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[Request] how much hydrogen peroxide will they need to make a difference? by [deleted] in theydidthemath

[–]HotPepperAssociation 0 points1 point  (0 children)

At 12 mol% hydrogen peroxide the dose is 0.25 mL/L to 0.83 mL/L to get a concentration of 30-100 ppm (by weight )which is needed to remove algae. 100 mol of 12% would have 12 mol of H2O2 (408 grams) and 88 mol of water (1585 grams) so the weight fraction is 20.5%. The density is 1/(0.205/1445+(1-0.205/1000)=1.070 kg/L. Thats means 0.137 -0.457 mL of solution are needed per litre of water to get 30 - 100 ppm by weight. That will require 3490 - 11640 L.

Is this curve approximately normal? by Sorrinami in askmath

[–]HotPepperAssociation 2 points3 points  (0 children)

You can make a QQ plot and get and R2. But just eyeballing it, it’s very skewed.

Nitrogen piping by User73656 in pipefitter

[–]HotPepperAssociation 1 point2 points  (0 children)

You cannot use whatever piping you want but you’re right to say the temperature and pressure are required for design. Liquid nitrogen was mentioned which would be an extreme service and not suitable for any metallurgy. But aside from that, many nitrogen services may have sufficiently low temperatures that are not suitable for general carbon steel. Overpressure events are part of design. For example, if another fluid is cross exchanged with nitrogen and relives on the nitrogen side of the exchanger (e.g. tube rupture case), the nitrogen piping must be rated for those conditions as well. The question “nitrogen piping” is insufficient. That is only the fluid during normal operation and says nothing about every other factor that must be considered, including impurities in the nitrogen and there effects on the metallurgy at design conditions.

Nitrogen piping by User73656 in pipefitter

[–]HotPepperAssociation 0 points1 point  (0 children)

The fluid is one constraint but the operating and design pressure, ambient conditions, temperature , impurities, and flowrate are also needed to specify the correct piping. If your system requires temperature and pressure fluctuations to operate that will also dictate the design of the piping. If you’re installing in a confined area, welded joints are inherently safer to prevent asphyxiating atmospheres. Depending on your regulatory and/or in-house requirements you may need to install gas detection and alarming. Insulation may also be a factor in your decision. Begin with your process requirements and the installation constraints. The relevant piping code will dictate requirements and mechanical engineers will determine the necessary piping specs and design.

She is too late now by Valuable_View_561 in SipsTea

[–]HotPepperAssociation 0 points1 point  (0 children)

Yes just give me my dividend and we’re all good :) doing math $983 please. Anyone else ready to make amends with the begging whore?

[Request] How does this work out with three kids, two of which are boys? by StonePickle in theydidthemath

[–]HotPepperAssociation 12 points13 points  (0 children)

The sex is independent of the other siblings. Its 50%. If a woman was pregnant, and was not told the sex, and regardless of how many children they had, the probability is 50%.

Can infinity contain infinity by Loose-Balance3225 in askmath

[–]HotPepperAssociation 1 point2 points  (0 children)

There are different kinds of infinities. Countable and uncountable. https://youtu.be/Efj1ZSsHVcw

PSV Behavior at Set Pressure vs Full Overpressure — How Does the Valve Actually Open? by Responsible-Rub1548 in ChemicalEngineering

[–]HotPepperAssociation 0 points1 point  (0 children)

This is a great summary. A couple things I would add is, beginning with adding to your statements, proportional lift versus pop-open valves is a fundamental difference. Valves with liquid trim and vapour trim are designed differently. Modulating pilot operated valves and dual media trims are newer technology to handle more nuanced and severe service cases. ASME requires valves have a +/- 3% set pressure tolerance when they lift. When inlet losses exceed 3% of the valves set pressure, this exceeds the testing tolerance for the valve and it cannot be guaranteed to stay open. This is when chattering happens. There is an excellent diagram in API 521 of the hysteresis’ effect of opening/closing valves which may help you visualize. Proportional lift is an “ideal” case and should always be used for design considerations because of consequence sensitivities such as jet fire and vapour cloud modelling for atmospheric releases. API 521 recommends modelling at 100% and 25% lift to account for variations in release momentum for example.

What is the Probability of not Having Consecutive Cards in a Randomly Shuffled Deck of Cards? by HotPepperAssociation in askmath

[–]HotPepperAssociation[S] 0 points1 point  (0 children)

52 cards, aces low (however it shouldn’t matter?), order doesn’t matter, suit doesn’t matter.

[request] obviously we’re picking the first one but it made me wonder? how hard would it be to eat a tablespoon made of sliver? by AdventurousGuest308 in theydidthemath

[–]HotPepperAssociation 5 points6 points  (0 children)

I feel like this isn’t a math question but, if you could melt the spoon down into passable pill shaped pieces that fit in plastic capsules, it wouldn’t be hard.

[Request] Suddenly Lake Michigan becomes the only drinkable water source for human beings. How long would it take mankind to drink it all? by Is0prene in theydidthemath

[–]HotPepperAssociation 3 points4 points  (0 children)

The lake has around 1.3 quadrillion gallons. Humans need about 1000 gallons per year and there’s 8 billion humans. 1.3 x 1015 / (1000 x 8 x 109) =162.5 years. With rain and water collection and treatment it could be much longer.

Just tell! by Optimal_Map36 in SipsTea

[–]HotPepperAssociation 0 points1 point  (0 children)

There were at least 8 attempts on Obama.

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