Wikipedia:Reference desk/Archives/Science/2018 October 6

= October 6 =

KosherSwitch
As I discussed at Talk:KosherSwitch, I am having a bit of trouble figuring out [ https://patentimages.storage.googleapis.com/48/4f/8c/b1df4e115e8359/US7872576.pdf ]. In particular, I am having trouble with


 * "FIG. 3 shows an embodiment of the present invention including a device having one pair consisting of one transmitter positioned opposite one receiver. FIG. 5 shows an embodiment of the present invention including a device having two pairs, each pair consisting of a transmitter positioned opposite a receiver."

What is the point of the two transmitters and receivers (which anyone else would call light sources and light detectors)? Figure 7 shows one or the other being blocked. Why?

Because this is the refdesk (and because the religious aspects may be the reason for the two sets of light sources and light detectors); here is what I think is going on (and I know nothing about this other than what I found doing a web search):


 * Orthodox Jews are (usually) not allowed to light a candle of blow out a candle on the sabbath.


 * If an Orthodox Jews opens a window on a windy day, knowing that doing so will blow out a candle, this is considered indirectly blowing out the candle. I think that the rules are a bit different between direct and indirect, but I am not clear how.


 * An Orthodox Jew can light a candle before the sabbath and use it for illumination after the sabbath starts. Starting a fire that is not allowed, but the fire itself is. Likewise with electric lights.


 * An Orthodox Jew can light a short candle, knowing that it will burn out during the sabbath. This is not considered putting the fire out. Based upon this, it appears that setting a timer before the sabbath to start/stop an electrical appliance during the sabbath is allowed, and there are smart phone apps and wireless relays that are used to do things like cook a dinner on an electric stove.


 * If an Orthodox Jews opens a window on a non-windy day without knowing whether wind is in the forecast and later a wind blows out the candle, that is allowed. And he isn't required to close the window if he sees a wind coming up.


 * I am not clear about what happens if he knows that there is a 90% chance of wind, and whatever the rule is on that appears to be at the heart of whether the KosherSwitch is allowed.

Clearly there ate a lot of complexities that are going right over my head on this: see --Guy Macon (talk) 07:56, 6 October 2018 (UTC)
 * The implicit reasoning is that one can disown responsibility for exactly what occurs after one starts a random process because only the omniscient God can know it. The notion is similar to the medieval imposition of a Trial by ordeal: the end result was considered a "judgement of God" because one believed that God would miraculously intervene on behalf of an innocent accused (Secular objections that no such God exists, that the process is not random but pseudorandom meaning predetermined, or that human motivation cannot be so easily hidden from an omniscient God who does not intervene on human command are all notwithstanding.) The KosherSwitch arrangement with one Tx/Tx pair provides a delay from action to intended result of a duration that is pseudorandom if relying only on binary logic circuitry, or a greater degree of randomness could be introduced by means the patent hints about e.g. room temperature, room sound level etc. The notional divine intervention is to hinder a "succesful" transmission, or choose not to do so. The point of introducing two Rx/Tx pairs is to give an apparent symmetry of alternate possible divine interventions. In other words, there is no correlation between the binary result and God's choice whether to intervene. DroneB (talk) 11:55, 6 October 2018 (UTC) This response introduces only one reference link to the discussion subject that Guy Macon could have allowed to proceed at Talk:KosherSwitch where it belongs. DroneB (talk) 11:55, 6 October 2018 (UTC)
 * (joke) I have heard preachers say that we should leave things to God's choice, but they never liked it when I proposed taking all of my money and throwing it in the air rather than putting it in the collection plate. I figure that whatever God wants he can keep and whatever comes down is mine... --Guy Macon (talk) 19:01, 6 October 2018 (UTC)
 * This reminds me of the news report on the front page of the Guardian about thirty years ago describing a new Brazilian watch giving the prayer times and direction to Mecca anywhere in the world.  The publication date was Saturday, April 1. 86.152.81.16 (talk) 11:56, 6 October 2018 (UTC)
 * There is certainly no reason why one of the wearable GPS toys that large corporations sell to track their chattels couldn't be programmed to do that right now. Wnt (talk) 12:14, 6 October 2018 (UTC)


 * While we're off topic ... is there any rule against turning up a stove that is already on, or a light bulb on a dimmer switch? Because then there could be a bunch of appliances automatically set to come on at a very low level every seven days, where the "off" just means "very low". Wnt (talk) 12:26, 6 October 2018 (UTC)


 * Apparently not allowed. See

I don't think there are uniform "rules" for any of this stuff. It's a matter of interpretation and interpretations vary. 173.228.123.166 (talk) 14:02, 6 October 2018 (UTC)


 * I have been down the rabbit hole for hours, reading about rabbinic interpretations when my original aim was simply to add a section describing the electronics inside the KosherSwitch. There are some rules that come straight from the old testament and everyone agrees on. There are some that come from rabiis (often rabbis who lived centuries ago) that everyone agrees on. There are some rules that only one rabbi teaches. And then there are rules that are hotly debated. The whole thing reminds me of Wikipedia policies. :) --Guy Macon (talk) 19:01, 6 October 2018 (UTC)


 * Is there some reason you're trying to figure out from the patent what the purposes of the various functions are rather then their website (also the FAQ entries)? When I looked at it when someone brought up the switch a few days ago it seemed to explain at a basic level why they were doing stuff in certain ways. The manufacturer is obviously not unbiased and wouldn't be an RS for much but you've brought this to the RD rather than keeping it to the article talk page so I presume aren't simply looking for RS. In particular their religious reasoning should be treated with care (including  and the FAQ) but it at least lets you try and understand why they're doing what they're doing from their POV. One thing I don't think they dealt with is the pseudorandom issue, at least that I saw, still it sounds like your confusion is much more than that. Note they do deal with issues like advantages over times (basically obvious stuff, saving electricity and not having to be bound by the exact times of the timer). As 173 has said, and is clear from our article IIRC, obviously not everyone agrees whether the KosherSwitch is okay, as with most things surrounding interpretations of most religious laws. Nil Einne (talk) 16:57, 6 October 2018 (UTC)


 * My aim is to add a good engineering description of the electronics with, if I can, a description of why they did it that way in a NPOV manner -- carefully avoiding implying that they are right or wrong about what is allowable under Jewish law. Neither the "how" page or the FAQ appear to explain the reasoning or operation of the variation where there are two light sources and two light detectors. The one-detector version is called the "classic" but I am not sure whether the two-detector version is shipping, planned, or just something they threw into the patent. -- The religious aspects are interesting, but I am only going to edit the engineering description, other than removing things that clearly violate our NPOV or BLP policies. --Guy Macon (talk) 19:01, 6 October 2018 (UTC)


 * (Didn't properly read above reply) I belatedly realised I forgot to mention is if this is something do with the article, ignoring whether or not the RD is a good place to handle that, I'm not sure why the patent was brought up anyway. The patent is definitely not a good source for the article, as it's WP:Primary and as clear from the first post, requires a lot of interpretation which we shouldn't be doing. In fact, in some ways it's worse than the webpage. Nil Einne (talk) 15:47, 7 October 2018 (UTC)

I appear to be not communicating well, which I have to assume is my fault. Let me lay it out step by step so that there is less chance of miscommunication:


 * I am an experienced editor (12 years, 40,000 edits) and am well aware of our sourcing requirements. Please don't assume that asking a question about a patent equals a desire to use that patent as a source. There is nothing wrong with me using a patent to improve my own understanding. The reference desk is a good place to ask a question about the patent.


 * I am also an experienced electronics engineer who is working on a "principle of operation" section of the KosherSwitch article. To do this, I myself have to understand the principle of operation, and I am very wary of primary sources that were written to convince people that the switch in question is allowed under Jewish law. When, as often happens, the patent describes one thing and the marketing material describes something else, that tells me that I need to attempt to find a high quality reliable secondary source for that particular technical detail.


 * I am well aware of what original research is, but there is absolutely nothing wrong with using my engineering knowledge to guide my own personal research. For example, several reliable sources say that the switch moves a plastic tab to block a light beam. If I ran into what appears to be a reliable source that says that the switch moves a plastic tab to block a radio signal, I would know to look for a better source, knowing that radio signals are not stopped by plastic. Again, I am well aware of our sourcing rules and would not use my own knowledge to make a claim about the properties of radio waves.


 * Please assume good faith. I have been editing engineering and electronics articles for many years. This one has a religious aspect as well, but I have no plans to say anything at all about the religious aspect. I do find the religious aspect to be interesting, and would appreciate being allowed to ask questions about it at the reference desk without having somebody jump down my throat. --Guy Macon (talk) 16:55, 7 October 2018 (UTC)
 * I agree there's nothing wrong with using a patent to improve your understanding, my point is your question was very unclear as to whether you wanted info for personal understanding or for articles. The former is the primary purpose for the reference desk, and although people are fully entitled to demand sources of varying quality as to their preference, the default it that we're less strict than would be required as to the encyclopaedia proper unless the person specifies otherwise. As for the later, my first reply was worded a lot less clear than it should have been I apologise for that. There's nothing wrong with asking on the RD for helping finding sources for articles. The only thing is, it needs to be clear this is the intention since otherwise people are going to assume that sources which aren't acceptable for the article would be okay. Also it's generally better to at least try on the article talk page first i.e. give it fair few days. (To be clear, that's about finding sources. Disputes over article content, whether something is an RS etc shouldn't be brought up on the RD, but I didn't believe that was happening, not least because I saw no dispute.) The ultimately point is that clarity over what is desired is important. In particular, if someone brings up patents, most of us are going to assume their intention is personal knowledge and similar quality sources like produce brochures and webpages are also worth a look. Especially if we have reason to believe the person is capable of reviewing the source and picking out the parts which are probably correct and ignoring the parts which are questionable. So while such sources should always be used with care, in this case they IMO provided a decent explanation of what they did and their reasoning for doing so. They did for example mention they use light and so while it's good to confirm via secondary sources, it doesn't seem there was any reason to doubt this not least because as you also mentioned, using something else would likely be more complicated.  Anyway my first assumption was you wanted this for personal reasons, except that even your first reply, let alone your second was quite unclear since you were referring to a discussion on the article talk page which isn't the place to ask for help understanding how something works. So since I don't like to get into long back and forths, I covered as many bases as I could have.  (I have no idea why they said receivers etc in their patents but as I assume you're even more aware than me, there's a reason why competent patent attorneys are so expensive and people say patenting something without one is normally pointless. Getting the wording right is very important. Patents tend be sufficiently broad to ensure others can't simply modify some aspects and argue it isn't covered but not too broad it will be rejected. In the patent, they mention for example how a transmission could even be ambient temperature or ambient light, as well as radiological, chemical etc. Yet the actual examples they give in the patent also seem to be a light source (LED or laser), again as I'm sure you know even better than me, this tends to be how patents are worded.)  Your latest reply still seems fairly unclear to me. Are you suggesting there's some conflict between the patents and their website? If so, what? The only thing close is the two transmitter thing yet as I think you already acknowledged, there's no conflict since from what I saw their patent also included a one transmitter example, including flow chart and everything.  I agree the purpose of this is an interesting and unanswered question. The patent doesn't really seem to describe the point of the two transmitter version over the single one, other than how it would function including the possibility of an error condition if the signals didn't match. (Well their conditions should always be reversed.) And you're right their webpage doesn't seem to mention, which suggests it doesn't exist. I assume you're aware that while hopefully we will find something, the nature of this device means it's easily possible the best answer we can get may be simply whatever they say when asked. (I mean, unless there was actually some public and known discussion, even RS may have limited ability to actually come up with much more than trusting what they say about why they also made up the 2 transmitter version.)  While you're free to reject the websites description of how the device works out of hand, even if it doesn't AFAICT contradict anything in the patent I'd note that a lot of it is actually easy to check. E.g. whether it uses light, how many transmitters there are, whether it had the randomness and apparent failures etc. So these are the sort of things most slightly smart brochures sources don't lie about. Of course they could have introduced a 2 transmitter version and not updated their website or maybe only sell it to certain customers, although there's no particular reason to think they're going to hide this if asked. Precisely what the microchip is actually doing is as I'm sure you know a lot harder to check and I have strong doubts anyone really has. (The pseudorandom vs true random issue is an interesting question, but it looks a lot to me like they are using pseudorandom, their skirting the issue in the IndieGogo discussion for example .)  I'm not really sure what the relevance of AGF is. No one here seems to have failed to AGF. I'm also not sure who's "jump down my throat", as no one here seems to have done that. I'd note however the religious reasonings are questions which would be best dealt with at RDH not here. Even issues like pseudorandom vs random from a religious standpoint is not RDS material. I mention this solely because I, and I assume others, are not likely to reply much about the religious issues here instead concentrating on the science issues like how the switch works physically etc.  P.S. While the switch is mildly interesting, it's not really interesting enough that I'm likely to check out this discussion more. I would be more interested in any RDH discussion since frankly I'm not sure if there is any great mystery over the science stuff.  Nil Einne (talk) 00:09, 8 October 2018 (UTC)

d-orbital overlap in primitive metal lattice
My inorganic chemistry text book has this practice problem. You can see figure 3.66 here. The answer to the first part is fine enough. What I'm confused with is the Self-test 3.17. If I imagine a primitive unit cell like this one, with transition metal atoms at each of the verticies, then it seems to me the atoms should be able to overlap their d-orbitals with their nearest neighbors along all 3 axes. That could involve sigma, pi and delta bonding, and all d-orbitals would be able to participate. The answer guide however says, "The dx 2 -y 2 and dz 2 have lobes pointing along the cell edges to the nearest neighbor metals". Now I can kind of understand what they mean if they consider the orientation of the orbitals to be constrained in exactly the way they are shown in figure 3.66. But in a primitive structured metal there would be no reason that I can see for them to be stuck in that orientation when they could much more efficiently form bonds with their neighbors by rotating 45°. 139.194.67.236 (talk) 08:42, 6 October 2018 (UTC)


 * I'm not sure precisely what you're suggesting, but I should note that our article on titanium(II) oxide says that it is "non-stoichiometric" with many vacant sites in the crystal, and that "careful annealing" can produce a monoclinic form. I looked this up, though, and it is "monoclinic" in the sense that the vacancies in the rock salt lattice have been put into regular positions.   Looking at that structure I don't see a way for the atoms to get at one another more efficiently; the vacancies maybe have something to do with tweaking the Ti-O bond length to an optimal value?  Also, the Ti atoms seem to be making about 14 contacts each there (five to oxygen) which perhaps coincidentally would fill out a shell of 18 in a simple-minded way.  But the original diagram illustrates that the lobes make good overlap in this overall geometry, and none of this really changes that. Wnt (talk) 12:11, 6 October 2018 (UTC)
 * My question relates to the Self-Test 3.17 portion; "which d-orbitals can overlap in a metal having a primitive structure?" The answer to that self-test given in my answer guide seems to assume that in a metal the atoms would still be locked into the relative orientations that they take in TiO, but I see no reason what that would be the case. 139.194.67.236 (talk) 00:28, 7 October 2018 (UTC)
 * That makes sense. I should say that I'm actually having a hard time finding good examples - this site says only polonium crystallizes in a simple cubic structure, with which the Wikipedia article agrees.  And that's only one allotrope of it.  And it's scarcely a metal, being a chalcogen.  Just searching for the simple cubic I find the book's case more often  where indeed dxz, dyz, dxy are the stable ones but in a structure of alternating ions.  Now there is a paper I found when searching "polonium d orbitals" on Google Scholar, but it uses some strange new perversion of the web where the direct link gets a "not found" even though clicking the link from the search result finds it - despite having scripts off.  The name is "A study of the mechanical and structural properties of polonium" and it says polonium is an "s2p4 structure, with a large splitting between the s and p energy levels".  Not surprising for a chalcogen, I suppose.  I don't necessarily understand every last syllable, but the bottom line is that the only simple cubic metal in existence gets that way using px, py, and pz orbitals.  So you might have a point about the d orbitals ... but it seems moot either way. Wnt (talk) 01:32, 7 October 2018 (UTC)
 * Our article says polonium is a metal, which I think refers mostly to its electrical behavior. Chemically, it's in the same class as sulfur, selenium, and tellurium, but that's a different question.  Again going by our articles, tellurium is classed as a metalloid, selenium is said to be a non-metal but more rarely considered a metalloid, and I'm sure sulfur is unambiguously non-metallic except perhaps in allotropes that don't exist under ordinary conditions. --Trovatore (talk) 18:02, 9 October 2018 (UTC)
 * The chemistry of Po as we know it (which is to say not very well, given its strong radioactivity) seems to be more metallic than not, although it is a weak metal and many analogies to Te also exist. Its band structure is that of a metal, which is probably more relevant here. The large splitting between the 6s and 6p energy levels is a case of the inert pair effect. Double sharp (talk) 03:18, 10 October 2018 (UTC)
 * Ok, thanks. That's very helpful. A lot of the questions in this text seem to be like that: they're so esoteric and involve such purely theoretical scenarios that they can't just be looked up as such, and whoever wrote the answer guide seems to have just ran through the questions quickly and just guessed where they weren't sure, confident that the questions and their short answers were vague enough to ensure they're not even wrong. I suppose in a classroom setting that would help generate discussion when going through these problems, but I'm just reading by myself at home and I don't find them very useful.
 * In this particular case though, there are other examples of metals that form primitive unit cells, but they do so at elevated temperatures and pressures. Ca-III is one example. I can't find any information of their d-orbital orientations though (calcium doesn't have any occupied d-orbitals anyway). 139.194.67.236 (talk) 02:28, 7 October 2018 (UTC)
 * I just happened across a basic text that illustrates that crystal field splitting for an octahedral complex does favor the three orbitals you expect:  My guess is genuine simple cubic lattice of a metal ought to act the same way, since there are no bonds to the more distant metals more than one cube-edge away. Wnt (talk) 11:57, 8 October 2018 (UTC)

Dead ants in my home
I have strange little problem that I can't explain and I'm curious about it. In a ground-floor bathroom in my home, dead ants just keep appearing. Not just a few, but hundreds at a time. I vaccuum them up and then several days later they will be back. They never appear gradually, only a whole bunch showing up all at once, usually overnight. I have never seen a live ant in the area. I have never used any insecticides. I live in New Jersey, USA and they are the normal small black ants that are most common around here. Is this some kind of ant cemetery where they bring their dead? (But not immediately when they die - they would have to be accumulating bodies for a couple of days then dropping them off in a mass burial). What's going on here? And how do I stop it? Deadantspilingup (talk) 17:56, 6 October 2018 (UTC)


 * According to this National Geographic article ants regularly clear out their dead, so you are, perhaps, just the "lucky" recipient. Mikenorton (talk) 18:03, 6 October 2018 (UTC)


 * "Bring out your dead!" (Clang!) Obviously you have some live ants in close proximity. If I were in your situation, I would call a pest-control company, who could do some spraying and hopefully drive the living ones away and/or kill them. ←Baseball Bugs What's up, Doc? carrots→ 18:24, 6 October 2018 (UTC)


 * Indeed, from that article your bathroom must be right next to the nest for it to be a convenient disposal site. Mikenorton (talk) 18:39, 6 October 2018 (UTC)
 * Although I called it a "ground-floor bathroom", my property is sloped and the bathroom is actually about 3 feet above ground with nothing but cement foundation underneath. I have checked outside multiple times to see if there were ants climbing up the cement to find a way inside (finding a crack in the siding, or whatever), but I've never seen any.  If there is a nest somewhere that is clearing out their dead by putting them in my bathroom, they certainly aren't doing it the easy way.  Deadantspilingup (talk) 19:30, 6 October 2018 (UTC)
 * I say again: Call an exterminator. You'll be glad you did. ←Baseball Bugs What's up, Doc? carrots→ 19:33, 6 October 2018 (UTC)
 * Point taken. But I think I'll first try those bait traps where they take poisoned food back to the nest.  Hopefully the little buggers get real hungry carrying their dead siblings to the cemetery.  Deadantspilingup (talk) 19:40, 6 October 2018 (UTC)
 * It's worth a shot. ←Baseball Bugs What's up, Doc? carrots→ 19:43, 6 October 2018 (UTC)
 * Stating something kind of obvious, but you may not have thought about it: if you have some kind of camera you can set up to record continuously, you can use that to find out where they're coming from. I'm not sure the bait idea will work; I recall reading that colonial ants generally avoid areas containing dead members of the same species, because of the potential for disease. So, they might not take food from the area. --47.146.63.87 (talk) 05:41, 7 October 2018 (UTC)


 * This happened to my laundry a while ago. Eventually I found an ants nest in the ceiling, and they were pushing dead ants out the manhole. This might also happen though a light fitting. or air vent. Graeme Bartlett (talk) 08:58, 7 October 2018 (UTC)