Is geopolymer concrete porous?

Did you investigated the porosity of geopolymer concrete (GPC) which seems to be obvious while observing its microstructure? What are the reasons of porosity in GPC? How can we reduce it by...

06 July 2017 1,877 4 View

Why does the wavelength of light change as it travels from one medium to another, but the frequency doesn't?

Although velocity is linked with the direct relation to the product of frequency and wavelength, so can we say that modification in wavelength is compensated in the value of velocity to keep the...

06 July 2017 564 3 View

What will be the effect of surface smoothness on the thermal contact resistance?

How will the results vary corresponding to the surface texture of the body in terms of thermal contact resistance?

05 June 2017 8,625 4 View

What is the effect of solar concentrator on the solar spectrum?

Does the solar spectrum vary by passing through the solar concentrator? Is it dependent on the concentrator material which may absorb short wavelength and transmit certain wavelength? Please share...

03 April 2017 6,712 1 View

Why hot surface is cooled in the hotter ambient through natural convection?

In an experiment, the surface temperature of concrete raised quite higher than the ambient during day time due to intense irradiance. At night, this temperature was dropped due to convective heat...

02 March 2017 524 4 View

Why surface temperatures of different materials vary when exposed to identical ambient conditions?

In an outdoor experiment, I observed variations in surface temperatures of different materials while all of them were exposed to same ambient conditions (solar irradiation, wind speed etc). Please...

05 June 2016 3,000 6 View

Can Grashof number or Rayleigh number be negative?

I am calculating transient natural heat convection and for certain time interval the value of Rayleigh number is coming negative due to high ambient temperature as compared to surface temperature...

02 March 2016 4,464 13 View

Why are the velocities so high in my Boussinesq approximation Fluent simulation?

Hello, I have a mechanism where air rises due to convective flows. In this simulation, nothing is driving the air except this. I understand that the Boussinesq approximation only works for small...

02 March 2021 4,910 3 View

Is There Any Feasible Method To Test Fluorescent Compounds Other Than Fluorescence Spectrometers ??

Is There Any Feasible Method To Test The Efficiency Of Fluorescent Compounds Other Than UV Spectrometers ? Suggestions Would Be Appreciated !

02 March 2021 5,785 3 View

Where can I find life cycle inventory or assessment of non woven materials?

Dear network, I am looking for the LCA or LCI or at least the energy balances of the non woven fabrics process for my master project, in specific for natural fibers, yet I have found...

02 March 2021 9,662 1 View

Where to find data on trees in tropical agroforestry?

Hi, I'm looking for data (mainly related to management: growth rate, canopy size, soil and climate preferences, etc.) about tropical trees used in tropical agroforestry. Have you ever heard about...

28 February 2021 7,356 8 View

What is Flat Lens Antenna?

28 February 2021 5,433 3 View

Can impedance of antenna be less than 50 ohms?

I am simulating helix antenna in hfss, right now, giving excitation with 50 ohms port. When I see the results of Z parameter (real). It shows lower than 50 ohms. Do not understand, if it can be...

27 February 2021 4,218 7 View

Why do the air flow results vary totally when adding scalar in CFD ?

Dear All, We are using Autodesk cfd to calculate the air flow in a single sided naturally ventilated room, where air flow depends only on buoyancy due to temperature difference between inside and...

25 February 2021 9,602 4 View

Is is possible to pole with corona poling pellets of the sample material instead of thin films?

As it is highly probable that pellets will have a higher degree of air gaps and voids than thin films, is it possible to pole the samples with corona poling nevertheless? Or is there the...

24 February 2021 1,349 1 View

Have you ever experiencing air vent trouble in fermentation process?

Dear all, My research group is currently working with a 12-litre fermenter. Somehow, if we do the fermentation for more than 20 hours, the process will be more prone to contamination. Our current...

23 February 2021 1,908 2 View

Help with assigning pressure boundary conditions in FLUENT on a large structure?

Hello, I created a very tall tower (>1000m) and applied pressure boundary conditions at the inlet (bottom) and outlet (top) that correspond to the pressure are their relative altitudes....

22 February 2021 9,972 4 View