field of mathematics, particularly in number theory and analysis. He is perhaps best known for the Beatty sequences, which are two sequences of numbers that are formed by taking the ceiling of multiples of two irrational numbers. The sequences have interesting properties and applications in various areas of mathematics. Beatty's work primarily involved exploring the properties of these sequences and their relationships to other mathematical concepts.

Victor Ivrii is a notable mathematician known for his contributions to several areas of mathematics, particularly in analysis and partial differential equations. He has worked on topics such as microlocal analysis, pseudodifferential operators, and the theory of elliptic operators. Ivrii has also been involved in mathematical education and research, and he has authored a number of papers and texts in his field.

Renfrey Potts is a notable figure in the field of mathematics, particularly known for his contributions to the study of geometric topology and algebraic topology. He has made significant advancements in understanding the interplay between these areas, and he is recognized for his work on topics such as knot theory and the properties of manifolds.

Mark Ellingham is a British travel publisher and the founder of the renowned travel guide company, *Rough Guides*. Established in the 1980s, *Rough Guides* is known for its comprehensive and insightful travel publications, which cover various destinations around the world. Ellingham has been influential in shaping the travel publishing industry, promoting a more adventurous and independent approach to travel. The guides are recognized for their detailed information, practical tips, and emphasis on cultural immersion.

Michael Scott Jacobson is a notable figure in the fields of public health and nutrition. He is often recognized for his contributions to the understanding of dietary influences on health and has been involved in various academic and research pursuits. Jacobson is also known for his advocacy on issues related to food policy, particularly in the context of improving public health outcomes through better nutrition and dietary practices.

Narsingh Deo is a historical figure from India, typically associated with the region of Odisha. He is often recognized as a significant ruler of the Ganga dynasty during the medieval period. The Ganga dynasty was known for its contributions to art, architecture, and culture, particularly in the temple town of Puri, which is famous for the Jagannath Temple.

Paul Kelly is a mathematician known for his contributions to various areas of mathematics, particularly in the field of graph theory, combinatorics, and mathematical logic. He has published research papers and is known for his work on topics such as combinatorial designs and algorithms. In addition to his academic work, Paul Kelly may also be involved in teaching and mentoring students in mathematics, contributing to the development of the mathematical community. His influence may extend through publications, conferences, and collaborations with other mathematicians.

Philippe Flajolet (1941–2011) was a prominent French mathematician and computer scientist known for his contributions to combinatorics, algorithm analysis, and the theory of algorithms. He is particularly recognized for his work in analytic combinatorics, a field that uses generating functions and complex analysis to study combinatorial structures. Flajolet co-authored several influential papers and books, notably "Analytic Combinatorics," which he wrote with Robert Sedgewick.

Ping Zhang is a mathematician known for his contributions to graph theory, a branch of mathematics that studies graphs, which are mathematical structures used to model pairwise relationships between objects. His research often focuses on topics such as graph coloring, extremal graph theory, and the properties of specific types of graphs. Zhang has published various papers and has been involved in advancing the understanding of different aspects of graph theory.

As of my last update in October 2021, there isn't any widely known public figure, event, or concept specifically called "Regina Tyshkevich." It's possible that this name could refer to a private individual or a less prominent figure not covered in mainstream sources.

Robert Frucht is a name that could refer to various individuals, but without additional context, it's difficult to determine exactly who you are asking about. If you are referring to a specific person, such as an author, scientist, or someone in a particular field, please provide more details. Otherwise, it may be possible that the name is not widely recognized in popular or academic circles.

S. A. Choudum does not appear to be a widely recognized term, name, or concept based on my training data up to October 2023. It is possible that it could refer to a specific person, organization, or topic that is less well-known or not widely documented in major sources.

V. J. Havel may refer to Václav Havel, a prominent Czech playwright, dissident, and politician who served as the last president of Czechoslovakia from 1989 to 1992 and the first president of the Czech Republic from 1993 to 2003. He was a leading figure in the Velvet Revolution, which peacefully ended communist rule in Czechoslovakia.

Vance Faber is not a widely recognized term or figure, and it could refer to various subjects depending on the context. It might refer to a person, a brand, or something else entirely.

Bottled gas refers to various types of gases that are stored under pressure in containers, typically cylinders or bottles. It is commonly used for a variety of applications, including heating, cooking, and fuel for vehicles. The most common types of bottled gas include: 1. **Liquefied Petroleum Gas (LPG)**: A mixture of propane and butane, LPG is widely used for home heating, cooking, and hot water systems. It is also used in certain vehicles as an alternative fuel.

A Fisher-Porter tube is a type of laboratory apparatus used to measure the concentration of gases, specifically oxygen, in a gas mixture. It operates on the principle of gas absorption, where a gas flows through a liquid and allows for the measurement of the gas's partial pressure. The device utilizes a liquid, often containing a chemical reagent that reacts with oxygen, to help determine the concentration of oxygen in the gas stream.

A hydrogen tank is a storage container used to hold hydrogen gas, typically under high pressure. These tanks are designed to safely store and transport hydrogen for various applications, including fuel cell vehicles, industrial processes, and energy storage systems. There are several key features and characteristics of hydrogen tanks: 1. **Material**: Hydrogen tanks are often made from materials that can withstand high pressures, such as aluminum or composite materials (e.g., carbon fiber reinforced polymers). These materials help reduce weight while maintaining strength.

Valve Corporation is a video game development and digital distribution company founded in 1996 by Gabe Newell and Mike Harrington. It is known for creating some of the most popular and influential video games in the industry, including the "Half-Life" series, "Portal," "Team Fortress," and "Dota 2." Valve also developed the Source game engine, which powered many of its titles.