Horsetail

This is my first post in a couple years, and I’ve been sitting on these pictures for a while. The picture above is a Horsetail. Although it looks like a mushroom, this is actually a plant. I don’t know which species it is, but Horsetails all belong to the genus Equisetum.

These odd plants look like they belong in another time, with good reason. Like ferns, horsetails are plants that predate flowers. Instead of reproducing with seeds, Horsetails have spores. This type of plant (sporophyte) dominated the world in the paleozoic, before flowers even existed, hundreds of millions of years ago.

Wikipedia does a decent job of explaining how sporophytes work. The point is that these  horsetails are strange. Alien. Living fossils. A closer look shows just how alien they really are:

 

Links:

https://en.wikipedia.org/wiki/Equisetum

https://en.wikipedia.org/wiki/Spore

http://www.newyorker.com/magazine/2011/08/01/hunting-horsetails

 

Bringing 3D Printing to Developing Nations

Joshua Pearce’s group at Michigan tech have developed a mobile solar-powered 3D printer, which could hypothetically bring 3D printing to off-grid communities in developing nations. They combined a foldarap, laptop, photovoltaics and batteries for a self-powered, self-contained system. The team designed two models: community-scale and ultra-portable scale. The community-scale system would be dedicated to a single village or school. The ultra-portable system fits in a single briefcase, and would be brought to the villages that need it most. Or, you could take it and become some sort of traveling printer salesman.

In the paper, they print an avocado pit germinator, tweezers, and battery terminal separators as examples of useful tools a village might need. The ability to print mechanical spare parts in an area that can’t just order from Amazon could be very useful.  The printers might even impact health, with more medical devices, being designed and printed daily.

Up Close with Hops: The Flower

The flowers are the crown jewels of hops. When mature, they look like soft green pine cones dangling from the bines. They are real flowers, though they’re variably called cones, strobiles, or inflorescences (though technically, that’s only a cluster). Hops plants are dioecious, meaning plants are either male or female. Only the female cones are used in making beer, because they’re larger and contain chemicals like lupulone and humulone, which add flavor to — and help preserve– beer.

Immature flowers

The flowers are directly attached to a stem-like “strig.” The strigs grow from axillary buds, usually on lateral bines. They can also grow from the main stem, but the lateral bines are where most flowers are. The buds initially look like tiny koosh balls, and only appear after the hops is almost done growing upward. They slowly get  bigger until the end of the season, when the lupulin glands start to produce the valuable resins. Until this point, the flowers don’t smell or taste like anything special.

Lupilin is the bright yellow resin responsible for the flavor and aroma. The unique chemical make-up of the lupulin is what differentiates different strains of hops. If the lupulin has more alpha acids, then it can make the beer more bitter. Other compounds can give a citrus taste, or a pine taste. Virtually all of these flavors are due to terpenes of one kind or another. The lupulin glands are located within

Focus-stacked composite image of lupulin glands at 20x

It’s important to keep only female plants on a hops farm, because flowers that produce seeds don’t produce much lupulin. Energy is diverted away from making flavorful oils, and into making a viable seed. I believe my hops were fertilized by some wild plants that I haven’t been able to find. Hops farmers don’t even have a use for the seeds, because when they need more hops, they clone old plants. While it’s possible to grow hops from seeds, but 50% will be male plants. And the other 50%  of hops will have a different flavor profile than its parent. Hops varieties, like apple varieties, are all genetically identical to one another. So a cascade hops in Maine will have the same genetics as a cascade hops in Oregon. There are still breeders of hops, who use seeds to create new varieties, but this is a very long and specialized process. When I make a post about hops roots, I will talk some about the rhizomes which enable cloning of hops.

On the right are two normal, unseeded cones. Just to their left are the small, seeded flowers.

The Ghost Plant

Monotropa uniflora is usually seen in late summer or early autumn, poking through oak and pine leaves. The strange plant is translucent white, and has a rubbery texture that’s cool to the touch. Their likeness to a dead man’s fingers is probably why it’s called a corpse plant, or ghost plant. It also has the less morbid name, ‘Indian pipe plant’. The unique look of this plant is only possible because of its unique ecology.

The total lack of chlorophyll and other pigments is possible because this is a parasitic plant. Monotropa species are unusual plants that are actually up the food chain. They’re two whole levels above where photosynthesis happens. Unlike carnivorous plants, which only eat other species for their nitrogen content, Monotropa derive all of their energy from their fungal hosts.

Ghost plants’ energy sources are the critically important mycrorhizza, which are critically important to forest ecology. These fungi form symbiotic relationships with trees and other plants. The mycorhizza receive carbon (energy) from the tree roots. The trees also benefit from this relationship, because the help the trees uptake nutrients. The ghost plant then comes along, and takes the fruit of the fungis’ labour. I drew a crude diagram showing the relationships between the tree, fungus and Monotropa.

Ghost plant epidermis at 100x. The leaf completely lacks any pigment.

Color

Green leaves are green because chlorophyll is green, and carrots are orange because of carotenoid pigments. However, with the ghost plant, there no single white compound responsible for the color. Instead, the color is likely from scattering. All visible light enters the cell; rather than being absorbed by chlorophyll, the light then bounces around the particles within the cell walls. This scattering process throws back equal amounts red, green and blue, so the light is white. Mostly.

The inner stem and flower will sometimes have a pink hue. I don’t know if this pigment is taken from the environment, or if it’s produced by the plant to help attract polinators (like bees). The plant has black spots, which appear to be dead/dry specks of the plant. It also occasionally has light blue, which could be due to oxidative damage. The literature on what little color these plants have is sparse.

Dead Monotropa

If you want to find of these, they’re found in most of the US except the rockies.  They’re usually found a few feet from the base of a pine tree, and start emerging in mid-August. You might also find dried up ones, like the picture above. Although of no economic or ecological importance, they’re still pretty cool to look at.

Some Papers:

Click to access Monotropa%20uniflora.pdf

Click to access Mycorr%282005a%29Mass.pdf

http://www.amjbot.org/content/96/7/1337.full

Up Close with Hops: The Stem

This year, I grew hops for the first time. Hops are the vine-like plants that give beer the majority of its bitterness and floral flavours. There are a number of cultivars of hops with different characteristics, and I got the cascade variety. Cascade has the citrus flavour that’s popular in many west coast pale ales (eg. Stone IPA or Sierra Nevada pale ale).  There’s a wealth of information on how to grow and harvest hops, but I didn’t see too much content about their anatomy.

Hops have long, climbing stems that wrap around a string or trellis to reach heights up to 30 feet. Every year, numerous stems sprout from the root ball. They could number in the hundreds, but a hops farmer trims them back to under 10. After sprouting, they stretch out, searching for something on which to climb. They grow vigorously upwards until midway through the season, when they start sending out lateral branches. It’s these lateral stems where the vast majority of flowers are produced.

In the wild, they can climb up trees, to get better light and spread pollen via the wind. Cultivated hops don’t need to spread pollen, but they still need to be in the air to produce flowers. The flower clusters have some weight, and can be battered by winds. So the stem needs to be tough. It also needs to transport water and nutrients up the great heights.  This post looks at two adaptations of the stem, to help climb and transport water.

In the picture on the right, hops looks pretty viny. However, they’re not vines. Vines have tendrils which extend from the stem, to grab hold of structures to climb on. In the picture below, you can see a grapevine tendril grabbing onto a little twig.  The vine itself doesn’t wrap around its supports. However, with bines, the entire stem needs to wrap around its support.

A grapevine tendril clinging to a twig

Bristles on a developing hops bine (20x)

Hops bines are able to grip with the aid of bristles on the stem. The bristles are modified epidermal cells, and look like tiny rose prickles, which are also epidermal outgrowths*. In mature hops the bristles can scrape or irritate skin if you’re not careful. They aren’t vicious, but the hooked shape is probably no surprise to anyone that’s felt the stems.

The bristles help the bines grip, and climb tens of feet into the air. The stem also needs to transport water. Lots of water. A well-established hops plant supposedly is able to grow 1 foot a day during the peak of the season. I took some pictures of the cross-sections of an immature and mature stems. The first thing that struck me is that they’re hexagonal. I don’t know how common that is in the plant world, but it looks pretty near. Many plants in the mint family (Lamiaceae) have square stems. I’d be interested to see other hexagonal stems.

Young stem cross-section. 20x

Because they need the ability to grow almost a foot a day (at peak), they need a lot of water. If leaves need a lot of water, then the stem needs vascular elements to move water up and nutrients down. The immature cross-section was taken from a 4 inch bine. The mature cross-section was taken near the bottom of a 10 foot bine.  You can see how the mature bine needs has much thicker vessels to transport more water.

Cross-section of mature bine

*Roses do not have thorns, which only grow from the base of a leaf or branch (at the axillary bud). Thorns are modified leaves. Prickles are modified epidermis. Technically, no rose has a thorn.

ATX to Bench PSU conversion. Cleaning rust with electrolysis.

The ATX bench power supply. There are 3 red ports for 12v, 5v and 3v rails. The black port is ground.

This is a good place to start a blog.

Tired of using wall wall wart supplies for any electronics projects, I decided I need a real bench power supply. At the same time, I had an unused ATX power supply, and a sweet toggle switch looking for a good project. There are already a variety of ATX to bench supply conversion projects, ranging from very simple, to moderately complex.  I wasn’t thinking about blogging at the time, and didn’t feel like dismantling the whole thing. So there’s not a lot of pictures of the construction. No two of these ATX bench supplies are the same, so it wouldn’t have helped much anyway. This post isn’t a how-to, it’s showing just of one variations of the ATX bench power supply.

This design is definitely on the simple end of the spectrum. It has two features that set it apart from most of the designs: A sweet missile launch switch, and the ATX connector on the PSU isn’t damaged. This 500W Antec looks pretty decent, so I didn’t want to destroy the possibility of ever using it in a computer. Instead of hacking the original supply to pieces, this has a small control box bolted to the top of the supply. The standard ATX cord that would normally connect to the motherboard is instead connected to the back of the control box. The only real modification to the PSU was drilling two small holes in the top, to connect the control box.

The red LED is standby. The Blue LED turns on when the 12v, 5v and 3v supplies are ready.

Rear view of the ATX plug.

Design

Parts list:

• Antec SP-500 500 watt power supply
• Sweet toggle switch
• Blue LED
• binding posts
• ATX connector
• 22 gauge stranded wire
• 2”x3”x1.5” aluminium enclosure, with 2 screws
• Two nuts and bolts

Some PSUs need a dummy load on the 12V rail. This Antec doesn’t, so the binding post circuits are straightforward, and a diagram isn’t needed. One 12v, 5v, 3V and ground pin from the ATX connector goes to the respective binding posts. In theory, the multiple 12v rails could be combined for higher amperage, but that would be overkill for what I need. Also, I might need a lower gauge wire for that.

Toggle Switch circuit

The LED toggle switch circuit is a little counter-intuitive and a diagram is helpful. Your computer power supply is usually left “on” with that small black toggle switch in the back. But it’s only once the motherboard demands power, that the PSU energizes its 12, 5 and 3 volt rails. It’s the PWR_ON pin on the ATX connector that signals the PSU to turn fully on. So there’s two toggle switches for power. When the main, back toggle switch is in the on position, the LED in the toggle switch turns on. That’s the sign it’s “armed.” This is the counter-intuitive part. The LED gets power from the PWR_ON pin on the ATX connector. The PWR_on pin is high, and the LED/resistor in the switch doesn’t tie it low. However, when the switch is flipped, the red LED is shorted, and the PWR_on pin is tied low. Once the PSU’s power is stable, the PWR_good pin is high, lighting up the soothing blue LED.

Putting it together

I put holes in the aluminum enclosure for the ATX female connector, the toggle switch, the LED, and the binding posts. There were two holes added to the bottom for securing it to the top of the PSU. Securing the box to the top was the only time you’re at risk for a big shock, since it involves opening up the ATX case, and drilling holes in the top to match up with the holes in the control box.

Inside the control box

Once the box was finished and secured, I soldered short sections of wire to the relevant pins on the female ATX connector: Ground, 12V, 5V, 3V, PWR_ON, and PWR_GOOD. With the wires in place, I added the switch, LED and binding posts to the enclosure (these have nuts and washers to secure it to the case). I finished the wiring everything and, lacking shrink tubes, insulated the wires with electrical tape. After a few test runs, the last thing to do was hot glue the ATX conector to case. It’s a snug connector, and takes some force to connect or disconnect. Hot glue works miracles.

Testing With Electrolysis

Before electrolysis

According to the sticker on the side, the output of one 12V rail is 19 amps – a deent amount for an electrolysis setup. I had these pliers that I found outside, completely rusted shut. No amount of prying would open this piece of crap. The quick and dirty process to clean electrolytically is:

fill some container with water, and saturate it with baking soda.

Connect the tool to be cleaned to some wire. This will connect to the anode. You want the metal reduced, adding electrons, so it’s connected to the ground.

During electrolysis

Then, some sort of sacrificial metal is needed. For this, I used some old aluminum foil. Make sure the aligator clip doesn’t get submerged with the aluminum, or else the clip will get corroded as well.

That’s all there is to it. I flipped the switch, and in an hour most of the work was done. I pried it open, sanded some to expose new metal. Opening still took quite a bit of force. I did this a couple more times over the course of an hour. As you can see, it took care of all the rust on the pliers. However, it was so badly corroded from before that it’s pitted.

This winter, I just might have to check its capabilities of charging a car battery. Hopefully not, though.

After electrolysis