SciELO Electronic Library

SciELO is a very good library of scientific publications, mostly from researchers in South American countries. It has articles in Spanish, Portuguese and English, and also has search engine interfaces in each of those languages. I’ve found it an excellent alternative resource for finding articles that do not show up in the customary search engines such as provided by my university’s libary catalogue. It contains about half a million articles.

The SciELO search engine is quite flexible. For instance, if one wants to find articles in Spanish or English, about diode (juntura) models which use the Lambert W function, one can use this search term: ((diode) OR (juntura)) AND (Lambert)

Here is a link to the English language search interface:
http://www.scielo.org/php/index.php

And a link to a Wikipedia article with some background about the project:
http://en.wikipedia.org/wiki/SciELO

And, so we have a nice picture to head up this post, here is the SciELO logo (of course, copyright owned by them):

I like the pun in their name!

Best wishes,
Ken Roberts
31-July-2015

Disable Apps to Improve Performance

For several months now, I’ve been doing some fairly heavy duty calculations, finding roots of polynomials.  I got a new laptop, just for that purpose — it sits at home and crunches numbers.

One of the amusing things about it, is that it has a lazy operating system (Windows 8.1).    As the laptop crunches along, running three copies of the calculation software in parallel, from time to time the operating system offers helpfully that it can disable some apps (= applications) to improve performance.

It’s a classic instance of narrow-mindedness on the part of the operating system development team.  For them, performance is measured by the amount of unused capacity in the system.  it apparently does not occur to them, at a top-of-mind operational level anyway, that performance for the user (me) might consist in getting useful work completed.

Another recent activity has been to watch some episodes of Mr. Selfridge, about the founder of the London department store, Harry Gordon Selfridge, and to read the predecessor book upon which the TV soap is based.  What made HGS so successful was an unwavering commitment to service to the customer.  He would figure out what the customer wanted (even if the customer did not herself or himself know, ie articulate that need), and provide it — for instance, a place to have tea in the store, or to relax, etc.  HGS was the originator of the slogan “The customer is always right.”

I doubt that HGS would consider that his customers should disable their activities and commitments in order to “improve performance” in their shopping!

Best wishes,

Ken R.

24-Oct-2014

Espresso Problem Solved

Some time ago — in a post on 20-Dec-2013 — I mentioned trouble with a custom ground coffee, from a specialty coffee shop, clogging the espresso machine. I speculated that the difficulty arose from the custom ground coffee having been ground too finely. I’m pleased that the problem with using the specialty store’s coffee has been resolved, and can report my technique for using it. My speculation regarding grind size is not validated however. So, although I have a solution to the problem, how to enjoy the specialty store’s coffee, my hypothesis about grind particle size is not substantiated by what I’ve observed through the microscope.

First, the method: how to use a coffee grind that clogs the machine. The solution is like what one does with gravel to get good drainage. First put down a layer of coarse gravel — store-bought espresso ground coffee, which does not clog the machine. Then put down a layer of the finer gravel — the specialty store’s coffee. Since my espresso making usually involves coffee for two, that means two scoops, and everything works out easily: one scoop from the standard espresso, tamp it a bit, then the second scoop from the specialty espresso, and tamp a bit further, and then brew. It is excellent to be able to use this great-tasting specialty espresso in my machine.

Now, some microphotographs of the specialty coffee, and of three different standard espresso grinds. These are very crude, as I’m not a good microphotographer. Back lighting in each case. Each of the three standard espressos is a different brand of espresso from the grocery store.

The specialty coffee — the particles look a bit elongated:

And the three grocery store espresso coffees:

Each of the latter three appears to have particles which are uniform in width. So it may be that the difference is not the particle overall dimensions — related to the grinder setting — but rather to the specialty store’s grinder producing long thin particles. Those then could stick end-wise into the filter of the espresso machine.

Whatever. I’m just happy to be able to use the specialty store’s coffee, in a 50-50 mix with grocery coffee.

Best wishes,
Ken Roberts
19-Apr-2014