The Magnetic Field Distribution In Alternative Current.

The Magnetic Field Distribution In Alternative Current. 

When the conductor is carrying Alternating Current, the internal magnetic field strength rises from zero at the centre to a maximum at the surface. However, the field is concentrated in a thin layer near the surface of  the conductor. This is known as the "skin effect."  The skin effect is evident in the field strength versus distance graph for a magnetic conductor shown to the right. The external field decreases with increasing distance from the surface as it does with DC. It should be remembered that with AC the fields constantly varying in strength and direction.
In a hollow circular conductor there is no magnetic field in the void area. The magnetic field is zero at the inside wall surface and rises until it reaches a maximum at the outside wall surface. As with a solid conductor, when the conductor is a magnetic material, the field strength within the conductor is much greater than it was in the nonmagnetic conductor due to the permeability of the magnetic material. The external field strength decreases with distance from the surface of the conductor. The external field is exactly the same for the two materials provided the current level and conductor radius are the same.

Advantages and limitation of ultrasonic testing.

 ADVANTAGES OF ULTRASONIC INSPECTION: - 

 1)   It is sensitive to both surface and subsurface discontinuities.

       
 2)   The depth of penetration for flaw detection or measurement is superior to the NDT methods.

 3)   Only single sided access is needed when the pulse echo technique is used.

 4)   It is highly accurate in determining reflector position and estimating size and shape.

                                  

 5)   Minimal part preparation is required.

                                                                                

 6)   Electronic equipment provides instantaneous results.

 7)   Detailed images can be produced with automated systems.

 8)   It has other uses,such as thickness measurement,in addition to flaw detection.                                        

LIMITATION:-

 1)  Surface must be accessible to transmit ultrasound.

 2)  skill and training is more extensive than with some other methods.

 3) It normally requires a coupling medium to promote the transfer of sound energy into the test specimen.

 4)  Materials that are rough, irregular in shape,very small,exceptionally thin or not homogenous are difficult.

 

 5)   Cast iron and other coarse gained materials are difficult to inspect due to low sound transmission and high signal noise.                                                                                                                        

 6)  Linear defects oriented parallel to the sound beam may go undetected.

 7)  Reference standards are required for both equipment calibration and characterization of flaws.                                                                                                                                  

Disadvantages of computer.

Disadvantages of computers:

1)  Health issues: Excessive computer use can lead to health problems such as eye strain, back and neck pain, and musculoskeletal disorders. Prolonged sitting and sedentary behavior can also contribute to obesity and other lifestyle diseases.

2)  Security risks: Computers are susceptible to security threats such as viruses, malware, and hacking. Users must take precautions, such as using antivirus software and strong passwords, to protect their personal information and data.

3)  Dependency: As people become reliant on computers for various tasks, there is a risk of dependency and loss of manual skills. Additionally, technical issues or power outages can disrupt productivity and cause frustration.

4)  Social isolation: Spending excessive time on computers can lead to social isolation and a lack of face-to-face interaction. Virtual communication may not provide the same level of human connection as in-person interactions.

6)  Privacy concerns: Computers store vast amounts of personal data, raising concerns about privacy and data breaches. Users must be cautious about sharing personal information online and take steps to protect their privacy.

7)  Environmental impact: The production and disposal of computers contribute to environmental issues such as increased electronic waste and energy consumption. Responsible disposal and recycling of electronic devices are important to minimize the negative impact on the environment.

Computers have undoubtedly revolutionized various aspects of our lives, but it is important to use them responsibly and be aware of the potential drawbacks. Striking a balance between computer usage and other activities is essential for overall well-being.

Advantages of computer.

Advantages of computer.

1)  Efficiency: Computers can process large amounts of data quickly and accurately, increasing productivity and efficiency in various tasks, including data analysis, calculations, and communication.

2)  Storage: Computers have the ability to store vast amounts of data, eliminating the need for physical paper files and allowing for easy organization and retrieval of information.

3)  Communication: Computers enable instant communication through email, messaging apps, video conferencing, and social media platforms, connecting people globally and facilitating collaboration and information sharing.

4)  Automation: Computers can automate repetitive tasks, reducing human error and freeing up time for more complex and creative work.

5)  Access to information: The internet provides access to a wealth of information and resources, allowing users to search for information, learn new skills, and stay informed about current events.

6)  Entertainment: Computers offer various forms of entertainment, including online gaming, streaming movies and TV shows, and music production. They provide a platform for creativity and relaxation.