• hard-wired, with
• battery backup, and
• interconnected

The batteries in battery-powered smoke alarms will run out. They do chirp to let us know it’s time to change the battery, but more often than not I won’t have a spare battery handy, or I won’t have a step stool nearby, or it will be the middle of the night, so instead of going back on the ceiling with a new battery like it’s supposed to, the alarm will sit around on a counter, battery-less, sometimes for weeks. Hard-wired smoke alarms solve the dead battery problem because they draw their power from the house electrical wiring. As it turns out, electrical fires that disrupt the power before smoke could be detected are really rare, and our power is pretty reliable, so the risk that the power’s off when the alarm needs to sound is really quite small, smaller than the risk that your battery-powered alarm will be sitting, battery-less, on the counter. And most hard-wired alarms also have battery backup, so you’re covered during power outages, too.

There are two smoke-detection technologies: ionization and photo-electric. Ionization sensors do well with small smoke particles, from fast-burning fires, while photoelectric sensors do better with large smoke particles from smoldering fires. Most safety recommendations (including Consumer Reports) are reluctant to specify one as being a better choice, and recommend both. So add to our wish-list:

• dual-sensor

Interconnection of smoke alarms means that when one alarm goes off, all of them sound. So if there’s a fire in the basement while you’re asleep, the alarm in your second-floor bedroom will also go off, giving you much more time to escape than waiting either for enough smoke to set off a second-floor alarm or for you to hear the far-away alarm. The interconnection is conventionally done with three-conductor wiring: all the smoke alarms need to be installed on the same circuit and the third wire is used as the alarm interconnection signal wire. This is easy in new construction but really hard to retrofit: getting a new circuit to the ceiling of every location for a smoke alarm would mean lots and lots of holes in the walls and ceilings.

So an easier method for retrofit has emerged: wireless interconnection. The smoke alarms can still be hard-wired, but can be on different circuits, typically extended from existing ceiling fixtures. Sounds great! Kidde and First Alert both manufacture such systems. But each offers only one sensor type! Kidde’s hardwired with wireless interconnect detector uses an ionization sensor; First Alert’s uses photoelectric.

So which to choose? Compulsive complete-ist that I am, I scoured the internet looking for advice comparing the two detection methods, and eventually came across the NIST report which I believe all other advice is based upon. Like everything else I found, it, too, doesn’t recommend one technology over the other, but by sifting through its data, I’ve concluded that I definitely want both sensor types in each room, even if that means installing two smoke alarms in each room.

The NIST tests set fires of several types (flaming, smoldering, cooking) in two settings: a trailer home and a two-story home (although one without soffits between the rooms and the hallways). They measured the time it took for alarms of different types to sound, and also the time between the alarm sounding and the moment at which escape becomes “untenable,” meaning that the smoke density had reached some critical level.

For flaming fires, what struck me was that the total time between the start of the fire and the onset of untenable escape conditions was between 150 and 400 seconds. Ionization detectors sounded 24 to 64 seconds earlier than photoelectric, which is a significant amount of time on the time scale of flaming fires. Other research cited by NIST indicates that it can take the average person 50 seconds to actually exit a house, taking time to put on a bathrobe, grab wallet and keys, wake children up, and so forth. 

What isn’t said, but can be inferred, is that interconnected ionization detectors give the best and likely only chance to rescue, say, a child, from a bedroom in which the fire starts. The times to untenability only refer to the escape of people who aren’t in the same room as the fire. Fire codes “are not designed to protect people intimate with the initial fire;” survival in the same room as the fire is an entirely separate, more complicated, and controversial topic. But needless to say, every second would count in such a situation, thus the extra speed of an ionization detector in the afflicted room, plus interconnection to immediately let everyone else in the whole house know, would give as many extra seconds as possible.

So we know we want ionization detectors. What about photoelectric? Well, the total times to untenability for smoldering fires fell between an hour and an hour and twenty minutes. In many cases, photoelectric detectors responded 15 minutes to an hour faster, time scales which are significant fractions of the fire time. Catching such a fire 15 minutes sooner could significantly reduce the damage done by a fire–it might even give enough time for a homeowner to take care of the fire with a fire extinguisher. The only instances when photoelectric detectors didn’t outperform ionization detectors for smoldering fires was when the detector and fire were far apart: a fire in a bedroom with its door closed, with the smoke alarm in the nearby hallway, or a living room fire with the alarm in the hallway. But if there was an alarm in the room in which a smoldering fire started, the photoelectric detector sounded significantly sooner.

So, for now, two alarms per room.

Of all the yuppie housewares catalogs, NapaStyle is one of the yuppiest, to the point of almost being a laughable self-parody. But I’m writing here about something I bought from them (a NapaStyle exlcusive, even) that’s turned out to be quite a satisfying purchase: the Stemware & Plastic Baggie Dryer. I hate to throw away plastic Zip-Lock bags after just one use; far better to wash and re-use them. This device is a ring of eight wood rods that make excellent places to hang plastic baggies to dry.

Of course, one doesn’t need a drying rack to wash and re-use plastic baggies, but I wasn’t regularly doing so until I bought this drying rack. The drying rack works very well for its task. It’s also a very unassuming product: it does not need to have its own box: it was simply placed inside the shipping box. It was not enclosed in a plastic bag, it was not packed with custom-fit styrofoam. It was not tied to a piece of cardboard with twist-ties. It required no assembly. It came with no manual, no marketing survey disguised as a warranty card, and no safety warnings. It has no website. You can’t get on it’s email list for exciting product updates. It’s made almost entirely of wood. It was made in Canada. 

I wish more products were like that.

Release dates of versions of Mathematica

Mathematica 6 was a substantial upgrade: the graphics system was completely overhauled, the curated data, that I’ve used as the basis for some posts here, was added, and the ability for dynamic interactivity was added with Manipulate and Dynamic. 

I am not, of course, a major Mathematica user. In fact, although I’m a physicist, I haven’t made tremendously much use of Mathematica for my professional work. This is partly because I tend to deal with relatively small data sets, for which a GUI-based data analysis tool is usually easier to work with than the command-line Mathematica. And I’d consider myself an advanced user of Pro Fit, the data analysis tool that’s made all the graphs for all the work I’ve done since about 1998.

In fact, my Mathematica license is my own personal one. As a graduate student, I bought the Student version of Mathematica, which they allow you to upgrade to a full professional license for only a few hundred dollars, compared to the $2500 list price of a new professional license.

Wolfram really wants its users to buy Premier Service, a several hundred dollars per year service which entitles you to all upgrades, major and minor. If you don’t buy premier service, then you need to pay for all upgrades, even the N.M.X to N.M.X+1 minor bug-fixing upgrades. And without premier service, you’re not even supposed to install Mathematica on more than one computer. Draconian and greedy, if you ask me, but they can do that, because they’re Wolfram. And for tech-heavy firms that make heavy use of Mathematica and get millions of dollars worth of value from whatever they compute in Mathematica, it makes sense. But it makes it very difficult to be a casual user.

And even though your existing copy can do everything it could the day you bought it, once the difference between your copy and the current release gets large enough, there is no longer an upgrade path. I think this is one of the motivations to release this as version 7 and not 6.1: I don’t recall the precise figure, but Wolfram generally offers an upgrade path only for jumps smaller than 1.5. If this is still the case,² what this does is cut off anyone who hadn’t upgraded to version 6. Update: enough with the conspiracy theories! Wolfram clears up the upgrade policy in the comments.

In my case, with Version 6.0.1, I have a choice of paying $750, and getting a year of Premier Service, or paying $500 for just version 7.0.0 with no service. Out of my own pocket, ouch! But what makes it really enticing, for me, is that Mathematica now reads SHP files. These are the Geographic Information System data files, promulgated by ESRI, in which vector-valued geographic data is commonly exchanged. In particular, the DC Office of Planning makes an amazingly large collection of DC GIS data available in SHP format. The possibility for quantitative analysis of DC mapping data is very tantalizing.

Of course, Wolfram wouldn’t release a major number upgrade without hundreds of other new features. As of yet, there isn’t much substantial written about version 7. I did find some notes from a beta-tester and from a college math teacher. I’ll probably buy it, even though it would mean delaying other expensive toys that I want.

1. most of the dates come from the Wolfram News Archive, some from the Mathematica scrapbook pages
2. I’ve asked Wolfram, but haven’t received a reply.

I actually don’t talk to many telemarketers anymore–I’m on the do not call list, so nobody’s been calling to sell me aluminum siding or vacation get-aways. Ever since cell phones really took off, it seems that the long distance companies aren’t falling over themselves to get you to switch to their plan, although I do remember plenty of this in the late 90’s. And although we don’t have caller ID, we’ve gotten pretty good about catching the second or so delay from the robodialers and hang up before the telemarketer comes online.

But sometimes someone does get through, and it’s usually either a charity (usually one that I nominally support) or a political campaign, asking for more money. However, I really, strongly prefer to give on my own terms and on my own schedule, and not theirs. So I want to get rid of them, in some way that’s still polite. So this is what I say now:

Although I will continue to support [your cause], I do not make financial commitments over the phone due to identity theft concerns.

All I have to do now is think of a line to get rid of the (overpriced) identity theft “protection” sales pitches that my credit card companies foist upon me.

But I realized that this sort of comparison is something that Mathematica 6 is supposed to be good at. Mathematica is an amazingly powerful system for doing mathematics on a computer. Its strength, traditionally, has been symbolic manipulation–I most often use it for the Integrate command, which can do most of the integrals that in grad school I’d look up in Gradshteyn and Ryzhik. Version 6 has added, amongst other things, a huge library of curated data, loaded over the Internet, that’s relatively straightforward to use.

The command CountryData gives access to all sorts of country-by-country information, including “GDP” and “GovernmentDebt”. So following one of the examples in the documentation, I produced this graph, plotting the Debt-to-GDP ratio versus GDP for (nearly) all the countries for which Mathematica has data. (Note that the x-axis is a logarithmic scale.) The United States, before and after a $700 billion bailout, are shown in green and red, respectively.

If the xhtml export actually works the way it’s supposed to, you should be able to hover your mouse cursor over each point and have a little ToolTip pop up telling you which country the data are for.

GDP [$US]

Mathematica has a syntax that strikes many as arcane. Since I learned about computers with procedural programming, and haven’t really done any functional programming, I too struggle to get Mathematica to do what I want it to do. But one can often do complicated things, such as the above graph, with a very compact command. To make the main graph–the red and green dots are relatively trivial additions–the command I used is:


gdpplot =
ListLogLinearPlot[
Tooltip[{CountryData[#, "GDP"],
CountryData[#, "GovernmentDebt"]/CountryData[#, "GDP"]},
CountryData[#, "Name"]] & /@ CountryData["Countries"],
PlotRange -> {{10^9, 2 10^13}, {0, 2}}]


There are a couple things one needs to understand for this to make sense: First is Mathematica’s syntax for pure functions, using all the stuff with the #s and up through the &. Second, the /@ is shorthand for the Map command, which means apply the function on the left to each element of the list on the right. Finally, the command CountryData["Countries"] produces a list of all the countries for which Mathematica has data.

1. He is, nevertheless, against the bailout.

I came across it via a 3 quarks daily item referencing a New York Times article. That I discovered this two-week old clip–which already has millions of views–so circuitously speaks to the fact that I’m just not up on what’s hot on the Internets these days. 

Any number of descriptors come to mind for this video: goofy, joyful, callow, spontaneous, kitschy, universalistic. One could ask what sort of manipulation is going on when upbeat music makes you feel upbeat. One could find any number of reasons to by cynically dismissive of the whole thing–perhaps by counting up the ways it could illustrate Stuff White People Like. That might have been my reaction, some years ago.

But watching the video did bring me a few minutes of joy today. Upon reflection, it brought to mind the “Dancing in the Street” pattern (#63) from A Pattern Language:

All over the earth, people once danced in the streets; in theater, song, and natural speech, “dancing in the street” is an image of supreme joy. Many cultures still have some version of this activity… 

But in those parts of the world that have become “modern” and technically sophisticated, this experience has died. Communities are fragmented; people are uncomfortable in the streets, afraid with one another; not many people play the right kind of music; people are embarrassed….

The embarrassment and the alienation are recent developments, blocking a more basic need. And as we get in touch with these needs, things start to happen. People remember how to dance; everyone takes up an instrument; many hundreds form little bands.

APL goes on to with recommendations for building an environment that fosters dancing in the street. So however accidentally and undeliberately he got into it, Matt Harding is onto something.

The video clip above is the third of his videos. The second video, from 2006, is similar, but consists mostly of Matt dancing by himself. In fact, it was the spontaneous participation of the children in Rwanda that led, in part, to the idea for the third video. The second video is set to a song called “Sweet Lullaby,” by Deep Forest. Watching the video, the song struck me as quite familiar. Was it from an ad? From This American Life? I was having the hardest time placing it, until I realized that it was actually a track on a Lullaby CD of ours.

Bittman’s talk from the TED (=Technology, Entertainment, Design) conference is now online. In 18 minutes–the length of all TED talks–he examines the ways in which the industrialization of food, particularly livestock, has been a disaster for the environment and our health. Also see his January New York Times article, which discusses the same ideas.

(via 3 quarks daily.)

I chose two different styles: the first, which I ordered from eInvite, are simple: the domain name, my name, and my email address. They had sufficiently robust online design tools so that I could get the type of card I had imagined without worry that fonts wouldn’t be imbedded or that some other problem associated with emailing a PDF wouldn’t happen. And I am quite pleased with the cards.

The second ones were photo cards, to promote the Matthew Picture of the Day. I wanted full-color photos on these, with the website url. For these, I went with Moo’s mini-cards, which seem to be the favorite of hipster digital designer types. These, too, came out well. 

I got 100 of each, which for business-size cards is a small order. But I’d like to compare the packaging that each company sent my cards in.

First, the photo mini-cards. One hundred of them, in a small box, in a modest padded envelope:

The standard cards came in a corrugated cardboard box, half of which was taken up by packing material and the other half of which contained a smaller box: 

Opening the smaller box revealed a fractal-like pattern: half of the smaller box was taken up by packing material, and half contained a smaller box:

Inside this third box were, finally, the cards. But half of the inside of the third box was also taken up by packing material:

To illustrate the amount of empty space that was shipped to me, here are the cards shown inside the outer-most shipping box:

Michael Pollan’s Why Bother?, from last Sunday’s New York Times Magazine, opens by recounting what for Pollan was the “most upsetting moment” of An Inconvenient Truth: the “immense disproportion between the magnitude of the problem Gore had described and the puniness of what he was asking us to do about it.” Pollan defends notions of virtue and the steps, particularly gardening, that individuals might take to reduce their individual carbon footprints, vis-à-vis other responses to the climate crisis such as hopingfor some future technology. He writes: “Cheap energy, which gives us climate change, fosters precisely the mentality that makes dealing with climate change in our own lives seem impossibly difficult…. Al Gore asks us to change the light bulbs because he probably can’t imagine us doing anything much more challenging, like, say, growing some portion of our own food.”

Second, the April 12th Sierra Club Radio podcast has a segment with Bob Schildgen—Mr. Green—promoting his new book, which compiles questions and answers from his column in Sierra magazine. On the question of paper vs plastic (his answer–neither; bring your own bag), he encourages listeners to put things into perspective by mentioning that you likely burn as much petroleum in one trip to the grocery store as it takes to make all the plastic bags you’d use in a whole year. I can’t find his numbers online, but using the figures I wrote about earlier: 330 bags per American per year, 200 bags per gallon, so just over one and a half gallons of oil per American devoted to plastic bags. At 20 miles per gallon, you could make a round trip to a supermarket 15 miles away. Right order of magnitude, but I think you could travel a bit farther on that amount of gas.

This exercise in scale is then thrown out the window later in the interview, when host Orli Cotel asks the heavily loaded question: “For our listners who do own cars or need cars for whatever reason, what tips can you give us, as Mr. Green, to help reduce the amount of gas that we’re using,  besides of course cutting back on car travel?” (As if there’s some secret, magic way to drive without using gas that only the hardcore enviros know about.) Mr. Green goes on to mention that Americans lose about 4 million gallons of gasoline per day because of underinflated tires. Of course, he doesn’t put this into perspective: that’s about 1% of our daily gasoline consumption; we burn through 4 million gallons of gasoline in about 15 minutes.

I’d long felt an uneasiness about the suburbs: I’d had a general notion that total reliance on cars must be bad for the environment, and I also knew that the suburbs appeared dull and boring at best, but I could never quite put a finger on precisely what was wrong with them. Kunstler’s book was a clarion illumination of the problems of suburbia; he put into amusingly acerbic words precisely what I had felt.

Kunstler wrote two more books about the built form: Home from Nowhere, and The City in Mind, and he maintains a curmudgeonly website, with his delightful eyesore of the month. Kunstler is, by trade, a writer, and so his work is generally very well crafted. In the past few years he has mostly been concerned with Peak Oil and the complete catastrophe it could be for the American Way of Life, and his book on the subject, The Long Emergency, isn’t quite as captivating as his other works: in large part because the depth of research and analysis that went into his other books just isn’t there.

As someone who listens to several podcasts, I was excited to learn that he is now doing a weekly podcast of his own: Kunstlercast. The first episode concerns (chain) drugstores, and their proliferation. It’s worth listening to.