This document summarizes the history and evolution of the transient hot-wire (THW) technique for measuring thermal conductivity from 1780 to today. It traces the key developments from the early experiments measuring gas conductivity in the 1780s, through the introduction of heated wire experiments in the 1840s-1860s, to the first use of the horizontal hot-wire apparatus in 1888. It then discusses improvements like the vertical wire setup in 1917 and the first transient hot-wire experiments in 1931, which employed a fine wire subjected to a step change in heat to measure conductivity of solids, powders and liquids. The document examines the work of important figures like Priestley, Rumford, Leslie, Grove, Magnus, Maxwell
This document provides an outline of the history of electromagnetism from ancient times to around 1800. It describes key discoveries and experiments, including Gilbert attributing electrification to the removal of a fluid, von Guericke building the first electrostatic generator, Franklin's kite experiment proving lightning is a spark, and Coulomb demonstrating the inverse square law of electrostatics using a torsion balance. The mathematical theories of figures like Laplace, Poisson, and Gauss helped formalize the understanding of electrostatics.
This document provides an introduction and history of thermoacoustics. It discusses how thermoacoustics combines acoustics and thermodynamics to move heat using sound waves. The document outlines some of the early experiments in thermoacoustics dating back to the 18th century. It then discusses the development of quantitative thermoacoustic theory in the 19th and 20th centuries. Specifically, it discusses Rott's breakthroughs in the 1960s that allowed for the design of thermoacoustic engines and refrigerators. The document provides context on current research focused on improving efficiency and power density of thermoacoustic devices. It describes the objectives of creating knowledge about thermoacoustic refrigeration at the University
This document summarizes the lives and accomplishments of several scientists throughout history. It notes that Archimedes invented the pulley, screw pump, and studied hydrostatics and levers. Copernicus developed the first full heliocentric theory of the universe. Galileo made improvements to the telescope and discovered that mass does not affect descent rate. Leeuwenhoek invented the microscope and was the first to study cells. Newton originated the laws of motion and universal law of gravitation. Pasteur developed pasteurization and vaccines. Halley discovered Halley's Comet. Marconi invented radio. Tesla developed alternating current power systems. Einstein developed the theory of relativity and equation E=mc2. Jane Goodall studied chimpan
This document provides an overview of teaching kinetic theory and the behavior of gases. It outlines learning outcomes, common student misconceptions, teaching challenges, and evidence that supports the atomic model of matter. Examples are given to illustrate gas properties, laws, and the historical development of the kinetic theory of gases. Suggestions for demonstrations and simulations to teach these concepts in an engaging, hands-on manner are also provided.
This document discusses thermoacoustics, which uses thermal energy to generate or amplify sound waves. It describes how sound waves can be amplified through heat and used to drive a piston. The key components of thermoacoustic systems are the driver, resonator, stack, and heat exchangers. The resonator contains gas that undergoes compression and cooling from the sound waves. The stack facilitates heat transfer through many small parallel channels. Thermoacoustic systems can be used for refrigeration and have benefits like being environmentally friendly.
This document provides an outline of the history of electromagnetism from ancient times to around 1800. It describes key discoveries and experiments, including Gilbert attributing electrification to the removal of a fluid, von Guericke building the first electrostatic generator, Franklin's kite experiment proving lightning is a spark, and Coulomb demonstrating the inverse square law of electrostatics using a torsion balance. The mathematical theories of figures like Laplace, Poisson, and Gauss helped formalize the understanding of electrostatics.
This document provides an introduction and history of thermoacoustics. It discusses how thermoacoustics combines acoustics and thermodynamics to move heat using sound waves. The document outlines some of the early experiments in thermoacoustics dating back to the 18th century. It then discusses the development of quantitative thermoacoustic theory in the 19th and 20th centuries. Specifically, it discusses Rott's breakthroughs in the 1960s that allowed for the design of thermoacoustic engines and refrigerators. The document provides context on current research focused on improving efficiency and power density of thermoacoustic devices. It describes the objectives of creating knowledge about thermoacoustic refrigeration at the University
This document summarizes the lives and accomplishments of several scientists throughout history. It notes that Archimedes invented the pulley, screw pump, and studied hydrostatics and levers. Copernicus developed the first full heliocentric theory of the universe. Galileo made improvements to the telescope and discovered that mass does not affect descent rate. Leeuwenhoek invented the microscope and was the first to study cells. Newton originated the laws of motion and universal law of gravitation. Pasteur developed pasteurization and vaccines. Halley discovered Halley's Comet. Marconi invented radio. Tesla developed alternating current power systems. Einstein developed the theory of relativity and equation E=mc2. Jane Goodall studied chimpan
This document provides an overview of teaching kinetic theory and the behavior of gases. It outlines learning outcomes, common student misconceptions, teaching challenges, and evidence that supports the atomic model of matter. Examples are given to illustrate gas properties, laws, and the historical development of the kinetic theory of gases. Suggestions for demonstrations and simulations to teach these concepts in an engaging, hands-on manner are also provided.
This document discusses thermoacoustics, which uses thermal energy to generate or amplify sound waves. It describes how sound waves can be amplified through heat and used to drive a piston. The key components of thermoacoustic systems are the driver, resonator, stack, and heat exchangers. The resonator contains gas that undergoes compression and cooling from the sound waves. The stack facilitates heat transfer through many small parallel channels. Thermoacoustic systems can be used for refrigeration and have benefits like being environmentally friendly.
Isaac Newton was an English scientist who made seminal contributions to physics, including formulating the laws of motion and universal gravitation. He discovered that white light comprises a spectrum of colors and that gravity explains the motions of celestial bodies. Newton published his theories and laws in Philosophiae Naturalis Principia Mathematica. He served as a professor of mathematics at the University of Cambridge and was considered the greatest genius of his time.
This document summarizes the rules and questions from the UTSUK '14 quiz competition. The rules state that questions can be answered by the team asked or opposing teams who "pounce". Pounces must be answered within 30 seconds. Correct answers receive 10 points, wrong answers receive -5 points. The questions cover topics in meteorology, astronomy, history of science and technology, chemistry, and geology. Sample questions ask about rain shadows, sunspots, the limelight, vanishing spray, eye color determination, columnar basalt, and the synthesis of paracetamol. The document provides a high-level overview of the format and content of the quiz competition.
The group presentation provides biographical information about Albert Einstein and summarizes his theory of relativity and equation E=MC2. It discusses Einstein's life and career, including being born in Germany but later having to leave due to his Jewish heritage. The presentation also covers the social, economic, political, and mathematical contexts surrounding Einstein's work, and provides an example using the principle of conservation of energy to illustrate his equation equating energy and mass.
This document is a presentation on entropy that contains sections on the history, concept, definition, expressions, classifications, applications, and conclusions of entropy. It begins with introducing entropy and its origins from Rudolf Clausius in 1854. It then discusses entropy as a measure of disorder and the number of microscopic states a system can be in. The document defines entropy using Boltzmann's constant and covers the classification of entropy including thermodynamic, statistical, and quantum entropy. It concludes that entropy is a measure of disorder that increases over time according to the second law of thermodynamics.
The document discusses several experiments from 1905-1925 that provided evidence that challenged classical physics and led to the development of quantum theory, including:
- Heat capacity experiments showing heat capacity decreases with temperature, contradicting classical physics (1905-1906)
- Photoelectric effect experiments showing electrons ejected by frequency-dependent photons, not intensity (1905)
- Atomic spectroscopy experiments showing atoms absorb/emit only discrete frequencies (1885, early 1900s)
This document provides biographical information on several scientists from history:
- David Brewster - A Scottish physicist known for contributions to optics and inventions like the kaleidoscope.
- Abraham Brook - An English bookseller who also conducted experiments in electricity and vacuum technology.
- František Josef Gerstner - A Bohemian physicist and engineer who helped establish technical schools and studied applied mechanics.
- Johannes Gessner - A Swiss mathematician, physicist and physician seen as the founder of a natural science society in Zurich.
- Johann Baptiste Horvath - A Hungarian Jesuit professor known for authoring physics and other textbooks that were widely distributed.
- Pierre Lemonnier -
The document discusses the physics of galaxy cluster plasmas, including convection processes like the Magnetothermal Instability (MTI) and Heat Flux-Driven Buoyancy Instability (HBI) that are driven by anisotropic thermal conduction. While clusters appear to be in global thermal equilibrium, local thermal instability can occur where the cooling time divided by the free-fall time is less than 10, allowing multiphase gas structures to form through thermal instability. Cosmological simulations show that heating from processes like AGN can self-regulate clusters to maintain a minimum cooling-to-free-fall time ratio of around 10 and minimum central entropy of 10-30 keV cm2, consistent with observations.
Here is a summary of the key points about carbon's atomic structure based on the information provided:
- Carbon has 6 protons and 6 neutrons in its nucleus.
- Its mass number is 12 and atomic number is 6.
- The number of protons equals the atomic number of 6.
- The number of neutrons is the mass number (12) minus the atomic number (6), which is 6.
- The number of electrons orbiting the nucleus equals the number of protons, which is 6.
So in summary, carbon has 6 protons and 6 neutrons in its nucleus, and 6 electrons orbiting the nucleus.
The document discusses the history of the atomic theory from ancient philosophers to modern scientists. It describes early thinkers like Thales who discovered static electricity but did not connect it to atoms. Democritus in 400 BC proposed that all matter is made of indivisible atoms that differ in shape and size. In the 1800s, Dalton, Dobereiner, and Berzelius conducted experiments that provided evidence for the atomic theory. Mendeleev organized the known elements into the first periodic table in 1869. In the early 1900s, Thomson discovered the electron, Rutherford proposed the nuclear model of the atom, and Moseley ordered the elements by atomic number, correcting Mendeleev's table.
This document provides biographical details about Albert Einstein's life and career. It describes key events such as his education in Germany and Switzerland, early work at the Swiss Patent Office, "miracle year" of 1905 when he published four groundbreaking papers on light quanta, photoelectric effect, Brownian motion, and special relativity, development of his general theory of relativity between 1907-1915, and verification of his theory through observations of star positions during a solar eclipse in 1919. The document establishes Einstein as a revolutionary physicist who changed our understanding of space, time, light, and gravity through his scientific theories.
Democritus first proposed the existence of atoms in 460 BC, though the atomic theory was not widely accepted until John Dalton proposed it in 1803 based on the laws of multiple and constant proportions. The discovery of subatomic particles like the electron by J.J. Thomson in 1897 and proton by Rutherford in 1911 led to proposed atomic models like the plum pudding model and nuclear atom. Defining the mass and charge of these particles along with isotopes observed by Francis Aston and the neutron discovered by James Chadwick in 1932 completed the basic components of the modern atomic theory.
The document provides a timeline of important discoveries and developments in the understanding of the atom from ancient Greek philosophers Democritus and Aristotle up to the early 20th century. It describes key contributions such as Democritus' idea that all matter is made of indivisible atoms, Dalton introducing atomic theory in 1802, Mendeleev organizing the periodic table in 1869, Thomson discovering the electron in 1897, Rutherford proposing the nuclear model of the atom in 1911, and Moseley ordering the elements by atomic number in 1913.
The document discusses the contributions of several famous scientists to the field of physics, including C.V. Raman who discovered the Raman effect and won the 1930 Nobel Prize, Albert Einstein who developed the theories of special and general relativity and won the 1921 Nobel Prize, Sir Isaac Newton who formulated the laws of motion and universal gravitation, and Archimedes who invented machines and formulated principles of hydrostatics and levers.
This document discusses heat transfer and thermodynamics. It begins by defining heat transfer as the science of calculating the rate at which heat flows within or between mediums. Thermodynamics deals with energy transfers that cause systems to change equilibrium states. The document then discusses the different methods of heat transfer: conduction, convection, and radiation. It provides examples and explanations of each type. The remainder of the document focuses on conduction and convection in more detail, explaining concepts like thermal conductivity, thermal resistance, boundary layers, and free and forced convection.
Sir Isaac Newton was an influential English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian. In his Philosophiae Naturalis Principia Mathematica, published in 1687, he described universal gravitation and the three laws of motion, laying the groundwork for classical mechanics. Newton showed that terrestrial and celestial motions are governed by the same laws and helped advance the scientific revolution. He also made important contributions to optics, mathematics, and astronomy.
Geologists used new evidence from physics, including radioactive dating and heat sources within the Earth, to show that the Earth was older than physicists had estimated based on cooling models alone. Lord Kelvin had estimated the Earth's age as between 20-40 million years based on cooling rates, but radioactive elements provided additional heat sources and evidence that the Earth was at least 1.6 billion years old. By considering multiple heat sources and dating methods, geologists and physicists reconciled differing age estimates to establish that the Earth was over 3 billion years old.
Geologists used various dating methodologies involving ocean chemistry, erosion rates, and radiometric dating to determine that the Earth is billions of years old, contradicting earlier estimates by physicists like Kelvin of only millions of years based on cooling models. The discovery of radioactivity provided a major new heat source inside the Earth and revealed processes like radioactive decay that allowed for much older dating of rocks and minerals, establishing the age of the Earth to be over 4 billion years.
This document provides an overview of Aristotle and his works. It discusses that Aristotle was a student of Plato and established his own school called the Lyceum. Aristotle focused on empirical knowledge gained from observation and experience, in contrast to Plato who believed true knowledge came from contemplation. Aristotle made detailed classifications of phenomena and employed logic and reasoning. However, his conclusions were sometimes flawed due to incorrect generalizations. The document examines Aristotle's theories of causation, motion, and his cosmological model of the spherical earth surrounded by nested spheres carrying the sun, moon, and planets in uniform circular motion.
Aristotle was a student of Plato who established his own school called the Lyceum in Athens. He tutored Alexander the Great for several years. Aristotle's works were based on careful observation and classification of the natural world. He developed logic and identified four causes to explain things: material, formal, efficient, and final. Aristotle built a complete system to explain the world, dividing it into a changing sublunary region and a fixed heavenly region. In the sublunary world, the basic elements were earth, air, fire, and water, which had natural motions and places.
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Isaac Newton was an English scientist who made seminal contributions to physics, including formulating the laws of motion and universal gravitation. He discovered that white light comprises a spectrum of colors and that gravity explains the motions of celestial bodies. Newton published his theories and laws in Philosophiae Naturalis Principia Mathematica. He served as a professor of mathematics at the University of Cambridge and was considered the greatest genius of his time.
This document summarizes the rules and questions from the UTSUK '14 quiz competition. The rules state that questions can be answered by the team asked or opposing teams who "pounce". Pounces must be answered within 30 seconds. Correct answers receive 10 points, wrong answers receive -5 points. The questions cover topics in meteorology, astronomy, history of science and technology, chemistry, and geology. Sample questions ask about rain shadows, sunspots, the limelight, vanishing spray, eye color determination, columnar basalt, and the synthesis of paracetamol. The document provides a high-level overview of the format and content of the quiz competition.
The group presentation provides biographical information about Albert Einstein and summarizes his theory of relativity and equation E=MC2. It discusses Einstein's life and career, including being born in Germany but later having to leave due to his Jewish heritage. The presentation also covers the social, economic, political, and mathematical contexts surrounding Einstein's work, and provides an example using the principle of conservation of energy to illustrate his equation equating energy and mass.
This document is a presentation on entropy that contains sections on the history, concept, definition, expressions, classifications, applications, and conclusions of entropy. It begins with introducing entropy and its origins from Rudolf Clausius in 1854. It then discusses entropy as a measure of disorder and the number of microscopic states a system can be in. The document defines entropy using Boltzmann's constant and covers the classification of entropy including thermodynamic, statistical, and quantum entropy. It concludes that entropy is a measure of disorder that increases over time according to the second law of thermodynamics.
The document discusses several experiments from 1905-1925 that provided evidence that challenged classical physics and led to the development of quantum theory, including:
- Heat capacity experiments showing heat capacity decreases with temperature, contradicting classical physics (1905-1906)
- Photoelectric effect experiments showing electrons ejected by frequency-dependent photons, not intensity (1905)
- Atomic spectroscopy experiments showing atoms absorb/emit only discrete frequencies (1885, early 1900s)
This document provides biographical information on several scientists from history:
- David Brewster - A Scottish physicist known for contributions to optics and inventions like the kaleidoscope.
- Abraham Brook - An English bookseller who also conducted experiments in electricity and vacuum technology.
- František Josef Gerstner - A Bohemian physicist and engineer who helped establish technical schools and studied applied mechanics.
- Johannes Gessner - A Swiss mathematician, physicist and physician seen as the founder of a natural science society in Zurich.
- Johann Baptiste Horvath - A Hungarian Jesuit professor known for authoring physics and other textbooks that were widely distributed.
- Pierre Lemonnier -
The document discusses the physics of galaxy cluster plasmas, including convection processes like the Magnetothermal Instability (MTI) and Heat Flux-Driven Buoyancy Instability (HBI) that are driven by anisotropic thermal conduction. While clusters appear to be in global thermal equilibrium, local thermal instability can occur where the cooling time divided by the free-fall time is less than 10, allowing multiphase gas structures to form through thermal instability. Cosmological simulations show that heating from processes like AGN can self-regulate clusters to maintain a minimum cooling-to-free-fall time ratio of around 10 and minimum central entropy of 10-30 keV cm2, consistent with observations.
Here is a summary of the key points about carbon's atomic structure based on the information provided:
- Carbon has 6 protons and 6 neutrons in its nucleus.
- Its mass number is 12 and atomic number is 6.
- The number of protons equals the atomic number of 6.
- The number of neutrons is the mass number (12) minus the atomic number (6), which is 6.
- The number of electrons orbiting the nucleus equals the number of protons, which is 6.
So in summary, carbon has 6 protons and 6 neutrons in its nucleus, and 6 electrons orbiting the nucleus.
The document discusses the history of the atomic theory from ancient philosophers to modern scientists. It describes early thinkers like Thales who discovered static electricity but did not connect it to atoms. Democritus in 400 BC proposed that all matter is made of indivisible atoms that differ in shape and size. In the 1800s, Dalton, Dobereiner, and Berzelius conducted experiments that provided evidence for the atomic theory. Mendeleev organized the known elements into the first periodic table in 1869. In the early 1900s, Thomson discovered the electron, Rutherford proposed the nuclear model of the atom, and Moseley ordered the elements by atomic number, correcting Mendeleev's table.
This document provides biographical details about Albert Einstein's life and career. It describes key events such as his education in Germany and Switzerland, early work at the Swiss Patent Office, "miracle year" of 1905 when he published four groundbreaking papers on light quanta, photoelectric effect, Brownian motion, and special relativity, development of his general theory of relativity between 1907-1915, and verification of his theory through observations of star positions during a solar eclipse in 1919. The document establishes Einstein as a revolutionary physicist who changed our understanding of space, time, light, and gravity through his scientific theories.
Democritus first proposed the existence of atoms in 460 BC, though the atomic theory was not widely accepted until John Dalton proposed it in 1803 based on the laws of multiple and constant proportions. The discovery of subatomic particles like the electron by J.J. Thomson in 1897 and proton by Rutherford in 1911 led to proposed atomic models like the plum pudding model and nuclear atom. Defining the mass and charge of these particles along with isotopes observed by Francis Aston and the neutron discovered by James Chadwick in 1932 completed the basic components of the modern atomic theory.
The document provides a timeline of important discoveries and developments in the understanding of the atom from ancient Greek philosophers Democritus and Aristotle up to the early 20th century. It describes key contributions such as Democritus' idea that all matter is made of indivisible atoms, Dalton introducing atomic theory in 1802, Mendeleev organizing the periodic table in 1869, Thomson discovering the electron in 1897, Rutherford proposing the nuclear model of the atom in 1911, and Moseley ordering the elements by atomic number in 1913.
The document discusses the contributions of several famous scientists to the field of physics, including C.V. Raman who discovered the Raman effect and won the 1930 Nobel Prize, Albert Einstein who developed the theories of special and general relativity and won the 1921 Nobel Prize, Sir Isaac Newton who formulated the laws of motion and universal gravitation, and Archimedes who invented machines and formulated principles of hydrostatics and levers.
This document discusses heat transfer and thermodynamics. It begins by defining heat transfer as the science of calculating the rate at which heat flows within or between mediums. Thermodynamics deals with energy transfers that cause systems to change equilibrium states. The document then discusses the different methods of heat transfer: conduction, convection, and radiation. It provides examples and explanations of each type. The remainder of the document focuses on conduction and convection in more detail, explaining concepts like thermal conductivity, thermal resistance, boundary layers, and free and forced convection.
Sir Isaac Newton was an influential English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian. In his Philosophiae Naturalis Principia Mathematica, published in 1687, he described universal gravitation and the three laws of motion, laying the groundwork for classical mechanics. Newton showed that terrestrial and celestial motions are governed by the same laws and helped advance the scientific revolution. He also made important contributions to optics, mathematics, and astronomy.
Geologists used new evidence from physics, including radioactive dating and heat sources within the Earth, to show that the Earth was older than physicists had estimated based on cooling models alone. Lord Kelvin had estimated the Earth's age as between 20-40 million years based on cooling rates, but radioactive elements provided additional heat sources and evidence that the Earth was at least 1.6 billion years old. By considering multiple heat sources and dating methods, geologists and physicists reconciled differing age estimates to establish that the Earth was over 3 billion years old.
Geologists used various dating methodologies involving ocean chemistry, erosion rates, and radiometric dating to determine that the Earth is billions of years old, contradicting earlier estimates by physicists like Kelvin of only millions of years based on cooling models. The discovery of radioactivity provided a major new heat source inside the Earth and revealed processes like radioactive decay that allowed for much older dating of rocks and minerals, establishing the age of the Earth to be over 4 billion years.
This document provides an overview of Aristotle and his works. It discusses that Aristotle was a student of Plato and established his own school called the Lyceum. Aristotle focused on empirical knowledge gained from observation and experience, in contrast to Plato who believed true knowledge came from contemplation. Aristotle made detailed classifications of phenomena and employed logic and reasoning. However, his conclusions were sometimes flawed due to incorrect generalizations. The document examines Aristotle's theories of causation, motion, and his cosmological model of the spherical earth surrounded by nested spheres carrying the sun, moon, and planets in uniform circular motion.
Aristotle was a student of Plato who established his own school called the Lyceum in Athens. He tutored Alexander the Great for several years. Aristotle's works were based on careful observation and classification of the natural world. He developed logic and identified four causes to explain things: material, formal, efficient, and final. Aristotle built a complete system to explain the world, dividing it into a changing sublunary region and a fixed heavenly region. In the sublunary world, the basic elements were earth, air, fire, and water, which had natural motions and places.
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
This presentation was provided by Racquel Jemison, Ph.D., Christina MacLaughlin, Ph.D., and Paulomi Majumder. Ph.D., all of the American Chemical Society, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
The chapter Lifelines of National Economy in Class 10 Geography focuses on the various modes of transportation and communication that play a vital role in the economic development of a country. These lifelines are crucial for the movement of goods, services, and people, thereby connecting different regions and promoting economic activities.
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
This presentation was provided by Rebecca Benner, Ph.D., of the American Society of Anesthesiologists, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
1. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
A few words…
Time used to be measured by the change of the moon…
Now it is measured by the 2 ns between two sms!
Instruments and techniques have changed.. have been developed, evolved or
disappeared… new ones appear… faster, better… maybe more accurate, or not!
and computers have become so much faster…
In this section, we will walk through history
to see the evolution and development of the THW technique…
Not a thorough list of dates, numbers and equations
but through designs and drawings of instruments.
From Gases to Liquids, to Melts and Solids,
and it is Still Going Strong!
The section will include a typical selection of instruments in
order to demonstrate its evolution
and will certainly not include all investigators.
M.J. Assael, K.E. Antoniadis, W.A. Wakeham, Int. J. Thermophys. 31:1051-1072 (2010).
1/43 M.J. Assael, K.E. Antoniadis, Proc. 30th Int. Therm. Conduct. Conf. & 18th Int. Therm. Expansion Symp. 28 Aug. - 3 Sept. Pittsburg
(2009).
2. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
A few more words…
fluid Ideally, the thermal conductivity of the fluid is determined by observing
the rate at which the temperature of a very thin metallic wire increases
q (W/m) with time after a step change in voltage has been applied to it, thus
creating in the fluid a line source of essentially constant heat flux per
unit length.
Approximate analysis (Healy 1976)
wire
q
ln( 4kt )
of radius α q
ΔTid = ΔΤ
4πλ α2C ρCp? 4πλ
ΔTid = ΔΤw + Σ δTi
t
However today, It is much better,
and much more accurate, to solve ΔΤ
the full heat transfer equations for
the wire and the fluid by FEM. whole curve ρCp & λ
No approximations!
t
2/43 J.J. Healy, J.J. de Groot, and J. Kestin, Physica C, 82:392 (1976).
3. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1780 - 1888
The early days
3/43
4. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1780 J. Priestley GLNMS
Joseph Priestley was probably the first, to carry out experiments
to measure the gas' power to conduct heat
(i.e. the specific heat, which was unknown at that time…).
In 1780, Joseph Priestley became a minister in Birmingham. He continued his
scientific researches and also his theological ones. He expressed his views quite
forcibly, and, in 1785, his History of the Corruptions of Christianity was publicly
burned.
In 1791, Priestley was driven out of Birmingham by a mob who destroyed his
home. He had expressed support for the French Revolution, and so, on the
second anniversary of the storming of the Bastille, the mob burned down his
laboratory, which was at his home. He moved to USA.
4/43
5. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1786 Count Rumford (Sir Benjamin Thomson) GLNMS
Count Rumford continued similar experiments examining
"the conductive power of artificial airs or gases" and while doing so
he stumbled on a completely new mode of heat transfer, convection.
In 1799
Count Rumford concluded that "a gas was unable to conduct heat"!!!
"Heat is incapable of passing through a mass of air, and that it is
to this circumstance that its non-conducting power is principally owing"
and because of his reputation, this conclusion was not challenged
for many years.
B. Thomson, Trans. Roy. Soc. London, 76:273-304 (1786).
5/43 B. Thomson, "Essays, Political Economical, and Philosophical”, 1 st Am. Ed. vol 2:457 (1799).
A.C. Burr, Isis, 21:169-186 (1934).
6. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1804 Sir John Leslie GLNMS
Sir John Leslie in "An Experimental Inquiry into the
Nature and Propagation of Heat" (1804),
wrote about Count Rumford:
"A late ingenious experimenter, who by the
perspicuity and useful tendency of his writings, is
deservedly a favorite of the public, he advanced
the paradoxical conclusion that
fluids are non-conductors of heat …..
If the proposition, however, be taken in its strict
sense, it is more palpably erroneous.
Were fluids absolutely incapable of conducting heat,
how could they ever become heated?...
How could water, for instance, be heated by the
content of warm air?
But the question really deserves no serious
discussion“.
6/43 J. Leslie, "An Experimental Inquiry into the Nature and Propagation of Heat", Ist Ed, p.552 (1804).
7. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1848 Sir William Robert Grove GLNMS
In a communication illustrated by an experiment, he showed, that a
platinum wire, rendered incandescent by a voltaic current, was cooled far
below the point of incandescence when immersed in an atmosphere
of hydrogen gas.
"This was found not to be due to specific heat, nor to the conducting
powers of the gases. Convection did not explain the fact; and
considerable difficulty was found, upon examination, to exist,
if it was attempted to refer it to the greater mobility of the particles
of hydrogen gas, the tightest known, than of either oxygen, nitrogen,
or carbonic acid. It was found that this peculiar property also belonged,
but to a less extent, to all the compounds of hydrogen and carbon".
NOTE : First experiments with heated wires...
7/43 W.R. Grove, Phil. Mag. Series 3, 27:442-446 (1845).
W.R. Grove, J. Franklin Institute, 46:358 (1848).
8. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1861 Gustav Magnus GLNMS
Gustav Magnus reported in Poggendorf's Annalen, immediately being
translated into English and appearing in full in the Philosophical Magazine.
"A platinum wire is less strongly heated by a galvanic current
when surrounded by hydrogen than when it is in atmospheric air
or any other gas.
It cannot be doubted that hydrogen conducts heat,
and that in a higher degree than all other gases".
NOTE first experiments with heated wires….
G. Magnus, Phil. Mag. Series 4, 22:85-106 (1861).
8/43
G. Magnus, J. Franklin Institute, 72:130-132 (1861).
9. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1863 John Tyndall GLNMS
John Tyndall in his book "Heat considered as a Mode of Motion" writes:
"The subject of gaseous conduction has been recently taken by Prof.
Magnus of Berlin, who considers that his experiments prove that
hydrogen gas conducts heat like a metal….
Beautiful and ingenious as these
experiments are (Magnus & Grove), I do
not think they conclusively establish the
conductivity of hydrogen…. Theories are
indispensable, but they sometimes act like
drugs upon the mind. Men grow fond of
them as they do of dram-drinking…"
Hot-wire employed by Tyndall
9/43 J. Tyndall, "Heat considered as a Mode of Motion", 1 st Ed. p.239 (1863)
10. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1860 James Clerk Maxwell GLNMS
James Clerk Maxwell publishes his groundbreaking paper on the
dynamic theory of gases and he calculates a theoretical value of the
thermal conductivity of a gas and showed its dependence on
temperature and pressure.
1862
Rudolf Julius Emanuel Clausius backs up Maxwell, showing that
thermal conductivity increased with temperature and was independent
of pressure when the gas was ideal.
J. C. Maxwell, Phil. Mag. Series 4, 19:19-32 (1860).
J. C. Maxwell, Phil. Mag. Series 4, 20:21-37 (1860).
10/43 R.J.E. Clausius, Phil. Mag. Series 4, 23:417-435 (1862).
R.J.E. Clausius, Phil. Mag. Series 4, 23:512-534 (1862).
11. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1872 Josef Stefan GLNMS
Josef Stefan with his experimental expertise (E=AT 4 law)
set out to defy Maxwell's words (Boltzmann was his
student).
He measured thermal conductivity of air with
diathermometer
(23.4 mW/mK - today's value is 26.3 mW/mK).
The diathermometer's principle was based on the energy
balance equation
-kA
T dr = dQ = mC dT
s
Δx
Rearranged to be expressed as a measure of pressures, as
Τ λA ΔΡ
Το = exp(- mC Δx t) = ΔP
s o
J. Stefan, Mathematische-Naturwissenschaftliche Classe Abteilung 2, 65:45-69 (1872).
11/43 J. Crepeau, Exper. Thermal & Fluid Sci., 31:795-803 (2007).
12. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1888 August Schleiermacher GLNMS
August Schleiermacher following the work of Josef Stefan and
his predecessors set out to measure the thermal conductivity of gases
by using a Pt hot wire (probably first real application of Hot Wire)
Pt wire diameter 0.4 mm length 32 cm.
Glass diameter 2.4 cm.
Leads are soldered at A and B.
Temperature outside registered by
a wound resistance thermometer.
Inside by measuring the resistance
of wire. Equilibrium reached in minutes.
Measured up to 1000 oC.
When equilibrium is reached, measure I, V through wire and T1 and T2
Q
λ=Α A = ln(d2/d1)/(2πl) or by measuring known gas.
(T1-T2)
12/43 A. Schleiermacher, Annalen der Physik und Chemie, 270:623-646 (1888).
3/13
13. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
The early days…
1780 G First experiments in
conduction
(J. Priestley)
1786 G "Gases do not conduct"
(Count Rumford)
1804 G Can not be so..
(J. Leslie)
1848-61 G First experiments with
heated wires
(W.R. Grove & G. Magnus)
1863 G Still doubts about
conduction
(J. Tyndall)
1860-62 G Thermal conductivity
theory
(J.C. Maxwell & R.J.E. Clausius)
1872 G Thermal conductivity
measurement
(J. Stefan)
1888 G First hot wire - horizontal
4C
(A. Schleiermacher)
13/43
14. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1888 - 1971
The evolution of
the Transient Hot-Wire
14/43
15. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1917 Sophus Weber GLNMS
The sources of errors involved in the determination of the
thermal conductivity of gases by Schleiermacher’s method
are subjected to a critical analysis, and a modified form of
apparatus is described in which the errors due to convection
are greatly reduced.
Apparatus is placed vertically. With this improved form of
apparatus, measurements of the thermal conductivity of a
number of gases have been made.
Pt wire
The following values are recorded : 54.5 cm length,
@ 0 oC mW/m/K 0.40 mm diameter.
hydrogen. 174 168.4 internet
neon, 45.5 49.2 (25 oC)
Glass
helium, 144 155.3 (25 oC)
diameter 2.3 cm.
argon, 16.1 16.6 Ref.val.
nitrogen, 23.7 24.9 Ref.val.
oxygen, 24.1 25.5 Ref.val.
methane, 30.1 32.7 Ref.val.
CO2 16.4 16.3 Ref.val.
N2O 14.7 14.6 internet
15/43 S. Weber, Annalen der Physik, 21:325-356 (1917).
S. Weber, Annalen der Physik, 54:437-462 (1917).
16. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1931 Bertil Stâlhane & Sven Pyk GLNMS
First transient hot wire.
Employed to measure thermal conductivity
of solids and powders (& liquids). They
investigated the relationship between time
and temperature rise, for a fine straight wire
subjected to a step change in the heat input
to the wire. They found that a short interval
after the initiation of the step change, the
following empirical relation holds:
2 A, B were found using fluids of
ΔΤ = Aq ln( ro + B)
λ t known thermal conductivity.
On the diagram above, the wire is placed in the middle of powder. The upper and lower
solids are kept at constant temperature. Temperatures are recorded by thermocouples.
The diagram on the right shows another sensor for powders with a thermometer in the
middle.
16/43 B. Stâlhane and S. Pyk, Teknisk Tidskrift, 61:389-398 (1931).
17. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1938 A. Eucken & H. Eglert GLNMS
They designed an absolute THW for low temperatures.
The 0.1mm Pt wire is in the middle of the glass tube.
- two wires serve as potential leads, and
- two wires as supports.
Temperature obtained from the wire's resistance.
Thermal conductivities measured were:
- Benzene (0 to -78.5 oC),
- Glycerin (0 to -78.5 oC),
- Carbon dioxide (-103.9 oC),
- Ammonia (-103.9 oC).
17/43 A. Eucken and H. Englert, Zeitschrift fur die gesamte Kalte-Industrie, 45:109-118 (1938).
18. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1949 E.F.M. van der Held & F.G. van Drunen (Rijksuniversiteit Utrecht) GLNMS
A Proved the empirical expression of Stâlhane & Pyk for the THW, by solving
the Fourier equation
q q
ΔΤ = [-Εi (- 4αt )] ΔΤ = [ln 4αt - 0.5772… ]
4πλ r2 4πλ ro2
This can further be simplified by taking the difference in temperatures at
two times as
ΔΤ
q t
ΔΤ1 - ΔΤ2 = ln 2 λ
4πλ t1
ln t
This way absolute measurements can be carried out.
E.F.M. van der Held and F.G. van Drunen, Physica, 15:865-881 (1949).
18/43 E.F.M. van der Held, J. Hardebol, and J. Kalshoven, Physica, 19:208-216 (1953).
19. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1949 E.F.M. van der Held & F.G. van Drunen (Rijksuniversiteit Utrecht) GLNMS
B In order to develop a method for all liquids they used
- a 0.3 mm diameter Mn wire and
- a 0.1 mm diameter Copper/Constantan thermocouple
both placed in a narrow capillary with both ends fused into
the wall of a glass vessel. Liquid is placed between the
capillary and the glass vessel.
The glass vessel is placed in a Dewar flask for a steady
temperature.
They preferred to use thermocouple to record temperatures instead of
recording the resistance of the wire, as the later would involve high
temperature rises and complicated recorders and bridges.
They made many corrections for the wire thickness and the presence of
the glass and employed times in the region of 20-50 s.
Measured the thermal conductivity of many fluids (hydrocarbons,
alcohols, acids..) with a quoted uncertainty of ±2%.
E.F.M. van der Held and F.G. van Drunen, Physica, 15:865-881 (1949).
19/43 E.F.M. van der Held, J. Hardebol, and J. Kalshoven, Physica, 19:208-216 (1953).
20. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1952 D.A. de Vries (Landbouwhogeschool Holland) GLNMS
De Vries employed a small modification of the original solution
q q
ΔΤ = [ln 4αt - 0.5772… ] ΔΤ = [d + ln(t + to ]
4πλ r2 4πλ
Heating wire 0.1 mm diameter enameled constantan folded and placed
inside the glass capillary of 0.4 mm outside diameter. Outside the capillary
there is a fine monel gauze forming a socket of 1.4 mm diameter.
The thermocouple wires are of enameled copper and constantan 0.1mm.
The thermocouple wires and the glass capillary are introduced into the gauge
cylinder, and the empty space is filled with paraffin wax. The whole sensor has
a length of 10 cm.
Resistance is measured with a sensitive D.C. Wheatstone bridge.
Times of 3 min were employed.
Daily trends in moisture content of soil reflected on the measurement of the
thermal conductivity.
20/43 D.A. de Vries, Soil Science, 73:83-89 (1952).
21. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1955 D.G. Gillam, L. Romben, H.-E. Nissen, O.Lamm (Stockholm) GLNMS
They employed the ideas of Stâlhane & Pyk, and Eucken &
Englert to produce a simpler apparatus of lower uncertainty,
0.3% for liquids and solids (of low melting point - melted
solid, like liquid was poured into the glass and solidified
there).
They presented advances in the THW theory, and
discussed zero time determination and specific heat
capacity correction.
Temperature obtained from the wire's resistance.
Pt Wire of 0.1 mm diameter and 10 cm length.
Potential leads also welded Pt wires.
Optimized Kelvin bridge to record accurately the resistance change.
Times recorded between 1 - 60 s.
21/43 D.G. Gillam, L. Romben, H.-E. Nissen, and O. Lamm, Acta Chemica Scandinavica, 9:641-656 (1955).
22. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1960 P. Grassman, W. Straumann (ETH Zurich) GLNMS
They employed a relative THW, i.e. two THW
one with a know thermal conductivity fluid, and
the other with the unknown, both placed in the
arms of a Wheatstone type bridge.
Heating lasted a few seconds, and the quoted
uncertainty was ±1%.
Pt Wire of 70 μm diameter and 15 cm length.
They registered resistance change from very low times
(interesting diagram) but only employed top part to obtain
the thermal conductivity.
22/43 P. Grassman, and W. Straumann, Int. J. Heat Mass Transfer, 1:50-54 (1960).
23. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1960 W.E. Haupin (New Kensington) GLNMS
He determined the thermal conductivity by placing into the
specimen a line heat source consisting of a butt welded
thermocouple heated by alternating current. At the same
time, a filter network was used to eliminate the ac heating
specimen
current allowing the thermocouple emf to be measured.
The thermocouple served both as a heat source and a
thermometer.
Materials measured were high-fired, superduty, firebricks and furnace
insulation blocks.
23/43 W.E. Haupin, Am. Ceram. Soc. Bull., 39:139-141 (1960).
24. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1961 A.G. Turnbull (Melbourne) GLNMS
He employed a THW to measure thermal conductivity of molten salts
both in liquid and solid state near their melting point (to confirm his theory
on molten salts).
Many salts like NaNO3, KNO3, NaCl, AgNO3, KHSO4, NH4HSO4, KCNS, ZnCl2, NaOH.
24/43 A.G. Turnbull, Aust. J. Appl. Sci., 12:325-329 (1961).
25. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1963 J.K. Horrocks, E. McLaughlin (Imperial College, London) GLNMS
Four-terminal THW, for the measurement of the
thermal conductivity of liquids with an absolute
uncertainty 0.25%.
Full analysis of corrections a) finite wire diameter,
b) boundary medium, c) finite wire length, d) study
of convection and radiation.
1 cm diameter Glass cell.
60 μm Pt wire of 15 cm length, annealed for an hour.
Pt potential leads 1 cm from ends.
Pt spring at top (inside Pt strips) prevents wire sagging.
Measurements performed within 30s.
Temperature rise was calculated from the wire's resistance change.
25/43 J.K. Horrocks and E. McLaughlin, Proc. Roy. Soc. , A273:259-274 (1963).
26. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1964 A. von Mittenbuhler GLNMS
The method employs a heating wire of one metal with a thermocouple
welded to the heating wire in the form of a cross. An ac or dc power suplly
can be employed, and the temperature rise generated by a known heating
power is used to determine the thermal conductivity.
The technique formed the basis for a German and a European
standard in use today.
A. von Mittenbuhler, Ber. Dtsch. Keram. Ges. 41:,15 (1964).
Deutsches Institut für Normung. 1976. Testing of Ceramic Materials: Determination of Thermal Conductivity up to 1600oC by the Hot-Wire Method.
Thermal Conductivity up to 2 W/m/K. DIN 51046.
26/43 European Committee for Standardization. 1998. Methods of Testing Dense Shaped Refractory Products. Part 14: Determination of Thermal Conductivity
by the Hot-Wire (Cross-Array) Method. EN 993-15.
27. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1968 Harland L. Burge, Lawrence Baylor Robinson (California Univ.) GLNMS
Four-terminal
THW, for the
measurement of
the thermal
conductivity of
gases.
The line source consists of a 0.7 mm diameter, 20.6 cm length wire (alloy "evenohm"). Around it is tightly
wrapped a 0.02 mm nickel temperature sensing coil. A 3-element copper-constantan thermocouple
records gas temperature.
Resistance change is recorded by a camera attached to a Tetronik oscilloscope connected to a dc
resistance bridge. Times were limited to 0.27 s and temperature rise never exceed 10 oC.
Thermal conductivity of He, Ne, Ar and their mixtures was measured.
27/43 H.L. Burge, and L.B Robinson, J. Appl. Phys., 39:51-54 (1968).
28. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 K. Hayashi, M. Fukui, I. Uei (Kyoto Tech. Univ.) GLNMS
Four-terminal THW, for solids
up to 1200 OC.
Wire:
0.3 mm diameter (constantan, alumel, Pt-Rh-13%)
combined with thermocouple (chromel-constantan, chromel-alumel, Pt-Pt Rh13%).
Measured thermal conductivity of fire clay brick, high alumina brick, chromite-magnesia brick. etc
28/43 K. Hayashi, M. Fukui, and I. Uei, Mem. Fac. Ind. Arts, Kyoto Tech. Univ. Sci. Tech., 81-103 (1971).
29. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 E. McLaughlin, J.F.T. Pittman (Imperial College, London) GLNMS
A Four-terminal THW, for liquids,
100-450 K and up to 10 MPa.
Discussion on the ideal solution and following approximations:
a) temperature dependent fluid properties,
b) finite wire diameter,
c) finite conductivity wire,
d) wall effects,
e) interfacial thermal resistance,
f) time-dependent heat-source power,
g) end effects,
h) initial fluid temperature distribution.
29/43 E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:579-602 (1971).
E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:557-578 (1971).
30. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 E. McLaughlin, J.F.T. Pittman (Imperial College, London) GLNMS
B Four-terminal THW, for liquids,
100-450 K and up to 10 MPa.
Cell:
1 cm diameter SS.
Wire:
25 μm diameter 15 cm length Pt.
1 cm from ends Pt potential leads.
Small weight at the bottom
ensures verticality.
Wire annealed for 15 min.
Elaborate temperature enclosure (heating and liquid nitrogen) with stability of
1mK/h.
Measurement time 1 - 20 s.
Instead of photographing galvanometer spots or using chart recorders, a digital
voltmeter is employed to record the change in voltage because of the change in
resistance. Temperature change is calculated from the wire's resistance.
30/43 E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:579-602 (1971).
E. McLaughlin, and J.F.T. Pittman, Phil. Trans. R. Soc. Lond., A 270:557-578 (1971).
31. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 P.S. Davis, F. Theeuwes, R.J. Bearman, R.P. Gordon (Kansas Univ.) GLNMS
Four-terminal THW, for electrically conducting liquids and salts.
Wire:
6.2 μm diameter Pt wire of 1.3 cm length.
0.3 cm from ends Pt potential leads (T-shaped junction).
Measurement time 1 - 10 s.
Instead of photographing galvanometer spots or using chart recorders, a digital
voltmeter (HP 2402A, 40 measurements/s) is employed to record the change in
voltage because of the change in resistance, coupled to a precision frequency
generator. Temperature change is calculated from the wire's resistance.
For electrically conducting fluids they used a thin metal film evaporated on a quartz rod. The quartz
substrate rod was 1.25 mm long and had a diameter of 0.025 mm. The length of the sensing platinum film
was 0.51 mm. The film is in contact with both ends with gold plated portions of the quartz rod. The
resistance of the sensor was about 6 Ohm. This was employed as a relative instrument.
31/43 P.S. Davis, F. Theewesm R.J. Bearman, and R.P. Gordon, J. Chem. Phys., 55:4776-4783 (1971).
32. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 J.W. Haarman (Delft) GLNMS
His equipment used an automatic Wheatstone bridge to measure the resistance
difference of two wires. The two wires were identical except for their length. Hence, end
effects were subtracted.
The bridge was also equipped with an electronic potential comparator. The bridge was
capable of measuring the time required for the resistance of the hot wire to reach six
predetermined values, with the aid of high-speed electronic switches and counters.
This new bridge made possible a ten-fold reduction in the duration of each
experimental run, eliminated completely the effects arising from convection and
reduced greatly other time-dependent errors.
J.W. Haarman, Physica, 52:605-619 (1971).
32/43 J.W. Haarman, Ph.D thesis, Technische Hogeschool Delft, Netherlands (1969).
33. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
The early days… & The evolution of the Transient Hot Wire
1780 G First experiments in 1952 STHW, 3 min, T=f (t/c)
conduction (D.A. de Vries)
(J. Priestley)
1955 LS THW, 1-60 s, T=f (R)
1786 G "Gases do not conduct" (D.G. Gillam, L. Romben, H.-E. Nissen, O.Lamm )
(Count Rumford)
1960 GL 2 THW in Wheatstone bridge, 1-20 s
1804 G Can not be so.. (P. Grassman & W. Sraumann)
(J. Leslie)
1960 S THW
1848-61 G First experiments with (W.E. Haupin)
heated wires
1961 MS THW
(W.R. Grove & G. Magnus)
(A.G. Turnbull)
1863 G Still doubts about
1963 L THW, analysis of errors, 30 s, T=f (R)
conduction
(J. Tyndall)
(J.K. Horrocks & E. McLaughlin)
1860-62 G Thermal conductivity
1964 STHW + t/c cross (basis for D & EU standards)
theory
(A. von Muttelbuhler)
(J.C. Maxwell & R.J.E. Clausius)
1968 G THW, 30 s, T=f (t/c)
1872 G Thermal conductivity
(H.L. Burge & L.B. Robinson)
measurement
(J. Stefan) 1971 STHW, up to 1200'C, T=f (t/c)
(K. Hayashi, M. Fukui, I. Uei)
1885 G First hot wire - horizontal
4C 1971 L THW, T=f (R), 20 s, Digital
(A. Schleiermacher) voltmeter
(E. McLaughlin & J.F.T. Pittman)
1917 G Vertical hot wire
(S. Weber) 1971 LSmall THW, 10 s, digital voltmeter
(P.S. Davis,F. Theewes,R.J. Bearman,R.P. Gordon)
1931 LS First transient hot wire, & theory
33/43 (B. Stâlhane & S. Pyk) 1971 L2 wires, new, much faster electronic bridge
(J.W. Haarman)
1938 GL Absolute THW, T=f (R)
(A. Eucken & H. Eglert)
35. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 today
The pioneering work of Haarman (use of 2 wires, faster electronic bridge, experimental
time of seconds) was the start of a new series of THW instruments developed after 1971,
most of them based theoretically in a paper by Healy in 1976.
Since the majority of these new groups cooperated through research projects, very
similar instruments appeared. Hence, they will be presented all together.
Most of the THW groups nowdays originated from, or were connected to,
- J. Kestin (Brown Univ., USA), or
- W.A. Wakeham (Imperial College & Southampton Univ., UK).
Such groups are:
- C.A. Nieto de Castro & J.M.N.A. Fareleira (Portugal),
- M.J. Assael (Aristotle Univ., Greece),
- R. Perkins (NIST, U.S.A.),
- A. Nagashima & Y. Nagasaka (Keio Univ., Japan).
and more recently
- J. Wu (Jiaotong Univ., China),
- E. Vogel (Rostock Univ., Germany).
In parallel, some more groups produced also excellent work, as
- S.E. Gustaffson (Chalmers Univ., Sweden),
- U. Hammerschmidt (PTB, Germany).
35/43 J.J. Healy, J.J. de Groot, and J. Kestin, Physica C, 82:392 (1976).
36. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 today Development of THW Instruments for fluids GLNMS
(anodized)
Au
(a) (b) (c) (d) (e)
(a) J.J. de Groot, J. Kestin, and H. Sookiazian, Physica, 75:454-482 (1974).
C.A. Nieto de Castro, J.C.G. Calado, W.A. Wakeham, and M. Dix, J. Phys. E: Sci. Instrum., 9:1073-1080 (1976).
(b) J. Kestin, R. Paul, A.A. Clifford, and W.A. Wakeham, Physica, 100A:349-369 (1980).
M.J. Assael, M. Dix, A. Lucas, and W.A. Wakeham, J. Chem.Soc.,Faraday Trans. I, 77:439-464 (1981).
E.N. Haran, and W.A. Wakeham, J. Phys. E: Sci. Instrum.,15:839-842 (1982).
(c) J. Menashe, and W.A. Wakeham, Ber. Bunsenges. Phys. Chem., 85:340 (1981).
Y. Nagasaka, and A. Nagashima, J. Phys. E: Sci. Instrum., 14:1435-1440 (1981).
W.A. Wakeham, and M.Zalaf, Physica, 139:105 (1986).
E. Charitidou, M. Dix, C.A. Nieto de Castro, and W.A. Wakeham, Int. J. Thermophys., 8:511-519 (1987).
36/43 (d) S.H. Jawad, M.J. Dix, and W.A. Wakeham, Int. J. Thermophys., 20:45-54 (1999).
(e) M.J. Assael, C-F. Chen, I. Metaxa, and W.A. Wakeham, Int. J. Thermophys. 25:971-985 (2004) .
37. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 today Development of THW Instruments for melts & solids GLNMS
(h)
(g)
(f)
(i)
(f) M.J. Assael, K.D. Antoniadis, K.E. Kakosimos, and I.N. Metaxa, Int. J. Thermophys., 29:445-456 (2008).
(g) M.V. Peralta-Martinez, M.J. Assael, M. Dix, L. Karagiannidis, and W.A. Wakeham, Int. J. Thermophys., 27:353-375 (2006).
37/43 (h) R. Model, R. Stosch, and U. Hammerschmidt, Int. J. Thermophys., 28:1447-1460 (2007).
(i) S.E. Gustafsson, Rev. Sci. Instrum., 62:797-804 (1991).
38. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 today Development of THW automatic bridges GLNMS
Electronic bridges were developed tremendously following advances in electronics and
computers. An excellent series of bridges was developed in Imperial College by M. Dix,
and these are shown here as example.
(a) (b) (c)
(a) J.J. de Groot, J. Kestin, and H. Sookiazian, Physica, 75:454-482 (1974).
C.A. Nieto de Castro, J.C.G. Calado, W.A.Wakeham, and M. Dix, J. Phys. E: Sci. Instrum., 9:1073-1080 (1976).
J. Kestin, R. Paul, A.A. Clifford, and W.A. Wakeham, Physica, 100A:349-369 (1980).
M.J. Assael, M. Dix, A. Lucas, and W.A. Wakeham, J. Chem. Soc.,Faraday Trans. I, 77:439-464 (1981).
(b) G.C. Maitland, M. Mustafa, M. Ross, R.D. Trengove, W.A. Wakeham, and M. Zalaf, Int. J.Thermophys., 7:245-258 (1986).
38/43 M.J. Assael, E. Charitidou, G.P. Georgiades, and W.A. Wakeham, Ber.Bunsenges.Phys. Chem., 92:627-632 (1988).
(c) M.J. Assael, C-F. Chen, I. Metaxa, and W.A. Wakeham, Int. J. Thermophys., 25:971-985 (2004).
39. Introduction 1780 - 1888 1888 - 1971 1971 - today Conclusions
1971 today Measurement of the temperature rise GLNMS
As an example,
measurement of the thermal conductivity of BK7.
39/43 M.J. Assael, K.D. Antoniadis, and J. Wu, Int. J. Thermophys., 29:1257-1266 (2008).