The science of measurement
Lexical units:
ratio – отношение, коэффициент
traceability – возможность отслеживания
suitability – (здесь) допустимость
calibration – стандартизация
regulatory – регулирующий, нормативный
uncertainty – переменчивость, неопределённость
National Institute of Standards and Technology –
Национальный институт стандартов и технологий, Мэриленд, США
National Physical Laboratory –
Национальная лаборатория физики, Лондон, Англия
systematic bias – систематическая ошибка
leads – выводы, подводящие провода
to short – замыкать накоротко
qualifying conditions – определяющие условия
triple point – тройная точка
(равновесное нахождение вещества в трёх агрегатных состояниях)
potentiometer – делитель напряжения, потенциометр
influential – важный, имеющий влияние
to anticipate – предугадывать, упреждать
repeatability – сходимость результатов
reproducibility – воспроизводимость
to quantify – определять количество, измерять
TEXT
Under the science of measurement we know the metrology. It includes all theoretical and practical aspects of measurement. The word “metrology” comes from Greek “metron” (measure) and “logos” (study). In Ancient Greek the term “metrologia” meant “theory of ratios.”
Nowadays, metrology is a very broad field and it may be divided into three subfields. They are scientific (fundamental) metrology, applied (industrial) metrology, and legal metrology. The first one concerns the establishment of quantity systems, unit systems, units of measurement, the development of new measurement methods, realization of measurement standards and the transfer of traceability from these standards to users in society. Industrial metrology concerns the application of measurement science to manufacturing and other processes and their use in society, ensuring the suitability of measurement instruments, their calibration and quality control of measurements. Legal metrology concerns regulatory requirements of measurements and measuring instruments for the protection of health, public safety, the environment, enabling taxation, protection of consumers and fair trade.
A core concept in metrology is traceability defined as the property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons, all having stated uncertainties. The level of traceability establishes the level of comparability of the measurement: whether the result of a measurement can be compared to the previous one, a measurement result a year ago, or to the result of a measurement performed anywhere else in the world.
Traceability is most often obtained by calibration, i.e. establishing the relation between the indication of a measuring instrument and the value of a measurement standard. These standards are usually coordinated by such national laboratories as National Institute of Standards and Technology (USA), National Physical Laboratory, UK, etc. Traceability, accuracy, precision, systematic bias, evaluation of measurement uncertainty are critical parts of a quality management system.
Mistakes can make measurements and counts incorrect. Even if there are no mistakes, nearly all measurements are still inexact. The term “error” is reserved for that inexactness, also called measurement uncertainty. Among the few exact measurements are: 1) the absence of the quantity being measured, such as a voltmeter with its leads shorted together – the meter should read zero exactly; 2) measurement of an accepted constant under qualifying conditions, such as the triple point of pure water – the thermometer should read 273.16 Kelvin (0.01 degrees Celsius, 32.018 degrees Fahrenheit) when qualified equipment is used correctly; 3) self-checking ratio metric measurements, such as a potentiometer – the ratio here is independently adjusted and verified to be beyond influential inexactness.
All other measurements either have to be checked to be sufficiently correct or left to chance. Basically, metrology is the science that establishes the correctness of specific measurement situations. This is done by anticipating and allowing for both mistakes and error. The precise distinction between measurement error and mistakes is not settled and varies by country. Repeatability (variation in measurements taken by a single person or instrument on the same item and under the same conditions) and reproducibility (ability of a test or experiment to be accurately reproduced by someone else working independently) studies help quantify the precision.
Comprehension
Exercise 1.True or false?
1) The term “error” is reserved for measurement exactness.
2) Metrology is the science that establishes the correctness of specific measurement situations.
3) Traceability is often obtained by reproducibility.
4) The level of traceability establishes the level of comparability of the measurement.
5) The word “metrology” comes from the Latin language.
6) National Physical Laboratory is situated in the USA.
7) 273.16 degrees Kelvin are the same as 0.01 degrees Fahrenheit.
8) Legal metrology concerns the establishment of quantity systems, unit systems, units of measurement, etc.
9) Nearly all measurements are still inexact.
10) A voltmeter has two leads shorted together.
Exercise 2.Complete the sentences using the correct words from the text:
1) … includes all … and practical … of measurement.
2) Reproducibility is the … of a test or … to be accurately reproduced by someone else working ….
3) … metrology concerns the … of measurement science to … and other processes.
4) The … distinction between measurement … and … is not settled and varies by country.
5) Metrology is a very … field and it may be … into three ….
6) Repeatability and … studies help … the ….
7) Traceability, …, precision, evaluation of measurement … are critical parts of a … … system.
8) Among the few … measurements are …-… ratio … measurements.
Vocabulary
Exercise 3.Give the Russian or English equivalents for the following word combinations:
Establishment of quantity systems; возможность отслеживания в условиях неопределённости; anticipating and allowing for both mistakes and error; допустимость стандартных коэффициентов; application of measurement science to manufacturing; систематические ошибки, появляющиеся при измерениях; development of new measurement methods; определяющие условия для подключения вольтметра; variation in measurements taken by a single person or instrument; предоставление возможности отслеживания современных измерительных стандартов.
Exercise 4.Match the words with their meanings:
| 1) error | a) unit of temperature measurement on any of several scales |
| 2) laboratory | b) a number representing a comparison between two things |
| 3) ratio | c) something used as a measure for comparative evaluations |
| 4) application | d) accidental wrong action, a false statement not made deliberately |
| 5) standard | e) partial change in the form, position, state, etc., of a thing |
| 6) variation | f) room, building or institution equipped for scientific research or analysis |
| 7) degree | g) ratifying or ordaining; settlement; confirmation |
| 8) establishment | h) employment of means to accomplish an end; specific use |
Exercise 5.Translate from Russian into English:
1) Метрология – это наука об измерениях физических величин, методах и средствах обеспечения их единства, а также о способах достижения требуемой точности. 2) Предметом метрологии является извлечение количественной информации о свойствах объектов с заданной точностью и достоверностью. 3) Теоретическая метрология рассматривает такие общие теоретические проблемы, как разработка теории и проблем измерений, физических величин, их единиц. 4) Если бы целью метрологии не было создание общей теории измерений, эта наука потеряла бы смысл. 5) Учёные ввели в обращение широкое понятие физической величины для одного из свойств физического объекта. 6) Мы знали, что измерение – это нахождение значения физической величины опытным путём с помощью технических средств. 7) Отечественная метрология развивалась под контролем государства из-за потребности в повышении точности измерений в связи с ростом промышленного комплекса. 8) Зарубежная метрология также возникла из-за практических требований, но эти требования исходили, в основном, от частных фирм. 9) Средством метрологии является совокупность измерений и метрологических стандартов, которые обеспечивают необходимую точность. 10) В странах Западной Европы частная фирма может не пользоваться плохо зарекомендовавшим себя стандартом или прибором и договориться с партнёрами о другом варианте подтверждения измерений.
Exercise 6.Make up the summary of the text and write its annotation.
Discussion
Exercise 7.Work in pairs or in small groups. Share in the discussion. Use the following questions as prompts:
1) What does the term “metrology” mean? What is its origin?
2) What is fundamental metrology?
3) Could you give the definition of industrial metrology?
4) How can you describe legal metrology?
5) How does traceability correlate to metrology?
6) What institutions coordinate measurement standards?
7) What exact measurements do you know?
8) Is there any distinction between measurement error and mistakes in metrology?
9) What is the function of reproducibility and repeatability studies?
LESSON 8
LEVELING THE LEVEL
Lexical units:
dumpy level – нивелир, строительный уровень
surveying – геодезия
tripod – тренога, штатив
foot-screw = leveling screw – подъёмный винт
tape measure – рулетка, мерная лента
staff – нивелирная рейка
site survey – инженерно-геологические изыскания
benchmark – топографическая отметка уровня
arbitrary – произвольный, случайный
quadrant – четверть
traverse – пересечение
bubble level – пузырьковый уровень
tilting level – наклонный уровень
to flip – переворачивать
to hinge – подвешивать, устанавливать на шарнирах
to cancel out – уравновесить, сбалансировать
spirit level – ватерпас, уровень
swinging – качающийся
bar-coded – с нанесёнными отметками
graduation – деления на нивелирной рейке
to sweep – тянуть, проводить
level vial – ампула уровня
terrain – местность
to endure – продолжаться
despite – несмотря на
TEXT
A dumpy level, or a builder’s auto level, or a leveling instrument, or – now – an automatic level – all these synonyms are used to name just an optical instrument used in surveying and building to transfer, measure, or set horizontal levels.
The general principle of operations is as follows. The level instrument is set up on a tripod (a device used to support any one of a number of surveying instruments) and, depending on the type, either roughly or accurately set to a leveled condition using foot-screws (leveling screws). The operator looks through the eyepiece of the telescope while an assistant holds a tape measure or graduated staff vertical at the point under measurement. The instrument and staff are used to gather and transfer elevations (levels) during site surveys or building construction. Measurement generally starts from a benchmark with known height determined by a previous survey, or an arbitrary point with an assumed height.
A dumpy level is an older-style instrument that requires skilled use to set accurately. The instrument requires the level to be set in each quadrant to ensure it is accurate through a full 360˚ traverse. Some dumpy levels will have a bubble level ensuring an accurate level.
A variation on the dumpy and one that was often used by surveyors, where greater accuracy and error checking was required, is a tilting level. This instrument allows the telescope to be effectively flipped through 180˚, without rotating the head. The telescope is hinged to one side of the instrument’s axis. Flipping it involves lifting to the other side of the central axis (thereby inverting the telescope). This action effectively cancels out any errors introduced by poor setup procedure or errors in the instrument’s adjustment. As an example, the identical effect may be obtained with a standard builder’s level by rotating it through 180˚ and comparing the difference between spirit level bubble positions.
An automatic level, self-leveling level or builder’s auto level, includes an internal compensator mechanism (a swinging prism) that, when set close to level, automatically removes any remaining variation from level. This reduces the need to set the instrument truly level, as with a dumpy or tilting level. Self-leveling instruments are the very preferred instruments on building sites, construction and surveying due to ease of use and rapid setup time.
A digital electronic level is also set level on a tripod, and it reads a bar-coded staff using electronic laser methods. The height of the staff where the level beam crosses the staff is shown on a digital display. This type of level removes interpolation of graduation by a person, thus removing a source of error and increasing accuracy.
The very up-to-date laser level uses the laser beam projector that employs a rotating head with a mirror for sweeping the laser beam about a vertical axis. If the mirror is not self-leveling, it is provided with visually readable level vials and manually adjustable screws for orienting the projector. A staff carried by the operator is equipped with a movable sensor which can detect the laser beam and gives a signal when the sensor is in line with the beam – usually an audible beep. The position of the sensor on the graduated staff allows comparison of elevations between different points on the terrain.
In conclusion, it should be noted that the term “dumpy level” endures despite the evolution in its design.
Comprehension
Exercise 1.True or false?
1) An automatic level includes an internal compensator mechanism.
2) Scientists can’t understand the general principle of operations of a dumpy level.
3) There is no need to set the instrument truly level for an auto level.
4) A leveling instrument is an optical device used in surveying and building.
5) A tilting level uses the laser beam projector.
6) Digital electronic levels remove interpolation of graduation by a person.
7) Basically, a level instrument needs two persons to be operated.
8) Foot-screws are not the same things as leveling screws.
9) The instrument and staff are used to gather and transfer elevations, or levels.
10) There has been no evolution in the design of a dumpy level since its invention.
Exercise 2.Complete the sentences using the correct words from the text:
1) A … carried by the operator is equipped with a … sensor which can … the laser beam.
2) A … level allows the … to be effectively … through 180˚, without rotating the head.
3) The height of the … where the level … crosses the staff is shown on a digital ….
4) The … of the sensor on the … staff allows comparison of … between different points on the ….
5) … generally starts from a … with known height determined by a … survey.
6) A … is a device used to … any one of a number of … instruments.
7) Dumpy levels are …-… instruments that … skilled use to set ….
8) A movable … gives an … beep when it is in … with the laser beam.
Vocabulary
Exercise 3.Give the English or Russian equivalents for the following word combinations:
Местность, предназначенная для инженерно-геологических изысканий; preferred instrument on building sites; произвольное время установки ватерпаса; a visually readable level vial; установленный на шарнирах наклонный уровень; difference between spirit level bubble positions; необходимость сбалансирования качающегося прибора; hinged to the left side of the instrument’s axis; несмотря на продолжительные действия команды геодезистов; automatically adjustable screws for orienting the projector.
Exercise 4.Match the words with their meanings:
| 1) graduation | a) any means for the conversion or control of motion, or the transmission or control of power |
| 2) mechanism | b) a state in which opposing forces harmonize |
| 3) balance | c) a marking indicating a measurement |
| 4) accuracy | d) equipment designed for a particular purpose |
| 5) setup | e) freedom from mistakes; exact conformity to truth |
| 6) projector | f) optical device that projects a beam of light |
| 7) beam | g) the employees of a business or the workers of a plant |
| 8) staff | h) a ray or collection of parallel rays from any luminous body |
Exercise 5.Translate from Russian into English:
1) Нивелиром называется оптико-механический геодезический прибор для определения разности высот между несколькими точками. 2) У данного прибора есть зрительная труба, которая может вращаться в горизонтальной плоскости, и чувствительный уровень. 3) Современные оптические нивелиры оснащены автоматическим компенсатором, то есть устройством автоматической установки зрительной оси прибора в рабочее положение. 4) Если бы учёные не разработали лазерный нивелир, геодезические работы пришлось бы проводить как минимум двум специалистам. 5) Цифровые нивелиры обычно оборудованы запоминающим устройством, которое позволяет сохранять результаты наблюдений. 6) В промышленной геодезии метод геометрического нивелирования считается наиболее простым и точным. 7) Эффективность наклонного уровня при проведении измерений в гористой местности значительно снижается. 8) В лазерных уровнях используется принцип вращения лазерного луча, специально разработанный для этих электронно-механических приборов. 9) Как сообщили в новостях, высокоточный нивелир нового поколения сможет осуществлять измерения поверхностей различных планет, в первую очередь Луны и Марса. 10) С помощью элевационных винтов и подъёмного винта подставки можно быстро привести нивелир в рабочее положение.
Exercise 6.Make up the summary of the text and write its annotation.
Discussion
Exercise 7.Work in pairs or in small groups. Share in the discussion. Use the following questions as prompts:
1) What is a dumpy level? Give its analogous names.
2) Describe the general principle of its operation.
3) What are the main components of a level instrument?
4) What is the difference between a dumpy level and a tilting level?
5) Where can we find a swinging prism and what is it?
6) Why do specialists consider a digital electronic level to be the most dependable one?
7) How can you show the principle of work of a laser level?
8) What is the feature in the use of the term “dumpy level?”
9) What degree of precision can be obtained with the help of different types of level instruments?
FINAL TEST
Make the correct choice:
Variant 1
1. The precision of the laser rangefinder is determined by … .
a) the rise or fall time of the laser pulse b) the speed of the receiver
c) both of them d) sub-millimeter measurements
2. A digital electronic level always uses … .
a) a laser beam projector b) set level on a tripod
c) a bar-coded staff d) a telescope
3. A USB microscope is a … digital microscope.
a) multifunctional b) high-powered
c) transilluminating d) serviceable
4. The term “error” is used to describe … .
a) measurement uncertainty
b) measurement of an accepted constant
c) the absence of the quantity being measured
d) theoretical and practical aspects of measurement
5. Signal microcontrollers integrating analog components needed to control …, are common in the instrument-making industry.
a) industrial mechanical processes b) transporters and conveyers
c) digital computer systems d) non-digital electronic systems
6. Pressure sensors can be used to indirectly measure such variables as … .
a) intensity of a current b) time and date
c) speed, water level, and altitude d) sea depth and distances
7. The most common materials in sensors-making industry are … .
a) cast iron and aluminum b) polymers and metals
c) glass and silicon d) wood and plastics
8. In DSP, engineers study digital signals in one of the following domains: … .
a) time domain and frequency domain
b) spatial domain and autocorrelation domain
c) wavelet domains
d) in all of them
9. The integral part of each leveling instrument is a(n) … .
a) bubble level b) tripod
c) battery d) application-specific integrated circuit
10. Laser measuring tools usually include the ability … .
a) to produce some simple calculations
b) to calculate algebraic equations
c) to send the data obtained to the control station
d) to destroy themselves after their expiration date
11. The first microscope to be invented in the 16th century was the … microscope.
a) inverted b) optical
c) digital d) electromechanical
12. 1 degree Fahrenheit is the same as … .
a) 5/9 degrees Celsius b) 22 degrees Kelvin
c) 5 degrees Centigrade d) -243 degrees Kelvin
13. Microcontrollers must provide … response to events in the embedded system they are controlling.
a) very fast b) predictable
c) accurate d) logically grounded
14. The sensors used in a gas turbine are manufactured out of … materials.
a) bulletproof b) fusible
c) inflammable d) piezoelectric
15. A good sensor is … .
a) sensitive to the measured property only
b) sensitive to any other properties
c) designed to be non-linear to simple mathematical functions
d) able to react to any slight movement
16. Digital signal processing is often implemented … .
a) using special microcontrollers b) in many applied sciences
c) using specialised microprocessors d) as a part of nanotechnology
Variant 2
1. A laser rangefinder is a device which uses a … to determine the distance.
a) beam of electrons b) telescope
c) laser beam d) tape measure
2. USB and … are widely used by many modern manufacturing firms and labs.
a) stereo microscopes b) comparison microscopes
c) optical rangefinders d) digital microscopes
3. Today we can use … for digital signal processing.
a) general purpose microprocessors b) different optical devices
c) modern stereo systems d) industrial conveyors
4. A mirage may be caused by … .
a) the proximity to a desert b) temperature gradients in the air
c) personal hallucinations d) a powerful laser projector
5. The electron microscope is primarily used for … .
a) quality control b) failure analysis
c) both of them d) semiconductor device fabrication
6. Sometimes analog output signals require a(n) … .
a) analog-to-digital converter b) purpose-built hardware
c) magnetic resonance imaging d) digital-to-analog converter
7. We may find a visually readable … only in modern laser leveling instruments.
a) database b) tilting level
c) level vial d) magnet with specific qualities
8. Everybody may use a dumpy level in … and … to set horizontal levels.
a) outer space, vacuum b) building, surveying
c) designing, engineering d) fabrication, manufacturing
9. Metrology is the science that establishes the correctness of … .
a) specific measurement situations b) practical aspects of measurement
c) different scientific theories d) hard mechanical equipment
10. A … includes such parts as traceability, accuracy, precision, etc.
a) quality control system b) measurement standards system
c) quality management system d) governmental calibration committee
11. It is possible to convert … and … codes into a compact machine code.
a) English, Dutch
b) programming language, machine language
c) bar codes, digital
d) high-level language, assembler language
12. You may find … inside each tire.
a) the atmospheric pressure b) a nipple
c) an air-pump d) no pressure
13. A discrete Fourier transform produces the … information.
a) time and spatial b) frequency domain
c) algebraically proven d) frequency spectrum
14. All types of sensors have an impact on … .
a) living beings b) industrial processes
c) what they measure d) the environment
15. Microcontrollers are often used in … .
a) laser rangefinders b) automatic levels
c) automobile engine control systems d) optical microscopes
16. Pressure sensors are usually classified according to the … .
a) negative gauge pressure
b) application suitability and cost
c) difference between two or more pressures
d) temperature ranges of operation