Saturday, March 26, 2016

Back, after visit to Canada

While we were back in Canada we had a surprise visit to the Nanaimo hospital. It went like this: After dinner Carole starts to get what feels like a cramp in her gut. It gets worse and worse, to the point that she is literally crying from the pain. But rather than going to the hospital Carole wants Bill to call the nurses hot line to see what they would suggest. Bill made the call and opened a case and was left on hold waiting for a nurse to be available. Meanwhile, Carole, not able to move made some comment about what the nurse might decide. Finally Bill said the only decision to be made here is whether I drive you to the hospital or we call the ambulance. We drove to the hospital.

It turned out Carole had a gallbladder attack and ended up getting her gallbladder removed. This was surprising and shocking as we kind of had a vague idea of what the gallbladder does but neither of us knew that it is something we can easily live without. So we weren't prepared to be suddenly faced with the decision of removing it or not. In the end, it seemed better to have it done in Canada rather than facing the possibility of another attack and an operation in China. So, Carole underwent the knife. very small incisions though, its called laparoscopic surgery:
It was 24 hours in the hospital before the operation actually took place but then we were both home again by noon the following day. Then Carole had recovery time (no lifting, limited mobility and little appetite) interspersed with tests, doctors visits and all sorts of things in Nanaimo in addition to the dentist and naturopath appointments we had already scheduled in Victoria. One of the tests was in a fancy MRI machine that we had previously only seen on TV. And yes it looks just like on TV (this isn't the actual one, we searched the internet for a photo and chose this one for the green, cold, hue):

But Carole wasn't prepared for the experience of being inside it. She describes it as being "locked in a tube listening to the critical mother's voice barking orders at me."  In fact there was a mechanical voice coming from her sound-protection headset, slightly over top of the mechanical thumps and whirs of the machine, telling her "Breath in.  Breath out.  Breath in.  Breath out and hold..."  She describes it as a very one-sided conversation, and no apparent escape!

Finally, three weeks after the operation is when our flight back to China was scheduled and the doctor gave us the go ahead, so off we went. Of course Carole was still on her "no lifting" restrictions to I was entrusted with 4 extremely large checked bags and 2 carry-on bags, while Carole walked slowly beside me.  Carole felt guilty and I felt...burdened, although somewhat heroic. We had the maximum allowed checked baggage: 4 suitcases of maximum dimension, each of which was a few ounces under the maximum 50lb.

Our arrival here was a bit rocky since while we were away a pipe froze and burst in our house and the repairs were not quite finished when we got home. Also the underground pipes to the restaurant across the street froze and it was closed till further notice so now we had to start cooking at home which is doable but requires shopping for food. We made a couple of trips into Yanqing but then found we could get by just shopping at the village market. So I would go every five days to stock up on fruit, vegetables, peanuts and tofu. Sometimes we'd get adventurous and buy something unknown. Of course my level of communication at the market consists of asking how much something costs so I can give them the correct amount of money, so unknown foods remain unknown till we take it home to try it. Like this stuff:
We actually posted this picture on Wechat (the Chinese replacement for Facebook) hoping someone could tell us what it is. We never did learn what it is. But it sure seems like a kind of tofu, even though it is green. we ate one slab of it in our hands as if it were flatbread. The next day we sliced up the rest to add to a stir-fry.

Also by the time we got back, the company we worked for had merged with a division of another company. They now have more than twice the staff as before and they say they will have to renovate the basement of our house into offices for 6 staff members. Also they have not yet settled into the new structure and its even more chaotic than before, from our perspective anyway. At any rate they are not yet organized enough to have much for us to do, so fortunately we have time to shop for food and can actually enjoy our fresh food and home cooking.

The final straw of our rocky start back here is that we had almost 2 weeks of heavy, heavy, heavy pollution days. So, since we had spare time and were listening to our air purifiers all day long, I embarked on a sound dampening project. The result was transforming the left fan below left to the sound insulated version on the right.
But of course those of you subscribed to the online blog would know this already. I posted the whole story here but since it is more of a technical story and not really about us, I didn't send it out by email to everyone.

So, yes, by the time we had the sound levels down on our fans we were happy, and then the smog went away and we were even happier. The amazing thing I noticed while walking outside is that the hills now look to be three dimensional. I had gotten used to seeing them through the haze and looking like cheap movie set backdrops. What a difference fresh air makes.

Here are what the hills look like from our back porch on a clear day:
With the new clean outdoor air I finally felt comfortable spending some time outside mounting the new wind chimes we got while we were away. We got the bamboo chimes in Vietnam and the glass/rock chimes in Canada. We knew we liked the sound of each of them when we got them but didn't know what they would sound like together. We just love them. Here's a little video where you can hear how they sound together:

We are able to enjoy it here now, breathing fresh air and listening to our wind-chimes while we wait for the organizational restructuring and the house repairs and renovations to settle down.

Wednesday, March 23, 2016

Air Purifiers

We have been back in China now for a bit over 2 weeks and right away we were hit with some pretty heavy smog days. There were a few days when the PM2.5 particulate levels were consistently above 250 µg/m³ (this is ten times the WHO recommended safe levels) with peaks up to 500 µg/m³.

[This where Carole suggests warning you that this is a very technical entry.  You've been warned.]

For example, this shot looking down on our neighborhood from the hill behind us was taken on a day with approximately 250 µg/m³ particulate count. On days of 500 µg/m³ it is much soupier. On those days we can still see across the street but, if one we were to see a person about one block away, we probably couldn't tell if its a person or a bush.

This is just life here in China, something we all have to deal with. I've already mentioned here that we use our 3M face masks when we go outside in these conditions. How about when we are at home? Well the government recommends people stay indoors when levels are elevated. That helps, a little, but indoor particulate levels are still about 30% to 50% of outdoor levels, higher if you don't keep the doors and windows closed 24 hours/day. So we run air purifiers at home.

We discovered the best deal on air purifiers is from a Beijing social enterprise called Smart Air, and They make very simple but effective air purifiers by strapping a HEPA filter on to a fan. See the above links for details and all the research and tests they have performed. We are quite happy with our 2 Smart Air air purifiers (one "Original" and on "Cannon" and they do the job for our whole house up to around 250 µg/m³ outside levels. Above that they don't quite keep up. The only issue we have with them is that they are loud, especially the "Cannon" when run at maximum. 

Here is our Cannon in its out of the way location under a table in our entrance/kitchen area:

According to Smart Air, this fan on high speed puts out 56 dB of sound volume measured from 1.95 meters. It's loud (but apparently not louder than some of the commercial products costing 10 times as much). We are still waiting for Smart Air to release their quieter system that has been promised for a while now. I hear it is still under development and coming soon... In the meantime I decided to take matters into my own hands to see if we could make our Cannon quiet enough to not interfere with our sleep at night.

I started by measuring the sound levels of our Cannon:

I don't have a fancy decibel meter like Thomas at Smart Air used, but I have a cell phone which has a microphone and lots of processing power and of course one can get apps for everything these days. This is the app I found:
I don't expect that using this generic app on my cell phone will produce test results equal to an instrument designed for the job and calibrated against known sound levels, but I do expect it to give me reasonable data comparing one sound to another. You can see the tape measure in the above sound test photo, I made sure I was exactly one meter away from the fan for each test. This test showed that the ambient sound in the room was 30db and the Cannon on full speed fluctuated between 59 and 60 dB (so I'll call it 59.5 dB) 

We had some pieces of puzzle shaped soft plastic floor mat left over from another project so I quickly snapped a few of them together into a box to surround the Cannon:

This is not the thin stuff you see at every children's playthings store, what we have is a full 1 inch (2.5 cm) thick. Anyway, I tested the sound level of the canon on high inside this box to be 55.5 dB. wow a 4 dB drop, definitely worth cutting up the floor mats to make the box properly. I had to leave an opening front and back of course to let air through, so I made the top front stick out so I could hang a blanket over it without completely covering the hole:

It turned out that how I was measuring sound from the side of the Cannon, it made no difference to have the blanket on or off, but measured from the front, there was a 2 dB difference (55 with and 57 without the blanket).

There was a problem with my quick test - when I put my hand in front of the opening I could feel no airflow. I'm guessing a lot of the air is just circulating around inside the box. So I figured we needed a baffle inside the box to separate the front from the back. I made up a quick template out of cardboard before attempting to cut one out of a floor pad:

It fit fairly well and probably would have been good enough, but we had extra floor pads so I thought it would be a bit more stable for long term use to make it with the floor pad. This and the final cutting of the front and back sections meant getting out some fancy tools. fortunately we had the tools required in our kitchen drawer:

And here's the completed baffle:

View from the back with baffled installed:

View from the front:

Well, as long as we're going this far, why not through some padding into the box to further baffle the sound, so I added some old blankets and towels. Not sure how much of a difference they'll make but lets try it anyway:

As for the openings front and back, the Cannon has a diameter of 10 inches which makes an area of  79 in². I made opening of 4 inches front and back which, with the width of the box being 22 inches gives us an area of 88 in². This box should not be restricting the airflow in any significant way. I would have been confortable with an opening of 3.5 inches (77 in²) but then I could't reach my arm in to change the speed setting dial.

Finally, I used one of the cutoff's from the front and back opening to make and extension for the top so it can extend forward to let a blanket drape over it. 

And here is the finished box from the front. Obviously I'll have to pull the top off to change the filter but that only happens every 3 or 4 months. Oh, and yes, now with the divider in the middle, I can feel air blowing out the front.

and from the back:

And it is now much bigger but it still fits under our table:

Drum roll... the final sound test results: 53.5 dB for a full 6 dB drop compared to the naked Cannon. Wow, that is even better than I had expected based on the initial test run:

Now, with this finished product, testing the sound from the front with the blanket on and off shows no difference whatsoever on the meter. To the ear, there is a different quality of sound but the meter detects the same sound pressure.

We are thrilled with the results. The Cannon is now at a very comfortable sound level, easy to live with. We hardly even notice it set to medium all day long Additionally, under heavy pollution conditions, we find it acceptable to run full power. And on low power, it is so quiet as to be almost negligible, even for sleeping. We are definitely breathing cleaner air now at home because we are not turning off the fans all the time. Yes we are happy:

And now, if you have managed to stay with this report this far, then you might even be interested in all the sound data that I recorded. So here it is: