Units

 Units

All engineered systems require measurements to chararcterise an object's performance as well as to determine its size, weight, speed, etc. It's important to comprehend how to use these units.

the single most significant goal of this book because it pertains to every aspect of engineering and everything an engineer performs. Understanding units involves much more than just being able to convert between feet and meters or the other way around; integrating and converting units from many sources is a difficult subject. Combining and converting units from several sources is a difficult problem. For example, meters to meters or vice versa. How may thermal conductivity, measured in Watts per meter per degree Celsius, be converted from, for instance, building insulation defined in BTU inches per hour per square foot per degree Fahrenheit? Or is it convertible? Are the measurements made by the two units equivalent or not? (For instance, the natural gas flow was insufficient in a new engine laboratory facility that was being constructed for me. In order to produce a minimum of 50 cubic feet per minute (cfm) of natural gas at a pressure of 5 pounds per square inch, I informed the contractor that I needed a system (psi). What is the conversion between cfm and psi, he asked in response. Naturally, the answer is "no," as cfm and psi are measurements of flow rate and pressure, respectively.) These myths present a daily challenge for engineers.

The USCS (US Customary System) and the English systems of units and measurements are burdensome for American engineers! and (2) the SI ( Saystem International d' Unités) metric system. Both systems have a set of base units, which are created based on a standard measure such the quantity of wavelengths produced by a specific light source. These fundamental units comprise:

👉Length (meters, centimeter, feet, inches); 1 m = 100 cm = 3.281 ft = 39.37 in

👉Mass ( l bm, slugs, kilograms); (1 kg = 2.205 l bm = 0.06853 slug) ( l bm = "pounds mass")

👉Time (seconds; the standard contraction is "s" not "sec") (same units in USCS and SI!)

👉Electric flow (truly electric charge in units of coulombs [abbreviation: 'coul' is the base

     unit and the determined unit is current = charge/time) (1 coulomb = charge on 6.241506 x 1018

     electrons) (1 ampere [abbreviation: amp]= 1 coul/s)

In spite of frequent reports to the contrary, moles are only an accounting convenience used to avoid lugging around factors of 10^23 everywhere. The number of particles in a mole of particles is wholly arbitrary; by convention, Avogadro's number is given as NA = 6.0221415 x 10^23, with particles/mole (or persons of any sort, not only particles) serving as the unit of measurement.

Temperature is frequently used as a base unit, although it is not; rather, it is a derived unit, which means that it was produced by combining foundation units. In essence, temperature is a unit of energy multiplied by Boltzman's constant. An ideal gas molecule's average kinetic energy in a three-dimensional box is 1.5kT, where k is Boltzman's constant, which is 1.380622 x 10^-23 J/K (actually (Joules/molecule)/K). The kinetic energy of an ideal gas molecule (and only an ideal gas; no other substance) is 1.5 kT = 2.0709 x 10^-23 J at 1 Kelvin, which is the temperature at which this occurs.

The ideal gas constant (ℜ) with which are you are very familiar is simply Boltzman’s constant multiplied by Avogadro’s number, i.e. 

There’s also another type of gas constant R = ℜ/M, where M = molecular mass of the gas; R depends on the type of gas whereas ℜ is the “universal” gas constant

What is Mechanical Engineering

What is Mechanical Engineering? 

A mechanical engineer will handle it if it needs engineering but doesn't involve electrons, chemical reactions, the arrangement of molecules, living forms, isn't a structure (building, bridge, dam), and doesn't fly.

Mechanical engineers may handle it regardless if it involves electrons, chemical events, molecule arrangements, life forms, is a structure, or flies.

Although every engineering professor in every engineering department will assert that his or her specialty is the broadest engineering discipline, this is actually true for mechanical engineering because the core concepts are present in all engineering systems (fluid mechanics, solid mechanics, heat transfer, control systems, etc.).

Although being one of the oldest engineering specialties (though possibly Civil Engineering is even older), Mechanical Engineering has seen a quite dramatic transition during the past 20 years as a result of various new technology advances,  

• Computer Aided Design (CAD)

The typical non-technical individual may believe that mechanical engineers create drawings for tools with nuts, bolts, shafts, gears, bearings, levers, etc. while seated in front of a drafting table. The drafting board has long since been superseded by CAD software, which allows a part to be built and tested digitally before any real object is made, despite the fact that the depiction was partially accurate one hundred years ago.

Simulation.

Before committing to manufacture, CAD enables for testing the resulting virtual parts for structural, thermal, electrical, aerodynamic, and other factors as well as sizing and verifying for fit and interferences.

Sensor and actuators. 

These days, even everyday consumer goods like cars include dozens of sensors to detect things like temperatures, pressures, flow rates, linear speeds, and rotational speeds. These sensors serve as inputs to a microcontroller in addition to being utilished to monitor the device's health and performance. The microprocessor in turn controls actuators that modify valve positions, timings, and flow rates (such as the amount of fuel injected into an engine).

3D printing. 

Starting with a block or casting of material, traditional "subtractive manufacturing" involved removing material by drilling, milling, grinding, etc. But compared to contemporary "additive manufacturing" or "3D printing," which builds a structure in layers, the shapes that can be made in this technique are constrained. A new method of producing prototypes and, in some circumstances, full-scale manufacturing has emerged as a result of 3D printing, much to how CAD + simulation led to a new way of designing systems.

Collaboration with other fields.

An automobile, for example, was historically designed almost entirely by mechanical engineers. Large electrical and electronic systems, safety features like air bags and seat belts, and specialised batteries are all present in modern vehicles. etc., which, respectively, call for design input from electrical, biomechanical, and chemical experts. A modern mechanical engineer must be able to comprehend and take into account the demands that non-mechanical considerations place on the system.

Mechanical engineering is both tough and intriguing because of the drastic changes in what they accomplish today compared to a relatively recent time.

Mechanical Engineering curriculum

In almost any accredited Mechanical Engineering program, the following courses are required:

👉Essential sciences - math, science, physical science

👉Broadness or conveyance (called "General Training" at USC)

👉PC illustrations and PC helped plan

👉Exploratory designing and instrumentation

👉Mechanical plan - nuts, screws, gears, welds

👉Computational methods - converting continuous mathematical equations into discrete equations for        example

👉Core “engineering science”

         ⇛Elements - basically F = mama applied to many kinds of frameworks

         ⇛ Strength and properties of materials

         ⇛Liquid mechanics

         ⇛Thermodynamics

         ⇛Intensity move

         ⇛Control frameworks

👉Senior "capstone" plan project

Examples of industries employing MEs

Numerous businesses utilize mechanical designers; a couple of ventures and the kind of frameworks MEs

configuration are recorded underneath.

💥Automotive 

    🧿Ignition

    🧿Motors, transmissions

    🧿Suspensions

💥Aviation (w/plane design specialists)

    🧿Control frameworks

    🧿Heat move in turbines

    🧿Liquid mechanics (inner and outer)

💥Biomedical (w/doctors)

     🧿Biomechanics - prosthesis

     🧿Stream and transport in vivo

💥PCs (w/PC engineers)

     🧿Heat move

     🧿Bundling of parts and frameworks

💥Development (w/structural specialists)

    🧿Warming, ventilation, cooling (central air)

    🧿Stress examination

💥Electrical power age (w/electrical architects)

    🧿Steam power cycles - intensity and work

    🧿Mechanical plan of turbines, generators, ...

💥Petrochemicals (w/substance, oil engineers)

    🧿Oil boring - stress, liquid stream, structures

    🧿 Plan of treatment facilities - channeling, pressure vessels

💥Mechanical technology (w/electrical designers)

    🧿Mechanical plan of actuators, sensors

    🧿Stress investigation

TRACTION

TRACTION

HISTORY OF ELECTRIC TRACTION :-

👉 4500-3300 BC (Copper Age): creation of the potter's wheel; earliest strong

      wooden wheels (circles with an opening for the hub); earliest wheeled

      vehicles; training of the pony

👉 2200-1550 BC (Center Bronze Age): creation of the spoked haggle

       the chariot

👉  In 1769 the primary steam-controlled vehicle equipped for human transportation

       was worked by Nicolas-Joseph Cugnot.

👉 In 1803, Hayden Wischett planned the main vehicle controlled by the de Rivaz

      motor, an early gas powered motor that was filled by hydrogen.

👉 Marcus made the two-cycle burning motor.

👉 The vehicle's second manifestation in 1880 presented a four-cycle, gasolinepowered motor, a                   cunning carburetor plan and magneto start. He made two extra models further refining his plan               with guiding, a grasp and a brake.

 

👉  Development of the gas (petroleum ) energized gas powered motor in the 1880s.

👉 The four-stroke petroleum gas powered motor that actually comprises the

      most predominant type of present day car drive was protected by Nicolaus Otto.

👉 The comparative four-stroke diesel motor was imagined by Rudolf Diesel.

👉 1803 - First open railroad was made in London. It moved products through strength on the line that          was 14 km long.

👉  1804 - British chap Matthew Murray made first steam based train in Leeds.

👉 1812 - First business traveler rail line opens in Britain on the Middleton Rail line.

👉 The battery electric vehicle owes its starting points to Ányos Jedlik, one of the  innovators of the             electric engine, and Gaston Planté, who designed the lead-corrosive battery in 1859.

👉  In1881 First open electric cable car line opened in Berlin.

👉 In 1882 the Italian Enrico Bernardi made the principal petroleum controlled vehicle, a

       tricycle.

👉 1890 - London underground trains changed to electrical motors, beginning the

        time of present day quick travel frameworks.

👉 1913 - Diesel fueled trains began being utilized in Sweden.

👉 1937 - German innovator Hermann Kemper licensed train framework that utilized

       attractive levitation (maglev).

VARIOUS SYSTEMS OF TRACTION

💥Traction is the activity of drawing or pulling something over a surface,

     particularly a street or track.

💥"a crude vehicle utilized in creature footing"

💥Rationale power gave to draw or pull something, particularly on a railroad.

      Drive of vehicle is known as the foothold and the framework that causes the

       impetus of a vehicle in which that main thrust or tractive power is

       gotten from different power and gadgets, for example, Muscle power driven Foothold

       frameworks, electric engines, steam motor drives, petroleum motor drives, diesel

        motor jumps, Battery controlled drives, Attractive levitation and so on. Is known as

        foothold framework.

IDEAL TRACTION SYSTEM

💢Traction High beginning tractive exertion to have quick speed increase.

💢Independent and smaller train so it very well might have the option to run on any

      defeat.

💢 Hardware fit for enduring huge transitory over-burdens.

💢Least wear on the track.

💢Slowing down ought to be to such an extent that base wear is caused on the brake shoes, and

      assuming that conceivable the energy ought to be recovered and gotten back to the inventory.

💢Hardware required ought to be least, high proficiency, low starting and

      support cost.

💢 No impedance to the correspondence line running along the track.

💢 Simple speed control.

💢 It ought to be without contamination.

DIFFERENT SYSTEM OF TRACTION

🧿Traction Systems using muscles Power : 

    🎯Animal driven : Bullock cart , Horse cart , Sledge etc.

     🎯Manual driven : Cycle, Rickshaw, cycle van etc. 

🧿Traction systems using motive power: 

   🎯Non-electric Traction System 

    🎯Direct Steam Engine Drive 

    🎯Direct Internal Combustion Engine Drive

🧿 Electric Traction System 

       🎯Steam Electric Drive 

        🎯Internal Combustion Engine Electric Drive 

                             ● Diesel electric traction 

                             ● Petrol electric traction 

        🎯Battery Electric Drive 

        🎯Electric Traction Drive 

        🎯Electro-Magnetic levitation system.