Immune system plays an essential role in the heart.

The embryonic macrophages in the heart promote healing after injury, A new research has revealed that immune system plays an essential role in the heart's response to injury. Now, researchers says that two major pools of immune cells are at work in the heart. Both belong to a class of cells known as macrophages. One appears to promote healing, while the other likely drives ignition which is detrimental to long-term heart function.

Macrophages have long been thought of as a single type of cell, the author said. Our study shows really many different types of macrophages that originate in different places in the body. Some are protecting and can help blood vessels grow and reborn tissue. Others are unhealthy and can bring to harm.

Actually, the heart is one of the few organs with a association of macrophages formed in the embryo and maintained into adults. The heart, brain and liver are the only organs that contain large numbers of macrophages that arise in the yolk sac, in very early stages of arises, and they think these macrophages tend to be protective. Healthy hearts maintain this population of embryonic macrophages, as well as a smaller pool of adult macrophages derived from the blood. But during cardiac stress such as high BP, not only were more adult macrophages recruited from the blood and brought to the heart, they actually replaced the embryonic macrophages.

The study is published in the journal Immunity. (ANI)

Industrial control system

Industrial control system(ICS) is a general term that encompasses several types of control systems, including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other smaller control system configurations such as skid-mounted Programmable Logic Controllers (PLC) often found in the industrial sectors and critical infrastructures. ICSs are typically used in industries such as Electrical, water, oil and gas, chemical, transportation, pharmaceutical, pulp and paper, food and beverage, and discrete manufacturing (e.g., automotive, aerospace, and durable goods.) These control systems are critical to the operation of the U.S. critical infrastructures that are often highly interconnected and mutually dependent systems. It is important to note that approximately 90 percent of the nation's critical infrastructures are privately owned and operated. Federal agencies also operate many of the industrial processes mentioned above; other examples include air traffic control and materials handling (e.g., Postal Service mail handling.) This section provides an overview of SCADA, DCS, and PLC systems, including typical architectures and components. Several diagrams are presented to depict the network connections and components typically found on each system to facilitate the understanding of these systems. The diagrams in this section do not address security and the diagrams in this section do not represent a secure architecture.

SOURCE:
NIST Guide to Supervisory and Data Acquisition-SCADA and Industrial Control Systems Security (2007)

DCSs

DCSs are used to control industrial processes such as electric power generation, oil and gas refineries, water and wastewater treatment, and chemical, food, and automotive production. DCSs are integrated as a control architecture containing a supervisory level of control overseeing multiple, integrated subsystems that are responsible for controlling the details of a localized process.  Product and process control are usually achieved by deploying feed back or feed forward control loops whereby key product and/or process conditions are automatically maintained around a desired set point. To accomplish the desired product and/or process tolerance around a specified set point, specific programmable controllers (PLC) are employed in the field and proportional, integral, and/or differential settings on the PLC are tuned to provide the desired tolerance as well as the rate of self-correction during process upsets. DCSs are used extensively in process-based industries. 

SCADA

SCADA (supervisory control and data acquisition)systems are highly distributed systems used to control geographically dispersed assets, often scattered over thousands of square kilometers, where centralized data acquisition and control are critical to system operation. They are used in distribution systems such as water distribution and wastewater collection systems, oil and gas pipelines, electrical power grids, and railway transportation systems. 

A SCADA control center performs centralized monitoring and control for field sites over long-distance communications networks, including monitoring alarms and processing status data. Based on information received from remote stations, automated or operator-driven supervisory commands can be pushed to remote station control devices, which are often referred to as field devices. Field devices control local operations such as opening and closing valves and breakers, collecting data from sensor systems, and 

monitoring the local environment for alarm conditions. 

SVURESET ELECTRICAL AND ELECTRONICS SYLLABUS

 

Unit I

Electric Circuits and Fields: Network graph, KCL, KVL, node and mesh analysis, transient response 

of dc and ac networks; sinusoidal steady-state analysis, resonance, basic filter concepts;  ideal current and voltage sources, Thevenin's, Norton's and Superposition and Maximum Power Transfer theorems, two -port networks, three phase circuits; Gauss Theorem, electric field and potential due to point, line, plane  and  spherical  charge  distributions;  Ampere's  and  Biot-Savart's  laws;  inductance;  dielectrics; capacitance.

Signals  and  Systems:  Representation  of  continuous  and  discrete-time  signals;  shifting  and  scaling 

operations;  linear,  time-invariant  and  causal  systems;  Fourier  series  representation  of  continuous 

periodic signals; sampling theorem; Fourier, Laplace and Z transforms.

Unit II

Electrical Machines:  Single phase transformer  -  equivalent circuit, phasor diagram, tests, regulation and  efficiency;  three  phase  transformers  -  connections,  parallel  operation;  auto -transformer;  energy conversion principles; DC machines - types, windings, generator characteristics, armature reaction and commutation, starting and speed control of motors; three phase induction motors  -  principles, types, performance  characteristics,  starting  and speed control;  single  phase  induction  motors; Synchronous machines -  performance, regulation and parallel operation of generators, motor starting, characteristics and applications; servo and stepper motors.

Unit III

Power Systems:  Basic power generation concepts; transmission line models and performance; cable performance, insulation; corona and radio interference; distribution systems; per-unit quantities; bus impedance  and  admittance  matrices;  load  flow;  voltage  control;  po wer  factor  correction; economic operation; symmetrical components; fault analysis; principles of over-current, differential and distance protection; solid state relays and digital protection; circuit breakers; system stability concepts,  swing curves and equal area criterion; HVDC transmission and FACTS concepts

Unit IV

Control Systems: Principles of feedback; transfer function; block diagrams; steady-state errors; Routh and Niquist techniques; Bode plots; root loci; lag, lead and lead-lag compensation; state space model; state Transition matrix, controllability and observability.

Electrical  and  Electronic  Measurements:  Bridges  and  potentiometers;  PMMC,  moving iron, dynamometer  and  induction  type  instruments;  measurement  of  voltage,  current,  power,  energy  and power factor; instrument transformers; digital voltmeters and multimeters; phase, time and frequency

measurement; Q-meters; oscilloscopes; potentiometric recorders; error analysis.

Unit V

Analog and Digital Electronics: Characteristics of diodes, BJT, FET; amplifiers - biasing, quivalent circuit  and  frequency  response; oscillators and feedback amplifiers; operational  amplifiers - Characteristics and applications; simple active filters; VCOs and timers; combinational and sequential logic circuits; multiplexer;  Schmitt  trigger;  multi-vibrators;  sample  and  hold  circuits;  A/D  and D/A converters; 8-bit microprocessor basics, architecture, programming and interfacing.

Power  Electronics  and  Drives:  Semiconductor  power  diodes,  transistors,  thyristors,  triacs,  GTOs, 

MOSFETs  and  IGBTs  - static  characteristics  and  principles  of  operation; triggering  circuits; phase 

control rectifiers; bridge converters - fully controlled and half controlled; principles of choppers and inverters; basis concepts of adjustable speed dc and ac drives 

Why industries are using Capacitor Banks

This phase difference can take two basics forms. 

• The current can “lag” the voltage when an inductive load (i.e., motors, magnetic HID ballasts) is used or
• The current can “lead” the voltage when a capacitive load(i.e., computers, electronic fluorescent ballasts) is used. 

When the current is out of phase with the voltage,the power utility has to supply more volt-amperes(VA) for a given wattage (W). Certain customers, such as industrial companies, may have to pay an additional charge if their power factor is too low which is why many industrial applications have banks of capacitors. These capacitors correct the poor power factor caused by the motors. This is also how manufacturers have been able to take a product that is inductive in nature, such as a magnetic HID ballast with a normal power factor, and include a “power factor correcting” capacitor to give the ballast a high power factor. 

REFERENCE:

LINK 1

What is power factor?

This is a very involved subject that will be dealt with in terms of field application and typical questions from end-users. Power factor is characteristic of alternating current (AC) circuits. Always a value between (0.0) and (1.0), the higher the number the greater/better the power factor. Circuits containing only heating elements (filament lamps, strip heaters, cooking stoves, etc.) have a power factor of 1.0. 

Other circuits containing inductive or capacitive elements (ballasts, motors, personal computer, etc.) usually have a power factor below 1.0. Normal power factor ballasts (NPF) typically have a value of (0.4) - (0.6). Ballasts with a power factor greater than (0.9) are considered high power factor ballasts (HPF). The significance of power factor lies in the fact that utility companies supply customers with volt-amperes, but bill them for watts. The relationship is (watts = volts x amperes x power factor). It is clear that power factors below 1.0 require a utility to generate more than the minimum volt-amperes necessary to supply the power (watts). This increases generation and transmission costs. Good power factor is considered to be greater than 0.85 or 85%.

Utilities may impose penalties on customers who do not have good power factors on their overall buildings.

Watts, or real power, is what a customer pays for. VARS is the extra“ power ” transmitted to compensate for a power factor less than 1.0. The combination of the two is called "apparent" power (VA or volt-amperes). Consider this popular analogy to clarify the relationship between real and apparent power.

We all know a glass of draft beer generally has a "head" on it. Let's say your favorite pub institutes a new policy -you only pay for the beer, not the foam. While the foam is just aerated beer, it is not really usable in that form. If the glass of beer is half foam, you pay half the price. This is the same principle as electricity generation - the consumer only pays for the beer (real power), not the foam (the "VARS" mentioned above).

Reference links:

REFER ONE