description about electromagnetic field strength exposure to how it's effect at human body and what is the standard value assign in the world according to generations, it's also related to manufacturer equipment, as well depend on area population , the exposure of electromagnetic propagation is probational to antenna height and input power of the antenna
Electric charges
Current
Potentialand its difference
Circuits
Heating effects
Magnetic effects
Magnetic Field Lines in straight and coiled conductors
Electromagnets
Electromagnetic Induction
Motors and Generators
Electric charges
Current
Potentialand its difference
Circuits
Heating effects
Magnetic effects
Magnetic Field Lines in straight and coiled conductors
Electromagnets
Electromagnetic Induction
Motors and Generators
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
2. Learning outcomes
• describe and explain the behaviour of permanent magnets,
including induced magnetism
• explain magnetisation and demagnetisation of ferromagnetic
materials in terms of magnetic domains
• describe how magnetic fields arise from moving charges, e.g.
in current-carrying straight wires, plane coils and solenoids
• describe how a transformer works, in terms of transformer
turns, currents & voltages
• describe the vectors involved in motor and dynamo effects
• explain why electricity is transmitted at high voltage
• experience relevant demonstration & class experiments
3. Overview
• contexts for teaching about electromagnetism
• permanent magnets
• electromagnets
• catapult effect and motors
• electromagnetic induction and generators
• Lenz’s law
• transformers & high voltage transmission of electricity
Circus of experiments
4. Misconceptions
• All metals are magnetic materials.
• Static charges interact with the poles of permanent magnets.
• Magnetic poles are located on the surface of a magnet.
[Careful observation shows that they are inside the magnet.]
5. Teaching challenges
Magnetic fields
• cannot be seen directly
• are three-dimensional, though commonly represented by 2-D
diagrams.
Some students find it hard to understand
• why permanent magnets can lose their strength
• that the geographic North pole must be a south magnetic pole
• that a current-carrying coil of wire induces (temporary)
magnetism in the iron core of an electromagnet.
• the operation of motors and generators (incl left hand rule)
6. A brief history
1600 William Gilbert, On magnetism; magnetic materials;
poles that attract & repel; Earth’s magnetic field, compass ‘dip’
1820 Hans Christian Oersted finds that an electric current deflects
a compass needle.
1820 Andre Marie Ampère finds that parallel wires
carrying current produce forces on each other.
1820s, 1830s Michael Faraday develops the concept of
electric field and shows that
electric current + magnetism -> motion (motor effect)
motion + magnetism -> electric current (electromagnetic induction)
1860s James Clerk Maxwell (1831-1879) establishes
a mathematical description of electromagnetism.
7. Motors everywhere
lifts & escalators; fans, turbines, drills; wheelchairs; car windscreen
wipers, starter motors, windows & side mirrors; motors in electric
cars, locomotives & conveyor belts; industrial robots, saws and
blades in cutting and slicing processes; food mixers & blenders,
microwave ovens; hand power tools such as drills, sanders,
routers; electric toothbrushes, shavers, hairdryers; vacuum
cleaners, sound systems, computers …
using electricity supplied by power station generators
8. Field lines indicate both direction and magnitude
(strength) of a magnetic field. They end at poles.
A compass needle can be thought of as a test dipole.
Magnetic flux density (‘field strength’) has symbol B, unit tesla.
Describing a magnetic field
Bar magnet
9. Common misconceptions
• All metals are magnetic materials.
• Static charges interact with the poles of permanent magnets.
• Magnetic poles are located on the surface of a magnet.
[Careful observation shows that they are inside the magnet.]
10. Magnetic poles: always pairs
A permanent magnet can be split into two or more
magnets, each with N and S poles which cannot be
isolated.
This suggests that the magnetic effect of a permanent
magnet comes from microscopic, circulating electric
currents.
11. Electron spin, inside atoms,
is the main cause of
ferromagnetism.
demagnetised
magnetised
Microscopic structure
Domain theory
12. Magnetising & demagnetising
Make a magnet
• by stroking
• by using DC coil carrying current
• by tapping while aligned with the Earth’s field
Demagnetise a magnet
• by dropping or banging randomly
• by heating
• by applying a diminishing AC current
13. Magnetic induction
A permanent magnet can induce temporary magnetism
in a ‘soft’ magnetic material.
• This causes attraction, but cannot cause repulsion.
• Use repulsion to test if an object is already magnetised.
14. Right hand screw rule, a.k.a. the ‘corkscrew’ or
‘pencil sharpener’ rule:
Place thumb in direction of current; fingers indicate direction of
the magnetic field.
Magnetic field of a straight wire
NB: Here
field lines
are closed
loops.
15. Magnetic field of a solenoid
Right hand grip rule: Wrap fingers around solenoid in
direction of current; thumb indicates N pole.
N S
17. A stronger electromagnet
Length of a solenoid is L
• Use iron or steel core (increasing permeability, )
• Increase the current, I
• Increase wraps or turns of solenoid, N.
I
L
N
B
18. Uses of electromagnetism
• loudspeaker
• moving coil microphone
• motors of various designs
• electric bell or buzzer (can be made in class, URLS below)
• moving coil galvanometer (ammeter)
• relay (control circuit with small current switches a second,
larger, current circuit)
Practical Physics website: model buzzer, model electric bell
23. The ampere defined
1 ampere: the steady current
which, when flowing in two
straight parallel wires of infinite
length and negligible cross-
section, separated by a distance
of one metre in free space,
produces a force between the
wires of
2 × 10-7 newtons per metre of
length
24. Electromagnetic induction
(‘Dynamo effect’)
Faraday’s law: Relative motion of a wire and a magnetic field will induce
an e.m.f. (voltage). If there is a complete circuit, a current will be induced
too.
– magnet stationary, coil moves
– coil stationary, magnet moves,
– coil stationary, magnetic field lines changing
Induced EMF is proportional to ‘the rate at which field lines are cut’.
Lenz’s Law: The induced current always flows in such a direction as to
oppose the change which causes it.
Faraday’s Electromagnetic Lab phet.colorado.edu/en/simulation/faraday
30. power in primary coil = power in secondary coil
Ideal transformer
IpVp = IsVs
Is
Ip
=
Vp
Vs
How a transformer works:
micro.magnet.fsu.edu/electromag/java/transformer/index.html
31.
32. High voltage transmission
Heating loss in a transmission cable:
Keep current small by making voltage large.
Grid voltages: 275 kV, 400 kV
Model power line
www.electrosound.co.uk
R
I
IR
I
IV
P 2
)
(
33. A sustainable energy future
‘… much more energy demand will be met through the electricity
system and generation will be added both centrally and
throughout the distribution system.’
‘Turning [carbon] emissions reduction targets into reality will require
more than political will: it will require nothing short of the biggest
peacetime programme of change ever seen in the UK.’
(Royal Academy of Engineering report, March 2010, Generating the future)
‘Renewable generation, which by its nature will be widely
distributed and mainly located in coastal and northern regions,
will also require considerable investment in electrical supply
system infrastructures both in terms of local distribution systems
and the national grid.’
(Royal Academy of Engineering, July 2006, Energy seminars report)
34. Safety
Hazard with strongest rare earth (neodymium)
magnets – swallow, shatter, pinch, interfere
• keep away from (>1m) any person who uses medical aids like a
pacemaker
• only responsible students or yourself to handle largest ones, or
more than one at a time
• wear safety spectacles and protective gloves when handling two
or more of the largest, most powerful magnets – risk of
shattering or pinching
• keep away from (>1m) electronic devices like computer
monitors, credit cards and memory sticks
35. Electromagnetism: a summary
• The force, F, acting on charge q
has two components:
E, electric field due to stationary charge(s).
B, magnetic field due to moving charge(s) - currents - with
relative velocity v.
• can be superposed e.g. E = E1 + E2 + …
• electric & magnetic fields store energy
• Maxwell’s equations: laws that describe the structure of the
electromagnetic field. E and B fields can exist without a circuit
and test magnetic dipole.
B
v
E
q
F
36. J. Clerk Maxwell (1865), ‘A Dynamical Theory of the Electromagnetic
Field’ Phil. Trans. R. Soc. Lond.
A changing electric field induces a changing magnetic field, and
vice versa. It therefore makes sense to talk of an
‘electromagnetic field’.
Electromagnetic waves propagate in
free space at c = 3 x 108 m/s.
E and B are always perpendicular to each other, and
perpendicular to the direction of propagation.
Electromagnetic waves
37. Em fields are real
‘The electromagnetic field is, for the
modern physicist, as real as the chair
on which he sits.’
Einstein and Infeld, 1938
38. Support, references
talkphysics.org
SPT 11-14 Electricity & magnetism
David Sang (ed., 2011) Teaching secondary physics ASE / Hodder
Practical Physics website: Electromagnetism topic
http://www.nuffieldfoundation.org/practical-physics/electromagnetism
PhET simulation Faraday’s Electromagnetic Lab