What is so special about SQUID (Superconducting Quantum Interference Device)?

SQUID was an accidental discovery in the Ford Motor Company’s research lab in Dearborn, Michigan. Five Researchers John Lambe, James Zimmerman, Arnold Silver, Robert Jaklevic, and James Mercereau made this vital discovery in superconductivity. They found, when cooling the SQUID a few degrees above absolute zero, it can detect a magnetic field that is less than 5 quintillionths of a tesla.

Superconductivity research was performed for gaining knowledge rather than for Ford’s commercial requirements. In 1963, the group discovered the Josephson Effect in a sample of super-cooled phosphorous-doped silicon. There are two main types of SQUIDS – Direct Current (DC) and Radio Frequency (RF).

SQUID is otherwise known as Superconducting Interferometers and they come in all sizes and shapes. With the growing technological advancement, these devices have considerably shrunk in size. Now there are nano squids which are compact unlike the earlier version which stretched across many kilometers. Nano Squid are a type of SQUID made out of carbon nanotubes which is just one nanometer in diameter. This SQUID is powerful enough to detect magnetic changes even in a molecule.  

Interferometers or SQUIDS work by splitting a wave into two components and sending them along different paths. These waves are recombined to find out if any of the waves has encountered any strange obstruction or interference. The phase of the two waves are checked. If both of them have travelled the same distance then the phase remains the same for both the waves. But if one of the waves encountered an obstruction then the phase changes.  The details about the obstruction can be found out by measuring the phase difference between the two waves.

Applications of SQUID:

Since the SQUID is able to detect such small levels of magnetic field it is used in a variety of ways such as:

• Making analog-to-digital convertors
• Traditional and quantum computing
• Detection of the cosmic microwave background
• Geophysical and archaeological surveys
• Imaging the brain, heart, and other body parts
• Non-destructive testing of materials and devices

These devices are effective in places where machinery cannot be taken apart to find out its wear and tear. In such instances, these SQUID devices help to detect the depreciation value of the working equipment. Moreover, the information gathered from these devices helps service engineers to take the corrective steps for ensuring the machines working condition, within the safety rules. 

In the medical field, these devices have proven to be helpful in an exemplary way for the physicians. The usage of SQUID in Magneto Encephalography field is a good example of that. An array of squids are used to study neural activity inside the brain. Likewise, Magnetogastrography measures functions of the stomach.  Drugs maybe orally applied and the instrument will trace the path of the drug to find out the function of the stomach. In such scenarios the Magnetic Marker Monitoring method is used.

SQUIDS are very commonly used in Magnetic Property Measuring Systems. The magnetic property of any material can be measured when the temperature range of 300 K - 400 K is maintained for these operations.

SQUID has innumerable uses and recent innovative research has proven these priceless devices to be a powerful help in various fields. SQUID falls under the electromagnetic interference topic which is a deeper look at the Electromagnetics section on the Electrical FE Exam.

Global Warming Challenges that Every Engineer Must be Aware of

 “Climate change is…a gross injustice—poor people in developing countries bear over 90% of the burden—through death, disease, destitution and financial loss—yet are least responsible for creating the problem.”

-          Barbara Stocking, CEO of Oxfam GB

The earth is constantly exposed to radiations from the sun and other planetary objects. Some of the sun radiations are reflected by the surface of the earth. The remaining radiation is absorbed by certain gases in the earth’s surface. These gases trap the heat of the radiations. Due to the trapping of this heat the earth warms up. This is known as Green House Effect.

The gases which trap the heat are known as greenhouse gases. A few examples of greenhouse gases are ozone, carbon dioxide, nitrous oxide, methane, and water vapour. The term greenhouse effect comes from the concept of a garden inside a glass room. The glass absorbs all the heat. The glass does not allow heat to escape from the garden and eventually heats up the garden. So, the term greenhouse effect became applicable not only to gardens but also to the earth.. A similar example is how heat enters a car through the glass windows. If the car windows are closed the heat cannot escape and the car warms up.

The greenhouse effect is essential to maintain adequate warmth of the globe as well. If the greenhouse gases volume increases too much then it leads to an increase in global warming. There are lot of human activities that generate gases that trap sunlight. Some common activities are:

·          Cutting trees and burning them

·          Burning of oil, coal, and natural gas – fossil fuels

·          Burning of solid waste

·          Decomposition of organic waste

·          Industrial output and agricultural processes

Of all the most common gases, carbon-dioxide, due to its large quantities, causes most of global warming. If human beings control the activities that lead to greenhouse gas generation, then global warming will also be controlled. While preparing for the Professional Engineer Exam, the engineer will be able to understand global warming challenges.

Consequences of Global Warming

Impact on Weather: Some regions of the earth will become warmer, while other regions become colder. The weather changes will have an impact on the types of crops that can be grown in certain regions. Animals, plants, and human beings will be affected by these significant weather changes.

Impact on Sea Level: As ice melts due to global warming, the sea level also increases. This increase in sea level by 20-40 cm will lead to floods that can destroy livelihood and farmlands.

Impact on Farming: Every crop needs a optimal temperature to provide a good yield. But due to global warming the temperature fluctuates and so crops will not have the desired temperature and yield less. Less crop yield may lead to hunger in certain parts of the globe.

Make Profits with Engineering Economics

Engineers design the world. When they design or create the world they have to take into account the economic feasibility and profits of the project. It is not sufficient if an engineer is just creative. He or she must know how to make money or profits with that creativity. Engineers have to make a lot of decisions and each decision is arrived after considering a lot of alternatives. Engineering economics is about listing, estimating, and evaluating the monetary performance of each alternative.

While accounting is used to evaluate past performance, engineering economics is used to predict and analyse future events. The time taken for a project to yield results and the related ambiguity are the two important factors considered in engineering economics.  It is easy to predict the engineering economics for a small project. But for a large project the cost, time, and ambiguity will be greater than that of a small project.

For example, let us look at what factors affect engineering economics for the manufacturing industry. If the services are improved the increased cost has to be taken into account. Buying new equipment or replacing existing equipment; creating a new product or bringing variations to an existing product and general cost reduction leads to economic discussions.

In any engineering economy study, a set of steps as shown below are followed:

1. Problem description
2. Alternative solutions to reach goal
3. Cash flow and other estimates
4. Measure of worth criterion
5. Engineering Economic analysis
6. Best alternative selection
7. Implementing and monitoring

In addition to following the prescribed steps, getting money or return in the near future must be considered more appealing than getting money in the distant future. When there are a set of alternatives the differences in the alternatives have to be evaluated. Marginal revenue must be higher than marginal cost. It is not advisable to take extra risk if there is no extra return for the project or activity. Taking extra risk may decrease the value of the invested money over time.

The Time Value of Money (TVM) is a very important concept.  TVM is the concept of the value of any money increasing over a period of time. People may invest the money to earn greater returns or the money in the bank may earn some interest. So, it is accepted that the value of money keeps increasing if properly utilized.

The parameters considered for engineering economics are:

• Fixed Cost
• Sunk Cost
• Variable Cost
• Opportunity Cost
• Marginal Cost
• Marginal Revenue
• Profit-Volume Ratio
• Technical Efficiency
• Economic Efficiency
• Simple Interest
• Compound Interest
• Cash Flow diagram
• Depreciation/Inflation
• Benefit-Cost ratio
• Economic Order of Quantity (EOQ)
• Minimum attracting rate of return

An engineer must be cost conscious and use the engineering economic formulas and tools to test the monetary success of the project. Engineering Economics is an important subject covered on the PE Exam.