Recent content by rayj

Text books are great. Older books provide a benchmark in time. This is not only in technology but in view point and methods. Consider reading papers - from a large variety of sources. There are many ways to look at a particle in a box and how boxes share walls. As mentioned above, today's...

When you taste 'normal' brewed coffee, do you find either a sour or a bitter taste? How about for the cold brew? If neither, how would you characterize the taste?

moriah In item 1), "both" is the adjective of the phrase "As solids". Solids reference the initial statement of composition "cafestol and kahweol" as being oils. Yes, healthline.com states that coffee is acidic. Consider the characteristics of acidic food items such as vinegar and lemons. Both...

At brewing temperatures, both are solids. They melt at 370F. While they may dissolve in oils, they also have hydroxyl groups (along with substantial polynuclear rings) which may provide some water solubility. As such, the paper vs. cloth filter media have some differential effects partially...

Here is a pair of presentations that roll the equations into simple pictures: https://www.relativity.li/en/epstein2/read/c0_en/c8_en which points to: http://www.physastromath.ch/uploads/myPdfs/Relativ/Relativ_06_en.pdf

sysprog, Thank you for holding fast. Methanol was not regulated in Italy until 1985 due to 20 deaths and dozens hospitalizations at that time. While methanol was a 'natural' product in making grappa, the levels were low. Methanol was added by some due to the masking affect of poorer quality...

sysprog, Thank you. Yes, you are correct. And I meant to spell methanol, not method. Traditionally, wine is fortified with other distillates. The US only allows wines to be fortified with distillates of fruits. But other countries allow some amount of methanol to be added (it is cheaper)...

Yes, all of these are toxic. For reference: Methanol is a single carbon with one -OH Ethanol is two carbons with on -OH n-Propanol is three carbons with one -OH at one end Isopropanol is three carbons with one -OH in the middle n-Butanol is 4 carbons with one -OH at one end Isobutanol is 4...

While Hamming's book is a great resource, if you are in a hurry, online resources may help: Google search for digital filter differentiation https://www.mathworks.com/help/signal/ug/take-derivatives-of-a-signal.html https://www.dsprelated.com/showarticle/35.php...

The OP ( @Gaussian97 ) presented a function for a symmetrical derivative calculation (central difference). This may be useful is some instances. As this is a computational activity, a key in implementing it is the resultant errors in the steps necessary to carry it out. Compare the original...

jedishrfu That was a great site with wonderful information. Yes, there is the possibility of obtaining code for calculations. My primary concern is to be able to perform the symbolic math.

This is a great discussion. It is often productive to address such question as a decision process. We have a lot of statistics of subsets of populations for responses to different pathogens along with confounding factors. Such questions may help lead us to making more valuable decisions on what...

I would like to exercise the formulations in the book. I have read Gravitation and many others but I need to do more exercises. I get very bogged down in writing out the symbols. Are there electronic solutions for writing and exercising these equations? I have used Mathcad to perform...