Thermal Insulation

Thermos Flask

In cold places, we want hot coffee or hot tea, hot food.

We design for reducing heat flow, e.g. heat exchanger, building insulation, thermos flask and so on. Thermal insulation materials must have low thermal conductivity. This is achieved by trapping air or some other gas inside small cavities in a solid. Low conductivity of gas to inhibit heat flow. Heat can ,however, be transferred by natural convection inside the gas pockets and by radiation between the solid enclosure walls.

Apparent thermal conductivity of an insulating material accounting for conduction through solid material, and convection through the air space as well as radiation.

There are essentially three types of insulation materials :

1. Fibrous

Fibrous materials consist of small diameter particles or filaments of low density that can be poured into a gap as “loose-fill” or formed into blankets. Fibrous materials have high porosity.

  • Mineral wool for temperature below 700°C
  • Fiberglass for temperature below 200°C
  • Refractory fibers such as Alumina or Silica for temperature between (700°C to 1700°C)

2. Cellular

Cellular insulation are closed or open cell materials that are usually in the form of flexibile or rigid boards. Low density or low heat capacity and good compressive strength are their advantages. E. g.

  • Polyurethane
  • Expanded polystyrene foam.

3. Granular

Granular insulation consist of small particles of inorganic materials bonded into desired shapes or used as powder. E. g.

  • Perlite powder
  • Diatomaceous Silica
  • Vermiculite
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3D Generative Advanced Manufacturing Process

3D Model

It’s possible to build objects directly in three-dimensional space. Direct three-dimensional techniques are three types

  • Shape generation through point by point
  • Shape generation through surface by surface
  • Shape generation through simultaneous creation of whole object.

Beam Interference Solidification (BIS)

This method was patented by Formiographic Engine.

In this process, using material is a photosensitive transparent liquid plastic (Monomer).

When monomer subjected to a laser beam of a particular frequency, it reaches a reversible metastable state and no bonding reaction takes place. But when a part of liquid that is already in a metastable state is hit by another laser beam of a specific frequency, polymerisation of metastable state takes place, resulting in the solidification of voxel (Volume Picture Cell) at the intersection of the two beams. By moving the two laser guns in a particular way, the volume of the desired object can be generated voxel by voxel.

Ballistic Particle Manufacturing (BPM)

Pyramid

This process undergoes layer-by-layer application.

In the direct three-dimensional approach, the part building is achieved by shooting of molten droplets on top of each other. The two piezoelectric inkjet printing nozzles are guided by manipulators to deposit the molten droplets according to need from any direction instead of using an array of such inkjet nozzles as done in the layer-by-layer approach.

Six axis robots can be used for the purpose. One of important advantage of this approach is the elimination of support structures.

Direct Metal Deposition (DMD)

Machine

The University of Michigan, Ann Arbor, has commercialized a laser machine for generating three-dimensional metallic parts.

Metal powder is supplied which is melted by a high power laser beam and functional metal part can be generated. The deposit head is guided by a manipulator.

Holographic Interference Solidification (HIS)

Drawing

A three-dimensional image is projected in a vat containing a photosensitive liquid monomer and a whole three-dimensional surface gets solidified as a whole.

The holographic film for projecting the image is created with a CAD system. A system based on this principle has been developed by Quadtec Pry., Melbourne.

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The Study Of Transfer

The transfer of Momentum, Energy, Mass, Electricity.

Heat transfer

Recognized as a unified discipline of fundamental on basis of Fluxes, Forces.

A flux like – Heat Transfer, Momentum Transfer, Mass Transfer, Electricity and Chemical Reaction rate is directly proportional to respective conjugate force of

  1. Heat Transfer
    • Temperature Gradient
  2. Momentum Transfer
    • Velocity Gradient
  3. Mass Transfer
    • Concentration Gradient
  4. Electricity
    • Electric Potential Gradient
  5. Chemical Reaction
    • Chemical Affinity

The constant of proportionality being a property of medium, like Thermal Conductivity, Viscosity, Diffusion Co-efficient and Electric Conductivity.

A driving force causes the respective flux from a higher to a lower potential and reverse never happens spontaneously.

It’s law of nature
Nature

Transfer process indicates

The tendency of a system to proceed towards Equilibrium

For example In a solid body Non-uniform temperature distribution is transferred so establish a Uniform temperature distribution in the body

  • Thermal Insulation
    In cold places, we want hot coffee or hot tea, hot food. We design for reducing heat flow, e.g. heat exchanger, building insulation, thermos flask and so on. Thermal insulation materials must have low thermal conductivity. This is achieved by trapping air or some other gas inside small cavities in a solid. Low conductivity of gas to inhibit … Continue reading Thermal Insulation
  • 3D Generative Advanced Manufacturing Process
    It’s possible to build objects directly in three-dimensional space. Direct three-dimensional techniques are three types Shape generation through point by point Shape generation through surface by surface Shape generation through simultaneous creation of whole object. Beam Interference Solidification (BIS) This method was patented by Formiographic Engine. In this process, using material is a photosensitive transparent liquid plastic (Monomer). … Continue reading 3D Generative Advanced Manufacturing Process
  • The Study Of Transfer
    The transfer of Momentum, Energy, Mass, Electricity. Recognized as a unified discipline of fundamental on basis of Fluxes, Forces. A flux like – Heat Transfer, Momentum Transfer, Mass Transfer, Electricity and Chemical Reaction rate is directly proportional to respective conjugate force of Heat Transfer Temperature Gradient Momentum Transfer Velocity Gradient Mass Transfer Concentration Gradient Electricity Electric Potential Gradient … Continue reading The Study Of Transfer
  • Viscosity
    Viscosity is defined as the property of fluid which offers resistance to the movement of one layer of fluid over another adjacent layer of the fluid. When two layers of a fluid, apart by a distance ‘dy’ , move one over the other at different velocities, say u and u+du as shown in figure, the viscosity together with … Continue reading Viscosity
  • How to know the mass without weighing?
    Hello friends, Let’s talk about the mass of any material. You want to know about it, by using a formula… Using three easy steps That’s helpful for you… For Mass calculation without weighing any material. Let’s supposed I give you a sheet of steel and without weighing machine, tell me the mass of sheet. OK dear friend, yes … Continue reading How to know the mass without weighing?

Viscosity

Viscosity is defined as the property of fluid which offers resistance to the movement of one layer of fluid over another adjacent layer of the fluid.

Fluid

When two layers of a fluid, apart by a distance ‘dy’ , move one over the other at different velocities, say u and u+du as shown in figure, the viscosity together with relative velocity cause a shear stress acting between the fluid layers.

Figure

The top layer causes a shear stress on the adjacent lower layer while the lower layer causes a shear stress on the adjacent top layer. This shear stress is proportional to the rate of change of velocity with respect to y. It is denoted by τ (Tau)

Mathematically, τ ∝ (du/dy) or τ = μ (du/dy) where μ (mu) is the constant of proportionality and is known as the co-efficient of dynamic viscosity or only viscosity. (du/dy) represents the rate of shear strain or rate of shear deformation or velocity gradient.

We have, μ=[τ/(du/dy)]

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How to know the mass without weighing?

Calculation

Hello friends,

Let’s talk about the mass of any material.

You want to know about it, by using a formula…

Using three easy steps

That’s helpful for you…

For Mass calculation without weighing any material.

Let’s supposed I give you a sheet of steel and without weighing machine, tell me the mass of sheet.

OK dear friend, yes you can tell

By using a formula

(Mass =Volume x Density )

Volume of Sheet

First of all measures the dimensions in Meter.

Height, Length and Width

For e. g. Height (0.002 m) , Length (1.2 m) and Width (2.5 m)

Volume of sheet=0.002×1.2×2.5 m³ =0.006 m³

Density of steel

Mechanical property

Density of steel in Kg/m³

Generally steel density for calculation 7860 Kg/m³

Mass Calculation

Mass of steel sheet =volume x density =0.006 x 7860 =47.16 Kg