ME - Mechanical Engineering


Online Magazine for Mechanical Engineers

A thermodynamic system is said to exist in state of thermodynamic equilibrium when no change in any macroscopic property is registered, if the system is isolated from its surroundings.
An isolated system always reaches in course of time a state of thermodynamic equilibrium and can never depart from its spontaneously.
Therefore, there can be no spontaneous change in any macroscopic property if the system exists in an equilibrium state.
A thermodynamic system will be in a state of thermodynamic equilibrium, if the system is the state of Mechanical equilibrium, Chemical equilibrium and Thermal equilibrium.
  1. Mechanical equilibrium: The criteria for Mechanical equilibrium is the equality of pressures.
  2. Chemical equilibrium: The criteria for Chemical equilibrium is the equality of chemical potentials.
  3. Thermal equilibrium: The criteria for Thermal equilibrium is the equality of temperatures.
Your are in a car, you want to fill the fuel tank of car by going to fuel filling station, you have no idea which side fuel tank is located. Then generally car driver try to get down of the car and find which side fuel tank is located.

But you can know fuel tank side of your car instantly without even stepping out of your car, by just looking at fuel meter on your dashboard.
Machines and gadgets have made our lives easy but one must understand they are subject to wear and tear and needs to be mended or replaced at some point of time. None can go on running till infinity. One such thing is the intercooler.
Basically an intercooler is nothing but an apparatus for cooling the gas subsequently over a series of successive compressions. This is an integral part in a car’s engine. Practically heat exchange takes place in many parts of the car’s engine and a nice intercooler can cool the fluid or gas during a multistage heating process. Hence, if you are looking to buy an intercooler, it is essential that you get to know certain things before actually possessing one. It is common sense that such elaborate automotive and mechanical engineering cannot be fully understood by us but there is certainly a lot we can do before buying.

Things that need to be considered
The primary thing that needs to be looked at is the flow capacity and efficiency. Price is also an important factor while buying. The flow can be easily checked by having a look at the airflow in both the directions through the core. This is probably the easiest check that can be done if one is looking forward to install such a unit in his vehicle.
Efficiency is quite difficult to predict without on the car testing. However one can have a look at the ratings provided by the manufacturer which may give an idea about the volume of heat exchange core and the solo of weight of the intercooler without any connections at all. The volume can give you an idea about the extent or amount of contact the hot air has with the cooling air. On the other hand the solo mass of the intercooler reveals the thermal mass of the material where heat air and charge can be transferred to. If your car travels a lot, without frequent traffic intervals, it is advisable to buy the one with greater mass since greater mass means greater heat-sinking ability.
However, mass is directly related with size and hence there can be size constraints depending upon the size of the engine bay. An alternative can be using water-to-air intercooler in such cases where there is not a little space available for an adequate flow. In this regard, one must also know that a small sized core can limit the potential of the turbo by trapping the charge air in it and not allowing it a path to flow.
If you are using water to air intercooler then the first and foremost thing that you should make a note of the water level frequently. In extreme cold weather when temperature goes beyond zero, antifreeze may be required. Since the water there may freeze completely it cannot function efficiently.
Last thing is maintenance and operational costs. One must ensure that these are minimal as far as possible since such things are nothing but an unnecessary burden on the owner. The water to air intercooler requires very less maintenance. Only those regular checks at the hoses and clamps are sufficient. A slight leakage in such type of an intercooler may be very woeful.
Lucid Pipe Overview
Portland, Oregon based has developed Lucid Pipe power system to generate electrical power from water flowing within the drinking water supply pipes that goes to homes, industries in cities and towns around the country.

Lucid Pipe Technology works on using wind energy principles. By installing huge size turbines inside water utility pipes, Lucid energy Inc. Generates electrical power using water flow through pipes. Turbines will produce electricity as long as water is flowing through the pipes.
One major benefit of the Lucid Energy system is that the conditions needed to create electricity are much more stable and predictable and for the most part highly controllable unlike the solar and wind power. There is no concern of disrupting aquatic animals inside a water utility pipe.
A single lucid pipe containing three or four turbines could generate electricity about 1,100 Megawatt-hours per year that could be sufficient for about 150 homes.

Water flows through Lucid Pipe’s lift-based turbine, generating electricity as the turbine rotates. The hydrodynamic turbine has been designed by Lucid Energy Inc. to maximize efficiency and electricity generation while limiting the onset of cavitation. As velocities of water flow inside pipe increase, electricity production increases. Due to the lift-based design of the Lucid Pipe turbine, the system generates power across a very wide range of velocities.

Below animation shows how Lucid Pipe Power System works

Source: Lucid Energy
A plate and frame heat exchanger (PHE) is often a preferred option because of excellent heat transfer capability. When using this type of unit, there are several critical factors that should be considered. For example, if the plate and frame heat exchanger will be used in conjunction with a cooling tower, the PHE must be designed specifically for the chemicals used as water treatment.

In addition, you will find it much easier and simpler to prevent leakage from occurring in the heat exchanger than from stopping the leak once it has begun. The most important step that you can take to ensure optimal operation is to make sure you work directly with the manufacturer. Obviously, the manufacturing company should have a solid history of excellence and unrivaled expertise specific to PHEs.

Brief Overview
A plate and frame heat exchanger is designed to use metal plates for transferring heat between two fluids. Compared to a more traditional heat exchanger, this type of system has a huge advantage in that fluids are exposed to a larger surface area since they are spread out over the plates. Because of this, the transfer of heat is better facilitated.

This also increases the speed of temperature change significantly. Today, a plate and frame heat exchanger is actually quite common. While there are small brazed versions used for residential purposes, large plate and frame heat exchangers for commercial or industrial use have a unique design of having gaskets in between the plates.

A plate and frame heat exchanger is used along with pipes and other types of containment vessels to heat and/or cool fluid via heat transfer between the first and a secondary fluid. Typically, the design includes a coiled pipe containing fluid that passes through a chamber with a second fluid. Additionally, the pipe walls are typically constructed from a high thermal conductivity material such as metal to help facilitate the interchange. On the larger chamber is an outer casing made from thermal insulation coated material or plastic that prevents the escape of heat.

Information to Provide Your Plate and Heat Exchanger Manufacturer

When requesting a quote, begin communicating all relevant details to the manufacturer. Because two liquid streams, known as the cold side and the hot side flow into and out of the heat exchanger, four different temperatures must be considered when determining the size of the heat exchanger. These temperatures include the hot side outlet, the hot side inlet, the cold side outlet, and the cold side inlet.

You also want to provide information so the heat exchanger can be properly sized such as flow rates, fluid names, outlet temperature, inlet temperature, maximum pressure drop, and operating pressures. Regardless if proprietary or uncommon fluids are used, you also need to provide the manufacturer with pertinent information pertaining to those fluids such as outlet temperatures, viscosity at inlet, specific gravity, thermal conductivity, and specific heat.

Sometimes, a manufacturer will ask for additional information in order to provide an accurate quote on the right type of plate and frame heat exchanger for your needs. To avoid delays, inaccurate bid, or the wrong plate and heat exchanger, be sure all information provided is accurate.
AVERT system lifts and moves car
European scientists developed AVERT (Autonomous Multi-Robot System for Vehicle Extraction and Transportation) Project for use of law enforcement.
A main robot that is able to map parking lot of a vehicle. This main robot controls four pair of smaller robots that are able to role under suspicious vehicle to access four wheels of a car.
AVERT Deployment unit which releases a Bogie pair
The increasing demand for basic commodities has driven up prices and spurred a global mining boom, but it is not an easy task to get them from mines because big layers of rock have to be moved first. Mw Hire Group made Infographic on heavy machines around the world that can make task easily.

Worlds Largest 5 diggers included in this infographic are:
  1. Bucyrus RH400 Hydraulic Shovel
  2. Takraf Bagger 293 Bucket-Wheel Evacuator
  3. Caterpillar 797F
  4. Metso Mobile Crusher
  5. Le Tourneau 2350
Washing Machine Treadmill named Wheel uses kinetic power to wash clothes. This washing machine will be beneficial for the people in urban areas. This innovative design wheel has been presented  by the Korean designer Si Hyeong Ryu at the Electrolux Design Lab 2014.
Electrolux Threadmill Washing Machine
Kinetic energy generated from this treadmill can be used to wash clothes and the unused energy can be used as electricity in the future.
The washing balls inside the treadmill reduces the washing time and quantity of needed water.
Washing Machine Treadmill wheel
Wheel has a flexible touch display and a solar panel made of Copper Indium Gallium Selenide (CIGS)  that substitutes the man power when it is not available.
The treadmill mechanism makes the environment friendly and helps the users for better workout experience for healthier life. The normal plug in and flexible display system inside the wheel provides let's the user to experience better running experience.
applications of Engineering and technology in fashion
Like many people say that Physics is everywhere, I would say that engineering is everywhere. Without the word “Engineering” nothing is complete. If you buy a simple needle from a store, you will find great work of engineering in that as well. This needle is just a tiny thing but when we talk about a big industry like fashion, there we find the different purpose of engineering. Researching deep about the connection between fashion and engineering, I found 5 things where it meets each other. But before that, let’s know more about engineering.
Engineering is the part of this world for a long time. Even when science wasn’t discovered, engineering was there in the form of wheel, wedge, lever and pulley. These engineering is the example of massive mind that human has and for modern world engineers, this is like a gift from God. These inventions push the world towards technology and to think beyond the things. Today we have everything and enjoying a comfortable life just because of science and engineering. So, it’s an important part of our life, and now it’s everywhere.
Coming back to the role of Engineering in Fashion Industry, let’s discuss the five major points where we can’t move forward without the help of technology. Here I will discuss these by talking leather fashion garment industry as an example.

Procedure of Design Creation:
design creation drawing
Before you go and make your product, you first have to design what you plan to make. You can’t do that just by hands; you will need some technology that will help you making the design perfectly. For example, when you think to make a leather garment, you have to decide what design you will work on computer software or perhaps sketch and after finalizing you will progress to manufacture process. So here, technology comes in the form of computer and worked.

Sterilizing/Cleaning Process
Sterlizing, cleaning process
When it comes to cleaning purpose it requires lots of safety and just can’t believe in yourself only, we have to take help and trust technology. What you will make people will consume it, and you have to make sure that you don’t provide any harmful thing to them. For example, before the unfinished leather progress for stitching and making, it’s sterilized with the help of machines and process well to kill all the bacteria and germs in it. Here, the technology works to make the material secure for the consumer.

Manufacturing and Finished Inventory
manufacturing and finished inventory
After cleaning and making garment secure enough to wear the process comes of shaping and finalizing it for the consumer. While, finalizing is a big process, but here I will explain it in three simple points where technology works. For example, after cleaning the material, next it comes to the dye process where chemistry works with engineering. Here the leather/material will get its color. After that the texture process starts. Talking about the leather, it comes in varieties of texture and all different process is need. Engineering and technology work with physics and chemistry to give you the final results at that point. Last process comes where the leather garment cuts into its shape and stitching process start. So like, from designing till making, it’s all technology and engineering working for the fashion industry but still there are more things coming.

Promotion Advertisement of Clothing
When the product is in its final shape, next comes selling it to the person looking for it. Now we just can’t wait till the customer comes to us. How would he know that we are building or making anything? We have to tell him and again its technology and engineering that will help us. For example, let take leather garment maker, as in today’s world, leather is one of the most consuming things all over the world and lots of people are there who are buying leather jackets online. The customer sees the advertisement that the seller have done to tell everyone what he makes and the conversion starts. Like this, lots of people prefer to use pamphlets to advertise, some use media advertisement to let people know about them. Without this, there will be no conversion between you and customer. So, technology also plays a significant role in this part of fashion industry.

Transport and Shipping Service
transport and shipping service
Here I’m talking about online stores that are increasing day by day. If anyone purchase anything online from your store then next what it comes for you is to deliver that stuff to the consumer. For example, in an online store of leather where people buy stuff from China to USA, it brings a long distance conversation that has to be covered. Now here, the technology works to deliver the thing from the seller to the customer, and this is the major part of the fashion industry as well.
So from the cleaning process till delivering it to customer technology helps. Today, our life is all dependent, and the modern engineering is still bringing new inventions to the world that can make our life easy to spend. If you have a small business or have massive factories, somehow somewhere you need technology for sure.
The sidewall of tyre provides the information about the tyre including the specifications, the brand, etc. All the codes on tyres are standardized and recognized by all tyre manufacturers worldwide
Tyre Specification
Meaning of codes marked on tyres:
  1. Tyre width (in mm)
  2. Aspect Ratio
  3. Rim Diameter (in inches)
  4. Load Index
  5. Speed rating
Specifications of tyre marked on sidewall on above image as 235/45R17 97W
The '235' indicates the section width of the tyre in millimeters.
The '45' tells the 'profile' of the tyre, or the width of the tyre compared to its height. It is expressed in percentage. (45%, in this case).
The 'R17' indicates the size (in inches) of the wheel rim to which the tyre is designed to be fitted.
The '97' indicates the tyre's load index, and
The 'W' denotes the speed rating.

Load Index:
Load index corresponds to the load capacity . Commonly chosen load index values of automobiles are shown below in image.
Tyre Load index table

Speed Rating:
The Speed rating of a tyre is the maximum speed at which the tyre can carry a load corresponding to its load index is an assigned letter ranging from J to Z that corresponds to the reference maximum speed at the associated load index. Refer to the speed rating table below.
Tyre Speed rating Table
If an object with a higher temperature comes in contact with an object of lower temperature, it will transfer heat to the lower temperature object. The objects will approach the same temperature and in the absence of loss to other objects, they will maintain a single constant temperature. Therefore, thermal equilibrium is attained.
The Thermodynamics Zeroth Law states that if two systems are at the same time in thermal equilibrium with a third system, they are in equilibrium with each other.
zeroth law of thermodynamics, three bodies are in equilibrium
If objects A and C are in thermal equilibrium with B, then object A is in thermal equilibrium with object C. Practically this means all three objects are at the same temperature and it forms the basis for comparison of temperatures.

The Zeroth Law of Thermodynamics states that:-
two system which are equal in temperature to a third system are equal in temperature to each other.
In Electric Discharge Machining process an arc is produced when two current-carrying wires are short-circuited. During this machining process, a small portion of metals is also eroded away, leaving a small cater. this phenomenon is used in electric discharge machining (EDM). EDM machining process is also known as spark erosion machining.
EDM involves a controlled erosion of electrically conductive materials by the initiation of electrically conductive materials by the initiation of rapid and repetitive spark discharges between the tool and workpiece separated by a small gap. Each electrical spark produces sufficient heat to melt a portion of the workpiece and usually, some of the tooling materials also. Due to rapid heating, the dielectric fluid evaporates in the arc gap which increases the resistance until the arc is interrupted. The associated shock wave and flowing dielectric fluid remove the gas bubbles which later collapse.
Schematic illustration of the electrical-discharge machining process
Electro chemical dissolution is based on the Faraday's laws, stated as follows:
The amount of electrochemical dissolution or deposition(m) is proportional to amount of charge (Q) passed.
The amount of material deposited or dissolved further depends on electrochemical equivalence (ECE) of the material, that is, the ratio of the atomic weight (A) and velocity (v).

Summary of EDM characteristics:

  • Mechanics of MRR: Melting and evaporation aided by cavitations (spark erosion).
  • Medium: Dielectric fluid (generally kerosene).
  • Tool material: Cu, Brass, Cu-W Alloy, Ag-W-Alloy, Graphite.
  • Wear Ratio: 0.1 to 10.
  • Maximum MRR: 5*10^3 ccmm/min.
  • Specific power consumption: 1.8 W/cc.mm/min.
  • Gap between work piece and tool: 10 to 125 ┬Ám.

Advantages:

  • L/D ratio as high as 20 can be achieved.
  • There is no contact between tool and workpiece so no forces acting in machining. So no residual stresses are generated in machining.
  • Out of all the unconvectional machining of methods, EDM is the one which gives highest MRR,
  • Melting and evaporation is the mechanism for chip formation, the mechanical properties of work piece material will not affect the material removal rate (MRR).
  • Surface finish produced will be better.

Disadvantages:

  • Used only for electrically conductive material.
  • Electrode wear is more.
  • Re-hardening occurs due to heat generated during machining.
  • Not possible to make exact square corners.

Applications:

  • Blind cavities and narrow slots in dies, minimum diameter hole can be produced is 0.13mm.
  • L/D ratio is as high as 20 can be done. So, due to this, EDM is particularly useful in machining of small holes, orifices, slots in diesel fuel injection nozzles, airbrake valves and aircraft engines etc.