Environmental care to the technological impact - Examples

Environmental care to the technological impact - Technology impact

The application of technology (in general) often results in unavoidable environmental impacts, which according to the I=PAT equation is measured as resource use or pollution generated per unit GDP. Environmental impacts caused by the application of technology are often perceived as unavoidable for several reasons. First, given that the purpose of many technologies is to exploit, control, or otherwise “improve” upon nature for the perceived benefit of humanity while at the same time the myriad of processes in nature have been optimized and are continually adjusted by evolution, any disturbance of these natural processes by technology is likely to result in negative environmental consequences. Second, the conservation of mass principle and the first law of thermodynamics dictate that whenever material resources or energy are moved around or manipulated by technology, environmental consequences are inescapable. Third, according to the second law of the thermodinamics, order can be increased within a system (such as the human economy) only by increasing disorder or entropy outside the system (i.e., the environment). Thus, technologies can create “order” in the human economy (i.e., order as manifested in buildings, factories, transportation networks, communication systems, etc.) only at the expense of increasing “disorder” in the environment. According to a number of studies, increased entropy is likely to be correlated to negative environmental impacts.

Environmental care to the technological impact - Environmental impact in China

China is the most populated country in the world whith lot of technological devices, and this causes lot of enviromental problems. Here i have found a video of how technology affect our environment, it explains us the impact of technology in the enviroment, in the case in China.

Environmental care to the technological impact - Women an the enviroment

In the early 1970s an interest in women and their connection with the environment was sparked, largely by a book written by Esther Boserup  entitled, Woman's Role in Economic Development. Starting in the 1980s, policy makers and governments became more mindful of the connection between the environment and gender issues. Changes began to be made regarding natural resource and environmental management with the specific role of women in mind. According to the World Bank in 1991, "Women play an essential role in the management of natural resources, including soil, water, forests and energy...and often have a profound traditional and contemporary knowledge of the natural world around them'". Whereas women were previously neglected or ignored, there was increasing attention paid to the impact of women on the natural environment and, in return, the effects the environment has on the health and well-being of women. The gender-environment relations have valuable ramifications in regard to the understanding of nature between men and women, the management and distribution of resources and responsibilities and the day-to-day life and well being of people

Environmental care to the technological impact - I=PAT

I = PAT is the lettering of a formula put forward to describe the impact of human activity on the environment.

I = P × A × T

In words:

Human Impact (I) on the environment equals the product of P= Population, A= Affluence, T= Technology. This describes how our growing population, affluence, and technology contribute toward our environmental impact, but in this part im going to explain only the technologocal impact on the enviroment.

The T variable in the I=PAT equation represents how resource intensive the production of affluence is; how much environmental impact is involved in creating, transporting and disposing of the goods, services and amenities used. Improvements in efficiency can reduce resource intensiveness, reducing the T multiplier. Since technology can affect environmental impact in many different ways, the unit for T is often tailored for the situation I=PAT is being applied to.

Enviromental impact:

Increases in efficiency can reduce overall environmental impact. However, with P increasing exponentially, T would have to decrease drastically (doubling efficiency each time the population doubles) just to maintain the same impact with the same affluence. Over the last few years, data from the World bank has shown that T has decreased and that it is likely to continue to do so in the future. .

Environmental care to the technological impact - Introduction

INTRODUCTION:

The general public believes that technology will improve health care efficiency, quality, safety, and cost. However, few people consider that these same technologies may also introduce errors and adverse events. Given that nearly 5,000 types of medical devices are used by millions of health care providers around the world, device-related problems are inevitable. While technology holds much promise, the benefits of a specific technology may not be realized due to four common pitfalls: 
       - (1) poor technology design that does not adhere to human factors and ergonomic principles,
          - (2) poor technology interface with the patient or environment,
          - (3) inadequate plan for implementing a new technology into practice,
       - (4) inadequate maintenance plan.

Electrical measurements - Electrical power

Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter P. The term wattage is used colloquially to mean "electric power in watts." The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every tseconds passing through an electric potential  difference of V is:

Electrical measurements - Magnetic field

A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude; as such it is a vector field. The magnetic field is most commonly defined in terms of the Lorentz force it exerts on moving electric charges. Magnetic field can refer to two separate but closely related fields which are denoted by the symbols B and H.

Magnetic fields are produced by moving electric charges and the intrinsic magnetic moments of elementary particles associated with a fundamental quantum property, their spin. In special relativity, electric and magnetic fields are two interrelated aspects of a single object, called theelectromagnetic tensor; the split of this tensor into electric and magnetic fields depends on the relative velocity of the observer and charge. In quantum physics, the electromagnetic field is quantized and electromagnetic interactions result from the exchange of photons.

Electrical measurements - Magnetic flux

In physics, specifically electromagnetism, the magnetic flux (often denoted Φ or Φ_B) through a surface is the component of the magnetic B field passing through that surface. The SI unit of magnetic flux is the weber (Wb) (in derived units: volt-seconds), and the CGS unit is the maxwell. Magnetic flux is usually measured with a fluxmeter, which contains measuring coils and electronics, that evaluates the change of votage in the measuring coils to calculate the magnetic flux.

  

The magnetic flux through a surface when the magnetic field is variable relies on splitting the surface into small surface elements,over which the magnetic field can be considered to be locally constant. The total flux is then a formal summation of these surface elements.

Electrical measurements - Voltage

Voltage is electric potential energy per unit charge, measured in joules per coulomb ( = volts). It is often referred to as "electric potential", which then must be distinguished from electric potential energy by noting that the "potential" is a "per-unit-charge" quantity. Like mechanical potential energy, the zero of potential can be chosen at any point, so the difference in voltage is the quantity which is physically meaningful. The difference in voltage measured when moving from point A to point B is equal to the work which would have to be done, per unit charge, against the electric field to move the charge from A to B. The voltage between the two ends of a path is the total energy required to move a small electric charge along that path, divided by the magnitude of the charge. Mathematically this is expressed as the line integral of the electric field and the time rate of change of magnetic field along that path. In the general case, both a static (unchanging) electric field and a dynamic (time-varying) electromagnetic field must be included in determining the voltage between two points.

Electrical measurements - Introduction

INTRODUCTION:
Electrical measurement often come down to either measuring current or measuring voltage. Even if you are measuring, you will be measuring the frequency of a current signal or a voltage signal and you will need to know how to measure either voltage or current. In this short lesson, we will examine those two measurements – starting with measuring voltage. However, first we should note a few common characteristics of the meters you use for those measurements.

Many times you will use a digital multimeter to measure either voltage or current. Actually, a DMM (digital multimeter) will also usually measure frequency and resistance. You should note the following about typical DMMs.

-       Polarity is important.

-       Often one of the terminals on the DMM may be co0nnected to the ground.

Robotics - Robots education

Robotics engineers develop new applications for them, and conduct research to expand the potential of robotics. Robots have become a popular educational tool. First-year computer science courses at several universities now include programming of a robot in addition to traditional software engineering-based coursework. 
Here i have found an interesting video of how a robot can be deeloped by some robotics enginners, and how they have developed among the time.

Robotics - Dynamics and kinematics

The study of motion can be divided into kinematics and dynamics. We can distinguish two types of kinematics:

        -     Direct kinematics refers to the calculation of end effector position, orientation, velocity,        and acceleration when the corresponding joint values are known.

        -      Inverse kinematics refers to the opposite case in which required joint values are calculated forgiven end effetor values, as done nin path planning.

Some special aspects of kinematics include different possibilities of performing the same movement. Once all relevant positions, velocities, and accelerations have been calculated using kinematics, methods from the field of dynamics are used to study the effect of forces upon these movements.

-       Direct dynamics refers to the calculation of accelerations in the robot once the applied forces are known. Direct dynamics is used in computer simulation of the robot.

-        Inverse dynamics refers to the calculation of the actuator forces necessary to create a prescribed end effector acceleration. This information can be used to improve the control algorithms of a robot.

In each area mentioned above, researchers strive to develop new concepts and strategies, improve existing ones, and improve the interaction between these areas. To do this, criteria for "optimal" performance and ways to optimize design, structure, and control of robots must be developed and implemented.

Robotics - How is a Robot controlled?

The mechanical structure of a robot must be controlled to perform tasks. The control of a robot involves three distinct phases – perception, processing, and action. Sensors give information about the environment or about the robot itself. This information is then processed to calculate the appropriate signals to the actuators which move the mechanical.

The processing phase can range in complexity. At a reactive level, it may translate raw sensor information directly into actuator commands. Sensor fusion may first be used to estimate parameters of interest from noisy sensor data. An immediate task is inferred from these estimates. Techniques from control theory convert the task into commands that drive the actuators.

Control systems may also have varying levels of autonomy.

1.    Direct interaction is used for haptic or tele-operated devices, and the human has nearly complete control over the robot's motion.

2.    Operator-assist modes have the operator commanding medium-to-high-level tasks, with the robot automatically figuring out how to achieve them.

3.    An autonomous robot may go for extended periods of time without human interaction. Higher levels of autonomy do not necessarily require more complex cognitive capabilities. For example, robots in assembly plants are completely autonomous, but operate in a fixed pattern.

Another classification takes into account the interaction between human control and the machine motions.

1.  Teleoperation. A human controls each movement, each machine actuator change is specified by the operator.

2.    Supervisory. A human specifies general moves or position changes and the machine decides specific movements of its actuators.

3.    Task-level autonomy. The operator specifies only the task and the robot manages itself to complete it.

4.    Full autonomy. The machine will create and complete all its tasks without human interaction.

Robotics - Power source

At present mostly batteries are used as a power source. Different types of batteries can be used as a power source for robots. They range from lead acid batteries which are safe and have relatively long shelf lives but are rather heavy to silver cadmium batteries that are much smaller in volume and are currently much more expensive. To dessign a battery powered robot, we need to take into account factors such as safety, cycle lifetime and weight. Generators, can also be used.  A tether connecting the robot to a power supply would remove the power supply from the robot entirely. This has the advantage of saving weight and space by moving all power generation and storage components elsewhere. However, this design does come with the drawback of constantly having a cable connected to the robot, which can be difficult to manage. Potential power sources could be:

·         pneumatic (compressed gases)

·          hydraulics (liquids)

·         organic garbage (through anaerobic digestion)

·         faeces (human, animal); may be interesting in a military context as faeces of small combat groups may be reused for the energy requirements of the robot assistant

Robotics - Introduction

INTRODUCTION:
Robotics is the branch of technology that deals with the design, construction, operation, and application of robots. These technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes.

The concept of creating machines that can operate autonomously dates back to classical times, but the potential of robots did not grow substantially until the 20th century. Throughout history, robotics has been often seen to mimic human behavior, and often manage tasks in a similar fashion. Today, robotics is a rapidly growing field, as technological advances continue, research, design, and building new robots serve various practical purposes, whether dosmetically, commercially, or military. 

Bipolar junction transistor - Application

The BJT remains a device that excels in some applications, such as discrete circuit design, due to the very wide selection of BJT types available, and because of its high transconductance and output resistance compared to MOSFETs. The BJT is also the choice for demanding analog circuits, especially for very high frequency  applications, such as radio-frequency circuits for wireless systems. Bipolar transistors can be combined with MOSFETs in an integrated circuit by using a BiCMOS process of wafer fabrication to create circuits that take advantage of the application strengths of both types of transistor.

Bipolar junction transistor - The BJT theory

Both types of BJT function by letting a small current input to the base control an amplified output from the collector. The result is that the transistor makes a good sitch that is controlled by its base input. In the NPN in what is called active mode, the base-emitter voltage and collector-base voltage       are positive, forward biasing the emitter-base junction and reverse-biasing the collector-base junction. In the active mode of operation, electrons are injected from the forward biased n-type emitter region into the p-type base where they diffuse as minority carriers to the reverse-biased n-type collector and are swept away by the electric field in the reverse-biased collector-base junction.

Bipolar junction transistor - Types of BJT

TYPES OF BJT :

NPN :

NPN is one of the two types of bipolar transistors, consisting of a layer of P-doped semiconductor between two N-doped layers. When there is a positive potential difference measured from the emitter of an NPN transistor to its base as well as positive potential difference measured from the base to the collector, the transistor becomes active. In this "on" state, current flows between the collector and emitter of the transistor.

PNP :

PNP consist of a layer of N-doped semiconductor between two layers of P-doped material. A small current leaving the base is amplified in the collector output. PNP transistor is "on" when its base is pulled low relative to the emitter.

Bipolar junction transistor - History

In December 1947 the point-contact transistor was invented at the laboratory called ‘Bell Telephone’ by Walter Brattain and John Bardeen under the direction of William Shockley. The junction version known as the bipolar junction transistor, invented by Shockley, enjoyed three decades as the device of choice in the design of discrete and integrated circuits. Nowadays, the use of the BJT has declined in favor of CMOS technology in the design of digital integrated circuits. 

Bipolar junction transistor - Introduction

INTRODUCTION :

A bipolar junction transistor (BJT or bipolar transistor) is a type of transistor that relies on the contact of two types of semiconductor for its operation. BJTs can be found either as individual discrete components, or in large numbers as parts of integrated circuits.

BJTs come in two types, PNP and NPN, based on the doping types of the three main terminal regions.

In typical operation, the base–emitter junction is forward biased, which means that the p-doped side of the junction is at a more positive potential than the n-doped side, and the base–collector junction is reverse biased. 

In an NPN transistor, when positive bias is applied to the base–emitter junction, the equilibrium is disturbed between the thermally generated carries and the repelling electric field of the n-doped emitter depletion region. The electrons injected from he emitter into the base region, diffuse through the base from the region of high concentration near the emitter towards the region of low concentration near the collector. The electrons in the base are called 'minority carriers' because the base is doped p-type, which makes holes the 'majority carriers' in the base.

Semiconductor diode - Shockley diode equation

The Shockley ideal diode equation ( also called the diode law) gives the I–V characteristic of an ideal diode. The Shockley ideal diode equation is:

                     
                         

        Where:

                I => is the diode current,

                I_{S =>} is the reverse bias saturation current,

                V_{D =>} is the voltage across the diode,

                V_{T =>} is the termal voltage,

                N => is the ideality factor, depends on the fabrication process and semiconductor material and in many cases is assumed to be approximately equal to 1 (thus the notation n is omitted). By setting n = 1 above, the equation reduces to the Shockley ideal diode equation.

The thermal voltage V_T ( approximately 25.85 mV at 300 K, a temperature close to "room temperature") is commonly used in device simulation software. At any temperature it is a known constant defined by:

        

                              
           where 

                 k => is the Boltzmann constant,

                 T => is the absolute temperature of the p–n junction 
                 q => is the magnitude of charge of an electron. 

Semiconductor diode - types of semiconductor diode

There are different types of p – n junctions diodes, depending often on its physical aspect of a diode.

Normal (p–n) diodes,(usually made of doped silicon or germanium) are found in CMOS integrated circuits, which include two diodes per pin and many other internal diodes.

Here i’m going to explain some of them:

Avalanche diodes:

An avalanche diode is a diode that is designed to go through avalanche breakdown at a specified reverse bias voltage. The avalanche breakdown is due to minority carriers accelerated enough to create ionization in the crystal lattice, producing more carriers which in turn create more ionization.

Cat’s whisker or cristal diodes:

A cat's-whisker detector is an antique electronic component consisting of a thin wire that lightly touches a crystal of semiconducting mineral to make a crude point-contact rectifier.

Constant current diodes:

Constant-current diode they allow a current through them to rise to a certain value, and then level off at a specific value. These devices keep the current flowing through them unchanged when the voltage changes.

Gunn diodes:

Gunn diodes are similar to tunnel diodes (made of materials such as GaAs or InP) that exhibit a region of negative differential resistance. With appropriate biasing, dipole domains form and travel across the diode, allowing high frequency microwave oscilators to be built.

Light-emiting diodes (LEDs):

A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting..

Thermal diodes:

Thermal diodes are used for conventional p–n diodes used to monitor temperature due to their varying forward voltage with temperature.

Zener diodes:

A Zener diode is a diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, "zener knee voltage", "zener voltage" or "avalanche point".

Semiconducor diode - 'p-n' juncion diode

The most basic property of a junction diode is that it conducts an electric current in one direction and blocks it in the other. This behaviour arises from the electrical characteristics of a junction, called a ‘p – n juncion’, fabricated within a semiconductor crystal. The most commonly used semiconductor material is silicon. The junction diode is useful in a wide variety of applications including the rectification of ac signals, the detection of radio signals, the conversion of solar power to electricity, and in the generation and detection of light. It also finds use in a variety of electronic circuits as a switch, as a voltage reference or even as a tunable capacitor. The p-n junction is also the basic building block of a host of other electronic devices, of which the most well-known is the junction transistor. For this reason, a study of the properties and behaviour of the p-n junction is important.

Semiconductor diodes - Electronic symblos

To diference each type of diode we use symbols. There are alternate symbols for some types of diodes, though the differences are minor.

        => Diode                  =>Light Emiting Diode (LED)
         => Photodiode           => Schottky Diode
          => Transient Voltage => Tunnel Diode
                                            Suppression (TVS)

       => Varicap                 => Zener Diode

Seiconductor diodes - Introduction

INTRODUCTION :
A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals.

However, diodes have a more complicated behavior than a simple on–off action. Semiconductor diodes begin conducting electricity only if a certain threshold voltage or cut-in voltage is present in the forward direction. The voltage drop across a forward-biased diode varies only a little with the current, and is a function of temperature.

Semiconductor diodes' nonlinear current-voltage characteristic can be tailored by varying the semiconductor materials and doping, introducing impurities into the materials. These are exploited in special-purpose diodes that perform many different function (eg: diodes are used to regulate voltage, to generate radio frequency oscillations, and to produce light). Tunnel diodes exhibit negative resistance, which makes them useful in some types of circuits.

Diodes were the first semiconductor electronic devices. The first semiconductor diodes (made in 1906) were made of mineral crystals such as galena, and nowadays they are made of sillicon.

Integrated circuit - Developments

Programmable logic devices, developed in the 1980, contain circuits whose logical function and connectivity can be programmed by the user. This allows a single chip to be programmed to implement different LSI-type functions such as logic gates, adders and registers.  

In the past, radios could not be fabricated in the same low-cost processes as microprocessors. But since 1998, a large number of radio chips have been developed using CMOS processes.  

Since the 2000s, the integration of optical functionality into silicon chips has been actively pursued in: academic research and industry, resulting like this in the successful commercialization of silicon based integrated optical transceivers combining optical devices with CMOS based electronics.

Integrated circuits - Classification

HOW CAN ICs BE CLASSIFIED?

Integrated circuits (ICs) can be classified into analog, digital and mixed-signals.

- Digital ICs are further sub-categorized as logic ICs, memory chips, interface ICs, Power Management ICs, and    programmable devides.

- Analog ICs are further sub-categorized as linear ICs and RF ICs.

- Mixed-signals ICs are further sub-categorized as data acquisition ICs and clock/timing ICs.