Can randomization be done after we get our data?

Let's say that we are doing an online survey among a group of people with the same profession - cross-sectional study. The population size identified, and sample size calculation is done. And...

26 August 2020 3,511 5 View

Hi. Anyone have come across this issue where the baseline is shifted like this when running the hplc? Is it due to contamination or else?

Mobile phase used is 5mM sulphuric acid , type of column is Bio-Rad Aminex

09 July 2020 9,321 7 View

Hi. Do you have any idea why the peak looks like that as I guess this is the solvent peak produced?

I have run the levulinic acid standard through hplc-refractive index detector with column and detector temp at 63 and 50 degree respectively. Mobile phase used is 0.005 M H2SO4 at flow rate 0.6...

12 November 2019 6,348 2 View

Can waterbased acrylic emulsion cause corrosion?

I've purchased a waterbased acrylic emulsion to be used on metal. However, after applying this coating on my carbon steel, the steel corrode immediately. I've been doing some reading and...

21 October 2019 4,790 3 View

Do we need to add alcohol (ex: ethanol) if we used acid catalyst in sol-gel method?

Currently, i'm preparing my nanosilica via sol-gel method, but the nanoparticle's size obtained is >100nm. I'm using TEOS as a precursor, acetic acid as catalyst and water as hydrolyzing agent....

02 October 2018 9,901 8 View

What is the best way to reduce the motility of Rotifer?

26 August 2016 7,679 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

Is there a deep reason for using the squared modulus of the wave function as the probability density of the existence of the particle?

I think we were all surprised at the first time we got to know quantum mechanics that the squared modulus of the wave function is the probability density of the existence of the particle? The role...

28 February 2021 6,282 9 View

Why initial concentration of Pb not the same as calculated one when testing using AAS?

I am currently doing research on the adsorption of heavy metal using magnetic reduce graphene oxide. I use AAS to determine the concentration of the heavy metal. I prepare the Pb solution with...

26 February 2021 9,580 4 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 this the write procedure for acid digestion of soil for heavy metal analysis using AAS?

How to do acid digestion of soil sample with 3:1 aquaregia in an open vessel?

23 February 2021 3,053 7 View

Is there a suitable way to confine cell attachment area inside a multi-well plate?

Are there any types of cylindrical cell culture inserts that are designed to confine cell seeding area? Say, if I'm using a 12 well plate (3.5 cm^2/well), but only want to seed cells in the middle...

22 February 2021 7,127 4 View

How can I simulate the optical absorption spectrum of a biomaterial (like DNA or protein) in COMSOL?

I need to simulate the optical properties of a biomaterial, namely DNA, in COMSOL. Basically I need to simulate the IR absorption spectrum of a cylinder filled with a 'concentration' of DNA. I am...

21 February 2021 3,043 3 View

Hi..how to isolate crude HDL (all subfractions) from human serum by size exclusion chromatography?

I would like to know about isolation of crude HDL from serum by SEC. Is it possible to perform with a serum sample volume of

19 February 2021 5,576 2 View

How to calculate the Atomic Polar Tensor using DFT ?

Dear friends, I am a beginner at DFT calculation. I have done a structure optimization using DFT- B3LYP/6-31G*, Nevertheless, I don't know How to calculate the Atomic Polar Tensor (APT) in...

17 February 2021 9,082 3 View

Unusually Busy Raman Background?

Hello, I am observing a nearly periodic background spectrum for a wide variety of SERS substrates. I see this response (attached below) for bare Au films, Cu films, and Au nanoparticles on...

15 February 2021 9,922 5 View