Wednesday, 26 May 2021

MAHARASTRA POLYTECNIC 4th SEM ENVIRONMENTAL STUDIED MICROPROJECT

 MICRO PROJECT OF ENVIRONMENTAL STUDIED 22447

OZONE LAYER DEPLETION 

BASED ON MSBTE 

THAT MICRO PROJECT APROVED BY MSBTE AND POLYTECNIC ALSO

 SO U CAN USE THAT TO COMPLETE  YOUR PROJECT WITH 5+  GRADE 

THAT MICRO PROJECT USE ALL OVER INDIA POLYTECNICS THAT WAS USE SIMPLE  METHOD TO COMPLETE THAT PROJECT

 PDF FILE OF PROJECT:- 

 https://drive.google.com/file/d/1VO1HmVGJkqCQGbUa-kOvoeFXZ8P5cp-D/view?usp=sharing


 

Aim of micro project: 

      1)   To study of OZONE LAYER DEPLETION.

  2) To impact basic knowledge about OZONE LAYER DEPLETION.

   3) Gain knowledge about OZONE LAYER AND OZONE LAYER DEPLETION

Proposal Methodolog

     1)  We started to make micro project on Ozone layer Depletion . after when this topic give to us by teacher.

  2) We had made ppt on Ozone layer Depletion

 3)After that we started to make it  with the help of our team members and under the guidance of our teacher.

4) We made our ppt on word app and from which it becomes easy to make it.

5) We distributed and made it with unity.

6)It takes near about fewdays to complete  our microproject when we started to make it in team.

7)We discussed with each other and performed the microproject.

8. Discussion is one of the most important part of making the microproject in group.

9)So, we completed this task very  easily.


INTRODUCTION

          The ozone layer is found in the lower portion of the earth’s atmosphere. It has the potential to absorb around 97-99% of the harmful ultraviolet radiations coming from the sun that can damage life on earth. If the ozone layer was absent, millions of people would develop skin diseases and may have weakened immune systems.

        However, scientists have discovered a hole in the ozone layer over the Antarctic. This has focussed their concern on various environmental issues and steps to control them. The main reasons for the ozone hole are chlorofluorocarbons, carbon tetrachloride, methyl bromide and hydrochlorofluorocarbons.

 

Ozone Layer Depletion

 

 

“Ozone layer depletion is the gradual thinning of the earth’s ozone layer in the upper atmosphere caused due to the release of  chemical compounds containing gaseous bromine or chlorine from industries or other human activities.” One chlorine can destroy 100,000 molecules of ozone. It is destroyed more quickly than it is created.

Some compounds release chlorine and bromine on exposure to high ultraviolet light, which then contributes to the ozone layer depletion. Such compounds are known as Ozone Depleting Substances (ODS).

          The ozone-depleting substances that contain chlorine include chlorofluorocarbon, carbon tetrachloride, hydrochlorofluorocarbons, and methyl chloroform. Whereas, the ozone-depleting substances that contain bromine are halons, methyl bromide, and hydro bromofluorocarbons. Chlorofluorocarbons are the most abundant ozone-depleting substance. It is only when the chlorine atom reacts with some other molecule, it does not react with ozone. Montreal Protocol was proposed in 1987 to stop the use, production and import of ozone-depleting substances and minimize their concentration in the atmosphere to protect the ozone layer of the earth.

 


 

Causes of Ozone Layer Depletion

  

 Depletion The ozone layer is a major concern and is associated with a number of factors. The main causes responsible for the depletion of the ozone layer are listed below:

 

 

 

 

 

 

1)    Chlorofluorocarbons

Chlorofluorocarbons or CFCs are the main cause of ozone layer depletion. These are released by solvents, spray aerosols, refrigerators, air-conditioners, etc.

The molecules of chlorofluorocarbons in the stratosphere are broken down by the ultraviolet radiations and release chlorine atoms. These atoms react with ozone and destroy it.

 

2)    Unregulated Rocket Launches

       Researches say that the unregulated launching of rockets result in much more depletion of ozone layer than the CFCs do. If not controlled, this might result in a huge loss of the ozone layer by the year 2050.

 

3)    Nitrogenous Compounds

     The nitrogenous compounds such as NO2, NO, N2O are highly responsible for the depletion of the ozone layer.

 

4)    Natural Causes

       The ozone layer has been found to be depleted by certain natural processes such as Sun-spots and stratospheric winds. But it does not cause more than 1-2% of the ozone layer depletion.

The volcanic eruptions are also responsible for the depletion of the ozone layer.

5)    Ozone Depleting Substances (ODS)

“Ozone depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. that are responsible for the depletion of ozone layer.”

 


 

Effects Of Ozone Layer Depletion

  

   The depletion of the ozone layer has harmful effects on the environment. Let us see the major effects of ozone layer depletion on man and environment.

 

01 :- Effects on Human Health

The humans will be directly exposed to the harmful ultraviolet radiations of the sun due to the depletion of the ozone layer. This might result in serious health issues among humans, such as skin diseases, cancer, sunburns, cataract, quick ageing and an weakend immune system.

 

02:-  Effects on Animals

Direct exposure to ultraviolet radiations leads to skin and eye cancer in animals.

 

03:- Effects on the Environment

Strong ultraviolet rays may lead to minimal growth, flowering and photosynthesis in plants. The forests also have to bear the harmful effects of the ultraviolet rays.

 

04:- Effects on Marine Life

Planktons are greatly affected by the exposure to harmful ultraviolet rays. These are higher in the aquatic food chain. If the planktons are destroyed, the organisms present in the lower food chain are also affected.

 

 


 

Solutions OF Ozone Layer Depletion

    

      The depletion of the ozone layer is a serious issue and various programmes have been launched by the government of various countries to prevent it. However, steps should be taken at the individual level as well to prevent the depletion of the ozone layer.

Following are some points that would help in preventing this problem at a global level:

 

1)   Avoid Using Pesticides

Natural methods should be implemented to get rid of pests and weeds instead of using chemicals. One can use eco-friendly chemicals to remove the pests or remove the weeds manually.

2)   Minimize the Use of Vehicles

The vehicles emit a large amount of greenhouse gases that lead to global warming as well as ozone depletion. Therefore, the use of vehicles should be minimized as much as possible.

 

3)   Use Eco-friendly Cleaning Products

Most of the cleaning products have chlorine and bromine releasing chemicals that find a way into the atmosphere and affect the ozone layer. These should be substituted with natural products to protect the environment.

 

4)    Use of Nitrous Oxide should be Prohibited

The government should take actions and prohibit the use of harmful nitrous oxide that is adversely affecting the ozone layer. People should be made aware of the harmful effects of nitrous oxide and the products emitting the gas so that its use is minimized at the individual level as well.

 

 


 

Ozone depletion over India

 

         With so much worry about the rapid ozone depletion taking place in various parts of the earth, Indian scientists are closely monitoring the ozone layer over India for possible depletiontrends. Opinions are many and varied. According to S K Srivastava, head of the National Ozone Centre in New Delhi,there is no trend to show total ozone depletion over India.V.Thaphyal and S M Kulshresta of the Indian Meteorological Department also point out that for the period 1956 to 1986 "ozone measurements exhibit year to year variability, but do not show any increasing or decreasing trend over India." However, former director of the National Ozone Centre, K Chatterji, now with Development Alternatives, warns that there is no case for complacency. He asserts that his calculations exhibit an ozone depletion trend in the upper, layers of the stratosphere over New Delhi and Pune from 1980 to 1983 in the month of October when the Antarctic ozone hole is at its maximum. Since India already receives high doses of ultraviolet (UV-B) radiation, and is at the threshold go to speak, effects of ozone layer depletion could he far more disastrous in India. A P Mitra, former director general of the Council of Scientific and Industrial Research, clarifies that while there is no trend in the total ozone value, there is some evidence of ozone depletion at higher altitudes - at about 30 to 40 km - even over the tropics. He argues, however, that there is insufficient data and that the depletion may be due to solar cycles and other natural phenomena.

      

           However, the effects of CFCs and belong cannot be ruled out.Total column ozone data has been recorded over India for a long time. A network of stations using Dobson spectrophotometers to mea- sure total ozone, some six times a day, covers Srinagar, New Delhi, Varanasi, Ahmedabad, Pone and Kodaikanal. Ozone profiles are also regularly recorded using balloons. Ozone levels are the lowest during November and December and the highest in summer. Across the country, variations do exist. In Kodaikanal, the total ozone is 240 to 280 Dobson units (DU), in New Delhi 270 to 320 DU and in Srinagar 290 to 360 DU. One Dobson unit is the equivalent of 0.01 mm of compressed gas at a pressure of 760 rare mercury and 0°C.B N Srivastava of the National Physical Laboratory, who been working on incident UV- radiation levels, says that during summer, at noon, the UV-B  radiation with a wavelength of 290 nanometer (nm) is equivalent to levels attained in the Antarctica during the ozone hole period. He warns that even a slight depletion of the ozone layer over India may lead to large percentage changes in UV-B radiation over the country. According to eminent skin specialists in New Delhi, the incidence of skin cancer in India is low, but they admit that the surveys conducted to identify any trends are inadequate. Controlled studies to observe the effects of changing UV- B radiation concentrations on crops are on, they said. However no field surveys have been done in the country as yet.     


 

 

REFERRENCES

01)        BY USING THE GOOGLE MEDIA

02)       HAND BOOK OF ENVIMENTAL STUDIED

03)       BOOK OF ENVIRONMENTAL SCIENCE

04)        AND OTHER ENVIRONMENTAL BOOKS   

                  

Friday, 21 May 2021

MICROPROJECT OF THERMAL ENGINEERING- charts on fundamental concepts of THERMODYNAMICS

 

A

PROJECT REPORT

To

PREPARE CHARTS ON

FUNDAMENTAL CONCEPTS OF

THERMODYNAMICS – SECOND LAW OF THERMODYNAMICS


          LINK OFF PDF OF MICRO PROJECT :-

    https://drive.google.com/file/d/1mCu9wa631e1L6xDsyvxewUfDAt-b0EDk/view?usp=sharing




         THAT PDF IS SUBMITTED BY ME AND MY FRIENDS SO YHAT WAS 4 STAR PROJECT AND THAT APPROVED BY MSBTE.

  Basic Concepts of Thermodynamics Every science has its own unique vocabulary associated with it. Precise definition of basic concepts forms a sound foundation for development of a science and prevents possible misunderstandings. Careful study of these concepts is essential for a good understanding of topics in thermodynamics. Thermodynamics and Energy Thermodynamics can be defined as the study of energy, energy transformations and its relation to matter. The analysis of thermal systems is achieved through the application of the governing conservation equations, namely Conservation of Mass, Conservation of Energy (1st law of thermodynamics), the 2nd law of thermodynamics and the property relations. Energy can be viewed as the ability to cause changes.   First law of thermodynamics: one of the most fundamental laws of nature is the conservation of energy principle. It simply states that during an interaction, energy can change from one form to another but the total amount of energy remains constant. Second law of thermodynamics: energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy. Whenever there is an interaction between energy and matter, thermodynamics is involved. Some examples include heating and air‐conditioning systems, refrigerators, water heaters, etc.

Energy In thermodynamics, we deal with change of the total energy only. Thus, the total energy of a system can be assigned a value of zero at some reference point.  Total energy of a system has two groups: macroscopic and microscopic. Macroscopic forms of energy: forms of energy that a system posses as a whole with respect to some outside reference frame, such as kinetic and potential energy. The macroscopic energy of a system is related to motion and the influence of some external effects such as gravity, magnetism, electricity, and surface tension.

Irreversibility

The second law of thermodynamics deals with the direction taken by spontaneous processes. Many processes occur spontaneously in one direction only—that is, they areirreversible, under a given set of conditions. Although irreversibility is seen in day-to-day life—a broken glass does not resume its original state, for instance—complete irreversibility is a statistical statement that cannot be seen during the lifetime of the universe. More precisely, an irreversible process is one that depends on path. If the process can go in only one direction, then the reverse path differs fundamentally and the process cannot be reversible.

For example, heat involves the transfer of energy from higher to lower temperature. A cold object in contact with a hot one never gets colder, transferring heat to the hot object and making it hotter. Furthermore, mechanical energy, such as kinetic energy, can be completely converted to thermal energy by friction, but the reverse is impossible. A hot stationary object never spontaneously cools off and starts moving. Yet another example is the expansion of a puff of gas introduced into one corner of a vacuum chamber. The gas expands to fill the chamber, but it never regroups in the corner. The random motion of the gas molecules could take them all back to the corner, but this is never observed to happed 

Second Law of Thermodynamics

The fact that certain processes never occur suggests that there is a law forbidding them to occur. The first law of thermodynamics would allow them to occur—none of those processes violate conservation of energy. The law that forbids these processes is called the second law of thermodynamics. We shall see that the second law can be stated in many ways that may seem different, but these many ways are, in fact, equivalent. Like all natural laws, the second law of thermodynamics gives insights into nature, and its several statements imply that it is broadly applicable, fundamentally affecting many apparently disparate processes. The already familiar direction of heat transfer from hot to cold is the basis of our first version of the second law of thermodynamics.




Wednesday, 19 May 2021

MECHANICAL ENGINEERING, THEORY OF MACHINE standard MCQ Quetions and Answers.

THEORY OF MACHINE STANDARD

 MCQ ANSWERS AN QUATIONS
 BASED ON MECHANICAL ENGINEERING

1. The type of pair formed by two elements which are so connected that one is constrained to turn or revolve about a fixed axis of another element is known as
A.Turning pair
B.Rolling pair
C.Sliding pair
D.Spherical pair

ANS :-  A. TURNING PAIR

2. Which of the following is a lower pair
A.Ball and socket
B.Piston and cylinder
C.Cam and follower (a) and (b) above
D.Belt drive.

ANS:- D. BELT DRIVE

3. If two moving elements have surface contact in motion, such pair is known asi
A.Sliding pair
B.Higher pair.
C.Surface pair
D.Lower pair

ANS;- B. HIGHER PAIR

4. The example of lower pair is
A.Shaft revolving in a bearing
B.Straight line motion mechanisms
C.Automobile steering gear
D.All of the above

ANS;- D. ALL THE ABOVE

5. Pulley in a belt drive acts as
A.Cylindrical pair
B.Turning pair
C.Rolling pair
D.Sliding pair

ANS ;-C.  ROLLING PAIR

 6. The example of rolling pair is
A.Bolt and nut
B.Lead screw of a lathe
C.Ball and socket joint
D.Ball bearing and roller bearing

ANS:- D. BALL BEARING AND ROLLER BEARING

7. Any point on a link connecting double slider crank chain will trace a
A.Straight line
B.Circle
C.Ellipse
D.Parabola

ANS:- C. ELLIPSE

8. Kinematic pairs are those which have two elements that
A.Have line contact
B.Have surface contact
C.Permit relative motion
D.Are held together

ANS :- C. PERMIT RELATIVE MOTION

9. A simple mechanism has
A.1 link
B.2 links
C.3 links
D.4 links

ANS:- D. 4LINKS
10. The lower pair is a
A.Open pair
B.Does not exist.
C.Sliding pair
D.Point contact pair

ANS :- B. DOES NOT EXIST

11. Automobile steering gear is an exrimple of
A.Higher pair
B.Lower pair.
C.Turning pair
D.Rotary pair

ANS ;- B. LOWER PAIR

12. In higher pair, the relative motion is
A.Purely turning
B.Combination of sliding and turning.
C.Purely rotary
D.Purely surface contact

ANS :-B. COMBINATION OF SLIDING AND TURNING

13. Which of the following has sliding motion
A.Crank
B.Connecting rod
C.Crank pin
D.Crosshead

ANS ;-D. CROSSHEAD

14. The;,example of higher pair is
A.Belt, rope and chain drives
B.Gears, cams
C.Ball and roller bearings
D.All of the above

ANS ;- D. ALL OF THE ABOVE

15. Thepurpose of a link is to
A.Transmit motion
B.Guide other links
C.Act as a support
D.All of the above

ANS :- D. ALL OF THE ABOVE

16.. A universal joint is an example of
A.Higher pair
B.Lower pair
C.Rolling pair
D.Sliding pair

ANS :- B. LOWER PAIR
17. Rectilinear motion of piston is converted into rotary by
A.Cross head
B.Slider crank
C.Connecting rod
D.Gudgeon pin

ANS ;- B. SLIDER CRANK

18. The example of spherical pair is
A.Bolt and nut
B.Lead screw of a lathe
C.Ball and socket joint
D.Ball bearing and roller bearing

ANS ;- C. BALL AND SOCKET JOINT

19. Cross head and guides form a
A.Lower pair
B.Sliding pair.
C.Turning pair
D.Rolling pair
ANS;- B. LOWER PAIR

20. A circular bar moving in a round hole is an example of
A.Incompletely constrained motion
B.Partially constrained motion
C.Completely constrained motion
D.Successfully constrained motion

ANS:- A. INCOMPLETELY CONSTRAINED MOTION

21. If some links are connected such that motion between them can take place in more than one direction, it is called
A.Incompletely constrained motion
B.Partially constrained motion
C.Completely constrained motion
D.Successfully constrained motion

ANS:- A. INCOMPLETELY CONSTRANED MOTION

22. Which of the following mechanism is obtained from lower pair
A.Gyroscope
B.All of the above.
C.Valve and valve gears
D.Generated straight line motions

ANS:- B. ALL OF THE ABOVE

23. Which of the following would constitute a link
A.Piston, piston rings and gudgeon pin
B.Piston, piston-rod and cross head.
C.Piston rod and cross head
D.Piston, crank pin and crank shaft

ANS:- B. PISTON, PISTON ROD AND CROSS HEAD

24. The Scott-Russell mechanism consists of
A.Sliding and turning pairs
B.Sliding and rotary pairs
C.Turning and rotary pairs
D.Sliding pairs only

ANS;- A.SLIDING AND TURNING PAIRS

25. Davis steering gear consists of
A.Sliding pairs
B.Turning pairs
C.Rolling pairs
D.Higher pairs

ANS:-A. SLIDING PAIRS

26. Ackermann steering gear consists of
A.Sliding pairs
B.Turning pairs
C.Rolling pairs
D.Higher pairs

ANS:- B. TURNING PAIRS

27. A completely constrained motion can be transmitted with
A.1 link with pin joints
B.2 links with pin joints
C.3 links with pin joints
D.4 links with pin joints

ANS:- D. 4LINGS WITH PIN JOINTS

28. Oldham's coupling is the
A.Second inversion of double slider crank chain
B.Third inversion of double slider crank chain
C.Second inversion of single slider crank chain
D.Third inversion of slider crank chain

ANS:- B. THIRD ENVENTION OF DOUBLE SLIDER CRANK CHAIN

29. A slider crank chain consists of following numbers of turning and sliding pairs
A.1,3
B.2,2
C.3,1
D.4,0

ANS:- C.3,1
 
30. The type of coupling used to join two shafts whose axes are neither in same straight line nor parallel, but intersect is
A.Flexible coupling
B.Universal coupling
C.Chain coupling
D.Oldham's coupling

ANS:- B. UNIVERSAL COUOLING

31. The advantage of the piston valve over D-slide valve is that in the former case
A.Wear is less
B.Power absorbed is less
C.Both wear and power absorbed are low
D.The pressure developed being high provides tight sealing

ANS;- C. BOTH WEAR AND POWER ABSORBED ARE LOW

32. Flexible coupling is used becAuse
A.It is easy to disassemble
B.It is easy to engage and disengage
C.It transmits shocks gradually
D.It prevents shock transmission and eliminates stress reversals

ANS;- D. IT PREVENTS SHOCK TRANSMISSION AND ELILINATES STRESS REVERSALS

33. The Ackermann steering mechanism is preferred to the Davis type in automobiles because
A.The former is mathematically accurate
B.The former is having turning pair
C.The former is most economical
D.The former is most rigid

ANS:- THE FORMER IS HAVING TURNING PAIR

34. Transmission of Pow4r from the engine to the rear axle of an automobile is by means of
A.Compound gears
B.Worm and wheel method
C.Hooke's joint
D.Crown gear

ANS:- C. HOOKES JOINT

if you want to more mcq's plzz comeent's

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