Need Engineering Trade Journals

I am a member of AAAS, and while that organization’s Science News articles written by its journalism staff are long on who did the research and where they work, their articles are sadly short on the nitty gritty. Fortunately, AAAS also publishes the journal Science, which minutely details cutting-edge research applicable to multiple research disciplines. Good mag, that.

I love to read about science and engineering. Science indeed feeds the former, but not the latter. A long-ago workplace’s engineers used to pass around engineering trade magazines, which discussed details of the latest applications in engineering research. I read them as avidly as my engineering colleagues (I am a wildlife biologist). I miss those mags.

One article in particular, I believe in a magazine entitled Civil Engineering, was written by an engineer who immersed a “hardware cloth” wire grid into saltwater and applied a small current to it. Over a month-long period, a hard solid that looked like cement subsequently “grew” on the grid. He initially suspected it was a marine salt precipitate, but after turning off the power, it did not redissolve. He didn’t want to pay for a chemical assessment, but opined that the material might have been some kind of hydrated compound. Because (I think) he used raw saltwater, I wonder if there might also have been a microbial component. Whatever, thinking that it had potential as a building material, he patented it and dedicated the patent to the public. The popular press would never, ever do articles like that.

More recently, there have been a series of vapid articles in the pop press about a Netherlands architectural firm designing a floating town for Mauritius. Its goal is to stay ahead of global warming’s sea rise. The new town’s buildings will be on rafting platforms joined together and anchored in place within an atoll. The architectural drawings are all pretty faces, of course, but neither pop press articles nor company PR detail such things as what materials comprise the floats, platforms, infrastructure, and buildings. Yawn. How are individual floating pods interconnected? With steel cables? With wooden beams? How will they deal with fouling organisms that glom onto and weigh down the floats? Seascaping projects like this one fascinate me, but all the articles I’ve read about it so far (and I’ve looked hard!) are empty calories to my analytical mind.

Or how about Elon Musk’s fantasy about a Mars colony? What EXACTLY does he plan to do about the physiological impacts to the human body from long-term exposure to low gravity? There’s not a peep about that issue in pop press articles. Hellooo! Earth calling Mars!

So, I plan to spend a little time over the next few weeks looking at engineering and architectural trade mags to see if they might take me where I want to go, and at what cost. Do any of you engineers and architects out there have any pointers? TIA

 

My Florida Torrey 2020 Status

I am a Torreya Guardian, one of a dozen or so people who work to prevent the extinction of one of the most endangered conifers in the world. The Florida torrey, Torreya taxifolia, has an extremely restricted range that is located at the triple point where Florida, Georgia, and Alabama meet. Although it has protected habitat in Florida, especially within Torreya State Park and nearby conservancy preserves, it is there infested by a fungus (Fusarium torreyae) that kills nearly all torreys before they are mature enough to set seed. Connie Barlow reasoned that the best way to save the species was to assist in its migration to cooler climes where the fungus may not be able to survive. She and others collect seed annually for distribution to the rest of us. Hence, my plantings in the Blue Ridge Mountains of western North Carolina. So far, I have put 18 seedlings in the ground on my 2+ acres, 14 of which have survived to this day. The other four were killed by voles chewing through taproots blocking their way when digging their tunnels. This blog post documents the status of the remaining 14 as of today. The single torrey that was planted within the mature mixed forest here has grown the least, and now, nine years later, has grown to a height of only 13 inches:

The largest two were planted alongside my driveway where they get 4-5 hours of direct sunlight a day. Now, eight years later, they are 71 inches tall:

The others are intermediate in size according to the amount of insolation that they receive. Here's a couple of them:

Solar Greenhouse Thermal Mass Hydroponics

Many greenhouses today use thermal mass water tanks. The 26 ft diameter Open Spaces Growing Dome solar greenhouse that I manage for a friend at 3400 ft elevation in western North Carolina has one that might hold about 600 gallons. Climate zone maps say it is within zone 7, but I believe it might as well be zone 6 at that elevation. Whatever.

I have asked around on Facebook's greenhouse and general gardening groups whether anyone is using their thermal mass water tanks for hydroponic or aquaponic cultures, and have received zero responses one way or the other. My suspicion is that people who do so are doing it on a commercial scale, which is fine as far as that goes. However, there are many greenhouse gardeners who grow for their own and friends’ tables, so I think this represents a currently wasted opportunity. If you have a thermal mass water tank in your greenhouse, or are thinking about putting one in, consider adding edibles to those tanks. I don’t think you will find very much directly applicable information out there (and I could be wrong about that), but perhaps if we who do eat what comes out of our tanks, we can share what we have learned in Facebook greenhouse and gardening groups.

I started out by researching crops to grow on a small scale in the GH I manage. It turns out that there are few such crops, and many of them are invasive pests that can be illegal to grow; e.g., watercress (Nasturtium officinale), which grows rampantly in some of America’s natural streams. Other native wild species like yellow water lily (Nuphar advena) and wild rice (Zizania, four species) are too large and difficult to harvest from small water tanks. I uncovered no suitable aquatic plants, so I looked for wetland plants that might be grown on floats.

One of the most promising candidates is Chinese water chestnut (Eleocharis edulis). This is a small wetland plant that can be raised in shallow water in a matrix of organic mud (I don’t call it soil, as there is no such thing as a true wetland “soil”). I obtained ten corms of it from a nursery in Florida, then punched five half-inch holes in the bottom of a closed-cell foam packing tray and placed five corms in the holes equally spaced around in the tray:

I then added the other five corms and filled the tray with about two inches of organic mud. They took their sweet time to sprout and then grew relatively slowly, averaging maybe 14 inches in height by early July 2020 (week 13):

As of last week (week 31), some of the leaves had grown to a height of about 16 inches and had started to die back for the winter. I do not know if the original corms have budded new ones, as this is not obvious. They may have stored enough energy during this past growing season to add more corm/shoot growth in the coming spring, and I don’t want to retard that possibility by disturbing them now just prior to winter. About half of the mud is gone, presumably by decomposition, but possibly also by percolating down into the tank through the watering holes. I plan to add more mud during early springtime. In the photo, note the plants’ white roots floating just under the water’s surface:

There are a few small fish (unknown species) in the tank to keep mosquito larvae at bay. I was afraid the fish might eat the roots, but that does not seem to be a problem. There is a thick layer of algae growing atop the mud, and I wonder if it will adversely affect the plants, but that remains to be seen.

Despite the water chestnut’s slow growth, I was encouraged by the successful proof of concept, wherein the floating wetland bed remained afloat, the water chestnuts flourished, the mud acted as a wetland substrate, and nothing bad happened over the five-month experiment. However, further internet searches turned up no other suitably promising floating wet mud crops, so I turned my attention to drier floating substrates, and it being autumn becoming winter, settled on peas - specifically snow and sugar snap peas. I had already successfully raised those in outside beds nearby, so I knew they would work with the potting soil that was available.

This time, I used Styrofoam packaging material, again punched half-inch holes in the bottom for irrigation, and placed 1- to 2-inch rocks above the holes to elevate the potting soil above the water level and hopefully to keep most of the dirt from dropping through the holes. This is what it looked like one week after planting (late September 2020):

The pea seeds fairly leapt up out of the ground! Over the following weeks, the plants (vines) grew eight inches up and over the edge of the tank, another four feet down to the greenhouse floor, and then back up another two feet. That’s almost seven feet over 11 weeks, which was easily twice the length of pea vines grown outside in the garden bed during the summer. I don’t know if they grew faster in the greenhouse because peas are a cool season crop, but I also must admit that they have yet to flower and set seed. There could be a nutrient deficiency in the water tank, but that is hard to determine because water nutrient analyses are expensive and the county extension agency is oriented toward determining fertilizer levels in dirt, not water.

I like the idea of raising vines rather than bushes in the tank, because vines can grow over and down the sides of the tank whereas bushes (e.g., beans and tomatoes) could easily topple over if their substrates have no side support. I may try strawberries this coming spring.

Red Wolves?

Kimo Brown’s story today on Facebook (http://tinyurl.com/y6rxenfs) of his encounter with mustangs and rez dogs during morning yoga reminded me of a similar experience I had at Padre Island National Seashore off Corpus Christi, Texas, I think in the 1980s. It happened when a client organized a workshop attended by several members of our environmental consulting company, another consulting company, local university scholars, and state and federal agency staff. The group was primarily composed of wildlife biologists.

We met daily at the university over a week, did our workshop thing, and then retired at the end of each day to a local pub for chips, Tex-Mex salsa, and beer. Problem was, there was one big round table that most of the group sat at, but it wasn’t big enough for us all, so I wound up at a smaller table with grad students. The Big Table continued to talk about the project, but the grad students only talked about school funding inadequacies. After a couple of days of barroom boredom, I decided to investigate the Padre Island wilderness.

I drove across the causeway and parked, walked the seaside trail to a fine Seton spot, and sat down in the atmosphere created by wind in the sea oats, Gulf of Mexico small surf, and colorful sunset. I was totally alone. Despite the thriving city only a few miles away, I was the only person in the coastal barrier landscape.

The first evening I was there, and almost as soon as I sat down, Eastern Meadowlarks began singing. Theirs is a relatively monotonous, strident and reedy song, but I grew up with it in North Florida and find it familiar and comforting. This lasted for about 15 minutes. Afterward, there was about a five-minute interval carrying only the sounds of the breeze and the sea, and then Western Meadowlarks began calling. Their songs were far and away more melodious than their Back East brethren. It was my first experience hearing this species, and I was enthralled. I listened to it until they ceased singing, finished watching the sun go down, and drove back to the motel.

The second evening, I again went to that sweet spot and waited for the meadowlark opera to begin. As I sat there, however, I got the strange feeling that someone was watching me despite mine being the only vehicle in the parking lot. Turning around to investigate, I saw three large canids about 20 feet away staring at me from the sand dune ridgeline above... three pairs of wild, yellow eyes evaluating this lone potential prey victim sitting in a most vulnerable position. Not daring to even gulp, much less budge, I stared back. Two of them then turned and nonchalantly trotted away, but the third continued to meet my gaze for a moment longer and then also slipped off.

These animals were the size of large German shepherds, but the grad students the next day concluded I had merely seen coyotes. However, I have seen coyotes Out West and in the Southeast, and individuals of both populations are significantly smaller than shepherds. Furthermore, there was a small population of red wolves on that island back then. Perhaps I did just see coyotes, but the coyote is descended from wolves and their hybrids are fertile, so I prefer to believe that I saw wolves. Whatever, after they left, I listened again to the meadowlarks. East meets West sometimes inscrutably.

A Solar Greenhouse to Play In!

I have been helping a friend repair and put back into operation a 26 ft diameter geodesic dome solar greenhouse that was designed and sold by Colorado-based Growing Spaces.

She bought the greenhouse over ten years ago as a way to get her family to spend quality time together on a project. Her family scattered to the four winds over the years, and not having a green thumb she just ‘let it go.’ More recently, she decided to rehabilitate it as a way to grow her own organic veggies and provide a place for herself and her Buddhist group to meditate. I constructed a solar greenhouse in the late 1970s that followed the guidelines of the New Alchemy Institute (now called The Green Center), so now I get to play in a solar greenhouse again after all these years!

My friend flatly refuses to employ power from the local utility (Duke), instead relying on three small solar panels that came with the greenhouse: (1) a 12" x 24" panel powering a ventilation fan, (2) a 12" x 24" panel powering an under-soil heating system, and (3) a 12" x 12" panel powering a (bilge) pump intended to circulate water in the thermal storage tank. All three solar panels function fine and provide appx 12 vDC current, which obviously varies according to the amount of solar insolation available during the diel cycle as modified by weather.

The ventilation fan also works well; however, I am a bit confused about its thermostat. Currently, the fan turns on and blows outside air into the GH when inside air temperature drops to about 65 °F, and then turns off when greenhouse air rises to 80+ °F. That is obviously backwards from what it should do, and the manufacturer confirmed to me that the thermostat was probably wired backwards, but after reversing the thermostat’s internal wiring based on a diagram he sent me, it still turns on and off backwards. Maybe I only thought I rewired it correctly but actually didn’t? I’ll revisit this in the spring, but the fan is now disabled and shuttered for the winter.

The greenhouse’s two-foot-high internal raised beds are enclosed by concrete block walls, at the bases of which are layers of eighth-inch wire mesh (so-called ‘hardware cloth’) to ward off burrowing rodents. The beds encircle the greenhouse interior perimeter except at the door and water tank. The bottom halves of the beds are filled with native dirt, which is a rocky sandy clay that provides good enough drainage. The top halves of the beds are filled to an appx twelve-inch depth with potting soil (mostly pine bark with a little

humus and very little Perlite).

There are two four-inch diameter ribbed plastic pipes running the entire length of the perimeter beds at the interface between the native dirt and potting soil. The pipes lead from an air intake box near the center of the GH’s south side (the warmest place in the GH):

I replaced the seized-up original soil heater fan with a $10 computer cooling fan and hooked it up to the second 12” x 24” solar panel. When the sun is shining, the solar panel now powers the new fan, which sucks air into and pushes it through the two plastic pipes to heat the soils in the raised beds. Warm roots support veggies better than cold roots! This pic shows the exhaust end of one of the pipes emerging well above the raised bed to keep potting soil from falling into the pipe:

The water tank's bilge pump was seized up when I came on board, so it was discarded but not replaced. My friend said it never worked (!) and she didn’t miss it, so there are no plans to replace it. The electric wires from its solar panel are still in place but not connected to anything. I harbor thoughts of eventually installing a new bilge pump and using the water tank (pictured below) for more than just thermal storage, but that is a subject to write about on another day. In the spring of 2019, I plan to move the bilge pump’s solar panel to the southwest side of the roof and the soil heater solar panel to its southeast side. I will then wire the two solar panels in parallel to power the soil bed heating fan, which together should provide power for a longer diel period and heat the raised bed soils even better than originally designed.

The water supply for the greenhouse was originally a stop-and-waste valve spigot located outside the greenhouse about four feet away from the southwest ventilation panel. This had several undesirable results, including (1) having to run a hose from the spigot into the greenhouse through the SW ventilation panel, which was inconvenient and in the way of gardening operations, 

(2) the SW ventilation panel was never completely closed because the hose was kept there, causing warm greenhouse air to escape to the outdoor winter environment, and (3) the spigot was destroyed twice in freezing weather after being left on due to forgetfulness. I convinced her to let me and her handyman move the spigot to the inside of the greenhouse, which was done in December 2018, and I then attached a four-way brass water distributor (and a plastic wye) to it to provide five protected tap water sources inside the structure.

Next, I connected two soaker hoses to the distributor. For the short raised bed located along the greenhouse’s west side and beyond the door, I cut a short section from a garden hose, added male and female connectors to the severed hose ends, and ran the short hose to the short bed to connect into a 25 ft long soaker hose. This photo shows the hose running vertically along both lower sides of the door (the hose is also buried four inches under the floor sand).

The second soaker hose, 50 ft long, was attached to the water distributor and then run out and looped back to irrigate the long raised bed. Soaker hoses have small pores that deliberately leak water for irrigation, but some of the pores are large enough for water to squirt out several feet beyond the raised beds and be wasted. Therefore, I buried both soaker hoses 2-3 inches deep in the potting soil to capture all of the irrigation water. These two soakers irrigate nearly the entirety of the raised beds, excluding only the end of the long bed which is not yet completely filled with potting soil or contains any plants. That location will be topped up with potting soil and vegetated in the spring of 2019, at which time I will add another 25 ft long soaker hose to irrigate it.

The greenhouse has a lot of air leaks, allowing air to somewhat freely pass in and out of the structure. This undesirably cools the interior in winter, although probably also helps to beneficially reduce overheating in summer. Leaks are caused in several ways, and I have plugged some of them, but much more repair will be needed next year. As mentioned above, one leak was stopped by moving the water spigot inside the greenhouse, thus eliminating the need to run the irrigation hose through an always-open vent panel. A second leak was closed by replacing a rotted structural 2x4 that a vent panel was attached to. A third leak was fixed by reseating weather-stripping that had become loose and sagged away from a vent panel over time. A fourth leak was mostly closed by replacing two rotted structural 2x4 boards that were fitted horizontally to the outside Hardy-board wall. Finally, several vent panels did not close completely because the aluminum strips that cover and protect vent panel junctions were too long; these I cut shorter with tin snips.

The fourth leak mentioned above was difficult to repair, as the weight of the greenhouse’s transparent panels was upon the two rotted 2x4 boards. Furthermore, additional 2x4s atop the Hardy-boards are rotten and still need replacing, which will be a two-man operation that will be done during 2019. The greenhouse owner is somewhat sensitive to pressure-treated wood, so the original construction used untreated redwood or cedar 2x4s. While redwood, cedar, and some other woods are naturally rot-resistant, they certainly are not completely so, and we will be looking at alternatives come spring.

We have also had to learn a lesson in varmint control. The entire floor of the structure is underlain by eighth-inch wire mesh to prevent rodents from burrowing into the greenhouse. This includes under the raised beds, as mentioned above, and under the central floor’s four-inch-thick layer of coarse sand. However, today I spotted on the bottom of the water tank a drowned mouse that evidently fell in and could not climb out. We had been wondering what was eating the leaves of the parsley and red Russian kale, and were advised by neighbors that it was probably slugs, so we were planning to install beer traps. However, the mouse could also be the culprit, as a cursory search has yet to turn up a single slug and there are still many holes in the walls that need to be plugged. What do you think?

Lastly, the photo below of the center of the greenhouse should give you some idea of how much room there is inside. It is large enough to add a central raised bed, but we will probably not do so since she wants the space for meditation sessions. I hope to be able to show you more pics over time as we finish topping up and planting the existing raised beds, adding the additional soaker hose, adding hanging baskets, and allowing warmer weather over the upcoming spring and summer to create a lush indoor green space. I might even install some solenoid valves to completely automate the irrigation system.

Carolina Wrens in the House

A few days after I returned from Florida to my place in North Carolina at the beginning of March, a pair of Carolina Wrens (Thryothorus ludovicianus) built a nest on top of an electric outlet box in my house. The house was (is) still under construction, so they could easily get in and out at will. Over the next week, the female laid five eggs in the nest. I didn’t want to quit working on the house and didn’t want to evict the birds either, although I had already run off four or five flying squirrels (Glaucomys volans) from the eaves and a major nest of house mice (Mus musculus) from the basement. So, I just left the birds alone and went to work on the house.

The wrens and I puttered around each other, they warily and me deliberately. I tried to give them as much personal space as I could, but house construction went on regardless. Over the next two months they incubated the eggs and fed the hatchlings in the nest until yesterday, when the nestlings fledged. I don’t know how many of the original five survived, but I counted at least four. This photo shows three of them in the house:

The four young-uns and their parents freaked out when I arrived that morning, but three of the nestlings were able to fly from the nest area up to the soffit and then across and down into a mountain laurel bush (Kalmia latifolia) outside where they remained and rested for a while. The fourth nestling, apparently the runt of the litter, was too weak to make it up to the soffit. It tried to hide from me and then escape my gentle clutches, all to no avail:

I easily captured it and placed it outside in the shrubs where I had seen the others, but by then they were gone. Hopefully, its parents heard its weak chirps and came to rescue it, but it was no longer there when I checked on it later.

Of course, I immediately removed the nest from the house, and they have not since replaced it. If they try to do so, I’ll delete it before they can lay more eggs in it. However, my guess is that they have built a second nest elsewhere outside away from the Big Bad Buford.

I am amazed at how many species of wildlife have already tried to move in on me this year. Besides the flying squirrels, house mice and wrens, there are mud daubers, paper wasps, a scorpion, and numerous spiders. I am not alone.

Flying Squirrels in My Corner

Every now and then a flying squirrel has been spotted in the house I’m constructing. Yesterday, I noticed that the volant rodent was using a spot on the outside of the house as a urinal. Pretty ugly. Today, I went on a squirrel nest hunt and found it in a boxed-in corner soffit just under the roof. I opened the wood face of the box and things got uglier. This pic shows the wood stained by urine, and to its left below you can glimpse the nest:

Peeking inside the box, you can see the nest a little clearer. It is composed of wheat straw I bought for the yard and shredded paper towels from inside my pickup. I am not just their landlord:

Looking a little closer, here’s one of the culprits:

All four corners of the roof have such “box.” The other three each had a single access hole, all of which I immediately covered with new wood plates. The corner nest box had three access holes, however, one being significantly larger than any of the other access holes and probably the reason they went for this particular abode rather than the others. I constructed three wood plates to cover the nest box’s access holes and sat back to wait for dusk. The idea is to fasten the wood plates in place so they can’t get back in after they leave their nest for their nightly foray. The squirrels cannot get into the other three corner boxes either, so they are forced to find a home away from my home. Hopefully, opening the face of the box and exposing the squirrels to predators will encourage them to skedaddle.

But wait! There’s a winter storm coming. Cold rain is expected and we could get sleet or even 1-3 inches of snow. Without an insulating nest to protect them from the coming chill, the squirrels could be killed if I evicted them just before the storm. They mate in Feb-Mar and give birth 40 days later, but this being a relatively cold location gives me hope that this animal will not drop her pups until April.

I guess waiting until several days of good weather are upon us would be the humane thing to do. That might give them time to construct a new nest elsewhere before I pull the old nest out and clean things up.