Dog ticks gone completely

It's been 2 years since I started the war. This was a desperate war, the ticks were everywhere, even high on the ceilings and occasionally on my bed. I've tried many ways to get rid the ticks: spray, manually taking it day-in-day-out, vet injecting the dogs with anti ticks, special shampoo, medicated collar etc. Now, the ticks has completely gone from the environment of my house, the dogs sleep peacefully, their face contentedly saying thank you all the time, so beautiful.

The weapon was deltamethrin or so it says on the label, it was in the form of "magic chalk". It is easily obtained in Indonesia and cheap. I was very apprehensive at the beginning, afraid that it might be toxic to the dogs and humans. Indeed, there were 2 incidences when the dogs ate it, they didn't sick a bit, however. There was one time when perhaps the dog ate it too much, he threw it up but didn't show any sign of sickness.

So this is what I did:
Applied the chalk on the floor (draw a line with the chalk where the floor meets the wall), this is only at places where the dogs roam and sleep. The dogs play at the yard, but there is no way I can apply the chalk at the yard.

Apparently it took about one year for a full tick removal, the dogs brought the ticks from the yard but the residue of the chalk on their fur were still able to kill tick even after a month of applying the chalk to the dogs sleeping area. You will need to apply the chalk every 3 month and let it there for 2 days.

I believe the tick is "brown dog tick" or Rhipicephalus sanguineus

Try it. There is a bonus of this chalk. Cockroach that passes the chalk-line will be dead in less than 30 minutes.

Oh, I heard that magic chalk containing deltamethrin is illegal in US, but you can still find it in chinatown, however. It might be called Ant Chalk. It's illegal probably because no company has register it for home use in US, but I found it perfectly safe after checking Deltamethrin's MSDS. You can also find its information in wikipedia.

Noisy Split Airconditioner (or any induction motors) caused by power line harmonics

The noise sounds like beat frequency of 50 Hz and 44 Hz - a modulated 50 Hz (or 44 Hz) by 6 Hz envelop (Click here to hear). I tried to google and found no satisfactory explanation. The 44 Hz must come from the rotation of the compressor as it is driven by induction motor (a psc or permanent-split-capacitor motor actually) while the stator magnetic field rotates at 50 cps (1500 or 3000 rpm), the rotor rotates at 44 cps maintaining slip to develop torque. But why it wasn't that bad before?

To make it short, I found the answer after 2 months of investigation: it was caused by harmonics at the power line. I needed 2 months because I don't have proper tools to measure the harmonics, rms, refrigerant pressure, etc, all come in a sort of improvisation.

The remedy came after a lot trial and error, an inductor in series with compressor motor is the answer, I made a hand-wound inductor using an old transformer core, I don't think my cheap chinese DVM measured the inductance properly, it read 15.4 mH . Now the sound is like this, not just the noise is abated, the current drawn is also lower (measured by that DVM, average measurement).

Here is the inductor:

• Core came from old 220V to 15V 5 Amps transformer
• Core cross section is 4 cm x 2.9 cm
• 120 turns (I made 27, 54, 81, 108-turn taps), originally 108 was the final tap but turned out more inductance was needed and I only managed to add 12 turns without removing the bobbin from core.
• Here is the voltage waveform across the coil, the 3rd harmonics (150 Hz) is clearly shown
  

Vertical is 5 V/div, Horizontal is 5 mSec/div

• and here is the current across sensing resistor (R=0.047 ohm) in series with the coil

Vertical is 100 mV/div, Horizontal is 5 mSec/div

I should've captured the oscillographs with slow shutter speed, but I only realized it after, and it was taken outside the house in a bright and humid 34 C (92 F) day so I don't want to do it again. I do have the video of those oscillograms if a need arise latter.

Now how do people describe the sound of that noise:

• beat frequency noise?
• fluctuating noise?
• low frequency noise?
• rough noise?
• pulsating torque noise?