Posts by Chemist 2677 publicly visible posts • joined 24 Mar 2010
"Does it matter??? Why be so vain about a passport photo???"
It's not a question of vanity - it's not easy in any kind of poor light or bright light to actually see the photo well enough to identify the individual - kind of the purpose of a passport. UK passport applications give all sorts of instructions about the quality, size & background of image required and then turn out an inferior product. (Unless all border officials have their eyesight modified !)
"Plus also it takes a fairly massive dose of it to do any sort of damage,"
~20 tablets over a few hours or less will do it esp. with a lower weight person or one with an already damaged liver. As the original article mentioned "a huge handful of ibuprofen and acetaminophen” it also appears to depend on the size of hand. I'm sure, in fact, that it was a colourful phrase rather than a measure but with some common drugs it really is too easy sometimes to treat them as relatively harmless
"Paracetamol is only intended for short term pain relief. It says so on very packet I've seen"
No it's often used for chronic pain like that of osteoarthritis. OTC bottles of all sorts of drugs are required to tell users that they should only use them for short period.
Paracetamol is relatively safe at normal usage levels but recent studies have suggested that chronic use at higher than recommended levels whilst not acutely toxic can in time lead to liver damage.
"That's also some claim when Germany is in such tight electrical straits they've had to buy a sizable chunk of their electricity from France lately."
I've mentioned here before that a comprehensive analysis of Germany's electricity stats (2014) can be found at :
http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/data-nivc-/electricity-production-from-solar-and-wind-in-germany-2014.pdf
Page 6 ;- first 11 months of 2014 total generated electricity ~470 TWh
46% coal, 9% wind, 7% solar,
"None of which are actually functioning today"
AFAIK the replica of the Manchester 'Baby' is around and ran in 1998. I was taught physics by a chapvwho worked on the original and had a photo of himself, stripped to the waist, working in basement surrounded by racking
"As I see it, the good of systemd is that I can reboot in a small number of seconds, and the bad is that I seem to have to do it at least ten times as often, for something like a wash"
Using OpenSUSE I reboot hardly ever and only switch off when I'm traveling. Updates arrive regularly and systemd seems to restart any daemons that have been updated.
"f you consider the graphene not as a sheet of carbon, but two layers of hydrogen stabilised by a lattice of carbon + electron soup ( extremely simplified, of course)."
"To migrate to the silicon any copper atom would have to react with the H of the graphene first.."
Sorry I should have noticed this sooner but I've been busy today. I'm afraid you are under a misapprehension - graphene doesn't have any hydrogen attached to it - it's pure carbon sp2 hybridized. so planar like benzene but with all bonds carbon-carbon
"It would work that way if you consider the graphene not as a sheet of carbon, but two layers of hydrogen stabilised by a lattice of carbon + electron soup ( extremely simplified, of course)."
Not sure the point you are making - It's known that a monolayer of graphene is an impermeable barrier under normal conditions ( I have a feeling that protons can tunnel through ) So as I stated copper is not going to be able to diffuse into the silicon
"You have to have good math capability and know your subject but computers are only needed for research"
Not my area exactly but ...You know, presumably, that solutions of the wave equation for anything other than the hydrogen molecule that approximations methods have to be used - that means computers, for anything rather larger , it means BIG computers
"it's silly to take an attitude of refusing to look at new stuff because you're familiar with the old."
Yet time & time again we're told here that there is no point in companies moving to Linux/LibreOffice or whatever due to the users inability to adapt/learn ( even though the same users seem to have moved to Android/iPhone etc without any forcing)
"but I found that FORTRAN code actually ran faster than it's similarly written C equivalent."
I've mostly written my scientific software in C but one of the major points in favour of Fortran seems to be the masses of thoroughly debugged routines/libraries (including source) available for a vast range of topics
"I would guess that any temporal effect there might be on a photon when it zips past a 100,000ly galaxy..."
AFAIK photons don't experience time. It's all now for photons - emitted and absorbed at the same instant even if billions of light years separate emitter and absorber. Google it. Strange place this universe.
"swirl non-deterministically "
Whilst I agree with your sentiment AFAIK chaos (theory) is deterministic in that you can write the equations, however the system that the equations describe is so sensitive to initial conditions that it doesn't matter and appears to be random or pseudo-random very quickly
See animation : http://en.wikipedia.org/wiki/Chaos_theory
"it shows the DNS addresses at the bottom."
In many cases it will just point to the router . I usually embed my normal DNS server addresses in the nm settings for my access point.
At the moment I'm still looking for a reasonably simple explanation of how this exploit works and indeed how it is triggered.
"Often when I try to use multi-threaded code that has high memory usage the entire Linux OS will crash. "
Strange, even 10+ years ago using a dual xeon Dell workstation with the quite large memory of 2GB ( for the time) we ran multithreaded protein modelling software under RedHat for DAYS at ~100% CPU without any probs.
And now my 8GB 4(8) core i7 laptop (OpenSUSE13.1) running multithreaded software can render/convert video running at ~90% CPU without issue.
"What about Kdenlive (KDE non-linear video editor)?"
I've used it for years, since ~2012 I've used it for 1080/50p video and i find it excellent (esp. for free) - I've not used anything except Linux for years so I can't comment on Windows/Mac as hardware is now so much faster tthan when I used editors on Windows for SD video. I found kdenlive used to crash before ~2012 but that is now a thing of the past. I think it's one of the best for Linux and easier than Cinelerra to pickup.
I use inkscape for laying out PCB (all manually) but I find its line width and spacing accuracy first rate certainly SOIC, and even TQFP are possible just using laser toner to copper transfers.
Thanks for the clarification - I was misled by "most changes you make will be irreversible"
as clearly they are not. The process of altering a step out of a pipeline of changes that are eventually rendered is in fact what I'm used to with Darktable.
As I mention above I don't us Gimp much but have been grateful for the undo history on many occasions - although in any case, of course, I'd never overwrite an original image
Not sure what is meant by this - Gimp lets you role back for a considerable number of changes (Edit - Undo History ) That said I don't use it much except for the odd quick job.
That's 'cos I use Darktable which is awesome as you say and covers virtually all my photo needs. Especially good is its profiles for various DSLR cameras for RAW processing.
"you establish your own fixed IP so you can talk to your home remotely. And in either case, you're likely subject to any hacker with a backdoor into either, which are numerous."
There is another option I use when I'm feeling paranoid. I have a few PIC microcontrollers, run by a server program on my Linux fileserver. I've set up a system whereby a cron job regularly reads a text file on my website and sets-up the PICs accordingly. A futher cron job reads any inputs from the PICs and writes out to the website. This being a totally passive system means I don't have to ssh in to home just to change a few things.
"And the other 38% comes from"
Well if you can't be a***d to read the ref !
Nuclear, gas, biomass, hydro. ( I've got a German neighbour here in Switzerland and he often spouts off about how much cleaner German electricity production is " Mostly wind and solar" )
Greek bonds might well be biomass
"Of course you haven't noticed a change in behaviour in your distro, you already have that "feature""
As I've been using Linux from the mid-90s I'd notice especially as I run 6 machines + several VM. Only reboots for kernel updates - changes to the desktop environment occasionally request logout/in
Can we have some comments from other users about this
It's not just parallelisable applications but how many processes you want to run. I'm used to running many cpu-intensive programs at the same time whilst doing lots of other stuff whilst they get on with it.
"Outside rendering, are there many other widely used parallelisable applications?"
Plenty of scientific ones, but even for my usage when travelling I use scripts to further process sets of directories of jpgs(that's 100s of files in each, 5k*3k ) (scaling/sharpening) to produce sets that match the native resolution of various devices they are going to be viewed on. Having 4-8 copies of that code running can give a laptop a good work-out. I also do the same with video using ffmpeg to convert 1080/50p to 720p again for display purposes, and during this time I still want to write, email, upload, browse, and process RAW DSLR images, build panoramas etc. That's why I bought an i7 with 8GB. I could have done the rest with my old Celeron 1GB laptop ( I admit the screen hinge is glued with Araldite and possibly living on borrowed time), but when 1 minute of video needed 30 mins of rendering it was too slow.
"and portability requirement large."
I've tended to prefer desktops for speed, ease of fixing, custom building and upgrading but I travel a lot and processing (on the road) RAW photos and particularly 1080/50p video editing/rendering requires quite a lot of muscle. My preferred video editing software will wind all 8 cores up to ~85% utilisation during rendering
"You built your own laptop ? Impressive."
I too always build desktops - laptops are more of a problem but a number of smaller UK sellers now sell their ranges without OSs and charge extra for Windows. The 8GB i7 I'm writing this on is one such, nice 1920x080 display and OpenSUSE 13.1 installed without a glitch
"But you will probably find that programs written by chemists to solve chemical ...."
In science it's often the case. Trying to explain some arcane point with lots of caveats to a programmer without a serious grounding in the topic can be frustrating, and usually leads to a poor outcome. Not the programmer's fault of course just difficult to comunicate between the worlds.
Incidently whilst I agree that many scientists can be poor programmers two of the best coders I've every worked with were originally chemists.
The point is that the thermodynamics can never be better than ~300kJ/mole. And that might be at low throughput - that energy has to be supplied one way or another. Now has this catayst made significnt progress towards this ? i.e. allowing higher throughput whilst reducing the overpotential.
(Being able to reduce the cell voltage somewhat may be benificial but the waste heat thus generated will lower the electrical energy needed for the reaction. To reach ~100% efficiency the cell voltage needs to be reduced to ~~1.5v (at realistic throughputs .which is the issue as always with thermodynamics)
Catalysts, as I'm sure you know, increase the rate of reactions but don't alter the thermodynamics. I'm not sure how this catalyst is supposed to reduce the power required unless there's some ability to run at lower effective electrode voltage. A lot of the power in electrolysis is lost in the 'resistance' of the electrolyte between the electrodes. As you also need a conductive barrier to seperate the hydrogen from the oxygen generated then that may constitute an extra point of loss.
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