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Optical Transducers and Biosensors: Principles and Applications

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WEEK4

TRANSDUCER

A transducer is a device that converts an observed change (physical, chemical, or biological) into a measurable signal.

Optical Transducers

Absorption spectroscopy, fluorescence spectroscopy, luminescence, internal reflection, light scattering, surface plasmon resonance, ellipsometry, and fiber optics.

TOTAL INTERNAL REFLECTION and EVANESCENT FIELD

The refractive index n1 is larger for the incident medium than the refractive index n2 of the reflecting medium. Sin(THETA)=n2/n1. However, the electric field of the light penetrates into the second medium and is called the EVANESCENT FIELD. The evanescent field has an extension of several hundred nanometers and can be used as an optical probe if one or more additional layers are present

... Continue reading "Optical Transducers and Biosensors: Principles and Applications" »

Cold air pool atpl

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A ball is thrown horizontally from the top of a 60.0-m building and lands 100.0 m from the base Of the building. Ignore air resistance. (a) How long is the ball in the air? (b) What must have Been the initial horizontal component of the velocity? (c) What is the vertical component of the Velocity just before the ball hits the ground? (d) What is the velocity (including both the Horizontal and vertical components) of the ball just before it hits the ground?

 A team of eight dogs pulls a sled with waxed wood runners on wet snow (μs=0.14 and μk=0.10). The dogs have average masses of 19.0 kg, and the loaded sled with its rider has a mass of 210 Kg. (a) Calculate the magnitude of the acceleration starting from rest if each dog exerts an Average
... Continue reading "Cold air pool atpl" »

Electrical Fundamentals

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EQUATIONS

EMF and Potential Difference

emf = E/Q
V = emf -Ir
For negligible r, V = emf

Resistance

R = pL/A

CURRENT

Rate of flow of charge.
Measured using an ammeter.

POTENTIAL DIFFERENCE (P.D.)

Work done in moving a unit charge between two points.
(Work is done when a charge flows through a component, transferring energy to it.)

RESISTANCE

When a potential difference is applied across a component, a current will flow. The amount of current for a particular potential difference depends on the resistance.

OHMIC CONDUCTORS

An ohmic conductor obeys Ohm's Law.
Ohm's Law: Provided constant physical conditions, the current through an ohmic conductor is directly proportional to the potential difference across it.
IV Graph: A straight line indicates constant resistance.
... Continue reading "Electrical Fundamentals" »

Understanding Pendulums, Fluid Pressure, and Molecular Forces

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Understanding Pendulums

State the following terms:

  • Pendulum
  • Simple pendulum
  • Conical pendulum

Ans: A tiny mass (assumed to be a point object and called a bob) connected to a long, flexible, massless, inextensible string, and suspended to a rigid support is called a pendulum.

If a tiny mass (assumed to be a point object and called a bob) connected to a long, flexible, massless, inextensible string, and suspended to a rigid support is made to oscillate in a single vertical plane, it is said to be a simple pendulum.

A tiny mass (assumed to be a point object and called a bob) connected to a long, flexible, massless, inextensible string, and suspended to a rigid support revolves in such a way that the string moves along the surface of a right circular cone... Continue reading "Understanding Pendulums, Fluid Pressure, and Molecular Forces" »

Fluid Mechanics Quiz

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Measurement of Pressure Losses in Pipes

1. Measurement of pressure losses in pipes under pressure can be made with: Piezometers

Flow Number and Linear Losses Factor

2. The flow number a is expressed in units: This value is dimensionless.

3. The linear losses factor f can be determined on the basis of: Relative roughness and Reynolds Number.

Orifice and Pump Head

4. The ISA orifice can be used to measure: Flow rate.

5. The pump head can be determined from: Bernoulli equation.

Absolute Roughness and Outlet Pressure

7. Absolute roughness can be determined: From Colebrook-White's formula.

8. The outlet pressure in the nozzle depends on: Flow rate in the nozzle.

Hydrostatic Pressure and Force

9. The unit of hydrostatic pressure in the SI system: kg/(m*s^2)

10.

... Continue reading "Fluid Mechanics Quiz" »

Estimating Visibility and Air Quality Impacts

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Q4) The most widely used equation for estimating visibility is the Koschmeider equation:

                              Lv = 1200 km x µg/m3 / particle concentration

Where Lv is the visual range, the distance at which an average person can barely distinguish a dark object (such as a mountain or skyscraper) against the sky. This equation is an approximation, based on an average set of atmospheric particles.

  • In the Grand Canyon and the surrounding area, on clear days, one can easily see mountains 120 miles away. What is the probable concentration of particles in the atmosphere when one can see that far?
  • If the particle concentration in the atmosphere is increased by 1.5 µg/m3, what is the percentage decrease in the visual
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Verb Alternations: Body-Part, Causative, and Dative Shifts

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Verb Alternations in English

The body-part possessor ascension alternation is characterized by a change in the expression of a possessed body part. The possessed body part may be expressed as the direct object of the verb (e.g., Margaret cut Bill’s arm), or the possessor may be expressed as the object of the verb with the possessed body part expressed in a prepositional phrase (e.g., Margaret cut Bill on the arm).

Examples:

  • NPagent Verb [NP’s body-part]theme: Margaret cut [Bill’s arm].
  • B-p possessor ascension construction: NPagent Verb [NPtheme] [on the body-part]: Margaret cut [Bill] [on the arm].

The body-part possessor ascension requires a sub-event ACT that involves contact. Consequently, "break" verbs typically do not participate in this... Continue reading "Verb Alternations: Body-Part, Causative, and Dative Shifts" »

Understanding Morphemes: Simplex and Complex Words

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The morpheme is the smallest, indivisible unit of semantic content or grammatical function from which words are made. Words can be classified into monomorphemic or simplex words ('faith' or 'week') and polymorphemic or complex words ('faithfully' or 'weekly'). 'Faith' and 'week' are free morphemes, while 'faithfully' and 'weekly' are bound morphemes that need to be attached to others. Bound morphemes can be prefixes, suffixes, or infixes.

Free morphemes act as bases to which other morphemes are attached to form derivatives. 'Mother' and 'faith' are examples of simplex bases, while 'faithfulness' is an example of a complex base composed of multiple morphemes.

'Teeth' and 'tables' are examples of nouns in the plural form, with 'tables' showing... Continue reading "Understanding Morphemes: Simplex and Complex Words" »

Simple Machines: A Comprehensive Guide to Mechanical Advantage

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Simple Machines and Mechanical Advantage

Simple machines are devices that make work easier. They do this by changing the magnitude or direction of a force. Many simple machines are combined to create complex machines.

Wheel and Axle

A wheel is attached to a central axle so that when one turns, the other must turn. A longer motion at the wheel's edge is converted to a shorter, more powerful motion at the axle. Conversely, a short, powerful force at the axle moves the wheel's edge a greater distance.

Pulley System

A single pulley simply reverses the direction of a force. When two or more pulleys are connected together, they permit a heavy load to be lifted with less force. The trade-off is that the rope's end must move a greater distance than the... Continue reading "Simple Machines: A Comprehensive Guide to Mechanical Advantage" »

Introduction to Motion, Forces, and Momentum in Physics

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- Scalars and Vectors

Scalars require magnitude and unit (distance, time, speed, mass)

Vectors require magnitude, unit, AND direction (displacement, velocity, acceleration, force)

• Force vectors are drawn with their tails attached to the point of application on the object.

• 1D vectors use right/left, up/down, +/-

• 2D vectors described using angles, measured clockwise and anticlockwise from the vertical and horizontal

- Adding Vectors

• 1D vector: make one direction (up, right) a positive value and the opposite direction (down, left) a negative value, then add them all up.

• 2D vector: draw the first vector in the appropriate direction, then the second vector from the head of the first. Then use a2 + b2 = c2 to find the hypotenuse... Continue reading "Introduction to Motion, Forces, and Momentum in Physics" »