Got a blogger in your life? Want to get them something new and fancy? Are you a blogger? Looking to see if the shiny iPad 2 does everything you need?
I don't have one, but my mom ended up getting one, so I spent some time yesterday checking out how easy it would be to use it as a Thurs-Demo tool. I did two tests. The first was pulling a full-size HD movie off my Canon 7D and processing it with the iPad. The second was a video shot with the iPad's video camera. Both of these were done with iMovie and were remarkably quick to make. The slowest part is the USB link between iPad and camera.
I would venture to say that the video quality off the iPad isn't bad. In places with lots of light, it's pretty clear and sharp. But in lower-light locations (indoors with curtains drawn), it's a bit grainy. And the resolution of the video is sufficient, but not so high resolution as to track individual drops of water or grains of sand...
I thought some of you might be interested - I know the most interesting thing about the iPad2 for me is the enhanced video capability. It's not something that would replace the high-end video capability I have with my Canon 7D and computer, but it would shorten the time required for some of the video work and it does create possibilities where none existed before.
Thursday, November 24, 2011
Sunday, November 20, 2011
Dune Week
Looks like folks are talking about sand dunes and eolian transport on the geoblogs this week.
Here's some video I shot of blowing sand - you can see at least two distinct modes of movement - large grains are either tumbling individually, or avalanching down the slip face. Smaller grains, however, are picked up by the wind and bouncing (saltating) as they are transported.
Here's some video I shot of blowing sand - you can see at least two distinct modes of movement - large grains are either tumbling individually, or avalanching down the slip face. Smaller grains, however, are picked up by the wind and bouncing (saltating) as they are transported.
Thursday, November 17, 2011
Hey Nature, Don Draper called - he wants his male privilege back
Wow, Nature's editors really served up a turd of a fiction article this time.
From what I've been able to tell, it's some kind of "story" about how women are from venus and men are the only ones who can observe the real world. I'm not going to dissect the piece. There are plenty of people that have done so with more wit and honesty than I could hope to achieve. Suffice to say, I found the "observations" by the so-called protagonist offensive. I feel very sorry for his wife (I assume he's married to one - or was), because she is apparently cursed for all time to be unaware of the concrete gender roles that surround us all. Then again, I buy my own clothes. I cook dinner. I also do science. Apparently the person in the story can't do any of these things - only make biased observations and purchase Jethro Tull albums.
It makes me sad. Not only because it really calls in to question the awareness of the editors at Nature. By association, does this article make any of the quality work published in Nature less good? I don't think so - but it does diminish the appeal of one of the most widely read and prestigious journals.
Which is sad in that it takes away from some really cool fiction published in the same venue. If you want to read something that sounds like an ad copy out of "Mad Men," go read Womenspace (whatever the hell that means).
If you want to read some good fiction in the Futures section of Nature magazine, go check out my pal Steph's story with a much more appealing title, "Here be Monsters."
From what I've been able to tell, it's some kind of "story" about how women are from venus and men are the only ones who can observe the real world. I'm not going to dissect the piece. There are plenty of people that have done so with more wit and honesty than I could hope to achieve. Suffice to say, I found the "observations" by the so-called protagonist offensive. I feel very sorry for his wife (I assume he's married to one - or was), because she is apparently cursed for all time to be unaware of the concrete gender roles that surround us all. Then again, I buy my own clothes. I cook dinner. I also do science. Apparently the person in the story can't do any of these things - only make biased observations and purchase Jethro Tull albums.
It makes me sad. Not only because it really calls in to question the awareness of the editors at Nature. By association, does this article make any of the quality work published in Nature less good? I don't think so - but it does diminish the appeal of one of the most widely read and prestigious journals.
Which is sad in that it takes away from some really cool fiction published in the same venue. If you want to read something that sounds like an ad copy out of "Mad Men," go read Womenspace (whatever the hell that means).
If you want to read some good fiction in the Futures section of Nature magazine, go check out my pal Steph's story with a much more appealing title, "Here be Monsters."
Sunday, November 13, 2011
Thurs-Demo: The One with (Specific) Gravity
This week's demo has been a little late in coming - but I've got a few moments to get this up. Video is still processing though...
The plastic media that comes with the Emriver stream table is made of ground-up plastic. The stream model's physical behavior is largely determined by the relative difference between the density of flowing water and the sediment (there's also the viscosity of water, but that's another set of posts).
The above graph shows my student's results from soil mechanics lab last week. Students' results (red points) are a bit more varied than mine (blue). Aside from one errant point, student results lie along, or to the left of my own results - this suggests to me that it's a measurement error, rather than very different material. The leftward distribution points to less water than expected, rather than more. This could be the result of letting too much water dribble down the side and not into the measuring container, or waiting for all the water to stop dripping out of the spout. Or that the coarser fraction doesn't displace water as easily as a more graded mixture. Still, for 10-15 minutes worth of lab work, not a bad set of data.
This graph shows the results from a more extended set of measurements. The lab had students using a small (~100ml) overflow beaker - small errors like missed drops end up having a very large effect. So I tried using a much larger overflow beaker. My results were very consistent (basically a SG of about 1.50 ±0.01). But these values are a bit lighter than what Steve Gough (head of the LRRD) had for their color-coded material at 1.7. It's possible that my method allows for too much material to cling to the top of the beaker. Or the air bubbles trapped next to the surface of the plastic result in lighter-than-actual measurements.
So why graph the data this way? I can measure the plastic media's mass very accurately. And the amount of water displaced is proportional to the specific gravity of the material. So by making a bunch of measurements of two values, I can define a third as a linear function of the other two. It also saves some time on the calculation side of things.
The plastic media that comes with the Emriver stream table is made of ground-up plastic. The stream model's physical behavior is largely determined by the relative difference between the density of flowing water and the sediment (there's also the viscosity of water, but that's another set of posts).
The above graph shows my student's results from soil mechanics lab last week. Students' results (red points) are a bit more varied than mine (blue). Aside from one errant point, student results lie along, or to the left of my own results - this suggests to me that it's a measurement error, rather than very different material. The leftward distribution points to less water than expected, rather than more. This could be the result of letting too much water dribble down the side and not into the measuring container, or waiting for all the water to stop dripping out of the spout. Or that the coarser fraction doesn't displace water as easily as a more graded mixture. Still, for 10-15 minutes worth of lab work, not a bad set of data.
This graph shows the results from a more extended set of measurements. The lab had students using a small (~100ml) overflow beaker - small errors like missed drops end up having a very large effect. So I tried using a much larger overflow beaker. My results were very consistent (basically a SG of about 1.50 ±0.01). But these values are a bit lighter than what Steve Gough (head of the LRRD) had for their color-coded material at 1.7. It's possible that my method allows for too much material to cling to the top of the beaker. Or the air bubbles trapped next to the surface of the plastic result in lighter-than-actual measurements.
So why graph the data this way? I can measure the plastic media's mass very accurately. And the amount of water displaced is proportional to the specific gravity of the material. So by making a bunch of measurements of two values, I can define a third as a linear function of the other two. It also saves some time on the calculation side of things.
Monday, November 07, 2011
Writing Challenge, Part the first
Anne Jefferson issued a challenge last week. She has some writing that needs to be done and to keep things motivated, she asked fellow geobloggers to join in and share their progress - and it seems that 41 folks joined in. The logo comes from Anne's fellow Allochthonian, Chris Rowan. I have two papers I'd like to finish this month, so I figure this will be a good kick in the pants.
What did I get done this week? Well, about the only thing I got done was some organization - I had a paper rejected (with the encouragement to resubmit) last month and I think the biggest thing to improve it will be to split it into two papers. Especially because the data I presented at GSA this last month ties into the part of the paper that deals with the fluvial chronology of the Upper Mississippi Valley. I've got most of the pieces for each paper, but many of them are out of place, or hanging out somewhere else. So I spent some time trying to figure out what needs to be where.
Aside from that, I taught classes, had my birthday, and then had to go to a wedding (where I got to see my new niece - she's very cute). So last week was a slow start. Not to worry - I have most of the figures in a near-final form already, over 5 pages of comments from the reviewers, and several pages worth of my own notes all ready dealt with.
This week, I would like to have all the pieces for the chronology paper in place (they don't need to be very pretty right now). Once I know how much I have to say for the methods, results, etc. I will be able to get a handle on how much detail and time I'm going to need to finish up the chronology paper. The alluvial sedimentology paper is going to take some time - because I'll have to abandon my ego and go through the reviewer's comments in detail.
Thursday, November 03, 2011
Thurs-Demo: The one with Terraces
Part of my research deals with the history of rivers. Well, a few rivers in particular, but they are an example of how the landforms associated with rivers and streams can tell us about past changes to the river system. Terraces are one of my favorite. Terraces reflect periods of transition for the river system. Periods when something happened - whether it be tectonics, climate, or changes in the base level (lowest point) terraces mark a change from a stream that is relatively "stable" to a stream that is able to erode down into its floodplain.
Callan, over at Mountain Beltway, had a post about terraces last year. The picture below shows some of the work I'm doing along the Red Cedar River - a tributary of the Chippewa River - which itself is a tributary of the Mississippi River.
Depending on how picky I feel like being, I count over six terrace levels - possibly as many as ten. One of the questions I'd really like to answer is "how did these terraces form?" Did they form as a result of changes in sediment supply? Cutting off sediment supply (or increasing water discharge) allows the stream to pick up sediment along the floodplain and erode downwards. Or base level drop? A drop in the main stream would lower the mouth of the tributary. This would increase the slope of the stream locally. Increased stream flow would increase erosion. I've sketched out the two most likely scenarios for the Red Cedar below (I'm ruling out tectonics for now, but isostatic readjustment as a result of glacial retreat may play a role).
It's important to note that these terraces may not be synchronous - depending on the rate of erosion, one part of the terrace may form much later than another. Also, the direction that the terrace develops is different. With sediment supply, the erosion starts upstream and progresses downstream. By contrast, a drop in base level occurs at the mouth first and erosion progresses upstream.
This is rather an abstract concept. It's hard to intuitively understand these processes. That's where the Emriver model comes in. By manipulating the system, it becomes easier to see what's going on. But how well does the Emriver replicate these terrace forming processes? Pretty good, actually. Here's a video where I managed to alter sediment supply (by limiting the sediment mobilized upstream) and dropping the standpipe to simulate a fall in base level. Pay close attention to the direction that the incision propagates.
Callan, over at Mountain Beltway, had a post about terraces last year. The picture below shows some of the work I'm doing along the Red Cedar River - a tributary of the Chippewa River - which itself is a tributary of the Mississippi River.
Depending on how picky I feel like being, I count over six terrace levels - possibly as many as ten. One of the questions I'd really like to answer is "how did these terraces form?" Did they form as a result of changes in sediment supply? Cutting off sediment supply (or increasing water discharge) allows the stream to pick up sediment along the floodplain and erode downwards. Or base level drop? A drop in the main stream would lower the mouth of the tributary. This would increase the slope of the stream locally. Increased stream flow would increase erosion. I've sketched out the two most likely scenarios for the Red Cedar below (I'm ruling out tectonics for now, but isostatic readjustment as a result of glacial retreat may play a role).
It's important to note that these terraces may not be synchronous - depending on the rate of erosion, one part of the terrace may form much later than another. Also, the direction that the terrace develops is different. With sediment supply, the erosion starts upstream and progresses downstream. By contrast, a drop in base level occurs at the mouth first and erosion progresses upstream.
This is rather an abstract concept. It's hard to intuitively understand these processes. That's where the Emriver model comes in. By manipulating the system, it becomes easier to see what's going on. But how well does the Emriver replicate these terrace forming processes? Pretty good, actually. Here's a video where I managed to alter sediment supply (by limiting the sediment mobilized upstream) and dropping the standpipe to simulate a fall in base level. Pay close attention to the direction that the incision propagates.
Subscribe to:
Comments (Atom)