Category: For 1st yearites

Supplements for Trical 1st Year & 2nd Year students

by rahulin Electrical, For 1st yearites, For 2nd yearites, InternshipLeave a Comment on Supplements for Trical 1st Year & 2nd Year students
Reading Time: 2 minutes

Electrical engineering is one of the pioneers in modern development. This branch has its origin dated

back to the times when magnetism and electricity were discovered. Today, it provides the 4th

requirement of humans after air, water and food- electricity. It is known as the mother branch of

Electronics, Communication and Computer Science.

 

• Broad classification of Electrical Engineering-

 1. Power System- It deals with the generation, transmission, distribution of electric

power. Moreover, it deals with stability and fault analysis of electrical lines.

If possible, visit a power plant.

 2. Control and Optimization- It deals with control systems which regulates almost

every machine and process. For example, to regulate a movement of robotic arm,

the design of complete system comes under this subject. This is a subject for you

if you are interested in Mathematics. This subject along with Microcontrollers,

forms the exciting automation subject (which is present in almost every modern

equipment). For further reference:www-control.eng.cam.ac.uk

 3. Power electronics- When electronics is applied for power conversion. This forms

integral part of modern power system. (If you are fascinated by inverter made by

Rancho in 3 idiots, then this is the subject for you)

 4. Machines- A subject of imagination. I don’t think you need description for this

subject

 5. Electrical Circuits- This part will serve as a basis for all the subjects described above.

 6. Microprocessor, Microcontrollers and Embedded System- If you are fond of

electronics and programming, these courses are for you. Almost every appliance

uses embedded system, for its control and operation.

 

• Things to do in summer –

 1. Visit a motor rewinding workshop. It will give you real insight of windings in

electrical machine. It will definitely serve as a base for subjects like Electrical

Machine 1 & 2. Moreover there is no prior permission required, you can just go

there, give your introduction and ask them to explain you the windings of machine.

 2. Do not ignore MATHEMATICS. There are many subjects in Electrical Engineering

which heavily rely on calculus and linear algebra. If you love to study apart from

your normal curriculum, there are online courses of calculus and linear algebra on

following website:ocw.mit.edu

 3. Probably everyone related to engineering has given this advice- Learn C

programming. And I am sure that majority of you have ignored it. I will just say-

If you want to peacefully clear your engineering, sit down in your room, watch

movie- The Social Network, get some motivation for programming, and learn C

programming. I know this is hard, but sometimes we don’t have options.

CRYOGENICS : Basics & Applications

by Arvindin For 1st yearites, For 2nd yearites, Mechanical2 Comments on CRYOGENICS : Basics & Applications
Reading Time: 7 minutes

 

 

 

TABLE OF CONTENT

  • INTRODUCTION
  • CRYO—-
  • TYPES OF CRYOGENIC TREATMENTS
  • ABSOLUTE ZERO
  • PRODUCTION OF LOW TEMP
  • METHODS OF LIQUIFICATION OF AIR
  • APPLICATIONS
  • CRYOGENS
  • CONCLUSION
  • CRYOGENIC LABORATORY

 

INTRODUCTION

  • Cryogenics – the study and use of materials at extremely low temperatures
  • Inputs from three major disciplines, namely PHYSICS , MECHANICAL ENGINEERING, CHEMICAL ENGINEERING
  •  Such low temperatures cause changes in the physical   properties of materials that allow them to be used in unusual engineering, industrial, and medical applications
  •  For example, in the cryogenic temperature range, air becomes a liquid—or even a solid—and living tissue freezes instantly

 

TYPES OF CRYOGENIC TREATMENT

  •  SHALLOW CRYOGENICS, the objects are cooled down to temperature of approximately -85oC
  • FLOODING, first the object is taken to -85oC, then the chamber is flooded with liquid nitrogen to reduce the temperature furthur
  • DEEP CRYOGENICS TREATMENT, Subjects the objects to the temperature of approximately    -185oC

 

ABSOLUTE ZERO

  • Absolute zero is a temperature marked by a 0 entropy configuration. It is the coldest temperature theoretically possible and cannot be reached by artificial or natural means

 

PRODUCTION OF LOW TEMPERATURE

  • HEAT CONDUCTION: When bodies are in contact, heat flows from the body with the higher temperature to the body with a lower temperature. Can occur between any and all forms of matter. It is essential in the production of cryogenic temperatures and environments.
  • EVAPORATIVE COOLING: Humans lose heat by this mechanism. Atoms and molecules in the gaseous state are moving faster than the atoms and molecules in the liquid state. Adding heat energy to the particles in a liquid makes them gaseous
  • THE JOULE-THOMSON EFFECT:  Allowing a gas to expand very rapidly causes its temperature to drop dramatically. Reducing the pressure on a gas accomplishes the same effect.
  • Ordinary house hold refrigerators and air conditioners operate on this principle.

 

METHODS OF LIQUIFICATION OF AIR

  • Linde’s System also known as Hampson System
  • Claude’s System

LINDE’S SYSTEM

 

 

6

 

  • Clean dry air is taken from the atmosphere and is compressed up to 200 bar
  • The high pressure enters into counter flow air to air heat exchanger and is then throttled to atm – pressure
  • The J-T cooling up to expansion causes a lowering of temperature and this cool air is passed through heat exchanger where it cools the incoming high section
  • Thus the temperature at the valve is progressively lowered until the liquefaction temperature is reached

 

CLAUDE’S SYSTEM DIAGRAM

 

5

  • Claude’s System yields more efficient cycle than Linde’s System
  • The expansion through an expansion valve is an irreversible process.
  • In Claude’s System energy is removed from the gas stream by using an expansion engine or expander.
  • The expansion process is isentropic and much lower temp is attained then isenthalpic expansion
  • In Claude’s System the gas is first compressed to pressure of the order 4 Mpa.

 

How Claude’s System is more efficient than Linde’s System

  • The advantage of the Claude’s System is, it operates at low compression ratio      compared with Linde’s process.
  • Secondly the temperature of air before coming to the expansion valve in Claude system is lower than the Linde system.

 

Cryogenic Devices

4

 

3

 

 

2

 

APPLICATION OF CRYOGENICS

  •   Aerospace-cryogenic engines
  •  Medical Field
  •  Manufacturing field
  •  Electronics Field
  •  Fuels research
  •  Miscellaneous uses

 

CRYOGENIC ENGINES IN AEROSPACE

  • First operational Cryogenic Rocket Engine is 1961 NASA designed  RL-10 LOX LH2 rocket engine
  • The second-stage Pratt & Whitney RL10B-2 engine is based on the 30-year heritage of the reliable RL10 engine
  • At Mahendragiri in Tamil Nadu, is the LPSC. The system involves materials working at 23K and pumps at speeds of 40,000 rpm. Complex metering, monitoring, integrating technologies involved. The engines required to fire for  700 seconds during the final stage of a launch providing 7 tones of thrust
  • Engine works on ‘Staged Combustion Cycle’ with an integrated turbo pump running at 42,000rpm. Also equipped with two steering engines developing a thrust of 2 kN each to enable three-axis control of the launch vehicle during the mission
  • Closed loop control of both thrust and mixture ratio, which ensures optimum propellant utilization for the mission
  • To know how cyrogenics plays vital role in space shuttle.. watch this video :

              https://www.youtube.com/watch?v=LjG-4oR7JxI

 

CRYOSURGERY

  • Cryosurgery- Use of extreme cold produced by liquid nitrogen (or argon gas) to destroy abnormal tissue.
  • Used to treat external tumors, such as those on the skin.
  • For internal tumors, liquid nitrogen is circulated through a hollow instrument called a Cryoprobe.
  • Used since many years in the treatment of skin cancer

 

CRYOGENICS IN MANUFACTURING FIELD

  • Cryogenic treatment works on Reamers, Tool bits, Tool punches, Carbide Drills, Carbide Cutters, Milling Cutters, Files, Knives, Reciprocating Blades, Dies and cutting tools
  • Stress relieved ferrous and non ferrous castings and forgings for enhanced dimensional stability and surface finish

 

CRYOGENICS IN ELECTRONICS FIELD

  • Super conducting electronic devices like SQUID (Super conducting quantum interference device) are used in sensitive digital magnetometers and voltmeters
  • Zero friction bearings use magnetic field instead of oil or air, derived from the Meissner Effect associated with super conductivity.
  • Super conducting electric motors are constructed approaching zero electric loses

Nuclear Magnetic Resonance Spectroscopy (NMR)

Most common method to determine the physical and chemical properties of atoms by detecting the radio frequency absorbed and subsequent relaxation of nuclei in a magnetic field. Strong magnetic fields are generated by supercooling electromagnets. Liquid helium(BP  4K) is used to cool the inner coils. Cheap metallic superconductors can be used for the coil wiring. So-called high-temperature superconducting compounds can be made to superconduct with the use of liquid nitrogen(BP 77K)

Magnetic Resonance Imaging (MRI)  :

Complex application of NMR where geometry of the resonances is deconvoluted and used to image objects by detecting the relaxation of protons that have been perturbed by a radio-frequency pulse in the strong magnetic field. Mostly used in health applications

Electric Power Transmission:

  • Superconductors could be used to increase power throughput. Require cryogenic liquids such as nitrogen or helium to cool special alloy-containing cables to increase power transmission. Field is the subject of an agreement within the International Energy Agency.

Frozen Food:

  • Transportation of large masses of frozen food. Food is freezed in war zones, earthquake hit regions, etc. Cryogenic food freezing is also helpful for large scale food processing industries

Forward looking infrared (FLIR)
Many infra-red cameras require their detectors to be cryogenically cooled

 

Blood banking
Certain rare blood groups are stored at low temperatures, such as −165 °C

Special effects
Liquid nitrogen and CO2 has been built into nightclub effect systems by Kryogenifex to create a chilling effect and white fog that can be illuminated with colored lights.

 

 

 1

  • Inert Gases: Do not react chemically to any great extent. Do not burn or support combustion. Includes Nitrogen, Helium, Neon, Argon and Krypton
  • Flammable Gases: Some cryogenic liquids produce a gas that can burn in air. Includes Hydrogen, Methane and Liquefied Natural Gas
  • Oxygen: Many non-combustible materials can burn in the presence of Liquid Oxygen. Organic materials react explosively with Liquid Oxygen. Hazards and handling precautions of liquid oxygen is considered separately from other cryogenic liquids

 

FACILITIES AT OUR CRYOGENICS LABORATORY

  • Oil Diffusion Vacuum Pumping System with Measuring Guages, Trolley Heater & Oil
  • Dewar vessels ( Model T-26-A 0110 capacity – 25 Lt. ) ( Model T-55-A 0110 capacity – 50 Lt. )
  • VPF 100 Liquid Nitrogen variable temperature Dewar with Controller & Trolley
  • Servotronic Digital (6 digit) Temperature Indicator ( PT-100 -200C to 100C six channel 230 VAC )
  • Piezo-Electric Transducer with Accessories
  • Data Logger with Software for online display ( ModelNo: MICROLOG 6102 + CST 27)
  • Helium Compressor

 

Projects on Cryogenics

  • QUASI-ISOTHERMAL EXPANSION ENGINE FOR CRYOGENIC AUTOMOTIVE PROPULSION
  • CRYOGENIC ENGINE IN ROCKET PROPULSION
  • DEEP SPACE COOLING TO ELIMINATE CRYOGENIC VENTING
  • APPLICATION OF CRYOTREATMENT FOR ENHANCEMENT IN TOOL LIFE

Supplements for 1st and 2nd Year Chemies

by abhishekin Chemi, For 1st yearites, For 2nd yearites, InternshipLeave a Comment on Supplements for 1st and 2nd Year Chemies
Reading Time: 4 minutes

Hey 2nd Yearites . !!  As you are in 4th sem so first of all you might be thinking  what chemical engineering is…. We are not definitely studying it the way we used to study chemistry in XI or XII standard,instead of that we are with subjects like Electrical Technology, TMMD, Solid mechanics. I’ll tell you why these subjects are important. As chemical engineer you will be able to come up with technical solutions for problems and issues in relation to process and product technology. In finding these solutions, chemical engineers work closely with experts from other specializations, taking into account the related economical, social, environmental and ethical aspects of the problem they’re dealing with. To understand it let us see one practical situation wherein you have task to build up a transportation pipeline from point A to point B  and no qualified person is with you to help except one or two labourers. Your area of concern will be : 1) Angle of elevation of point A and point B from horizontal. 2) Diameter,length of pipe and which type of joints should be there? — So here comes Theory of machines and machine designing. 3) From what material pipe is to be made ? and what are the possibilities of failure of such a  structure? If pipeline is to be made underground then the nature of soil needs to be understood to avoid corrosion problems— So here comes Chemical Engineering Materials. Finally let’s say you have carefully made all arrangements and the pipeline is ready to use. And as you switch on the pump, you may not see the fluid coming out from the pipe!!Then what will you do??? What is the problem??? Problem was that you may not used proper motor which will provide you exact power or you have purchased correct HP motor but it is consuming more power, then you will go and see whether my motor is delta or star connected because every connection has its advantages and disadvantages. So if you have studied electrical engineering basics then you would have easily identified the problem.

  • Please don’t take any subject lightly or for the sake of getting marks. Strictly speaking what I think  from my experience is that an engineer should have the know of  basics of all disciplines of engineering. Now you may ask is coding and programming is going to help a chemie?? The answer is yes, because chemical process calculations are not as simple as solving an two variable equation and finding the answers. Practically any chemical  process or  even a small unit operation will have ‘n’ no. of variables so how you can solve them. So we need simulation software to handle these large no of variables. Now if you have basic “funda” clear in your mind that how it was designed and programmed.. You can handle the software much better than your colleague. But again I am not saying that you should be ‘phoodu’ in programming but basics are compulsory.
  • So, Chemical or process engineering is an interdisciplinary science comprising elements of mechanical Engineering, chemistry and technical physics.
  • The difference between chemical Engineering and process engineering lies in the emphasis of the degree course: while chemical engineers concentrate mainly on chemical processes, process Engineers deal primarily with the plants needed for this, their design and technical solution.
  • For General Chemical Technology (GCT) please watch you tube animation videos, NPTEL lectures. Also you can distribute these topics among your friends and then have a discussion for e.g. one can prepare about paper and pulp industry , other one on sugar industry and discuss among themselves.

I hope you are clear what are the application and importance of these subjects in the life of chemical engineer.

  • For first yearites : Observe the chemical processes occurring in day to day life and analyze them. See corrosion problems , how thermodynamics is playing in your home kitchen, analyze how propulsion systems works , analyze how energy sources like batteries, fuel cells, solar cells works.
  • Study alternate sources of energies such as bio diesel ( Jatropha seeds).Go through some basic outline of industries such as:Sugar industry, paper and pulp industry, soap and detergent industry….etc.
  • If possible visit as many industries as possible.
  • At the end of first year try to learn Microsoft Excel Software as much you can and C programming language in summer vacations.

 

  • For second yearites.. We dont have core chemical engineering subjects in 2nd year… So in 2nd year have active  participation  in techfests of various colleges; this will give you experience, direction , boost up your confidence and   will definately gives practical knowledge which helps when you will study core subjects such as (HTO, MTO, Thermo, CRE..etc)
  • You can participate in events like chemical car competition and chemistry related quizzes in 2nd yearand then in 3rd year you can participate in heat exchanger event …(I am saying this because there is a separate topic on heat echanger in 5th semester,so it is better to participate in this event later on in 3rd year.) … Do as per your interest.
  • Read magazines these are available in library, watch NPTEL lectures they are very good.
  • There are some free online courses available online these are given by profs of MIT , Harvard, Oxford, Stanford.. So make use of them. Most recommended courses are EDX and Stanford university online course.
  • My advice to you all is that don’t do industrial training in 2nd year.Instead  go to your seniors, profs and work under them  and learn as much you can from them. The best places for summer training  in chemical engineering some are: IITs, IISC , ISER, NCL, ICT, CSMCRI etc and in Private colleges we have very good Nanotechnology Lab at DDIT college in Nadiad. and in our college itself we have summer training programme so apply for that .

Some preferred courses: EDX

  1. our energetic earth
  2. Introduction to water treatment 
  3. Solar energy
  4. Introduction to solid state chemistry
  5. Thermodynamics

  6. Introduction to Drinking Water Treatment

STANFORD ONLINE COURSE

  1. Solar: Solar Cells, Fuel Cells and Batteries.
  2. Reservoir Geomechanics

Cellular Communication

by dhavalin For 1st yearites, For 2nd yearites, TronicsLeave a Comment on Cellular Communication
Reading Time: 6 minutes
OUTLINE:-
Electromagnetic Spectrum.
Why Micro-waves?
Why Cellular?-Frequency Reuse.
Basic Structure.
How do you call your friends?
Hand-off
Spectrum crunch
Cognitive radio
Cell breathing
Green communication.
Research in this domain.
Why micro-waves?

Microwaves are widely used

for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna.
Less attenuation to water vapour,oxygen molecules,etc.

Range roughly from 800MHz-30GHz

FREQUENCY REUSE:- 
}Method used by service providers to improve the efficiency of a cellular network and to serve millions of subscribers using a limited radio spectrum.
}Based on the fact that after a distance a radio wave gets attenuated and the signal falls bellow a point where it can no longer be used or cause any interference.
}Transmitter transmitting in a specific frequency range will have only a limited coverage area
}Beyond coverage area frequency is reused by another transmitter.
}the entire network coverage area is divided into cells based on the principle of frequency reuse

Cells

• basic geographical unit of a cellular network
• Represented graphically as a hexagonal shape, but in reality it is irregular in shape
• Width of cells changes as demand changes.

Cluster

• is a group of adjacent cells, usually 7 cells; no frequency reuse is done within a cluster.
BTS (Base Transceiver Station)
• Main component of a cell
• Connects the subscribers to the cellular network
•Transmission/reception of information; it uses several antennas spread across the cell
 
BSC (Basic Station Controller)
• Interface between BTSs and it is linked to BTSs by cable or microwave links; it routes calls between BTSs; it is also connected to the MSC
MSC (Mobile Switching Center)
• Coordinator of a cellular network
• Connected to several BSCs,
• Routes calls between BSCs;
• Links the cellular network with other networks like PSTN through fiber optics, microwave or copper cable

 Home Location Register (HLR)

– maintained by the service provider

– permanent data about each subscriber (i.e. location, activity status, account status, call forwarding preference, caller identification preference)

  Visitor Location Register(VLR)

–stores temporary data about a subscriber; it is kept in the MSC of the of the area the subscriber is located in; when the subscriber moves to a new area the new MSC requests this VLR from the HLR of the old MSC

 Equipment Identity Register(EIR) –

-database located near the MSC and containing information identifying cell phones which are stolen or which are cloned.

Authentication unit:-

-This unit holds the security concerns that hover around the all channels, authenticating even the correct base station not the ones held for data recovery by some external agents.

Control channel

-dedicated channel for sending ack,tracking call,tracking messages,other control signals

-only control data ;no voice

Voice channel

-for only voice transmission

 

 

CALLING & RECEIVING :-

-the subscriber dials the receiver’s number and sends it to the BTS
-the BTS sends to its BSC the ID, location and number of the caller and also the number of the receiver
-the BSC forwards this information to its MSC
-the MSC routes the call to the receiver’s MSC which is then sent to the receiver’s BSC and then to its BTS
-the communication with the receiver’s cell phone is established
-when the receiver’ phone is in an idle state it listens for the control channel of its BTS
-if there is an incoming call the BSC and BTS sends a message to the cells in the area where the receiver’s phone is located
-the phone monitors its message and compares the number from the message with its own
-if the numbers matches the cell phone sends an acknowledgement to the BTS
after authentication, the communication is established between the caller and the receiver
-when the phone needs to make a call it sends an access request (containing phone identification, number) ; if another cell phone tries to send an access request at the same time the messages might get corrupted, in this case both cell phones wait a random time interval before trying to send again
-then the BTS authenticates the cell phone and sends an acknowledgement to the cell phone
-the BTS assigns a specific voice channel and time slot to the cell phone and transmits the cell phone request to the MSC via BSC
-the MSC queries HLR and VLR and based on the information obtained it routes the call to the receiver’s BSC and BTS
 the cell phone uses the voice channel and time slot assigned to it by the BTS to communicate with the receiver.

 

 

Calling & Receiving Continued:-

-When a request to deliver a call is made in the network, the MSC or the receiver’s home area queries the HLR; if the cell phone is located in its home area the call is transferred to the receiver; if the cell phone is located outside its home area, the HLR maintains a record of the VLR attached to the cell phone

– Based on this record, the MSC notes the location of the VLR and indicated the corresponding BSC about the incoming call

-The BSC routes the call to the particular BTS which uses the paging channel to alert the phone.

-The receiver cell phone monitors the paging channel periodically and once it receives the call alert from the BTS it responds to the BTS

-The BTS communicates a channel and a time slot for the cell phone to communicate

– Now the call is established

 

 

HAND-OFFS:-

-Why Hand-off?
-How to do Hand-off?
-What factors determine handoff?
-Types of hand-off
First generation Hand-off
MAHO-In 2g phones
First generation Hand-off:-
-In this signal strength measurements are made by base station & supervised by MSC.
-Each base station monitors the signal strengths of all the control channels to determine the relative location of each      mobile user with respect to the base station tower.
 The locator receiver is controlled by the MSC & is used to monitor the signal strength of users in need of hand-off.
  Based on the locator receiver signal strength info from each base station ,the MSC decides whether hand-off is      necessary or not.
MAHO-In 2g phones:-
Every mobile station measures the received power from surrounding base stations &  continually reports the results to these measurements to the serving base station.
A hand-off is initiated when power received from base station of a neighbouring cell begins to exceed the power received from current base station by a certain level or for a certain period of time.
Advantage………….
Cell breathing:-

is a mechanism which allows overloaded cells to offload subscriber traffic to neighbouring cells by changing the geographic size of their service area. Heavily loaded cells decrease in size while neighbouring cells increase their service area to compensate. Thus, some traffic is handed off from the overloaded cell to neighbouring cells, resulting in load balancing.

 

 

Why green Communication?

-Use of solar panels in place of diesel in base station.

-Dynamic Power Assignment based on load detection,

-A fixed control channel scans number of mobile users in an area of a cell & tells neighbouring bts whether or not to expand.

-if the minimum requirement fails then bts expand & area is served by that neighbouring bts. While the bts of that cell remains off.

 

RESEARCH IN THIS DOMAIN:-

Methods for Efficient Hand-off with same quality of service. (QOS)
Tackling Spectrum Crunch – Software defined Radio-cognitive radio.
Maintaining the QOS within a cell at specified power level.
Security in software defined radio.
Green wireless communication-focussing cell breathing techniques even in high traffic zones.
THINGS YOU NEED TO KNOW:-
Basic electronics.(1st year).-Websearch.
Signal & System.(2nd year).-Prof.S.C Dutta Roy IITD NPTEL
Analog Modulation.(2rd year)-Prof. Surendra Prasad IITD NPTEL
Digital Modulation.(3rd Year)-Taub –Communication Engineering.
Speech Coding(no year)-Rabiner;Rappaport;Youtube-E amberkairajah-video.
Wireless Communication(Final Year).-Rappaport;Prof.Ranjan K Bose-IITD NPTEL
Advanced 3G 4g NPTEL-IIT KANPUR
REFERENCES:-
Wireless Communication “Rappaport”-Pearson Publications.
NPTEL Videos-Prof.Ranjan K Bose-IIT Delhi.
IEEE Papers.
https://www.youtube.com/watch?v=KymIDyQiXZI-basic building block call transfer Mr. Vishwendra Choudhary.

 

Download materials:-

CELLULAR COMMUNICATION

Basic Communication:-

Types of Hand-offs:-

 

SATELLITES : ENGINEERING EXCELLENCE

by Kaustubh Singhin For 1st yearites, For 2nd yearites, TronicsLeave a Comment on SATELLITES : ENGINEERING EXCELLENCE
Reading Time: 6 minutes
GPS-IIRM
SATELLITE ORBITING EARTH
Ref : Google Images


                                                       
A satellite is one of the most complex machines ever built by mankind. It is a great challenge to make a satellite because of the harsh conditions of space, the shock waves, vibrations of launch, the varying temperatures (from -250 degrees to > 100 degrees warm), making adjustments in the orbit and dealing with space debris, solar flare and radiation, making it last for about 5-10 years. Sophisticated electronics are used which can withstand these harsh conditions, Apart from it there are no repair/ reservice  options either – one part damaged or malfunctioned , then goodbye satellite forever..!!

sat1
COMMUNICATION OF GROUND STATIONS THROUGH SATELLITE
Ref : Google Images

It has its own communication system module often termed as payload to receive the signal from earth (UPLINK) and filters the signal from noisy components, amplify it and send it back to earth where an antenna receives the signal (DOWNLINK). It does this work with the help of a transponder, which is an integrated radio signal receiver and antenna. The frequency is generated by a quartz resonator, which is the heart of satellite.

 

Classification of Satellites :

Satellites are orbiting the earth in three different orbits : Low Earth Orbit (LEO), Medium Earth Orbit (MEO) and Geosynchronus Earth Orbit(GEO).LEO satellites work at an altitude between 160 km and 1,600 km  above Earth. MEO satellites operate from 10,000 to 20,000 km .GEO satellites are positioned 35,786 km (22,236 miles) above Earth and they complete one orbit in 24 hours.

earth-orbits1
LEO, MEO AND GEO SATELLITE ORIENTATION AROUND EARTH
Ref : Google images

LEO Satellites

  • Advantages:
    • Reduces transmission delay
    • Eliminates need for bulky receiving equipment.
  • Disadvantages:Subdivisions: Little, Big, and Mega (Super) LEOs.
    • Smaller coverage area.
    • Shorter life span (5-8 yrs.) than GEOs (10 yrs).

 

Little LEO Satellite

  • 0.8 GHz range
    • Small, low-cost
    • Vehicle tracking, environmental monitoring and two-way data communication. Used for short, narrowband communications.

Super LEO Satellite

  • 2 GHz or above range
  • Can offer global services, which can be subject to regulatory requirements.
  • Used for technology devices such as high-speed, high-bandwidth data communications, and video conferencing. They carry voice and high-speed data services. The main uses are data communications and real-time voice delivery to hand-held devices.

 

 

MEO Satellite :

  • MEO satellites have a larger coverage area than LEO satellites
  • A MEO satellite’s longer duration of visibility and wider footprint means fewer satellites are needed in a MEO network than a LEO network
  • A MEO satellite’s distance gives it a longer time delay and weaker signal than a LEO satellite, though not as bad as a GEO satellite

Satellite use very high frequency range of signals for effective communications. The lower GHz frequency range bands are  L band,S band, C band extending upto Ku,Ka, X and Vbands which extend upto 50GHz range. The L,S,C bands have low power and Ku,Ka, X and V bands have high power.

 

GEO Satellite :

  • Orbit is synchronous with the earth’s rotation.
  • From the ground the satellite appears fixed.
  • Altitude is about 23,000 miles.
  • Coverage to 40% of planet per satellite.
  • Geostationary satellites are commonly used for communications and weather-observation.
  • The typical service life expectancy of a geostationary satellite is 10-15 years.
  • Because geostationary satellites circle the earth at the equator, they are not able to provide coverage at the Northernmost and Southernmost latitudes.
  • Advantages:
    • Weather images can be displayed.
    • Television broadcasts are uninterrupted.
    • Used to track major developments such as hurricanes 24 hours a day.
  • Disadvantages:
    • It takes longer for the signal to get to earth and back to satellite (Delay of .22 s).
    • Increased difficulty of telephone conversations.
    • GEOs are not positioned in the farthest northern and southern orbits.
GSAT4 disassembled view
SATELLITE EXPLODE IMAGE : GSAT 4 DISASSEMBLED
Ref : Google Images

 

 

Satellite Components :

 

Bus Mainframe  :

It is the frame of the system. It contains antenna dishes, transponders, thrusters, fuel cylinders, engine, position control system,solar panels etc. It is made of aluminium and carbon fibre.

 

Command Control and Telemetry :

The station from earth monitors the health of satellite including its vital parameters continuously which ensure the satellite is operable for many years. They have a separate antenna and separate frequency to monitor and establish radio diagnostics and control (RDC).

 

Power System :

Photovoltaic cells are employed on solar panels which have a conversion rate of 20%.They power up the circuitry on board and recharge batteries. The panels are foldable and are constantly positioned for maximum collection of sunlight on panels. Apart from that on board Ni-Cd  batteries that have best power weight ratio and are used on eclipses, where shadow of the planet causes block in sunlight.

Orbital Position System:

The gravitational fields of earth and moon have effect on the orbit of the satellite. The fuel in satellite system, hydrazine is thrusted out to maintain on its elliptical path (Attitude Control System). The attitude and orbit control subsystem consists of sensors to measure vehicle orientation; control laws embedded in the flight software; and actuators (reaction wheels, thrusters) to apply the torques and forces needed to re-orient the vehicle to a desired attitude, keep the satellite in the correct orbital position and keep antennas positioning in the right directions.

Antenna and Receivers :

Every satellite has got a different range of antennas on it. Medium gain antenna , high gain antenna etc. are employed for various purposes. Different radiating power is needed for these antennas.LEO satellites need big antenna dish because of low power and low frequency and due to high frequency range of GEO satellites, need a small antenna system. They have carbon fibre skins bound on Kevlar honeycomb. They don’t have a smooth surface.

 

The Thermal Control Subsystem

The thermal control subsystem helps protect electronic equipment from extreme temperatures due to intense sunlight or the lack of sun exposure on different sides of the satellite’s body (e.g. Optical Solar Reflector).Vacuum deposited aluminium on kapton is used for thermal insulation too.

 

Transponder :

The second major module is the communication payload, which is made up of transponders. A transponder is capable of :

  • Receiving uplinked radio signals from earth satellite transmission stations (antennas).
  • Amplifying received radio signals
  • Sorting the input signals and directing the output signals through input/output signal multiplexers to the proper downlink antennas for retransmission to earth satellite receiving stations .

 

After serving its term the small thrusters fire off  the satellite using the last of on board fuel to its graveyard orbit away from earth in to the deep space.

 

satellite.2201
ENDING JOURNEY OF SATELLITE IN GRAVEYARD ORBIT
Ref : Google Images

 

 

 

Creating your own ANIMATIONS

by Som Pathakin Animation, For 1st yearites, For 2nd yearitesLeave a Comment on Creating your own ANIMATIONS
Reading Time: 2 minutes

Have you ever dreamt how Optimus Prime from TRANSFORMERS look so realistic , how the animation of PIXAR  is  so  pragmatic ?

Why these HOLLYWOOD people manage to produce such a high quality graphics for their work? Is there something magical with them, perhaps yes, they have with them the best team of computer artistic with their powerful software.

AUTODESK 3DS MAX is one of the software which is widely used in film industries. It is one of the most powerful tools which could transform your creative ideas into your movie screen and animations. Even if you are not a good programmer you can smoothly start with 3ds max to run you creative ideas.

To start with 3ds max you have to create a basic  3d structure for your  object , this process is known as MODELING , there are various (plane box) modeling technique provided by  3DS  to convert  your simple 2D image into 3D model . For this you need to have top view, side view, front view of the model (I know its scaring 1st Yr Engg. Drawing again .. phew..!!)

After creating your basic 3D structure, you apply  rigging to your object , which means to define  your object movements and  prepare your object for animation and finally apply animation to it. There are many steps involved in this process before you get you final output which involves adding UV to your object, rendering your scenes ,enveloping your geometry, inverse  kinetics   and there are much more to explore as you become familiar with 3DS MAX.

There are various tools and technique available in 3DS MAX which provide you the above process. When you start using 3DS MAX you will explore more about  tools and technique

The software itself costs around $3800/yr. But not to worry!!! Where there is will there is a way!!! AUTODESK STUDENT provides free software  to students with 3 year license.

And Digital Tutors is one of the best place to learn make stunning movies, games…

Log on to http://www.digitaltutors.com/tutorial/1154-Introduction-to-3ds-Max-2014 for more info

So just go download your 3DS MAX, start watching the tutorials & let you imagination come out into your’s  laptop screens.

 

 

 

 

Extra Edgy Things For All Engineers

by pratikin Chemi, Comps, Electrical, For 1st yearites, For 2nd yearites, Internship, Mechanical, Tronics, UncategorizedLeave a Comment on Extra Edgy Things For All Engineers
Reading Time: 3 minutes
World Class Education Websites :- 

1.) edX.org

2.) coursera.org

3.) NPTEL.ac.in (watch at 1.5 x speed )

 

Internship and Workshop : Companies

 

1.) I3 Indiya

2.) Wegilant( Speacilized in Cyber Security)

3.) Robosapiens

4.) Technophilia

5.) Thinkware (Good for Matlab)

6.) Thinklabs

7.) Waayoo

8.) Learnics.in

9.) Logicbrigade.com

10.) STP.mbsgroup.in-(Also Has Course on F1 Car Design and Development)

 

To-Do Projects :-

 

Electronics Engineering

1.) SMPS

2.) POV

3.) LED CUBE

4.) FM Receiver

5.) Line Follower

6.) Temperature Controlled Fan

7.) Phone Jammer

8.) 555 Timer Projects

9.) Raspberry Pi

 

Mechanical Engineering

1.) Robotic Arm

2.) RC Plane

3.) Hovercraft

4.) Wall Climbing Robot

5.) Rope Climbing Robot

6.) Pole Climbing Robot

7.)Tricopter/Quadcopter

8.) Hydraulic Lift Arm

 

Chemical

1.) Batteries: Batteries of Your Own, like

  • Galvanic Cell
  • Zinc Air Battery
  • Al Air Battery
  • Al CU Battery

2.) Propulsion System: Car using

  • Vinegar+ Baking Soda
  • Decomposition of H2O2

3.) Search On MFC-Microbial Fuel Cell

4.) Research Alternate Source of Energy like Jatropha Seeds

 

 

 

 (continue on right column…..)

Electrical Engineering

1.) Power Generation from Moving Vehicles

2.) Power Theft Protection

3.) Booster Circuit

4.) Inverter Circuit

 

Civil Engineering

1.) Cardboard Model Building

2.) Designing On Softwares

3) Some Famous Civil Engineering Projects – Bridges, Tunnels and Dams

 

Computer Engineering

1.)Read: A Complete Reference to Java by Herbert Schildt

2.) Make Applets

3.) Android App Development

4.) Game Development

5.) AI-Artificial Intelligence: – Course on edX

6.) Read HTML: – HTML-5 for Web Development

7.) PHP

8.) Hacking

9.) Android- Learn to Root, Flash

10.) Google about Crack Paid Software using Decompiler and Disassembler!!!

11) Read  “C Programming Language” written by the creator of C – Dennis Ritchie

 

 

Extra-Edge Software

 

Civil

1.) Revit

2.) AutoCad

 

Computer Engineering

1.) Android App Development-IDE:-Eclipse

2.) Game Development Softwares

3.) Hacking-Backtrack OS

 

Chemical Engineering

1.) Aspen

2.) Super Pro Designer

3.) Open Foam

4.) Chemsketch

 

Mechanical Engineering

1.) Autodesk- AutoCad

2.)  Inventor

3.) Pro-e

4.) Google Sketch-Up

 

Electrical Engineering

1.) E-tap

2.) Matlab

3.) LabView

4.) PSCAD

5.) Simulink

6.) Lapack-Numerical Linear Algebra

 

Electronics

1.) MultiSim

2.) Proteus: Ckt and AVR MCU Simulation

3.) Eagle: PCB Designing

4.) Matlab: Mother of all things-

       Image Processing,Computer Vision,Control System Simulation, Digital Signal Processing

5.) NI’s LabView

 

Magazines

1.) ECE  – EFY

2.) Mech- Top Gear, Overdrive, AutoCar

3.) Chem- Chemical Engineering, World,Chemical Industry Digest

4.) Comps- Digit, Chip

5.) Electrical- Industrial Automation (IED Communications),IET(generation transmission and distribution)

 

Tech Fests

Even Semester

1.) IIT Bombay -Techfest Jan first week

2.) IIT Madras -Shaastra   Jan first week

3.) IIT Kharagpur -Kshitij Feb first week

4.) NIT Trichi-Pragyan-Feb End

5.) IIT Kanpur -TechKriti   March Mid

6.)BITS Pilani -Apogee   March Mid

7.) IIIT Hyderabad -Felicity

8.) IIT Roorkee -Cognizance

 

Odd Sem

1.) NIT Surathkal-Engineer – October End

2.) NIT Warangal-Technozion-   September End

 

God Father Sites

 

1.) http://www.howstuffworks.com/(Discovery’s Site-More of general Science)

2.) http://www.engineersgarage.com/

3.) http://www.extremeelectronics.com

4.) http://www.circuitstoday.com/

5.) www.societyofrobots.com (The best according to me)

6.) http://www.electronics-tutorials.ws/

7.) http://www.ece101.com/

8.) http://narobo.com/

9.) http://www.pyroelectro.com/

10.) http://students.iitk.ac.in/roboclub/tutorials.php

 

Electrical Engineering

1.) controleng.com

2.) control.com

3.) electric.net

4.) controlglobal.com

 

Mechanical Engineering

1.) pirate4x4.com

2.) carbibles.com

3.) SudhaCars.com

 

 (Continue on right column ……)

Computer Engineering

1.) code.org

2.) codechef.com

3.) spoj.com

4.) Java Applets-http://walter-fendt.de/ph14e/

 

Others

1.) internshala.com

2.) knowafest.com

3.) twenty19.com

 

 

Sites to buy robotics stuff

In India:

1.) http://nex-robotics.com/

2.) http://www.robokits.co.in/

3.) http://www.vegarobokit.com/

4.) http://www.rcbazaar.com/default.aspx

5.) http://www.rcdhamaka.com/

 

World best online robotics store:

1.) Jameco

2.) Solarbotics

3.) Digi-key

4.) Radioshack.com

 

Movies

1.) Gravity

2.) October Sky

3.) Iron Man-1, 2, 3

4.) Wall-E

5.) Batman

6.) G I Joe-1, 2

7.) Transformers-1, 2, 3

8.) The Social Network

9.) Avatar

10.) Real Steel

11.) Pirates of Silicon Valley

12.) Blade Runner

13.) 2002: A Space Odyssey

TELEVISION SHOWS

 

Discovery, Discovery Science, Discovery Turbo

1.) How Tech Works

2.) Dark matters

3.) Extreme Engineering

4.) Deconstructed

 

History TV

1.) Modern Marvels

 

NatGeo TV

1.) Big, Bigger, Biggest

2.) MegaStructures

3.) MegaFactories

4.) I Didn’t Know That

5.) Ultimate Factories

6.) Mega Factories

 

 

CEV - Handout