12 more posts in this thread. [Missing image file: vanillin.png]
For those who've dealt with Vanillin + NaBH4 reaction:
So I've got the vanillin/ethanol and BH4/NaOH solutions mixed together, and will add HCl until it's acidic. Then I plan on ice bathing this to get a precipitate of the vanillyl alcohol.
Looking at some online procedures and a video, this is as far as they go, but one or two others take this precip and do a ethanol heating/evap process to it. So for those who have experience with this, is that really needed (or in other words, did you do that)?
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Hey, /sci/, I'm in a basic programming class for python, and I'm having trouble understanding the in-class assignment that was given today. Could anyone help me out? The problem is as follows:
A prime number is a number that is only evenly divisible by itself and 1. For example, the
number 5 is prime because it can only be evenly divided by 1 and 5. The number 6, however, is not prime because it can be divided evenly by 1, 2, 3, and 6.
Write a Boolean function named is_prime which takes an integer as an argument and
returns True if the argument is a prime number, or False otherwise. Use the function in a program that prompts the user to enter a number and then displays a message indicating whether the number is prime.
We're working in python 3.2
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I usually don't do this but I need help, I have no idea on how to do a problem like this. In return here is Star Wars. That's science right
Jasper Metals is considering installing a new molding machine which is expected to produce operating cash flows of $73,000 a year for 7 years. At the beginning of the project, inventory will decrease by $16,000, accounts receivables will increase by $21,000, and accounts payable will increase by $15,000. All net working capital will be recovered at the end of the project. The initial cost of the molding machine is $249,000. The equipment will be depreciated straight-line to a zero book value over the life of the project. The equipment will be salvaged at the end of the project creating a $48,000 aftertax cash flow. At the end of the project, net working capital will return to its normal level. What is the net present value of this project given a required return of 14.5 percent?
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What do you think of Helen's Fisher Types, it is mainly focused for dating/relationships:
Explorer: (more dopamine expression) -- risk-taking, curious, creative, impulsive, optimistic and energetic
Builder: (more serotonin expression) -- cautious but not fearful, calm, traditional, community-oriented, persistent and loyal
Director: (more testosterone expression) -- very analytical, decisive, tough-minded; they like to debate and can be aggressive
Negotiator: (more estrogen expression) -- broadminded imaginative, compassionate, intuitive, verbal, nurturing, altruistic and idealistic
Explorers attract Explorers, Builders other Builders and Directors attract Negotiators and vice versa.
Thought most people are a combinations of those 4, usually there is a primary and a secondary type combination that predicts most of behavior, e.g. Directer-builder or Negotiator-Director, etc.
Fisher is a PhD in Physical Anthropology: Human Evolution, Primatology, Human Sexual Behavior.
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Is there gravity underwater?
Today I was in my swimming pool and it occurred to me that when underwater, I'm effectively weightless. I can float freely, which seemingly goes against the theory of gravity. I can spin, twist and do nearly anything in suspended or slow motion. Thus, I believe that gravity does not exist underwater. Prove me wrong.
I also discovered you can get sunburned underwater. The cooling effect of the water means you don't feel the burn, though...
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Is my reasoning correct when describing partial derivatives at P for the function given by this set of level curves? Is there anything i'm missing?
fx, the partial with respect to x at p is negative because as f(x,P) increases, the values of x are decreasing.
fy, the partial with respect to y is increasing at point p because as f(P,y) increases y increases, so fy at P is positive
fxx, this higher order partial is decreasing at a decreasing rate since the lines are getting closer together as f(x,P) increases, so fxx at P negative.
fxy, this higher order partial is negative rate since the lines are getting closer together at a decreasing rate at as f(x,y) increases.
fyy, this higher order partial is increasing at a decreasing rate since the lines are getting closer together as f(P,x) increases, thus fyy at P is negative.