Can the Time weighted average (TWA) exposure concentration be estimated starting from the Short-Term Exposure Limit (STEL)?

Hello, I have got an MSDS indicating the STEL of a compound and I'd like to know what the relevant TWA would be. Is there a general ratio which roughly links the two parameters (regardless of the...

31 December 2019 4,439 4 View

Could anybody provide a reference on the X-ray diffraction pattern of silicon?

Hello, I am after a paper reporting the X-ray diffraction pattern of silicon, possibly including all the diffraction peak positions. Thanks, Antonio

09 October 2019 9,644 4 View

How is water activity of pharmaceutical products measured?

Hello All, Which methodology should I follow to measure water activity of pharmaceutical materials? I am aware that there are two USP procedures in this regard, chapter 922 and 1112. Which of...

04 May 2019 4,158 5 View

How can I calculate the time per step if scan range, scan speed and step size are known?

Hello All, I am trying to reproduce an XRD method. I know scan range, scan speed and step size. How do I work out the time per step? Thanks, Antonio

05 June 2018 225 8 View

Could anybody suggest any (possibly pharmaceutical) material which could be used for PXRD proficiency testing?

I would like to fin out more information about which type of material (ideally pharmaceutical compounds) could be suitable to perform both qualitative and quantitative Powder X-ray diffraction...

31 December 2017 2,559 10 View

Could anybody suggest how to calculate the heat of adsorption/desorption from heat flow data (DSC) in mW?

Hi, I have got some DSC data related to the heat flow in mW (milliWatt I presume?) measured during adsorption/desorption of CO2 onto/from an activated carbon. I'm getting some inconsistent...

05 June 2015 3,006 5 View

Could anybody advise about the demineralization procedure of activated carbons?

01 February 2015 9,201 4 View

Could anyone recommend any companies in UK to purchase activated carbons from?

I'd need to purchase some activated carbons. Ideally, I would need two different type of products, a carbon having high micropore volume (d

06 July 2014 2,299 2 View

Has anybody been to any previous editions of the EUEC (Energy, Utility & Environment Conference)?

I'm planning to go to this year's edition in San Diego. It looks like a big event. My project is about CO2 capture so it kind of fits quite well in there. However, it would be nice to get some...

06 July 2014 2,669 1 View

What is the best technique for investigating the presence of CaO in a solid sample?

I've seen from the literature that XRF gives results in terms of oxides (e.g. CaO). Is this correct? What's the difference in terms of chemical composition results between XRF, XRD and EDX?

05 June 2014 716 15 View

Does the pressure(-600 mmHg) affects pH?

When I conducted the degassing experiment using decompression under anaerobic condition(and I used ferrous based chelating agent), the oxidized ferric were observerd. So, could you tell me the...

03 March 2021 4,892 5 View

Why can't make aluminum nitride film successfully by use sputter?

We use reactive sputtering process to make aluminum nitride film, and want to make c-axis aluminum nitride film on a silicon substrate, but the crystal orientation cannot be seen with...

03 March 2021 7,975 3 View

Is there any test to determine the cardiovascular risk of patients with obesity? from the perspective of obesity?

We found tests to determine cardiovascular risk taking into account lipid profile, blood pressure, age, history of diabetes, other laboratories. But when weight is involved, there is a paradox. I...

02 March 2021 6,036 1 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

Why almost every element would be metallized in sufficiently high pressure and low temperature?

(This statement is from wikipedia, BTW). What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star...

02 March 2021 3,309 2 View

Sutter electrode holder leaking after applying positive pressure. How to fix?

I am using a Sutter electrode holder for my patch clamp experiments, but I'm having trouble keeping positive pressure inside my electrode due to a leak out of the back of the holder. I have added...

02 March 2021 5,829 1 View

What SPSS analysis should I run with one IV (with two levels) and two DVs?

Hi, I am trying to figure out which test would be most appropriate to run for the following question: Is there a difference in task blood pressure between smokers and non-smokers? There are two...

01 March 2021 8,235 2 View

How can we obtain a modification factor for creep parameters?

I want to obtain standard creep parameters of salt rock by creep parameters of rectangular samples. Is there a modification factor to convert creep parameters of rectangular (prismatic) rock salt...

01 March 2021 7,131 1 View

How much pressure we can reduce at the outlet to avoid Reverse Flow?

I am simulating Heat Exchanger. I have tried and tested all the methods to resolve this issue from the internet like refining mesh, improving skewness and orthogonal quality ,extending outlet to...

01 March 2021 6,985 3 View

How to separate water from glycerol solvent in a solvent recovery vacuum distillation column?

I am currently doing my third year design project. I have been assigned to design a glycerol recovery column in vinyl acetate monomer production. The process unit before the recovery column is an...

01 March 2021 9,525 4 View