[Thermodynamics] Reversible process And Factor causing internal irreversibility

                   Reversible Process And Factors Causing Internal Irreversibility 



A process is said to be reversible when there are no dissipative effects, all the work done by the syste during the performance of a process in one direction can be returned to the system during the reverse process.


A process will be reversible when it is performed in such a way that the system is all time infinitesimally near a state of thermodynamic equilibrium and in the absence of dissipative effect of any form.


the internal irreversibility is caused by the internal dissipative effects like friction, turbulence, electrical resistance, magnetic hyteresis etc within the system.  

[Thermodynamics] Thermodynamic Equilibrium

                                             Thermodynamic Equilibrium


A system which is simultaneously in a state of mechanical equilibrium, thermal equilibrium and chemical equilibrium is said to be in a state of thermodynamic equilibrium.

When there is no unbalanced force with in the system and it's boundaries, then the system is said to be in mechanical equilibrium.

when there is no change in internal structure due to chemical reactions or diffusion then the system is said to be in chemical equilibrium.

when there is uniformity in temperature then there is thermal equilibrium of the system.

[ Fun Facts] Some Interesting Fun Facts

                           SOME OF THE INTERESTING FUN FACTS

1. Banging your head against a wall burns 150 calories an hour.
2. In the UK, it is illegal to eat mince pies on Christmas Day!
3. Pteronophobia is the fear of being tickled by feathers!
4. When hippos are upset, their sweat turns red.
5. A flock of crows is known as a murder.
6. “Facebook Addiction Disorder” is a mental disorder identified by Psychologists.
7. The average woman uses her height in lipstick every 5 years.
8. 29th May is officially "Put a pillow on your fridge day".
9. Cherophobia is the fear of fun.
10. Human saliva has a boiling point three times that of regular water.
11. If you lift a kangaroo's tail off the ground it can’t hop.
12. Hyphephilia are people who get aroused by touching fabrics.
13. Billy goats urinate on their own heads to smell more attractive to females.
14. The person who invented the Frisbee was cremated and made into frisbees after he died!
15. During your lifetime, you will produce enough saliva to fill two swimming pools.
16. An eagle can kill a young deer and fly away with it.
17. Polar bears can eat as many as 86 penguins in a single sitting.
18. King Henry VIII slept with a gigantic axe beside him.
19. Bikinis and tampons invented by men.
20. If Pinokio says “My Noes Will Grow Now”, it would cause a paradox. 
21. Heart attacks are more likely to happen on a Monday.
22. If you consistently fart for 6 years & 9 months, enough gas is produced to create the energy of an atomic bomb!
23. An average person’s yearly fast food intake will contain 12 pubic hairs.
24. The top six foods that make your fart are beans, corn, bell peppers, cauliflower, cabbage and milk!
25. There is a species of spider called the Hobo Spider.
26. ‘Penis Fencing’ is a scientific term for the mating ritual between flatworms. It involves two flatworms attempting to stab the other flatworm with their penis.
27. A toaster uses almost half as much energy as a full-sized oven.
28. A baby spider is called a spiderling.
29. You cannot snore and dream at the same time.
30. The following can be read forward and backwards: Do geese see God?
31. A baby octopus is about the size of a flea when it is born.
32. A sheep, a duck and a rooster were the first passengers in a hot air balloon.
33. In Uganda, 50% of the population is under 15 years of age.
34. Hitler’s mother considered abortion but the doctor persuaded her to keep the baby.
35. Arab women can initiate a divorce if their husbands don’t pour coffee for them.
36. Recycling one glass jar saves enough energy to watch TV for 3 hours.
37. Smearing a small amount of dog feces on an insect bite will relieve the itching and swelling.
38. Catfish are the only animals that naturally have an odd number of whiskers.
39. Facebook, Skype and Twitter are all banned in China.
40. 95% of people text things they could never say in person.
41. The Titanic was the first ship to use the SOS signal.
42. In Poole, ‘Pound World’ went out of business because of a store across the road called ’99p Stores’, which was selling the same products but for just 1 pence cheaper! 
43. About 8,000 Americans are injured by musical instruments each year.
44. The French language has seventeen different words for ‘surrender’.
45. Nearly three percent of the ice in Antarctic glaciers is penguin urine.
46. Bob Dylan’s real name is Robert Zimmerman.
47. A crocodile can’t poke its tongue out :p
48. Sea otters hold hands when they sleep so they don’t drift away from each other.
49. A small child could swim through the veins of a blue whale.
50. Bin Laden’s death was announced on 1st May 2011. Hitler’s death was announced on 1st May 1945.
51. J.K. Rowling chose the unusual name ‘Hermione’ so young girls wouldn’t be teased for being nerdy!
52. Hewlett-Packard’s name was decided in a coin toss.
53. The total number of steps in the Eiffel Tower are 1665.
54. The Pokémon Hitmonlee and Hitmonchan are based off of Bruce Lee and Jackie Chan.
55. The toothpaste ‘Colgate’ in Spanish translates to ‘go hang yourself’. 
56. Pirates wore earrings because they believed it improved their eyesight.
57. Los Angeles’s full name is “El Pueblo de Nuestra Senora la Reina de los Angeles de Porciuncula.”
58. Dr. Kellogg introduced Kellogg Corn Flakes in hopes that it would reduce masturbation.
59. The testicles on an octopus are located in its head!
60. In England, in the 1880’s, “Pants” was considered a dirty word.
61. It snowed in the Sahara desert for 30 minutes on the 18th February 1979.
62. Every human spent about half an hour as a single cell.
63. If you leave everything to the last minute… it will only take a minute.
64. Ithyphallophobia is the fear of erections.
65. The first alarm clock could only ring at 4am.
66. Birds don’t urinate.
67. Dying is illegal in the Houses of Parliaments – This has been voted as the most ridiculous law by the British citizens.
68. The word ‘ejaculation’ comes from the Latin word meaning ‘throwing out’.
69. The 20th of March is known as Snowman Burning Day!
70. Slugs have 4 noses.
71. Panphobia is the fear of everything… which is a pretty unlucky phobia to have.
72. An apple, potato, and onion all taste the same if you eat them with your nose plugged.
73. George Washington grew marijuana in his garden.
74. A company in Taiwan makes dinnerware out of wheat, so you can eat your plate!
75. The average person walks the equivalent of twice around the world in a lifetime.
76. The Bible is the most shoplifted book in the world.
77. Macro Hort has the world record for fitting 264 straws in his mouth at once!
78. Mel Blanc – the voice of Bugs Bunny – was allergic to carrots.
79. California has issued 6 drivers licenses to people named Jesus Christ.
80. According to Genesis 1:20-22 the chicken came before the egg.
81. In the Caribbean there are oysters that can climb trees.
82. Worms eat their own poo.
83. Squirrels forget where they hide about half of their nuts.
84. Over 1000 birds a year die from smashing into windows.
85. The inventor of the Waffle Iron did not like waffles.
86. George W. Bush was once a cheerleader.
87. In Japan, it is completely acceptable to name your child ‘Buttocks’ or ‘Prostitute’.
88. In 1895 Hampshire police handed out the first ever speeding ticket, fining a man for doing 6mph!
89. Each year, there are more than 40,000 toilet related injuries in the United States.
90. A tapir has the largest penis-to-body ratio of any animal.
91. Mewtwo is a clone of the Pokémon Mew, yet it comes before Mew in the Pokédex.
92. Every year more than 2500 left-handed people are killed from using right-handed products.
93. Madonna suffers from garophobia which is the fear of thunder.
94. China has more English speakers than the United States.
95. Samuel L. Jackson requested to have a purple light saber in Star Wars in order for him to accept the part as Mace windu.
96. Paraskavedekatriaphobia is the fear of Friday the 13th!
97. Kleenex tissues were originally used as filters in gas masks.
98. In 1998, Sony accidentally sold 700,000 camcorders that had the technology to see through people’s clothes. These cameras had special lenses that use infrared light, which allowed you to see through some types of clothing.
99. Upon losing battles, apes will tend to masturbate.
100. Ronald McDonald is “Donald McDonald” in Japan because it makes pronunciation easier for the Japanese. In Singapore he’s known as “Uncle McDonald”.

[Thermodynamics] The reason why carnot cycle not practicable for a steam power plant

           WHY CARNOT CYCLE IS NOT PRACTICABLE FOR A STEAM POWER PLANT


Theoretically, a carnot cycle is most efficient, however, the following difficulties are associated with it when steam is the working fluid.

• Steam condensation is not allowed to proceed to completion. The condensation process is controlled one.
• The working fluid after condensation process is both in the liquid and vapour state, and these do not form a homogeneous mixture. It is rather difficult to compress the two phase mixture isentropically. 
• The vapour has a large specific volume and to accomodate greater volumes, the size of the compressor becomes quite big.
• For running a large sized compressor more powder is required and that results in a poor plant efficiency.
• Carnot cycle has high specific steam consumption, large back work ratio and low work ratio.
• The steam at exhaust from the turbine is of low quality i.e., high moisture content. The liquid water droplets cause pitting and hence erosion of the turbine blades.

So, carnot cycle is not suitable for steam power plant.

Just for an idea,
This is how the classical Carnot Heat Engine Looks...

[Database Management System] Super Key, Primary key and Foreign key in Context of relational database model

SUPER KEY

• A set of one or more attribute taken collectively which can identify a record uniquely from a relation.
• Example:  {roll_no} is a super key in student relation.
• Let AK be a set of attributes of a relations R and let t1 and t2 be the two tuples in r of R, then AK will be the super key of relation R if t1{AK} is not equal to t2{AK}
•           A           B           C                                                                                                                                                         a1          b1         c1                                                                                                                                                       a2         b2         c2                                                                                                                                                       a3         b3         c3                                                                                                                                                                                                                                                                                                                                     Here {AB}, {BC}, {AC}, {ABC} are super keys of R.
• The set of all attributes of a relation is a default super key of relation
• The super key contains extraneous attributes

PRIMARY KEY

• It is a specific key which consist of most independent attributes.
• When an attribute is defined to be  a primary key, then every incoming value is tested to be non-null and unique.
• Example:                                                                                                                                                                    Roll_no is primary key to student relation

FOREIGN KEY

• In a relation, the column whose values corresponds to the values of key column in other relation is called Foreign key.
• Example:                                                                                                                                                                                                                                                                                                                                                           Product= Pro_code Name | Supp_code                 (Pro_code ->Product_Code,                                                                                                                               Supp_code -> Supplier_Code,                                                                                                                   So here Pro_code is primary key)

           Supplier=Supp_code | Supp_name                            (Supp_code -> Supplier_Code,                                                                                                                                     Supp_name -> Supplier name,

                                                                                                           So here Supp_code is Foreign Key)

(Note all these definitions or statements were taken from different sources from web ) 

:) 

[E-Commerce] Different Components Of A Business Model

                                  DIFFERENT COMPONENTS OF A BUSINESS MODEL

The Challenges differ from industry to industry, but let's discuss about some seven basic components of business model:

Reaching Customers:
It's a proverb "Built a better mousetrap, and the world will beat a path to your door." The reality is that even if you did, no one would find you. Even when you know who your prospects are, it's usually difficult and costly to reach them. You have to find them via the internet and email or the old fashioned way-through broadcast media,print ads, direct mail, telemarketing or references or by cold-calling. And these potential customers are not likely to be waiting to hear from you and may not respond to you. So be sure you know how you are going to find and reach them.

Differentiating Your Product:
You think you have got the very best solution, but so does the other girl (or guy). There's always competition, whether you realize it or not. Smart marketing executives know how to develop unique product-positioning strategies that highlight a product's true value. You need to thoroughly understand the competition and effectively communicate the unique advantages of your product.

Pricing:
One of the most basic decisions you have to make is how much you're going to change for your product or services. Giving your stuff away is the way to go on the web, but remember that you still need to figure out how you are eventually going to make money-you can't make it up on volume. Start by understanding how much customer's value what they're gaining from you. Then you need to estimate your total costs, analyze the competitive landscape, and map out your long-term strategy. For your company to survive, your product's price must be greater that its overall cost.

Selling:
Persuading customers to buy a product that they need is one of the most important skill an entrepreneur must learn. You're going to be selling at every juncture. So you have to understand what it takes to close a deal and put together the necessary sales process. And this process has to be perfectly conceived. Be sure you test your selling strategy.

Delivery/Distribution:
This is easy on the Internet. But for big-ticket items, you usually require a direct sales force, for mid-range products, distributors or value-added resellers and for low-priced items, retail outlets or the internet. It's different in every industry and for every type of product, but you have to get this right. Your products needs to be designed and packaged for the channel through which they will be distributed to customers.

Supporting Customers:
In addition to teaching customers how to use your product, you need to ensure that you can deal with defects and returns, answer product questions and listen to and incorporate valuable suggestions for improvement. You may need to provide consulting services to help customers integrate and implement your products. If your product is critical component of a business, you may also need to provide 24/7 onsite or web support.

Achieving Customer Satisfaction
The Ultimate success or failure of a business depends on how much it helps customers achieve their objectives. happy customers will become your best sales people and buy more from you. unhappy customers will become your biggest liability.



In Case if you don't know:

Function of a Business Model:-
1. To articulate the value proposition
2.To identify a market segment
3.To define the structure of the firm's value chain
4.To specify the revenue generation mechanism
5.To describe the position of the firm within the value network
6.To formulate the competitive Strategy



(Note: This definitions and statements were taken from different sources on web, they are of their respective owners) :)