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

Guidelines for survey (question type) analysis?

Hi. Please tell me what guidelines should i need to follow for questionaries' type research work in India. It is not hospital based work, we are conduction basic institutional based qualitative...

03 March 2021 2,037 3 View

Resistor definition in Piezoelectric bimorph with ANSYS workbench

Hello, good day! I am trying to simulate similar bimorph piezoelectric harvester with below commands. However, the output power doesn't change with resistor value. Please help to find the reason. ET,10,CIRCU94,0 !SET UP RESISTOR R,1,100000 !RESISTANCE VALUE TYPE,10 !SET ELEMENT TYPE E,1,2 !CREATE RESISTOR BETWEEN NODES 1 AND 2 Thanks in advance Regards,

02 March 2021 0 0 View

I need to image mesoporous silica nanoparticles that are in ~100 nm size and do high resolution TEM to look at mesopores. what grids should I use?

Need to image mesoporous silica nanoparticles using the TEM. Also, need high resolution TEM images to see the mesoporous structure. Kindly suggest what kind of grids to use. Thanks, Shatadru

02 March 2021 1,787 2 View

How to access MSCI KLD Stats and Sustainalytics?

Hello all, I'm currently working on my undergraduate thesis and I'm having difficulties trying to access KLD Stats and Sustainalytics because my campus Airlangga University and apparently other...

02 March 2021 8,525 1 View

Ideas for Phd's Thesis on pricing (Marketing)?

Hi everyone, I'm studying Marketing and I would like to write my PhD thesis on the topic of pricing. Any specific ideas?

02 March 2021 9,706 5 View

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02 March 2021 3,060 3 View

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02 March 2021 932 1 View

How do I determine the degree of polymerization of PEG 400 based on NMR integration?

Hello, I am working on the photocatalytic degradation of PEG 400. I would like to know if it's possible to determine the degree on polymerization based on NMR integration, or by the MW of the...

02 March 2021 6,186 3 View

How to calculate BREQ 3 questionnaire?

how to calculate BEHAVIOURAL REGULATION IN EXERCISE QUESTIONNAIRE BREQ 3 ,which contain 24 questions and each question has 5 answers (0- Strongly disagree , 1-disagree, 2- Neither agree nor...

02 March 2021 811 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