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Sunday, 4 September 2022

Vernier scale

 A vernier scale, named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, thereby increasing resolution and reducing measurement uncertainty by using vernier acuity to reduce human estimation error. It may be found on many types of instrument measuring linear or angular quantities, but in particular on a vernier caliper which measures internal or external diameter of hollow cylinders and their lengths.


History

The first caliper with a secondary scale, which contributed extra precision, was invented in 1631 by French mathematician Pierre Vernier (1580–1637).[1] Its use was described in detail in English in Navigatio Britannica (1750) by mathematician and historian John Barrow.[2] While calipers are the most typical use of vernier scales today, they were originally developed for angle-measuring instruments such as astronomical quadrants.

In some languages, the vernier scale is called a nonius after Portuguese mathematician, cosmographer Pedro Nunes (Latin Petrus Nonius, 1502–1578). In English, this term was used until the end of the 18th century.[3] Nonius now refers to an earlier instrument that Nunes developed.

The name "vernier" was popularised by the French astronomer Jérôme Lalande (1732–1807) through his Traité d'astronomie (2 vols) (1764).[4]

Tuesday, 30 August 2022

History of Plus and Minus Sign

 Though the signs now seem as familiar as the alphabet or the Hindu-Arabic numerals, they are not of great antiquity. The Egyptian hieroglyphic sign for addition, for example, resembled a pair of legs walking in the direction in which the text was written (Egyptian could be written either from right to left or left to right), with the reverse sign indicating subtraction.



Nicole Oresme's manuscripts from the 14th century show what may be one of the earliest uses of + as a sign for plus.[3]

In early 15th century Europe, the letters "P" and "M" were generally used.[4][5] The symbols (P with overline, p̄, for più (more), i.e., plus, and M with overline, m̄, for meno (less), i.e., minus) appeared for the first time in Luca Pacioli's mathematics compendium, Summa de arithmetica, geometria, proportioni et proportionalità, first printed and published in Venice in 1494.[6]

The + sign is a simplification of the Latin: et (comparable to the evolution of the ampersand &).[7] The − may be derived from a tilde written over ⟨m⟩ when used to indicate subtraction; or it may come from a shorthand version of the letter ⟨m⟩ itself.[8]

A page from Johannes Widmann's book
From Johannes Widmann's book on "handy and pretty arithmetic for all merchants"[9][10]
In his 1489 treatise, Johannes Widmann referred to the symbols − and + as minus and mer (Modern German mehr; "more"): "[...] was − ist das ist minus [...] und das + das ist mer das zu addirst"[9][10][11] They weren't used for addition and subtraction in the treatise, but were used to indicate surplus and deficit; usage in the modern sense is attested in a 1518 book by Henricus Grammateus.[12][13]

Robert Recorde, the designer of the equals sign, introduced plus and minus to Britain in 1557 in The Whetstone of Witte:[14] "There be other 2 signes in often use of which the first is made thus + and betokeneth more: the other is thus made – and betokeneth lesse."

Plus and minus sign in Physics


In physics, the use of plus and minus signs for different electrical charges was introduced by Georg Christoph Lichtenberg.

In chemistry, superscripted plus and minus signs are used to indicate an ion with a positive or negative charge of 1 (e.g., NH+
4 ). If the charge is greater than 1, a number indicating the charge is written before the sign (as in SO2−
4 ). The minus sign is also used, in place of an en dash, for a single covalent bond between two atoms as in the skeletal formula.[citation needed]

In the International Phonetic Alphabet, subscripted plus and minus signs are used as diacritics to indicate advanced or retracted articulations of speech sounds.

The minus sign is also used as tone letter in the orthographies of Dan, Krumen, Karaboro, Mwan, Wan, Yaouré, Wè, Nyabwa and Godié.[22] The Unicode character used for the tone letter (U+02D7) is different from the mathematical minus sign.

The plus sign sometimes represents /ɨ/ in the orthography of Huichol.[23]

In the algebraic notation used to record games of chess, the plus sign + is used to denote a move that puts the opponent into check, while a double plus ++ is sometimes used to denote double check. Combinations of the plus and minus signs are used to evaluate a move (+/−, +/=, =/+, −/+).

In linguistics, a superscript plus + sometimes replaces the asterisk, which denotes unattested linguistic reconstruction.

In botanical names, a plus sign denotes graft-chimaera.

A plus sign written at the beginning of an international phone number is the "international prefix symbol" that "serves to remind the subscriber to dial the international prefix which differs from country to country and also serves to identify the number following as the international telephone number."[24]

ILAC IN NABL

 ILAC International Laboratory Accreditation Cooperation


In order, to enable global acceptance of its accredited Conformity Accreditation Bodies (CABs), NABL international bodies like Cooperation (ILAC) and Asia Pacific Accreditation CoInternational Laboratory operation (APAC).

 Accreditation NABL has obtained ILAC MRA for Reference Material Producers (RMP) accreditation program (ISO 17034) also, in addition to existing MRA in Testing (ISO/IEC 17025), Medical (ISO 15189 ), Calibration (ISO/IEC 17025) laboratories and Proficiency Testing Providers (PTP) accreditation program (ISO/IEC 17043). 

Such Mutual Recognition Arrangement (MRA) other MRA Partner accreditation systems. 

ILAC is the international organization  is based on peer evaluation and acceptance of ation for accreditation bodies op erating in accordance with ISO/IEC 17011 and involved in the accreditation of conformity assessment bodies including Testing Laboratories, Calibration Laboratories, Medical Testing Laboratories, Inspection Bodies and Proficiency Testing Providers. 

The Mutual recognition arrangements enhance the acceptance of products and services across national borders, thereby creating a framework to support international trade through the removal of technical barriers. For further details, kindly visit www.ilac.org

Thursday, 28 March 2019

Check Specific Gravity by Hydrometer only at just Rs 250




  • Material: Glass
  • Color: Clear
  • Product Dimension (B x H): 24 mm x 230 mm
  • Package Contents: 2 Hydrometer
  • Care Instructions: Handle with care

Specifications for this item
Brand NameAggarwal Crockery & Scientific Stores
ColourClear , Clear
Included Components2 Hydrometer
Material Typeglass
Number of Items2
Part NumberHydrometer1000-2000X2
Size230 mm
UNSPSC Code41110000

Hygrometer only on 250 rs minimum price,buy from this link get discount.




  • Wireless outdoor and indoor temperature (Fahrenheit or Celsius)
  • Measures temperature and humidity level
  • Includes clock, day, date and alarm function
  • Provides for flip out bracket for free standing or wall fixing
  • Batteries included

Specifications for this item
Brand NameHTC
ColourMulticolor
EAN0019007103904 , 0846619095255 , 0638370185999 , 0734026221957 , 0793518308477
Height2.49  centimeters
Item Weight150.0  grams
Length10.01  centimeters
Manufacturer Series NumberHTC-1
Material Typeplastic
Model NumberLCD DIGITAL TEMPERATURE HUMIDITY@@3
Number of Items1
Part NumberBFHTC-1
Specification Met
UNSPSC Code41113630
UPC793518308477 , 734026221957 , 846619095255 , 019007103904 , 638370185999
Width10.69  centimeters

"Sensor lights" Now feel more tech life like a iron man



  • Good solution for energy saving & easy in installation. & Delay adjustment: 10 Seconds - 7 Minutes & Adjustable Lux: turn on the lights during the day or night.
  • Using the automatic control product of infrared technology,when people walk into the sensor range,and the sensor can detect the spectral change of the human body infrared ray,during this time,the switch will connect the load automatically until the person leaves the sensor range. 2, Through the photosensitive control , it will not turn on the lights in the daytime or light environment, but also can be adjusted in any lighting environment sensing lights .
  • Sensitivity Adjustable: Turn On Lights during Day or nights.
  • It can use with lamps, incandescent lamps (bulbs), old-fashioned fluorescent lamps, electronic fluorescent ring lamps, spotlights, transformers, small electrical appliances, and other all other appliance.


  • Material:Plastic, Color:Black
  • Package Contents:20 LED Bright Outdoor Security Lights with Motion Sensor Light
  • Long working time and energy saving: Absorb sunlight for a few hours in daytime and it can light throughout the night. The light lasts for 8-10 hours if fully charged
  • Solar power lights: As winter approached the sunshine becomes weaker than summer, please make sure the item is put in direct sunlight all day so that it can absorb more sunlight for charging
  • Ultra-bright: 20 powerful leds and the motion angle is 120 degrees which can provide excellent illumination. It's a perfect choice to be used in garden, yard, driveway, stairs, outside wall etc
  • Waterproof and durable: This light is weatherproof and durable with solid hard plastic which can withstand years of usage
  • Solar panel life span: 5 years , led life span:50000 hours.Only takes 6-8 hours to fully charge

GET YOUR NEW REDMI HEADPHONE NOW!!!!! with Tangle free cable



  • Tangle free cable
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  • 3.5mm jack. Speaker impedance: 32Ω. Frequency Response Range: 20-20,000Hz, Rated power: 5mW
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Sunday, 24 March 2019

ISO/IEC 17025

ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories is the main ISO standard used by testing and calibration laboratories. In most countries, ISO/IEC 17025 is the standard for which most labs must hold accreditation in order to be deemed technically competent. In many cases, suppliers and regulatory authorities will not accept test or calibration results from a lab that is not accredited. Originally known as ISO/IEC Guide 25, ISO/IEC 17025 was initially issued by the International Organization for Standardization in 1999. There are many commonalities with the ISO 9000 standard, but ISO/IEC 17025 is more specific in requirements for competence and applies directly to those organizations that produce testing and calibration results and is based on somewhat more technical principles.[1]. Laboratories use ISO/IEC 17025 to implement a quality system aimed at improving their ability to consistently produce valid results.[2] It is also the basis for accreditation from an accreditation body.
There have been three releases; in 1999, 2005 and 2017. The most significant changes between the 1999 and 2005 release were a greater emphasis on the responsibilities of senior management, explicit requirements for continual improvement of the management system itself, and communication with the customer. It also aligned more closely with the 2000 version of ISO 9001 [3]
The 2005 version of the standard comprises five elements; Normative References, Terms and Definitions, Management Requirements, and Technical Requirements. Management requirements are primarily related to the operation and effectiveness of the quality management system within the laboratory. Technical requirements include factors that determine the correctness and reliability of the tests and calibrations performed in the laboratory.
The 2017 version of ISO/IEC 17025 has modified this structure to be Scope, Normative References, Terms and Definitions, General Requirements, Structural Requirements, Resource Requirements, Process Requirements, and Management System Requirements. General Requirements and Structural Requirements are related to the organization of the laboratory itself. Structure Requirements cite those issues related to the people, plant, and other organizations used by the laboratory to produce its technically valid results. Process Requirements are the heart of this version of the standard in describing the activities to ensure that results are based on accepted science and aimed at technical validity. Management System Requirements are those steps taken by the organization to give itself quality management system tools to support the work of its people in the production of technically valid results.


YOU CAN DOWNLOAD THE BOOKS OF ISO/IEC 2017 FROM HERE






CD-ROM IS ALSO AVAILABLE WITH FREE DELIVERY IF YOU BUY FROM THAT LINK.


Thursday, 4 October 2018

Tata Harrier

Tata Harrier UPDATE:
Latest update: Latest spy images of the Tata Harrier reveal its dashboard layout. It will get the floating touchscreen infotainment system that we've seen on the H5X Concept as well. Check out the spy images here.
The Harrier will be a five-seater SUV that will go on sale in India by April 2019. It is likely to be priced in the range of Rs 12 lakh to 18 lakh. So it will be a competition for SUVs like Hyundai Creta and Renault Duster on the one end and Jeep Compass on the other.
The Harrier is based on Tata Motor’s OMEGA (Optimal Modular Efficient Global Advanced) architecture and features its latest Impact 2.0 design philosophy. Under the hood, we expect the Harrier to be powered by the same 2.0-litre Multijet engine that powers the Jeep Compass. There is no clarity on whether it will be available with a petrol engine or not.

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Tata Harrier Rear Right Side Image
Tata Harrier Front Left Side Image
Tata Harrier Gear Shifter Image

Tata Harrier Steering Wheel Image

NEW MARUTI FUTURE S 2019

Maruti Suzuki Future S


EXPECTED PRICE 6 TO 7 LACS

MARUTI REVIEW ABOUT THIS CAR:
Maruti Suzuki, said, "Compact is the natural choice of India's car customers. Compact needs a fresh design language, one that is bold, confident and dynamic. Our designers have created this brand new design, aggressive on the outside, and bold and inviting interiors. Nothing like this has ever been attempted before on a vehicle this size. ConceptFutureS will define the next generation of design for compact vehicles in India".