Ductile vs Brittle material...

 Welcome today's blog.....

Lets us discuss what are the major differences between the Ductile and Brittle Materials...

Most of the materials can undergo significant plastic deformation under tensile stress before the fracture is called as ductile materials. Whereas, the materials which break without significant plastic deformation under tensile stress are called as brittle materials. Ductile materials are steel, copper and glass, concrete is brittle materials. 

In the figure below, the stress-strain diagram is depicted which explains the brittle materials fractures before the plastic deformation under tensile test. Explicitly, sudden fracture takes place however the material absorbs a certain amount of energy before the rapture.

Major differences are;

1. Pre-elongation length of the brittle materials is less than compared to the ductile materials.

2. Ductile materials have more life when subjected to fatigue loading.

3. Ductile materials fail gradually by neck formation under tensile load whereas, the brittle material suddenly breaks.

4. Brittle materials are not used for forming operations such as rolling, forging. 

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What is Brain Drain?

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Let us discuss what is brain drain?

Brain drain is a term that signifies the immigration of talented and educated people leaves the country for better living standards, good exposure, higher education, advanced technological updates and professional opportunities. This happens more in between the developing to developed countries to receive a better state of living with higher salaries. This also led to the use of the resources within the other country which is kind of a key issue for the developing countries. Because the state of immigration depends on the individual country change. 

As per the report, in 2000 almost 180 million people were living outside their home country. Most of them are on a work basis rather than being a student. Still, young people are ready to relocate to earn better and improve their chances to get a good/high paid job. In other words, the country has a shortage of skilled people in specific fields that drain a developing country by providing them work. This is a never-ending process because the person who has the courage and willingness to accept challenges always wants to go out of its comfort zone. This exemplifies the person is ready to work, apply his knowledge in order to leverage the company value. 

Most of us think if we go out of our countries we will see the wonder on earth. This is a myth everything is the same but in different ways. It should be always you accept the opportunities you get in your way but never expect anything out of it. Because this led us to depression as well if we see it couldn't meet what we thought of.

Hope the information provided was helpful. Thanks for reading it.....

Happy Engineers Day...................

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I am back with some interesting content... Today is National Engineers Day, so let us discuss some things about an Engineer. Before we start, we should be grateful to each and everyone for dedicating their lives for technology. The day is celebrated to appreciate and give honour to Mokshagundam Visvesvaraya the Bharat Ratna Awardee.

 

This blog is dedicated to my friends and everyone who is an Engineer. An Engineer is a complete person with unique technological skills. They are the ones who like to solve the real-time problems within their surroundings. To be an Engineer you have to go through an enormous amount of assignments, projects, real-time experiments which makes a person open to solve the existing problems. Engineering is all about the application of science in different aspects of the domain such as Electronics, Computers, Mechanical, etc. Overall, it requires strong requisite in Physics, Mathematics and other basic Engineering applications. 

Based on my experience and the facts; Engineers are in every part of the world and also like to work for other professional destination rather than Engineering, such as Tech Heads, Managerial fields, leading companies, etc. This exemplifies Engineers are capable of doing whatever they want, however, I would say its not about Engineers but everyone can do it. Just need perseverance and hard work to achieve the goal. 

One thing I hate about the Engineers they are immensely arrogant I don't know why, but for me, it's not acceptable. I completely understand you are an Engineer, this world has many other people in way better position than yours, so based on the same legacy they should also be arrogant? 

Life is too short my advice will always help others, share knowledge with others and be a good human. Kindly, respect each and everyone's work it does not matter what they do even if they are working under you. At the end of the day, what you will earn is respect into someone's eyes, not money. I always see people running for money rather than the satisfaction in their life which I understand is an important part of life, but don't be blind. 

I want to end this blog with a quote "You are the ones who make the lives simpler and worth living. Because of you, we are heading towards great success in the technology."

An Engineer is a person who is good with figures/graphs, but who is not an accountant. 

On my behalf, I want to wish each and everyone a HAPPY ENGINEERS DAY......

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Powerback or Pushback for an aircraft?

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Let us discuss what is a power back and pushback method? To move the aircraft from the apron (parked position) to the take-off position, two methods can be used as shown in the figure below. Pushback method uses industrial tractor and/or tugs, whereas the powerback method uses reverse thrust by engine's to push the aircraft away from an airport apron meantime the pilot can start the engines to move forward to the runway. Mostly, the pushback method is used in airports to move the aircraft from the taxi position. Because the powerback is not safe for the aircraft those who have lower mounted engine's as shown in the figure. As per the Aviation rules, there are various risks accounted in the powerback method such as aircraft collision with the surroundings, damaging the engine, a risk to ground staff and the pilot cannot see the tail of an aircraft. Foreign Object Debris provided this due to which this method is not used in common. In addition, the air sucked (vortex of air) by the engines might intake the gravels, metal pieces or any hard object which might damage the engines. Powerback method is used for Boeing Globemaster, Jet MD80, DC9 and Turboprop aircraft's because they have high mounted engines and requires a ground staff to give the directions; however, it is a faster process. Also, it reduces the ground equipment in the airport which are present on the working floor. It is recommended that while performing the powerback method shutdown the airconditioning system because the air sucked by the engines can go into the passenger cabins.

In conclusion, the pushback method saves fuel and is safe.

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Role of a Mechanical Engineer in the New Era...

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Let us discuss what are the roles of a Mechanical Engineer in the current period. Nowadays, the industries are shifting towards automation, leading to optimizing machining time, reduction in human error and higher efficiency. Due to the current trends, most of the leading job opportunities in the industries are also changing their trend to meet the present scenario. Currently, automation is a critical/key topic in every industry as much of the research for the same topics is ongoing. Therefore, considering these factors in this era, current jobs in the industry are:   

1. Instrumentation Engineer

2. Powertrain Engineer 

3. Design Engineer

4. R&D Engineer

All of these are the current jobs opportunities in the industries as every industry is looking for a candidate who is aware of the current technological updates. These jobs are highly skilful which needs an adequate technical background. Transformation of industries leads to new roles in the world.

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Analysis of the Air India Express IX-1344 Dubai to Kerala Crash.

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"Because of this incident didn't publish the regular blog."

I am immensely saddened to hear this unfortunate crash of the "Vande Bharat Mission Flight from Dubai to Kerala". My heartfelt condolences to the family's those who lost their loved one's #RIP. Vande Bharat Mission intends to evacuate the Indians who had been stranded aboard due to COVID-19.  

Let us discuss what could have been a reason behind the crash? The analysis provided here was made according to the available information on the internet and other resources. This will be my opinion based on the information and data don't quote.

"No one can explain the actual reason, the Pilot and Co-Pilot were the one from whom we could. Unfortunately, they are no more with us."

Begining this blog with who commanded the Air India Express Flight from Dubai to Kerala were Pilot Ex-Wing Commander Deepak Vasant Sathe (Captain) and Co-Pilot Akhilesh Kumar.  

Captain Deepak Vasant Sathe was from 58th course of the National Defence Academy, Pune. He was from "Juliet Squadron" and had been awarded the 58 NDA, President Gold Medal. Also won the Sword of Honour at the Air Force Academy in Hyderabad. He worked as a test pilot for the Air force and was accomplished fighter pilot. A test pilot is the one who evaluates the aircraft performance, conducts various tests, performs experiments on the aircraft, solve the related problems, research on aircraft and possess excellent knowledge on it. From this, one can definitely say that the cockpit was under the supervision of a great pilot with his co-pilot. The Pilot was exceptionally well qualified, so deciding to land was not inappropriate; thus, it is out of the question.

 

Although I saw in media and social networks, people are criticising the Pilot and co-pilot about there decision of landing. First of all, the person who is saying in this matter should be ashamed of what they are trending/speaking. How can you question such an experienced pilot work" We should be grateful for what they are/were doing during this Pandemic COVID-9 helping people to come back to there own country by risking their own life. Therefore, don't speak without knowing anything they would not have done it intentionally. 

"It was a black day."

  

Don't talk rubbish and then spread it. I got extremely disturbed/saddened by seeing all this in the news and other media. "Be human think before you talk don't talk nonsense." We should salute their sacrifice in this current situation while saving passengers on board. It could have been more worst than this might have caught fire or crashed. How can we even think about questioning their profession?  

In 2010, a flight from Dubai to Mangaluru Airport went off the runway and fell into a valley 100 meters resulting in the death of 158 people. Because the airport has tabletop runway means the runway is on the hill or the end of the runway is unbounded (i.e., it is next to the gorge, valley, cliff). Today's incident also resembles this case happened in 2010; however, the reason is still uncertain. 

The flight Boeing 737-8HG Registration No. VT-AXH which was an evacuation flight on the Vande Bharat Mission from Dubai to Kerala. The actual landing time (local) was around 7:30 pm at Kozhikode airport. The flight was carrying 191 passengers, excluding the crew members. As per the reports, the weather condition was not good and there was a thunderstorm with heavy rain. According to ATC (Air traffic controller), the visibility was 2000 meter which is sufficient visibility range for a pilot to land safely. In figure 1, the red enclosed circle demonstrates there was high tailwind around 12 knots which is exceptionally high. The airport runway length is 9383 feet which is the optimum length as per DGCA; however, a runway length of around 7000 feet is a short runway. Therefore, the runway length was not a problem behind it; however, the airport has a tabletop runway. Landing in these extreme weather condition with a tabletop runway would have been a challenge for the captain. Due to the excursion of the runway, the aircraft fells into the ditch of 30-35 feet due to which the breakdown of the fuselage occurs and the cockpit directly hits on the ground and pilots died. Since it was raining the runway was wet and the braking action weakens because of low friction leading to Aquaplaning.

Aquaplaning is a phenomenon when the tires come in contact with water surface and losses the grip over the contact surface due to low friction and the tire skids as wheels are locked due to the applied brake pressure. 

Figure 2, depicts the approach path of landing, firstly, the ATC gave clearance to the captain to land on "Runway 28" and the captain says Roger and approaches to land. In figure 2, the "overhead" is the point when the captain approach to landing that is the point after the aircraft starts to descend. As per regulations of the specific runway, the captain should maintain an altitude of 3100 feet and speed 140 knots; however, their approach was stable and was at 166 knots at 3275 altitude which is acceptable and normal landing can be performed, but the captain saw due to the high wind, turbulence and thunderstorms (cloudly weather) they cannot land on the specific runway. Hence, they go around by turning left (after the overhead point) and again try to land on the other "Runway 10". During the second approach, there was a tailwind which means there is a wind in the same direction of landing (wind is flowing from tail to nose) the condition was dangerous. The captain approached to land on "Runway 10" regulations says to maintain 140 knots at 2200 altitude for the specific runway; however, they were at 179 knots at 2250 feet (not a stable approach) + the tailwind + wet runway (Aquaplaning) + not 100% braking pressure. Due to all of these factors, the aircraft crossed the runway and fell into the ditch of around 30-35 feet by crossing the boundaries. As the aircraft proceeded to the ditch, it split into two pieces due to the impact on the aircraft. 

Figure 3, illustrates the altitude and speed of an aircraft on the whole trip and it can be observed that the speed in the second approach was higher than the first approach. As stated above, the speed was higher than recommended this could be one of the reasons due to failure. Now the question arises why did the captain decide to land on "Runway 10" when there was a tailwind because there were turbulence and thunderstorms on the other runway with much turbulence. 

Figure 4 shows the endpoint of "Runway 10" at Kozhikode airport. 

Figure 1: Aviation Meter Radar

     

Figure 2: Landing Scenario

Figure 3: Speed vs Altitude.

Figure 4: Landing Runway 10

This was my analysis based on the information and data I read. The investigation team can only give a clear picture of the crash.     

Miserable crash I hope the families get enough strength towards the loss of their loved ones. #RIP Somber moment. 

For more information, stay in touch with the website mentioned and/or authentic media reports.

1. https://en.wikipedia.org/wiki/Air_India_Express_Flight_1344

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6 Month Strategy for GATE 2021?

Welcome to today's blog...

Let us discuss how to prepare for GATE in a short period of time starting from August-January. In some previous blogs, we have discussed how to approach GATE preparation, how to revise effectively and other related details. 

This blog would be more focused on the six-month strategy towards the preparation of the exam. In the following steps, have mentioned some milestones towards the GATE:

1. Make a mind map for the preparation this account subject-wise preparation schedule. The mind map is a long term goal and will direct you to lead/follow the goal. This step can also be used as a motivation and dedication to the exam.

2. Preparation to be followed in this step:

a. Syllabus preparation.

b. Revision.

c. Old GATE papers.

d. Test series

Subject wise preparation should be done based on the above steps because it will help you to boost your confidence step by step. After you are done with one subject or more, do parallel revision which means you are still in touch with the concepts. Revision should always be done in continuation the gap in revision will lead to failing the concepts.

3. Start the preparation with Major subjects such as TOM, SOM, Fluid Dynamics, Thermodynamics, HMT, Maths. Because these subjects have more weightage in the exam, other subjects can be done after these. 

4. After the above-mentioned subjects are done, start with the revision along with new subjects. Suppose you finish most of the subjects, including major subjects at the end of November, start with mock test and GATE papers subject wise. 

5. In January do the full mock test this will help you to accustom with the paper and the virtual calculator. If you attempt 4-5 full test series, this will undoubtedly help you in the main exam.

6. After mock tests, you might find the performance was not excellent do not worry just starting with revision and recap all the content so that you will be in touch with the syllabus. 

These steps will help you to adapt to the environment of the exam, boost your confidence, how to attempt question within the stipulated time and improve the accuracy. Hope you will find it helpful. 

Thanks for reading it...

  

Why MBA after B.Tech?

Welcome to today's blog...

Let us discuss why people want to do MBA after B.Tech? 

MBA (Masters in Business Administration) 

First of all, an engineer is a total asset of knowledge in the field of engineering and related fields. After engineering, there are many different ways to approach your career, such as Research, Master's, MBA, Associate professor. Nevertheless, we will only discuss why MBA? In the previous blogs, we have already discussed why Masters? 

"Pursuing an MBA after engineering is a current trend in the generation. Research has proved that most of the engineering students crack the entrance exam easily compared to other departments." This is due to an engineering student study various subjects with broader context including strong aptitude and verbal skills. 

MBA is a management course which provides you to enhance your managerial skills and become a complete person with unique qualities. The course is divided into several categories like Finance, Human resource management, Marketing, Sales, Operation management, Supply chain, etc. By doing any specific course from these will brace your management skills for the same. Moreover, companies require a candidate with not only one specific quality; however, it should be multi-dimensional. In other words, the organizations are looking for a candidate who can lead the company as a leader while carrying the management skills. Hence, the candidate also requires management skills despite the technical background. Following reasons are listed:

1. An MBA course will help you to develop managerial skills, and thus, make you prepare to lead the company in management roles.

2. An engineer who wants to move up the hierarchy of the company transits from the technical role to the managerial role.

3. Engineers are flexible to convert the business into a profitable venture by there leadership qualities and entrepreneurship.

4. Engineer needs to go beyond and help the industries to create products and market them for the worth of it. 

5. It will help an engineering student to climb the corporate world with management skills.

6. An engineer can easily transit from the technical to the managerial roles. 

7. Finally, it helps the candidate to become more extrovert and develop your personality, communication skills and, etc. 

An engineer can lead the higher managerial positions with ease compared to other depts as they are technically sound with engineering depts. In addition, it also useful to do MBA after you have job experience of 2-3 years because of significant universities require a candidate with work experience. This decision is made because the ability of the person with some working experience to interact, discuss and handle a specific situation will always possess a more practical approach than a fresher candidate. In conclusion, it is an excellent option to go for if you are interested in the field of management. 

"The engineer is likely to be the manager that has to implement new practices and new technology."

 

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Why there are different lights on the aircraft?

Welcome to today’s blog.....

Let us discuss what is the function of lights on the aircraft? Why there are different lights?

Everybody who had travelled in the flight has probably seen lights on the wings, tail, nose wheel, etc. In total, there are 8 different lights on the aircraft body with corresponding meanings. 

Beginning from the front to aft: 

1 Nose wheel: This light is for the taxi and take-off light. This light helps an aircraft while taking off and taxing the plane. It is used as a signboard for the ground crew that the aircraft has received clearance to take off/land.

2. Runway lights: This light is used for lighting up the runway exits and tight turns on taxiways. 

3. Wing lights: The purpose of this light is to light up the leading edge of the wing and the area of engines. More explicitly, the pilots can check using the lights if there is damage on the wings/engine inlet and the plane can be easily visible.

4. Anti-collision light (Next to the wing in middle body bottom side): This light is used for the attention of ATC and other plane pilots that the plane is moving, This also provides the ground crew an indication that the pilot will start the engines. 

5. Landing lights (Bottom of the wing): This light is used to make the plane more visible for others that the plane is approaching the runway. It is usually switched on around 10000 feet. 

6. Position lights (On the end/side of the wing and the tail): Right sidelight is green whereas red on the left with a wide-angle of 110 degrees, in addition, a white light on the tail with 140 degrees aperture. This allows other pilots to detect/visualize the direction of an aircraft. 

7. Strobe lights ( On the wing and tail): These lights are high-intensity lights with double blinks every 2 secs. This helps the ATC and other flights to carry out the attention of the flight because might there would be another aircraft to land on the same runway. 

8. Logo lights: This light is pointed towards the company logo on the tail horizontal stabilizer. Used for advertisement and safety towards pointing the aircraft on the runway. 

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How are industries transforming?

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Let us discuss the framework about the industries and the transformation in the present scenario. What companies are looking for as an employee?

Nowadays, most of the industries are shifting towards automation, green energy and sustainability. The industries are implementing advanced systems to reduce human error, time optimization, better efficiency, less waste material (scrap) and effectiveness. These issues are trending issues in the current scenario, and industries are shifting there way toward them. For instance, Apple wants to reduce E-Waste and decrease their carbon footprints by 2030, so they decided not to provide a charger and earphones with newly released models. We should also take into account these issues are critical because it affects our surrounding environment.  

Fully autonomous is not yet possible/reliable as of now; however, companies are trying step by step to reach the highest level of autonomy. For example, Tesla is working on Autonomous level 4, which does not account for human intervention. Nevertheless, in any unwanted situation, the human driver can take the controls manually. Consequently, the industries are also looking for a candidate who is familiar with new trending topics/modules. As a company they want an employee to have some necessary qualities: Should be open to learning, familiar with new topics, possess programming skills, know how to work with hardware & system interactions and open to feedback and communication. 

"Most of us have a perception that what we study will be applied."

Not True

Considering a graduate in Engineering (CS, Mech, EEE/ECE. IT), we want to work in dept related jobs/core work; however, all of us do not get the opportunity for the same. In the following steps, we will discuss how to shape a career based on the current trending topics. Currently, new fields are Artificial intelligence, autonomous cars, hybrid vehicles, driver modelling, cooperative driving. All of these topics prerequisite knowledge in programming, mathematics, modelling systems, etc. To be connected with one of the current topics, we should indulge ourself with technology by learning new aspects about it. 

1) After, graduation in the above-mentioned depts you want to pursue your career in the new trending research/topics.

2) First of all, you should brace your profile for a suitable position which can be done by applying for certifications for the specific courses online.

For certifications go and join: https://nptel.ac.in/ and/or  https://www.coursera.org/  

and/or https://www.udemy.com/ 

3) Learn new software and/or currently used by companies for the analysis of systems such as python, MATLAB, Adams, etc.

4) Python and MATLAB are one of the trending computation software in the current tenure, and most of the applications are built based on them.  

5) Stay connected with new technological updates, for instance, if you are a car enthusiast stay updated with recent technology and the software being used by the companies for the same. 

 "Never dream about it work for it."

Most of the universities have started their undergraduate courses for the same topics because the future is curving towards them. This decision of universities will transform the future and aspirants to work in these trending topics. In coming 20-30 years, we will be surrounded by the autonomous world such as robots at industries, flying cars, etc. 

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What is Carnot Cycle or Heat Engine?

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Let us discuss what the Carnot Cycle is? We have already discussed some basic thermodynamic processes and their applications. Thermodynamics is one of the most researched topics in the field of Mechanical Engineering. The field of thermodynamics provides you with extensive knowledge about Heat and Mass, Power Plants, I.C Engines and related applications.

The Carnot Cycle is the theoretical ideal thermodynamic cycle proposed by French Scientist. However, it is not an actual thermodynamic cycle, but it provides an upper limit on the efficiency that any classical thermodynamic engine can achieve. In other words, the Carnot cycle is a hypothetical heat engine which can provide maximum efficiency between the specified temp range. The Carnot cycle is an ideal reversible closed cycle in there are four thermodynamic processes are involved, i.e. isothermal expansion, adiabatic expansion, isothermal compression and adiabatic compression. 

These four processes build a closed thermodynamic cycle, the P-V diagram of the cycle is shown in the above figure: 1-2 and 3-4 are the constant temp processes, and 2-3 and 4-1 are adiabatic processes means no heat exchange. 

Isothermal Expansion: Heat is transferred at a constant temp and the gas is allowed to expand due to which the pressure drops from point p1 to p2, but the temp remains the same because it has thermal contact. Thus the gas can expand within the system so-called as Isothermal expansion.

Adiabatic Expansion: As the gas is in thermal contact, no exchange of heat takes place, but the pressure drop from point p2 to p3, as the gas continues to expand. The work is done the system and losses the internal energy equal to the amount of work done. 

Isothermal Compression: Now the gas comes in contact with low temp reservoir and the surroundings do work on the gas; thus, the pressure rise from p3 to p4. However, there is no exchange of heat, so the temp remains constant. 

Adiabatic Compression: In this case, the system come back to its ideal state by work, increases the internal energy of the system and causing the temp to rise without any exchange of heat in the process. Due to the effect of compression, the pressure of the gas rises up from p4 to p1. 

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What is new in GATE 2021?

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Let's discuss what is new about GATE 2021? In the previous, we have already discussed: what is GATE, how to prepare and how to revise effectively.

Yesterday, IIT Bombay announced the exam date, new rules for the exam, eligibility criteria and including two new subjects. As per the meeting reports, the exam 2021 is to be conducted between February 5-7 and February 12-13. The eligibility rules proclaim the third-year student of Bachelors in Engineering can also apply for the exam 2021 owing to the pandemic situation (Which was not the case before). In addition, the committee also decided to ease the process of exam considering the condition of students who will pass in the upcoming year (Still in the process). In my perspective, this decision will help a lot of aspirants those who are willing to join IIT's and NITs for the Masters or PhD scholar.

Next, the IIT Bombay committee announced two new subjects for the GATE 2021, which are Environmental Science, and Humanities & Social science and/or General Studies. I would say it is an excellent decision to add these subjects in the exam as per the requirement in industrial/professional field. Because every one of us feels the industries still use traditional methods which is a myth. Nowadays, companies are looking for a candidate who is flexible with any course, knows current trending topics and the one who can leverage the company demand. These topics were already in the syllabus of Engineering Services Exam (ESE), and it is virtuous to study the trending topics in the present scenario because you will get to learn the fundamentals and future research topics. Based on the research, the syllabus for both these topics would be similar to the ESE exam with less content than the ESE exam.

From personal my experience, an Engineer is good at Maths, Engineering subjects, Aptitude, Science subjects, but they are undoubtedly weak or not interested in studying General Studies, Environmental aspects, Ethics and other related subjects. However, those who want to prepare for either ESE and/or IAS these subjects have most weightage in the exam, which also helps an Engineering student to get aware of these topics. That is what I feel makes you a complete 3-dimensional person with unique capabilities. These exams (ESE or IAS) provide you with the first-class govt. Jobs; thus, they require a unique candidate. Hence, that could be one of the reasons the GATE committee indulged those two subjects in GATE 2021. This move/step will help the new generation/students to find new career opportunities in various depts related to Engineering research,science, forestry, social science areas.

 

For more details: Check the official website and/or stay tuned with the blogs.

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Does an Aircraft have Anti-Skid System?

Welcome to today's blog...

Let's talk about what is an ABS system?

Antilock-Braking system is equipped in the cars to prevent unnecessary locking of the wheels while driving, or under any unwanted situation and on a wet surface. This safety equipment ensures the safety of the vehicle and prevents the vehicle from losing its stability. Even an aircraft has a similar system to prevent the life of passengers and aircrew. 

An aircraft possess multiple disc brakes made up of carbon fibres which consist of a stator (rotary part) and a carbon fibre disc on the rotary, as shown in the figure below. This generates the friction in between the two while rotation; thus, the speed is reduced or deacceleration is obtained. The carbon fibre is used over steel brakes due to efficient performance as it posses lower weight and high capability of absorbing energy whereas, the steel brakes are smaller in size and have more wear & tear as compared to carbon fibres. They are cost-effective, lighter weight, longer life and helps in fuel saving.  

Braking action also incorporates slip movement in action consider there is 10% slip in a stretch of 20 m, which means the aircraft covers 18 m. Whereas in the case of 100% slip with maximum brake pressure, the wheels will lock, and the tires start to skid. The slipping of tires is defined as the abrasion of tires when in contact with the runway. This condition of sliding/skidding can lead to blow out of tire due to extreme friction between the contact surface (runaway and tires), which might also turn into a loss of aircraft stability. 

Therefore, to prevent these unwanted situations, the aircraft is enabled with Anti-Skid System. This system works similar to the ABS system in cars, which prevent the wheels to lock by continuously braking them through electronic control systems. In the aircraft, the wheels are equipped with sensors and hydraulic valves which takes control over this type of unwanted situations. The primary function of the wheel sensor is to ensure whether the wheels have touched down the runway and they are spinning. If not, you cannot apply the brake pressure to prevent the wheels from getting lock before touching the runway. Secondly, the sensor monitors the wheel speed to prevent skidding/sliding. If there is a situation of the wheels are locked the valve release the pressure so that the wheels can spin and then apply the brake pressure to brake the wheels, hence, to switch off the Anti-skid system.

Consider a wet runway the technology of Anti-Skid system will help the aircraft to brake efficiently as the friction coefficient reduces and there is a less braking effect. In general, after an aircraft reaches a speed of about 85 knots (~ 43.7 m/s) the Anti-Skid system automatically switches on because there might be a need to brake an aircraft while taking off due to some technical faults/malfunction. 

Wheel Hub

Hope you find it interesting. Thanks for reading it.........