Archive for January, 2012

No, they weren’t dinosaurs. True, model sets of extinct animals often include saber-tooth cats, sail-backs (which were mammal-like reptiles and more closely related to us than to dinosaurs) and extinct marine reptiles as well as pterosaurs, but none of these are actually dinosaurs. Pterosaurs did, however, live alongside dinosaurs and are of great interest as the largest animals ever to fly on their own.

This DVD, another of the National Geographic series, looks at the mystery of pterosaur flight. As usual, the animation is not very exciting, but the scientific work and the attempt to build a mechanical pterosaur more than makes up for that.

The big questions are, how large did pterosaurs grow and how did they fly?

One of the threads of the program is the rather controversial discoveries of trackways and fossils suggesting even larger pterosaurs than Quetzalcoatlus, which itself had a wingspan of 10 meters (33 feet.) That’s three times larger than an albatross, the largest flying bird alive today. Forget the giants; how did even the ones we’re reasonably sure of fly?

The meat of the DVD, as far as I was concerned, was an attempt to build a robotic pterosaur, controlled like a model airplane. The result was not wholly successful, but a great deal was demonstrated about pterosaurs in the process.

First, pterosaur wings were a good deal more complicated than the sailcloth that was first tried. They had oriented stiffening fibers, muscles within the wing membrane, a good blood supply to the wings, a furry covering that (like the dimples on a golf ball) helped aerodynamically, and some kind of built-in sunscreen. (Bats are nocturnal in part because their wings would sunburn too badly in daylight.)

Control was incredibly sophisticated, certainly more so than could be mimicked by a model airplane controller. Much of the maneuvering of a real pterosaur was probably as automatic as keeping your balance is to you – possibly more so, if the speculation that baby pterosaurs were born knowing how to fly is correct. Changing the shape of the wings and the tilt of the head would have been automatic for a real pterosaur. Not so for the model, and it is hardly surprising that it was not fully successful, even aside from the problems of finding components and power sources of sufficiently light weight. Pterosaurs, like birds, had very light bone structures.

As entertainment this DVD falls short. But as documentation of a fascinating experiment, it is worth watching.

Sunrise this morning will be at 9:44 and sunset this afternoonat 4:22 for 6 hours 41 minutes of daylight. The sun’s high enough now – 7.6° — to shine in the south window for a couple of hours a day, but the shadows on the inside wall of the house were pretty blurred yesterday, thanks to ice fog in my yard. I was going to go into town Saturday, but we’ve had temperatures below 40 below since Friday afternoon. That means ice fog, with visibility zero in places (such as the highway between where I live and downtown) so I’ve stayed home

There is supposed to be a warming trend today, though there’s nothing as warm as 0°F in sight. I’ll believe it when I see it. I certainly hope I can get into town and do some much-needed shopping today.

Indoors, the Christmas cactus looks ready to bloom, so the cooler temperatures and/or the short days did their work. The sunquat, though blooming, is not setting fruit. Too cool, perhaps? Given that most of the plants would be happy a little warmer, I’ve set the plant room thermostat up a little, and the light timer back to longer days. I am definitely looking forward to summer outdoors!

Update: as of 8:45 AM, the indoor-outdoor thermometer, which has been stuck at LL all weekend, is reading -32°F and the dense fog warning has been cancelled. Maybe I’ll get that shopping done today. On the down side, the main plant room lights seem to have quit.

Six Sentence Sunday

It’s Sunday again, and I’m still posting consecutive bits from the second chapter of Rescue Operation (working title.) Tod’s the youngest of a group of teenaged “freedom fighters” who’ve been captured by slavers. To look at previous snippets, go to the index page (at the top) and click on “Six Sentence Sunday.” There you will find all of my SSS posts, listed by date and source.

Then [Tod] pricked up his ears as the conversation turned to getting them all into the transport.

Tod had hoped their captors would unfasten their shackles or at least release them from the cable, but it sounded like they planned to winch the whole cable into the transport.  The slavers’ concern was strictly over whether they’d all fit.  “We could take the girl in the flyer,” one of the men suggested, and Tod was instantly alert.  The best route to the flyer passed close to the cable, and yes, one of the smaller men was unfastening Tammy’s shackles from the cable and using a shoulder hold to push her along the cable toward Tod.

Tod shifted from side to side, trying to get slack in the cable.

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Why do plumes flatten?

Sometime the plumes from smokestacks just keep gong up until they disappear, but at other times they will stop and start spreading out once they have reached a specific height. Why?

One common explanation is that the plumes have reached a capping inversion and can’t go any higher. There is some truth in this, but it is a major oversimplification. Inversions aren’t something you reach, for one thing. Here in Fairbanks, and throughout the country at night, inversions often start at the ground. Further, they may extend for a considerable distance – up to a mile or more – vertically.

So just what is an inversion?

Under normal circumstances the air gets colder with height. One reason is that air cools as it rises. This is due to conservation of energy: the air is essentially swapping heat for potential energy. For dry air, the cooling rate is about 1°C per hundred meters, or 5.4°F per thousand feet. This is called the adiabatic lapse rate. When water is condensing, such as in a cloud, the air doesn’t cool quite as fast as it rises, because the condensing water adds heat to the air.

In an inversion layer, the air gets warmer with height. The rise can be only a degree or two occurring over a height of a few tens of feet, or it can be up to 20°C or more extending for a kilometer or two. But it is a layer of finite thickness, not just a flat plane at a specific height.

Here in Fairbanks, power plant plumes are generally visible because they contain water, which at low temperatures condenses. As a result it is very obvious when they reach a particular height and suddenly flatten out. But why?

They rise to start with because they are warmer than the surrounding air. They stop rising at the height where their temperature is the same as that of the air around them.

Part of this is because they cool as they rise. But if this were all that were involved, they would rise quite a long way. Suppose the plume temperature when it left the stack were 100°C – the boiling point of water. If it were simply cooling off at the adiabatic rate, it would take 10 kilometers just to reach the freezing point – and I guarantee that the air at 10 kilometers over Fairbanks in the winter never gets that warm.

So why do they flatten out and stop rising?

Because all the time they are rising, they are mixing with the surrounding air. This is actually visible in the photograph – the plume gets wider with height, due to the mixing in of cold environmental air. This works even for very small plumes. I have seen diesel trucks with stacks trailing a plume that flattens only a foot or two above the top of the stack, or stationary sources whose plumes flatten several hundred meters up. It’s a question of how fast the environmental air mixes with the plume as well as the initial plume temperature.

So if you see a plume flatten out, you can be pretty sure it is in an inversion, but not that there is a particular inversion at that particular height.

Day 712

Well, I am alone again – alone as I have not been, except for a few days, since I rescued Songbird. The nomads left this morning. I teleported to their camp to see them off, and even accompanied them for the first hour or so. But by then my feet were starting to protest, and I bade them a good journey and joy at the Gather and teleported back to the shelter.

Are my feet so different from theirs? They look the same, except that Songbird has calluses on her feet that are thicker than the soles on the remains of my ship shoes. I don’t think she was born with them; a baby was born this summer and her feet looked like normal baby feet. Perhaps they grow extra skin thickness on their feet, just as I grow replacement teeth?

My feet burn on the sand, are cut and bruised by the rocks, and blister when I try to improvise something approximating shoes. In general I find it quite impossible to walk without injury. They walk and run everywhere, feet bare of any protection, without even thinking about it.

I helped them on a few hunts – not by hunting myself, but by teleporting to several points in the area and then telling them where I saw game. I’m also good at spotting the weakest animal in a herd, and Patches is good at turning back animals that are trying to escape, and even better at tracking injured animals. In return – or as an act of worship – they have presented me with several beautifully tanned hides, including one from a buffalo that is quite thick. Perhaps I could try again to make some kind of sandals? They would not be as good protection as the boots my people made for hiking, but at least they would protect my feet from heat and cuts. And making them would be something to do.

This year the nomads stayed a hundred thirty-five days. I think the year is around three hundred sixty-five days, give or take a few days, so they should be back in about two hundred and thirty days. It is going to be a long time with only Patches for company.

I started posting on Six Sentence Sunday June 11, 2011 and  posted just about every Sunday until the end of Six Sentence Sunday January 27, 2013. Following that, I began posting in Weekend Writing Warriors, Snippet Sunday and most recently in Science Fiction Romance Brigade.  Here are the links to the excerpts I’ve posted. I’ve added a few to other excerpts from my writing.

Six Sentence Sunday logo

Tourist Trap riding scene 6/11/11
Tourist Trap dogs 6/19/11
Tourist Trap blizzard 6/26/11
Tourist Trap ski race 7/3/11
Tourist Trap sailboat 7/10/11
Tourist Trap start scene with Amber 7/17/11
Tourist Trap 7/24/11
Tourist Trap 7/31/11
Tourist Trap 8/7/11
Tourist Trap 8/13/11
Tourist Trap 8/21/11
Tourist Trap 8/28/11
Tourist Trap 9/4/11
Tourist Trap 9/11/11
Tourist Trap end of scene with Amber 9/18/11
Rescue Operation start of scene of Tod’s capture 9/25/11
Rescue Operation 10/2/11
Rescue Operation 10/9/11
Rescue Operation 10/16/11
Rescue Operation 10/23/11
Rescue Operation 10/30/11
Rescue Operation 11/6/11
Rescue Operation 11/13/11
Rescue Operation 11/20/11
Rescue Operation 11/27/11
Rescue Operation 12/4/11
Rescue Operation 12/11/11
Rescue Operation 12/18/11
Homecoming 12/25/11
Rescue Operation 1/1/12
Rescue Operation 1/8/12
Rescue Operation 1/15/12
Rescue Operation 1/22/12
Rescue Operation 1/29/12
Rescue Operation end scene of Tod’s capture 2/5/12
Rescue Operation Ch 1 2/12/12
Rescue Operation Ch 1 2/19/12
Rescue Operation Ch 1 2/26/12
Rescue Operation Ch 1 3/4/12
Rescue Operation Ch 1 3/11/12
Rescue Operation Ch 1 3/18/12
Rescue Operation Ch 1 3/25/12
Rescue Operation Ch 1 4/1/12
Rescue Operation Ch 1 4/8/12
Tourist Trap Zhaim 4/15/12
Tourist Trap fight 4/22/12
Tourist Trap Control 4/29/12
Tourist Trap Beating end 5/6/12
Tourist Trap Zhaim 5/13/12
Tourist Trap Zhaim 5/20/12
War’s End 5/27/12
War’s End 6/3/12
War’s End 6/10/12
War’s End 6/17/12
War’s End 6/24/12
War’s End 7/1/12
War’s End 7/8/12
War’s End 7/15/12
War’s End 7/22/12
War’s End 7/29/12
War’s End 8/5/12
War’s End 8/12/12
War’s End 8/19/12
War’s End 8/26/12
Who’s Bounce? 8/30/12
War’s End 9/2/12
War’s End 9/9/12
War’s End 9/16/12
War’s End 9/23/12
War’s End 9/30/12
War’s End 10/7/12
More on Pocket Herders 10/10/12
War’s End 10/14/12
War’s End 10/21/12
War’s End 10/28/12
War’s End 11/4/12
War’s End 11/11/12
War’s End 11/18/12
War’s End 11/25/12
War’s End 12/2/12
War’s End 12/9/12
War’s End 12/16/12
War’s End 12/23/12
War’s End 12/30/12
War’s End 1/6/13
War’s End 1/13/13
Horse Power  1/20/13
War’s End 1/27/13

WWW logo rect
War’s End 2/3/13
War’s End 2/10/13
Year of the Snake (War’s End) 2/10/13
War’s End 2/17/13
War’s End 2/24/13
War’s End 3/3/13
War’s End 3/10/13
Horse Power 3/17/13
War’s End 3/24/13
War’s End 3/31/13
War’s End 4/7/13
War’s End 4/14/13
War’s End 4/21/13
War’s End 4/28/13
War’s End 5/5/13
War’s End 5/12/13
War’s End 5/19/13
War’s End 5/26/13
War’s End 6/2/13
War’s End 6/9/13
Horse Power 6/16/13
War’s End 6/23/13
War’s End 6/30/13
Horse Power 7/7/13
War’s End (final) 7/14/13
Homecoming 7/21/13
Tourist Trap 7/28/13
Horse Power 8/4/13
Homecoming 8/11/13
Tourist Trap 8/18/13
Horse Power 8/25/13
Homecoming 9/1/13
Tourist Trap 9/8/13
Horse Power 9/15/13
Homecoming 9/22/13
Horse Power 9/29/13
Tourist Trap 10/6/13
Homecoming 10/13/13
Homecoming 10/20/13
Homecoming 10/27/13
Homecoming 11/3/13
Homecoming 11/10/13
Homecoming 11/17/13
Homecoming 11/24/13
Homecoming 12/1/13
Homecoming 12/8/13
Tourist Trap 12/15/13
Homecoming 12/22/13
Homecoming 12/29/13
Homecoming 1/5/14
Tourist Trap 1/12/14
Tourist Trap 1/19/14
Tourist Trap 1/26/14
Tourist Trap 2/2/14
Tourist Trap 2/9/14
Tourist Trap 2/16/14
Tourist Trap 2/23/14
Tourist Trap 3/2/14
Tourist Trap 3/9/14
Tourist Trap 3/16/14
Tourist Trap 3/23/14
Tourist Trap 3/30/14
Tourist Trap 4/6/14
Tourist Trap 4/13/14
Tourist Trap 4/20/14
Tourist Trap 4/27/14
Tourist Trap 5/4/14
Tourist Trap 5/11/14
Tourist Trap 5/18/14
Tourist Trap 5/25/14
Tourist Trap 6/1/14
Rescue Operation 6/8/14
Rescue Operation 6/15/14
Rescue Operation 6/22/14
Rescue Operation 6/29/14
Rescue Operation 7/6/14
Rescue Operation 7/13/14
Rescue Operation 7/20/14
Rescue Operation 7/27/14
Rescue Operation 8/3/14
Rescue Operation 8/10/14
Rescue Operation 8/17/14
Rescue Operation 8/24/14
Rescue Operation 8/31/14
Rescue Operation 9/7/14
Rescue Operation 9/14/14
Rescue Operation 9/21/14
Rescue Operation 9/28/14
Rescue Operation 10/5/14 (Published late.)
Rescue Operation 10/12/14
Rescue Operation 10/19/14
Rescue Operation 10/26/14
Rescue Operation 11/2/14
Rescue Operation 11/9/14

SFR Presents logo
Both Sides Now 2/14/14
Both Sides Now 2/21/14
Both Sides Now 2/28/14
Homecoming 3/8/14
Homecoming 3/22/14
Homecoming 3/29/14
Tourist Trap 4/5/14
Both Sides Now 4/12/14
Both Sides Now 4/19/14
Rescue Operation 4/26/14
Both Sides Now 5/3/14
Both Sides Now 5/10/14
Both Sides Now 5/17/14
Both Sides Now 5/24/14
Both Sides Now 5/31/14
Both Sides Now 6/7/14
Both Sides Now 7/5/14
Both Sides Now 7/12/14
Both Sides Now 7/19/14
Both Sides Now 7/26/14
Both Sides Now 8/2/14
Both Sides Now 8/9/14
Both Sides Now 8/16/14
Both Sides Now 8/23/14
Both Sides Now 8/30/14
Both Sides Now 9/6/14
Both Sides Now 9/13/14
Both Sides Now 9/20/14
Both Sides Now 9/27/14
Both Sides Now 10/2/14
Both Sides Now 11/6/14

Quotes from Mercedes Lackey

More quotes from Storm Breaking, by Mercedes Lackey. The first two are a continuation of the Shin’a’in proverbs bombarding Karal.

“Never sit down to eat with your sword at your side.”

“Better an honest enemy than a feigned friend.”

“Who is wisest, says least.” Karal finally manages to interrupt the leshy’a Kal’enedral’s proverbs.

“Despair was an emotion for weaklings or failures.” Emperor Charliss, as he sees his empire crumbling around him.

“The best plans never survive the first engagement with the enemy.” Darkwind, thinking of a Shin’a’in proverb and wondering how the Eastern Empire has survived so long when it insists on having plans for everything.

“As with cards, duels and death sports, look at the odds — but consider the stakes.” Melles, considering how to gain control of the Empire.

“Having power and not using it was a form of weakness.” Sue Ann Bowling, Homecoming. Part of Zhaim’s philosophy of life, but it would fit Charliss just as well.

Every now and then I order a course on DVDs from The Great Courses. Most recently, I’ve been viewing Skywatching, a course by Alex Fippenkio on the sky, day and night: what can be seen in it and the physics of why it looks the way it does.

Roughly the first third of the course deals with what we can see in the daytime sky. Dr. Filippenko discusses sky color in midday and when the sun is rising or setting, clouds, lightning, and the interaction of sunlight with water and ice (giving rainbows and halos.) This is closely related to what I researched and taught, so I didn’t really lean anything new. The presentation, however, was generally good. I did catch an error in one diagram, but I suspect that was the graphic designer. (The diagram is the one used to explain polarization in reflected light, and the error is that the angle of reflection and the angle of incidence are not shown as equal.) I was also rather disappointed that Dr Filippenko did not point out that frozen droplets are initially near-spherical, and develop their hexagonal prism shape (and the optical effects this produces) only later, by vapor-phase growth. But I suppose I shouldn’t expect everyone to be familiar with ice fog.

This section of the course should be of particular interest to writers needing information on sky and cloud cover, storms, and less common phenomena such as rainbows or sundogs. If you are going to describe an evening sky, you’d better have some idea of what’s happening.

Roughly half the course deals with the constellations and observing the bodies of the solar system. Most of this I was familiar with as an amateur, and I’ve used some of it — lunar phases and seasons, for instance — in my writing. Every writer who wants to put a moon in the sky should watch the section on lunar phases. Rising crescent moon in the evening? Nope. Just doesn’t happen. Neither does a narrow crescent high in the sky.

The lecture on solar eclipses brought back the one I saw, shortly after I moved to Alaska in 1963. I didn’t have a car yet, but two other graduate students gave me a ride down to Sourdough, Alaska to see the total solar eclipse of July 20, 1963. There were scattered high clouds, and while they added suspense –would the sky be clear during totality? – they wound up adding to the experience. Every bright spot of Bailey’s Beads had its own rainbow (technically iridescence.) I know I took a picture; I remember taking photos both before and after the eclipse, the ones after being a series with the exposure set at a constant value to capture the change in the light. I found that series, but so far the ones before and during totality are missing. They may have been separate from the others and lost during the fire twelve years ago.

Overall I’d give the course an A. Dr. Filippenko is a wonderful teacher, and with few exceptions the graphics are excellent. The course takes 3 DVDs and consists of 12 45-minute lectures.

The sun will rise this morning at 10:05 and set at 4:01 pm for a whole 5 hours 55 minutes of daylight. We’re gaining more than 6 minutes a day, now, and the sun is almost 6° above the horizon at noon. It was actually shining through the south window Friday, casting the shadow of the suncatcher on the north wall. It warmed up almost to 0°F last week, but it isn’t forecast to last. No more snow to speak of, though.

Driving is miserable, especially heading south into the low sun. At least the light now lasts long enough I can get some shopping done as well as getting the plastics and paper in to the recycling center.

No, we don’t have trash pickup here. Once a week I put the week’s trash into the car and haul it to the transfer station, which is a huge battery of dumpsters plus a recycling platform for things people might be able to reuse – furniture, clothes, toys – in fact, just about everything. This is supposed to discourage dumpster diving. It doesn’t.

Some things, such as plastic bottles, paper and cardboard, can be turned in for recycling at the Rescue Mission, and the University students recycle glass. So I generally have a pretty full car going into town Saturday.

The short light cycle and the lowered temperature in the plant room have worked their magic on the Christmas cactus, which has two to three fat buds on every branch. And the first blooms have actually opened on the sunquat. It’s still winter here, with temperatures expected to stay well below zero for quite a while yet, but spring is on its way.

Six Sentence Sunday

It’s Sunday again, and I’m still posting consecutive bits from the second chapter of Rescue Operation (working title.) Tod’s the youngest of a group of teenaged “freedom fighters” who’ve been captured by slavers. To look at previous snippets, click “Six sentence Sunday” under the “Writing” tab.

[Tod] thought she had the better chance of getting away, and the last thing he wanted was for her to give up any chance she had by trying to rescue him.

She hesitated, studying her bonds, and then nodded slightly, reluctantly.

Their captors were talking now, discussing the weakened dam and how they’d reinforced it.  Something about being careful not to damage the infrastructure.  Worried about the dam, but not about the people?  That didn’t make sense to Tod.

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