Mechanical Inventions

Below tables shows list of 112 Mechanical Inventions arranged in the order of invented year with inventor(s) name and inventor country they belong to.

If you want us to include any more Mechanical Inventions comment below.

First Law of Thermodynamics

The First Law of Thermodynamics states that energy is neither created nor destroyed, thus the total energy of the universe is a constant. However, energy can certainly be transferred from one form to another form.

The 1st Law of thermodynamics is mathematically stated as follows:

§dQ = §dW

During a thermodynamic cycle, a cyclic process the systems undergoes, the cyclic integral of heat added is equal to integral of work done. the first law equation can also be written in the form,

§(dQ – dW) = 0

Equation dU = dQ - dW is corollary for first law of thermodynamics. It shows that there exists a property internal energy (U) of the system, such that a change in its value is equal to the difference in heat entering and work leaving the system.

Sign convention for heat and work in  first law of thermodynamics is represented in picture below.

Another property named enthalpy (H) can also be defined now as a combination of properties U, p and V.

H = U + pV

For a reversible process, since dW = pdV, the first law of thermodynamics can also be written as

dQ = dU + pdV

Properties of Fluids

Understanding the properties of fluids is essential to analyse their behavior in working conditions.

In this post I have written the fluid properties namely mass density, specific weight, specific volume, specific gravity, viscosity, vapor pressure, compressibility and surface tension.

Mass Density:

Mass Density (ρ) is the property of a fluid is the mass per unit volume.

Specific Weight:

Specific Weight (w) of a fluid is the weight per unit volume.

Specific Volume:

Specific Volume (v) of a fluid is the volume of the fluid per unit mass.

Specific Gravity or Relative Density:

Specific Gravity (s) of a fluid is the ratio of the mass density of a fluid to the mass density of a standard fluid.

Viscosity:

Viscosity is property by virtue of which it offers resistance to the movement of one layer of fluid over the adjacent layer.

Vapor Pressure:

When a liquid is confined in a closed vessel, the ejected vapor molecules accumulated in the space between free liquid pressure and top of the vessel exert a partial pressure on the liquid surface. This pressure in liquid is known as vapor pressure.

Compressibility:

The normal compressive stress of any fluid element at rest is known as hydro static pressure which arises as a result of innumerable molecular collisions in the entire fluid. The degree of compressibility of a substance is characterized by bulk modulus of elasticity (K).

Surface Tension:

Surface is a measure of fluid tendency to take a spherical shape, caused by mutual attraction of the liquid molecules.

15 most Popular Car Manufacturing companies

In this post We have written the top 15 most Popular automobile car manufacturing companies. We have given ranking to automobile companies by considering number of followers to company in social media. Social media that we have considered are google+, twitter and facebook. Calculation of number of followers is made on basis of calculating sum of total followers in facebook, google+ and twitter . Only the company's worldwide social accounts are considered (Regional social media accounts are not considered while making this analysis). If the company doesn't have worldwide account, USA accounts are considered for making analysis.

15. Volkswagen Group

Volkswagen is an German automobile manufacturer. Volkswagen group products are Automobiles, commercial vehicles, engines, motorcycles, turbomachinery. Vw stands 15th position in social media followers.

14. Mitsubishi

Mitsubishi is an autonomous Japanese multinational companies. Mitsubishi products are Mining, shipbuilding, telecom, financial services, insurance, electronics, automotive, construction, heavy industries, real estate, foods and beverages, chemicals, steel.etc. This company stands 14th position in social media followers with 2,299,000 fans as on 15th August.

13. Mazda

Mazda Motor Corporation is a Japanese automobile company. Mazda manufactures luxury vehicles, commercial vehicles, engines and motorcycles. It has 2720k fans with thirteenth position.

12. Toyota

Toyota is a Japanese Automotive Manufacturer. Toyota Motor Corporation manufactures luxury vehicles, commercial vehicles, engines and motorcycles. Toyota has 2771k fans on three social media.

11. Chrysler

Chrysler is an American Automobile Manufacturer owned by Italian company Fiat. Chrysler manufactures Commercial vehicles and Automotive parts. Chrysler and GM have nearly same number of followers in social media.

10. General Motors

General Motors is known as GM. It is an American Multinational corporation. General Motors manufactures are Automobile parts Commercial Vehicles. GM couldn't be successful in getting followers from facebook it stands 10th position with 2883k  fans.

9. Fiat

Fiat is the main Italian car manufacturer, founded in 1900. It owns the company Chrysler. Fiat products are Automobiles, commercial vehicles, auto parts, newspapers. Fiat company has 30 lakh followers in social media which makes it to stand in ninth position.

8. Honda

Honda Motor Company Ltd. is a Japanese company famously known as a manufacturer of automobiles, motorcycles and power equipment. Honda is the world largest two wheeler manufacture from the past 50 years. Honda has nearly 40 lakh fans.

7. Hyundai

Hyundai Group is a multinational chaebol headquartered in Seoul, South Korea. Honda was founded in 1947 as a construction. Hyundai products are Automobiles, Heavy industry, Finance and Insurance, Construction, Engineering, Retail, Aerospace, Defense and Steel. Hyundai has good number of fans in social media which sums up to 4,411,000 including facebook, google+, twitter.

6. Kia

Kia Motors Corporation is South Korea's second-largest automobile manufacturer. Kia's products are automobiles, Luxury cars and Commercial vehicles. It stands sixth in position in social media following with around 5 billion followers.

5. Ford Motor

Ford Motor company is an American multinational Automaker. Ford Motor Company Automobile products are Luxury Vehicles Commercial Vehicles Automotive parts. Ford stands fifth in social media fans with 4,988,000 followers.

4. Audi

Audi is a German automobile manufacturer that designs, engineers, produces, markets and distributes automobiles. Audi manufactures only luxury cars. It has clear leader on twitter with 810,000 fans, with overall 11,667,000 fans.

3. Nissan Group

Nissan Group products are Industrial machinery, telecommunications, power plants, information systems, electronics, automotive, materials, financial services, construction. It is third position with 13,791,000 followers.

2. Mercedes-Benz

Mercedes-Benz is a German automobile manufacturer, a multinational division of the German manufacturer Daimler AG. Mercedes-Benz is used for luxury automobiles, buses, coaches and trucks. Benz stands second in social network with 19,857,000 fans.

1. BMW Group

BMW (Bayerische Motoren Werke AG) is a German automobile company. BMW products are luxury vehicles, motorcycles and bicycles.

It stands first position in the social media with 23,276,000 followers.








Below table shows the social media fans count to top 15 automobile manufacturing companies.

There is no positive correlation between increase in sales and increase in social media fans.
All these data were collected on August 15th, 2014.

Temperature conversion from one scale to another scale

A temperature scale is established by assigning numerical values to certain reproducible states. It is customary to use the fixed points ice point and steam point.

Ice point is the equilibrium temperature of ice with air-saturated water at a pressure of 101.325 kPa which assigned a value of 0 degree centigrade.

Steam point is the equilibrium temperature of pure water with its own vapor at 101.325 kPa which is assigned a value of 100 deg C.

The temperature scale with the above fixed points is called Celsius scale.

Relationship between different temperature scales

Where,

LPF = Lower Fixed Point,

UPF = Upper Fixed Point.

F = Fahrenhiet scale,

C = Centigrade scale,
K = Kelvin scale

R = Reaumer’s scale,

ρ = Our defined scale,

Below I have given the program for converting temperature from one scale to another scale. Write the value of any one scale and then press 'Calculate' then you will get corresponding values in the remaining scales.

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Temperature Scale Converter

Fahrenheit Scale(F): 
Celsius Scale (C): 
Reaumer Scale (R): 
Kelvin Scale (K): 

    

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Differences between Welding, Soldering and Brazing

Welding, Soldering and Brazing are the process used for joining separate pieces of metal. Each type of joining process has its own significance. Type of joining process to be used depends on many factors. In this article I have written the three major differences the welding, soldering and brazing joints.

S.No	Welding	Soldering	Brazing
1	Welding joints are strongest joints used to bear the load. Strength of the welded portion of joint is usually more than the strength of base metal.	Soldering joints are weakest joints out of three. Not meant to bear the load. Use to make electrical contacts generally.	Brazing are weaker than welding joints but stronger than soldering joints. This can be used to bear the load up to some extent.
2	Temperature required is 3800 degree Centigrade in Welding joints.	Temperature requirement is up to 450 degree Centigrade in Soldering joints.	Temperature may go to 600 degree Centigrade in Brazing joints.
3	Work piece to be joined need to be heated till their melting point.	Heating of the work pieces is not required	Work pieces are heated but below their melting point.

Wein's Displacement Law

The Wien's Displacement Law states that a black body having a wavelength (λ_max) carrying the maximum energy is inversely proportional to the absolute temperature (T).

λmax * T = b

Where, λmax  =  Wavelength of maximum intensity in meters,

T  =  Temperature of the black body in kelvins,

b  = Wien's displacement constant  =  2.898 × 10^(-3) meter.kelvins

Image Credits : Hyperphysics

Wien's Displacement law equation is useful for the find the temperatures of hot radiant bodies such as stars and used for a finding of the temperature of any radiant object which is far above that of its surroundings.

Log Mean Temperature Difference (LMTD)

The LMTD is a logarithmic average of the temperature difference between the hot and cold fluid streams at each end of the heat exchanger. The larger the value of LMTD, the higher heat is transferred.

The rate of heat transfer can be expressed as q = U*A*ΔT_m

_{Where ∆Tm is the log mean temperature difference given as}

Parallel Flow Heat Exchanger

Counter Flow Heat Exchanger

Assumptions made in LMTD method are

• The Internal Energy (U) is constant throughout the Heat Energy
• Cp and m are constant.
• The Heat Exchanger is perfectly insulated
• The Cross Section of stream is uniform
• No conduction of heat along the tubes of Heat Exchanger
• The Kinetic Energy and Potential Energy changes are negligible
• The flow conditions are steady