Wikipedia:Reference desk/Archives/Science/2016 June 25

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June 25

Having Only Bread and Water = Plugging Up Gastrointestinal Tract?

On an episode of NCIS, it was mentioned that an old naval punishment involved feeding offending sailors only bread and water for a week, in order to plug up their gastrointestinal tracts. In real life, will such a diet really have the aforementioned consequences? 173.68.173.114 (talk) 03:41, 25 June 2016 (UTC)

I'm not aware of any such effect, and don't see why it would be the case -- however, such a diet would lead to malnutrition over time. 2601:646:8E01:7E0B:BC8F:CE52:F743:E9A9 (talk) 04:31, 25 June 2016 (UTC)

Yeah, that seems like pretty typical bad fact-checking on an apocryphal tale. No basis in physiological reality whatsoever. Point in fact, the bread of the era being likely to be high in fiber, it is more likely to have pulled additional moisture into the bowel (leading to looser stools) when compared against much of the rest of the preserved fair that pre-modern navies depended upon. Quite the opposite to the scenario presented, it would be the withholding or limiting of water rations (rather than providing an excess of water and fiber) that would be most likely to induce constipation in that scenario. Certain varieties of bread might have had the desired effect, but the last thing a naval vessel would ever want was to punish through means that would then require additional and highly valuable quantities of water to reverse, especially when withholding those same rations from the start would be a more effective punishment (being at sea with minimal water borders on one of the most physically unpleasant states of being manageable for a human being).

Interestingly enough though, modern navies prefer to punish their malcontents by making them watch episodes of NCIS. ;) Snow ^{let's rap} 06:26, 25 June 2016 (UTC)

Bread and water punishment was available in the US Navy until 1995 - see Non-judicial punishment. I don't know how often it was used during the 20th century, though. Tevildo (talk) 11:07, 25 June 2016 (UTC)

Apparently resurrected for civilians in Maricopa County, Arizona in 2014, according to this news article. Alansplodge (talk) 11:44, 25 June 2016 (UTC)

Although it was removed as an authorized punishment by USN court-martial in 1995, confinement on diminished rations or bread and water for not more than 3 days is still an available non-judicial punishment which may be imposed on US sailors and Marines of rank E-3 and below who are attached to or embarked in a vessel. -- ToE 12:27, 25 June 2016 (UTC)

Yes, just so. Reduced rations, especially radically reduced rations at sea, are always bound to be a much more feared punishment than being given just water and bread, but plenty of it. Snow ^{let's rap} 14:02, 25 June 2016 (UTC)

Main Battle Tanks -T-14 Armata

I studied the design of T-14 and I found a problem , the designers made an unmanned turret so they put the commander`s position in the front , but I imagined a scenario as this : the tank`s panoramic sight is disabled , the driver`s rear camera is disabled , the crew can`t see what`s behind them , do you consider this a big problem ? 94.249.115.70 (talk) 10:39, 25 June 2016 (UTC)

See T-14 Armata for our article. Your concerns are mentioned (with references) under "Sensors and communication". Tevildo (talk) 10:42, 25 June 2016 (UTC)

The Armata is probably Israel's best design of MBT. The trouble is that it's Russian.

The Armata concept is that of the Merkava, but even more so: the crew are the most valuable aspect so must be protected. It assumes the opposition are poorly supplied, few in number and easily discouraged. Yet Soviet tactics have always favoured the meatgrinder. Nor has Soviet ability to deliver a technical fix, and the untried Russian ability, ever been convincing.

In any combat, a working Armata wins the first round. But repeated attacks can attrite any such system of reactive armour. A rain of mortar shells will do it, so long as there are also enough mortarmen to deliver them. After a few rounds of such defence, the Armata is much less well protected.

There's also the question of whether an Armata can get to the battlefield and how much working electronics it brings along with it. You'll notice they've kept the glass viewing periscopes. Andy Dingley (talk) 11:35, 25 June 2016 (UTC)

So it`s an impractical tank as I supposed.94.249.115.70 (talk) 11:40, 25 June 2016 (UTC)

_If_ it works, it's great. Andy Dingley (talk) 14:45, 25 June 2016 (UTC)

That`s it .94.249.115.70 (talk) 20:58, 25 June 2016 (UTC)

Primitive semi-radius tachyons

As they almost said in The Matrix, for this mission we're going to need drugs... lots of drugs. Or science, if you're into the hard stuff. Pass those red pills and buckle up, cause Kansas is going bye-bye!

From "String Theory Co-Founder: Sub-Atomic Particles Are Evidence the Universe Was Created", CBS News:CNS News!

"Dr. Michio Kaku ... says theoretical particles known as “primitive semi-radius tachyons” are physical evidence that the universe was created by a higher intelligence."

After analyzing the behavior of these sub-atomic particles - which can move faster than the speed of light and have the ability to “unstick” space and matter – using technology created in 2005, Kaku concluded that the universe is a “Matrix” governed by laws and principles that could only have been designed by an intelligent being.

CBS refers me to a paper that I'm not getting in a readable form and this blog which makes its own curious claims like

Michio Kaku used a new technology created in 2005 that allowed him to analyze the behavior of matter at the subatomic scale, relying on a "primitive semi-tachyon radio." Tachyons ... are theoretical particles able to "take off" the matter of the universe or the vacuum contact with it, thus leaving the matter in its purest form, totally free from the influences of the world around them.

But what is this stuff? I mean, how are "primitive semi-radius tachyons" defined, what does that even mean? What is the new technology from 2005? What the hell is taking off? And so on... Wnt (talk) 14:42, 25 June 2016 (UTC)

Update: I have two sites [1] [2] which say that "primitive semi-radius tachyons" is a news garble that was never actually said - what was said is not so clear. But that doesn't take away from the weirdness of unsticking matter, matter in its purest form &c. Wnt (talk) 14:53, 25 June 2016 (UTC)

A Tachyon is a hypothetical particle that moves faster than light. Faster-than-light particles cannot exist because they violate the known laws of physics. AllBestFaith (talk) 14:57, 25 June 2016 (UTC)

It's plausible that Kaku would talk about tachyons. Tachyon condensation is real physics (it's part of the Higgs mechanism), and Kaku is fringy enough to believe in the faster-than-light kind of tachyons also. It's the "primitive semi-radius" part that makes no sense. -- BenRG (talk) 18:13, 25 June 2016 (UTC)

If tachyons do not interact in any way with normal matter or energy (and thus can never be detected or observed) they violate no laws of physics. Alas, the existence of such a tachyon can never be proven or disproven. --Guy Macon (talk) 18:18, 25 June 2016 (UTC)

I think this post by Franck Parra may be the origin of this. Here are some of his other posts, for comparison. It looks like "The Blog of Mystica" may have, for some reason, edited Parra's stream-of-consciousness writing into something more reminiscent of a press release, and republished it.

In any case, it is gibberish. Maybe it's vaguely related to something Kaku once said as filtered through the head of a crazy street person, but it's probably a waste of time to try to figure it out. -- BenRG (talk) 18:13, 25 June 2016 (UTC)

Wow. That 2013 posting definitely forms a clade with this news article, though the authors are not the same. I realize now this was CNS News - I hadn't looked closely before and for some reason I'd thought it was some local CBS affiliate. It is apparent that they are in serious need of scientific help. Wnt (talk) 20:11, 25 June 2016 (UTC)

I still suspect that Parra's post was the origin of this in English, but here's a version from November 2009 in Portuguese (which is probably Parra's native language). "Primitive semi-radius tachyons" has to be a garbled translation of "semi-raio primitivo de táquions". I don't know Portuguese (I do know some Spanish), but the only occurrence of "semi-raio" in the Portuguese Wikipedia is in Hilbert's axioms where the English article uses "ray" in its geometric meaning of a half line. I wonder if that Portuguese phrase is itself a garbled translation of something like "primordial ray of tachyons", which is a phrase that Michio Kaku might actually utter.

This version also says "the complete theory will be presented on January 9, 2010, at a conference in Switzerland", and credits the story to Scientific American. I doubt that Scientific American would publish anything resembling this story, and I can't find the conference. -- BenRG (talk) 00:34, 26 June 2016 (UTC)

Some Spanish-language sites, such as [3], attribute this story to "Jornal VDD", which is a fake-news publication from Brazil (it's mentioned in pt:Noticiário satírico). I bet that's the real origin. -- BenRG (talk) 01:50, 26 June 2016 (UTC)

NEMO as an illness

Trying to get data to fill out the description for File:North Livingston Baptist Church.jpg, I found their Facebook page, which had a request for people to be tested for a bone marrow donation. Part of that statement says This drive was set up for Mason, a local boy with NEMO, which is even more rare than HLH. HLH I suppose is Hemophagocytic lymphohistiocytosis, but what could NEMO be? NEMO lists a lot of things that aren't relevant; I suppose it could be a reference to a problem with IKBKG, but that seems a bit of a stretch. Nyttend (talk) 14:54, 25 June 2016 (UTC)

http://www.gosh.nhs.uk/medical-information-0/search-medical-conditions/nemo-deficiency-syndrome -- Finlay McWalter··–·Talk 15:02, 25 June 2016 (UTC)

I created a "stub" article based on that reference at NEMO deficiency syndrome and added a link in the disambiguation page for NEMO. Hopefully more information can be added there as it becomes available. One of the things that makes the ref desk useful is in finding gaps in Wikipedia's coverage - so this kind of question (and our response to it) is important to us. SteveBaker (talk) 17:33, 25 June 2016 (UTC)

Momentum conservation

This discussion has been closed. Please do not modify it.
The following discussion has been closed. Please do not modify it.
[section header added:107.15.152.93 (talk) 18:41, 25 June 2016 (UTC)] If there are any mistakes in the following supplement for Momentum conservation, please correct them. [The Supplement] In a closed system (one that does not exchange any matter with its surroundings and is not acted on by external forces) the total momentum is constant.(the momentum conservation 1st law) However, only in case of a physical system (called a newly semi or sub-closed system) that does allow certain types of transfers (such as transfer of mass and/or matter) inside the closed system, the total momentum is "variable".(the momentum conservation 2nd law) There are the following justifiable reasons. In the first place, the law of momentum conservation has been implied by a principally action-reaction law as below. [The mainly existing definition of the Newton’s third law] ~When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.~ However, the above law should be reformed (revised) as follows because it isn't so easy to distinguish the action-reaction forces from the equilibrium of forces in the above fixed definition. ~When one body (A) exerts an action force on a second body (B), the second body (which does not exert an action force by itself) simultaneously exerts a reaction force equal in magnitude and opposite in direction on the first body. And when A body’s action force interacts with B body’s action force, the equilibrium of forces between A & B are lost in case of (the initial) unbalanced momentums of the both bodies. But, each body receives a reaction force equivalent to the action force by its body from the other body.~ Note : The force (F or -F)’s reference value for an equation of momentum conservation in a collision of two bodies is chiefly based on a measure of one body’s action force (F) or reaction force (-F). That doesn’t indicate a pair (equal) of A body’s reaction force & B body’s action force in case of applying a pair (equal) of A body’s action force & B body’s reaction force as to F=-F.　 So, it is necessary to be careful of being in “uniform motion”, not “at rest” in the law of inertia for the united body in case of causing a perfectly inelastic collision by unbalanced action forces of the two bodies. As for the above important matter, even a main (hollow) body in the sub-closed system (just like EmDriving machine) that does allow certain types of transfers (such as transfer of mass and/or matter) in the same system under the momentum conservation law (which is similar to the law of inertia) could be applied. That means one and the same body may move at a constant velocity, not remaining at rest, once it produces some internal pressure difference (unbalanced forces) inside (at both ends of) the hollow body. The movement has been already proved with the successful EmDrive tests by NASA etc. — Preceding unsigned comment added by More-kenlouise (talk • contribs) 18:15, 25 June 2016 (UTC) Nonsense. See: NASA: Is Warp Drive Real?] You Still Shouldn't Believe in the emDrive Did NASA Validate an “Impossible” Space Drive? In a Word, No. No, NASA has not verified an impossible space drive! "The concept gained considerable press attention in 2015, after someone at NASA lab Eagleworks, which specialises in investigating almost-certainly-wrong Hail-Mary ideas on a 'what if' basis, tried out the idea and the press went nuts with the notion that this constituted NASA endorsing it." 4 Reasons Why The EM Drive is Probably Bullshit RF resonant cavity thruster#EmDrive --Guy Macon (talk) 21:19, 25 June 2016 (UTC) What? Nonsense!? What do you mean by...?? I (More-kenlouise) have asked about any mistakes in the above matter. You cannot correct them at all??? — Preceding unsigned comment added by More-kenlouise (talk • contribs) It is quite hard to understand what you wrote. Sentences like "That doesn’t indicate a pair (equal) of A body’s reaction force & B body’s action force in case of applying a pair (equal) of A body’s action force & B body’s reaction force as to F=-F" are almost incomprehensible. You seem to be arguing that A's "action force" on B should be distinguished from B's "reaction force" on A. But there is no such classification of forces in Newtonian physics. You also seem to argue that with A and B each acting on each other, and each reacting to the other's action, there could be unbalanced forces. But that isn't true. If A acts on B with a force FAB and B acts on A with a force FBA and there are matching reaction forces, then the total force on A (action+reaction) is FBA + (-FAB) and the total force on B (action+reaction) is FAB + (-FBA), and those are negatives of each other. -- BenRG (talk) 05:17, 26 June 2016 (UTC) A's "action force" on B should be distinguished from B's "reaction? force" on A?? That isn't true. A's "action force" on B should be distinguished from B's "action force" on A. Read the following sentences. ~When one body (A) exerts an action force on a second body (B), the second body (which does not exert an action force by itself) simultaneously exerts a reaction force equal in magnitude and opposite in direction on the first body. And when A body’s action force interacts with B body’s action force, the equilibrium of forces between A & B are lost in case of (the initial) unbalanced momentums of the both bodies. But, each body receives a reaction force equivalent to the action force by its body from the other body.~ — Preceding unsigned comment added by More-kenlouise (talk • contribs) 06:15, 26 June 2016 (UTC) ‎ More-kenlouise, I just gave you several links correcting the many mistakes in your claims, particularly your false claim that "the movement has been already proved with the successful EmDrive tests by NASA etc". Read them. I especially recommend the article at [ http://www.popularmechanics.com/science/a15323/temdrive-controversy/ ]. Also, read the warnings at User talk:More-kenlouise#June 2016. If you continue your disruptive behavior you will be blocked from editing Wikipedia. --Guy Macon (talk) 05:26, 26 June 2016 (UTC) And still, you cannot correct ... at all???? If so, you are disqualified for blaming me!!! — Preceding unsigned comment added by More-kenlouise (talk • contribs) 13:42, 26 June 2016‎ (UTC) Call for close Could an uninvolved editor please close this thread? Clearly we have WP:CIR and WP:IDHT issues here, and any further disruptive behavior should be be addressed at WP:ANI Disruptive behavior!? That's a bit much. How did More-kenlouise take any more of such a behavior? Do explain it before the closing!! — Preceding unsigned comment added by More-kenlouise (talk • contribs) 18:37, 26 June 2016 (UTC)

selective amidation

Here's something I wasn't taught in chemistry class: I have a peptide containing serine, tyrosine and a C-terminal proline. I wish to amidate this proline residue with ethylamine (not necessarily directly), but without functionalizing the tyrosine and serine residues. Is this possible without use of expensive protecting groups? Yanping Nora Soong (talk) 18:16, 25 June 2016 (UTC)

GFCI mystery

I recently installed an electrical outlet on my outdoor deck. Naturally I used an outlet with an integral Ground Fault Circuit Interrupter. (110 VAC, North American practice.) It's a brand-new, commercial grade, heavy-duty, 20 amp, outdoor-rated outlet. I assume it has the latest and greatest circuitry, it even has a little LED indicator that glows green when it's working correctly. I installed it in a weatherproof outdoor box with a weatherproof outdoor cover, whole nine yards.

But the first time I tried to use my portable circular saw with it, it tripped immediately. This was 100% repeatable: every time I reset it and tried the saw again, it tripped again.

The saw works fine in a different GFCI outlet, and it's a double-insulated saw with a 2-wire plug, so it's unlikely to have a ground fault. I considered that I might have wired the outlet incorrectly (it's all too easy to wrongly connect the supply lines to the downstream load terminals), but I double checked, and it's fine.

I wondered if commutator noise from the saw's 15-amp motor might be tricking the GFCI's sensitive detection circuit into tripping. I grabbed a heavy-duty extension cord (12 gauge wire, 25 or so feet long) and plugged the saw into that and the cord into the outlet, imagining that perhaps the cord's inductance might be enough to filter out the noise and keep the GFCI from tripping.

It worked! I've been using the saw all afternoon, and the GFCI has only tripped once.

So my questions are, has anyone heard of this problem, is my diagnosis accurate, and is the extension cord's inductance likely to be helping? (Or is there something else completely different going on?) —Steve Summit (talk) 18:59, 25 June 2016 (UTC)

Did you put this outlet on a circuit that already has a GFCI at the panel? I've found this can cause problems. Shock Brigade Harvester Boris (talk) 19:02, 25 June 2016 (UTC)

I've been having troubles with GFCI's at my home - four of them (two in the kitchen, one in the garage and one in the bathroom) would trip all the time with a variety of different appliances - sometimes consistently, sometimes just at random. The others are in places where we rarely use them - so it's possibly that they have problems also.

I asked around about the problem - and was told by an "experienced electrician" over on Quora that very often the problem is when the GFCI has additional outlets attached "downstream" of it using the "LOAD" terminals. The explanation was not very coherent (the guy had evidently been taught that this isn't an ideal arrangement - but didn't seem to be able to explain why). He recommended replacing all of the outlets in places like workshops and kitchens with individual GFCI's rather than sharing a single GFCI among several outlets.

That seemed like a painful thing to have to do (we have ~100 outlets and GFCI's cost ~$10 each!) - and so I first tried replacing one of the troublesome GFCI's with a brand new one. Result: No more tripping out with any of the troublesome appliances. So then I replaced the other three problematic ones - and now I have no problem with those either. In the course of doing that, I found one that had been incorrectly installed ("LINE" and "LOAD" were swapped) - and one that had (worryingly) been wrapped around with half a dozen layers of painter's tape to prevent it from coming in contact with a grounded metal box in the wall that had evidently been bent during installation! (Yeah - not even electrical tape!)

However, I'm becoming convinced that either these things get worse with age (although my house is only 10 years old) - or that there are some cheap/nasty brands that should be avoided - so as I have time, I'm gradually replacing all of the GFCI's in my house with new ones...not least because I fear other "botched" installations.

What I imagine would be the best course of action for you would be to disconnect the "downstream" outlets from the GFCI and see if it'll still trip with your saw. To be honest, I prefer to have separate GFCI's on all outdoor outlets anyway and at $10 each, there isn't really a good reason not to do that.

Failing that, you could also try replacing the GFCI with one from a different brand.

SteveBaker (talk) 19:37, 25 June 2016 (UTC)

You may want to invest in some higher quality GFCIs rather than the cheap $10 units you are considering. In my professional opinion (I am an electrical engineer), the GFCIs listed here are the best available. --Guy Macon (talk) 20:02, 25 June 2016 (UTC)

In my case, there is not a GFCI in the panel upstream of the outlet in question, and no additional loads downstream.

The outlet in question is name brand (Leviton), and was not inexpensive -- closer to $20 U.S., I believe. —Steve Summit (talk) 11:36, 26 June 2016 (UTC)

You started an inductive load (a large motor), which is a recognised problem for use with GFCIs. Some ratings will be less sensitive to such inductive loads (there may be deliberate time delays etc.), but it's unlikely that a consumer grade socket will be doing this. Also it's a general rule for such things that the integral types are more cheaply made and less reliable than the better grades, which are only available as separates. Also outdoors is a poor environment for switchgear anyway, so installing the breaker indoors at the panel may be more reliable.

Also, even though double insulated, I'd PAT test the saw, specifically the insulation. Hand-held power tools get a hard life. Andy Dingley (talk) 20:12, 25 June 2016 (UTC)

Thanks, Andy. I used to like the panel-mount interrupters, but I've gotten the strong impression that everybody else wants to be able to see at the outlet that it's a GFCI, not have to rely on someone's assurance that there really is one wired in somewhere else. —Steve Summit (talk) 11:36, 26 June 2016 (UTC)

I don't know this topic, but I'm suspicious the saw simply has very low resistance when the current first starts flowing (i.e. inductive load). If so, is it the added inductance of the electric cord that matters, or simply the resistance? For that matter, I wonder if you took some steel wool and burnished the plug on that cord until it looked like it was freshly bought, whether it would stop preventing the GFCI from going off. Not sure you want to try that :) Is there any little gizmo available that can be put on the end of a plug or into a light socketelectrical outlet that provides extra resistance for about one second only, then drops to near zero, specifically to stop such troubles? I'm thinking of something that would decrease in resistance drastically when heated for example, or it could be solid state. Wnt (talk) 21:37, 25 June 2016 (UTC)

This would be something like a Motor soft starter. The ones I'm familiar with are panel-type devices or are attached to the motor itself, not plug-in consumer-grade products. Shock Brigade Harvester Boris (talk) 22:11, 25 June 2016 (UTC)

See also: load controller (or not) ... Try a web search, I guess. This might be a solution, but I'm not an electrical engineer. --107.15.152.93 (talk) 00:42, 26 June 2016 (UTC)

Reducing the switch-on current to a motor will reduce its starting torque, possibly causing it to stall. AllBestFaith (talk) 17:57, 26 June 2016 (UTC)

My anecdotal experience (FWIW) relates to an HVAC motor with a similar problem, which was fixed by a load controller. --2606:A000:4C0C:E200:DCE4:1C76:57D1:F610 (talk) 18:33, 26 June 2016 (UTC) [aka:107.15.152.93]

You won't stall a saw at switch-on, because they're disconnected from the load when started, then pushed mechanically into it. You might do this with a device that can't disconnect its load.

It's typical for woodworking machinery (i.e. fixed machines) that cheap ones use universal motors (brushed), larger ones use induction motors. Universal motors offer higher starting torque and much higher starting torque / cost. They also only need simple switches, not starters. They do though have high inrush currents, violent starting with a snatch, and are much noisier. For woodworking there's a good example of this for table saws, where a portable "contractor saw" has a lightweight pressed steel table and a universal motor. The otherwise similar joinery workshop "cabinet saw" instead uses a heavy cast iron table, an induction motor and a price up to ten times higher. Andy Dingley (talk) 13:12, 27 June 2016 (UTC)

The inductance of a 25 foot extension lead has a trivial effect at 60 Hz, so that's not what's solving the problem. The resistance of the lead is reducing the Inrush current, the current that flows when the motor's armature is stationary. As soon as the motor starts turning, the current drops dramatically. Akld guy (talk) 21:04, 26 June 2016 (UTC)

Ah, following that link at least answers my question above: the device I asked about would function as an inrush current limiter and would be made of a Negative Temperature Coefficient thermistor. The first one I found online is a little bigger and a lot more expensive than I'd been picturing [4] (even after Brexit!), but it can handle 220V so presumably a 110V wouldn't be as pricey. Wnt (talk) 10:02, 28 June 2016 (UTC)

The reason for the cost there is the name "Canford" on the side. Andy Dingley (talk) 10:41, 28 June 2016 (UTC)