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

Can anybody suggest safest irreversible inhibitor for cholinesterase (EC:3.1.1.7)?

I am working on the assay of brain acetylcholine. I need an irreversible inhibitor of cholinesterase that is relatively safer (not volatile, preferably solid) to use. This is to prevent the...

08 December 2020 3,797 3 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

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 4 View

Can water be extracted from Olivine?

I have always been interested in geology and wondered about how unique structures of materials behave in different circumstances. I stumbled upon Olivine, the magnesium iron silicate, and heard...

28 February 2021 7,330 4 View

How does charge on working electrode changes with rising potential?

During performing CV of a GCE or modified GCE, we rise the potential in the first half of the cycle and reduce it in reverse half. During the first half, what is the nature of charge on GCE or...

25 February 2021 7,994 3 View

What is the detection limit of ED-XRF technique for transition metals in silicon ?

Hi everybody, please, can someone tell us if the transition metals (W, Fe, Ni, etc ...) in silicon destined for solar cell manufacturing can be detected by ED-XRF technique. Note that the...

18 February 2021 6,231 4 View

Passivation of chromium cast Iron in high temperature?

14 February 2021 2,157 3 View

Why ICP-MS test for Teflon filters that collected PM2.5, show really high results in the millions of ug/g ?

I analyzed soil and ash samples using ICP-MS for 28 metals, then I resuspended those samples to collect PM2.5 particles in a filter using a selective inlet inlet. My only issue that Fe and Al...

13 February 2021 7,592 3 View

How to interpret different leached phases of metapelites?

Extraction of three different phases of metapelites, mostly phyllites as the Carbonate phase, Fe-Mn Phase, and Silicate phase has been obtained. After doing ICPMS, different results have evolved....

11 February 2021 5,198 10 View

How can I take subsamples of water from a larger sample in a way that allows me to measure the iron content of the subsample?

I learned how to take subsamples with a magnetic stir bar, but I noticed iron particles stick to the bar, and I am having trouble finding a standard method to solve that problem. How can I take a...

04 February 2021 4,778 1 View

Sample preparation for ceramics i.e. iron silicate (fayalite), iron oxides, alumina, spinel mineral (hercynite)?

Recommendations in preparing ceramics for nanoindentation and in the process minimize introducing stresses from sample preparation i.e. polishing stage.

02 February 2021 6,211 3 View

What are effective methods for removal of iron from organic acids?

I am seeking methods to remove trace iron from organic acids, including acetic acid, propionic acid, and formic acid. Distillation works, but is expensive. I'm looking for alternatives to...

31 January 2021 984 3 View