Different types of forces

There are different types of forces that act in different ways on structures such as bridges, chairs, buildings, in fact any structure. The main examples of forces are shown below. Study the diagram and text and then draw a diagram/ pictogram to represent each of these forces. 

A Static Load : A good example of this is a person seen on the left. He is holding a stack of books on his back but he is not moving. The force downwards is STATIC.
A Dynamic Load : A good example of a dynamic load is the person on the right. He is carrying a
weight of books but walking. The force is moving or DYNAMIC.

DYNAMIC LOAD (moving)                                     STATIC LOAD (standing still)

 

Internal Resistance : The person in the diagram is sat on the mono-bicycle and the air filled tyre is under great pressure. The air pressure inside it pushes back against his/her weight. 

INTERNAL RESISTANCE

Tension : The rope is in "tension" as the two people
pull on it. This stretching puts the rope in tension. 

TENSION

Compression : The weight lifter finds that his body
is compressed by the weights he is holding above
his head.

COMPRESSION

 

 Shear Force : A good example of shear force is
seen with a simple scissors. The two handles put
force in different directions on the pin that holds the
two parts together. The force applied to the pin is
called shear force.

                                                                                 SHEAR FORCE

 Torsion : The plastic ruler is twisted between both hands. The ruler is said to be in a state of torsion.
                                                              TORSION

Classifications of FluidTypes of Fluids, Fluids,

Source: Uzochukwu Mike
What are types of Fluids?
Of what types/classifications are fluids in science and engineering study? What do you think is the definition of fluid? Fluids can be defined as substances that flow or deform under the application of shear stress, and these include liquids and gases. They are part of engineering study in many tertiary institutions of the world.
Basically, in the study of science, fluids are divided into two broad groups. These divisions in this write-up are known as types of fluids which are Newtonian and non- Newtonian fluids. Newtonian
fluids are those fluids that obey Newton Law of viscosity. Non-Newtonian fluids are the opposite of
Newtonian fluid in the sense that they do not obey Newton Law of viscosity. Non Newtonian fluids in this text are sub-divided into time-independent, time-dependent and elasticoviscous or viscoelastic
fluids.
Newtonian Fluids
What are Newtonian fluids. Newtonian fluids as written in the introductory part of this text are those fluids that concur (agree) with the Newton Law of viscosity. Viscosity is the opposition to the flow of fluids and it is measured in force per unit area of the fluid. The generally accepted unit of viscosity is Newton per meter square (NM -2 ). This is known as the SI unit of viscosity which is the same with that of stress.
Mathematically, viscosity is expressed as Force per unit area or simply F ̸̸ A. Newton law of viscosity
states that the shear stress on a fluid element layer is directly proportional to the rate of shear strain. In Newtonian fluids, coefficient of viscosity does not change with the rate of deformation of the fluid.
Examples of Newtonian fluids are: water, kerosene and air.It is shown mathematically as: τ = ηγ; where τ = shear stress, η and γ are coefficient of viscosity and share strain respectively.
Non- Newtonian Fluids
What are Non-Newtonian fluids and their classifications?
Non-Newtonian fluids are those fluids that do not obey Newton’s Law. They are the opposite of Newtonian fluids. Examples of non-Newtonian fluids are colloids, emulsions, pastes, sols, gels, thick
slurry, latex-based paints, and Biological fluids. Note that non-Newtonian fluids are many but these are few examples given. Non-Newtonian fluids do not exhibit the property of Newtonian fluids where
shear stress is directly proportional to shear rate.
There are three broad classifications of non- Newtonian fluids. These three classifications are: time-independent, time-dependent and viscoelastic fluids. The viscoelastic fluids can also be called
elasticoviscous fluids. One should not be confused because some textbooks relating to fluids may only one of these two names. Notwithstanding the three broad classifications of non-Newtonian fluids, there are also some other divisions of the three.
Time-Independent Fluids
As the name sounds, time-independent fluids are those non-Newtonian fluids that do not depend on time. They are those fluids in which the shear rate at a given point is a function of stress at that point
only. Examples of time-independent fluids are Casson, Bingham, Dilatent and Pseudoplastic fluid.
The Bingham fluid as an exampleof time-independent fluid does not flow at all until the shear stress exceeds certain critical value called yield stress. In this fluid, the flow behaviors appear like that of Newtonian once the system begins to flow. There is an internal structure in this type of fluid which breaks down before flow of the fluid can start. Notable examples of Bingham fluids are tomato puree, wood pulp suspensions, butter, drilling mud and toothpaste. When equation is used to represent Bingham fluid, it is represented as: τ = τ y + ƞγ , where τ y is yield stress.
Casson fluids also require a critical shear stress to overcome before flow can occur in the system. The
type of flow in this type of time-independent fluid is non-Newtonian, non-linear and parabolic in shape.
Casson and Bingham fluids are called plastic fluids.
Dilatent and Pseudoplastic fluids exhibit different characters on their own. Dilatent fluid is also called
shear thickening fluid. Dilatant fluid becomes more viscous as the shear stress increases. The shear stress increases much more rapidly than the shear rate in this kind of fluid. Examples of dilatent fluids are slurry and highly concentrated suspensions, like, Poly Vinyl Chloride. Pseudoplastic fluid is opposite to Dilatent fluid because the share rate increases much more rapidly than the shear stress.
It is known as shear thinning fluid. As the shear stress increases, pseudoplastic fluid becomes less viscous.
Time-Dependent Fluids
Time-dependent fluids are fluids whose shear rate is a function of shear stress and time. In this type of non-Newtonian fluid, the property of the fluid flow such as apparent viscosity changes with time. It is further classified into thixotropic and rheopectic fluid. In relation of thixotropic with rheopectic fluids, if the shear stress and shear strain relationship are observed with increasing shear rate, both sets of data do not coincide. This results to formation of hysteresis loop. In thixotropic and rheopectic fluids, at a given shear rate; there are two apparent viscosities depending on when the readings were
taken. The difference between the two is that thixotropic fluid becomes less viscous on application of stress while rheopectic fluid becomes more viscous on application of stress.
Elasticoviscous Fluids
Fluids that are predominantly viscous but show partial elastic recovery after deformation are termed elasticoviscous fluids. Examples of such fluids are multi-grade oils, polymer melts and liquid detergents. The term viscoelastic fluid is also used in place of elasticoviscous fluids as the former denotes solids with viscous properties while the later (elasticoviscous) denotes fluids that possess elastic property.
Conclusion
In summary, this write-up has dealt seriously on types of fluids based on science and engineering study. Fluids cannot be done without in our everyday life and this is one of the reasons that makes scientists to show more interesting in categorizing them and for more in-depth study of their flow. One of the basic types of food which people neglect is fluid. Do you know what that important fluid is? It is no other thing but the water we drink on our daily basis and I do not think you can do without it. Gasoline is another basic fluid used in automobiles and this is of great help to man. We cannot be able to power or motors on without this energy supplier. So, respect is to be given to fluids as they contribute to both technological and human development. Fluids were categorized broadly as Newtonian and Newtonian fluids. The non-Newtonian fluids were further divided into other classes and explained in sub-headings.
References
Fluid Mechanics by R.K Rajput;
Introduction to Polymer Technology by Dr. E. M. Katchy.

Classification of Automobiles

An automobile is a vehicle that is capable of propelling itself. Since 17th century, several attempts have been made to design and construct a practically operative automobile. Today, automobiles play crucial role in the social, economic and industrial growth of any country.
After the designing of Internal Combustion Engines, the Automobile industries has seen a tremendous growth.

Classification of Automobiles:
Automobiles can be classified into several types based on many criteria. A brief classification of automobiles is listed below:
1. Based on Purpose :
Passenger vehicles : These vehicles carry passengers. e.g: Buses, Cars, passenger trains.
Goods vehicles: These vehicles carry goods from one place to another place. e.g: Goods lorry, Goods carrier.
Special Purpose : These vehicles include Ambulance, Fire engines, Army Vehicles.
2. Based on Load Capacity: Light duty vehicle : Small motor vehicles. eg: Car, jeep, Scooter, motor cycle
Heavy duty vehicle: large and bulky motor vehicles. e.g: Bus, Truck, Tractor
3. Based on fuel used:
Petrol engine vehicles : Automobiles powered by petrol engine. e.g: scooters, cars, motorcycles.
Diesel engine vehicles : Automobiles powered by diesel engine. e.g: Trucks, Buses, Tractors.
Gas vehicles : Vehicles that use gas turbine as power source. e.g: Turbine powered cars.
Electric vehicles : Automobiles that use electricity as a power source. e.g: Electric cars, electric buses.
Steam Engine vehicles : Automobiles powered by steam engine. e.g: Steamboat, steam locomotive,
steam wagon.
4. Based on Drive of the vehicles:
Left Hand drive : Steering wheel fitted on left hand side.
Right Hand drive : Steering wheel fitted on right hand side.
Fluid drive : Vehicles employing torque converter, fluid fly wheel or hydramatic transmission.
5. Based on number of wheels and axles:
Two wheeler : motor cycles, scooters
Three wheeler : Tempo, auto-rickshaws
Four wheeler : car, Jeep, Bus, truck Six wheeler : Buses and trucks have six tires out of which four are carried on the rear wheels for additional reaction.
Six axle wheeler : Dodge(10 tire) vehicle
6. Based on type of transmission:
Automatic transmission vehicles: Automobiles that are capable of changing gear ratios automatically as they move. e.g: Automatic Transmission Cars.
Manual transmission vehicles: Automobiles whose gear ratios have to be changed manually. Semi-automatic transmission vehicles: Vehicles that facilitate manual gear changing with clutch
pedal.
7. Based on Suspension system used:
Convectional – Leaf Spring
Independent – Coil spring, Torsion bar,
Pneumatic.

Bernoulli’s Principle and Equation

During 17^th century, Daniel Bernoulli investigated the forces present in a moving fluid, derived an equation and named it as an Bernoulli’s Equation. Below image shows one of many forms of Bernoulli’s equation.
The Bernoulli equation gives an approximate equation that is valid only in inviscid regions of flow where net viscous forces are negligibly small compared to inertial, gravitational or pressure forces. Such regions occur outside of boundary layers and waves

The Bernoulli Equation can be considered to be a statement of the conservation of energy principle appropriate for flowing fluids. The qualitative behavior that is usually labeled with the term "Bernoulli effect" is the lowering of fluid pressure in regions where the flow velocity is increased. This lowering of pressure in a constriction of a flow path may seem counterintuitive, but seems less so when you consider pressure to be energy density. In the high velocity flow through the constriction, kinetic energy must increase at the expense of pressure energy.

Steady-state flow caveat: While the Bernoulli equation is stated in terms of universally valid ideas like conservation of energy and the ideas of pressure, kinetic energy and potential energy, its application in the above form is limited to cases of steady flow. For flow through a tube, such flow can be visualized as laminar flow, which is still an idealization, but if the flow is to a good approximation laminar, then the kinetic energy of flow at any point of the fluid can be modeled and calculated. The kinetic energy per unit volume term in the equation is the one which requires strict constraints for the Bernoulli equation to apply - it basically is the assumption that all the kinetic energy of the fluid is contributing directly to the forward flow process of the fluid. That should make it evident that the existence of turbulence or any chaotic fluid motion would involve some kinetic energy which is not contributing to the advancement of the fluid through the tube.
It should also be said that while conservation of energy always applies, this form of parsing out that energy certainly does not describe how that energy is distributed under transient conditions. A good visualization of the Bernoulli effect is the flow through a constriction, but that neat picture does not describe the fluid when you first turn on the flow.
Another approximation involved in the statement of the Bernoulli equation above is the neglect of losses from fluid friction. Idealized laminar flow through a pipe can be modeled by Poiseuille's law, which does include viscous losses resulting in a lowering of the pressure as you progress along the pipe. The statement of the Bernoulli equation above would lead to the expectation that the pressure would return to the value P₁ past the constriction since the radius returns to its original value. This is not the case because of the loss of some energy from the active flow process by friction into disordered molecular motion (thermal energy). More accurate modeling can be done by combining the Bernoulli equation with Poiseuille's law. A real example which might help visualize the process is the pressure monitoring of the flow through a constricted tube.
   

Despite its simplicity, Bernoulli’s Principle has proven to be a very powerful tool in fluid mechanics.
Care must be taken when applying the Bernoulli equation since it is an approximation that applies only to inviscid regions of flow. In general, frictional effects are always important very close to solid walls and directly downstream of bodies.
The motion of a particle and the path it follows are described by the velocity vector as a function of time and space coordinates and the initial position of the particle. When the flow is steady, all particles that pass through the same point follow the same path and the velocity vectors remain tangent to the path at every point.

 

 

 

 

 

During 17^th century, Daniel Bernoulli investigated the forces present in a moving fluid, derived an equation and named it as an Bernoulli’s Equation. Below image shows one of many forms of Bernoulli’s equation.

 

 

The Bernoulli equation gives an approximate equation that is valid only in inviscid regions of flow where net viscous forces are negligibly small compared to inertial, gravitational or pressure forces. Such regions occur outside of boundary layers and waves - See more at: http://www.me-mechanicalengineering.com/bernoullis-principle-and-equation/#sthash.2lIUkDNX.dpuf

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.

DIFFERENCE BETWEEN AN ENGINEER AND ASCIENTIST FROM JAZIB SAEED KHAN'S BLOG

Engineer vs scientist - Difference between an engineer and a scientist - “I always wanted to be an engineer. And today as I see the magnificent artifacts that have been created by me I feel so lucky that I landed in a profession of my choice”. Well these are the words of a random person who happens to be an engineer by default. And believe  me if he were a scientist, he would have said the same thing. And so the hot point is: we really never know what makes an engineer different from a scientist.
Ironically people differentiate scientists from engineers by the level of personality they own. Engineers are often regarded as cool people with highly paid jobs who have nothing to do in the world but to make all the important decisions. Scientists on the other hand are regarded as the hapless
people who spend most of their lives with lab rats thinking over the issues that have nothing to do with a common man. This is the main reason most students want to take up engineering as the future
profession although they never realize that engineering is a multifaceted endeavor and they will have no exposure towards it until the end of the high school. And this happens to be the most important reason that most people never realize that a scientist and an engineer are indeed very different with different aims and indeed different priorities.
Differentiating engineering from science is a matter of how we look at the two professions in the real
world. An engineer’s priority should be to take up real world challenges and complete them in real time so that people may get the desired results and benefits. So in a way, we can regard that an engineer is closer to the common man than a scientist. It is just an opinion not a well established fact.
A scientist on the other hand should have the insight to perceive the upcoming future. And that is the fun part. A scientist mostly lives in a virtual world full of random and abstract thoughts that combine to form a solution. An engineer on the other hand lives in a real world that we all can see and feel. And that is the main reason that most of the work done by the scientist does not become inevitable at once.
Engineers often argue that their job is more innovative than the job of an average scientist who has to live with a bunch of lab rats all day long doing nothing. Well this perception is absolutely wrong. Inevitably engineering is a very versatile profession but innovation is just a part of it. A scientist on the other hand lives merely on innovation. Working in a virtual world is no easy task which requires loads of innovation in store.
Sometimes it is very difficult to draw a clear boundary between the two professions. Both have contributed immensely towards the development of this world. And it would be true to say that both are the wheels of the same car. Instead of discriminating them, we should try to bridge the two professions so that the world can really see what happens behind the scenes. I hope this article gives
you a good idea about difference between an engineer and a scientist.

Why engineers are not getting job offers?Ever thought why engineers are not getting joboffers?

There are so many reasons behind every rejection. It takes time to learn skills which are required for successful job interviews. Every day I get so many messages from confused fresh graduates and engineers from all over the world who ask me to help then in getting a job. From these messages, it is very clear that they are trying hard to reach out to fellow engineers and they are putting their best efforts in finding a job. But all these efforts are in WRONG direction. Here I would like to share some common reasons of interview rejection and why engineers are not getting job offers.

I have gone through all these phases of life. It hard to understand all these reasons at start of career but over time you start to realize your mistakes. Here i would share my personal experiences. Not preparing for interview I have seen many candidates who do not prepare for interviews. Interview is just like an exam, if you do not prepare, you will fail. Preparation for an interview includes looking for answers to common engineering interview questions, revising basic concepts of mechanical engineering courses, and dressing up properly for interview. General format of CV for all jobs I have seen many candidates who have a general format of CV to apply for all type of jobs. A good engineer will always make changes to his CV according to job description. Applying for too many posts in same organization/ company
Recently we are short listing engineering candidates for job interviews in my company. I have noticed so many candidates who applied for all positions with same CV. Is it logical applying for Manager Operations, Assistant manager operations, Assistant manager admin and Assistant operations at the same time? We rejected many candidates for this reason. Always be crystal clear about job position that you want to apply for.
Standing out too much Only add relevant information to your CVs and portfolio. Adding too much colors, extra information and irrelevant skills will not make any difference.
What is in it for me?
Always ask questions from your interviewer. Try to learn what is in this job for you? What opportunities of learning do you have? Is it suitable for you? This will help you decide whether the company is right for you.
Interview answers
Always prepare for potential common interview questions. Many engineers do not get job offers because they do not give satisfactory answers to some tricky questions. During all interviews, some
questions are of general nature while some questions are of technical nature.
Overconfidence
Overconfidence simply kills.
Lack of job information
Lack of job information and knowledge about possible job description gives a very bad impression about candidate. I once applied for a job position in a company dealing with water treatment plants. Reason for my rejection was that I could not explain how I would become a contributing member to this company because I was unaware of job description.
Non-confidence in employers’ recruitment procedure
Always show confidence in employers’ recruitment procedure. If they have called you for an interview, it means they are trying hard to do it on merit.
Always speak truth
Always speak truth. Those who are interviewing you, are experienced enough to catch false information through discussions.
Be yourself, be original
As simple as that: Be yourself, be original

How to go for internship?

I do not want to spread any kind of negativity, but from my personal experience if your college is not a very reputed and recognized one then it can be almost impossible for you to get a decent paid internship. No matter what you are good in, no matter how hard you try its almost negligible chance for you to land at a nice internship. But still there are some ways which I will edit later OK lets start:

1.) If your college has a mechanism for internships then the companies will come for hiring interns as
they come for hiring employees, chose the company wisely according to you interest and learning opportunity not according to the stipend.
2.) If your college does not have a proper mechanism then you can ask your TPO to give you some contacts of local companies and a recommendation letter from your TPO and department professor would be helpful.
3.) If the above 2 are not applicable then its a long way to go...bear with me:
You need to actively look for internship opportunities on internet(almost 5-6 times in a day) and I would recommend you to start in the month of December.
Some of the websites which you can refer are:
a.) Internship | Summer Training | Paid Internships | Summer Internship 2014 subscribe on internshala and you will get the recent internship directly on your mail id.
b.) Internships and Internship Jobs in India
c.) Look for research internships on the websites of  IITs and IISC, some of the programs are:
SURGE : IIT Kanpur; IITJ-Indian Institute of Technology Jodhpur : UGRI,; IIT Jodhpur and almost every IIT has such program. Moreover if you are interested in research in a particular topic then you may contact the professors from elite institutions directly by going through their profile from the Institute website. But for this you need to make a strong case in front of him backing your interest and eligibility.
Likewise there are many more similar platforms on which you can search for internships.
4.) You may contact your college alumni to seek their help.
5.) Visit the career page of the websites of various companies, many companies directly call for applications or you may contact their HR
6.) Still if you can not land at an awesome internship then you can go for Industrial training but do not waste all of your vacation time unless you are preparing for some competitive exam. Now we come to the application, Cover letter and mail sending:
1.) Now that you have searched an internship and you are going to apply for it, keep these things in
mind:
a.) Your resume highlights the similar work done by you in college for which you are applying
b.) Make a standard resume, you can get help from many references on internet like Resume writing ppt presentation and similar. Also search for resume of IITB students online.
c.) Write a professional mail mentioning your interest and relevancy, avoid including jargon and irrelevant details
d.) Do not follow up too much
e.) It the cover letter is required then seek for help from your seniors on how to write it or look at the
internet
If you are entering your sophomore or pre-final year then it is highly recommended to develop some professional skills that may vary from branch to branch. It will not only help you in getting a decent internship but will help you in job interviews as well.
Stop wasting time and indulge in co-curricular, extra- curricular activities in college or outside the college. Be part of 1 or 2 clubs that interests you, it shows that you have organisational qualities and team spirit. Highlight your work on your resume.

10 Sites That Every Engineer Should Know About

Here's another post inspired by an office discussion. We were discussing our favourite engineering based websites and realised the results would make a great blog post. So after a rummage through our bookmarks and a little further debate we've come up with our top ten sites. We tried to keep the list balanced so you'll find a few resource sites, a little bit of fun and one or two sites that aren't purely engineering sites, but contain valuable knowledge for engineers. Do you have a favourite site that we haven't included? Why not add a comment below and give your favourites a plug.
1. Engineering.com
A wealth of engineering related news, videos, resources and jobs. Visit... Engineering.com
2. Engineering Formulas
A website packed full of formula for Fluid Mechanics, Failure Criteria, Finance and loads of things that don't begin with F too. A great site for lovers of Greek letters and other squiggles. Other parts of the site have information on materials, units, design and maths. Visit... eFunda: Engineering Formulas
3. The Engineering Toolbox
A great site, well structured into various engineering categories that lets you drill down to find the information you need. The flow of the site is a little spoiled by too many Google Ads links, but that is just a minor irritation.
Visit... The Engineering Toolbox
4. LinkedIn
Not strictly an engineering resource, but LinkedIn is a great place to network with fellow engineers (it's a bit like Facebook for grown-ups) and has some really useful special interest groups for sharing
knowledge, meeting like-minded professionals and exchanging job opportunities.
Visit... LinkedIn
5. GlobalSpec
Calling itself "The Engineering Search Engine", GlobalSpec is packed full of engineering products and suppliers. Has some great email newsletters and product alert emails. You can even find Prosig on GlobalSpec .
Visit... GlobalSpec
6. How Stuff Works
Whenever we need bit of extra background information for an office discussion this website is one of our first ports of call. Packed full of straightforward explanations
Visit... How Stuff Works
7. Eng-Tips Forums
A fine collection of discussion forums, blogs, whitepapers and more. Covers a wide range of engineering fields.
Visit... Eng-Tips Forum
8. Wikipedia
Again, not strictly an engineering site, but Wikipedia can't be ignored when seeking information. Much has been made of the possible innaccuracies of Wikipedia's articles, but genarally the scientific and engineering pages are well maintained.
Visit... Wikipedia
9. Discover Engineering
A fantastic site for students or anyone new to engineering. Or just about anyone who enjoys quirky science projects and engineering themed games and activities. We all need a little light relief, right?
Visit... Discover Engineering
10. Fun-Engineering
Another bit of fun to finish with. Fun-Engineering (maintained by Prof. Jim McGovern of the Department of Mechanical Engineering at the Dublin Institute of Technology) is a great little site, full of engineering gems. To my mind it is sites like this that make the WWW what it is.
Visit... Engineering-Fun