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Collaborative Research in Programmable Matter
May 18, 2018

This project combines modular robotics, systems nanotechnology and computer science to create the dynamic, 3-Dimensional display of electronic information known as claytronics.

Our goal is to give tangible, interactive forms to information so that a user’s senses will experience digital environments as though they are indistinguishable from reality.

Claytronics is taking place across a rapidly advancing frontier.  This technology will help to drive breathtaking advances in the design and engineering of computing and hardware systems.

Our research team focuses on two main projects:

♦ Creating the basic modular building block of claytronics known as the claytronic atom or catom, and

♦ Designing and writing robust and reliable software programs that will manage the shaping of ensembles of millions of catoms into dynamic, 3-Dimensional forms.

Realizing the vision of claytronics through the self-assembly of millions of catoms into synthetic reality will have a profound effect on the experience of users of electronic information. This promise of claytronic technology has become possible because of the ever increasing speeds of computer processing predicted in Moore’s Law.

This website will introduce you to the ideas that are driving claytronics, the research team that is working to make it happen, and the hardware and software projects that enable the building of claytronic ensembles.

Development of this powerful form of information display represents a partnership between the School of Computer Sciences of Carnegie Mellon University, Intel Corporation at its Pittsburgh Laboratory and FEMTO-ST Institute.  As an integral part of our philosophy, the Claytronics Project seeks the contributions of scholars and researchers worldwide who are dedicating their efforts to the diverse scientific and engineering studies related to this rich field of nanotechnology and computer science.

To understand the future of claytronics, watch the concept video [.mov] created by Carnegie Mellon’s Entertainment Technology Center.

Use the links to the left to see a list of publications, some videos and photos documenting our progress, a partial list of talks we have given, and people working on the project.

The program of the programmable matter is

  author = {Pillai, Padmanabhan and Campbell, Jason D. and Kedia,
     Gautam and Moudgal, Shishir and Sheth, Kaushik},
  title = {A 3D Fax Machine based on Claytronics},
  booktitle = {IEEE/RSJ International Conference on Intelligent Robots
     and Systems {(IROS '06)}},
  venue = {IEEE/RSJ International Conference on Intelligent Robots and
     Systems (IROS)},
  month = {October},
  year = {2006},
  keywords = {Applications of Claytronics},
  url = {http://www.cs.cmu.edu/~claytronics/papers/pillai-iros06.pdf},
  abstract = {This paper presents a novel application of modular
     robotic technology. Many researchers expect manufacturing
     technology will allow robot modules to be built at smaller and
     smaller scales, but movement and actuation are increasingly
     difficult as dimensions shrink. We describe an application --- a
     3D fax machine --- which exploits inter-module communication and
     computation without requiring self-reconfiguration. As a result,
     this application may be feasible sooner than applications which
     depend upon modules being able to move themselves. In our new
     approach to 3D faxing, a large number of sub-millimeter robot
     modules form an intelligent ``clay'' which can be reshaped via
     the external application of mechanical forces. This clay can act
     as a novel input device, using intermodule localization
     techniques to acquire the shape of a 3D object by casting. We
     describe software for such digital clay. We also describe how,
     when equipped with simple inter-module latches, such clay can be
     used as a 3D output device. Finally, we evaluate results from
     simulations which test how well our approach can replicate
     particular objects.},

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Uninterruptible power supplies (UPS) are used to provide power when regular utility power is unavailable.  Although they are commonly used for providing power in remote locations or emergencies, this is not because they are the same as auxiliary power units, emergency power units or standby generators.

Unlike the aforementioned power sources, UPS provides an immediate and continuous supply of power to a device, hence protecting it from power interruption and allowing time for auxiliary or emergency powers, to kick in equipment to be safely shut down or utility power restored.


The major aim of this was to design a system which will be able to convert battery voltage(12v) to 220v, which is equivalent to wall outlet and secondly able to charge the battery.

The chapter one of this work, gives the over-view of UPS, it’s importance, uses, and application and some of its special features like its ability to correct frequency instability and many more.

Secondly, this work dealt with all components used in the construction of the device, there working condition and uses. Some basic abstract phenomenon were also treated like wave forms and electronic switching.

The chapter three, basically dealt on all electrical measuring instrument used in and on the device, how they are used, why and where.

The fourth chapter explains how the components where assembled into section and the sectional connection used to form the device.

The last chapter is a simple conclusion with honest recommendation.













CERTIFICATION         –        –        –        –        –        –        –        –        i

DEDICATION     –        –        –        –        –        –        –        –        ii

ACKNOWLEDGEMENT       –        –        –        –        –        –        iii

ABSTRACT        –        –        –        –        –        –        –        –        iv

TABLE OF CONTENT          –        –        –        –        –        –        –        v


1.1     INTRODUCTION         –        –        –        –        –        –        1

1.1     AIMS AND OBJECTIVES     –        –        –        –        –        8

1.2     SCOPE OF THIS PROJECT   –        –        –        –        –        8

1.3     AVAILABILITY OF DESIGN MATERIALS      –        –        8



2.1     LITERATURE REVIEW        –        –        –        –        –        9

2.1     WHAT IS A UPS?         –        –        –        –        –        –        –        9

2.2     WAVEFORMS    –        –        –        –        –        –        –        9

2.2.1 SQUAREWAVE  –        –        –        –        –        –        –        9

2.2.2 MODIFIED SINE WAVE        –        –        –        –        –        10

2.2.4 TRUE SNE WAVE        –        –        –        –        –        –        –        10

2.3     RESISTORS        –        –        –        –        –        –        –        11

2.4     CAPACITORS     –        –        –        –        –        –        –        12

1.4.1 CAPACITANCE  –        –        –        –        –        –        –        13

2.4.2 ELECTROLYTIC CAPACITOR       –        –        –        –        14


CAPACTOR –      –        –        –        –        –        –        –        14

2.5     DIODE       –        –        –        –        –        –        –        –        16

2.5.1 MOUNTING A DIODE –        –        –        –        –        –        18

2.5.2 CHARACTERISTICS CURVES OF A DIODE   –        –        18

2.5.3 IDEAL DIODE     –        –        –        –        –        –        –        19

2.5.4 LIGHT EMITTING DIODE     –        –        –        –        –        19

2.5.5 DIODES AS RECTIFIERS      –        –        –        –        –        21 HALF-WAVE RECTIFIER  –        –        –        –        –        22  FULL-WAVE, CENTER-TAP RECTIFIE       –        –        23

2.5.6    FILTERS  –        –        –        –        –        –        –        –        24

2.6     TRANSISTORS   –        –        –        –        –        –        –        26

2.6.1 TRANSISTOR AS A SWIRCH        –        –        –        –        –        26

2.6.2 MOSFETS  –        –        –        –        –        –        –        –        28 SUPER-HIGH INPUT IMPEDANCE –    –        –        –        29 SETBACKS IN MOSFETS –        –        –        –        –        29 ITS FLEXIBILITY      –        –        –        –        –        –        30

2.7      OPTO-COUPLER        –                  –        –        –        –        –        30

2.7.1  OPTO-COUPLER CHARACTERISTICS –         –        –        –        31

2.7.2  ITS INPUT –        –        –        –        –        –        –        –        32

2.7.3 ITS OUTPUT       –        –        –        –        –        –        –        32

2.7.4  ITS OPERATING MODE      –        –        –        –        –        33

2.8     THE SG3524 INTEGRATED CIRCUIT   –        –        –        33

2.8.1  OPERATING PRINCIPLE OF SG3524    –        –        –        34


3.0     METHODOLOGY        –        –        –        –        –        –        36

3.1     ELECTRONIC WORKBENCH        –        –        –        –        37

3.2     GALVANOMETER      –        –        –        –        –        –        37

3.3     OSCILLOSCOPE –        –        –        –        –        –        –        38

3.4     VOLTMETER     –        –        –        –        –        –        –        39

3.5     AMPMETER       –        –        –        –        –        –        –        41

3.6     WATTMETER    –        –        –        –        –        –        –        43

3.7     MULTIMETERS –        –        –        –        –        –        –        44



4.0     DESIGN AND CONSTRUCTION METHODS  –        –        46

4.1     COMPLETE CIRCUIT DIAGRAM OF A UPS   –        –        47

4.2     STAGE BY STAGE DESIGN          –        –        –        –        –        47

4.2.1  OSCILLATOR SECTION      –        –        –        –        –        50

4.2.2  DRIVER/SWITCHING SECTION   –        –        –        –        51

4.2.3  THE OUTPUT SECTION      –        –        –        –        –        52

4.2.4  THE CHANGEOVER SECTION    –        –        –        –        53

4.2.5  THE LOW BATTERY CUT-OFF SECTION      –        –        54

4.3     COMPONENT JUSTIFICATION    –        –        –        –        55

4.3.1  MOSFETS –        –        –        –        –        –        –        –        55

4.3.2 SG3524 OSCILLATOR –        –        –        –        –        –        55

4.3.3 OPTO-COUPLER –        –        –        –        –        –        –        56

4.3.4 RESISTORS         –        –        –        –        –        –        –        –        56

4.4 TEST AND ANALYSIS   –        –        –        –        –        –        56

4.4.1  TESTING AND SETTING THE INVERTER    –        –        57

4.5     BILL OF ENGINEERING CONSTRUCTION    –        –        60



5.0 CONCLUSION        –        –        –        –        –        –        –        62

5.1 RECOMMENDATION     –        –        –        –        –        –        62

REFERENCES   –        –        –        –        –        –        –        63











Fig 1.                   Offline/ standby diagram      –        –        –        5

Fig 2.                   A capacitor         –        –        –        –        –        12

Fig 3.                   Capacitors –        –        –        –        –        –        15

Fig 4.                   Circuit Symbol of a diode –   –        –        –        17

Fig 5.                   A Led         –        –        –        –        –        –        20

Fig 6.                   Half-wave rectifier       –        –        –        –        21

Fig 7.                   Half wave Rectifier      –        –        –        –        22

Fig 8.                   A full-wave centre tap rectifier       –        –        24

Fig 9.                   A Simple filter     –        –        –        –        –        25

Fig 10.       Transistor as a Switch –        –        –        –        27

Fig 11.       A Transistor as a Switch      –        –        –        27

Fig 12.       A Mosfet    –        –        –        –        –        –        28

Fig 13        Opto-Coupler’s Input   –        –        –        –        32

Fig 14.       Inputs and output circuit of an opto-coupler – 32

Fig 15.       A Digram of a Voltmeter       –        –        –        41

Fig 16.       Diagram of Amp meter         –        –        –        –        42

Fig 17        Diagram of a Wattmeter arrangement   –        43

Fig 18        Oscillator Circuit           –        –        –        –        –        49

Fig 19        Pre-Driver Section       –        –        –        –        51

Fig 20        Change over circuit of the UPS    –        –        53

Fig 21        Low battery cut-off circuit     –        –        –        54CHARACTERISTICS CURVES OF A DIODE   CITORS

l and may God reward you. , Sir CHristopher chukwu and family, Elder Emmanuel a




As blackouts roll through power-starved communities, the threat to you and your computer is not the lack of electricity, but the change in power. When the lights are off and you are about to start any industrial or computer-based projects,  all your efforts will be wasted. Even when your system acts as a server, a sudden shutdown could disrupt the processing of many others. You can make your work immune to the intransigence of rolling blackouts and protect against many other types of unexpected power disturbances. Your secret weapon is the uninterruptible power supply or uninterruptible power source. Commonly called the UPS, this devices is a cleaver threefold package-a set of battery, an inverter that transforms the low-voltage direct current of the batteries into the standard alternating current equivalent to your wall outlet, and a battery changer that assures that reserve power storage system (the batteries) with interfaces to mach it to utility power and your computer system. A UPS differs from an auxiliary emergency power system or standby generator in that it will provide instantaneous or near-instantaneous protection from input power interruptions by means of one or more attached batteries and associated electronic circuitry for low power users, and or by means of diesel generators and flywheels for high power users. While not limited to protecting any particular type of equipment, a UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption and/or data loss. UPS units range in size from units designed to protect a single computer without a video monitor (around 200 VA rating) to large units powering entire data centers, buildings, or even cities. The UPS is designed to project against changes, specifically a temporary loss of electrical supply.

This project focuses on conversion of AC to DC and from DC to AC power inverters, which aim to efficiently transform a DC power source to a high voltage AC source, similar to power that would be available at an electrical wall outlet. Inverters are used for many applications, as in situations where low voltage DC sources such as batteries, solar panels or fuel cell must be converting electrical power from a car battery to run a laptop, TV or cell phone.




DC and AC Current

In the world today there are currently two forms of electrical transmission, Direct Current (DC) and Alternating Current (AC), each with its own advantages and disadvantages. DC power is simply the application of a steady constant voltage across a circuit resulting in a constant current. A battery is the most common source of DC transmission as current flows from one end of a circuit to the other. Most digital circuitry today is run off of DC power as it carries the ability to provide either a constant high or constant low voltage, enabling digital logic to process code executions. Historically, electricity was first commecially transmitted by Thomas Edison, and was a DC power line. However, this electricity was low voltage, due to the inability to step up DC voltage at the time, and thus it was not capable of transmitting power over long distances.


P=IV = I2R


As can be seen in the equations above, power loss can be derived from the electrical current squared and the resistance of a transmission line. When the voltage is increased, the current decreases and concurrently the power loss decreases exponentially; therefore high voltage transmission reduces power loss. For this reasoning electricity was generated at power stations and delivered to homes and businesses through AC power. Alternating current, unlike DC, oscillates between two voltage values at a specified frequency, and it’s ever changing current and voltage makes it easy to step up or down the voltage. For high voltage and long distance transmission situations, all that is needed to step up or down the voltage of the transformer. Developed in 1886 by William Stanley Jr., the transformer made long distance electrical transmission using AC power possible.

Electrical transmission has therefore been mainly based upon AC power, supplying most Nigerian homes with a 220 volt AC source. It should be noted that since 1954 there have been many high voltage DC transmission systems implemented around the globe with the advent of DC/DC converters, allowing the easy stepping up and down of DC voltages. Like DC power, there exist many devices such as power tools, radios and TV’s that run off of AC power.

It is therefore crucial that both forms of electricity transmission exist; the world cannot be powered with one simple form. It then becomes a vital matter for there to exist easy ways to transform DC to AC power and vice versa in an efficient manner. Without this ability people will be restricted to what electronic devices they use depending on the electricity source available. Electrical AC/DC converters and DC/AC inverters allow people this freedom in transferring electrical power between the two.

Offline / standby


Inverters and Applications

Power inverters are devices which can convert electrical energy of DC form into that of AC. They come in all shapes and sizes, from low power functions such as powering a car radio to that of backing up a building in case of power outage. Inverters can come in many different varieties, differing in price, power, efficiency and purpose. The purpose of a DC/AC power inverter is typically to take DC power

supplied by a battery, such as a 12 volt car battery, and transform it into a 220 volt AC power source operating at 50Hz, emulating the power available at an ordinary household electrical outlet. Power inverters are used today for many tasks like powering appliances in a car such as cell phones, radios and televisions. They also come in handy for consumers who own camping vehicles, boats and at construction sites where an electric grid may not be as accessible to hook into. Inverters allow the user to provide AC power in areas where only batteries can be made available, allowing portability and freeing the user of long power cords. However, most UPS units are also capable in varying degrees of correcting common utility power problems like:

  1. Power failure: defined as a total loss of input voltage.
  2. Surge: defined as a momentary or sustained increase in the mains voltage.
  3. Sag: defined as a momentary or sustained reduction in input voltage.
  4. Spikes, defined as a brief high voltage excursion.
  5. Noise, defined as a high frequency transient or oscillation, usually injected into the line by nearby equipment.
  6. Frequency instability: defined as temporary changes in the mains frequency.
  7. Harmonic sinusoidal waveform distortion: defined as a departure from the ideal expected on the line

Factors to consider when designing an inverter is

  • The input voltage
  • The output voltage
  • The frequency of the oscillators
  • The rating of the load to be powered by the inverter
  • The ampere range of the charging unit
  • The cost of the construction
  • The relative importance of the inverter
  • The ampere ranger of the charging unit
  • The cost of the construction
  • The relative importance of the inverter at that time specification
  • C input voltage (12V-24V)
  • C output voltage (220v-240v)
  • Output frequency (50Hz-60Hz)
  • Output power (450-550)
  • Maximum power (550)
  • Continuous output power (500)
  • Overload shutdown
  • Low voltage shutdown




The objective of this project may be summarized as listed below


  • To give a brief introduction on what UPS.
  • To highlight the basic components used in the construction of a UPS and their functions .
  • To describe the way in which there are designed and
  • Finally to highlight its application and relevance in the society





This project research encompasses the features of the variety of the components used in the construction of a UPS, their limitations and favourable working conditions, and the application of inverter in different field.




Materials used in the construction of this UPS are readily available in electronic stores across the country and are also very affordable depending on the rating of the UPS to be constructed.


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Fan is an unavoidable electrical appliance in our day to day life. While basic fan has evolved very little, the methods of controlling its speed have change vastly, from bulky regulators using resistances, to the present day miniature solid state regulators.

In our paper, we have devised a method to control the fan using a remote. Though they have Leen ways to control speed using remote, the novelty of our method lies in the fact that any kind of remote can be used to control its speed.

For example, consider a TV remote. Just like the fan, a TV is also considered a basic necessity nowadays. And if there is a TV, there is a remote.

These remote can be used to control the fan speed. Thus it is a universal method. This innovation is highly recommendable for elder people, who have problems like arthritis, and cannot walk to the switch board to change the speed. It is also a great benefit to sick people.

Remote control facilities the operation of fan regulators around the home or office from a distance. It provides a system that is simple to understand and also to operate, a system that would be cheap and affordable, a reliable and easy to maintain system of remote control and durable system irrespective of usage. It adds more comfort to everyday living by removing the inconvenience of having to move around to operate a fan regulator. The system seeks to develop a system that is cost effective while not under mining the need for efficiency. The first remote control, called boneset was developed in 1950 by Zenith Electronics Corporation (then known as Zenith Radio Corporation). He devices  was developed quickly, and it was called “Zenith Space Command”, the remote went into production in the fall of 1956, becoming the first practical wireless remote control device.

Today, remote control is a standard on other consumer electronic products, including VCR cable and satellites boxes, digital video disc players and home audio players. And the most sophisticated TV sets have remote with as many as 50buttons. In year 2000, more than 99 percent of all TV set and 100 percent of all VCR and DVD players sold are equipped with remote controls. The average individual these days probably picks up a remote control at least once or twice a day.

Basically, a remote control works in the following manner. A button is pressed. This completes a specific connection which produces a Morse code line signal specific to that button. The transistor amplifies the signal and sends it to the LED which translates the signal into infrared light. The sensor on the appliance detect the infrared light and reacts appropriately. The remote control’s function is to wait for the user to press a key and then translate that into infrared light signals that are received by the receiving appliance. The carrier frequency of such infrared signals is typically around 36kHz. Usually, the transmitter part is constructed so that the transmitter oscillator which drives the infrared transmitter LED can be turned on/off by applying a TTL (transistor-transistor logic) voltage on the modulation controlled input. On the receiver side, a photo transistor or photodiode takes up the signals.


The objective of putting up this project, therefore, is to design equipment that can facilitate a convenient and easy way of controlling our electric fan, especially in powering them, without always going to appliances physically by ourselves.

This objective will be accomplished using various components which include a microcontroller (AT89C51) and NE555 IC which acts as the backbone of the project together with other components.

There is a trigger signal from the preceding blocks. While, for the first multi vibrator, trigger is sent from the IR receiver, for the second multivibrator, trigger is sent from the Opto-coupler.


















During British rule, the word came to be used in a special sense by Anglo-Indians to mean a large swinging fan, fixed to the ceiling, and pulled by a servant, called Punkawallah.

In the 17th century, the experiments of scientists like Otto Von Guericke, Robert Hooke and Robert Boyle, elucidated the principles of vacuum and airflow. The English architect Sir Christopher Wren applied an early ventilation system in the Houses of Parliament that used bellows to circulate the air. The Houses of Parliament would be the catalyst for much later improvement and innovation. John Theophilus Desaguliers, a British engineer, demonstrated a successful use of a fan system to draw out stagnant air from the coal mines in 1727 and soon afterwards he installed a similar apparatus in Parliament.

In 1849, a 6m radius steam driven fan, designed by William Brunton, was made operational in the Gelly Gaer Colliery of South Wales. The model was exhibited at the Great Exhibition of 1851. Improvements in the technology were made by Jame Nasmyth, Frenchman Theophile Guibal and J.R. Waddle. Between the years 1882 and 1886, New Orleans resisdent Schuyler Skaats Wheeler invented a fan powered by electricity. It was commercially marketed by the American firm Crocker and Curtis Electric Motor Company. In 1882, Philip Diehl introduced the electric ceiling fan. Heat-convection fans fueled by alcohol, oil or kerosene were common around the turn of the 20th century.

In the 1920s, industrial advances allowed steel fans to be mass produced in different shapes, bringing fan prices down and allowing more homeowners to afford them. In the 1930s, the first art deco fan (the “swan fan”) was designed.

In the 1950s, fans were manufactured in colours that were bright and eye catching. Central air conditioning in the 1960s caused many companies to discontinue production of fans. In the 1970s, Victorian-style ceiling fans became popular.

In 1998, Walter K. Boyd invented the HVLS ceiling fan, Boyd developed a slow moving fan with a very large 8-feet diameter. Due to its size, the fan moved a large column of air down and out 360 degrees and continuously mixed fresh air with the stale air inside the barn. They are used in many industrial settings, because of their energy efficiency.

By the early 2000s, the number of consumer electronic devices in most homes greatly increased. According to the Consumer Electronics Association, an average American home has four remotes. To operate a home theater as many as five or six remotes may be required, including one for cable or satellites receiver, VRC or Digital Video Recorder, DVD player, TV and audio amplifier. Several of these remotes may need to be used sequentially, but, as there are no accepted interface guidelines, the process is increasingly cumbersome. Many specialists, including Jakob Nielsen, a renowned usability specialist and Robert Alder, the inventor of the modern remote, note how confusing, unwieldy and frustrating the multiplying remotes have become.

Most modern remote control alert systems for appliances use infrared diode to emit a beam of light that reaches the device or equipment.

Therefore the concept of remote control is further expanded in another form by applying it in a circuit that is used to power many appliances automatically by pressing buttons on the remote control.
















            It consists of a CD4017 decade counter IC. It has one input pin, ten outputs pins from Q0 to Q9 and one reset pin. Here, we are using the outputs Q0 – Q4, and shorting Q6 and reset pins. The outputs Q0-Q4 are routed to the threshold-discharge pins of the second multivibrator via a resistor and capacitor network. The resistances R5-R9 and the capacitance C5 fix the output pulse width of the multivibrator .


The main purpose of an Opto-isolator is to prevent the high voltages or rapidly changing voltages on one side of the circuit from damaging components or distorting transmissions on the other side. In our project we use a MOC3021 Opto-isolator IC to control the 230V AC voltage on the load using a low voltage signal from the second multivibrator. However, the two stages have a complete electrical isolation.




It is essentially an Opto-isolator, but functioning as zero detector. It sends out pulses when it detects a zero crossing on the stepped down input 12V AC line. These pulses are used to trigger the second multivibrator. We use the Opto-coupler IC MC2TE.


We need a low voltage for power supply to entire low voltage control circuit. We step down the 230V AC to 12V-0-12V using a centre tapped transformer. This voltage is rectified to DC and using a LM7809 IC, converted to 9V DC which is used to power the control circuitry.

            SRC MODULE

            We are using a BT136 triac to control the fan speed, using the MOC3021 Opto-isolator to trigger it. Since we do not have any beforehand experience of working with 230V AC, the application circuit is as directed by manufacturers on their datasheet with little modification.


The components used in construction of the remote control fan regulator are listed explained below.

2.2       RESISTOR

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. The current through a resistor is in direct proportion to the voltage across the resistor’s terminals. This relationship is represented by Ohm’s law: R=V/I. The function of a resistor is to resist the flow of electric current in an electronic circuit. Resistors are classified into two classes of resistors; fixed resistors and the variable resistors. A resistor is made of either carbon film or metal film. Its SI unit is (ohms) Ω







         Fig 2.1 A Resistor




                  Fig 2.2 Electronic Symbol of Resistor


A light-emitting diode (LED) is a semi-conductor light source. When a light-emitting diode is switch on, electrons are able to recombine with holes within the device, releasing energy in the form of photons. An LED is often small in area (Less than 1 mm 2), LED has many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size and faster switching

Anode                      Cathode


                               Fig 2.3 Electronic Symbol of a LED

The secondary winding. Transformer can be used to vary the relative voltage of circuit or isolate them, or both. It ranges in size from thumbnail-sized used in microphones to units weighing hundreds of tons interconnecting the power grid. A wide range of transformer designs are used in electronic and electric power applications. Transformers are essential for the transmission, distribution, and utilization of electrical energy.

Primary Winding                      Secondary Winding


Fig 2.6 Circuit Symbol of a transformer

2.4       DIODES

Diodes are semiconductor devices which allow the passage of current in one direction only. The latter part of that statement applies equally to vacuum tube diodes. Diodes however are far more versatile devices than that. They are extremely versatile in fact.

Diodes can be used as voltage regulators, tuning devices in if tuned circuits, frequency multiplying devices in rf circuits, mixing devices in rf circuits, switching applications or can be used to make logic decisions in digital circuits. There are also diodes which emit “light”, of course these are known as light-emitting-diodes or LED’s. as we say diodes are extremely versatile.




Schematic Symbols for Diodes

A few schematic symbols for diodes are:




Diode     Zener      Varactor      Vacuum Tube                  LED

diode      diode                   diode


                        Figure 2.7 Schematic symbols for diodes

2.5       CAPACITOR

A capacitor is originally known as a condenser. It’s a passive two terminal electrical component used to store energy electro statically in an electric field. An ideal capacitor is characterized by single constant value, capacitance. This is the ratio of the electric charge on each conductor to the potential difference between them. The SI unit of capacitance is the farad which is equal to one coulomb per volt.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. In resonant circuits they tune radios to particular frequencies. In electric power transmission systems they stabilize voltage and power flow.




       Fig 2.8 A Capacitor






                                                Fig 2.9 Schematic Symbols for diode


2.6       TRANSISTOR

Transistor can be regarded as a type of switch, as can many electronic components. They are used in a variety of circuits and you will find that it is rare that a circuit built in a school Technology Department does not contain at least one transistor. They are central to electronics and there are two main types; NPN and PNP. Most circuits (e.g. this project design) tend to use NPN. There are hundreds of transistors which work at different voltage but all of them fall into these two categories.


There are two types of standard transistors, NPN and PNP, with different circuit symbols. The letters refers to the layers of semiconductor materials used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon. This page is mostly about NPN transistors.

B                                B

E                                E

Fig 3.17 Transistor circuit symbols

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PCB Copper Trace Finish: Materials and Plating Methods
November 11, 2017

In this article, we discuss why PCB copper traces should be plated, and we’ll review various plating materials and plating methods.

PCB Trace Plating

All traces found on external PCB layers (as opposed to internal layers) must be protected from the elements. If left unprotected, the copper will oxidize and deteriorate, making the circuit board unusable. An obvious visual sign of corroded copper is its color—it will be green. One famous example of copper oxidation is the Statue of Liberty. PCB copper plating—also known as copper coating, copper finish, and surface finish—has two essential functions: (1) to protect the exposed copper circuitry, and (2) to provide a solderable surface when assembling (soldering) components to the PCB. A variety of PCB copper plating options exist, and each carries its own advantages and disadvantages.



Hot air solder leveling (HASL), is known as the tried-and-true copper plating method. This process works by dipping a board in molten solder and then leveling it off with a hot air knife, hence its name.

HASL is known for being the least expensive type of PCB surface finish, for being widely available, and for being very economical. Other advantages of using HASL include being able to easily rework the copper finish, providing a long copper finish shelf life, and serving as an ideal option for through-hole and/or larger SMT components on your PCB. However, you might run into problems if your board uses either SOIC or small SMT components.

Some other disadvantages include having uneven surfaces, possible solder bridging, plugged or reduced plated through-holes, and, of course, HASL uses lead, so this option isn’t viable for projects requiring RoHS-compliance. If your project does indeed require RoHS-compliance, you might need to consider using lead-free HASL. Lead-free HASL is a process similar to HASL only without the lead, specifically the tin-lead solder. Materials used, in place of the lead, are tin-copper, tin-nickel, or tin-copper-nickel germanium. Although this lead-free HASL process is an economical one that offers RoHS compliance, it’s similar to the regular HASL process in the sense that it’s not ideal for smaller components.


Figure 1. Example of HASL (Hot Air Solder Leveling) copper plating. Image courtesy of Sunstone.com.


Immersion Tin

Immersion coating methods utilize a chemical process for depositing a flat metal layer directly on the copper traces. Besides providing a flat surface for parts to be soldered to, tin immersion does not require the use of lead; therefore, this process yields a RoHS-compliant PCB surface. Unfortunately, the use of tin allows for the possibility of tin whiskers (see figure below).


Figure 2. Example of tin whiskers. Image courtesy of PCBheavan.com.



OSP (Organic Solderability Preservative) is a process that protects the copper surface from oxidation. According to smta.org (slide 15), “OSP is applied through chemical adsorption on the copper surface – no metal to metal displacement.” In addition to providing a lead-free flat surface, this process is advertised as being a low cost and a simple process that is very eco-friendly. Known disadvantages of using OSP include: not being the ideal choice for plated through-holes or plated-vias, having a short shelf life, and may cause issues with ICT (in-circuit testing).



The ENIG (Electroless Nickel Immersion Gold) finish has historically been the best fine-pitch (flat) surface and lead-free option worldwide, according to multicircuits.com. ENIG is a two-step process that layers a thin coating of gold over a thin coating of nickel. The nickel serves as a barrier to the copper and is the surface to which the components are actually soldered to while the gold protects the nickel during storage. Despite the fact that this coating process yields a long shelf life and is good for plated through holes, it is a complicated and an expensive process (remember that it’s a two-step process) that is not re-workable and is known to cause signal loss in RF circuits.


Figure 3. ENIG finish. Image courtesy of internationalcircuits.com


Hard Gold

Hard gold, technically known as hard electrolytic gold, consists of a layer of gold plated over a coating of nickel. Hard gold is known for being exceptionally durable and is often used in high-wear areas such as edge connector fingers. According to bayareacircuits.com, the gold is typically 98% pure 24-carat gold with an application thickness of 30 to 50 microinches deep. However, because of its high cost and its relatively poor solderability, hard gold is not generally applied to solderable areas.


Carbon Ink

Using carbon ink in place of hard gold is an option that offers lower costs and high robustness. According to bestpcbs.com, using carbon ink reduces material costs by replacing gold with carbon, and reduces process costs by “replacing the electrolytic bath with a simple screen-printing process.” And regarding robustness, “Tests have shown that a typical carbon ink is hard enough to withstand >1 million pushbutton operations (keypad) or 100 insertion operations … (edge connector) without showing wear or increased resistance.”  However, it has been noted, again from bestpcbs.com, that “carbon inks must have good viscosity stability for warmer climates and require good printing properties to give even coverage over the copper pads.” Another disadvantage is that the cured carbon ink must be able to withstand process steps including “solvent cleaning and soldering without loss of adhesion and conductivity.”


Figure 4. Carbon ink finish. Image courtesy of bestpcbs.com


IPC Standards for Surface Plating

IPC provides standards for final finish, surface plating, and coating thickness requirements (see table below).


Figure 5. IPC standards for surface plating requirements. Image courtesy of ipc.org (click to enlarge).


In Conclusion

Bare PCB copper traces should always be coated with an anti-corrosion surface finish for protecting the exposed copper from oxidization and deterioration. Although many surface plating options are available, it’s in your best interest to research which one is most applicable for each individual design and end-use application.

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weapon of mass destruction media coverage, public perception, in popular culture and common hazard symbols..
May 21, 2017

In 2004, the Center for International and Security Studies at Maryland (CISSM) released a report[54] examining the media’s coverage of WMD issues during three separate periods: nuclear weapons tests by India and Pakistan in May 1998; the U.S. announcement of evidence of a North Korean nuclear weapons program in October 2002; and revelations about Iran’s nuclear program in May 2003. The CISSM report notes that poor coverage resulted less from political bias among the media than from tired journalistic conventions. The report’s major findings were that:

Most media outlets represented WMD as a monolithic menace, failing to adequately distinguish between weapons programs and actual weapons or to address the real differences among chemical, biological, nuclear, and radiological weapons.
Most journalists accepted the Bush administration’s formulation of the “War on Terror” as a campaign against WMD, in contrast to coverage during the Clinton era, when many journalists made careful distinctions between acts of terrorism and the acquisition and use of WMD.
Many stories stenographically reported the incumbent administration’s perspective on WMD, giving too little critical examination of the way officials framed the events, issues, threats, and policy options.
Too few stories proffered alternative perspectives to official line, a problem exacerbated by the journalistic prioritizing of breaking-news stories and the “inverted pyramid” style of storytelling.
In a separate study published in 2005,[55] a group of researchers assessed the effects reports and retractions in the media had on people’s memory regarding the search for WMD in Iraq during the 2003 Iraq War. The study focused on populations in two coalition countries (Australia and the United States) and one opposed to the war (Germany). Results showed that U.S. citizens generally did not correct initial misconceptions regarding WMD, even following disconfirmation; Australian and German citizens were more responsive to retractions. Dependence on the initial source of information led to a substantial minority of Americans exhibiting false memory that WMD were indeed discovered, while they were not. This led to three conclusions:

The repetition of tentative news stories, even if they are subsequently disconfirmed, can assist in the creation of false memories in a substantial proportion of people.
Once information is published, its subsequent correction does not alter people’s beliefs unless they are suspicious about the motives underlying the events the news stories are about.
When people ignore corrections, they do so irrespective of how certain they are that the corrections occurred.
A poll conducted between June and September 2003 asked people whether they thought evidence of WMD had been discovered in Iraq since the war ended. They were also asked which media sources they relied upon. Those who obtained their news primarily from Fox News were three times as likely to believe that evidence of WMD had been discovered in Iraq than those who relied on PBS and NPR for their news, and one third more likely than those who primarily watched CBS.
In 2006 Fox News reported the claims of two Republican lawmakers that WMDs had been found in Iraq,[57] based upon unclassified portions of a report by the National Ground Intelligence Center. Quoting from the report, Senator Rick Santorum said “Since 2003, coalition forces have recovered approximately 500 weapons munitions which contain degraded mustard or sarin nerve agent”. According to David Kay, who appeared before the U.S. House Armed Services Committee to discuss these badly corroded munitions, they were leftovers, many years old, improperly stored or destroyed by the Iraqis.[58] Charles Duelfer agreed, stating on NPR’s Talk of the Nation: “When I was running the ISG – the Iraq Survey Group – we had a couple of them that had been turned in to these IEDs, the improvised explosive devices. But they are local hazards. They are not a major, you know, weapon of mass destruction.”[59]

Later, wikileaks would show that WMDs of these kinds continued to be found as the Iraqi occupation continued.[60]

Many news agencies, including Fox News, reported the conclusions of the CIA that, based upon the investigation of the Iraq Survey Group, WMDs are yet to be found in Iraq.
Awareness and opinions of WMD have varied during the course of their history. Their threat is a source of unease, security, and pride to different people. The anti-WMD movement is embodied most in nuclear disarmament, and led to the formation of the British Campaign for Nuclear Disarmament in 1957.

In order to increase awareness of all kinds of WMD, in 2004 the nuclear physicist and Nobel Peace Prize winner Joseph Rotblat inspired the creation of The WMD Awareness Programme[63] to provide trustworthy and up to date information on WMD worldwide.

In 1998 University of New Mexico’s Institute for Public Policy released their third report[64] on U.S. perceptions – including the general public, politicians and scientists – of nuclear weapons since the breakup of the Soviet Union. Risks of nuclear conflict, proliferation, and terrorism were seen as substantial.

While maintenance of the U.S. nuclear arsenal was considered above average in importance, there was widespread support for a reduction in the stockpile, and very little support for developing and testing new nuclear weapons.

Also in 1998, but after the UNM survey was conducted, nuclear weapons became an issue in India’s election of March,[65] in relation to political tensions with neighboring Pakistan. Prior to the election the Bharatiya Janata Party (BJP) announced it would “declare India a nuclear weapon state” after coming to power.

BJP won the elections, and on 14 May, three days after India tested nuclear weapons for the second time, a public opinion poll reported that a majority of Indians favored the country’s nuclear build-up.[citation needed]

On 15 April 2004, the Program on International Policy Attitudes (PIPA) reported[66] that U.S. citizens showed high levels of concern regarding WMD, and that preventing the spread of nuclear weapons should be “a very important U.S. foreign policy goal”, accomplished through multilateral arms control rather than the use of military threats.

A majority also believed the United States should be more forthcoming with its biological research and its Nuclear Non-Proliferation Treaty commitment of nuclear arms reduction.

A Russian opinion poll conducted on 5 August 2005 indicated half the population believes new nuclear powers have the right to possess nuclear weapons.[67] 39% believes the Russian stockpile should be reduced, though not fully eliminated.
Weapons of mass destruction and their related impacts have been a mainstay of popular culture since the beginning of the Cold War, as both political commentary and humorous outlet. The actual phrase “weapons of mass destruction” has been used similarly and as a way to characterise any powerful force or product since the Iraqi weapons crisis in the lead up to the Coalition invasion of Iraq in 2003.
Weapons of mass destruction and their related impacts have been a mainstay of popular culture since the beginning of the Cold War, as both political commentary and humorous outlet. The actual phrase “weapons of mass destruction” has been used similarly and as a way to characterise any powerful force or product since the Iraqi weapons crisis in the lead up to the Coalition invasion of Iraq in 2003.
The international radioactivity symbol (also known as trefoil) first appeared in 1946, at the University of California, Berkeley Radiation Laboratory. At the time, it was rendered as magenta, and was set on a blue background.[68]

It is drawn with a central circle of radius R, the blades having an internal radius of 1.5R and an external radius of 5R, and separated from each other by 60°.[69] It is meant to represent a radiating atom.

The International Atomic Energy Agency found that the trefoil radiation symbol is unintuitive and can be variously interpreted by those uneducated in its meaning; therefore, its role as a hazard warning was compromised as it did not clearly indicate “danger” to many non-Westerners and children who encountered it. As a result of research, a new radiation hazard symbol was developed in 2007 to be placed near the most dangerous parts of radiation sources featuring a skull, someone running away, and using a red rather than yellow background.[70]

The red background is intended to convey urgent danger, and the sign is intended to be used on equipment where very strong radiation fields can be encountered if the device is dismantled or otherwise tampered with. The intended use of the sign is not in a place where the normal user will see it, but in a place where it will be seen by someone who has started to dismantle a radiation-emitting device or equipment. The aim of the sign is to warn people such as scrap metal workers to stop work and leave the area.[71]

Biological weaponry/hazard symbol Edit
Developed by Dow Chemical company in the 1960s for their containment products.[72]

According to Charles Dullin, an environmental-health engineer who contributed to its development:[69]

We wanted something that was memorable but meaningless, so we could educate people as to what it means.

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Have you heard about weapon of mass destruction ????
May 21, 2017

A weapon of mass destruction (WMD) is a nuclear, radiological, chemical, biological or other weapon that can kill and bring significant harm to a large number of humans or cause great damage to human-made structures (e.g., buildings), natural structures (e.g., mountains), or the biosphere. The scope and usage of the term has evolved and been disputed, often signifying more politically than technically. Originally coined in reference to aerial bombing with chemical explosives, since World War II it has come to refer to large-scale weaponry of other technologies, such as chemical, biological, radiological, or nuclear.
The first use of the term “weapon of mass destruction” on record is by Cosmo Gordon Lang, Archbishop of Canterbury, in 1937 in reference to the aerial bombardment of Guernica, Spain:

Who can think at this present time without a sickening of the heart of the appalling slaughter, the suffering, the manifold misery brought by war to Spain and to China? Who can think without horror of what another widespread war would mean, waged as it would be with all the new weapons of mass destruction?[1]

At the time, nuclear weapons had not been developed. Japan conducted research on biological weapons (see Unit 731),[2] and chemical weapons had seen wide battlefield use in World War I. They were outlawed by the Geneva Protocol of 1925.[3] Italy used mustard gas against civilians and soldiers in Ethiopia in 1935–36.[4]

Following the atomic bombings of Hiroshima and Nagasaki that ended World War II and during the Cold War, the term came to refer more to non-conventional weapons. The application of the term to specifically nuclear and radiological weapons is traced by William Safire to the Russian phrase “Оружие массового поражения” – oruzhiye massovogo porazheniya (weapons of mass destruction).

He credits James Goodby (of the Brookings Institution) with tracing what he considers the earliest known English-language use soon after the nuclear bombing of Hiroshima and Nagasaki (although it is not quite verbatim): a communique from a 15 November 1945, meeting of Harry Truman, Clement Attlee and Mackenzie King (probably drafted by Vannevar Bush, as Bush claimed in 1970) referred to “weapons adaptable to mass destruction.”

That exact phrase, says Safire, was also used by Bernard Baruch in 1946 (in a speech at the United Nations probably written by Herbert Bayard Swope).[5] The phrase found its way into the very first resolution adopted by the United Nations General assembly in January 1946 in London, which used the wording “the elimination from national armaments of atomic weapons and of all other weapons adaptable to mass destruction.”[6] The resolution also created the Atomic Energy Commission (predecessor of the International Atomic Energy Agency (IAEA)).

An exact use of this term was given in a lecture “Atomic Energy as an Atomic Problem” by J. Robert Oppenheimer. The lecture was delivered to the Foreign Service and the State Department, on 17 September 1947. The lecture is reprinted in The Open Mind (New York: Simon & Schuster, 1955).

It is a very far reaching control which would eliminate the rivalry between nations in this field, which would prevent the surreptitious arming of one nation against another, which would provide some cushion of time before atomic attack, and presumably therefore before any attack with weapons of mass destruction, and which would go a long way toward removing atomic energy at least as a source of conflict between the powers.

The term was also used in the introduction to the hugely influential U.S. government document known as NSC-68 written in April 1950.[7]

During a speech at Rice University on 12 September 1962, President John F. Kennedy spoke of not filling space “with weapons of mass destruction, but with instruments of knowledge and understanding.”[8] The following month, during a televised presentation about the Cuban Missile Crisis on 22 October 1962, Kennedy made reference to “offensive weapons of sudden mass destruction.”[9]
An early use of the exact phrase in an international treaty was in the Outer Space Treaty of 1967, but no definition was provided.

Evolution of its use Edit
During the Cold War, the term “weapons of mass destruction” was primarily a reference to nuclear weapons. At the time, in the West the euphemism “strategic weapons” was used to refer to the American nuclear arsenal, which was presented as a necessary deterrent against nuclear or conventional attack from the Soviet Union under Mutual Assured Destruction.

Subsequent to Operation Opera, the destruction of a pre-operational nuclear reactor inside Iraq by the Israeli Air Force, the Israeli prime minister, Menachem Begin, countered criticism by saying that “on no account shall we permit an enemy to develop weapons of mass destruction against the people of Israel.” This policy of pre-emptive action against real or perceived weapons of mass destruction became known as the Begin Doctrine.

The term “weapons of mass destruction” continued to see periodic use, usually in the context of nuclear arms control; Ronald Reagan used it during the 1986 Reykjavík Summit, when referring to the 1967 Outer Space Treaty.[10] Reagan’s successor, George H.W. Bush, used the term in an 1989 speech to the United Nations, primarily in reference to chemical arms.[11]

The end of the Cold War reduced U.S. reliance on nuclear weapons as a deterrent, causing it to shift its focus to disarmament. With the 1990 invasion of Kuwait and 1991 Gulf War, Iraq’s nuclear, biological, and chemical weapons programs became a particular concern of the first Bush Administration.[12] Following the war, Bill Clinton and other western politicians and media continued to use the term, usually in reference to ongoing attempts to dismantle Iraq’s weapons programs.[citation needed]

After the 11 September 2001 attacks and the 2001 anthrax attacks in the United States, an increased fear of nonconventional weapons and asymmetrical warfare took hold in many countries. The fear reached a crescendo with the 2002 Iraq disarmament crisis and the alleged existence of weapons of mass destruction in Iraq that became the primary justification for the 2003 invasion of Iraq. However, American forces found none in Iraq. (Old stockpiles of chemical munitions including sarin and mustard agents were found, but all were considered to be unusable because of corrosion.)[13] Iraq, however, declared a chemical weapons stockpile in 2009. The stockpile contained mainly chemical precursors, but some warheads remained usable.[14]
Because of its prolific use and (worldwide) public profile during this period, the American Dialect Society voted “weapons of mass destruction” (and its abbreviation, “WMD”) the word of the year in 2002,[15] and in 2003 Lake Superior State University added WMD to its list of terms banished for “Mis-use, Over-use and General Uselessness”.[16]

In its criminal complaint against the main suspect of the Boston Marathon bombing of 15 April 2013, the FBI refers to a pressure-cooker improvised bomb as a “weapon of mass destruction.”[17]
The most widely used definition of “weapons of mass destruction” is that of nuclear, biological, or chemical weapons (NBC) although there is no treaty or customary international law that contains an authoritative definition. Instead, international law has been used with respect to the specific categories of weapons within WMD, and not to WMD as a whole. While nuclear, chemical and biological weapons are regarded as the three major types of WMDs,[18] some analysts have argued that radiological materials as well as missile technology and delivery systems such as aircraft and ballistic missiles could be labeled as WMDs as well.[18]

The abbreviations NBC (for nuclear, biological and chemical) or CBR (chemical, biological, radiological) are used with regards to battlefield protection systems for armored vehicles, because all three involve insidious toxins that can be carried through the air and can be protected against with vehicle air filtration systems.

However, there is an argument that nuclear and biological weapons do not belong in the same category as chemical and “dirty bomb” radiological weapons, which have limited destructive potential (and close to none, as far as property is concerned), whereas nuclear and biological weapons have the unique ability to kill large numbers of people with very small amounts of material, and thus could be said to belong in a class by themselves.

The NBC definition has also been used in official U.S. documents, by the U.S. President,[19][20] the U.S. Central Intelligence Agency,[21] the U.S. Department of Defense,[22][23] and the U.S. Government Accountability Office.[24]

Other documents expand the definition of WMD to also include radiological or conventional weapons. The U.S. military refers to WMD as:

Chemical, biological, radiological, or nuclear weapons capable of a high order of destruction or causing mass casualties and exclude the means of transporting or propelling the weapon where such means is a separable and divisible part from the weapon. Also called WMD.[25]
This may also refer to nuclear ICBMs (intercontinental ballistic missiles).

The significance of the words separable and divisible part of the weapon is that missiles such as the Pershing II and the SCUD are considered weapons of mass destruction, while aircraft capable of carrying bombloads are not.

In 2004, the United Kingdom’s Butler Review recognized the “considerable and long-standing academic debate about the proper interpretation of the phrase ‘weapons of mass destruction’”. The committee set out to avoid the general term but when using it, employed the definition of United Nations Security Council Resolution 687, which defined the systems which Iraq was required to abandon:

“Nuclear weapons or nuclear-weapons-usable material or any sub-systems or components or any research, development, support or manufacturing facilities relating to [nuclear weapons].
Chemical and biological weapons and all stocks of agents and all related subsystems and components and all research,development,support and manufacturing facilities.
Ballistic missiles with a range greater than 150 kilometres and related major parts, and repair and production facilities.”[26]
Chemical weapons expert Gert G. Harigel considers only nuclear weapons true weapons of mass destruction, because “only nuclear weapons are completely indiscriminate by their explosive power, heat radiation and radioactivity, and only they should therefore be called a weapon of mass destruction”. He prefers to call chemical and biological weapons “weapons of terror” when aimed against civilians and “weapons of intimidation” for soldiers.

Testimony of one such soldier expresses the same viewpoint.[27] For a period of several months in the winter of 2002–2003, U.S. Deputy Secretary of Defense Paul Wolfowitz frequently used the term “weapons of mass terror,” apparently also recognizing the distinction between the psychological and the physical effects of many things currently falling into the WMD category.

Gustavo Bell Lemus, the Vice President of Colombia, at 9 July 2001 United Nations Conference on the Illicit Trade in Small Arms and Light Weapons in All Its Aspects, quoted the Millennium Report of the UN Secretary-General to the General Assembly, in which Kofi Annan said that small arms could be described as WMD because the fatalities they cause “dwarf that of all other weapons systems – and in most years greatly exceed the toll of the atomic bombs that devastated Hiroshima and Nagasaki”.[28]

An additional condition often implicitly applied to WMD is that the use of the weapons must be strategic. In other words, they would be designed to “have consequences far outweighing the size and effectiveness of the weapons themselves”.[29] The strategic nature of WMD also defines their function in the military doctrine of total war as targeting the means a country would use to support and supply its war effort, specifically its population, industry, and natural resources.

Within U.S. civil defense organizations, the category is now Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNE), which defines WMD as:

(1) Any explosive, incendiary, poison gas, bomb, grenade, or rocket having a propellant charge of more than four ounces [113 g], missile having an explosive or incendiary charge of more than one-quarter ounce [7 g], or mine or device similar to the above. (2) Poison gas. (3) Any weapon involving a disease organism. (4) Any weapon that is designed to release radiation at a level dangerous to human life.[30]
Military Edit
For the general purposes of national defense,[31] the U.S. Code[32] defines a weapon of mass destruction as:

any weapon or device that is intended, or has the capability, to cause death or serious bodily injury to a significant number of people through the release, dissemination, or impact of:
toxic or poisonous chemicals or their precursors
a disease organism
radiation or radioactivity[33]
For the purposes of the prevention of weapons proliferation,[34] the U.S. Code defines weapons of mass destruction as “chemical, biological, and nuclear weapons, and chemical, biological, and nuclear materials used in the manufacture of such weapons.”[35]

Criminal (civilian) Edit
For the purposes of U.S. criminal law concerning terrorism,[36] weapons of mass destruction are defined as:

any “destructive device” defined as any explosive, incendiary, or poison gas – bomb, grenade, rocket having a propellant charge of more than four ounces, missile having an explosive or incendiary charge of more than one-quarter ounce, mine, or device similar to any of the devices described in the preceding clauses[37]
any weapon that is designed or intended to cause death or serious bodily injury through the release, dissemination, or impact of toxic or poisonous chemicals, or their precursors
any weapon involving a biological agent, toxin, or vector
any weapon that is designed to release radiation or radioactivity at a level dangerous to human life[38]
The Federal Bureau of Investigation’s definition is similar to that presented above from the terrorism statute:[39]

any “destructive device” as defined in Title 18 USC Section 921: any explosive, incendiary, or poison gas – bomb, grenade, rocket having a propellant charge of more than four ounces, missile having an explosive or incendiary charge of more than one-quarter ounce, mine, or device similar to any of the devices described in the preceding clauses
any weapon designed or intended to cause death or serious bodily injury through the release, dissemination, or impact of toxic or poisonous chemicals or their precursors
any weapon involving a disease organism
any weapon designed to release radiation or radioactivity at a level dangerous to human life
any device or weapon designed or intended to cause death or serious bodily injury by causing a malfunction of or destruction of an aircraft or other vehicle that carries humans or of an aircraft or other vehicle whose malfunction or destruction may cause said aircraft or other vehicle to cause death or serious bodily injury to humans who may be within range of the vector in its course of travel or the travel of its debris.
Indictments and convictions for possession and use of WMD such as truck bombs,[40] pipe bombs,[41] shoe bombs,[42] and cactus needles coated with a biological toxin[43] have been obtained under 18 USC 2332a.

As defined by 18 USC §2332 (a), a Weapon of Mass Destruction is:

(a) any destructive device as defined in section 921 of the title;
(B) any weapon that is designed or intended to cause death or serious bodily injury through the release, dissemination, or impact of toxic or poisonous chemicals, or their precursors;
(C) any weapon involving a biological agent, toxin, or vector (as those terms are defined in section 178 of this title); or
(D) any weapon that is designed to release radiation or radioactivity at a level dangerous to human life;
Under the same statute, conspiring, attempting, threatening, or using a Weapon of Mass Destruction may be imprisoned for any term of years or for life, and if resulting in death, be punishable by death or by imprisonment for any terms of years or for life. They can also be asked to pay a maximum fine of $250,000.[44]
The Washington Post reported on 30 March 2006: “Jurors asked the judge in the death penalty trial of Zacarias Moussaoui today to define the term ‘weapons of mass destruction’ and were told it includes airplanes used as missiles”. Moussaoui was indicted and tried for the use of airplanes as WMD.

The surviving Boston Marathon bombing perpetrator, Dzhokhar Tsarnaev, was charged in June 2013 with the federal offense of “use of a weapon of mass destruction” after he and his brother Tamerlan Tsarnaev allegedly placed crude shrapnel bombs, made from pressure cookers packed with ball bearings and nails, near the finish line of the Boston Marathon. He was convicted in April 2015. The bombing resulted in three deaths and at least 264 injuries.
The development and use of WMD is governed by several international conventions and treaties, although not all countries have signed and ratified them:

Partial Test Ban Treaty
Outer Space Treaty
Nuclear Non-Proliferation Treaty (NPT)
Seabed Arms Control Treaty
Comprehensive Test Ban Treaty (CTBT, has not entered into force as of 2015)
Biological and Toxin Weapons Convention (BWC)
Chemical Weapons Convention (CWC)
The only country to have used a nuclear weapon in war is the United States, which dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki during World War II. There are eight countries that have declared they possess nuclear weapons and are known to have tested a nuclear weapon, only five of which are members of the NPT. The eight are China, France, India, North Korea, Pakistan, Russia, the United Kingdom, and the United States.

Israel is considered by most analysts to have nuclear weapons numbering in the low hundreds as well, but maintains an official policy of nuclear ambiguity, neither denying nor confirming its nuclear status.

South Africa developed a small nuclear arsenal in the 1980s but disassembled them in the early 1990s, making it the only country to have fully given up an independently developed nuclear weapons arsenal. Belarus, Kazakhstan, and Ukraine inherited stockpiles of nuclear arms following the break-up of the Soviet Union, but relinquished them to the Russian Federation.

Countries with access to nuclear weapons through nuclear sharing agreements include Belgium, Germany, Italy, the Netherlands, and Turkey.
Due to the indiscriminate impact of WMD, the fear of a WMD attack has shaped political policies and campaigns, fostered social movements, and has been the central theme of many films. Support for different levels of WMD development and control varies nationally and internationally. Yet understanding of the nature of the threats is not high, in part because of imprecise usage of the term by politicians and the media.

An atomic-bomb blueprint
Fear of WMD, or of threats diminished by the possession of WMD, has long been used to catalyze public support for various WMD policies. They include mobilization of pro- and anti-WMD campaigners alike, and generation of popular political support. The term WMD may be used as a powerful buzzword[45] or to generate a culture of fear.[46] It is also used ambiguously, particularly by not distinguishing among the different types of WMD.[47]

A television commercial called Daisy, promoting Democrat Lyndon Johnson’s 1964 presidential candidacy, invoked the fear of a nuclear war and was an element in Johnson’s subsequent election.

More recently, the threat of potential WMD in Iraq was used by President George W. Bush as justification for the 2003 invasion of Iraq.[48] Broad reference to Iraqi WMD in general was seen as an element of President Bush’s arguments.[47] The claim that Iraq possessed Weapons of Mass Destruction (WMD) led to the invasion of Iraq in 2003 by Coalition forces.

Over 500 munitions were discovered throughout Iraq since 2003 containing chemical agents mustard and Sarin gas, produced in the 1980s and no longer usable as originally intended.[49]

In 2004, Polish troops found nineteen 1980s-era rocket warheads, thwarting an attempt by militants to buy them at $5000 each. Some of the rockets contained extremely deteriorated nerve agent.[50]

The American Heritage Dictionary defines a weapon of mass destruction as: “a weapon that can cause widespread destruction or kill large numbers of people, especially a nuclear, chemical, or biological weapon.”[51] In other words, it does not have to be nuclear, biological or chemical (NBC). For example, the terrorist for the Boston Marathon bombings was charged under United States law 18 U.S.C. 2332A[52] for using a weapon of mass destruction[53] and that was a pressure cooker bomb. In other words, it was a weapon that caused large-scale death and destruction, without being an NBC weapon.

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Some Hidden Things About The Universe
May 17, 2017

××he Universe Is Old (Really Old)

he universe began with the Big ang, and is estimated to be pproximately 13.7 billion years old

plus or minus 130 million years).

stronomers calculated this figure by easuring the composition of matter nd energy density in the universe, hich enabled them to determine ow fast the universe expanded in he past. As a result, researchers ould turn back the hands of time nd pinpoint when the Big Bang ccurred. The time in between that xplosion and now makes up the age f the universe

×× he Universe Is Getting Bigger

n the 1920s, astronomer Edwin ubble made the revolutionary iscovery that the universe is not tatic, but rather is expanding. But, it as long thought that the gravity of atter in the universe would slow his expansion or even cause it to ontract.

n 1998, the Hubble Space Telescope tudied very distant supernovas and ound that, a long time ago, the niverse was expanding more slowly han it is today. This puzzling iscovery suggested that an nexplicable force, called dark energy, s driving the accelerating expansion f the universe. [ Full Story ]

hile dark energy is thought to be he strange force that is pulling the osmos apart at ever-increasing peeds, it remains one of the reatest mysteries in science ecause its detection remains lusive to scientists.

×× he Universe’s Growth Spurt Is ccelerating

ysterious dark energy is not only hought to be driving the expansion f the universe, it appears to be ulling the cosmos apart at ever-ncreasing speeds. In 1998, two eams of astronomers announced hat not only is the universe xpanding, but it is accelerating as ell. According to the researchers, he farther a galaxy is from Earth, the aster it is moving away.

he universe’s acceleration also onfirms Albert Einstein’s theory of eneral relativity, and lately, cientists have revived Einstein’s osmological constant to explain the trange dark energy that seems to be ounteracting gravity and causing he universe to expand at an ccelerating pace. [Full Story]

hree scientists won the 2011 Nobel rize in Physics for their 1998 iscovery that the expansion of the niverse was accelerating.

×× he Universe Is Filled With Invisible tuff

he universe is overwhelmingly made p of things that cannot be seen. In ct, the stars, planets and galaxies hat can be detected make up only 4 ercent of the universe, according to stronomers. The other 96 percent is ade up of substances that cannot e seen or easily comprehended.

hese elusive substances, called ark energy and dark matter, have ot been detected, but astronomers ase their existence on the ravitational influence that both exert n normal matter, the parts of the niverse that can be seen

×× he Universe Could Be Flat

he shape of the universe is fluenced by the struggle between he pull of gravity (based on the ensity of the matter in the universe) nd the rate of expansion. If the ensity of the universe exceeds a ertain critical value, then the niverse is “closed,” like the surface f a sphere. This implies that the niverse is not infinite but has no nd. In this case, the universe will ventually stop expanding and start ollapsing in on itself, in an event nown as the “Big Crunch.”

f the density of the universe is less han the critical density value, then he shape of the universe is “open,” ke the surface of a saddle. In this ase, the universe has no bounds nd will continue to expand forever

he Universe Has Echoes of Its Birth

he cosmic microwave background

made up of light echoes left over om the Big Bang that created the niverse 13.7 billion years ago. This lic of the Big Bang explosion hangs round the universe as a pocked veil f radiation.

he European Space Agency’s lanck mission mapped the entire ky in microwave light to reveal new lues about how the universe began. lanck’s observations are the most recise views of the cosmic icrowave background ever btained. Scientists are hoping to se data from the mission to settle ome of the most debated questions

cosmology, such as what appened immediately after the niverse was form seen

×× here May Be More Universes

he idea that we live in a multiverse,

which our universe is one of many, omes from a theory called eternal flation, which suggests that shortly fter the Big Bang, space-time xpanded at different rates in different laces. According to the theory, this ave rise to bubble universes that ould function with their own eparate laws of physics.

he concept is controversial and had een purely hypothetical until recent tudies searched for physical arkers of the multiverse theory in e cosmic microwave background, hich is a relic of the Big Bang that ervades our universe. [Full Story]

esearchers searched the best vailable observations of the cosmic icrowave background for signs of ubble universe collisions, but didn’t nd anything conclusive. If two niverses had collided, the searchers say, it would have left a ircular pattern behind in the cosmic icrowave background

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Mobile Phones: A Necessary Evil and friend also.
May 8, 2017

Mobile phones have become necessity of life nowadays, but somewhere we are not using it correctly. Mobiles are technically advanced & have too many options like Hi-tech games, radio, and internet, downloading, etc. Everyone from youngsters to old aged uses mobile phones for different purposes.  But teenagers use it for texting, music, games & net surfing.
We have started to rely upon the cell phones now. With a touch alarm blows & we wake up, easy conversation is possible, reminders & notes to make you alert, social chats to remove the distance, in fact GPS for navigation. But it’s a distraction which can bring harm to us, life & property. Mobiles can damage the brain as well.
You are no more secure, as your social life will be completely destroyed. No personal distances, no privacy at all, as anyone can dig into your life through social sites. It can also leads to wrong practices also like hacking the data, damage, unwanted blank/fake calls etc.
Parents are really annoyed because of the cell phones addiction of the teen agers as they keep their phones with them everywhere like using it while dinning, studying, shopping, at schools/colleges. It has supported the wrong habits in them. Sometimes students tend to cheat in examination by taking their cell phones with them in examination centre.
The major issue attached with the cell phones is health problems. Excessive use of mobiles leads to problems like Migraines, weak eyesight, can bring damage to your brain as well. On petrol pumps mobiles are asked to be turned off, but these teen agers generally ignore it, which leads to big explosion also. Isn’t this a risk to life & property?
Look at the major negatives attached to the mobile phones.

“¢    No privacy

“¢    Threat to life & property

“¢    Health hazardous

“¢    Disturbance to life

“¢    Invitation to bad practices, etc

Still it’s a great invention which needs to be used in right ways. Mobile phones are useful in a lot of situations but make sure it should not become the controller of your life.

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touchpad how did it get loaded on my phone
May 8, 2017

Some how I got this program on my phone call touch pad I had no idea had this got up loaded on my android phone.This program is very annoying plus it takes up a lot of space. I would never ask for a program like this . I am not sure even how to explain this program. I did a search to see how to get rid of this program call touch pad. This time I got lucky and found the right form and I got the information I need.This is how I got rid of touch pad on my phone I went setting look for apps or application then I found the program and it said to unstale it . I had no problem unstaleing it. On the form some other people said it has some thing to do with the phone keyboard and it disable the factory key board and the people could not get rid of touch pad. for me it had nothing to do with the key board . it just was like a big adevertsing bill board on my phone taking a lot of space away . This was driving me nuts.How did I get it ? I have no idea last night after charging my phone it just pop on my phone. so maybe something with the charging program some how up loaded the program on my phone . what I think I do now when the phone is being charge is to turn wi-fi off I all ready have data off may this will keep programs form up loading while I am a sleep… Any one else ever had a program up load while they were sleeping or doing something else I am not talking about if your kid took your phone and up loaded a program that kind of normal
for this day of age. OK that it for now.

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Nokia phone review, first phone ever
April 28, 2017

I bought nokia in 2002 was my first phone, small cute, to call and receive call which is enough for me, this nokia is just a basic phone with low resolution  I guess was 0.4 megapixels cam. The voice is good and ring tone great from this phone was really satisfactory but its sound recorder more than phone it was able to record bout 20 seconds feature but I no internet ability that time , it had 3.5 MB memory, nokia phone did have a Bluetooth that time. Nokia phone supported a limited number of games that time. The screen was really small ready background were limited


It was also cheap its price is 300 dollars. It did not support Wireless LAN or even 3G, there was also radio. Its built in

I was fascinated with its feature for the game . The battery life was so long, nokia made a phone with battery that sustain for 6 days or week maybe even. The keypad comes with backlit with white light for each button and were big enough to press comfortably. but never use browser service since that needs net. However, the I loved the design, its was orange and blue and pink in color, the keypad were strong and do not stuck like todays phones and resistant to wear. It did sustain lots of drops

Nokia is my favorite brand myabe because its my first phone, or maybe its true best brand ever, but now i prefer other phone only due to the net, other features are best in nokia, but the net serving is not something that i tried there with nokia, i have to say nokia prices are competitive and last long with kids mostly

It is great brand and i like it even if I use ohter phone for other features.

Nokia phone review, first phone ever

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