Selecting particular columns from large datasets (csv) using R Studio?

So I have large number of csv files (100+) in a directory with same structure and column names. The data is in time series and there are approx 30 columns/file. However i only want to aggregate...

08 February 2021 245 5 View

How much pre-PCR dilution of mixed-template DNA extracted from pollen (honey) is appropriate for Metabarcoding?

I'm working on pollen DNA metabarcoding to identify the floral composition of honey. How much pre-PCR dilution of mixed-template DNA extracted from pollen (honey) is appropriate for the...

28 December 2020 9,132 1 View

How to add two vertical and parallel Fresnel reflection coefficients to retrieve overall reflection coefficient for a right hand circular wave?

I have a problem in which a right hand circular polarized wave (GPS wave) encounters an ideal smooth plane obliquely, and then is reflected off that. To solve this kind of problems, the wave is...

28 December 2020 2,271 3 View

Which is better to focus on teaching or research for a good academic life and Why?

Which is better to focus on teaching or research for For a good academic life and Why?

26 December 2020 5,737 9 View

Is ag paste suitable for back contact on silicon wafer? or i should deposit al on the back surface using pvd or plasma sputtering?

Fabricating silicon solar cell

22 December 2020 4,906 7 View

Which renewable source is the best ?

wind hydro solar etc.

21 December 2020 6,360 16 View

Why is light pure energy?

light is pure because the light is the simplest electromagnetic construct but the energy of any object is also of the same kind.

20 December 2020 207 4 View

How to handle Missing Values for Skipped Questions (Systematic Missing) in R ?

10 December 2020 435 4 View

What is the best industrial emulsifier to make silicon oil in water emulsion?

I need to make long-lasting stable emulsions of 6 wt. % percent silicon oil in DI water. The previousely made emulsions using Tween and Span Emulsifiers did not remain stable after a week.

31 October 2020 3,568 3 View

Carbon Emission calculation factors ?

I am thinking about writing a paper on carbon emissions based on electricity consumption data from some buildings. From a research perspective, which factors should i specially focus while...

09 October 2020 4,142 3 View

What is Nano technology with coronavirus helpe the human..and is it nano mterals removal of covid19?

I anwar by adsorption or reaction ..but it is either more method...

02 March 2021 4,811 2 View

How to compare different concentrations of nanoparticles for characterization from ICP-MS?

I took measurements of different concentrations of 15 nm and 5 nm Au nano particle solutions. I'm trying to determine which concentration I measured gives the best reading overall. I also...

02 March 2021 7,626 1 View

How to model the battery pack in PSIM or PSCAD?

Hello, I have simulated a single battery cell using Thevenin equivalent circuit. For a battery pack, I have a large number of cells connected in series and parallel connections. Is there any way...

28 February 2021 2,116 1 View

How to find the right number of integration points in second order 3d finite elements?

I am familiar with finite element simulations and numerical schemes like the Gauss Legendre quadrature. I also know that the Gauss integration yields exact values for polynomials up to degree 2n-1...

27 February 2021 6,818 3 View

High aspect ratio hexahedral mesh optimization solver?

I am interested in evaluating mesh optimization solvers that converge to high aspect ratio unstructured hexahedral grids. In other words, I am interested in a solver that optimizes warpage,...

26 February 2021 7,279 2 View

LEDs on Vis Light photo degradation of MB water sol via N doped TiO2 in a mini flume?

Good day to all, I have no experience with light emitting diodes. I am building a glass mini flume to demonstrate the photo degradation of Methylene Blue in water running over self cleaning...

26 February 2021 4,026 5 View

Zno nano particles colour changed from white to grey in process of calcination any suggestions?

In the formation of Zno nano particles process, after drying at 120 degree C, my zno nano particles are completely white but when i calcine it for 450 degree C it converts into grey colour. i...

26 February 2021 2,435 4 View

What is the best solvent to remove PDMS from nano particles?

I want to remove PDMS oligomers from the surface of nanolayers. I have just read a very helpful paper about the compatibility of PDMS with different solvents( Solvent Compatibility of...

24 February 2021 7,845 5 View

Anyone with some Transgenomic Wavemaker software? Seeking help from the chromatography community?

I am trying to seek out some Transgenomic Wavemaker software (happy to purchase a computer too) to operate a fraction collector. The only way to connect to the fraction collector so far is to...

23 February 2021 9,181 1 View

How to validate regridding results of environemental data to higher spatial resolution in R?

I am working with several continous, environmental marine datasets at varying original spatial resolutions. My aim is to regrid each dataset to one common, high resolution grid. I am currently...

22 February 2021 2,290 2 View