Wikipedia:Reference desk/Archives/Science/2019 June 18

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June 18

K9 breeding

Is it possible to interbreed different species of K9. I am aware that you can cross breed dogs but as Hyena's and foxes are K9s too,can you cross breed a large dog with a Hyena? I am not planning on doing this, I am merely curious if it is possible. has anyone tried this. The same goes for others in the K9 family, foxes, or wolves and hyena? Thanks Anton 81.131.40.58 (talk) 15:54, 18 June 2019 (UTC)

A quick Google search of the subject of what canines can cross-breed with, the answers are: wolf, yes; coyote, yes; fox, no; hyena, no. The reasons have to do with chromosome counts. And hyenas are not canines. They're more closely related to cats. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:23, 18 June 2019 (UTC)

I think it best to direct OP to crossbreed#Hybrid animals and canid hybrid. And Hyena. Gem fr (talk) 18:49, 18 June 2019 (UTC)

What about African Wild Dogs and jackals, can they be mixed with domestic dogs? — Preceding unsigned comment added by 81.131.40.58 (talk) 08:24, 19 June 2019 (UTC)

Jackals are several different species. There are hybrids between golden jackals and domestic dogs, see Jackal–dog hybrid, but the other species of jackal are far more distantly related, and I don't see any content about hybrids. African wild dogs are also much more distinct from domestic dogs than golden jackals, and I also see nothing about hybrids there. Someguy1221 (talk) 08:46, 19 June 2019 (UTC)

There are several dog wolf hybrids I believe dogs originated from the gray wolf and that is why it it easy to cross breed them especially with German Shepards and related breeds 64.222.180.90 (talk) 18:37, 20 June 2019 (UTC)

Electric engine speed or load monitor

I don't know what this is called, so I'm having trouble reading about it... Assume you have an electric motor. I doubt it matters if it is AC or DC. It rotates a spindle just like any other electric motor. Inside the motor there is a sensor. If the spindle is trying to spin faster than the motor is spinning, the sensor indicates that the spin is too fast or the load is too light. If the spindle is trying to spin slower than the motor wants it to spin, the sensor indicates that the spin is too slow or the load is too heavy. What would that sensor be called? I'm sure they exist, but I don't know the name of the sensor. 68.115.219.130 (talk) 18:43, 18 June 2019 (UTC)

Tachometer Andy Dingley (talk) 18:48, 18 June 2019 (UTC)

Types of Wheel speed sensor that may be used inside or outside electric motors include slotted-disk opto-isolators using Photodiodes and magnetic Hall effect sensors. DroneB (talk) 21:09, 18 June 2019 (UTC)

A bit off track from the question, but are there any motors that run on A/C? ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:41, 18 June 2019 (UTC)

most did, actually. Induction motor Gem fr (talk) 23:48, 18 June 2019 (UTC)

• Very few types of motor run on DC. Many run on AC. The two common types for DC are the permanent magnet brushed DC motor and the universal motor, which runs on AC or DC. Both of these use an internal commutator to convert the DC supply into an AC current within the motor, in phase with its rotation.

Rotary electric motors rely on some rotating magnetic field internally, generated by an AC current. The motor rotates at, or close to, some simple multiple of this frequency. The difficulty with AC motors in the first half of the 20th century wasn't in making them, but in controlling their speed. From the very earliest days of AC it was recognised that motors had great advantages in running from an AC supply, but they (mostly) would only run at one speed (Often a half or one-third speed option too, by some simple switchgear, but nothing to make a continuous change). DC motors, in contrast, could be speed-controlled almost from the outset. When these AC motors were used for the first electric railways, such as the Italian three-phase system, the motors would typically run at the synchronous speed, accelerating or decelerating to this speed quite effectively on their own, without any control gear being needed. This gave simple operation for freight services, but a rather rough (and speed-limited) ride for passengers, as the train drivers couldn't adjust their speed to the track conditions. Andy Dingley (talk) 01:56, 19 June 2019 (UTC)

I'm not sure exactly what you mean by the spindle is trying to spin faster than the motor is spinning, but governor (device) may be relevant. CodeTalker (talk) 03:49, 19 June 2019 (UTC)

Maybe a torquemeter? DMacks (talk) 12:31, 19 June 2019 (UTC)

It sounds like the motor and spindle are actually going the same speed, but you want to know whether the motor is driving the spindle or is a drag on it. The drag part could either happen if something else is driving the spindle, or if the inertia of the spindle keeps it spinning after the motor power is reduced. A strain gauge would tell you which is the case based on if it is in tension or compression. It measures microscopic stretching of the material (strain), which tells you how much of a torque is applied (stress). Or, alternatively, you could just measure the speed of the motor/spindle assembly, and compare that with the power being used by the motor. This info could be combined to figure out how much of a drag there must be on the motor (assuming it's working properly), or even if it was getting "help" from the spindle. SinisterLefty (talk) 14:27, 19 June 2019 (UTC)

That sounds like a shaft torquemeter (which isn't anything like a dynamometer). They're not usually very successful trying to use a strain gauge for this, as strain gauges are good at measuring 1-dimensional strain and this is more like a 2-dimensional shear. The usual measuring technique is more like a phase meter, measuring the torsion between two ends of a narrowed quill shaft. Put a pair of discs on the shaft, one with a radial slit, one with a spiral slit. Shine a collimated light beam parallel to the shaft and you'll see a narrow spot, once per revolution, where the slots cross. As the shaft twists, their relative position changes and the spot moves in and out radially. There are many variations on this idea. Andy Dingley (talk) 16:31, 19 June 2019 (UTC)

If a torquemeter and a dynamometer are nothing alike, the redirect from the first to the latter should be replaced by an actual article on torquemeters (or we could just redirect them to Torquemada and call it good). :-) SinisterLefty (talk) 01:20, 20 June 2019 (UTC)

The fundamental task of a dynamometer is to apply a braking load, secondly to record that force (or torque). The torquemeter only measures, it doesn't apply a brake. Andy Dingley (talk) 01:37, 20 June 2019 (UTC)

Solubility of salts in presence of other salts

Is the solubility of a salt like sodium chloride modified when potassium chloride is also present in various mole fractions up to saturation? A similar question for potassium chloride in presence of sodium chloride! A similar question for sodium chloride in presence of potassium bromide! How does the non-ideal nature of the mixture influence solubility of each salt in presence of the other? Thanks!--37.251.220.173 (talk) 21:25, 18 June 2019 (UTC)

If you mean "can I dissolve less NaCl in a KCl solution" then short answer: yes. Solubility#Solubility_of_ionic_compounds_in_water indicates why. You'll find more info in Category:solutions Gem fr (talk) 22:33, 18 June 2019 (UTC)

See also Solubility equilibrium#Common-ion effect catslash (talk) 22:43, 18 June 2019 (UTC)

How do the ionic strength and activity coefficients influence the mixed salts solubility? Are there any predictive models? --37.251.220.173 (talk) 15:46, 19 June 2019 (UTC)

The most basic model is simply to solve for conditions that satisfy all relevant equilibrium constants simultaneously. Someguy1221 (talk) 16:23, 19 June 2019 (UTC)

I see that strontium sulfate page says something very interesting re the rather low solubility of this salt in water, around 14 mg and the much higher but unspecified value of solubility in presence of alkali chloride like sodium chloride (uncommon ions). How can this situation be explained?--37.251.223.163 (talk) 22:10, 23 June 2019 (UTC)

Our common-ion effect article mentions several patterns for apparent exceptions. Sounds like there may be some chlorostrontium complex being formed but I’d have to pull my inorganic-chem text later this morning to confirm. DMacks (talk) 00:05, 24 June 2019 (UTC)

Looks like [SrCl₄]^2– is a fairly stable complex. See the oil-wells refs I just added to the strontium sulfate article for some details about the effect of chloride on SrSO₄ solubility. DMacks (talk) 04:15, 25 June 2019 (UTC)

I'm seeing the following as a lead ref that is at the root of many citation chains regarding chloride effects on the solubility: [1] DMacks (talk) 14:41, 26 June 2019 (UTC)